1,721,593 research outputs found
Pulsed-incoherent-light-injected Fabry-Perot laser diode for WDM passive optical networks
Full text linkWe propose and demonstrate a pulsed-incoherent-light-injected Fabry-Perot laser diode (FP-LD) which generates incoherent return-to-zero (RZ) signals for wavelength-division-multiplexing passive optical networks. For the generation of the RZ signals, we first convert the continuous-wave (CW) amplified spontaneous emission (ASE) into an ASE pulse train with a pulse carver, spectrum-slice it into multiple channels with a waveguide grating router, and then inject them into FP-LDs for data modulation. Thanks to a wide slicing bandwidth of the injected incoherent light, the spectral linewidth of the generated RZ signals is determined by the slicing bandwidth, without being affected by the use of the RZ format. Thus, compared to incoherent non-return-to-zero (NRZ) signals generated with CW-ASE-injected FP-LDs, the RZ signals have a similar spectral linewidth but a wide timing margin between adjacent bits. Thus, the proposed transmitter can offer better dispersion tolerance than the NRZ signals. For example, our experimental demonstration performed at 1.25 Gb/s shows similar to 50% higher dispersion tolerance than the NRZ signals generated with CW ASE-injected FP-LDs. Despite the large slicing bandwidth of 0.67 nm for the injected ASE, we were able to transmit 1.25-Gb/s signals over 45-km standard single-mode fiber without dispersion compensation. The receiver sensitivity is also improved by 1.5 dB by using the RZ format. (C) 2010 Optical Society of Americ
Cross-phase-modulation-induced nonlinear phase noise in WDM direct-detection DPSK systems
No full textIn direct-detection differential-phase-shift-keying (DPSK) systems, the signed-spontaneous emission beat noise introduces phase noise due to Kerr nonlinearity. In wave-length-division-multiplexed (WDM) systems, this nonlinear phase noise comes not only from the channel itself through self-phase modulation (SPM) but also from the other channels through cross-phase modulation (XPM). In this paper, we theoretically and experimentally investigate XPM-induced nonlinear phase noise. We calculate the performance degradation of DPSK systems caused by XPM-induced nonlinear phase noise in addition to SPM-induced phase noise and experimentally verify it using a 600-km nonzero-dispersion-shifted-fiber link
RoF-based optical fronthaul technology for 5G and beyond
No full textWe explore the possibility of using directly modulated laser for the implementation of mobile fronthaul networks based on the RoF technology. The deleterious effects arising from laser's chirp are investigated together with their compensation techniques
EML-based optical single sideband transmitter
No full textWe present a novel optical single sideband (SSB) transmitter comprised of an electroabsorption modulated laser. The transmitter exploits the hybrid or compatible SSB structure wherein the directly modulated laser diode and the electroabsorption modulator function as phase and amplitude modulators, respectively. The theoretical analysis and experimental demonstration confirm the feasibility of optical SSB transmitter for radio-over-fiber applications by using this small semiconductor device
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