Accurate model of the semiconductor laser nonuniform FM response for the study of coherent optical systems

This paper proposes an accurate simulation model of the semiconductor laser nonuniform FM response, to be used in the computer-aided design of coherent optical communication systems. The FM response of the laser is modeled as a recursive digital filter derived directly from measurements. Least squares fitting and the impulse invariant transformation method are used to calculate digital filter coefficients. The procedure is applied in the case of a conventional DFB laser. The calculated model of the DFB is used to study the influence of the nonuniform FM response on the performance of a coherent heterodyne CPFSK system with differential receiver operating at 1 Gb/s. Theoretical and experimental results are in excellent agreement.<
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