Bidirectional Passive Optical Network Research Articles

Bidirectional TFDM 200 G coherent PON with a simplified receiver at the ONU side.

Time and frequency division multiplexing (TFDM) coherent passive optical networks (PONs) are considered as a promising candidate for future optical access networks due to the advantage of high sensitivity, high spectral efficiency, and flexibility. We propose a novel, to our knowledge, bidirectional TFDM 200-Gb/s coherent PON architecture based on the digital subcarrier multiplexing (DSCM) technology. A polarization-insensitive simplified coherent receiver is achieved at the ONU side by Alamouti coding and heterodyne detection. We experimentally demonstrate this bidirectional coherent PON with a 50-Gbaud Alamouti 16 quadrature amplitude modulation (QAM) signal transmitted downstream and a 25-Gbaud dual polarization (DP)-16QAM signal transmitted upstream. By using a single sideband modulated transmitter, only one laser source is required at the optical network unit (ONU) side. The power budgets can reach 30 and 33 dB for the downstream and upstream, respectively, after the 20-km transmission over a standard single-mode fiber (SSMF).

Bidirectional Passive Optical Network Employing Different Line codings/Modulation Formats in Wavelength Reused RSOA Based Symmetrical 10 Gbps

Passive optical networks (PONs) with the integration of multiple channels are the high capacity systems to cater the large number of channels in order to fulfill demands of internet applications. To realize a crosstalk suppressed and cost effective system, an integrated multi channel PON for mitigation of the crosstalk between upstream and downstream channels using different pulse shapes such as Return to zero (RZ), non RZ (NRZ), compressed spectrum RZ (CSRZ), Differential phase shift keying (DPSK) is proposed. Use of reflective semiconductor optical amplifier (RSOA) has been proposed for upstream modulation to make system cost efficient. 2-channel downstream and 2-channel upstream wavelengths are used to exhibits total symmetrical data rate of 10 Gbps. Results revealed that proposed system can support 10 Gbps data rate up to 20 km

A novel design of energy efficient bidirectional passive optical green networks using reduced buffer with small packet size technique

AbstractEnergy saving and reduction in the emission of carbon dioxide, sulfur, etc. have become one of the prime focus for the deployment of next generation networks. Due to less power consuming, passive optical networks are the best promising solution for such networks. We have proposed different aggressive schemes to reduce the energy consumption viz. no buffer, with buffer, reduced buffer, and reduced buffer with small packet. We evaluated the performance of proposed schemes for downstream and upstream by exploring the relationship between power consumption, delay, and average traffic load. The “reduced buffer with small packet” scheme has shown a reduction of more than 35% of total leakage power at the central office with the compromise of delay in packets receiving.

Zero Guard Band Multi-Twin-SSB System in Single Fiber Bidirectional PON Transmission

We propose a novel zero guard band (ZGB) multi-twin-SSB bidirectional passive optical network system which combines the multiband carrier-less amplitude phase and twin single sideband (SSB) modulation techniques. The multi-twin-SSB signal is generated at the downlink transmitter side with zero guard band between the left-sideband and right-sideband. A weak local oscillator which is extracted from the uplink optical source aids the downstream signal detection. Kramers-Kronig algorithm is used at both downlink and uplink receiver sides to reconstruct the SSB signal and eliminate the signal-signal beat interference. The downstream and upstream signals are transmitted in a single fiber without any spectral overlap between them and the Rayleigh backscattering noise is removed by the optical band-pass filter. The proposed scheme is extensively investigated and analyzed with four sub-bands using 50 Gbps 16-QAM modulation for each sub-band over a bidirectional 50 km transmission. The results show that, compared with the conventional multi-twin-SSB scheme, the proposed ZGB multi-twin-SSB scheme can improve the spectral efficiency by about 11%. The required optical signal to noise ratio (OSNR) and the required received optical power (ROP) can be reduced by more than 15 dB and 7 dB respectively at the 7% hard decision forward error correction (HD-FEC) threshold (bit error rate of $3.8\times 10^{-3}$ ), respectively. For the uplink transmission, the required ROPs for the inner and outer sub-bands at 7% HD-FEC are about −10 dBm and −11 dBm, respectively. And the signal to noise ratio to the corresponding ROPs for the inner and outer sub-bands are 15.4 dB and 15.3 dB, respectively.

