Laser mode partition noise in lightwave systems using dispersive optical fiber

Semiconductor laser mode partition noise (LMPN) can impair analog optical systems, but this phenomenon has not previously been well-characterized. Theoretical expressions for the noise spectra that result when light from a nearly single-mode or strongly multimode semiconductor laser is passed through a length of dispersive optical fiber are presented and have been tested experimentally. A widely used model is found to greatly overestimate the partition noise of a DFB laser; a model for the strongly multimode case is found to match experimental results for a multimode laser. It is observed that partition noise can be significant even for multimode lasers operating near the fiber dispersion minimum