Title :
A grating-based OCDMA coding-decoding system incorporating a nonlinear optical loop mirror for improved code recognition and noise reduction
Author :
Lee, Ju Han ; Teh, Peh Chiong ; Petropoulos, Periklis ; Ibsen, Morten ; Richardson, David J.
Author_Institution :
Optoelectron. Res. Centre, Southampton Univ., UK
fDate :
1/1/2002 12:00:00 AM
Abstract :
We demonstrate an elementary grating-based optical code division multiple access (OCDMA) code generation and recognition system incorporating a nonlinear optical loop mirror (NOLM) within the receiver. We show that the NOLM can act as a nonlinear processing element capable of reducing both the pedestal associated with conventional matched filtering and the width of the associated code-recognition pulse. The pedestal rejection allows for an improved code recognition signal-to-noise ratio (SNR) relative to simple matched filtering alone, and reduced intra- and interchannel interference noise due to code overlap. The system benefits of using the NOLM are experimentally demonstrated under both single- and multiuser operation within a variety of seven- and 63-chip 160-Gchip/s code generation, recognition, and transmission experiments based on the use of bipolar superstructure fiber Bragg grating (SSFBG) coding-decoding pairs. Incorporation of the NOLM is shown to allow error-free penalty-free operation at data rates as high as 2.5 Gb/s under single-user operation, and to provide error-free performance with reduced power penalty in two-user experiments. The narrowed pulse recognition signature offers major advantages in terms of the further all-optical processing of decoded signals, such as code regeneration and recoding
Keywords :
Bragg gratings; Internet; code division multiple access; decoding; mirrors; nonlinear optics; optical fibre communication; optical receivers; telecommunication traffic; 2.5 Gbit/s; all-optical processing; bipolar superstructure fiber Bragg grating coding-decoding pairs; code generation; code overlap; code recoding; code recognition; code recognition signal-to-noise ratio; code regeneration; code transmission experiments; code-recognition pulse; data rates; decoded signals; error-free penalty-free operation; grating-based OCDMA coding-decoding system; interchannel interference noise; intrachannel interference noise; matched filtering; noise reduction; nonlinear optical loop mirror; nonlinear processing; pedestal rejection; pulse recognition signature; receiver; reduced power penalty; Fiber nonlinear optics; Filtering; Gratings; Matched filters; Mirrors; Multiaccess communication; Nonlinear optics; Optical filters; Optical receivers; Signal to noise ratio;
Journal_Title :
Lightwave Technology, Journal of