Colorless Wavelength Division Multiplexed Passive Optical Network Research Articles

Enhanced noise tolerance for 10 Gb/s Bi-directional cross-wavelength reuse colorless WDM-PON by using spectrally shaped OFDM signals

Abstract Spectrally shaped orthogonal frequency division multiplexing (OFDM) signal for symmetric 10 Gb/s cross-wavelength reuse reflective semiconductor optical amplifier (RSOA) based colorless wavelength division multiplexed passive optical network (WDM-PON) is proposed and further analyzed to support broadband services of next generation high speed optical access networks. The generated OFDM signal has subcarriers in separate frequency ranges for downstream and upstream, such that the re-modulation noise can be effectively minimized in upstream data receiver. Moreover, the cross wavelength reuse approach improves the tolerance against Rayleigh backscattering noise due to the propagation of different wavelengths in the same feeder fiber. The proposed WDM-PON is successfully demonstrated for 25 km fiber with 16-QAM (quadrature amplitude modulation) OFDM signal having bandwidth of 2.5 GHz for 10 Gb/s operation and subcarrier frequencies in 3–5.5 GHz and DC-2.5 GHz for downstream (DS) and upstream (US) transmission respectively. The result shows that the proposed scheme maintains a good bit error rate (BER) performance below the forward error correction (FEC) limit of 3.8 × 10−3 at acceptable receiver sensitivity and provides a high resilience against re-modulation and Rayleigh backscattering noises as well as chromatic dispersion.

Colorless WDM-PON using single side band carrier suppressed signals mitigating carrier rayleigh backscattering

A new scheme is offered for minimizing carrier Rayleigh backscattering (CRB) in single feeder fiber based wavelength division multiplexed passive optical network (WDM-PON). The proposed scheme is based on single side band carrier suppressed (SSB-CS)signal, both at network and receiver sides, used for the first time at optical line terminal (OLT) and optical network unit (ONU)sides. We use dual-drive Mach-zehnder modulator (DD-MZM)for generating SSB-CS signals, which decreased the expense per bit in full transmission. SSB-S mitigated CRB, both at OLT and ONU sides, because of having no chance of reflections from the carrier. Since no extra dedicated RF or laser source is used at ONU side, we thus achieve cost effective colorless WDM-PON system. Suppressed signals from four channels, each of 10 Gbps, are multiplexed before injecting into the fiber span of 25 km at OLT. At ONU side, half of the down-link power is used for re-modulating the data signal. The simulation results show an error free transmission. Moreover, the detailed power budget calculations show that the proposed scheme can be sought out for splitting ratio up to 128. Hence it offers enough system's margin for unseen losses.

Performance analysis of symmetrical 10 Gbps colorless WDM-PON using subcarrier modulated downstream and wavelength converted upstream through RSOA

Here we have demonstrated a novel architecture of colorless wavelength division multiplexed-passive optical network (WDM-PON) and analyze its performance which is capable of transmitting 10Gbps data symmetrically in both downstream and upstream. In this architecture downstream data is subcarrier modulated (SCM) using radio frequency (RF) as subcarrier and laser frequency as carrier with the help of a Mach–Zehnder modulator (MZM). For upstream data modulation an electro-absorption modulator, an optical coupler and reflective semiconductor optical amplifier (RSOA) are used. Upstream data is transmitted through wavelength conversion between pump wavelength and continuous wave light sent from central office (CO) using cross gain modulation (XGM) in RSOA. Pump wavelengths have separate wavelength band than the carrier's wavelength sent from optical network unit (ONU) and can be chosen any one in its band. Since carrier reuse scheme is implemented so all the ONUs are operates in colorless mode. Effect of ER of delay interferometer (DI) on output OCSR of DI for different input OCSR is performed for SCM data. Simulation is performed with all 16 downlink and 16 uplink channels having data rate of 10Gbps having acceptable performance.

