The response of semiconductor optical amplifiers containing lateral composition modulation in the quantum wells

Tensile strained quantum wells are used to change the polarization sensitivity of semiconductor optical amplifiers. However, lateral composition modulation (LCM), which is present in the quantum wells of the device, is shown to impact the device performance. A broadening of the spectral gain is seen as recombinations from the conduction band to the heavy hole band in the In-rich regions of the LCM. This additional component to the gain from the quantum well will reduce the device gain efficiency at a specific wavelength for a given current, or it may be used to broaden the gain spectrum of an individual quantum well.