Abstract
A detailed theoretical analysis is given for the impact of finite frequency deviation on the sensitivity of dual-filter heterodyne frequency shift keying (FSK) lightwave systems. Our analysis provides closed-form signal-to-noise ratio (SNR) results for estimating the bit-error- ratio (BER) performance of the system. These closed-form results provide an insight into the impact of finite frequency deviation 2(Delta) fd, laser linewidth (Delta) (nu) , bit rate Rb, and IF filter bandwidths on the system performance. Simulation results indicate that the accuracy of the approximate theory presented in this paper is within 1 dB for linewidths up to 22% when BER equals 10-9. It is shown that there is a well-defined relationship between the choice of frequency deviation and the tolerable amount of laser phase noise. When there is no phase noise, a frequency deviation of 2(Delta) fd equals 0.72 Rb is sufficient for 1 dB sensitivity penalty with respect to infinite frequency deviation case; whereas for a linewidth of (Delta) (nu) equals 0.50 Rb the required frequency deviation increases to 2(Delta) fd equals 3.42 Rb for the same sensitivity penalty. The sensitivity degradation can be very severe for a fixed linewidth as the frequency deviation gets smaller: for a linewidth of 20% the sensitivity penalty is only 0.54 dB when the frequency deviation is infinite whereas it is 3.48 dB when the frequency deviation is 2(Delta) fd equals Rb.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call