Quantum Instruments Cascade Laser Starter Kit manual Electrical model characteristics

Page 16

Starter Kit Instruction Manual

Description

15

4.3.4Electrical model

The QCL can be modelised in a RC circuit.

Electrical model characteristics

The values given below apply for a 10µm laser wavelength.

−

+−

=

R1

C1

+

C2

Fig.5: Electrical model of QCL

Note: Voltage and resistor values may vary according to the type of laser.

R1 : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 to 20Ω when a voltage of 4 to 6 Volts is applied

R1 : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 to 4Ω up to 10 - 12 Volts

R1 : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 to 20Ω over 12 Volts, after which the laser no longer operates

C1 : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100pF, capacitor between the anode and the cathode

C2 : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <100pF, depending on your mounting of the laser

Image 16

Contents Quantum Cascade Laser Starter Kit Instructions Manual Web versionContents Installation TroubleshootingMaintenance Overview UseAppendix Identiﬁcation DocumentLimited waranty ManufacturerGeneral Chapter overviewGeneralities ComplianceGlossary PersonsProduct PersonnelCommands style Procedure styleTypographic conventions Description styleProblem Procedure eﬀects styleSee page x-y Troubleshooting style Possible causePage Safety Instructions Importance of safety instructionsNon-compliance with the safety regulations IntroductionEnvironmental conditions General safety instructionsCompliance and informa- tion Description System CompositionDFB and FP Quantum Cascade Lasers If no conﬁguration is speciﬁed, the DN pad is usedDescription Geometry of QC lasersSpeciﬁcations Electrical model characteristics Electrical modelLaboratory Laser HousingLLH100 LLH100 external view descriptionLaboratory Laser Housing internal view LLH100 internal viewSpeciﬁcations of the Peltier connector Thermo-Electric Cooler TEC and PT100 connectionsSpeciﬁcations of the measurement connector Measurement connectionQCL pulser switching unitLDD100 QCL pulser switching unit front and rear viewQCL pulse switching measuring unit GeneralitiesMeasured voltages Timing dataLaser peak current Duty cycle calculationAverage dissipation Laser peak voltageAccuracy considerations Trigger and logic output signals Ω TTL driver circuit QCL pulser timing unit TPG128QCL temperature controllerTCU151 Peltier and PT100 connectionsInstallation Chapter overview Packing listGeneral Standard itemsProcedure Setting the appropriate AC voltage on TCU151110-120V, 60Hz USA 220-240V, 50Hz Europe Installing the starter Kit Before beginningConnecting Starter Kit Use QCL pulse timing unit com- mand descriptionTCU151 command description TCU151 temperature controler front panelOverview Laser utilisationProceedings Starting the TPG128 Procedure Interlock utilisation Interlock utilisationTroubleshooting Power supply reaches max cur- rent for a very low voltageDC power supply is not ﬂoating PrincipleLaser draws current but gives no light Laser does not draw currentQCL laser is not used with the LLH and is grounded There is no contact with the laserHow to remove the covers of TCU151 and TPG128 MaintenanceOverview Replacement procedures Quantum Cascade Laser replace MentFacet on the case, it is extremely fragile + LLH100 connectionQCL UP and DN position Exchange Exchanging the laserIf the ambient atmosphere is humid this is HumidityTCU151 temperature con Troller interlock setting Procedure interlock settingBefore beggining interlock set Ting Needed materialCalibaration procedures Procedure calibration1 TPG128 calibration GeneralitiesTPG128 main board TPG128 main board 2 TCU151 temperature controller calibration Procedure +5V/-5V power supply checkSensing level and range adjustement = 1.22 toTemperature Reference oﬀset adjustment Current/Voltage ratio adjustment SettingOscillator check LCD screen should display 1.00 a7V = 70 C If needed, adjust it with the trimmer P92 Starting the power section of the instru Ment→ Value displayed ≤ 1A Current adjustment→ Value displayed should tend to the deﬁned value Miscellaneous functions testing Temperature Limit testing → The temperature displayed 2 should be 035 CThreshold on → The red LED 1 should turn oﬀApplication notes Detection techniquesDirect absorption Frequency modulation technique TildasPhotoacoustic detection Photoacoustic techniqueBias Circut Bias-T AppendixGeneral Utilisation What has to be kept in mind before use? Current and voltage ranges of the Bias-T cir- cuit Avoid reverse polarity on the inputUnpacking NS laser from its transportation box Unpacking instructions for NS submounts