Impact of apodised linearly chirped fibre gratings on the performance of dispersion-limited subcarrier systems

In the paper, the authors investigate the impact of apodised linearly chirped fibre gratings on the performance of broadband dispersion-limited subcarrier-multiplexed (SCM) microwave systems. The impairment of both nonlinear distortion and intensity noise, arising from fibre dispersion on the performance of a 20 channel FSK-microwave subcarrier system, has been analysed. To reduce both types of dispersion-induced degradation, apodised linearly chirped gratings have been employed as dispersion compensators. A simulation study for attaining the optimum parameters of the equaliser, depending on the SCM system parameters, has been carried out. The simulation results of the system performance, in terms of the bit-error rate (BER) and the carrier-to-noise ratio (CNR), reveal that dispersion-induced impairment can be sharply mitigated by using apodised linearly chirped gratings whose length 3L_g, where L_g is the minimum length to achieve dispersion compensation as obtained from theoretical derivations