We experimentally demonstrated linewidth-tolerant 10-Gbit/s (2.5-Gsymbol/s) 16-quadrature amplitude modulation (QAM) by using a distributed-feedback laser diode (DFB-LD) with a linewidth of 30 MHz. Error-free operation, a bit-error rate (BER) of <10(-9) was achieved in transmission over 120 km of standard single mode fiber (SSMF) without any dispersion compensation. The phase-noise canceling capability provided by a pilot-carrier and standard electronic pre-equalization to suppress inter-symbol interference (ISI) gave clear 16-QAM constellations and floor-less BER characteristics. We evaluated the BER characteristics by real-time measurement of six (three different thresholds for each I- and Q-component) symbol error rates (SERs) with simultaneous constellation observation.
t He is currently with NTT ABSTRACT This paper proposes automatic repeat request (ARQ) protocols combined with an adaptive modulation system(AMS) (ARQ/AMS) to achieve high throughput data transmission for wireless multimedia communication services. First, this paper analyses the cause of throughput limitation of the conventional fixed modulation ARQ system, and discuss basic strategies to improve throughput performance by effectively combining ARQ and AMs. Next, this paper proposes a selective repeat ARQ (SR-ARQ) with A M s (SR-ARQIAMS), and shows its throughput performance improvement effect. Finally, this paper proposes a type-I1 hybrid ARQ with a punctured convolutional coding combined with the AMs (type4 hybrid ARQ/AMS) to further improve throughput performance. Computer simulation confirms that the proposed type-I1 hybrid ARQ/AMS can achieve higher throughput performances than the conventional selective repeat ARQ with QPSK under any channel conditions.
Abstract:We review work on self-homodyne detection (SHD) for optical communication systems. SHD uses a transmitted pilot-tone (PT), originating from the transmitter laser, to exploit phase noise cancellation at a coherent receiver and to enable transmitter linewidth tolerance and potential energy savings. We give an overview of SHD performance, outlining the key contributors to the optical signal-to-noise ratio penalty compared to equivalent intradyne systems, and summarize the advantages, differences and similarities between schemes using polarization-division multiplexed PTs (PDM-SHD) and those using space-division multiplexed PTs (SDM-SHD). For PDM-SHD, we review the extensive work on the transmission of advanced modulation formats and techniques to minimize the trade-off with spectral efficiency, as well as recent work on digital SHD, where the SHD receiver is combined with an polarization-diversity ID front-end receiver to provide both polarization and modulation format alignment. We then focus on SDM-SHD systems, describing experimental results using multi-core fibers (MCFs) with up to 19 cores, including high capacity transmission with broad-linewidth lasers and experiments incorporating SDM-SHD in networking. Additionally, we discuss the requirement for polarization tracking of the PTs at the receiver and path length alignment and review some
OPEN ACCESSPhotonics 2014, 1 111 variants of SHD before outlining the future challenges of self-homodyne optical transmission and gaps in current knowledge.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.