6428 User Manual RevA
Contents
1. 0 cece eee eee 35 Principles of Operation 57 OVEIVICW 3 esis io wk Geek eine tinea aeons 57 General Theory vcrscersie edd eves cian 57 Changing the AC Voltage Selection 61 Troubleshooting 65 Front Panel Controls Won tWork 65 Computer Control Doesn t Work ec eee 65 Wavelength Not Set to the Start Wavelength 65 Scans VV Ol Coltahtv witeianiacaasaatercauernien s 66 Error COGGSs ar Orci Caleta e A ates 66 Calibrating the Laser 0 cece cece eee eee 67 Customer Service 69 SEVICE es tics teased A a a a awa hedens 69 Technical Support s 24 22 00 cesta ciesirctcmcntione eee 69 Appendices 71 Appendix A Physical Specifications 71 Appendix B RS 232 Connector Wiring 72 Appendix C Specifications s s 73 4 Contents NEW FOCUS Inc ao 6400 rev A fm Page 5 Friday June 11 1999 4 41 PM a User Safety Introduction Your safe and effective use of this product is of utmost importance to us at New Focus Please read the following laser safety information before attempting to operate the laser Laser Safety 6400 Series Lasers The laser radiation emitted from this unit may beharmful Always follow these precautions e Avoid direct exposure to the beam e Always wear protective goggles or eyeglasses appropriate for working with laser light e Avoid looking at the beam directly e Beawareof and follow the warnings on the safe2. Error 15 Tunable Laser Cavity EEPROM stability error or there is a compatibility conflict between controller and Tunable Laser Cavity Error 16 Motion control board error Error 17 Communication error between microprocessor board and motion control board Error 20 Over Current protection Error 21 Interlock error or Over Power protection If you are not using the safety interlock feature page 7 check to makesurethejumper on the back of the controller is securely in place Error 30 Motor controller error Calibrating the Laser You can calibrate the laser power or wavelength to an external meter using the computer interface To calibrate the power see page 42 to add an offset to the wavelength see page 44 6400 Series Lasers Troubleshooting 67 gt ao 6400 rev A fm Page 68 Friday June 11 1999 4 41 PM 68 Troubleshooting NEW FOCUS Inc ao 6400 rev A fm Page 69 Friday June 11 1999 4 41 PM Customer Service Service We designed the 6400 Series lasers to be maintenance free no scheduled service actions are required If your laser does require service repair or calibration please call for a Return Authorization Number before shipping the unit to New Focus There areno user serviceable parts inside thelaser Unauthorized opening of the Ss laser will void the warranty and may result in burns dectric shock misalignment WARNING of thelaser cavity
3. chapter beginning on page 27 for details 10 Getting Started NEW FOCUS Inc fd 6400 rev A fm Page 11 Friday June 11 1999 4 41 PM 6400 Series Lasers Set the power to minimum For safety turn the Power Adjust knob counter clockwise until it stops to set it to minimum power Activate the laser Push the Laser Power button The button will flash for 5 seconds before current flows through the diode and the laser begins to emit light to the beam Set the operating power Turn the Power Adjust knob clockwise to set the laser s output power the units are dBm To prevent damage to the laser diode the factory has limited the maximum current to thelaser diode the maximum is wavdength dependent W hen you reach maximum power for the current wavelength the controller will engage thecurrent limiter and the power display will start to flash Set the system to track mode To manually set the wavelength the system needs to bein track mode A light in the Track button indicates when the system isin track mode If it isnot lit press the Track button to turn it on Set the Wavelength Turn the Wavelength Adjust knob to set the wavelength This will allow you to tune the laser with a resolution of 0 01 nm For 0 001 nm resolution press the Scan button and then turn the knob Scanning is discussed on page 21 10 Turn the laser off To minimizethe risk of power surges damaging the laser dio
4. 6400 rev A fm Page 27 Friday June 11 1999 4 41 PM a Computer Control Introduction The 6400 Series can be operated remotely through either the parallel EEE 488 GPIB interface or the serial RS 232 interface Most computers have RS 232 interfaces built in In order to use the IEEE 488 interface a special card or interface box is necessary The EEE 488 interface is many times faster than the RS 232 interface and can be used to communicate with up to 30 instruments at the same time RS 232 is limited to communication with oneinstrument at atime Upon receiving acommand over the computer interface the front panel functions are locked out Use the Local button on the front panel to re enable the front panel All front panel operations are available through computer control In addition several functions are unique to computer control Before attempting to communicate with the instrument you must set the device address for IEEE 488 or the baud rate for RS 232 via the front panel Using the IEEE 488 Interface 6400 Series Lasers ThelEEE interface also known as the General Purpose Interface Bus or GPIB isa standard interface used for personal computers to communicate with laboratory instruments Several manufacturers make printed circuit board cards that plug into the computer allowing it to communicate over the IEEE interface The card s manufacturer can provide information for configuration wit
5. and or irreparable damage to theinternal components Technical Support Engineers are on duty at 408 980 8088 from 8 30 5 00 PST Monday through Friday excluding holidays to answer questions about the performance or operation of your laser For quickest response ask for Technical Support and have your model and serial number available The model and serial number can be read from the certification label on the back panel of the laser You can also send technical questions by email directly to our Technical Support department at techsupport newfocus com Wewill typically respond to email within one business day 6400 Series Lasers Customer Service 69 ao 6400 rev A fm Page 70 Friday June 11 1999 4 41 PM 70 Customer Service NEW FOCUS Inc fd 6400 rev A fm Page 71 Friday June 11 1999 4 41 PM Appendices Appendix A Physical Specifications Figure 9 Front view and i side view of the pa pera ea 6400 Series laser 16 80 426 7 V Telecom Test Laser va tis 5 20 L n 132 1 17 50 444 5 gt 4 2 0000 o o 5 56 eeo 141 1 0000 0 C i Controller Weight 34 Ibs 15 4 kg 6400 Series Lasers Appendices 71 a e ao 6400 r
6. EXPOSURE DIRECT EXPOSURE TO BEAM INVISIBLE LASER RADIATION EMITTED FROM Power output THIS APERTURE Wavelength P CLASS IIIB LASER PRODUCT V Telecom Test Laser 6428 Made in USA J amp 6 User Safety NEW FOCUS Inc s p fd 6400 rev A fm Page 7 Friday June 11 1999 4 41 PM Figure 2 Certification label Model Number on the back of the Serial Number laser fhemitaciur di p NEW FOCUS Inc 2630 Walsh Ave Santa Clara CA 95051 0905 This product conforms to the applicable requirements of 21 CFR 1040 10 and 1040 11 at the date of manufacture Using the Safety Interlock The safety interlock connector on the back of the controller is provided for external safety systems The system is shipped with a jumper across theinterlock terminals Do not removethis jumper unless you are using the safety interlock feature the laser will not emit light unless the interlock circuit is closed The circuit carries 15 V DC 6400 Series Lasers User Safety 7 ao 6400 rev A fm Page 8 Friday June 11 1999 4 41 PM amp 8 User Safety NEW FOCUS Inc e ia gt ao S 6400 rev A fm Page 9 Frid
7. HM20 H3 00 C1 00 Manufacturer New Focus Model 6400 Serial Number HM 20 Motor Firmware Rev 3 00 Control ler Firmware Rev 1 00 Operation Complete Query Syntax OPC Description Returns 0 if a long term operation is ongoing Returns 1 if no long term operation is ongoing The laser has four long term operations e Scanning OUTPut SCAN START e Resetting OUTPut SCAN RESEt e Scan Maintenance OUTPut SCA N MAIN e Set Wavelength SOURce WAVElength Starting any of these operations clears the OPC sta tus bit When the laser returns to the start wave length or reaches the target wavelength the O PC status bit is set to 1 The bit is also set to 1 if the movement is interrupted either with SCAN STOP which interrupts a scan or reset or OUTPut TRACk OFF which interrupts a wavelength set Argument Response None 6400 Series Lasers Computer Control 35 ao 6400 rev A fm Page 36 Friday June 11 1999 4 41 PM E 36 Computer Control Start Maintenance Cycle Syntax OUTPut SCAN MAINtenance Description Initiates movement of all mechanical parts and per forms a tuning routine This same routine is per formed whenever you turn on thesystem keyswitch The full cycle requires less than 30 sec onds Thelaser returns to the start wavelength when the maintenance cycle is complete Periodic use of this command will extend the life time of the laser and improve wavelength accuracy Onceever
