Noise study of low-dimensional quantum-well semiconductor laser amplifiers

Low noise characteristics of semiconductor laser amplifiers (SLAs) consisting of low-dimensional quantum-well structures are obtained theoretically using density matrix theory. Due to a sharper gain spectrum as well as a smaller population inversion parameter in quantum-wire and quantum-box structures, predominant two beat noises of traveling-wave SLAs were found to be reduced in the lower dimensional quantum-well structures, even in solitary devices without a narrow bandpass filter. The noise figure can be reduced to 3.3 dB in a quantum-box structure, which nears the theoretical limit of 3 dB.<
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