LTBIS_Manual_Rev01 - Fibotec Fiberoptics GmbH
Contents
1. 0 384A tec Maximum TEC 1 0 mA Bit DOOh 768d current 768Bit x 2 441 mA Bit 1 874A ntc NTC voltage 1 0 mV Bit 300h 768d 7 68Bit x 1 0 mV Bit 0 768V 12511 10k 2 274 100k ee i regulator GND Fig 7 Schematic of the lasers NTC resistor voltage measurement circuit 3 7 Retrieving actual laser data The four commands set chX maxYYY powYYY ntcYYY tecYYY are used to preselect the laser s parameters as target data The corresponding get commands only retrieve the values YYY being sent Actual parameters of the lasers are retrieved by different commands see chapter 3 4 4 which control the measurement of these and include an A D conversion All these commands give a three digit result YYY in hexadecimal numbers but of different unit depending on the data see below All A D converters of the system are adjusted to a sensitivity of 2 441 units Bit with unit mA pA mV 0 1 C corresponding to the following table All measurement results are given in complements on two in order to allow for negative results LTBIS RevO1 Range of values YYY in complements on two max 0 1 Max Table of units for calculating retrieved laser status data Command Parameter A D Example Sensitivity curl Laser diode 2 441 mA Bit 300h 768d current 768Bit x 2 441MA Bit 1 874A curl TEC current 2 441 mA Bit VoIL Laser diode 2 441 mV Bit 300h 768d voltage 768Bit x 22. the following steps e Loose four front panel screws of the plug in module Fig 3 10 11 12 13 e Two front panel screws need to be kept in place e Carefully pull the plug in module out of the 19 case e Disconnect all laser fiber connections from rear of front panel adapter Fig 5 16 e Unclamp the two wings of the laser socket Fig 4 5 6 e Remove the four plastic screws holding the laser package Fig 4 1 2 3 4 e The laser can now be removed Don tremove the thermal pad below the laser e Areplacement laser can be inserted Assemble in reverse order LTBIS RevO1 Caution When positioning a laser butterfly package into the socket make sure that the contact pins are in the appropriate slots in the socket before closing the wings Caution Don t remove or properly replace the thermally conducting and electrically isolating pad below the laser 2 3 Computer control RS232 interface The interface is a three wire type Tx RX gnd Any ASCII terminal program e g Windows OS Hyperterminal can be used for line oriented communication Serial Interface initial settings 115200 baud 8N1 no handshake 3 Operation 3 1 Power up After switching the mains switch on the rear panel to 1 two green front panel LEDs Power on the master module indicate proper operation of the internal power supplies A blue LED Interlock indicates that the interlock safety circuit sub D connector rear panel is
3. 1597 IDO Fibotec Fiberoptics GmbH 25 09 2014 Herpfer StraBe 40 98617 Meiningen Tel 49 0 3693 8813 200 Fax 49 0 3693 8813 201 www fibotec com Life Test and Burn In System for Butterfly Diodes User s Manual Rev01 LASER SAFETY This product may contain laser diodes of different laser classes not specified To ensure continued safety do not remove any covers or attempt to gain access to the inside of the product LTBIS RevO1 Safety precautions This manual contains a description of controls adjustments and procedures for normal operation of the system and its plug ins The unit should only be operated by qualified personnel who reviewed this manual before installing and applying the system Caution Electrostatic sensitive devices inside Observe precautions for handling 1 Overview The Life Test and Burn in System for Butterfly Diodes LTBIS is a 19 case system with plug ins to incorporate butterfly packaged laser diodes for burn in procedures and testing It allows for preselecting the laser current amp temperature and to operate the lasers in either constant current or constant power mode It allows for monitoring parameters like laser current amp temperature internal TEC current amp voltage The unit is commanded via an RS 232 serial interface separate plug in Up to 10 plug ins with one butterfly laser each can be installed per case 2 Installation 2 1 General At the rear panel of the
