Quantum Instruments Cascade Laser Starter Kit manual QCL pulser switching unitLDD100

Page 21

Starter Kit Instruction Manual

Description

20

4.5QCL pulser switching unit(LDD100)

4.5.1Description

The switching unit is based on dedicated power MOS-FETS with up to 30A current compatibilities and 60V. In addition, the circuit is limited in power dissipation by the cooling of the unit. During op- eration, the temperature of the case should not ex- ceed 60C. While powering usual QC diodes, these limitations are never reached because the laser has usually much lower power ratings.

! WARNING !

An important feature of this unit is that both lines going to the laser are ”HOT”, i.e. have a postive voltage respective to the case. this feature should be kept in mind when de- signing the laser holder. This one should be insulated and have a low capacitance(< 100pF) towards the ground.

The QCL pulse switching unit is composed of the following connectors:

(1)Low impedance connector

(2)Drive cable connector

(3)Monitoring BNC connector

4.5.2Speciﬁcations

Voltage : . . . . . . . . . . . . . . . . . . . . . . max 60 VDC

Current : . . . . . . . . . . . . . . . . . . . . . . max 30 ADC

Repetition rate : . . . . . upto 1MHz, limited by average current

Rising/falling edge: . . typical 8ns (max 12ns)

Minimum pulse width: . . . . 16ns, typical 20ns

Maximum pulse width: 1µs, limited by power supply

Support power: . . . . . . . . . . . . given by TPG128

Trigger IN: . . . . . . . . . . . . . . . . . . . . . . . . TTL 50Ω

Propagation delay: . . . . . . typical 35ns <40 ns

Size: . . . . . . . . . . . . . . . . . . . . . 90 x 130 x 50 mm3

! WARNING !

The connection between the laser and the QCL pulse switching unit is ﬂoating. It must not be connected with the ground.

2

3

Z50

Ohm

A/V,

20

Input

12V

60V

Monitor

supply

Max

Power

control

Voltage

Current

High

hi +

Bottom

to

top, on

Output

Pulseconnected

LDD

100

1

Fig.9: QCL pulser switching unit front and rear view

Image 21

Contents Instructions Manual Web version Quantum Cascade Laser Starter KitContents Troubleshooting InstallationMaintenance Overview UseAppendix Document IdentiﬁcationLimited waranty ManufacturerChapter overview GeneralGeneralities CompliancePersons GlossaryProduct PersonnelProcedure style Commands styleTypographic conventions Description styleProcedure eﬀects style ProblemSee page x-y Troubleshooting style Possible causePage Importance of safety instructions Safety InstructionsNon-compliance with the safety regulations IntroductionGeneral safety instructions Environmental conditionsCompliance and informa- tion System Composition DescriptionIf no conﬁguration is speciﬁed, the DN pad is used DFB and FP Quantum Cascade LasersDescription Geometry of QC lasersSpeciﬁcations Electrical model Electrical model characteristicsLLH100 external view description Laboratory Laser HousingLLH100LLH100 internal view Laboratory Laser Housing internal viewThermo-Electric Cooler TEC and PT100 connections Speciﬁcations of the Peltier connectorMeasurement connection Speciﬁcations of the measurement connectorQCL pulser switching unit front and rear view QCL pulser switching unitLDD100Generalities QCL pulse switching measuring unitMeasured voltages Timing dataDuty cycle calculation Laser peak currentLaser peak voltage Average dissipationAccuracy considerations QCL pulser timing unit TPG128 Trigger and logic output signals Ω TTL driver circuitPeltier and PT100 connections QCL temperature controllerTCU151Chapter overview Packing list InstallationGeneral Standard itemsSetting the appropriate AC voltage on TCU151 Procedure110-120V, 60Hz USA 220-240V, 50Hz Europe Before beginning Installing the starter KitConnecting Starter Kit QCL pulse timing unit com- mand description UseTCU151 temperature controler front panel TCU151 command descriptionLaser utilisation OverviewProceedings Starting the TPG128 Interlock utilisation Procedure Interlock utilisationPower supply reaches max cur- rent for a very low voltage TroubleshootingDC power supply is not ﬂoating PrincipleLaser does not draw current Laser draws current but gives no lightQCL laser is not used with the LLH and is grounded There is no contact with the laserMaintenance How to remove the covers of TCU151 and TPG128Overview Quantum Cascade Laser replace Ment Replacement procedures+ LLH100 connection Facet on the case, it is extremely fragileExchanging the laser QCL UP and DN position ExchangeHumidity If the ambient atmosphere is humid this isProcedure interlock setting TCU151 temperature con Troller interlock settingBefore beggining interlock set Ting Needed materialProcedure calibration Calibaration procedures1 TPG128 calibration GeneralitiesTPG128 main board TPG128 main board Procedure +5V/-5V power supply check 2 TCU151 temperature controller calibration= 1.22 to Sensing level and range adjustementTemperature Reference oﬀset adjustment Setting Current/Voltage ratio adjustmentOscillator check LCD screen should display 1.00 aStarting the power section of the instru Ment 7V = 70 C If needed, adjust it with the trimmer P92Current adjustment → Value displayed ≤ 1A→ Value displayed should tend to the deﬁned value → The temperature displayed 2 should be 035 C Miscellaneous functions testing Temperature Limit testingThreshold on → The red LED 1 should turn oﬀDetection techniques Application notesDirect absorption Frequency modulation technique TildasPhotoacoustic technique Photoacoustic detectionAppendix Bias Circut Bias-TGeneral 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- cuitUnpacking instructions for NS submounts Unpacking NS laser from its transportation box