8. Principles of Operation NEW FOCUS Inc fd 6400 rev A fm Page 61 Friday June 11 1999 4 41 PM Changing the AC Voltage Selection The laser controller can operate at 100 120 220 or 240 V AC at AC frequencies of 47 63 Hz The unit is configured at the factory for the standard AC voltage of the purchaser s country To check the voltage setting look at the voltage indicator on the back of the laser controller Figure 6 AC power module ae Voltage indicator amp voltage indicator 3 To change the operating voltage 1 Makesurethelaser power is off and the power Keyswitch isin the off position Disconnect theAC power cord 3 Open thecover of the power module on therear panel with a small blade screwdriver or similar tool 6400 Series Lasers Changing the AC Voltage Selection 61 fd 6400 rev A fm Page 62 Friday June 11 1999 4 41 PM E a Figure 7 Power Module with the cover open AC voltage selection wheel Y Fuses amp fuse holders 4 RemovetheAC voltage selection wheel from the unit Do not attempt to rotate the wheel while it is still in the power entry module the wheel must be removed turned and then reinserted for proper operation 5 Reinsert the wheel into the module so the desired AC voltage can be viewed in the power module window 6 En
9. ao 6400 rev A fm Page 74 Friday June 11 1999 4 41 PM 74 Appendices NEW FOCUS Inc
10. the grating and the end mirror determines the lasing wavelength Tuning is achieved by varying the angle using a brushless DC motor to rotatethe end reflector Continuous mode hop free tuning requires selecting an appropriate rotation point Discontinuous tuning characterized by periodic mode hops results from two competing wavelength selection constraints the mirror grating angle and the laser cavity length The laser cavity length L defines a discrete set of possible wavelengths or modes Ay that can lase given by the equation L NAy 2 N integer The grating equation insists that A A sin 6 sin 84 where A refers to the groove spacing of the grating while 6 and 6 refer to the incident and diffracted angles of the laser beam Rotation of the end mirror causes parameters in both equations to change An appropriately selected point of rotation synchronizes the two such that the cavity length remains the same number of half wavelengths long as the mirror is being rotated Thus mode hop free tuning is achieved W hen this condition is not met the lasing wavelength will periodically hop from onemodeto thenet e g from N to N 1 asthelaser istuned Themechanical design of the 6400 Series laser provides truly mode hop free tuning The laser controller provides current and temperature controls to the laser cavity as well as manual and computer controlled input output interfaces The low noise current supply drives the diode in t
11. the wavdength from the front pand To return the controller to local front panel control press the Local button on thefront panal Understanding the Command Types There are three types of commands understood by the laser controller Set commands Query commands and Sense commands e UseSet commands to set or change a value Examples would be commands that turn on the laser or set the operating power e UseQuery commands to check the user or factory set values of the laser Examples include checking the set value for the power and checking the start wavelength for scans e UseSense commands to determine the actual values for the laser properties at any given time For example to check the actual Operating current or the voltage from the Detector Input 6400 Series Lasers Computer Control 29 ao 6400 rev A fm Page 30 Friday June 11 1999 4 41 PM Controller Responses All commands evoke a response from the driver set commands return an Ok when executed If you are using RS 232 the response is sent immediately with IEEE 488 the response is loaded into the output buffer a first in first out buffer with acapacity of 5 messages Programming for the 6400 Series Laser When programming for the laser keep the following rulesin mind e With GPIB all commands are issued using the BWRT function call To read the controller s response to a command use the IBRD function call e For RS 232 operatio
12. 99 4 41 PM Sense Wavelength Syntax SENSe WAVElength Description Returns the current wavelength of the laser This value will match the front panel display Each laser is calibrated with respect to wavelength at the factory and a calibration table loaded into the Tunable Laser Cavity Response Wet ux cae Units nanometers nm Example SENS WAVE gt 1550 025 The wavelength is 1550 025 nm Sense Level of Current to Diode Syntax SENSe CURRent LEVel DIODe Description Returns the magnitude of the laser diode cur rent in milliamperes The value returned is the same as that seen on thefront panel of the con troller at the time the command is executed Response Wit Units milliamperes mA Example SENS CURR DIOD gt 59 2 38 eComputer Control NEW FOCUS Inc ao 6400 rev A fm Page 39 Friday June 11 1999 4 41 PM Sense Temperature Syntax SENSe TEMPerature LEVel LASEr Description Returns the temperature of the laser cavity N ote The laser controller actively stabilizes the temperature for optimal performance If the system is exposed to environments outside the operating temperature of 15 35 C andisunableto maintain the cavity temperature thetemperature display will flash If this occurs shut down thesystem until the environmental tenperature returns to this range Response A E Units C Example SEN S TEMP LA SE Soi The
13. Computer Control chapter beginning on page 27 RemotelIndicator This indicator is lit whenever the controller is under computer control via either the IEEE 488 GPIB or the RS 232 interface See Computer Control on page 27 Wavelength Temperature Current and Power Displays Show thestatus of the different laser parameters as well as errors and system identification information Units arenm C mA and dBm respectively The Temperature display indicates the laser cavity temperature The laser controller actively stabilizes the cavity temperature for optimal performance The system is designed to operate in environments from 15 35 C if thesystem is exposed to temperatures outside this range and is unable to maintain the cavity temperature the temperature display will flash If this occurs shut down the unit until the environmental temperature returns to the operating range The current changes with the power and wavelength it is not adjustable You can modulate the current through a back panel BNC input see page 24 The display does not reflect any current modulation Scan Speed Switch Hold this switch up to view or set the scan speed General Operation 15 o ao 6400 rev A fm Page 16 Friday June 11 1999 4 41 PM 16 General Operation 9 10 11 12 13 14 15 Track Button Switches the laser between track mode where you can specify a
14. M 0 90 gt OK You will not notice any change without an external power meter which will read 10 higher than it did before with the same power level displayed on the laser s front panel Query Power Trim Syntax SOURce POWer TRIM Description Checks the trim applied the laser output power The trim is used to calibrate the laser to an external power meter Response XXX Example POW TRIM gt 1 12 The laser has been adjusted to decrease the output power by 12 10log 1 12 0 5 dB 42 Computer Control NEW FOCUS Inc ao 6400 rev A fm Page 43 Friday June 11 1999 4 41 PM Wavelength Commands Set Wavelength Syntax SOURce WAVElength lt val MIN MAX gt Description Switches the laser to track modeand drives the laser to the specified wavelength the laser s minimum wavelength or thelaser s maximum wavelength Theminimum and maximum values are laser dependent and may be queried see next page If the valueis out of range the laser returns an out of range error and no other action is taken Argument x XXX MIN Or MAX Range Within the laser s minimum and maximum wavelength range These values are laser depen dent use the Query Wavelength command to determine your laser s range Units nanometers nm Example Set the wavelength to 1525 nm WAVE 1525 gt OK The wavelength starts changing at the maximum rate until it reaches 1525 nm 6400 Series Lasers Com
15. Output The controller sends aTTL pulse through this BNC connector when a scan hits the specified trigger wavelength 3 Wavelength Trigger B Output The controller sendsaTTL pulse through this BNC connector when a scan hits the specified trigger wavelength 4 Interlock For use with external safety systems the laser will not operate if the interlock circuit is open 5 IEEE 488 Connector for controlling the laser over an EEE 488 GPIB interface 6 Current Modulation Input BNC connector for modulating the laser current amplitude 7 Detector Input BNC connector for monitoring an external instrument through the laser controller s computer interface 8 Power Module The operating voltage is displayed on the power module The module also contains the fuses for the unit NEW FOCUS Inc e aa fd 6400 rev A fm Page 19 Friday June 11 1999 4 41 PM S 9 RS232 Connector for controlling the laser over an RS 232 interface Turning on the Power 1 Makesurethe laser aperture is blocked or attached to an optical fiber that is connected to an appropriate receptacle Use only FC A PC connectorized fiber 2 Beforeturning on the system for the first time check that the AC line voltage indicator on the back of the controller matches the voltage you are using see page 61 3 Turn the power keyswitch on thefront panel clockwise to the 1 position The display will show the laser model number and softwar
