Datasheet

Contents
1 Mechanical and geometrical properties 3
1.1 Geometry of QC lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.1 How are the axes of the laser defined, i.e. what is vertical? . . . . . . . . . . . . . 3
1.1.2 What are the physical dimensions of laser carriers? . . . . . . . . . . . . . . . . . 4
1.1.3 What materials are used for the laser carriers? . . . . . . . . . . . . . . . . . . . . 4
1.2 How to handle a QCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2.1 How do I store a QCL? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2.2 How do I handle (carry) a QCL? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2.3 How to mount a QCL in an optical setup . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2.4 Soldering wires to submount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Electrical and optical properties 7
2.1 Electrical limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1.1 What is the maximum allowed duty cycle? . . . . . . . . . . . . . . . . . . . . . . . 7
2.1.2 What happens if I increase the duty cycle? . . . . . . . . . . . . . . . . . . . . . . 7
2.1.3 What is the lifetime of the laser (MTBF)? . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 Electrical properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.1 What impedance does a QCL show? . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.2 Can I check the impedance with an ohm-meter? . . . . . . . . . . . . . . . . . . . 8
2.2.3 Where is the cathode of a QCL? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.4 How do I drive a pulsed QCL? Can I use a standard laser driver? . . . . . . . . . . 8
2.2.5 How do I drive a CW QCL? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3 Optical properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3.1 Mode characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3.2 What is the polarisation of the emitted mode? . . . . . . . . . . . . . . . . . . . . . 10
2.3.3 How do I collimate the beam? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3.4 How do I calculate the radiance? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3 Starter Kit (pulser, temperature controller, etc...) 11
3.1 Operation of TE cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.1.1 What is the dissipated heat of a pulsed QC laser? . . . . . . . . . . . . . . . . . . 11
3.1.2 What temperatures can be reached with the TCU-151? . . . . . . . . . . . . . . . 11
3.2 Important points concerning LDD pulsers . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2.1 What are the possible pulse lengths and duty cycles? . . . . . . . . . . . . . . . . 11
3.2.2 What is the ”external power supply” used for? . . . . . . . . . . . . . . . . . . . . 12
3.3 Low-impedance line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.3.1 How to connect the low-impedance line . . . . . . . . . . . . . . . . . . . . . . . . 12
3.4 Low-frequency bias current for modulation . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.4.1 What are function and purpose of a bias-T circuit? . . . . . . . . . . . . . . . . . . 12
3.4.2 What are the connections of the bias-T circuit? . . . . . . . . . . . . . . . . . . . . 13
3.4.3 Dangers and disadvantages of using a bias-T circuit . . . . . . . . . . . . . . . . . 13
3.4.4 What has to be kept in mind before use? . . . . . . . . . . . . . . . . . . . . . . . 13
3.4.5 What are the current and voltage ranges of the bias-T circuit? . . . . . . . . . . . 14
3.5 Laser Laboratory Housing (LLH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.5.1 What is the distance of the laser die output facet from the window external facet? . 14
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