o Purpose of the measurement
- Test Si QPDs (C30845EH) for ISC QPDs Qty 30 (i.e. 120 elements)
- Test InGaAs PDs (C30665GH) for OMC Qty 10 (i.e. 10 elements)
o Measurement Kit
- Inherited from Frank.
- Has relays in it.
- D0 and D1 switches the measurement instrument connected to an element
- D2 and D3 switches the element of the QPDs
- Digital switch summary
d0 d1 0 0 - ln preamp
d0 d1 1 0 - dark c
d0 d1 0 1 - omc preamp
d0 d1 1 1 - impedance
d2 d3 0 0 - A x x x
d2 d3 1 0 - C x o x
d2 d3 0 1 - B o x o
d2 d3 1 1 - D o o o
- The universal board in the box is currently configured for C30845.
Pin1 - Elem A. Pin3 - B, Pin7 - C, Pin9 - D, Pin 12 - Case&Bias
o Labview interface
- Controls NI-USB-6009 USB DAQ interface and Agilent 82357B USB-GPIB interface
o Dark current measurement
- Borrowed Peter's source meter KEITHLEY 2635A
- For C30845GH the maxmum reverse bias is set to -20V. This drops the voltage of the each element to the bias voltage.
o Spectrum measurement
- The elements are connected to FEMTO LN current amp DLPCA-200.
- Bias voltage is set to +10V. This lifts up the outside of the amplifier input to +10V.
o Impedance measurement
- Agilent 4395A at PSL lab with impedance measurement kit
- For C30845GH the maxmum reverse bias is set to -15V. This drops the voltage of the each element to the bias voltage.
- Calibration: open - unplug the diode from the socket, short - use a piece of resister lead, 50Ohm - a thin metal resister 51Ohm
- Freq range: 30-50MHz where the response of the cables in the setup is mostly flat.
- Labview VI is configured to read the equivalent circuit parameters in the configuration "D" (series LCR).
- Labview fails to read the series resistance. This was solved by first read the equiv circuit param and then read it with Sim F-CHRST.
F-CHRST does nothing on the parameters so the second request successfully acquires the first ones.