Patent ID: 7995929

Claim:
An optical data receiver comprising: an optical input for receiving optical data signals, the optical data signals being generated by a phase modulator that is driven between zero and less than 180 degrees such that the optical data signals have a small carrier component; first and second receiver arms; an optical splitter for splitting optical signals from the optical input into the first and second receiver arms; an optical filter in the first receiver arm for extracting the carrier component of the optical signal; means for increasing an intensity ratio of optical signal strength of the carrier component in the first receiver arm to optical signal strength of the optical signal in the second receiver arm; means for adjusting a phase difference between the first and second receiver arms; an optical coupler for coupling outputs of the first and second receiver arms to generate a modified optical signal in which the carrier component has a higher intensity ratio than the carrier component in the optical data signal that was received at the optical input; and a photo detector coupled to the optical coupler for directly detecting the modified optical signal.