Single-feeder fiber colorless wavelength-division-multiplexing passive optical network using differential quadrature phase-shift keying downstream and intensity remodulated upstream signals

Wavelength-division-multiplexing passive optical network (WDM-PON) has been considered as a promising next generation access network solution. A centralized light-wave colorless WDM-PON architec- ture based on a single feeder fiber. At the optical line terminal, differential quadrature phase shift keying (DQPSK) modulated signal at 10 Gbps is utilized for downstream transmission is proposed and demonstrated. At the optical line unit, part of the downstream signal is remodulated using an intensity modulated on/off keying technique for upstream transmission. Simulation results show that downstream and upstream signals achieved error-free transmission at 10-Gbps symmetric data rate with negligible power penalties. The proposed scheme exhibit improved tolerance to Rayleigh backscattering over 20 km standard single mode fiber. © 2013

Single fiber colorless symmetric WDM-PON architecture using time interleaved remodulation technique for mitigating Rayleigh backscattering resilience

A time interleaved differential phase shift keying (DPSK) remodulation technique is proposed to mitigate the effect of Rayleigh backscattering (RBS)-induced noise in a single fiber colorless wavelength-division-multiplexing passive optical network (WDM-PON). In order to achieve a cost effective optical network unit (ONU) solution without dedicated laser sources for upstream signals to provide optimum symmetric capacity in a colorless WDM-PON, remodulation becomes the core attraction. Also as the performance of colorless WDM-PON systems suffers from the transmission impairments due to RBS, it is mitigated by using this remodulation scheme. Simulation results show that downstream and upstream signals achieve the error-free performance at 10 Gbit/s with negligible penalty, and enhance the tolerance to RBS-induced noise over a 25 km single-mode fiber.

Rayleigh backscattering minimization in single fiber colorless WDM-PON using intensity remodulation technique

The performance of colorless wavelength-division multiplexed passive optical network (WDM-PON) systems suffers from the transmission impairments mainly due to Rayleigh backscattering (RB). In this paper, we propose and demonstrate a single fiber colorless WDM-PON which enhances the tolerance to RB induced noise. The high extinction ratio in both return-to-zero (RZ)-shaped differential phase shift keying (DPSK) downstream (DS) data signal and intensity-remodulated upstream (US) data signal helps to improve the tolerance to RB induced noise. Simulation results show that downstream and upstream signals can achieve error-free performance at 10 Gbit/s with negligible penalty and improve the tolerance to RB induced noise over 25 km standard single-mode fiber.

An AWG-based 10 Gbit/s colorless WDM-PON system using a chirp-managed directly modulated laser

We propose an arrayed waveguide grating (AWG)-based 10 Gbit/s per channel full duplex wavelength division multiplexing passive optical network (WDM-PON). A chirp managed directly modulated laser with return-to-zero (RZ) differential phase shift keying (DPSK) modulation technique is utilized for downlink (DL) direction, and then the downlink signal is re-modulated for the uplink (UL) direction using intensity modulation technique with the data rate of 10 Gbit/s per channel. A successful WDM-PON transmission operation with the data rate of 10 Gbit/s per channel over a distance of 25 km without any optical amplification or dispersion compensation is demonstrated with low power penalty.

An AWG based colorless WDM-PON with RZ-DPSK modulated downstream and re-modulation of DL signal for OOK upstream

We proposed an arrayed waveguide granting (AWG) based 10 Gbps full duplex wavelength division multiplexing passive optical network (WDM-PON) utilizing a return-to-zero differential phase shift keying (RZDPSK) modulation technique for down-link direction and then re-modulation of the downlink (DL) signal for the uplink (UL) direction using intensity modulation technique (OOK) with a data rate of 10 Gbps per channel. A successful cost effective colorless WDM-PON full duplex transmission operation for a data rate of 10 Gbps per channel, with a channel spacing of 60 GHz over a distance of 25 km without any optical amplification and dispersion compensation is achieved within low power penalty.

