A novel analytical expression of sensitivity to external optical feedback for DFB semiconductor lasers

A novel analytical expression for DFB laser sensitivity to external optical feedback is derived based on coupled-wave theory. The expression reveals that the sensitivity is proportional to the ratio between the output power from the reflector-side facet and the magnitude of Lagrangian of the electromagnetic field in the cavity. The simplicity of the expression helps in estimating the sensitivity of DFB lasers with complex cavity structures.<
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