Users Manual
Contents
1. een 27 INOMETRI Xue Virtual Reference Analyser User s Manual Introducing the Dispersive Virtual Reference Analyser Congratulations on your purchase of the Inometrix Dispersive Virtual Reference Analyser This manual outlines the installation procedure as well as the use of the instrumentation software After reading this manual you should find that integrating the system with your tunable laser and using then software is a relatively simple and straightforward process As always if you do encounter any difficulties we are always here to help so please don t hesitate to contact us Inometrix Inc 35 Hemlock Way Grimsby Ontario Canada L3M 0A8 Phone 647 226 3715 Email sales inometrix com Web Site www inometrix com We hope you enjoy your new Dispersive Virtual Reference Analyser INNOMET RI X inc Virtual Reference Analyser User s Manual Installation Guide Step 1 Connect Power Cables and Peripherals ee ga T Wt Keyboard Mouse Video Card Connect monitor YO PP Power Supply Connect the keyboard mouse and screen provided with the system to the connections on the reverse side of the Dispersive Virtual Reference Analyser INNOMET RI X inc Virtual Reference Analyser User s Manual Step 2 Connect Trigger amp GPIB Cables Connections on Dispersive Virtual Reference Analyser A GPIB Port B Trigger in SMB side Connections on tun2. OBand 0 12 1 I I 1 I 1 I 1 I I 1 I 1 I E 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 1650 Wavelength nm Measurement Parameters Automatic Fine Balancing E of points 50 Coarse Balance Fine Balance Configuration Fabry Perot Coarse Balance Points in FFT 47 SA 2374 mam x Fit Spline Parameter nn Fine Balance Sensitivity Compression Parameter K 1 DvLv 3 33564E 6 ps nm interpolate spline 1 x C Manually input Lv Lv 0 37426791 m x Dispersive Virtual Reference Analyser vi Scan Filter Normalize Balance Fit Range Sweep Results INOMETRI INC Virtual Reference pattern 0 12 Dispersive Virtual Reference Analyser i Scan Parameters MaRS 0 06 Start wavelength 1510 nm 5 004 amp Stop wavelength 1640 nm 2 0 02 3 Output Power 3 dBm G 0 002 TLS Port GPIBO 20 INSTR gt 0 04 TLS mainframe Keysight 8164A Keysight 81648 0 06 0 08 Channel C LBand o Band 0 1 I I 1 i I I 1 i 1 I U 1 1 U I 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 1650 Wavelength nm Measurement Parameters Automatic Fine Balancing a of points 50 KA Coarse Balance Fine Balance Configuration Fabry Perot Coarse Balance Points in FFT gk SAR 27 zae Fine Balance Sensitivity eee L lt Fit Spline Parameter MAMA MARAS si Compression Parameter K 1 DvLv 3 33564E 6 ps nm E
3. INOMETRI X inc Dispersive Virtual Reference Analyser User s Manual December 2014 Inometrix Inc 35 Hemlock Way Grimsby Ontario Canada L3M 0A8 Phone 647 226 3715 Email sales inometrix com Web www inometrix com INOMETRI Xue Virtual Reference Analyser User s Manual Contents Introducing the Dispersive Virtual Reference Analyser nee 3 asci ACC TA TOIL A RR cus ee covet RP e e PR 4 Step 1 Connect Power Cables and Peripherals ssascissscisavssanewanansieonaveiaensennndossaseesavagasacoseennanansonniaoaseennerees 4 Step 2 Connect Trigger amp GPIB Cables usessessssersserrnssrensrrresrrrsrerssrrnsrtrsrtrnsrrnsrtesetrsrresrtesererereesrreseereses 5 Step 3 Connect your tunable laser SOULCE ceeccccescsceececeuececenecseenscceueceeeuececeueceeeeeeeeeeeeeueceeeueeeeeneeees 6 Step 4 Connect the deviceundertesttotheDUTPort Gene 7 Reflection based measurement CONFIGULATIONS cccccceseccccesscceceesececeuececeeeceeseueceseusecessugeceesenseeetes 7 Transmission based measurementconfigurations eee 9 Step 5 Turn on the instrumentandstartthesoftware eee 10 Step 6 Locate the detection gain switch les onthesideoftheinstrument 11 Step 7 Get to know your SOR Eman sia ce air aamir bn ale ln aa 11 Step 8 Scan the Sample DUT provided
4. Interpolate spline 1 x E Manually input Lv Lv 0 37455906 m By increasing the slider labelled Fine Balance Sensitivity and using the arrows adjust the length of the Dispersive Virtual Reference so that the interference pattern may be Virtually Balanced at a point within the bandwidth of the scan range The balance point is the location of the large peak valley in the amplitude modulation 17 INOMETRI INC Virtual Reference Analyser User s Manual Next we vary the dispersion of the dispersive virtual reference using the Compression Parameter K The compression parameter K is related to the second order dispersion length D L of the dispersive virtual reference by the relation D L K c where c is the speed of light in vacuum in meters per second The value of K may be either positive or negative If the device under test has a positive dispersion then a negative value of K produces the greatest compression for a given magnitude of K and vice versa Choose the sign of K that provides the greatest compression for a given magnitude Enter a value into the box for K and D L will be automatically calculated Compression Parameter k Del 3 33564E 6 ps nm Varying the value of K yields varying degrees of compression A sample compressed interference pattern produced by using a large value of K is illustrated below Dispersive Virtual Reference Analyser vi INOMETRIXunc Dispersive Virtual
