Abstract

Optical amplifiers are a key device for future optical fiber transmission systems and have been extensively investigated. Traveling wave type semiconductor laser amplifiers (TWAs) are very attractive because high signal gain over 25 dB and high saturation output power over 10 dBm can be easily obtained. However, TWAs have an inherent problem compared with fiber amplifiers; the signal gain of the TE mode is usually larger than that of the TM mode. This is due to the mode confinement factor difference between the TE and TM modes. Various approaches to eliminate this problem have been attempted : introduction of a thick active layer^1-2) , a large optical cavity (LOC) structure³⁾, a hybrid configuration using two TWAs⁴⁾, and so on.

© 1990 Optical Society of America