Low loss nearly square-section multi-bulk-layer lasers for polarization insensitive optical amplifiers

A laser structure having an active layer composed of several thin bulk layers is described. Buried ridge structure type Fabry-Perot lasers fabricated by using this structure exhibit a low internal loss of 15.6 cm/sup -1/ and a RC-limited modulation bandwidth as wide as 10 GHz. A reduced polarization sensitivity was demonstrated by a test optical amplifier. >