5. Since T 4 T 3 lt Tmax the peaks valleys to the left of 1520 nm are not included in the calculation of second order dispersion Also since Ta 1 Ta 2 lt Tmax the peaks valleys to the right of 1615 nm are not included in the calculation of second order dispersion Therefore in this example only the peaks valleys between 1520 nm and 1615 nm are included in the dispersion calculation 9 peak valley points The flexibility to vary the Maximum deviation in fringe period centre of the scan range and Maximum deviation in fringe period edges of the scan range allows for variation in the maximum deviation depending on where the large peak is during the sweep For example if the peak is near the centre of the scan range then the period between visible points is large as shown above However when the 22 INOMETRI XX inc Virtual Reference Analyser User s Manual large centre peak is located near the edges of the scan range the period between visible points is smaller as shown below Reduced period between points at an anlak of scan range 0 2 01 P a m 5 T 01 0 2 1500 1510 1520 1530 1540 1550 1560 1570 1580 15 600 1610 1620 1630 1 Wavelength nm One may therefore reduce the tolerance for the Maximum deviation near the edges of the scan range in comparison to that near the centre The program then varies the tolerance linearly during the sweep In the previous example the error in the peak locations
6. 1620 1630 1640 1650 Wavelength nm Fit to Virtual Reference Pattern Swept 0 5 0 4 0 3 0 2 0 1 0 0 1 0 2 0 3 Amplitude au 0 4 I 1 I I I I I I j I I I I 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 1650 Wavelength nm Ly 0 374520432651502 m Current max deviation in fringe period 45 nm This tab is fully automated and shows the sweep from Lv minimum to Lv maximum set in the previous tab 24 INOMETRI INC The Results tab Virtual Reference Analyser User s Manual This tab has three sub tabs to display the results of measurements of first and second order dispersion This includes Group Delay Group Velocity Dispersion and Dispersion x Length Sample plots are illustrated in the following images x Dispersive Virtual Reference Analyser vi Scan Filter Normalize Balance Fit Range Sweep Results INOMET RI Inc l Group Delay Dispersive Virtual Reference Analyser x 1249 5 x Scan Parameters xx 1249 48 x x Start wavelength 1510 nm 1249 46 k x nm x Stop wavelength 1640 124944 gt x Output Power dB d 2 1249 42 x TLS Port L Li xx 6 GPIBO 20 INSTR di xX TLS mainframe Keysight 8164A a PEN x Keysight 8164B XX 1249 36 xX Channel C L Band a O Band 1249 34 x xX 1249 32 xx Measurement Parameters xX 12493 a x 50 dt 1249 28 xX x Configu
7. Balance Fit Range Sweep Results INOMETREX inc TIED 016 Dispersive Virtual Reference Analyser 015 014 Scan Parameters 013 Start wavelength 1510 nm 012 Stop wavelength 1640 desin 011 0 Output Power 3 dBm A 0 09 TLS Port p 20 GPIBO 20 INSTR v 5 008 TLS mainframe Keysight 8164A X 007 Keysight 81648 0 06 Channel C LBand 005 OBand idi 0 03 Measurement Parameters 0 02 of points 50 0 01 gt 0 Configuration Fabry Perot 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 Wavelength nm Lo m Apply FFT Filtering You should immediately hear a click from the tunable laser and start to see the laser sweep between the Start wavelength and the Stop wavelength at the set Output Power Please consult the user s manual of the particular tunable laser source used to determine the minimum and maximum wavelength output power In order to allow for the use of multiple tunable lasers we do not restrict these values 27 INOMETRIX nc Virtual Reference Analyser User s Manual Bandwidth Range Adjustments The circulator provided with the standard system configuration has a bandwidth in the C and L band If you would like to characterize components outside this region please contact us for a circulator in your region of interest and for instructions on how to install a new circulator Power Level Adjustments The optical power from the tuna
