Photodiode measurements

Discussion in 'The Projects Forum' started by Dr. Arun Joglekar, Dec 3, 2009.

  1. Dr. Arun Joglekar

    Thread Starter New Member

    Dec 1, 2009
    I recently purchased from a US supplier InGaAs photodiodes PINTIA with built-in transimpedance pre amp(150MH bandwidth). The supplier spec sheet says if I supply 5V across 2 specified leads I will get about 3.V output on the other 2 leads(inverting and non-inverting) after I attach 1mW 1550nm laser diode to the PIN TIA. But I am not measuring anything.

    What may have gone wrong? I took care in soldering time and ESD.
    How do I check if the diode is damaged? Do I need to do anything further such as attching a load resistor?

    Arun Joglekar
  2. mik3

    Senior Member

    Feb 4, 2008
    Can you post the datasheet of the diodes?
  3. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    Are you trying to drive the input of the laser diode with the output of the photodiode preamp? The preamp may not have enough power to drive the laser diode.

    If you remove the connections between the two diodes, do you see the common mode ~ 3 volts on the photodiode signal pins? Do you see any signal changes if you shine the appropriate light into the photodiode after the diodes are disconnected?

    Also, what type of signals is the laser diode expecting?

    I am no expert in this field but these are just some initial questions that may help move your project along.