Comparison of chromatic dispersion compensation techniques for WDM-PON solution

The present paper proposes the optimal transmission parameters for non-return-to-zero (NRZ), return-to-zero differential phase shift keying (RZ-DPSK), carrier-suppressed RZ-DPSK (CSRZ-DPSK) and duobinary (DB) modulation formats in 16-channel 10 Gbit/s wavelength division multiplexed passive optical network (WDM-PON) transmission system. The paper investigates influence of laser output power, length of dispersion compensating fiber (DCF) and application of erbium-doped fiber amplifiers (EDFA), as well as impact of optical components configuration on received signal quality. It compares demand of these modulation formats for amplification and dispersion compensation with the increase of transmission distance, determining the optimal conditions for achieving maximal network reach for each of them. It is shown, that DB is the most resistant to chromatic dispersion (CD) and is able to achieve the longest transmission distance (100 km) without dispersion compensation. Whereas RZ-DPSK and CSRZ-DPSK modulation formats demonstrated maximal achievable reach (180 km) using DCF and EDFA.

This paper successfully demonstrates bidirectional wavelength division multiplexing passive optical network (WDM-PON) system for 32 channels, 0.8 nm (100 GHz) channels spacing with 3.5 GHz filter bandwidth. The system delivers 160 GB/s data rate and 80 GB/s data rate in downstream and upstream, respectively. The optical source for downstream data and upstream data is mode-locked laser at central office and reflective semiconductor optical amplifier (RSOA) at optical network unit. The maximum reach of designed system is 50 km without using any dispersion compensation scheme. This paper comprises comparison of series of modulation format in downstream and upstream such as SOLITON, NRZ, RZ, MANCHESTER, CSRZ and CRZ-DPSK and optimization of the performance of designed system. It has been observed that CRZ-DPSK/NRZ gives best performance in downstream and upstream transmission for designed system. The simulation work report of minimum BER is e

Fault detection technique for wavelength division multiplexing passive optical network using chaotic fiber laser

In this paper we evaluate what parameters of the elements of transmission system have high impact on the performance of wavelength-division-multiplexed passive optical network (WDM-PON). The increasing of data rate is one of the solutions for satisfying growing demands on the capacity of transmission system. However, the higher data rate is, the higher the technological issues and expenses on its realization are. That is why the choice of the elements of transmission system with high data rate becomes crucial. For this reason, it is important to investigate what parameters of the elements of transmission system have higher impact on transmission quality. The paper focuses on the eight-channel 40Gbit/s transmission system. WDM-PON systems with Duobinary (DB) and pulse-amplitude-modulation (PAM-4) modulation formats are considered. The paper evaluates how the change of parameters of laser, modulator, fibre and photodiode influences the performance of our investigated WDM-PON. The parameters under research are following — output power, linewidth, relative intensity noise (RIN) and side-mode suppression ratio of laser, extinction ratio, bandwidth and S 21 characteristic of modulator, attenuation, dispersion and nonlinear coefficient of the fibre as well as responsivity, dark current, thermal noise and shot noise of the receiver. As a result, we investigate what parameters of each element of the transmission system are the most significant and should be considered as a primary factor in the design of WDM-PON transmission system. Based on the obtained results we propose possible solutions for the optimal realization of the eight-channel 40Gbit/s WDM-PON transmission systems with PAM4 and DB modulation formats.

We propose and demonstrate a new in-service fault-localization method for a wavelength division multiplexing passive optical network (WDM-PON). This scheme uses a tunable OTDR realized by a wavelength-locked Fabry-Perot laser diode. We successfully detect the faults both at the feeder fiber and the drop fibers. The resolution and the dynamic range are 100 m and 12 dB, respectively. In addition, the crosstalk induced by the OTDR signal to the transmission data is negligible.

With the increasing demand for bandwidth, there is an ever growing interest in fibre to the home (FTTH) technologies and its deployments. Wavelength division multiplexing passive optical networks (WDM-PONs) have received a lot of attention as one of the best contenders for next generation optical access networks. In this paper we will overview on WDM-PON architectures, focussing our attention on reflective PON schemes that offer a cost-effective, colourless solution. The critical component required for these schemes is the reflective semiconductor optical amplifier (RSOA) transmitter at the customer premises. This paper will report latest results on RSOA technology for WDM-PON.

Improved self-seeding and carrier remodulation performance for WDM-PON by means of double RSOA erasure

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.