8. Reference Analyser Scan Parameters Start wavelength 1510 nm Stop wavelength 1640 Output Power 3 dBm TLS Port GPIBO 20 INSTR v TLS mainframe Keysight 8164A Keysight8164B Channel C LBand OBand Measurement Parameters of points 50 Configuration Fabry Perot Scan Quit Scan Filter Normalize Balance Fit Range Sweep Results Virtual Reference pattern 0 12 01 0 08 0 06 0 04 0 02 0 0 02 0 04 0 06 0 08 0 1 0 12 Ti I I I I I I I I I I I I I 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 Wavelength nm Amplitude au Automatic Fine Balancing Coarse Balance Fine Balance Coarse Balance Points in FFT a 2374 p vE Fine Balance Sensitivity Fit Spline Parameter Compression Parameter K Galli DvLv 0 0166782 ps nm Interpolate spline Manually input Lv 1640 1650 1 x Lv 0 37455906 m Once this is complete click on the Fit tab 18 INOMET RI Ainc Virtual Reference Analyser User s Manual x Dispersive Virtual Reference Analyser vi Scan Filter Normalize Balance Fit Range Sweep Results INOMET REX inc 5 Fit pattern nee 04 Dispersive Virtual Reference Analyser Scan Parameters Start wavelength 1510 nm a 32 m 01 Stop wavelength 1640 oll v 3 Output Power 3 dBm B 0 T TLS Port GPIB
9. nm Include effect of third order dispersion v Max deviation in fringe period edges of scan range 15 nm Minimum of peak valley points in calculation 5 In this tab the sweep range of the dispersion measurement can be set manually or automatically To set the sweep range automatically place a check mark in the Automate Range Measurement check box Automate Range Measurement To set the sweep range manually leave the Automate Range Measurement check box unchecked Automate Range Measurement E You may now use the sliders labelled Sensitivity to control the amount the Dispersive Virtual Reference path length Lv changes when the B arrows are pressed We may now set the spectral range of the dispersion measurement by choosing the maximum and minimum value of the simulated Dispersive Virtual Reference path Lv In the top plot labelled Minimum Lv press the pa button to decrease the length of the Dispersive Virtual Reference path Lv and move the large peak to one side of the bandwidth direction of movement in the spectral domain depends on the sign of the dispersion of the device under test To measure second order dispersion two peaks or two valleys are required on both sides of the largest Min OK i peak valley point of symmetry in the interference pattern and the indicator is bright blue when this is true 20 INOMET RI Anc Virtual Reference Analyser User s Manual In the top plot label
10. plots show the original scan and the result of FFT filtering The bottom plot isan FFT of the original raw scan which can be filtered using the slider tabs Only half of this plot is unique i e O to 0 5 contains the same information as 1 to 0 5 so one side may be filtered out without any loss of information This step is typically employed to remove any low frequency components of the interference pattern 14 INOME TR Anc Virtual Reference Analyser User s Manual When this step is complete click on the OK button to advance to the next tab If the Normalize scan check box was checked on the Scan tab the software will automatically advance to the Normalize tab Otherwise it will advance to the Balance Fit tab The Normalize tab _ Dispersive Virtual Reference Analyser vi Scan Filter Normalize Balance Fit Range Sweep Results INOMET R ins Normalization amplitudes interference N Peaks Fa Valleys A 01 er 0 08 Dispersive Virtual Reference Analyser iat Scan Parameters Amplitude a u a Start wavelength 1510 nm 0 02 Stop wavelength 1640 nm ses Output Power 3 dBm 0 08 TLS p I 01 Ti 1 1 I I 1 1 1 1 I 1 i i 1 1 I ort GPIBO 20 INSTR 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 1650 TLS mainframe Keysight 8164A Wavelength nm i Se a ee Window size ya m0 Channel C LBand Normalized scan OBand 1 25 1 Measurement Paramet
11. spline and in the text box labelled factor enter the number of times to interpolate between spline points This functionality is not typically required for most measurements though and the default is not to use it When this step is complete click on the OK button to advance to the next tab 19 INOMETRIAnc Virtual Reference Analyser User s Manual The Range tab x Dispersive Virtual Reference Analyser vi Scan Filter Normalize Balance Fit Range Sweep Results INIORAE TR ins Automate Range Measurement Accept patterns with noise on centre peak Minimum Lv Dispersive Virtual Reference Analyser 0 4 03 Scan Parameters pr 2 01 U ne 0 Start wavelength 1510 nm 8 a 01 Stop wavelength 1640 Jal 0 2 Output Power 3 dBm jo 7 e i I I I I 1 I I I I I I I U I TLS Port L GPIB0 20 INSTR 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 1650 cea Wavelength nm TLS mainframe 6 Keysight 8164A ii Min OK 2 Keysight 8164B lt lt gt gt Lvminimum 10 374463818950381 m Maximum Lv C LBand ine O Band K r 0 2 Measurement Parameters 7 w fo j of points 50 E gt lt 0 2 Configuration Fabry Perot 0 Ti I j 1 1 j 1 1 1 I I I I geni 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 1650 Wavelength nm sae as MaxOK Quit OK Max deviation in fringe period centre of scan range 15
