Abstract

A practical timing recovery subsystem for a direct detection optical communication system that uses Q=4 pulse position modulation (PPM) signaling at 25 Mb/s is described. The system consists of an AlGaAs laser diode transmitter and an avalanche photodiode (APD) photodetector. The PPM slot clock is recovered with a transition detector followed by a phase lock loop (PLL). The PPM word clock is recovered by tracking pairs of back-to-back PPM pulses in the received random PPM data sequences with another PLL. The system is capable of acquiring and maintaining slot and word synchronization at greater than 20 average detected photons per information bit (40 photons/PPM pulse). >

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

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.