Measuring the frequency response of gigabit chip photodiodes

We describe a calibration and measurement procedure for determining the intrinsic frequency response of gigabit chip photodiodes embedded in simple test fixtures. The procedure is unique because we make the measurements in the time domain using a calibrated oscilloscope, and we then apply frequency-domain mismatch corrections to remove the effects of the fixture, bias T, and cables from the measurements. We demonstrate the procedure on photodiodes with an active region of approximately 150-mum diameter excited by short 800-nm wavelength optical pulses.