16. a table top Use a 1 8 Allen wrench to add or remove the feet or the brackets Starting the Laser for the First Time The following section takes you through the basic steps of starting up and shutting down the laser The controls and functions are described in more detail in the following chapter Figure 3 Front Panel V Telecom Test Laser gt Made in USA Laser Power AC Power o SeanSpeed LJ LJ 1 Make surethe laser aperture is blocked or attached to an opti cal fiber that is connected to an appropriate receptacle Only use fiber with FC A PC connectors 2 Check the voltage setting Check that the power moduleon the back of the laser is set for the proper AC line voltage see page 61 for information on checking and changing the voltage 3 Connect the power cord Attach the power cord to the laser and plug it into a wall outlet 4 Turnonthesystem Turn on theAC Power keyswitch position 1 The system will start up and the system ID will scroll across the display After turning the keyswitch allow the system a minimum of 45 minutes to warm before turning on thelaser diode step 4 Oncethekeyswitch is turned on the system can be operated remotely through the I EEE 488 GPIB or RS 232 ports Refer to the Computer Control
17. al button on the front pang Setting the Laser Power Turn the Power Adjust knob to set the power To prevent damage to the laser diode the factory has limited the maximum current to the laser diode W hen you reach maximum power the controller will engage the current limiter and the power display will start to flash M aximum power is wavdength dependent See page 73 for power specifications Setting the Laser Wavelength Track Mode The 6400 Series laser has two modes track mode and scan mode Whilein track mode you can actively control the tuning motor to operate the laser at a set wavelength 1 Ifthe laser isin scan mode the LED in the Track button is off switch to track mode by pressing the Track button You cannot switch to track mode during ascan Press the Scan button to cancel a scan press it once to finish the current scan press twice to abort the scan immediately 2 Standard tuning resolution is0 01 nm For 0 001 nm resolution press the Scan button whilein track mode The wavelength dis play will shift two decimal places 3 Turn theWavelength Adjust knob to set the wavelength Turn the knob clockwise to increase the wavelength counter clockwise to decrease the wavelength 20 General Operation NEW FOCUS Inc fd 6400 rev A fm Page 21 Friday June 11 1999 4 41 PM Performing Wavelength Scans The 6400 Series laser has two modes track mode and scan mode In scan mode the lase
18. as properly executed e Out of Range if a source value is outside the allowed range e Unknown Command if the command is not recognized Conventions The following pages contain a summary of all available commands followed by detailed definitions for each command The following conventions are used in both the Command Summary and the Command Definitions sections e Thepart of thecommand shown in uppercase represents the short form of the command The commands are case insensitive If the syntax shown is SOURce CURRent then the controller will accept any of the following SSOUR CURR sour curr or sour current It will not accept commands such as SOURC CURR or sour curre e Optional values and portions of syntax are indicated by square brackets e Values to beinput are indicated by angle brackets lt gt and are separated from the command either by aspaceor by a colon as shown in the command syntax e Common EEE 488 commands all begin with an asterisk character the device specific commands all begin with a colon These characters are not optional 6400 Series Lasers Computer Control 31 ao 6400 rev A fm Page 32 Friday June 11 1999 4 41 PM Command Summary System Status and Maintenance Syntax Command Page IDN Identi
19. ay June 11 1999 4 41 PM Getting Started Introduction This section outlines the basic steps needed to start using your 6400 Series laser system including information on unpacking the system and brief set up and starting notes For more detailed information on how to operate the instrument refer to the General Operation chapter beginning on page 13 Unpacking the System Carefully unpack the laser system Compare the contents against the packing slip and inspect them for any signs of damage If parts are missing or you notice any signs of damage such as dented or scratched covers or broken knobs please contact New Focus immediately Save the shipping container and packing material for future shipping needs Check that the power module on the back of the controller is set to the AC line voltage appropriate for your setup see page 61 for information on checking and changing the voltage Setting Up the Laser 6400 Series Lasers The laser is designed to operate in environments from 15 35 C If the laser has been in storage at temperatures outsidetherangeof 10 40 C allow the laser system at least 4 hours to equalize When connecting fiber to the laser use only FC A PC connectorized fiber Getting Started 9 o fd 6400 rev A fm Page 10 Friday June 11 1999 4 41 PM S The laser is shipped with brackets for mounting the system in a rack and with rubber feet for using the system on
20. ay between consecutive scans PAUS Query Pause 48 WAVE STAR lt value gt Set Starting Wavelength 49 WAVE STAR Query Starting Wavelength 49 WAVE STOP lt value gt Set Stopping Wavelength 50 WAVE STOP Query Stopping Wavelength 50 WAVE TRIG A lt value gt Set Trigger A nm 51 WAVE TRIG A Query Trigger A 51 WAVE TRIG B lt value gt Set Trigger B nm 52 WAVE TRIG B Query Trigger B 52 WAVE RAMP lt ON OFF 0 1 gt Enable Disable Wavelength Ramp 53 WAVE RAMP Query Wavelength Ramp Status 53 OUTP SCAN STAR lt value gt Start scanning 54 1 continuous scanning 6400 Series Lasers Computer Control 33 o ao 6400 rev A fm Page 34 Friday June 11 1999 4 41 PM e 34 Computer Control Syntax Command Page OUTP SCAN RESE Reset Scan 54 Finish scan and reset OUTP SCAN ABOR Abort Scan 55 Cancel scan and reset OUTP SCAN STAT Query Scan State 55 Check scan state not scanning run ning a set number of scans continu ously scanning NEW FOCUS Inc 4 0 ao 6400 rev A fm Page 35 Friday June 11 1999 4 41 PM Command Definitions System Status and Maintenance Commands Identification Query Syntax IDN Description Returns the system identification string containing the manufacturer mode number serial number and firmware revision numbers for the laser cavity and controller Example IDN gt NewFocus 6400
21. ble wavelengthsin a compact package By using an external cavity built around a diode laser the 6400 Series laser provides enhanced performance compared to an off the shelf diode laser guaranteeing single mode operation with narrow linewidth and precise wavelength tuning General Theory 6400 Series Lasers The 6400 Series laser iR cavity is based on the a Littman M etcalf design A seerefs on page 59 ki which uses adiffraction J oe Laser Diode Littman M etcalf Laser Cavity 4 US Patent 5 319 668 Collimating Lens Retroreflector ivot grating at grazing Point incidence to provide oT wavelength selectivity Essential to the performance of tunable external cavity diode lasers ECDLs is a high quality anti reflection AR coating on the front facet of the diode The AR coating turns the diode into purely again element A collimating lens directs the output of the diode across a diffraction grating at grazing incidence The retroreflector in the laser cavity reflects the first order diffraction off the grating to provide feedback Dispersion provided by the grating allows only one cavity mode to lase resulting in a very narrow Laser Output Diffraction Grating Principles of Operation 57 e ao 6400 rev A fm Page 58 Friday June 11 1999 4 41 PM P linewidth The specular reflection or zero order diffraction off the grating serves as the output beam of the laser The angle between