12. turn the connectors too tightly as this will damage the FC APC connector heads inside the system INOMETRI Xone Virtual Reference Analyser User s Manual Step 4 Connect the device under test to the DUT Port Reflection based measurement configurations Fabry Perot standard configuration The Fabry Perot configuration is the most commonly used setup since it enables convenient single ended measurements In this setup there are two ways to connect a device under test to the instrument illustrated below Configuration A Configuration B Configuration A The device under test is connected directly to the DUT port Configuration B A sacrificial patchcord is connected between the DUT port and the device under test We highly reccommend using Configuration B exclusively for all reflection based measurements since it protects the FC APC connector inside the DUT port and reduces the possiblility that dirt dust is introduced into the DUT port It is also easier to clean the FC APC connector of the patch cord Caution Be very careful not to overturn the connectors at the FC APC to FC PC interface as the connectors may break INOMETRI Xue Virtual Reference Analyser User s Manual The measurement setup in reflection will depend on the configuration of the device under test In order to characterize a device under test there must be two reflection points surrounding it This is typically achieved using the reflections f
13. 0 20 INSTR v 01 TLS mainframe Keysight 8164A Keysight 8164B ee Channel C LBand i O Band i 0 4 1 1 1 1 I j L I 1 1 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 1650 Measurement Parameters Wavelength nm of points 50 Coarse Balance Fine Balance Fit Configuration Fabry Perot m Coarse Balance Points in FFT 4 D 2374 sae Fine Balance Sensitivity GAR sue lt lt gt gt lord Fit Spline Parameter O 616 Quit Compression Parameter K 5000 DvLv 0 0166782 ps nm OK Interpolate spline 1 x Manually input Lv Lv 0 37455906 m Vary the slider labelled Fit Spline Parameter to filter out the high frequency component in the interference pattern The value should be high enough that the peaks and valleys have a good contrast but low enough that there is only one point located for every peak marked by X s There is a wide range of acceptable values for the Fit Spline Parameter since we are only concerned with measuring the phase of the interference and this does not depend on the amplitude of the interference pattern The length of the Dispersive Virtual Reference path Lv may also be varied directly by placing a check mark in the check box labelled Manually input Lv which allows the value of Lv to be input directly to the text box beside Lv If a higher resolution is needed on the spline fit plot on the Fit tab place a check mark in the box labelled Interpolate
14. 02 of points 50 0 01 Configuration Fabry Perot 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 Wavelength nm Normalize scan Apply FFT Filtering The front panel is divided into two sections left and right as shown in the image above The left section contains controls for the Scan Parameters and Measurement Parameters which are set before experiment runtime The right section contains the controls that are used during experiment runtime 11 INOMETR X inc Scan Parameters Start wavelength 1510 nm Stop wavelength 1640 ai Output Power 3 dBm TLS Port 4 GPIBO 20 INSTR TLS mainframe Keysight 8164A Keysight 61646 Channel C Band O Band 12 Virtual Reference Analyser User s Manual The Scan Parameters section sets the parameters for controlling the tunable laser source The controls include the Start wavelength Stop wavelength and Output power As there are various tunable laser sources that may be used with the system the program does not prevent out of bounds parameters from being input The user must ensure that the maximum minimum wavelengths and output power are within the bounds of the particular tunable laser used The TLS port is the GPIB address of the tunable laser mainframe used with the unit By clicking on the dropdown menu the software automatically searches for attached GPIB communication ports There is also a Refresh option in t
15. Output Power 3 dBm 0 0048 I TLS Port GPIBO 20 INSTR v 0 0046 E TLS mainframe Keysight 8164A Keysight 81648 amp 9 0044 Channel C LBand 0 0042 Xx OBand x x x 0 004 XxX XXX X X XX Measurement Parameters x xX 0 0038 x of points 50 0 0036 Configuration Fabry Perot 0 0034 1 1545 1550 1555 1560 1565 1570 Wavelength nm Scan p Load Group Delay Group Velocity Dispersion Dispersion x Length 1 1 j 1 I i 1580 1585 1590 1595 1600 1605 RX di Export Results The dispersion measurement results may be exported to a generic tab delimited text file that may be opened in Matlab Labview Excel Notepad or any text processing software To export the results click on and save the file to the hard drive or a USB Savein EE Desktop L or Libraries thee System Folder Recent Places ia 7 N Computer gt System Folder Desktop Libraries Computer 26 INOMETR X nc Virtual Reference Analyser User s Manual Step 8 Scan the sample DUT provided In this step we use the system to measure a known sample to ensure everything is working as expected The sample provided with the Dispersive Virtual Reference Analyser is a short length FC PC to FC PC connectorized SMF28 patch cord Press the Scan button on the left side of the front panel x Dispersive Virtual Reference Analyser vi Scan Filter Normalize
