Spontaneous Emission into Open Optical Systems
The fluctuation-dissipation theorem is used to determine the noise source for an open system with gain or loss. The noise source is projected on to the eigen-modes, which form a biorthogonal set because of the non-Hermitian character associated with gain or loss. The modes provide a flexible intuitive approach, convenient for quantization as well as for numerical calculation. This theory can be readily applied to most semiconductor lasers. The system can be inhomogeneous as in DFB lasers. Spatial variation of the index of refraction and of the gain are taken into account. Our procedure works both for longitudinal and transverse hole-burning. We apply it both below and above threshold.
KeywordsSpontaneous Emission Noise Source Injection Current Linewidth Enhancement Factor Small Signal Analysis
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