Title :
Direct detection of closely spaced optical FM-FDM Gb/s microwave PSK signals
Author :
Way, W.I. ; Lo, Y.H. ; Lee, T.P. ; Lin, C.
Author_Institution :
Bellcore, Red Bank, NJ, USA
Abstract :
A modulation scheme combining microwave phase-shift-keyed (PSK) and optical frequency modulation (FM) techniques is used in a two-channel optical frequency-division-multiplexed (FDM) system. Optical filtering and FM demodulation are carried out by a tunable fiber Fabry-Perot etalon. A transmission rate of 2 Gb/s and a channel spacing of less than 30 GHz are achieved with a crosstalk level of about -25 dB. This work shows that the modulation technique of combining optical FM/FDM and RF/microwave subcarrier multiplexing is transparent to either digital or analog signals. The modulation technique not only avoids the low-frequency nonuniform FM response problem, but also facilitates close optical channel spacing.<>
Keywords :
frequency division multiplexing; frequency modulation; optical links; optical modulation; phase shift keying; signal detection; 2 Gbit/s; FM demodulation; RF/microwave subcarrier multiplexing; channel spacing; close optical channel spacing; crosstalk level; direct detection; microwave PSK signals; optical filtering; optical frequency modulation; transmission rate; tunable fiber Fabry-Perot etalon; two channel optical FDM system; Channel spacing; Frequency division multiplexing; Frequency modulation; Microwave filters; Microwave theory and techniques; Optical crosstalk; Optical filters; Optical modulation; Phase modulation; Phase shift keying;
Journal_Title :
Photonics Technology Letters, IEEE