Third generation fiber-to-the-x (FTTx) will introduce wavelength division multiplexing (WDM) technology to increase data rates up to 40 Gbit/s, as well as coexist with current communication systems. WDM passive optical network (WDM-PON) based fiber-to-the-home (FTTH) system architecture together with the Next-generation passive optical network (NG-PON) can provide solution related to nowadays problems with transmission capacity. It is expected that NG-PON systems will become more cost-efficient at high per user data rates, providing different transmission speeds for end users, based on pay-as-you-grow approach. In this paper, our introduced system model is used to obtain WDM-PON system effectiveness for different data rates of up to 32 Gbit/s per downstream transmission channel. We created combined simulative-experimental WDM-PON transmission system model in environment of RSoft OptSim simulation software to compare the performance of non-return-to-zero (NRZ) on-off-keying (OOK) modulated PON transmission system versus transmission bitrate and distance. Results showed that proposed transmission system is capable to provide data transmission of up to 32 Gbit/s per channel with BER $ , if additional forward error correction (FEC) is used. Additionally, to increase the reach of investigated system, fiber Bragg grating-based dispersion compensation module (FBG-DCM) is implemented, therefore enabling full pre-compensation of chromatic dispersion.

WDM PONs based on colorless technology

We propose a converged radio over fiber and wavelength division multiplexing passive optical networks (WDM-PON) system compatible with wired and 60 GHz band wireless transmission by implementing two-band modulation with a single Mach-Zehnder modulator (MZM) behaving as parallel phase modulators. In this paper, the interference between RF and baseband modulations is theoretically and experimentally investigated. The RF modulation impacts to the baseband signal for different RF modulation formats are deeply investigated.

We propose a booting process related to a wavelength initialization of light source of optical line terminal (OLT) and optical network terminal (ONT) in wavelength division multiplexing passive optical network (WDM-PON). A stable operation of wavelength initialization is observed for OLT and ONT optical transceiver. The proposed process use minimized optical devices such as filter and photo diode (PD) for wavelength initialization.

This paper focused on the novel design of receiver side of wavelength division multiplexing passive optical network (WDM-PON). It serves the need for a dramatic change in demand for high data rate beyond 10 gigabits per second (Gbps) at the last mile for a larger coverage area or distance. This increase in demand for higher bandwidth is due to the emerging future technologies like Internet of things (IoT), silicon on chip (SoC), cloud computing, machine learning (ML), and artificial intelligence (AI). Simulation results demonstrated for the different coverage areas which compare the bit error rate (BER), quality (Q)-Factor, and eye height as per the guidelines of ITU-T. It has been predicted that the proposed WDM-PON design supports up to a distance of 60 km. Results have been verified for 40 km, 50 km, 60 km, and 70 km, respectively, at 100 GHz frequency spacing with acceptable BER and better quality (Q)-factor as defined by ITU.

Wavelength division multiplexing passive optical network (WDM-PON) with centralized lightwave in optical line terminal (OLT) is recognized as the cost effective way in engineering application, for each optical network unit (ONU) do not have to do the laser light source configuration. In the transmission link between OLT and each ONU of the centralized lightwave WDM-PON, bilateral signal including downstream and upstream should be transmitted properly. In most reports from literature, different formats of signal modulation, including differentiated phase shift keying (DPSK), frequency shift keying (FSK), and on-off keying (OOK), are usually chosen in downlink and uplink to realize 2 or more types of service data transmission separately in a single wavelength channel. Consider that OOK format has the simplest way in system design, in this paper, a centralized lightwave WDM-PON approach has been proposed which employs OOK in both modulation and re-modulation process with only differences in extinction ratio. By simulation, the feasibility of such approach has been proved and the optimal extinction ratio for both downlink and uplink has been given.

This paper investigates bidirectional transmission using four wave mixing (FWM) for wavelength division multiplex passive optical network (WDM-PON) applications. A semiconductor optical amplifier (SOA) is considered to generate FWM. A use of FWM makes it possible to convert a downstream data wavelength to a different wavelength, which is used for upstream transmission. The wavelength generated by FWM can realize bidirectional transmission with a single fiber. We assume intensity modulation (IM) for both up- and down-transmission. Both an injection locked Fabry-Perot laser diode (FP-LD) transmitter and a transmitter with an external modulator are considered for upstream transmission. In both cases, an extinction ratio (Ex) of downstream signal light is very important for both sending and receiving properties and the Ex influences the bit error rate (BER) property. This paper clarifies the relationship between the Ex of FWM and the power penalty ΔP. This paper also clarify the Ex value of FWM as a function of input signal Ex using a model SOA theoretically. Fundamental transmission experiments, 10 Gbit/s downstream and 2.5 Gbit/ s upstream, using both types of transmitters confirmed the possibilities of the bidirectional transmission using FWM.