DS-OCDMA encoder/decoder performance analysis using optical low-coherence reflectometry

• Published in: Journal of lightwave technology Vol. 24; no. 8; pp. 3121 - 3128
• Main Authors: Fsaifes, I., Lepers, C., Obaton, A.-F., Gallion, P.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.08.2006; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers (IEEE)/Optical Society of America(OSA)
• Subjects: Applied sciences; Bragg gratings; Circuit properties; Coders; Coding, codes; Decoders; Decoding; Electric, optical and optoelectronic circuits; Electronics; Encoders; Engineering Sciences; Exact sciences and technology; Fiber Bragg grating (FBG); Fiber gratings; Information, signal and communications theory; Integrated optics. Optical fibers and wave guides; Length measurement; Modulation; Multiaccess communication; Optical and optoelectronic circuits; optical code-division multiple access (OCDMA); Optical fibers; optical low-coherence reflectometry (OLCR); Optical sensors; Optical telecommunications; Performance analysis; Pulse measurements; Reflectometry; Signal and communications theory; Spectra; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Wavelength measurement; Wavelengths; Performance evaluation; Integrated optics; Optical telecommunication; Wireless telecommunication; Bragg grating; Specification; Time response; Grating in fiber; Coherent detection; Fiber Bragg grating (FBG); optical low-coherence reflectometry (OLCR); Codec; Pulse response; Modulation; optical code-division multiple access (OCDMA); Code division multiple access; Measurement method; Localization; Direct sequence; Reflectance; Optical fiber
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2006.878039

Direct-sequence optical code-division multiple-access (DS-OCDMA) encoder/decoder based on sampled fiber Bragg gratings (S-FBGs) is characterized using phase-sensitive optical low-coherence reflectometry (OLCR). The OLCR technique allows localized measurements of FBG wavelength and physical length inside one S-FBG. This paper shows how the discrepancies between specifications and measurements of the different FBGs have some impact on spectral and temporal pulse responses of the OCDMA encoder/decoder. The FBG physical lengths lower than the specified ones are shown to affect the mean optical power reflected by the OCDMA encoder/decoder. The FBG wavelengths that are detuned from each other induce some modulations of S-FBG reflectivity resulting in encoder/decoder sensitivity to laser wavelength drift of the OCDMA system. Finally, highlighted by this OLCR study, some solutions to overcome limitations in performance with the S-FBG technology are suggested