22. de push the Power button to turn off the laser when itis notin use the LED on the button will turn off and before shutting down thesystem Turn the keyswitch off position 0 to shut down the entire system To avoid thewarm up period you may want to leave on thesystan power o a Laser radiation emitted from this unit may be harmful A void direct exposure Getting Started 11 ao 6400 rev A fm Page 12 Friday June 11 1999 4 41 PM 12 Getting Started NEW FOCUS Inc ao 6400 rev A fm Page 13 Friday June 11 1999 4 41 PM General Operation Overview The 6400 Series laser is a stable narrow linewidth source of tunable light Useitin track mode to operate it at a set wavelength In scan mode it is capable of fast and extremely linear scans between the start and stop wavelengths that you specify The system can be operated manually using the front panel controls or remotely using one of the computer interfaces What s Inside The 6400 Series laser is an external cavity diode laser ECDL based on the Littman M etcalf design see Principles of Operation on page 57 The laser is designed to provide very accurate and linear wavelength scans Smooth and fast tuning is achieved with a brushless DC motor An optional wavelength ramp ensures linearity by adding 2 nm before and after the specified tuning range to compensates for the motor s start up and slow down times pag
23. diode temperatureis 21 1 C Sense Voltage from Detector Input Syntax SENSe VOLTage LEVel AUXiliary Description Returns the voltage detected at the Detector Input on the back panel of the laser controller N ote This is the only way this value can be read it cannot be read on the front pand The resolution for the Detector Input is 10 bits so the step size is 5 V 21 4 88 mV The response will be rounded to the nearest mV Response xX xxx Range 0 to 5 Units volts V Example SENS VOLT AUX 1 200 The Detector Input sees 1 2 volts 6400 Series Lasers Computer Control 39 ao 6400 rev A fm Page 40 Friday June 11 1999 4 41 PM Power Commands Turn Laser Power On Off Command Syntax OUTPut STATe lt ON OFF 1 0 gt Description Turnsthe laser on or off When turning the laser on the light in the front panel s Laser Power switch will flash for five seconds before the power is turned on Argument OFF ON 0 0r 1 0 or OFF turns thelaser off 1 or ON turns the laser on Example Turn off power to thelaser OUTP 0 gt OK Query Laser Power On Off Syntax OUTPut Description Reads whether or not the laser power is on Response 0 for laser current off and 1 for laser current on Example Determineif the laser current is on or off OUTP gt 1 Thelaser is turned on 40 Computer Control NEW FOCUS Inc gt a 4 0 ao 6400 rev A f
24. e 21 enable or disablethe ramp using the computer interface page 53 The system also provides high resolution when stepping between wavelengths An ultra low noise current source controls the laser s output power A temperature control circuit actively stabilizes the laser cavity temperature for optimal performance the temperature is displayed on the front panel but cannot be adjusted Control the laser s parameters either through the front panel or via the computer interface see Computer Control on page 27 6400 Series Lasers General Operation 13 fd 6400 rev A fm Page 14 Friday June 11 1999 4 41 PM Connecting Fiber to the Laser Use only FC A PC connectorized fiber with the 6400 Series laser We use polarization maintaining fiber inside the laser with the polariza tion aligned parallel to the key on the FC connector The laser output comes to thefront panel through a fiber with an optical isolator of 30 dB preventing optical feedback into the laser cavity Using the Front Panel Controls The 6400 Series laser has two control options local and remote In local mode the front panel provides control of the laser system In remote mode you control the laser over the computer interface I EEE 488 or RS 232 Whenever the 6400 receives a command over the computer interface it automatically deactivates most of thefront panel controls the Local button which restores local control the Laser Power butt
25. e for your system see page 29 If the baud rate is correct then it may be that the serial connector on the laser and on your computer are both set to transmit on pin 2 see page 72 If thisis the case then using anull modem adapter or a null modem cable will solve this problem Wavelength Not Set to the Start Wavelength If the laser is in track mode the Track button should be lit it will not tuneto the start scan wavelength Press the Track button to switch the laser to Scan mode If the laser isin scan mode and the wavelength display does not show that the laser is at the start wavelength it may be because the wavelength ramp is enabled The wavelength ramp is a2 nm offset from the start wavelength that allows the motor enough time to get to 6400 Series Lasers Troubleshooting 65 ao 6400 rev A fm Page 66 Friday June 11 1999 4 41 PM a the specified scan speed before it starts tuning across the designated tuning range Using the ramp results in extremely linear tuning between thestart and stop wavelengths Another 2 nm ramp after the stop wavelength is used to slow down the motor Use the computer interface to enable or disable the ramp See page 53 If the wavelength display does not match the wavelength measured by an external wavelength meter you can recalibrate the laser by adding a wavelength offset using the computer interface See page 44 Scans Won t Start You cannot start a scan if th
26. e laser isin track mode Press the Track button to switch to scan mode Error Codes 66 Troubleshooting The wavelength display will indicate an error code if the controller is unable to perform its proper functions Errors 1 through 7 indicate that a switch is depressed during startup Error 21 may indicate that the safety interlock circuit is open if you are not using the safety interlock feature page 7 check to make sure the jumper on the back of the controller is securely in place If the errors persist contact New Focus Error Description Error 1 Laser Power switch depressed during power up Error 2 Scan button depressed during power up Error 3 Track button depressed during power up Error 4 Multifunction switch depressed during power up Error 5 Scan Speed switch depressed during power up Error 6 Local button depressed during power up Error 7 Multiple stuck buttons during power up Error 21 Interlock error or over power protection NEW FOCUS Inc o oh ao 6400 rev A fm Page 67 Friday June 11 1999 4 41 PM l Errors 11 30 indicate an internal hardware error Switching the laser controller off and then back on can clear some of these errors If the errors persist please contact the New Focus for assistance Error Description Error 11 Microprocessor RAM error Error 12 EPROM revision number mismatch Error 14 Temperature board revision wrong
27. e revision number The keyswitch turns on AC power for the entire laser system including the temperature circuit for the laser diode It does not turn on the power to the laser diode 4 Waitat least 45 minutes after turning on the keyswitch to allow the system to warm up 5 Press theLaser Power button on the controller front pane to allow current to flow to the diode The button will flash during the five second safety delay before the current is activated The button will remain lit while current is flowing to the laser diode 6 Turn the Power Adjust knob to control the amount of current to the laser diode Turning the knob clockwise increases power counter clockwise decreases power If the Power Display begins to flash the power is already at maximum Before turning off the system you should first turn off power to the laser diode by pressing the Laser Power button You can avoid the 45 minute warm up period by leaving the system power keyswitch on when you are not using thelaser 6400 Series Lasers General Operation 19 fd 6400 rev A fm Page 20 Friday June 11 1999 4 41 PM Enabling Local Front Panel Control When the laser receives a command from the computer interface it deactivates all of the front panel controls except the Laser Power and Local buttons This remote control modeis indicated by the Remote LED on thefront panel To return the controller to local front panel control press the Loc
28. ed You should not changethe start or stop wavelengths during a scan 6400 Series Lasers General Operation 21 fd 6400 rev A fm Page 22 Friday June 11 1999 4 41 PM Setting the Scan Speed 1 Display the current scan speed by pushing up the Scan Speed switch The Wavelength display will changeto show the current scan speed 2 Whilestill holding theswitch up turn the Wavelength Adjust knob to change the scan speed 3 Reeasethe switch If you changethe scan speed during a scan the new speed will not take effect until thecurrent scan is canceled or finished and a new scan is started Setting Output Triggers As the laser scans itis capable of sending TTL trigger signals The signals are sent through thetwo back panel BNC connectors Output Trigger A and Output Trigger B 1 To set trigger A hold down the Scan Speed switch and push up the Start Stop A switch while turning the Wavelength Adjust knob 2 To set trigger B hold down both the Scan Speed switch and the Start Stop A switch while turning the Wavelength Adjust knob 3 Releasethe switches The rising edge of the output signal corresponds with the trigger wavelength The trigger jitter of the rising edgeis about 1 ms The pulse width can vary but is usually around 1 ms Starting a Scan From the front panel you can set the laser to perform a single scan or to continuously scan 1 If thelaser isin track mode press the Track button to switc
