Measurements of noise levels with semiconductor lasers and long lengths of polarization-preserving fiber, as used in typical linear modulator systems, show noise levels that are ~ 10 dB above thermal noise because of laser phase-to-intensity noise conversion. Data are presented for several launching angles into both polarization-preserving and polarizing fiber. There is good agreement with theory for the variation in noise with an output analyzer angle. To reduce the noise either a single frequency source must be used or the polarization-preserving fiber must be replaced by a conventional single-mode fiber.
© 1992 Optical Society of America
C. H. Bulmer, R. P. Moeller, and W. K. Burns, "Effect of phase noise in linear modulator systems," Appl. Opt. 31, 6437-6440 (1992)