16. able laser mainframe Agilent Keysight 816XX A B series C GPIB port J m Gea de Mo EE D Trigger out BNC side of cable cee E Remoteinterlock resistor 1 Connect a GPIB cable provided to the GPIB port of the Dispersive Virtual Reference Analyser A Connect the other side of the GPIB cable to the GPIB port on the tunable laser mainframe C 3 Connect the SMB side of the SMB to BNC cable provided to the SMB port labelled Trigger in B on the Dispersive Virtual Reference Analyser 4 Connect the BNC side of the SMB to BNC cable provided to the port labelled Trigger out E on the tunable laser mainframe 5 Ensure that the remote interlock resistor D is connected INOMETRI Xue Virtual Reference Analyser User s Manual Step 3 Connect your tunable laser source Note tunable laser sold separately Position and number of ports vary by model A Laser in port of the Dispersive Virtual Reference Analyser B Laser out port of the tunable laser Connect an FC APC to FC APC optical patch cord green connectors on both sides between the Laser in port A of the Dispersive Virtual Reference Analyser and the Laser out port B of the tunable laser If you are using an 81600B series tunable laser with two output ports use the High power output Notes 1 Caution Use only FC APC to FC APC patch cords between ports A and B 2 Caution Be careful not to
17. ble laser may be adjusted programmatically from the Scan Parameters The gain of the detector built into the Dispersive Virtual Reference Analyser may also be adjusted using the controls at the side of the system If the intensity measurements are clipped produce values greater than 1 in the raw scan pattern and power cannot be further reduced reduce the detector gain Conversely if the power output of the tunable laser is maximized and the detected signal is low increase the detector gain 28 INOMETRI Xone Virtual Reference Analyser User s Manual Cleaning the connectors The connectors at the Laser IN and DUT ports may occasionally require cleaning Use a screwdriver to remove the screws not coloured green highlighted in red in the image below Carefully pull out the connector and a short length of the fiber cable attached Remove the connector to clean the fiber When cleaning is complete reconnect the fiber and connector and reinstall the connectors to the front panel When the system is not in use please use the white caps provided with the system to prevent dust from entering the optical ports of the front panel 29
18. e Scan button starts the tunable laser scan and begins the measurement Pressing the Load button imports the raw scan data interference pattern from a saved scan Pressing Quit exits the software The blue progress bar indicates the progress through the measurement Scan Filter Normalize Balance Fit Range Sweep Results Raw scan au litude 3 lt 0 21 0 2 0 19 0 18 0 17 0 16 0 15 0 14 0 13 0 12 0 11 01 0 09 0 08 0 07 0 06 0 05 0 04 0 03 0 02 0 01 0 i f r i i i i i i i i 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 1650 Wavelength nm Apply FFT Filtering 13 INOMET RI Anc Virtual Reference Analyser User s Manual After a scan has been completed the Save Raw Scan button on the Scan tab saves a generic data file tab delimited text of the raw interference pattern intensity vs wavelength This file may be loaded for analysis and dispersion characterization at a later time using the Load button If desired the raw interference pattern can be normalized and filtered by placing a check mark in the Normalize scan and Apply FFT Filtering check boxes By default however these boxes are left unchecked as this step is usually not necessary The slider bar along the wavelength axis can be used to reduce the bandwidth of the scan range if desired To reduce the bandwidth simply click a
