I am trying to use the AD8015 for a visible light communication application. For the moment, I am simply transmitting a square light signal at 1 MHz that I receive with a Hamamatsu S3590 photodiode, which has a large juction capacitance. The photodiode is reverse biased at -5V, as shown on the schematic enclosed. Then I am observing the ouput signal given by PIN 7. The resulting trace is also enclosed and shows that the output signal is indeed a square wave (here at 500 kHz, recorded in a dark room) but never returns to around 0 V as it should when the transmit light is off.
I am sure the device is not connected properly but I can't really know what to do.
Thank you advance for your aswers.