Performance Evaluation of Optical Networks Using Advanced Modulation Format

In this paper, we have evaluated the performance of DPSK advanced modulation format in a bidirectional passive optical network for a triple play scenario at a constant symmetrical data rate of 10 Gbps. Data, voice and video signal has been successfully transmitted to a maximum of 128 users for a maximum distance of 100 km. Network performance was measured in terms of the Q factor, BER and eye opening, as a function of the number of users and distance of reach.

Investigation and Evaluation of Bidirectional MDM PON Employing Concept of Mode Reuse

Background/Objectives: The main aim of this research paper is to evaluate the bidirectional mode division multiplexing passive optical network employing concept of mode reuse. Methods/Statistical Analysis: In this work mode reuse in MDM-PON has been intensifying the field of research due its enormous benefits. But not much work has been reported in this regard till now. In this paper the main focuses on bidirectional PON using MDM for odd modes. Mode reuse concept has been employed for upstream transmission by demodulating it through new data. Findings: While analyzing results it reveals that the upstream transmission at 45Gbps for 48 users has been attained and for downstream, again 48 users have been supported without any amplifier and dispersion compensation. Q-factor of 15 is observed in case of downstream and 11 in case of upstream for 48 users using bidirectional scheme BER of 10^-53 has been observed for downstream and 10^-30 for upstream. Application/Improvement: Use of the bandwidth efficient modulation schemes such as QAM, QPSK and DPQPSK can be studies in this work along with higher order modes. And work can be further extended to increase the data rate.

Demonstration of Bidirectional PON Based on Mode Division Multiplexing

Recently, mode division multiplexing (MDM) has been introduced into optical transmission systems and networks for capacity enhancement. In this letter, we propose a bidirectional passive optical network (PON) architecture based on MDM. The bidirectional optical distribution network of the MDM-PON consists of few-mode fiber, passive mode multiplexer/demultiplexer, and few-mode circulators, all of which are characterized by low modal-crosstalk. Signals in different modes are able to be transmitted and received independently for both downstream and upstream transmission. We experimentally demonstrate the bidirectional MDM-PON transmission over 10-km two-mode optical fiber. The 10-Gb/s ON–OFF-keying signals can be independently transmitted and directly detected without coherent receiver and multiple-input multiple-output processing. Moreover, nonlinear transmission impairments are experimentally investigated.

EFFECT OF CHANNEL SPACING ON THE SIGNAL QUALITY FOR A BI-DIRECTIONAL TWDM PON

As the demand for broadband services increase coupled with the introduction of new services like online interactive gaming, high definition video TV, video on demand etc., the ability to support higher data rates and efficient utilization of the deployed network is necessary. This largely depends on the capacity and quality of the access networks. Currently deployed Passive Optical Networks (PON) like GPON and EPON will not be able to meet the growing demand in the future. Although both of these PONs have evolved to their respective 10G versions called XG-PON and 10G-EPON, they will eventually reach the limit of their capacity. This has paved the way for the next evolution of PON named as Next Generation PON Stage-2 (NG-PON2). NG-PON2 has the advantage of a much larger bandwidth and scalability by using a combination of Time and Wavelength Division Multiplexing known as TWDM PON. In this paper we have investigated the effect of varying channel spacing (50GHz, 100GHz and 200GHz) on the quality of a Bi-directional TWDM PON signal. The best results were obtained with the widest channel spacing of 200GHz (1.6nm).

Noise reduction in bidirectional passive optical networks with 10 Gb/s differential phase shift keying downstream and 2.5 Gb/s coded return-to-zero upstream signal

A novel scheme is demonstrated for reducing the noise of residual modulation and rayleigh backscattering in wavelength reused bidirectional wavelength-division-multiplexed passive optical networks with differential phase shift keying (DPSK) downstream and 8b10b coded return-to-zero (CoRZ) remodulated upstream. Reflective semiconductor optical amplifier based access network is designed and analyzed for 10 Gb/s DPSK downstream and 2.5 Gb/s CoRZ upstream over 25 km single feeder fiber. Error free operation is achieved with effective suppression of re-modulation noise and improved tolerance of rayleigh backscattering crosstalk down to 14 dB of signal to noise ratio.