19. eak place a check mark in the check box A cept patterns with noise on centre peak bi The control Include Effect of third order dispersion Jetermines if the algorithm that includes the effect of third order dispersion in the calculation of second order dispersion is to be used By default this box is checked to include third order dispersion When measuring a device with low third order dispersion however this box may be unchecked to ignore the effect of third order dispersion The reason for using an algorithm that ignores third order dispersion is that it can help to reduce the scatter in the dispersion plot no noise from measuring third order dispersion 23 INOME TR When this step is complete click on the OK button to advance to the next tab The Sweep tab INOMETR X inc Dispersive Virtual Reference Analyser Scan Parameters Start wavelength 1510 nm Stop wavelength 1640 ili Output Power 3 dBm TLS Port GPIBO 20 INSTR v TLS mainframe Keysight 81644 Keysight 81648 Channel C fL Band OBand Measurement Parameters of points 48 Configuration Fabry Perot INC Virtual Reference Analyser User s Manual Scan Filter Normalize Balance Fit Range Sweep Results Virtual Reference Pattern Swept 0 125 0 1 0 075 0 05 0 025 1 0 025 0 05 0 075 Amplitude au 0 1 1 1 1 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610
20. easurement may be performed using a Mach Zehnder configuration In this configuration two couplers with balanced equal arm lengths are used and the device under test is placed in one of the paths This configuration is useful when the device under test can only be characterized in transmission Laser out Tunable laser Balanced couplers DUT port Dispersive Virtual Reference Analyser _Z B Device under test INOMETRI Xue Virtual Reference Analyser User s Manual Step 5 Turn on the instrument and start the software Push the Power button on the instrument NOMETRIAnc Click on the Dispersive Virtual Reference Analyser shortcut 10 INOMETRI X inc Virtual Reference Analyser User s Manual Step 6 Locate the detection gain switch es on the side of the instrument Teri e J 8 oe Ve Ay isenta e ino Bs Mei a Pa Step 7 Getto know your software Below is an image of the front panel of the Dispersive Virtual Reference Analyser Scan Fitter Normalize Balance Fit Range Sweep Results INOMETREX inc os 016 Dispersive Virtual Reference Analyser 015 014 Scan Parameters 013 Start wavelength 1510 nm 012 Stop wavelength 1640 nm 011 01 Output Power 3 dBm 0 09 TLS Port i 20 lt GPIBO 20 INSTR _v 5 008 TLS mainframe o Keysight 8164A 3 0 07 Keysight81648 2 0 06 Channel C LBand 0 05 O Band 004 Measurement Parameters paS 0
21. ers 0 5 of points 50 2 025 w figuration Fabry Perot oa Configura g abry Pero 2 025 amp 05 Scan 0 75 1 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 1650 Guit Wavelength nm In the Normalize tab use the Window size slider bar to vary the number of data points used in the moving window that is used to scale the amplitude of the raw interference scan This processing scales the interference pattern so that the amplitude is normalized between 1 and 1 arbitrary units and removes any noise in the amplitude of the interference pattern When this step is complete click on the OK button to advance to the next tab 15 INOMET RI Anc Virtual Reference Analyser User s Manual The Balance Fit tab x Dispersive Virtual Reference Analyser vi Scan Filter Normalize Balance Fit Range Sweep Results INOMET REX inc f Power Spectrum 3 5E 5 Dispersive Virtual Reference Analyser 3E 5 Scan Parameters 9 SE 5 Start wavelength 1510 nm 2 e s 3 nm Tr Stop wavelength 1640 3 15E 5 Output Power 3 dBm a 1E5 TLS Port GPIB0 20 INSTR v i TLS mainframe Keysight 8164A Keysight 8164B 0 Channel C LBand 5E 6 I 1 I 1 I 1 l 1 I 1 A R 0 5E 11 1E 12 1 5E 12 2E 12 25E 12 3E 12 35E 12 4E 12 4 5E 12 5E 12 5 5E 1 Spatial Frequency 1 m Measurement Parameters Peak to reference 1 Peak Frequency 2 63692E 11 l m of poi
22. he dropdown menu to search for new connections Select the GPIB address of the tunable laser The TLS mainframe is the mainframe of the tunable laser source used with the unit The unit is compatible with legacy 816XA and new 816XB tunable laser source mainframes from Keysight formerly Agilent Technologies The Channel selector is visible on systems with more than one DUT port depending on the model This image shows a model that is capable of characterizing devices in the C L band as well as the O band INOMETRIAnc Measurement Parameters of points Configuration Fabry Perot Load uit The Scan tab Xx Dispersive Virtual Reference Analyser vi INOMETRIXinc Dispersive Virtual Reference Analyser Scan Parameters Start wavelength 1510 nm Stop wavelength 1640 soi Output Power 3 dBm TLS Port GPIB0 20 INSTR v TLS mainframe Keysight 8164A Keysight 81648 Channel C LBand OBand Measurement Parameters of points 50 Configuration Fabry Perot Scan 50 Virtual Reference Analyser User s Manual The Measurement Parameters section sets the pre runtime experiment parameters The of points is the desired number of measured points in the dispersion curve Note that this number may be reduced for scans with noise In the Configuration dropdown menu select the configuration used in Step 4 Configuration ee Michelson Mach Zehnder Bulk Element ie FBG Pressing th
