Velocity-Matched Distributed Photodetectors and Balanced Photodetectors with p-i-n Photodiodes

We report on the first demonstration of velocity-matched distributed photodetectors and balanced photodetectors with p-i-n photodetectors. Record-high linear dc photocurrent of 45 mA has been achieved without suffering from thermal damage, thanks to the superior power handling capability of p-i-n photodiodes. A novel fiber alignment technique has been developed to achieve high linear photocurrent. More than 37 dB of common-mode-rejection ratio and 45-dB suppression of laser relative intensity noise over a broad frequency range have been achieved using the distributed balanced photodetectors in an RF fiber-optic link. The frequency response is flat from 1 to 35 GHz.