A 20 km/80 Gbps bidirectional PON employing three-stage injection-locked VCSELs/NDFs/OBPFs

A 20 km/80 Gbps bidirectional passive optical network (PON) employing three-stage, injection-locked, 1.55 μm, vertical-cavity surface-emitting lasers (VCSELs), negative dispersion fibers (NDFs), and optical band-pass filters (OBPFs) is proposed and demonstrated. The three-stage injection-locked technique, which can greatly increase the frequency response of VCSELs, is thereby expected to provide excellent transmission performance in a bi-directional PON. To be the first one of employing directly modulated, three-stage injection-locked, 1.55 μm, VCSELs; NDFs; and OBPFs results in excellent bit error rate (BER) performance, and clear eye diagrams are obtained for 20 km/80 Gbps, bidirectional PON applications. Such a novel bidirectional PON provides the advantage of a communication link for high data rates that could accelerate bidirectional PON deployment.

Performance analysis of bidirectional hybrid orthogonal frequency division multiplexing-Ethernet passive optical access network

For the bottleneck problem of broadband access networks, the Ethernet passive optical network comes out as a striking and promising solution. Even though, Ethernet passive optical network nodes necessitate a cost-effective up-gradation. Accordingly, we propose and demonstrate a hybrid orthogonal frequency division multiplexing-Ethernet passive optical network employing an optical single side band modulation scheme. Case A demonstrates a contrast between a symmetric bidirectional single channel orthogonal frequency division multiplexing-Ethernet passive optical network at a data rate of 10 and 5 Gbps after a fiber link of 20 km. Case B targets the transmission of a symmetric bidirectional single channel orthogonal frequency division multiplexing-optical single side band-Ethernet passive optical network system and achieves a fiber link of 20 km with a split ratio of 8. Afterwards, eight upstream channels are transmitted simultaneously and successfully obtained at the optical linear terminal side to make a bidirectional Ethernet passive optical network system. Further, a contrast between transmission at a data rate of 10 and 5 Gbps is carried out that achieves a fiber link of 20 km with a split ratio of 8.

English

English

In-band simultaneous transmission of baseband and broadcast signals in wavelength reused bidirectional passive optical network

Reflective semiconductor optical amplifier (RSOA) based bidirectional wavelength division multiplexing passive optical network (WDM-PON) is proposed and analyzed for broadcasting services along with conventional baseband signal. The downstream baseband signal is spectrally shaped for in-band transmission of broadcast signal, which ensures effective utilization of transmission bandwidth. The modulated downstream optical signal is further reused for upstream data modulation and transmitted over the same fiber with suppressed re-modulation and rayleigh backscattering noises. The proposed WDM-PON is successfully demonstrated for 10Gb/s downstream baseband signal, 100Mb/s 16-QAM (quadrature amplitude modulation) in-band broadcast signal and wavelength reused 1.25Gb/s upstream signal. Error free operation for both the baseband signals as well as low value of error vector magnitude (EVM) for broadcast data are simultaneously achieved in acceptable receiver sensitivity.

Impacts of backscattering noises on upstream signals in full-duplex bidirectional PONs.

The backscattering noises introduced by Rayleigh and stimulated Brillouin scattering have been experimentally studied by means of their spectrum broadening, the scattering power variation and their impacts on upstream signals with different transmission fiber lengths and incident powers in a single-fiber bidirectional passive optical network (PON) communication system. The results show that both spontaneous scattering and simulated scattering can take place. The power and spectrum of backscattering noises are determined by the downstream launch power, laser linewidth and transmission fiber length. With the transmission length increasing, the power of backscattering noises gets higher, the spectrum of the backscattering noise broadens and the simulated threshold power decreases. The backscattering noise can beat with uplink light to modulate envelop of upstream signal resulting in degradation of BER greatly. Under the condition of one single channel for the second next generation PON (NG-PON2), the fiber length is 40km and downstream launch power is up to 11dBm. At this time, the backscattering noises are easy to be stimulated and the scattering power rises up from -20dBm to 10dBm, which can overwhelm the US signal. The spectrum of the optical beat interference noise also rises up with fiber length, which causes the uplink's BER degradation. The experimental results are significant for mitigation of backscattering noises under the condition of bidirectional PONs.

Bidirectional Wavelength Reconfigurable Module Based on Tunable Fiber Bragg Grating and Remote Pump Amplifier

This article presents a novel bidirectional wavelength reconfigurable optical network utilizing a remotely pumped erbium-doped fiber amplifier and tunable fiber Bragg gratings. The system is experimentally demonstrated at a 10-Gb/s per channel over 20-km fiber span that verifies the metro-network range system performance. The achieved power penalty is less than 1 dB when compared to the back-to-back transmission link. An example of practical application where the proposed module is used as an add/drop multiplexer and a remote node in the bidirectional wavelength division multiplexing passive optical network system is described.