4. 19 case the mains input is combined with a fuse housing and the mains switch The case includes a power supply to provide up to 2A laser current and 3A TEC current for up to ten laser plug in unit with one laser each The system is provided with an interlock safety feature A sub D connector at the rear panel needs pins 1 and 2 to be shortened to operate the plug in units One LTBIS master plug in module per case is necessary to operate the system and to remotely control it Caution Switch the system off mains switch on rear panel before inserting or removing plug in modules 2 2 Insertion of butterfly lasers into plug in modules The modules can only be used with pump lasers of a predefined pin assignment see below Caution Inserting and operating lasers with pin designs different from the one described can damage the lasers The system gives no indications if a wrong type of laser is inserted LTBIS RevOl 2 Connections Pin Description Description Not connected Not connected Laser anode Laser cathode A Not connected Case ground 14 Peltier cooler Peltier cooler Thermistor Monitor anode Monitor cathode Fig 3 Single plug in module front view LTBIS RevO1 BF TIH 033 FC Aint 8 Buttertly Laser 1d Fig 5 single plug in module removed from system case top view with fiber adapter To remove replace a laser execute
5. 441mV Bit 1 874V volT TEC voltage 2 441 mV Bit DOOh 768d 768Bit x 2 441mV Bit 1 874V VOIN NTC voltage 2 441 mV Bit 300h 768d 768Bit x 2 441mV Bit 1 874V tp Butterfly case 0 2441 C Bit O68h 104d temperature 104Bit x 0 2441 C Bit 20 8 C monL Photodiode 2 441 uA Bit 334h 820d current 820Bit x 2 441 uA Bit 2 00MA 3 8 Command examples Enable laser Ch Set ACC mode set chl regC Maximum TEC current 2A gt 819 bit Maximum laser current 2 2A 901 bit Target laser current 1A 409 bit Target laser temperature 25 C Enable laser emission Change temperature laser Ch Target laser temperature 20 C Unte 1 38V 1380 bit Disable laser Ch Disable laser emission set chl tec333 set chX max385 set chl pow199 default set chl on set ch1 ntc564 set ch1 off LTBIS RevOl
6. YYY 3 5 1 ACC mode automatic current control In this mode the laser current is preselected with the command set chX powYYY and a Bit value YYY in hexadecimal numbers Via a proportionality factor given in the table below the requested laser current can be converted to the Bit value to be sent by the command An internal feedback loop keeps the current constant 3 5 2 APC modes automatic power control In these modes a feedback loop controls the laser current to keep the measured photodiode current at a level of preselected photodiode current set by the command set chX powYYY and a Bit value YYY in hexadecimal numbers Via a proportionality factor given in the table below the requested photodiode current can be converted to the Bit value to be sent by the command The relationship between the selected photodiode current the corresponding laser emission power and the resulting laser current has to be taken from the data sheet of the inserted laser by the user Caution The user is responsible for always checking for the maximum allowed currents laser diode and TEC of the lasers installed into the modules Commanding the adjustment of wrong parameters will destroy the inserted laser LTBIS RevOl 7 5 Monitor extern a eel Fig 6 schematic of the laser current control feedback circuit 3 6 Setting a module s laser diode temperature The temperature of the inserted laser s diode is m
7. anaged by a TEC thermo electric coupler inside the laser package It is measured by an NIC resistor inside the laser package The module includes a feedback loop to control the TEC current for keeping the laser diode at a fixed temperature This temperature can be preselected as follows e Refer to the laser data sheet for the proportionality NTC resistance vs diode temperature e Refer to the formula below for the proportionality NTC resistance vs NTC readout voltage e Refer to the table below for the proportionality factor of Bit value to voltage e Use set chX voINYYY to preselect the NTC voltage value calculated above The following formula gives the proportionality between the NTC resistance Rntc and the NTC voltage Untc needed to program the laser diode temperature Unte 2 5V x Rntc 1OkKOhm Rntc Typical values are 12 5kOhm 20 C Unte 1 38V 10 0kOhm 25 C Unte 1 25V 8 06kOhm 30 C Unte 1 11V To get information about the actual values of voltage and current applied to the inserted laser s TEC by the module use the commands get chX volT and get chX curl For reading the NTC voltage use get chX voIN LTBIS RevO1 8 Table of units for calculating data to preselect Command Parameter A D Sensitiv Example ity pow Laser diode 0 5 mA Bit 1300h 768d current 768Bit x 0 5 MA Bit 0 384A max Maximum laser 0 5 mA Bit 300h 768d diode current 768Bit x 0 5 MA Bit
