Journal of optical communications 

About: Journal of optical communications is an academic journal published by De Gruyter. The journal publishes majorly in the area(s): Optical fiber & Wavelength-division multiplexing. It has an ISSN identifier of 0173-4911. Over the lifetime, 2266 publications have been published receiving 13439 citations. The journal is also known as: Journal of optical communications (Print).

Stimulated Brillouin Scattering in Monomode Optical Fiber

Abstract: Stimulated Brillouin Scattering (SBS) has recently been observed in low-loss monomode fibers at power levels of only a few milliwatts. This article reviews the increasingly important influence which SBS will have on the design and operating range of future optical communications systems which employ low-loss fiber and narrowband laser transmitters. The important dependence of the SBS gain and threshold on the spectrum and modulation parameters of the optical transmitter is described. Possible techniques for suppressing SBS in optical communications systems are discussed.

Semiconductor Laser Amplifier for Single Mode Optical Fiber Communications

Abstract: The recent advent of very low loss single mode optical fibers (< 0.2 dB/km at the 1.55μπι wavelength) opens the possibility for very long distance, high information bandwidth (^1 Gbit/s) communication systems, as transoceanic cable links or trunk networks. With such fibers, especially when chromatic dispersion is negligible, the range is only limited by attenuation, so there would be no need for complete signal regeneration (pulse shaping, timing, etc...). In these conditions, direct light amplifiers would be very attractive as \"on-line\" amplifiers as an alternative to sophisticated optoelectronic repeaters; they could also be used in a receiver as low noise preamplifiers, in combination with a pinphotodiode, especially at the 1.3 ... 1.55 μη wavelength, where avalanche photodiodes (APD) are more \"noisy\" than silicon APDs. It is our purpose to discuss the possibility for semiconductor laser amplifiers to be used in a single mode fiber communication system. We shall first derive the power budget improvement due to the insertion of a laser amplifier in a digital optical communication system. A review of semiconductor laser amplifiers (SCLA) characteristics of the traveling-wave type (TW), Fabry-Perot type (FP) and injection locked laser type (ILL) will then be presented, with emphasis on recent experimental results. Finally, possible applications of these devices in single mode fiber communication systems will be discussed. 2 Noise characteristics of a laser amplifier in an optical communication system

Impact of Laser Phase Noise on Optical Heterodyne Communication Systems

Abstract: The impact of laser phase noise on optical heterodyne communications receivers is analyzed in terms of the system signal-to-noise ratios and error rates. An ASK receiver, three FSK receivers and a DPSK receiver are investigated. The maximum permissible laser linewidth Δν is evaluated for each of these receivers and compared with previously published theoretical and experimental results. It is shown that Δν depends on the system data rate R and on the modulation/demodulation technique chosen. For example, DPSK receivers require at least Δν ^ 0.7% of R while FSK receivers with postdetection frequency discrimination require at least Δν ^ 1.9% of R if the mark-space separation 2 fd is equal to R. At the same time, ASK receivers with envelope postdetection processing, and FSK receivers with large frequency deviation are much more tolerant to phase noise: they only require Av<9%ofR.

Computation of Bit-Error Rate of Various Heterodyne and Coherent-Type Optical Communication Schemes

Abstract: The receiver sensitivity in optical communication is improved by heterodyne and/or coherent communication schemes, as compared with an ordinary intensity-modulation/direct-detection system. This paper presents the computation of the minimum signal level for achieving a prescribed bit-error rate in various heterodyne and coherent-type optical communication systems, as functions of the information-transmission rate and mixerdiode parameters. It is shown that in long-wavelength (1.3 um ~ 1.6 urn) region, the improvement in the signal level by the heterodyne/coherent schemes is relatively high (10 dB-20 dB). improvement of the receiver sensitivity especially at the longer wavelengths, because these schemes bring forth a sensitivity close to the shot-noise limit, regardless the mixer-noise performance [1]. The improvement of the sensitivity by these schemes was first computed by Yamamoto [2], who gave the BER vs. signal-power relations for various heterodyne/coherent schemes.

Distributed Feedback Laser (DFB) for Signal Power Amplitude Level Improvement in Long Spectral Band

Abstract: This study outlines the distributed feedback laser for signal power amplitude level improvement in the long spectral band of 1550 nm wavelength within supporting pumped wavelength of 1480 nm. The bias and modulation peak currents based distributed feedback laser are varied in order to test the signal power level, peak signal amplitude variations after the fiber-optic channel and light detectors. The signal power level, peak signal amplitude is measured against spectral wavelength and time bit period variations. The study emphasis the signal power level, peak signal amplitude are enhanced for the best selection values of both a bias current at 45 mA and modulation peak current at 0.5 mA.