Downstream Differential Phase Shift Keying Research Articles

Wavelength division multiplexing passive optical networks (WDM PONs) With Downstream DPSK and Upstream Remodulated OOK using Injection-Locked Fabry-Perot Laser Diodes (FP-LDs)

Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) system based on the injection locked Fabry-Perot laser diode (FP-LD) has been investigated. The system has been demonstrated without dispersion compensation for both 10Gbps Differential phase-shift keying (DPSK) downstream signal and 2.5Gbps On-off keying (OOK) upstream signal respectively. Error free transmission over 50-km is achieved by tailoring the parameters of the FP-LD. The BER performance of our system shows that the injection locked FP-LD is a low cost effective colourless transmitter for high-speed WDM-PONs. Full Text: PDF References E. Wong, "Next-Generation Broadband Access Networks and Technologies", J. Lightwave Technol. 30(4), 597 (2012). CrossRef F.T. An, D. Gutierrez, K.S. Kim, J.W. Lee, L.G. Kazovsky, "SUCCESS-HPON: A next-generation optical access architecture for smooth migration from TDM-PON to WDM-PON", IEEE Commun. Mag. 43(11), S40 (2005). CrossRef S.-J. Park, C.-H. Lee, K.-T. Jeong, H.-J. Park, J.-G. Ahn, K.-H. Song, "Fiber-to-the-home services based on wavelength-division-multiplexing passive optical network", J. Lightwave Technol. 22, 2582 (2004). CrossRef C.W. Chow, C.H. Yeh, "Using Downstream DPSK and Upstream Wavelength-Shifted ASK for Rayleigh Backscattering Mitigation in TDM-PON to WDM-PON Migration Scheme", IEEE Photon. J. 5(2), 7900407 (2013). CrossRef J. He, D. Yang, L. Chen, "A full-duplex radio-over-fiber system with differential phase-shift keying signals", J. Phys. Conf. 276, 012062 (2011). CrossRef L.Y. Chan, C.K. Chan, D.T.K Tong, E Tong, L.K. Chen, "Upstream traffic transmitter using injection-locked Fabry-Perot laser diode as modulator for WDM access networks", Electron. Lett. 38(I), 43 (2002). CrossRef Z. Xu, Y. J. Wen, C. J. Chae, Y. Wang, C. Lu, Proc. Opt. Fiber Commun. Conf. (OFC06), JThB72 (2006). C.H. Yeh, C.W. Chow, H.Y. Chen, J.Y. Sung, Y.L. Liu, "Demonstration of using injection-locked Fabry-Pe?rot laser diode for 10?Gbit/s 16-QAM OFDM WDM-PON", Electron. Lett. 48(15), 940 (2012). CrossRef J. H. Lee et al., "Single, Depolarized, CW Supercontinuum-Based Wavelength-Division-Multiplexed Passive Optical Network Architecture With C-Band OLT, L-Band ONU, and U-Band Monitoring", IEEE J. Light. Tech. 25(10), 2891 (2007). CrossRef Q.T. Nguyen et al., "Bidirectional Transmission in Colourless WDM-PON based on Injection-Locked Fabry-Perot Laser at 2.5 Gbit/s using Low-Cost Seeding Source", in: Proc. Eur. Conf. Opt. Commun. (ECOC), Vienna, Austria, Paper 6.5.1, (2009). DirectLink T. Yoshida, S. Kimura, H. Kimura, K. Kumozaki, T. Imai, "A new single-fiber 10-gb/s optical loopback method using phase Modulation for WDM optical access networks", J. Lightw. Technol. 24,786 (2006) CrossRef W. Hung, C.-K. Chan, L.-K. Chen, F. Tong, "An optical network unit for WDM access networks with downstream DPSK and upstream remodulated OOK data using injection-locked FP laser", IEEE Phot. Techn. Lett. 15(10), 1476 (2003). CrossRef OptiSystem Package from Optiwave.

Power Budget Analysis of Colorless Hybrid WDM/TDM-PON Scheme Using Downstream DPSK and Re-modulated Upstream OOK Data Signals

Hybrid wavelength-division multiplexed/time-division multiplexed passive optical access networks (WDM/TDM-PONs) combine the advance features of both WDM and TDM PONs to provide a cost-effective access network solution. We demonstrate and analyze the transmission performances and power budget issues of a colorless hybrid WDM/TDM-PON scheme. A 10-Gb/s downstream differential phase shift keying (DPSK) and remodulated upstream on/off keying (OOK) data signals are transmitted over 25 km standard single mode fiber. Simulation results show error free transmission having adequate power margins in both downstream and upstream transmission, which prove the applicability of the proposed scheme to future passive optical access networks. The power budget confines both the PON splitting ratio and the distance between the Optical Line Terminal (OLT) and Optical Network Unit (ONU).