Performance evaluation of bi-directional passive optical networks in the scenario of triple play service

In this paper, the performance of bi-directional passive optical network (BPON) has been evaluated and compared at different bit rates in the scenario of triple play service. The triple-play service is realized as a combination of data, voice and video signals. This architecture is investigated for symmetrical data traffic for uplink and downlink transmission and its performance is also evaluated in terms of Q-factor and eye height at different transmission distance. The Q-factor results show the acceptable performance at 10Gbps data rate for downstream and upstream transmission, as it accommodates 128 optical network units (ONUs). Further the proposed system's performance is compared with the current state-of-the-art PON architectures.

Investigation on wavelength re-modulated bi-directional passive optical network for different modulation formats

In this paper, the cost effective bi-directional passive optical network architecture with wavelength remodulated scheme is investigated. To realize the cost-effective PON, remodulation scheme is used, in which the downstream optical signal is reused as a carrier for the upstream transmission as it eliminates the need for an extra laser source at optical network units. The performance of proposed passive optical network is analyzed and compared for various modulation formats such as Non Return to Zero (NRZ), Return to Zero (RZ) and On–Off Keying (OOK) with 64 optical networks units (ONUs) at different traffic speed for downlink and uplink, respectively. It has been observed that the most suitable data format for proposed PON network is NRZ. Further the proposed system performance is compared with the current state-of-the-art PON architectures.

An experimental demonstration for carrier reused bidirectional PON system with adaptive modulation DDO-OFDM downstream and QPSK upstream signals

A light source centralized bidirectional passive optical network (PON) system based on multiband direct-detection optical orthogonal frequency division multiplexing (DDO-OFDM) downstream and quadrature phase-shift keying (QPSK) upstream is experimentally demonstrated. By introducing a simple optical single-side band (SSB) filter at the optical network unit (ONU), all the desired signal bands will be immune from the deleterious signal-signal beating interference (SSBI) noise with only single-end direct-detection scheme. An adaptive modulation configuration is employed to enhance the entire downstream throughput which results in a 150-Gbps downstream data rate with a single optical carrier. In the upstream direction, by recycling the clean downstream optical carrier, a 12.5 Gb/s QPSK format with coherent receiving mechanism in central office is adopted for better receiving sensitivity and dispersion tolerance. With the power enhancement by the long-reach PON architecture, the downstream splitting ratio can achieve as high as 1:1024.

Study of the Bidirectional PON Performance Based on the Optisystem

This paper presents the background of PON (Passive Optical Network), introduces the powerful communication design and simulating software which named Optisystem, show the PON(Passive Optical Network) theory and structure, designs the PON fiber link which has 1310nm uplink wavelength and 1490nm downlink wavelength and then analyses the models performance. In the software, we set up a rate of 1Gbps model of PON by using the component in the Optisystem. Through calculating the model, the document gets the spectrum figure of the simulate fiber link, and analyses the parameter, such as spectrum character, Q factor, eye diagram and BER, the result verified the validity and practicable of the models design, makes the result that the initial character fiber link cant meet the demand of optical communication, so changing the transmission distance to 10 km , transmitter power to-1dBm, meeting and obtaining the basic requirements of the system performance, after that the paper comparing the coding between none return to zero (NRZ) and return to zero (RZ) encoded mode, the eye diagram analyzer component show that NRZ code is better than RZ code, in the end of the paper there is the conclusion.

A bidirectional lightwave transport system based on PON integration with WDM VLC

A novel bidirectional lightwave transport system employing phase modulation (PM) scheme and light injection-locked distributed feedback laser diode (DFB LD) as a duplex transceiver for passive optical network (PON); as well as employing laser pointer lasers (LPLs) with directly modulating data signals for wavelength-division-multiplexing (WDM) visible light communication (VLC) is proposed and experimentally demonstrated. Impressive and low bit error rate (BER) operation is achieved for PON integration with VLC application. Such bidirectional PON integration with VLC system has been successfully demonstrated, which can not only present its advancement in PON/VLC application but also reveal its simplicity and convenience to be installed. Whereby, our proposed system is suitably applicable to the PON in combination with VLC system in wire and wireless transmission.