23. led Maximum Lv press the L button to increase the length of the Dispersive Virtual Reference path Lv and move the large peak to one side of the bandwidth direction of movement in the spectral domain depends on the sign of the dispersion of the device under test To measure second order dispersion two peaks or two valleys are required on both sides of the largest peak valley point of symmetry in the interference pattern and the indicator oe is bright blue when this is true An alternative method for setting the Maximum Lv and Minimum Lv value is to input their values Ly minimum m Ly maximum mi directly to the text boxes and Below the two plots in the Range tab are a few additional controls Max deviation in fringe period centre of scan range 1 5 nm Include Effect of third order dispersion Ei Max deviation in fringe period edges of scan range 15 mm Minimum of peak valley points in calculation 5 For most measurements these values can be left at their defaults However for users who wish to optimize further reduce the scatter in the dispersion measurement results these values may be adjusted To use these controls however one must first understand how they affect the measurement of dispersion from the interference pattern Since second order dispersion is measured using the phase of the interference pattern the locations of ALL the peaks and valleys of the interference pattern are critical The interference pattern howeve
24. limited the number of useable points in the Minimum of peak valley points in calculation 5 sets the minimum number of peak or valley points required in order for a particular interference pattern to be acceptable for use in the calculation of second order dispersion The minimum number of peak valley dispersion calculation to 9 The control points required for a measurement of second order dispersion to be possible is 5 since the large peak and at least one peak and one valley on each side of the large peak are required If the number of useable points in a particular interference pattern is below the number specified in Minimum of peak valley points in calculation then that interference pattern is not used to calculate second order dispersion and the value of Lv is incremented to see if the measurement can be made at a slightly different wavelength As a result increasing this number results in higher accuracy however it also leads to a greater number of discarded points It is important to note that the Minimum of peak valley points in calculation must be less than the total number of peak valley points in the scan range Also note that there are less peak valley points when the large peak is at the centre of the scan range than when it is at the edges of the scan range where shorter period peaks valleys are visible To accept interference patterns in which the large central peak has noise multiple peaks valleys located on central p
25. nd drag the sliders The slider on the left sets the minimum wavelength and the slider on the right sets the maximum wavelength of the bandwidth subset When finished click on the OK button to proceed to the next tab If the Normalize scan and Apply FFT Filtering check boxes are checked then the program automatically advances to the Filter tab If they are unchecked the program skips to the Balance Fit tab The Filter tab optional Dispersive Virtual Reference Analyser vi Scan Filter Normalize Balance Fit Range Sweep Results INOMETRIXunc Original Filtered 0 225 01 Dispersive Virtual Reference Analyser 0 2 0 075 0 175 0 05 Scan Parameters 3 0 15 7 0025 0125 Start wavelength 1510 nm S g E A a a 0 025 Stop wavelength 1640 ss d 0 05 Output Power 3 dBm ia 0 075 TLS Port GPIBO 20 INSTR _ 0 i i i i i i O1 i i i i 1500 1520 1540 1560 1580 1600 1620 1640 1660 1500 1520 1540 1560 1580 1600 1620 1640 1660 TLS mainframe Keysight 8164A Wavelength nm Wavelength nm D Keysight8164B FFT 1500 SAE C LBand OBand 1000 Measurement Parameters s 00 ra g oo of points 50 2 500 Configuration Fabry Perot 1000 Scan 1500 j 1 1 1 i 1 j i 1 1 j 1 j 1 1 j 1 0 005 01 015 02 025 03 035 04 045 05 055 06 065 07 O75 08 085 09 09 1 a Pa The Filter tab may be used to filter out frequency components in the raw scan The top two