TWDM-PON With Signal Remodulation and Rayleigh Noise Circumvention for NG-PON2

We propose and demonstrate a 40-Gb/s (4 × 10 Gb/s) downstream and 10-Gb/s (4 × 2.5 Gb/s) upstream time-wavelength-division-multiplexed passive optical network (TWDM-PON) using signal remodulation. Here, a downstream differential-phase-shift-keying (DPSK) signal and an upstream remodulated carrier-suppressed single-sideband non-return-to-zero (CS-SSB-NRZ) signal are used, which are wavelength shifted to circumvent Rayleigh backscattering (RB). A silicon-based optical microring resonator (MRR) filter is preinstalled at the optical networking unit (ONU) to select the desired downstream wavelength and simultaneously demodulate the downstream DPSK signal, which is then detected by a monolithic-integrated germanium-on-silicon (Ge-Si) photodiode (PD). Using silicon-based devices could be cost effective for the cost-sensitive ONU. The future monolithic integration of a silicon filter, a silicon detector, and a silicon modulator in the ONU is also discussed. The characteristics of the preinstalled silicon-based MRR and the Ge-Si PD are discussed. Error-free transmission (bit-error rate (BER) <;10-9 ) is achieved in both downstream and remodulated upstream signals after propagating through 20 km of standard single-mode fiber (SMF).

Simultaneous DPSK demodulation and chirp management using delay interferometer in symmetric 40-Gb/s capability TWDM-PON system

We propose a symmetric 40-Gb/s aggregate rate time and wavelength division multiplexed passive optical network (TWDM-PON) system with the capability of simultaneous downstream differential phase shift keying (DPSK) signal demodulation and upstream signal chirp management based on delay interferometer (DI). With the bi-pass characteristic of DI, we experimentally demonstrate the bidirectional transmission of signals at 10-Gb/s per wavelength, and achieve negligible power penalties after 50-km single mode fiber (SMF). For the uplink transmission with DI, a ~11-dB optical power budget improvement at a bit error ratio of 1e-3 is obtained and the extinction ratio (ER) of signal is also improved from 3.4 dB to 13.75 dB. Owing to this high ER, the upstream burst-mode transmitting is successfully presented in term of time-division multiplexing. Moreover, in our experiment, a ~38-dB power budget is obtained to support 256 users with 50-km SMF transmission.

Using Downstream DPSK and Upstream Wavelength-Shifted ASK for Rayleigh Backscattering Mitigation in TDM-PON to WDM-PON Migration Scheme

A migration scheme from time-division-multiplex passive optical network (TDM-PON) to wavelength-division-multiplex PON (WDM-PON) using differential phase-shift keying (DPSK) for the downstream signal and wavelength-shifted amplitude-shift keying (WS-ASK) for the upstream signal is demonstrated. The migration scheme does not change the existing fiber infrastructure. An optical filter is preinstalled at the optical networking unit (ONU) to select the desirable downstream wavelength for the WDM-PON and simultaneously demodulate the downstream DPSK signal. Signal remodulation is used to generate the upstream signal by reusing the downstream wavelength. In the ONU, by wavelength shifting the upstream optical spectrum with respect to the downstream optical spectrum, the Rayleigh backscattering (RB) interference beat noise affecting the upstream signal can be significantly mitigated. The optimum bandwidth for the downstream DPSK demodulation is analyzed. The downstream and upstream transmission performances at different split ratios are also discussed.

A Broadcast-Capable WDM Passive Optical Network Using Offset Polarization Multiplexing

We propose and demonstrate a wavelength-division-multiplexed passive optical network providing both unicast and broadcast services using an offset polarization multiplexing technique. The downstream differential phase-shift keying (DPSK)-formatted unicast and broadcast signals are offset polarization-multiplexed at the central office and demultiplexed and detected at the optical network units without resorting to any polarization tracking. A portion of the offset polarization-multiplexed downstream signals is fed into a polarization-sensitive weak-resonant-cavity Fabry-Perot laser diode for upstream remodulation without any polarization control. Successful transmissions of 10-Gb/s downstream unicast and broadcast DPSK signals as well as 2.5-Gb/s upstream ON-OFF keying signal over a 20-km standard single-mode fiber are experimentally demonstrated. The robustness of the proposed scheme against polarization fluctuation along the link, relative bit delay between the unicast and broadcast signals, frequency deviation of the downstream signals from the delay interferometer (DI), and imperfection of the DI is investigated.

