Reports until 17:17, Thursday 30 November 2023
Electronics General (GQuEST)
Alex Ramirez - posted 17:17, Thursday 30 November 2023 (11390)
APD Updates

Now that i have organized the EE lab space a bit more (img1), things have been flowing well to get the thorlabs APD (FGA015) setup and working with my circuits.

A majority of the schematic from the homodyne photodiode board were used and adapted for this APD (they both run at 5V and have some similar specs). This has shown and proven the usefullness of a few of my circuits I will be using for the Encilitas APD eventually. Bellow I have some images that show the LED being turned on and shined on a IR Card (img 2), the signal from the APD (img 3), the noisy APD signal with the LED turned off (im 4). The overall circuit setup can then be seen (img 5).

In the setup, the LED is being powered at a reasonably low voltage and also has an ND filter infront of it (NDIR30A). I am also just using a single power supply. To regulate +-15 V for the op amps and a +5V reference being used by the APD and LED. Once I get a hang of the APD signal, I will utilize a waveform generator to pulse the LED to take measruements and at somepoint swap to characterizing it using the Yokogawa setup in Boris' lab. 

First, l will use the Basler camera and power meters to calibrate the camera to and understand its dark count rate and sensitivity. I will then use this to cross check my results from the APD. 

Images attached to this report