Multi-octave operation of low-biased modulators by balanced detection

A balanced detection approach is proposed and demonstrated which can eliminate the single-octave constraint of performance enhancement schemes for externally modulated optical links, such as low-biasing and carrier filtering. Using our approach with low-biased modulators at 110 MHz we demonstrated a second harmonic reduction of 28 dB and a multi-octave SFDR improvement of 22 dB, to 108 dB/spl middot/Hz/sup 1/2/.