Abstract

The random differences among the light pulses emitted by a single-mode semiconductor laser (SML) under last pseudorandom word modulation (PRWM) are crucial for the performance of optical communications systems. Timing jitter of the light pulses^1,2 has been recognized as a limiting factor in the performance of a DD/IM system modulated in the Gbit/sec range through an increase in the BER. This timing jitter leads to degrading pattern effects.³ In addition, it has been recently shown that pulse-to-pulse variations in the range of frequency chirp (chirp noise) during the modulation period also generate BER floors.⁵ Chirp noise arises from spontaneous emission noise, and its connection with timing jitter was pointed out in Ref. 4.

© 1993 Optical Society of America