Simple Colorless WDM-PON With Rayleigh Backscattering Noise Circumvention Employing $m$-QAM OFDM Downstream and Remodulated OOK Upstream Signals

We propose and experimentally demonstrate a new colorless wavelength-division-multiplexed passive optical network (WDM-PON) architecture with the Rayleigh backscattering (RB) interferometric beat noise mitigation by using cross-remodulation architecture. The proposed WDM-PON has a simply configuration by combining two WDM-PONs at two wavelength bands to support twice the number of users. We experiment different m-quadrature amplitude modulation (QAM) (m = 16, 32 and 64) orthogonal frequency division multiplexing (OFDM) downstream signal and the remodulated on-off keying (OOK) upstream signal by using the 2.5 GHz directly modulated laser (DML) and 1.2 GHz reflective semiconductor optical amplifier (RSOA) respectively. Hence, the total data rate achieved for the downstream signals are 10 Gb/s, 12.5 Gb/s, and 15 Gb/s respectively for different m -QAM. For the upstream signal, we over-drive the RSOA and 2.5 Gb/s OOK upstream traffic can be achieved. In addition, the proposed PON can also be upgraded to support more wavelength bands to meet the increase demand of capacity.

A novel duplex WDM-PON with DPSK modulated downstream and re-modulation of the downlink signal for OOK upstream

We experimentally demonstrate and analyze a 10 Gbit/s full duplex wavelength division multiplexing passive optical network (WDM-PON) system. A non-return-to-zero differential phase shift keying (NRZ-DPSK) modulation technique is first utilized for downlink direction, and then the downlink signal is re-modulated for the uplink direction using intensity modulation technique of on-off keying (OOK) with a data rate of 10 Gbit/s per channel. An effective colorless WDM-PON full duplex transmission system is achieved for the data rate of 10 Gbit/s per channel with a channel spacing of 60 GHz over the distance of 25 km with low power penalty.

Colorless gigabit WDM-PON link using injection locking and electro-absorption transceiver

In this paper, a novel colorless wavelength division multiplexing-passive optical network (WDM-PON) system using injection locking and electro-absorption transceiver (EAT) is proposed and demonstrated experimentally. This system has advantages, high data transmission, small downlink signal effect to uplink signal and less polarization sensitivity, compared to the system using reflective semiconductor optical amplifier (RSOA). Downlink signal modulates the right side carrier of the double side band signal by using injection locking. EAT functions as both photo detector in downlink signal and modulator for uplink signal, simultaneously. A possible cross absorption modulation effect from the EAT is analyzed experimentally. Bidirectional transmission of 1.25 Gbps and 622 Mbps for downlink and uplink, respectively, were verified through 23 km standard single mode fiber (SSMF).

Improvement of modulation bandwidth in multisection RSOA for colorless WDM-PON

We demonstrated two-section reflective semiconductor optical amplifier (RSOA) with dramatic improvement of small-signal modulation bandwidth above 10 GHz as colorless source for wavelength division multiplexed-passive optical network (WDM-PON). The device provides the fiber-to-fiber gain of 22.8 dB, 3-dB amplified spontaneous emission (ASE) bandwidth of 30 nm, and ripple of 1.5 dB. Good performance at 2.5 Gbps was obtained with an extinction ratio of 8 dB and a power penalty of 2 dB at a 10(-9) bit error rate (BER) up to 20 km transmission.

A self-protected colorless WDM-PON with 2.5 Gb/s upstream signal based on RSOA

In this investigation, we propose and demonstrate a colorless wavelength division multiplexed passive optical network (WDM-PON) at 2.5 Gb/s using reflective semiconductor optical amplifier (RSOA)-based optical networking units (ONUs); together with a self-protected architecture against fiber fault. In the optical line terminal (OLT), we use an array of self-seeding Fabry-Perot laser diodes (FP-LDs) to provide single-longitudinal-mode (SLM) continuous wave (CW) optical sources for the external injection to the RSOA-based ONUs. The self-survivable function for protecting the fiber fault in the distributed fibers and the proposed network performance are investigated and discussed.