29. ee Q uery Wavelength page 44 Units nanometers nm Example Set scans to start at 1530 nm WAVE STAR 1530 gt OK Query Starting Wavelength Syntax SOURce WAVElength STARt Description Queries the starting wavelength for scans N ote If the wavdength ramp is enabled scans will start 2 nm beforethis wavdength Seepage 21 for moreon theramp or page 53 for information on enabling or disabling the ramp Response X XXX Units nanometers nm Example WAVE STAR 1530 000 Scans will start at 1530 nm or at 1528 nm if the ramp is enabled 6400 Series Lasers Computer Control 49 gt 4 ao 6400 rev A fm Page 50 Friday June 11 1999 4 41 PM Set Stop Wavelength for Wavelength Scans Syntax SOURce WAVElength STOP lt val gt Description Sets the ending wavelength for wavelength scans N ote If the wavdength ramp is enabled the laser will stop scanning 2 nm after the stop wavelength See page 21 for moreon the ramp or page 53 for information on enabling or disabling the ramp Argument X XXX Range Thevalue must be greater than the start wavelength and must be within the laser s operat ing range Theminimum and maximum values are laser dependent See Q uery Wavelength above Units nanometers nm Example Set scans to start at 1530 nm WAVE STAR 1530 gt OK Query Stopping Wavelength Syntax SOURce WAVELength STOP Descript
30. ev A fm Page 72 Friday June 11 1999 4 41 PM Appendix B RS 232 Connector Wiring The RS 232 connector on the back of the laser controller is a standard female 9 pin D connector RS 232 ports can be configured for operation in DTE or DCE mode The RS 232 port on the 6400 Series laser is configured as a DCE port This means the laser controller receives data on pin 2 and transmits data on pin 3 see below If you have trouble communicating with the laser over the RS 232 port you may need to use a null modem adapter or cable Figure 10 RS 232 6 789 ore Female 9 Pin D Pin Name Description Connector 1 Not Connected OOOO me oe a 2 TX Serial Transmit Line 3 Rx Serial Receive Line ae A 4 Not Connected Grai Hes 5 Ground Digital Ground Line 6 9 Not Connected 72 Appendices gt NEW FOCUS Inc ao 6400 rev A fm Page 73 Friday June 11 1999 4 41 PM Appendix C Specifications Specification Model 6428 Tuning Range 1500 1575 Output Power gt 6dBm 1520 1570 nm gt 0 dBm 1500 1575 nm Mode Hop Performance mode hop free from 1520 1570 nm Side Mode Suppression Ratio gt 40 dBc relative to central mode gt 45 dBc typical Tuning Speed 1 100 nm s Wavelength Resolution 1pm Absolute Wavelength Accuracy 0 2 nm over warranty period Computer Interface IEEE GPIB and RS 232 6400 Series Lasers Appendices 73
31. fd 6400 rev A fm Page 1 Friday June 11 1999 4 41 PM USER S GUIDE 6400 Series Lasers External Cavity Tunable Diode Lasers U S Patent 5 319 668 amp Other Patents Pending Useof controls or adjustments or performance of procedures other than those specified herein may result in hazardous CAUTION radiation exposure v NEW FOCUS Inc 2630 Walsh Ave Santa Clara CA 95051 0905 USA phone 408 980 8088 e fax 408 980 8883 e mail contact newfocus com www newfocus com aa ao S 6400 rev A fm Page 2 Friday June 11 1999 4 41 PM Warranty New Focus Inc guarantees its lasers to be free of material and workmanship defects for one year from the date of shipment or 3 000 hours of operation whichever comes first This warranty isin lieu of all other guarantees expressed or implied and does not cover incidental or consequential loss Products described in this document are covered by U S Patent 5 319 668 and patents pending Copyright 1999 New Focus Inc All rights reserved The v symbol and NEW FOCUS Inc are registered trademarks of New Focus Inc Littelfuse and Slo Blo are registered trademarks of Littelfuse Inc Document Number 640046 Rev A gt 4 ao 6400 rev A fm Page 3 Friday June 11 1999 4 41 PM Contents User Safety 5 INtrOdUCHON ia eiasth ai iiai tien aces nian eeetladenss 5 Laser Safety scott wisi pa Baier eaii E S 5 Using the Safety Inte
32. fication Query 35 OPC Operation Complete Query 35 OUTP SCAN MAIN Start Maintenance Cycle 36 SYST MCON lt INT EXT gt Set Control Mode Remote Local 37 SENS WAVE Sense Wavelength nm 38 SENS CURR DIOD Sense Level of Current mA 38 SENS TEMP LASF Sense Temperature C 39 SENS VOLT AUX Sense Voltage from Detector Input 39 OUTP SCAN STAT Scan State 55 Check scan state none set con tinuous Power Commands Syntax Command Page OUTP lt on off gt Tum Laser Power On Off 40 OUTP Query Laser Power On Off 40 POW lt value gt Set Laser Output Power dBm 41 POW Query Laser Power Setpoint 41 POW TRIM lt value gt Set Power Trim 42 POW TRIM Read Power Trim 42 32 eComputer Control NEW FOCUS Inc ao 6400 rev A fm Page 33 Friday June 11 1999 4 41 PM Wavelength Commands Syntax Command Page WAVE lt value MIN MAX gt Set Wavelength also switches to track 43 mode nm WAVE lt MIN MAX gt Query Wavelength 44 WAVE OFFS lt value gt Set Wavelength Offset nm 44 WAVE OFFS Query Wavelength Offset 45 Scan Commands Syntax Command Page OUTP TRAC OFF Switch to Scan Mode 46 WAVE SLEW lt value MIN MAX gt Set Scan Speed nm sec 47 WAVE SLEW lt MIN MAX gt Query Scan Speed 47 PAUS lt value gt Set Pause ms 48 Set del
33. h the laser to scan mode the light in the track button should be off 2 Torun asinglescan press the Scan button once To repeatedly run scans push up the Start Stop switch and press the Scan button 22 General Operation NEW FOCUS Inc fd 6400 rev A fm Page 23 Friday June 11 1999 4 41 PM S 3 After the laser finishes a scan it returns to the start wavelength minus the ramp see Using the Wavelength Ramp on page 21 You can set the laser to run a specific number of scans using computer control see page 54 Using a Trigger to Begin a Scan There is aTrigger input jack with an SM B type connector under the Start Stop A switch A TTL signal sent to the laser through this connector is equivalent to depressing and releasing the Scan button The actual trigger happens on the falling edge Cancelling a Scan To stop an ongoing scan press the Scan button The laser will finish the current scan and return to the Start wavelength To abort a scan press the Scan button twice The laser will immediately stop the current scan and return to the Start wavelength Using a Trigger to End a Scan There is a Trigger input jack with an SM B type connector under the Start Stop A switch A TTL signal sent to the laser through this connector is equivalent to depressing and releasing the Scan button The actual trigger happens on the falling edge Scan Maintenance If you repeat ascan for along period of time the syste
34. h your Computer Control 27 o fd 6400 rev A fm Page 28 Friday June 11 1999 4 41 PM computer Configuration is required to talk to an instrument at a given address and to issue commands to it from the programming language The IEEE connector on the back of the laser controller allows for remote operation through a standard IEEE 488 GPIB cable The connector is a standard female 24 pin IEEE 488 connector for use with a standard shielded EEE 488 cable In order to function properly you must assign a device address to the laser controller that is unique from all the other IEEE 488 components attached to your computer See Programming for the 6400 Series Laser on page 30 for more information on using the IEEE interface Setting the Device Address 1 Onthefront panel press and hold the Local button and hold up the Scan Speed switch 2 Turn theWavelength Adjust knob until the desired address number appears in the Wavelength display The address can be from 1 to 31 3 Reeasethe Local button and the Scan Speed switch Using the RS 232 Interface The RS 232 9 pin connector on the back of the controller allows for remote operation through astandard 9 pin RS 232 cable see page 72 To usethe RS 232 port attach a standard shielded RS 232 cable to the connector RS 232 ports can beconfigured for operation in D TE or DCE mode TheR S 232 port on the 6400 Series laser is configured as a D CE port Th
35. he laser controlling the output power The temperature control regulates the laser cavity temperature providing a stable output wavelength The laser wavelength is also affected by the current through the diode Changing the diode current affects the refractive index of the diode lasers and therefore thelaser cavity length The magnitude of the effect is diode dependent but is typically 25 150 MHz mA 58 Principles of Operation NEW FOCUS Inc ao 6400 rev A fm Page 59 Friday June 11 1999 4 41 PM References T Day F Luecke and M Brownell Continuously tunable diode lasers Lasers and Optronics pages 15 17 June 1993 K C Harvey and C J Myatt External cavity diode laser using a grazing incidence diffraction grating O ptics Letters vol 16 pages 910 912 1991 M G Littman and H J Metcalf Spectrally narrow pulsed dye laser without beam expander Applied Optics vol 17 pages 2224 2227 1978 M G Littman Single mode operation of grazing incidence pulsed dye laser O ptics Letters vol 3 pages 138 140 1978 M G Littman Single mode pulsed tunable dye laser Applied Optics vol 23 pages 4465 4468 1984 K Liu and M G Littman Novel geometry for single mode scanning of tunable lasers Optics Letters vol 6 pages 117 118 1981 6400 Series Lasers Principles of Operation 59 ao 6400 rev A fm Page 60 Friday June 11 1999 4 41 PM 60
