Quantum Instruments Cascade Laser Starter Kit guide

Starter Kit Instruction Manual

Appendix

58

•As a rule of thumb, the overall dissipated power (sum of DC Bias current dissipation and pulse current dissipation) must never be higher than the average dissipated power given by the high- est current / voltage / temperature combina- tion speciﬁed in the datasheet.

Take into account that the average dissipated power for a given pulse current I, pulse voltage U, and duty cycle d is given by d x I x U, whereas the dissipated power due to a Bias current IB is given by IB x U. (U is the voltage on the laser, but it is safe for this calculation of Bias current dissipation to use the voltage on the LDD pulser input.)

Current and voltage ranges of the Bias-T cir- cuit

Since the input stage of the Bias-T is a bipo- lar transistor, applied voltage must be higher than about 0.6V to start Bias current. The in- put stage has maximum voltage limit of 2.6V, but the laser itself may be destroyed at lower Bias-T control voltage already, therefore the maximum rating has to be checked with the abovementioned rules and together with Alpes Lasers SA.

The monitor output (if available) allows mea- surement of applied DC Bias current: Its volt- age divided by 10OΩ gives Bias current. In general, Bias current can be in the range of 0.1A, but this must be checked with Alpes Lasers SA before.

CAUTION !

Avoid reverse polarity on the input!

Image 59

Quantum Instruments Cascade Laser Starter Kit manual Current and voltage ranges of the Bias-T cir- cuit

Contents

Instructions Manual Web version Quantum Cascade Laser Starter Kit Contents Use InstallationTroubleshooting Maintenance Overview Appendix Manufacturer IdentiﬁcationDocument Limited waranty Compliance GeneralChapter overview Generalities Personnel GlossaryPersons Product Description style Commands styleProcedure style Typographic conventions Possible cause ProblemProcedure eﬀects style See page x-y Troubleshooting stylePage Introduction Safety InstructionsImportance of safety instructions Non-compliance with the safety regulations Compliance and informa- tion General safety instructionsEnvironmental conditions System Composition Description Geometry of QC lasers DFB and FP Quantum Cascade LasersIf no conﬁguration is speciﬁed, the DN pad is used Description Speciﬁcations Electrical model Electrical model characteristics LLH100 external view description Laboratory Laser HousingLLH100 LLH100 internal view Laboratory Laser Housing internal view Thermo-Electric Cooler TEC and PT100 connections Speciﬁcations of the Peltier connector Measurement connection Speciﬁcations of the measurement connector QCL pulser switching unit front and rear view QCL pulser switching unitLDD100 Timing data QCL pulse switching measuring unitGeneralities Measured voltages Duty cycle calculation Laser peak current Accuracy considerations Laser peak voltageAverage dissipation QCL pulser timing unit TPG128 Trigger and logic output signals Ω TTL driver circuit Peltier and PT100 connections QCL temperature controllerTCU151 Standard items InstallationChapter overview Packing list General 110-120V, 60Hz USA 220-240V, 50Hz Europe Setting the appropriate AC voltage on TCU151Procedure Before beginning Installing the starter Kit Connecting Starter Kit QCL pulse timing unit com- mand description Use TCU151 temperature controler front panel TCU151 command description Proceedings Laser utilisationOverview Starting the TPG128 Interlock utilisation Procedure Interlock utilisation Principle TroubleshootingPower supply reaches max cur- rent for a very low voltage DC power supply is not ﬂoating There is no contact with the laser Laser draws current but gives no lightLaser does not draw current QCL laser is not used with the LLH and is grounded Overview MaintenanceHow to remove the covers of TCU151 and TPG128 Quantum Cascade Laser replace Ment Replacement procedures + LLH100 connection Facet on the case, it is extremely fragile Exchanging the laser QCL UP and DN position Exchange Humidity If the ambient atmosphere is humid this is Needed material TCU151 temperature con Troller interlock settingProcedure interlock setting Before beggining interlock set Ting Generalities Calibaration proceduresProcedure calibration 1 TPG128 calibration TPG128 main board TPG128 main board Procedure +5V/-5V power supply check 2 TCU151 temperature controller calibration = 1.22 to Sensing level and range adjustement Temperature Reference oﬀset adjustment LCD screen should display 1.00 a Current/Voltage ratio adjustmentSetting Oscillator check Starting the power section of the instru Ment 7V = 70 C If needed, adjust it with the trimmer P92 → Value displayed should tend to the deﬁned value Current adjustment→ Value displayed ≤ 1A → The red LED 1 should turn oﬀ Miscellaneous functions testing Temperature Limit testing→ The temperature displayed 2 should be 035 C Threshold on Frequency modulation technique Tildas Application notesDetection techniques Direct absorption Photoacoustic technique Photoacoustic detection General AppendixBias Circut Bias-T Utilisation What has to be kept in mind before use? Avoid reverse polarity on the input Current and voltage ranges of the Bias-T cir- cuit Unpacking instructions for NS submounts Unpacking NS laser from its transportation box