8. closed After power up and after the interlock circuit being opened and closed again during operation all laser currents and TEC currents of all modules are reset to zero values The default value for the laser s NTC resistor voltage feedback to control the laser diode temperature is Untc 1 25V corresponding to 25 C 3 2 Plug in modules On the front panel of each module a green LED Power indicates that it is connected to the case A red Emission LED indicates laser emission from the optical connector All operational parameters of the lasers can only be controlled remotely After power up alll laser and TEC currents are set to zero and laser emission is disabled Each module owns a channel number from 0 to 9 to send commands to the corresponding laser 3 3 Computer control RS232 interface The system is controlled by sending line oriented commands based on the ASCII character set A colon 3A at the beginning of a new line indicates that the system is ready to receive a command prompt Commands are case sensitive and are processed after sending carriage return 0D and line feed 0A In response to a Command either requested data are sent or the command is echoed both followed by a new prompt In case of misspelling a command or in case of sending an unknown command an error message ERROR is the response Numbers are always hexadecimal and can be either upper or lowercase Do not omit leading zeroes i e t
9. d NTC voltage of laser X tp get the measured butterfly case temperature of laser X Caution Always disable laser emission set chX off before changing the laser current or the APC ACC modes LTBIS RevO1 6 3 5 Setting a module s laser current A laser can be operated in ACC mode automatic current control or in APC mode automatic power control In APC mode two different ways of controlling laser emission power can be selected One is by using the internal photodiode of the laser another by using an external photodiode connected to the laser s output fiber via an external coupler In all cases a maximum laser current must be chosen which is never exceeded in any operation mode or condition The sequence to control the laser current is as follows e Use set chX maxYYY to select the laser s absolute maximum current e Use set chX regC E I to select ACC or APC modes e Refer to the table below for the proportionality factor of Bit value to current e Use set chX powYYY to preselect the laser or photodiode current value To get information about the actual values of voltage and current applied to the inserted laser by the module use the commands get chX volL and get chX curL see chapter 3 4 4 set chX regZ change the laser operating mode Z Z C ACC mode preselect laser current with set chX powYYY Z l APC mode with internal laser diode preselect photodiode current with set chX pow
10. ype 000A instead of A A list of all commands and its documentation are given in the next chapter LTBIS RevOl 5 3 4 Serial Commands 3 4 1 General commands help show this help fwinfo display version number sernb display serial number 3 4 2 Commands to set target parameters Commands for preselection or readout of parameter values are a combination of set get channel number X 0 9 and a hexadecimal value YYY set chX lt param gt YYY set parameter for channel X 1 4 get chX lt param gt get parameter from channel X 1 4 lt param gt pow set get power YYY 000 FFF of laser X max set get maximum laser current YYY OOO FFF ntc set get ntc reference voltage YYY 000 FFF tec set get maximum tec current YYY 000 FFF 3 4 3 Commands for laser control set chX on enable emission laser X set chX off disable emission laser X set chX regZ change the laser operating mode Z of laser X to E C get chX reg get the laser operating mode Z C I of laser X get chX status get the emission status on off of laser X 3 4 4 Commands to retrieve actual data get chX lt param gt get parameter from channel X 1 4 lt param gt curl get the measured current of laser X volL get the measured voltage of laser X monl get the measured current of internal laser monitor diode of laser X curl get the measured TEC current of laser X volT get the measured TEC voltage of laser X volN get the measure
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