Measurement and modelling of high-linearity partially depleted absorber photodiode

Third-order intermodulation distortions of an InGaAs/InP partially depleted absorber photodiode (PDA-PD) using high doping levels for both p-type and n-type absorbers are characterised using a two-tone measurement technique. The third-order local intercept point (IP3) of the device increases only slightly with frequency, and remains as high as 39 dBm up to 20 GHz. The frequency characteristics of the IP3 can be well explained by an equivalent circuit model.