36. inations To access many of the laser s features you will need to use several 6400 Series Lasers front panei controls at the same time The following table summarizes these combinations View Set start wavelength for scans Local Button Track Button Scan Button Scan Speed Switch Wave length Switch Start Yy Stop Wave length Knob View Set stop wavelength for scans Start Stop A View Set scanning speed Y Scan Speed Start Yy Start continuous scan Scan Stop Start View Set wavelength R a Y Q for Trigger A output Scan Speed era Start View Set wavelength A Ae B for Trigger B output Scan Speed agar Set GPIB address Loca Scan Speed Wavelength Set RS 232 baud rate R Scan Speed o General Operation 17 e EL fd 6400 rev A fm Page 18 Friday June 11 1999 4 41 PM S E a Back Panel and Tunable Laser Cavity Connections Figure 5 Controller back panel 18 General Operation There are several input and output connectors on the back of the laser controller 123 4 5 6 7 8 9 1 Laser Sync Output The controller sends a TTL signal out through this BNC connector when thelaser is scanning from the start to the stop wavelength 2 Wavelength Trigger A
37. ion Queries the ending wavelength for scans N ote If the wavdength ramp is enabled the laser will stop scanning 2 nm after the stop wavelength See page 21 for moreon the ramp or page 53 for information on enabling or disabling the ramp Response X XXX Units nanometers nm Example WAVE STOP 1560 000 Scans will end at 1560 nm or at 1562 if the ramp is enabled 50 Computer Control NEW FOCUS Inc ao 6400 rev A fm Page 51 Friday June 11 1999 4 41 PM E e 6400 Series Lasers Set Trigger A Syntax Description Argument Example Query Trigger A Syntax Description Response Example SOURce WAV o Elength TRIGger A lt value gt Sets a wavelength that will send a TTL output pulse to the controller s Trigger A output during a wavelength scan Therising edge of the pulse corresponds with the trigger wavelength Thetrigger jitter is about 1 ms and the pulse width is also about 1 ms X XXX Range The value sh stop wavelengths Units nanometers Send a trigger pulse 1552 655 nm ould be between the laser s start and nm when thescan crosses WAVE TRIG A 1552 655 gt OK SOURce WAV Elength TRIGger A Queries thetrigger A wavelength X XXX Units nanometers WAVE TRIG A 1552 655 Scans will trigger a nm pulse at 1552 655 nm Computer Control 51 ao 6400 rev A fm Page 52 Friday Ju
38. is means thelaser controller receives data on pin 2 and transmits data on pin 3 seepage 72 If you havetrouble communicating with thelaser over theR S 232 port you may need to usea null modem adapter or cable To communicate with the laser set your computer to 8 bit no parity 1 stop xon or xoff The controller can support baud rates between 300 and 19 200 bps Use the following steps to set the controller s baud rate 28 Computer Control NEW FOCUS Inc fd 6400 rev A fm Page 29 Friday June 11 1999 4 41 PM ig See Programming for the 6400 Series Laser on page 30 for more information on using the RS 232 interface Setting the Baud Rate for RS 232 The RS 232 interface works at baud rates of 300 1200 2400 4800 9600 or 19200 1 Onthefront panel press and hold the Local button and hold down the Scan Speed switch 2 Turn theWavelength Adjust knob to change the baud rate setting 3 Releasethe Local button and the Scan Speed switch Restoring Local Front Panel Control Commands which alter the state of the laser controller will switch the laser into remote mode and disable most of the front panel controls This remote control mode is indicated by the Remote LED on the front panel of the laser Commands which do not alter thestate of thelaser will not affect thecontrol mode For example you can usethe computer to monitor all laser operating parameters while the operator manually changes
39. m s moving parts are restricted to a small range of motion which could lead to uneven wear You can initiate full motion of all moving parts by turning the power keyswitch off and then back on You can also initiate the same motion using the Start Maintenance Cycle command via computer control see page 36 Werecommend running this maintenance routine once for every 30 000 scans about once every 24 hours of continuous scanning 6400 Series Lasers General Operation 23 fd 6400 rev A fm Page 24 Friday June 11 1999 4 41 PM Laser Sync Output A Laser Sync Output is provided to signal when the laser is scanning from the start to the stop wavelength In scan mode this output generates a TTL signal as the laser scans from the start to the stop wavelength No signal is produced during the wavelength ramps or as the laser resets from the stop wavelength back to the start wavelength Modulating the Laser Output Modulate the laser current amplitude using an externally generated low level signal Connect the line for the input signal to the Current Modulation connector on the back of the controller M ake surethe signal conforms to the following specifications Since changes in the current affect the laser frequency modulating the current will also create some fine frequency modulation dueto changes in the index of refraction of the laser gain medium The degree to which this affects the wavelength is laser dependent b
40. m Page 41 Friday June 11 1999 4 41 PM Set Laser Output Power Syntax SOURce POWer LEVel lt value gt Description Sets the power level This command will not turn on power to the laser Argument XeoX Range 3 0 to 6 9 Units dBm N ote Power is wavdength dependent You will not be able to achievefull power at all wavelengths See specifications on page 73 Example Set the laser power to 2 5 dBm POW 2 5 gt OK Query Laser Power Setpoint Syntax SOURce POWer LEVel Description Queries the laser power setpoint Response XX Range 3 0 to 6 9 dBm Example SOUR POW gt 2 8 Laser output is set to 2 8 dBm 6400 Series Lasers Computer Control 41 gt ao 6400 rev A fm Page 42 Friday June 11 1999 4 41 PM Set Power Trim Syntax SOURce POWer TRIM lt value gt Description Allowsyou to calibratethe output power to an exter nal power meter You can alter the output power by 15 from factory settings N ote Thelaser power must be off to change thetrim Argument X XX Range 0 85 1 15 This valueis a multiplier to the photodetector signal The value 0 85 corresponds to 0 7 dB and 1 15 cor responds to 0 6 dB To calculate a value based on a desired dB correction use value 10 8 rrection 10 Example The power level shown on thefront pand is off by 10 when measured by an external power meter so you want to increase the output power by 10 POW TRI
41. mple WAVE SLEW gt 22 The laser will scan at 22 nm s 6400 Series Lasers Computer Control 47 gt ao 6400 rev A fm Page 48 Friday June 11 1999 4 41 PM Set Pause Syntax SOURce WAVElength PAUSe lt val gt Description Sets a delay between consecutive scans The laser scans from the start to the stop wavelength at the set scan rate resets to the start wavelength and then pauses before performing the next scan Argument x Units milliseconds ms Example Set a 1 5 second pause between consecutive scans PAUS 1500 OK Query Pause Syntax SOURce WAVElength PAUSe Description Checks the delay between consecutive scans Response XXX Units milliseconds ms Example PAUS 800 The laser will pause for 800 ms between scans 48 eComputer Control NEW FOCUS Inc ao 6400 rev A fm Page 49 Friday June 11 1999 4 41 PM l z Set Starting Wavelength for Wavelength Scans Syntax SOURce WAVElength STARt lt val gt Description Sets the starting wavelength for wavelength scans N ote If the wavdength ramp is enabled the laser will start scanning 2 nm beforethe start wavdength See page 21 for moreon the ramp or page 53 for information on enabling or disabling the ramp Argument X XXX Range The value must be less than the stop wave length and must be within the laser s operating range Theminimum and maximum values are laser dependent S
