Abstract

In quantum well lasers, a separate confinement heterostructure is usually used to obtain a quantum confinement of the injected carriers in the active region and a confinement of the optical field in the waveguide. It is shown that the appreciable carrier population in the electronics states of the optical confinement layers (state filling effect) has a large influence on the differential gain in the quantum well lasers. By using different separate confinement structures for quantum well lasers, we find experimentally that the differential gain difference can be as large as a factor of three, which significantly affects the high speed modulation bandwidth in such lasers. These experimental results agree well with the theoretical predictions.

© 1992 Optical Society of America