In this paper,analog signal with 0.1 to 10 GHz frequencies,digital signal with 0.2 and 0.3 Gbit/s rates and frequency shift keying decoding are studied in chaotic lasers.Influences of the frequency and the amplitude of the encoded signals and rate limit of chaotic shift key of lasers on synchronous error are optimally analyzed.Full_synchronization and pseudo_synchronization are discussed.Optimum of the effects of the parameter mismatch and the feedback coefficient on synchronous error and synchronous time is also discussed.