Multi-Octave Microwave Transmission Over Fiber with a Single Optical Phase Modulator

Optical phase modulators (PMs) present advantages over Mach-Zehnder intensity modulators (MZMs) for microwave signal relay applications, including lower optical loss and bias-free operation (Bucholtz et al., 2006). However, unlike quadrature-biased MZMs, PMs do not automatically suppress second-order harmonic and sum/difference frequencies, limiting their utility to suboctave signals. The authors describe recent experimental results that show suppression of second-order distortion using a single PM by adapting a previously reported technique by Haas and Murphy (2007). This development enables broadband operation of an optical PM link with a spur-free dynamic range (SFDR) as good as that of a traditional MZM-based link.