Measurement and modelling of the optical power handling of wideband photodiodes

Experimental work on wideband, planar p-i-n photodiodes has shown that the 1 dB electrical compression point is good (~30 mA photo-current) at low frequencies, but is very limited (typically 5-7 mA) at high frequencies (10 GHz and above). It was found that higher bias voltage improves the compression characteristics only slightly, and only at high frequencies, but it is known that the use of higher bias voltage can cause diode failure. In experiments using a variable illumination spot size, a larger spot size was not clearly shown to improve compression, although this should be the case. Before better performance can be demonstrated one must understand the behaviour observed, and thus make the necessary changes to photodiode design or operation, and thus understanding should be gained through the use of a 1-D computer model, which has already shown a promising degree of accuracy in predicting experimental results