Nonlinear distortion of Fabry-Perot optical filters in direct modulated dense WDM-SCM video distribution systems

摘要

Fabry-Perot-type optical filters (FPFs) are found to induce nonlinear distortion in dense wavelength division multiplexing with subcarrier multiplexing (WDM-SCM) analog video distribution systems. An analysis of the distortion caused by the interaction of filter transmittance tilt with chirped laser light determines that second-order distortion, which is greatly influenced by filter detuning shift and phase difference between IM and FM parts of the laser light, can be eliminated when the phase difference is 0 or pi , and wavelength displacement between LD output and the FPF is equal to one-half the laser chirp parameter. Transmission experiments using 40-channel AM-FDM video signals support these statements.