Abstract

Recently, there have been several efforts to build optical heterodyne detection systems in the Gbit/s range.1–3 However, it is becoming difficult to achieve high receiver sensitivity in this range, because the heterodyne receiver requires a broad IF bandwidth. An optical quadriphase shift keying (QPSK) heterodyne system can achieve the same receiver sensitivity as the biphase shift keying (BPSK) system, requiring a half-bandwidth of the BPSK system. Therefore, the QPSK system has advantages in the Gbit/s range. The key factors, modulation method, and linewidth requirement for a QPSK coherent detection system are discussed. The feasibility of a Gbit/s range QPSK system with external cavity LDs was confirmed through theoretical calculation and the simulation experiment.

© 1988 Optical Society of America

PDF Article

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription