PHOTODETECTOR NONLINEARITY LIMITATIONS ON A HIGH-DYNAMIC RANGE 3 GHZ FIBER OPTIC LINK

The performance of a de to 3 GHz externally modulated link utilizing b alanced high-power photodetection is presented, Nonlinearity measureme nts of high power photodiodes show 1 dB compression currents in excess of 55 mA and an output third-order intercept point of +32 to +34 dBm, These high current photodetectors permit the use of high power lasers as external modulator sources for low noise fiber optic links with on ly small degradations in the predicted link dynamic range. An external ly modulated link with a 240 mW NdYAG laser, a dual-output 4-V V-pi (d e) modulator, and balanced 100 mA total photocurrent yielded a link no ise figure from 15.5 to 17.5 dB, a spur-free dynamic range of 119.5 dB Hz(2/3), and a l-dB compression dynamic range of 168.4 dBHz.