42. n use to get the attention of the controller before starting a command entry and end each command with a carriage return lt cr gt e A command isnot parsed until anew line character is received RS 232 or a hardware EOI is detected IEEE 488 e Numbers may contain at most 15 characters The number 1550 will be read correctly but the number 00000000000001550 will be read as 15 e Commands that expect integer values will truncate after any decimal point in the input For example if acommand is issued to run 11 76 scans the laser will run 11 scans e Only one command can beissued per line For example if the controller receives WAVE 1550 IDN it will changethe wavelength to 1550 but the Identification Query will be ignored e Laser controller responses are sent differently depending on the interface you are using IEEE 488 responses are written into the output buffer afirst in first out FIFO buffer with a capacity for 5 outgoing messages You will need to send a separate command to read the response from the buffer RS 232 responses are sent immediately and can be processed or ignored Thecontroller doesnot echo the command 30 eComputer Control NEW FOCUS Inc ao 6400 rev A fm Page 31 Friday June 11 1999 4 41 PM l e If sent an action command such as change the power or set the wavdength the controller will return oneof the following responses OK if the command w
43. ne 11 1999 4 41 PM Set Trigger B Syntax SOURce WAVElength TRIGger B lt value gt Description Sets a wavelength that will send a TTL output pulse to the controller s Trigger B output during a wavelength scan Therising edge of the pulse corresponds with the trigger wavelength The trigger jitter is about 1 ms and the pulse width is also about 1 ms Argument X XXX Range The value should be between the laser s start and stop wavelengths Units nanometers nm Example Send a trigger pulse when the scan crosses 1559 25 nm WAVE TRIG B 1559 25 gt OK Query Trigger B Syntax SOURce WAVELength TRIGger B Description Queries the trigger B wavelength Response X XXX Units nanometers nm Example WAVE TRIG B gt 1559 250 Scans will trigger a pulse at 1559 25 nm 52 Computer Control NEW FOCUS Inc ao 6400 rev A fm Page 53 Friday June 11 1999 4 41 PM Enable Disable Wavelength Ramp Syntax SOURce WAVElength RAMPenable lt ON OFF 0 1 gt Description Enables or disables a 2 nm wavelength ramp at the beginning and end of a scan The ramp enables the laser to scan at a constant rate between the specified start and stop wavelengths The ramp is used at the beginning of a scan to accelerate the tuning motor to the desired scan speed The laser then tunes at a constant rate through the stop wavelength and uses the ramp to decelerate to a stop Argument 0 1 ON O
44. on and the power keyswitch all remain active For information on using computer control see page 27 Thecontrols on the front panel Figure 4 allow you to read and set the laser power wavelength start and stop wavelengths for scans scanning speed and computer interface parameters Figure 4 4 5 6 7 Controller front panel Telecom4fest Laser 14 General Operation NEW FOCUS Inc ao 6400 rev A fm Page 15 Friday June 11 1999 4 41 PM a 6400 Series Lasers AC Power Keyswitch Controls AC power to the entire laser sys tem including the temperature control circuit Power is not sup plied to the laser diode until the Laser Power button is activated Power Indicator This indicator is lit when the system power is on To check if power is being supplied to the laser diode check the indicator light in the Laser Power button Local Button Returns the controller to local front panel control when the driver is in remote computer control mode Laser Power Button Turns on and off current to the laser diode W hen the laser power is on this button will remain lit Addressed Indicator This indicator is lit whenever the controller is communicating over the computer interface see the
45. puter Control 43 q ihe ao 6400 rev A fm Page 44 Friday June 11 1999 4 41 PM Query Wavelength Syntax SOURce WAVElength MIN MAX Description Queries the wavelength setpoint or the minimum or maximum available wavelengths Response X XXX Units nanometers nm Example WAVE 1525 000 The wavelength is set to 1525 nm WAVE MIN 1500 The shortest wavelength possible is 1500 nm Set Wavelength Offset Syntax SOURce WAVElength OFFSet lt val gt Description Allows you to recalibrate the laser to an external wavelength meter This value is reset to factory default if the system power keyswitch is shut off N ote You need to initiate a scan or a track mode operation to activate the offset Argument X XXX Range 2 5 Units nanometers nm Example Set the absolute wavelength 0 02 nm lower than before WAVE OFFS 0 02 gt OK You will not noticea difference without using an external wavelength meter 44 Computer Control NEW FOCUS Inc ao 6400 rev A fm Page 45 Friday June 11 1999 4 41 PM Query Wavelength Offset Syntax SOURce WAVElength OFFSet Description Checks the value of the wavelength offset Theunits arein nanometers Response X XXX Units nanometers nm Example WAVE OFFS 0 030 The wavelength has been offset by 0 030 nm from the factory calibrated setting 6400 Series Lasers Computer Con
46. r OFF 1 or ON enables the ramp 0 or OFF disables it Example Enable the wavelength ramp WAVE RAMP 1 gt OK Query Wavelength Ramp Status Syntax SOURce WAVELength RAMPenable Description Checks thestatus of the 2 nm wavelength ramp at the beginning and end of ascan Response 1 for enabled o for disabled Example WAVE RAMP gt 1 Theramp is enabled 6400 Series Lasers Computer Control 53 q e ao 6400 rev A fm Page 54 Friday June 11 1999 4 41 PM Start Scanning Syntax OUTPut SCAN STARt lt value gt Description Runs the specified number of wavelength scans The laser scans from the start to the stop wave length at the specified scan speed and then returns to the start wavelength at maximum speed If no valueis entered the laser will scan once and remain tuned to the ending wavelength plus 2 nm if the ramp is enabled The OPC command will return 0 until the stop wavelength is reached on the last scan Argument x or no argument Range 1 or any positive integer A value of 1 will repeat scans until scanning is can celled or aborted Example Run 25 wavelength scans OUTP SCAN STAR 25 gt OK Reset Scan Syntax OUTPut SCAN RESEt Description Resets the laser to ready mode If a scan isin progress it will be allowed to finish the current scan before the laser is reset The Operation Complete Query will return 0 until the
47. r continuously tunes from one wavelength to another You control the start and stop wavelengths the scan speed and the number of scans The system always scans from low to high wavelengths You can also set the laser to send trigger signals at specified wavelength see Setting Output Triggers on page 22 Using the Wavelength Ramp In order to obtain extremely linear tuning the laser can add 2 nm ramps to the beginning and end of the scan range which allow the motor to get up to speed before the specified start wavelength and to slow down after the specified ending wavelength For example if the ramp is enabled and you set a scan to run from 1500 1550 nm the laser will actually start at 1498 nm and run through 1552 nm Use computer control to enable or disable the ramp see page 53 Setting the Start and Stop Wavelengths 1 Display thecurrent start wavelength by pushing up the Start Stop switch 2 Whilestill holding theswitch up turn the Wavelength Adjust knob to change the start wavelength 3 Push theStart Stop A switch down to display the current stop wavelength 4 Whilestill holding the switch down turn the Wavelength Adjust knob to change thestop wavelength The stop wavelength must be larger than the start wavelength 5 Reeasethe switch 6 If thelaser isin track mode switch to scan mode by pressing the Track button The laser will then tune to the start wavelength minus the 2 nm ramp if it is enabl
48. rlock ccc ee eee eee 7 Getting Started 9 ATFOOQUCH ON weitere ree reat eat aa tg isis 9 Unpacking the System ce cee eee e eee ees 9 Setting Up the Laser ccc eee ee eee e eee ees 9 Starting the Laser for the First Time 008 10 General Operation 13 OVEINVIOW fives cieiiielel tit dacveiss ales ace iies 13 What sInside uuni 13 Using the Front Panel Controls sasssa 14 Control Combinations cece eee eee ee 17 Back Panel and Tunable Laser Cavity Connections 18 Turningon the POWE aaaeeeaa 19 Enabling Local Front Panel Control 20 Setting the Laser POWer 0 06 cece eee eee eee ee 20 Setting the Laser Wavelength Track Mode 20 Performing Wavelength Scans s usec 21 Laser Sync Output vacicca deere esse ered betes 24 Modulating the Laser Output 0005 24 Reading an Input Signal cece eee 25 6400 Series Lasers Contents 3 ao 6400 rev A fm Page 4 Friday June 11 1999 4 41 PM Computer Control 27 INGFOdUCHON ciacd cates apaied Ged owen as 27 Using the IEEE 488 Interface 0ee 27 Using the RS 232 Interface ceeee eee 28 Restoring Local Front Panel Control 29 Understanding the Command Types 29 Programming for the 6400 Series Laser 30 CONVENTIONS 25 s esseer sser reenn rerna 31 Command SUMMary 06 c cece eee eee 32 Command Definitions
