Abstract

Semiconductor laser amplifiers are hybrid nonlinear optical devices which offer the advantages of extremely low optical switching energies, low total energy consumption, high gain, and wavelength compatibility with diode laser sources. We have demonstrated optical switching in a Fabry-Perot amplifier. The switch-on and switch-off occur in less than a nanosecond, with optical input powers of about a microwatt. This corresponds to <7000 photons input to the device. Optical gain has been measured in excess of 20 dB. The observed switching results from a change in the index of refraction of the order of 10⁻⁴. The index change arises from a decrease in carrier concentration resulting from stimulated recombination. For a given change in the refractive index, the phase shift in a nonlinear etalon is proportional to the cavity length. In a passive device, long cavity lengths are precluded by absorptive losses. In the active device discussed here, a long cavity results in greater gain and low switching power.

© 1985 Optical Society of America