Bit error rate performance analysis of an optical MSK heterodyne/synchronous receiver

The theoretical bit-error-rate performance analysis of an optical minimum-shift-keying (MSK) heterodyne/synchronous receiver is presented, taking into account the effect of imperfect phase references. The performance of the receiver is evaluated in terms of the laser linewidth requirements, receiver sensitivity, and loop bandwidth. It is shown that an intermediate-frequency (IF) linewidth of approximately 7.6×10 ^-4 of the bit rate is required to avoid a power penalty of 1.0 dB with an RMS phase error of 0.144 rad. For a 2-Gb/s synchronous MSK, the system requires a laser linewidth of 1.52 MHz and a loop bandwidth of 348 MHz