26. nts 50 Configuration Fabry Perot Coarse Balance Points in FFT a 1788 Scan Fine Balance Sensitivity O jam lt lt gt gt toad Fit Spline Parameter D Quit Compression Parameter K 1 DvLv 3 33564E 6 ps nm C Interpolate spline 1 x C Manually input Lv Lv 0 36397562 m In this tab there are three sub tabs Coarse Balance Fine Balance and Fit With the Coarse Balance tab selected gradually increase the slider labelled Coarse Balance Points in FFT until there is a peak visible in the power spectrum If there is more than one peak measurement of a DUT that is a cascade of elements i e more than two reflection points then change the number in the Peak to reference box to select the appropriate cavity For most measurements however there is usually only one peak and this number is left at its default value of 1 Once a peak is visible click on the Fine Balance sub tab 16 INOMET RI Anc Virtual Reference Analyser User s Manual x Dispersive Virtual Reference Analyser vi Scan Filter Normalize Balance Fit Range Sweep Results INOMETRI INC Virtual Reference pattern 01 Dispersive Virtual Reference Analyser i Scan Parameters ME 0 04 Start wavelength 1510 nm 5 0 02 2 Stop wavelength 1640 ak v o Fd Output Power 3 dBm g 0 02 lt 004 TLS Port GPIBO 20 INSTR TLS mainframe Keysight 8164A mii Keysight8164B 0 08 01 aaa C LBand
27. r may include noise that can affect this measurement These controls set the parameters for filtering out this noise from the measurement process Max deviation in fringe period centre of scan range 15 nm Max deviation in fringe period edges of scan range 15 nm The first set of controls sets the maximum allowable variation in the period of the interference pattern For example in the plot below the deviation in the fringe period is the difference between T n and T n 1 This deviation must be less than the Maximum deviation in fringe period Tmax i e T n T n 1 lt Tmax Note the flexibility to vary the maximum deviation for the centre of the scan range and the edges of the scan range will be discussed later 21 INOMETRI Anc Virtual Reference Analyser User s Manual T 2 TE T0 bias 0 2 0 15 0 05 e 0 05 0 15 0 2 0 25 l l l l l l l l l l l l l l 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 Wavelength rm When this condition is violated only the points up to the peak where the violation occurred are used in the dispersion calculation For example if the interference plot has noise in it such that peaks are erroneously located as illustrated below 4 T 2 Ti TE Ti a 0 2 0 15 5 0 05 E x I 0 05 0 2 0 25 l l l l l l l l l l l l l l l 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 Wavelength nm
28. ration Fabry Perot 1249 26 f i 1 f f f l 1 1 l 1540 1545 1550 1555 1560 1565 1570 o 1575 1580 1585 1590 1595 1600 1605 Wavelength nm zam AF w r Load l Quit Group Delay Group Velocity Dispersion Dispersion x Length E a _ Dispersive Virtual Reference Analyser vi Scan Filter Normalize Balance Fit Range Sweep Results INIORAETRI ING i Group Velocity Dispersion Dispersive Virtual Reference Analyser mini 0 0044 Scan Parameters 0 0046 0 0048 Start wavelength 1510 nm gi _ xXx XX XX Stop wavelength 1640 p gt 0 0052 xX xXXXX x Output Power 3 dBm 0 0054 x yT v 0 0056 TLS Port GPIB0 20 INSTR gt xxx 0 0058 x KX XX TLS mainframe Keysight 8164A 0 006 x xx Keysight 81648 x 0 0062 x xX j Channel C LBand 0 0064 XX x OBand 0 0066 0 0068 Measurement Parameters 0 007 of points 50 0 0072 0 0074 Configuration Fabry Perot 0 0076 1 I I 1 I 1 I I 1 I 1 1 1540 1545 1550 1555 1560 1565 1570 1575 1580 1585 1590 1595 1600 1605 Wavelength nm Re tot mm asics 25 INOMETRIAnc Virtual Reference Analyser User s Manual x Dispersive Virtual Reference Analyser vi Scan Filter Normalize Balance Fit Range Sweep Results INOMETREX nc i Dispersion x Length Dispersive Virtual Reference Analyser 0 0054 Scan Parameters 0 0052 Start wavelength 1510 nm Stop wavelength 1640 lt 0 005
29. rom flat FC PC connectors To ensure that there is only one reflection from each side of the device under test alternating FC APC and FC PC connectors are used Some examples of possible configurations are illustrated below Device under test is FC PC connctorized on both sides DUT Port FC APC to FC APC patch cord recommended Device under test gt Device under test has one FC APC connector and one FC PC connector DUT Port FC APC to FC PC patch cord Device under test Device under test is FC APC connctorized on both sides DUT Port FC APC to FC PC patch cord Device under test FC PC to FC APC patch cord If the device under test is a bulk element for example a fiber Bragg grating then the following configuration may be used DUT Port FC APC to FC APC patch cord recommended Device under test 4 Note An FC APC to FC PC connector may be used if the device under test is FC APC connectorized INOMETR X nc Virtual Reference Analyser User s Manual Michelson The interference pattern produced by the Fabry perot setup is mathematically equivalent to the setup below when the length of the coupler arms are balanced equal The following setup may be advantageous over the Fabry perot setup if it is desireable to use mirrors as illustrated bleow to increase the reflected power DUT Port Coupler _Z gt Device under test Transmission based measurement configurations Mach Zehnder A transmission based m
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