Linewidth of a semiconductor laser operating near threshold

The linewidth of a single-mode semiconductor laser operating in the threshold region has been studied both theoretically and experimentally. Due to strong phase-amplitude coupling in a semiconductor laser, its linewidth versus current characteristics exhibit a local minimum below threshold and a local maximum just about threshold. This implies a limitation in the minimum optical bandwidth achievable in a resonant-type semiconductor laser optical amplifier. The theoretical prediction has been verified experimentally on a conventional DFB semiconductor laser.<
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