Laser noise considerations for phase modulated links

摘要

Photonic links employing intensity modulation with direct detection are typically unaffected by laser phase noise without a mechanism to convert that phase noise into intensity noise. Such mechanisms in long links include chromatic dispersion and double-Rayleigh scattering, the latter of which introduces multi-path interference (MPI). However, these processes are generally not a concern in short links for avionic platforms except when reflections from fiber optic connectors produce strong MPI. Phase modulated links provide distinct advantages over intensity modulation for digital [1] and analog [2] applications; however, they are severely impacted by laser phase noise. Here we describe considerations for a phase modulated link employing an asymmetric Mach-Zehnder interferometer (MZI).