Narrow linewidth characteristic of a 1.5 mu m wavelength single-mode phase-locked laser array

The linewidth of a 1.5- mu m wavelength single-mode phase-locked laser array was measured. A relatively narrow linewidth of 203 kHz was obtained at an output power of 25 mW for a five-element phase-locked laser array that consists of a five-pair Ga/sub 0.3/In/sub 0.7/As/GaInAsP/InP compressively strained quantum-well active region and a mode controlling grating filter. This result indicates the reduced spontaneous emission factor due to a larger cavity size in the lateral direction.<
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