Interferometric modulation in an optical amplifier based on an InGaAsP/lnP heterostructure

Optical amplifiers made of laser diodes can be used as fast switches and modulators of the transmitted light. An "interferometric" modulation variant is interesting in this application: a part of the input radiation propagates along a passive emitter layer and interferes at the output with a part transmitted by an amplifying region. An optical amplifier operating in the 1.3-μm range made of an InGaAsP/lnP heterostructure is used as an example to show that such an interferometric variant can be used to achieve separately amplitude and phase modulation, and to increase the slope of the amplitude characteristic.