Dynamic range of DFB semiconductor lasers

Summary form only given. For high-fidelity, narrowband applications such as radar and microcellular PCS, the important figure of merit is the spurious free dynamic range, which is determined by the largest input RF power for which the intermodulation distortion is below the system noise floor. Modeling the dynamic range of a directly modulated laser requires a high-frequency model of the signal distortion as well as a model for the intensity noise in the laser. This paper presents the first such theoretical analysis of dynamic range in a distributed feedback (DFB) laser. The model is used to analyze the performance of an experimental UHF link and to determine an optimized device design. Spatially distributed rate equations based on the Green´s function method are used to model the nonlinear response and noise of an index-coupled DFB laser. The noise power spectra are determined by introducing the Langevin noise sources into the rate equations. In this way, closed-form expressions for the intermodulation distortion and noise floor can be obtained; this facilitates efficient numerical simulation of DFB performance.