250 kHz spectral linewidth operation of 1.5 mu m multiple quantum well DFB-LDs

The spectral linewidth observed in a 1.5 mu m multiple-quantum-well distributed-feedback laser diode (MQW-DFB-LD) with 1500 mu m cavity length is discussed. The spectral linewidth was drastically reduced in long-cavity MQW-DFB0-LDs through a reduction in threshold carrier density. A spectral linewidth of 250 kHz, the narrowest ever achieved, was obtained.<
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