49. set operating wavelength and scan mode Wavelength Adjust Knob Adjusts the wavelength while in track mode Sets other parameters when other buttons or switches are depressed see Control Combinations on page 17 Scan Button Starts and stops a wavelength scan For continuous scanning hold up the Start Stop switch before pressing Scan Pressing the button twice aborts a scan For more on scanning see page 21 If pressed while in track mode allows high resolution tuning 0 001 nm and shifts the wavelength display by two decimal places Start Stop Sw itch Display or se the start and stop wavelengths for wavelength scans In the down position it will also change the temperature display to show the motor temperature Trigger SMB connector for TTL input pulses Each input pulsehas the same effect as pressing and releasing the Scan button The falling edge of the pulse initiates the action Laser O utput Connector for FC A PC connectorized single mode fiber M ake surethe laser output is blocked or attached to an optical fiber and the fiber is connected to an appropriate receptacle on the other end Weuse polarization maintaining fiber in our 6400 Series lasers The polarization is aligned parallel to the key on the FC connector Power Adjust Knob Adjusts the laser s output power NEW FOCUS Inc o d ao 6400 rev A fm Page 17 Friday June 11 1999 4 41 PM e Control Comb
50. start wavelength is reached Example Completethe current scan and return to ready modeat the start wavelength OUTP SCAN RESE OK 54 Computer Control NEW FOCUS Inc ao 6400 rev A fm Page 55 Friday June 11 1999 4 41 PM Abort Scan Syntax OUTPut SCAN ABORt Description Immediately cancels the current scan and sets the laser to the start wavelength This is similar to the Reset Scan command except that the current scan is not completed Example Cancel the current scan and reset immediately to thestart wavelength OUTP SCAN ABOR gt OK Query Scan State Syntax OUTPut SCAN STATe Description Reads the scan state of the laser Response Nz 0 indicates the laser isin scan mode and waiting at the start wavelength An integer indicates the laser is in the middle of per forming that fixed number of scans 1 indicates the laser is performing continuous scans 2 indicates the laser isin track mode Example OUTP SCAN STAT gt 0 Thelaser is at the start wavelength and ready to scan 6400 Series Lasers Computer Control 55 q e ao 6400 rev A fm Page 56 Friday June 11 1999 4 41 PM 56 Computer Control NEW FOCUS Inc fd 6400 rev A fm Page 57 Friday June 11 1999 4 41 PM a Principles of Operation Overview Traditional diode laser technology provides high reliability high electrical efficiency and a wide range of availa
51. surethe proper fuses are installed in your system The power entry module requires two 5x20 mm slow blow fuses such as Littelfuse s Slo Blo 239 series one for the hot line and the other for the neutral line Replacement fuses should be as follows 62 Changing the AC Voltage Selection e NEW FOCUS Inc ao 6400 rev A fm Page 63 Friday June 11 1999 4 41 PM AC Take AC Voltage Fuse Rating Slo Blo Fuse their recom 100 VAC 2 0A 239 002 men geese 120V AC 20A 239 002 220 VAC 10A 239 001 240 V AC 10A 239 001 7 Closethe power module cover 8 Verify the proper voltage is showing through the module window 9 Reconnect theAC power cord 6400 Series Lasers Changing the AC Voltage Selection 63 ao 6400 rev A fm Page 64 Friday June 11 1999 4 41 PM 64 Changing the AC Voltage Selection NEW FOCUS Inc ao 6400 rev A fm Page 65 Friday June 11 1999 4 41 PM Troubleshooting Front Panel Controls Won t Work If thefront panel controls aren t working the laser may bein remote computer control mode Press the Local button on the front panel to restore local control Computer Control Doesn t Work If you are using the IEEE GPIB interface make sure the laser is set to the same device address as your software is requesting see page 28 If you are using the RS 232 interface make sure the laser system is set to the correct baud rat
52. trol 45 ao 6400 rev A fm Page 46 Friday June 11 1999 4 41 PM Scan Commands Switch to Scan Mode Syntax OUTPut TRACk OFF Description Switches the laser into scan mode and sets the wavelength to the start wavelength so it is ready to start ascan N ote If the wavdength ramp is enabled the laser will beset to the start wavdength minus the2 nm ramp Seepage 21 for moreon the ramp or page 53 for information on enabling or disabling the ramp Example Turn off track mode and set the laser to the start wavelength in scan mode t OUTP TRAC OFF gt OK 46 eComputer Control NEW FOCUS Inc ao 6400 rev A fm Page 47 Friday June 11 1999 4 41 PM E e Set Scan Speed Syntax SOURce WAVElength SLEWrate lt val MIN MAX gt Description Sets the slew rate the speed at which the laser tunes between the start and stop wavelengths This value only affects the speed at which the motor tunes from the start to stop wavelength W hen resetting to the start wave length or tuning to a specific wavelength in track mode the motor moves at the maximum rate Argument x MIN Of MAX Range 1 100 Units nanometers per second nm s Example Set the scan speed to 15 nm s WAVE SLEW 15 gt OK Query Scan Speed Syntax SOURce WAVElength SLEWrate lt MIN MAX gt Description Checks the set value of the scan speed Response XXX Units nanometers per second nm s Exa
53. ty labels examples are shown on page 6 e To completely shut off electrical power to theunit turn off the keyswitch The Power button on the front panel only controls power to the laser diode even when power to the diodeis off power is still supplied to other system components e Donotopen the laser system There are no user serviceable parts inside the unit D iode laser power at the wavelengths shown in thefollowing table could be accessibleinsidethe laser U nauthorized opening of the laser Contents 5 o fd 6400 rev A fm Page 6 Friday June 11 1999 4 41 PM will void the warranty and may result in burns dectric shock misalignment of the laser cavity and or irreparable damage to theinternal components The following table shows the wavelength range and the maximum internal power accessible inside the laser Model Wavelength Range Max Power 6428 1450 1650 nm These values represent maximum values for the laser diode The actual wavdength range will beless and the output power will only bea fraction of themaximum internal diode power shown here See page 73 for operating specifications Label Identification The following figures show the locations of the various warning labels used with this product Please be aware of them and use caution when working with the laser Figure 1 Danger label Safety labels on the front of the laser Aperture label INVISIBLE LASER RADIATION AVOID AVOID
54. ut it isin the range of 25 40 MHz mA Current Modulation Input Guidelines DC coupled Connector Type BNC Max Voltage 10V Input Frequency Range 5 kHz 1 MHz Impedance 5kQ Modulation 0 2 mA V TheD C coupled Current M odulation Input is N O T current limited To prevent UA damage to thelaser diodeD O NOT modulate the current above 10 V The front panel current readout does not reflect the modulation input You can calculate the actual current by adding the current shown on thefront pane display to the modulation input 24 General Operation NEW FOCUS Inc ao 6400 rev A fm Page 25 Friday June 11 1999 4 41 PM l Reading an Input Signal You can monitor an input signal using the DC coupled Detector Input connector on the back of the laser controller Theinput is connected to a 10 bit analog to digital converter This general purpose input allows you to collect data from another instrument such as a photodetector during a wavelength scan Connect the line for the input signal to the BNC connector on the back of the laser controller M ake sure the signal conforms to the following specifications Detector Input Guidelines Connector Type BNC Voltage Range OVto 5V Input Frequency DC 10 kHz Impedance 51kQ 6400 Series Lasers General Operation 25 ao 6400 rev A fm Page 26 Friday June 11 1999 4 41 PM 26 General Operation NEW FOCUS Inc ao
55. y 30 000 scans or every 24 hours of con tinuous scanning is sufficient N ote Turn off power to the diode before initiating this command Example OUTP SCAN MAIN gt OK NEW FOCUS Inc a 4 0 ao 6400 rev A fm Page 37 Friday June 11 1999 4 41 PM z e 6400 Series Lasers Set Control Mode Local Remote Syntax Description Argument Example SYSTem MCONtrol lt INT EXT gt Puts controller into Remote mode using the inter nal DACs or Local Mode using the external front panel controls INT OF EXT INT sets the laser to usetheinternal DACs and gives you remote control via the computer interface The laser will usethe current power setpoint when it switches to remote control The front pandi dis plays will change as sensed Target values can differ by up to 3 due to component variations EXT returns control to the external front pand controls Thelaser power will return to the last level set from the front panel Note that in Remote Mode the front pand potenti ometers are ignored but they are still active If a potentiometer is changed to an extreme setting and the controller isthen switched back to external con trol the corresponding parameter will then move to the extreme setting SYST MCON INT OK Thelaser switches to remote mode and thefront panel s remote light turns on Computer Control 37 e 0 ao 6400 rev A fm Page 38 Friday June 11 19
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