Heterogeneous radio-over-fiber passive access network architecture to mitigate Rayleigh backscattering interferometric beat noise

We propose and experimentally demonstrate a hybrid radio-over-fiber (ROF) wavelength division multiplexed and time division multiplexed passive optical network (WDM-TDM PON) architecture to mitigate Rayleigh backscattering (RB) interferometric beat noises. Here, only a single wavelength is needed at the central office (CO) to generate the downstream baseband data for optical wired application and optical millimeter-wave (mm-wave) signal for wireless application. The upstream signal is produced by remodulating the downstream signal. No optical filter is required at the optical network unit/remote antenna unit (ONU/RAU) to separate the optical wired and optical mm-wave signals. In the proposed network, 10 Gb/s differential phase shift keying (DPSK) signal is used for the downstream optical wired application and 2.5 Gb/s on-off keying (OOK) signal on 20 GHz carrier is used for the optical mm-wave signal. In each ONU, a reflective optical semiconductor amplifier (RSOA) is used to remodulate and produce a 2.5 Gb/s OOK format for upstream traffic. As the back-refection produced by the downstream DPSK signal and the upstream OOK signal is traveling in different fiber path, RB noise at the CO can be completely mitigated.

40-Gb/s downstream DPSK and 40-Gb/s upstream OOK signal remodulation PON using reduced modulation index

As different high speed signal-remodulation wavelength division multiplexed--passive optical network (WDM-PON) solutions up to 10 Gb/s have been proposed, researchers are going to further increase the data rate of PON towards 40 Gb/s or higher. However, scaling up from 10 Gb/s/wavelength to 40 Gb/s/wavelength PON is very challenging. Although many studies have been performed on upgrading the exiting 10 Gb/s network to 40 Gb/s, the study of the 40 Gb/s signal-remodulation network is very little. In this work, we will first study the chromatic dispersion effect on the signal-remodulation PON. Then, we will propose and demonstrate a signal-remodulation PON using 40-Gb/s downstream differential-phase shift keying (DPSK) and 40-Gb/s upstream on-off keying (OOK) signals. By using the reduced modulation index (RMI) of the downstream DPSK signal, the tolerance to the residual chromatic dispersion of the whole system can be greatly enhanced. Due to the reduced impact of the accumulated chromatic dispersion, the quality of the upstream remodulated OOK signal can be significantly improved. Besides, by detecting the downstream demodulated DPSK signal at the destructive output port of the demodulator, good quality of the demodulated DPSK signal can still be achieved.

Mitigation of Signal Distortions Using Reference Signal Distribution With Colorless Remote Antenna Units for Radio-Over-Fiber Applications

In this paper, we propose and demonstrate a bidirectional radio-over-fiber (ROF) system using a reference signal distribution. In order to minimize the radio-frequency (RF) signal attenuation as well as limit the transmit power to moderate levels, small cell size, or picocell is used in the ROF system. This will result in the need of many base stations (BSs) to provide sufficient network coverage. Because of this, colorless remote antenna unit (RAU) with optical carrier generated and distributed from the head end (HE) is employed. Experimental results show that error-free signal transmission and remodulation using downstream differential phase shift keying (DPSK) and upstream on-off keying (OOK) is achieved in a 20-km reach ROF system. Experimental characterization of the reflective semiconductor optical amplifier (RSOA)-based remodulation unit is also performed. Numerical simulation is performed to compare the proposed scheme with several conventional optical millimeter-wave (mm-wave) schemes, including double sideband (DSB), optical carrier suppression (OCS), and single sideband (SSB). Results show that the proposed scheme could be a potential candidate to mitigate signal distortions due to signal fading and code time shifting.

An optical network unit for WDM access networks with downstream DPSK and upstream remodulated OOK data using injection-locked FP laser

We investigate the use of optical differential phase-shift keying (DPSK) as the downstream modulation format in a low-cost upstream data remodulation scheme for a wavelength-division multiplexing (WDM)-based passive optical network. A 2.5-Gb/s upstream data transmitter is realized by directly modulating a Fabry-Perot (FP) laser, injection-locked with a 10-Gb/s downstream optical DPSK signal. A simple polarization-offset technique is proposed to largely minimize the induced power penalty.