Next-generation Passive Optical Network Research Articles

An optimization investigation of enhanced practicality for the OFH/PC scheme based PON monitoring system

We propose a discrete and average approach, focusing on the code set rather than individual codes, for the PON monitoring system based on the optical frequency hopping/periodic code scheme. The discrete and averaged codes are designed to support large-capacity network monitoring, particular for next-generation PONs, while preserving the original encoder structure of the PON monitoring system. The proposed approach discretizes and averages optical frequency hopping/periodic codes with small and large intervals, employing a modified greedy algorithm that mitigates falling into local optimality and an efficient backtracking algorithm, respectively. Our proposed algorithms demonstrate exceptional efficiency and performance, as exemplified by the modified greedy algorithm, which surpasses the exhaustive method by over 2 millionfold in terms of speed. This approach significantly reduces the more rigorously defined probability of multiple-customer interference and lowers the final recognition difficulty, enhancing the practicality of the PON monitoring system. Additionally, we develop a cost-effective model to analyze optimal system costs for discrete-averaged codes in the cost-sensitive PON market, facilitating the practical application of the PON monitoring system in engineering practice.

تأثير ثلاث خطط مختلفة على المرحلة الثانية من الشبكات الضوئية في الجيل القادم

Abstract: In this work, a simulative analysis of 40 Gb/s downstream time and wavelength division multiplexing-passive optical network (TWDM-PON) for next-generation passive optical network second stage (NG-PON2) had been designed and demonstrated. The performance of three different wavelength plans in TWDM-PON are evaluated as the solution to NG-PON2 to support 40Gbit/s bandwidth requirement. A four 10-Gb/s TWDM-PON signals are stacked using four different wavelengths in the downstream direction and externally modulated. The system performance is observed using Bit Error Rate (BER) and Optical Signal-to-Noise Ratio (OSNR) with respect to the design parameters such as distance, number of users and received optical power. Thus, the proposed system was able to support 512 number of users and 80 km transmission distance. When the system is tested upon transmission of triple play services over 80km distance with 512 users, it is shown that BER of 8.9 × 10-10, 3.9 × 10-9 and 1.3 × 10-4 are achieved for data, voice and video, respectively.

High spectral efficiency modulation scheme based on joint interaction of orthogonal compressed chirp division multiplexing and power superimposed code.

In this paper, we propose a high spectral efficiency modulation scheme based on joint interaction of orthogonal compressed chirp division multiplexing (OCCDM) and power superimposed code (PSC) under the intensity modulation and direct detection (IM/DD) system. OCCDM is a novel orthogonal chirp division multiplexing technology featuring spectral compression through the implementation of processing similar to a discrete Fourier transform, enhancing the spectral efficiency (SE) through bandwidth savings without loss of orthogonality of each chirp. Meanwhile, PSC technology enables multiple code words being transmitted superimposed on the same chirp. This technique involves allocating varying power levels to different users, thereby distinguishing them, increasing the transmission's net bit rate and substantially boosting the SE. The transmission has been performed experimentally using a 2 km 7-core fiber span. The impact of the above-mentioned technologies on the bit error rate (BER) performance is assessed in the power, frequency, and joint domain. The BER and enhancements in the SE can be balanced when the spectral bandwidth compression factor (α) and power distribution ratio are equal to 0.9 and 4, respectively. The observed outcome leads to the transmission's SE increase to more than double the baseline value, at 2.22 times. Based on the above analysis, we believe this structure is expected to become a potential for developing next-generation PON.

Key Technologies for a Beyond-100G Next-Generation Passive Optical Network

The explosive development of emerging telecommunication services has stimulated a huge growth in bandwidth demand as people seek universal access to telecommunication networks. In addition, the kinds of services of an existing optical access network are becoming more flexible. In order to provide higher capacity and meet higher transmission performance requirements, it is necessary to further explore the application of the beyond-100G passive optical network (PON). This paper offers a comprehensive review and outline of the prospects of technologies for bringing a beyond-100G PON to practical applications in the future. We review the current existing technologies, mainly in terms of the physical layer and higher media access control layer. These key technologies for the beyond-100G PON, which plays an increasingly significant role, include the advanced multiplexing technology, physical layer digital signal processing technology, infrastructure-sharing technology, security protection technology, and intelligent control management key technologies. Finally, open issues and new challenges for the next-generation PON are focused upon.

Investigation of 2.24Tbps full-duplex integrated multi-beam FSO/MDM-next generation PON under diverse atmospheric conditions

A full-duplex 2.24Tbps mode division multiplexing (MDM) based integrated multi-beam free space optics (FSO) and next generation passive optical network (NGPON) system to mitigate the atmospheric turbulence and fiber dispersion with enhanced network scalability as well as efficiency is proposed. In emergency scenarios the utilization of polarization shift keying (PolSK) and dual polarization (DP)-differential quadrature phase-shift keying (DQPSK) modulation in system offers high spectral efficiency, coherent detection, minimum link dispersion and less noise. The simulation results demonstrate the faithful MDM-FSO/NGPON signals transmission over 40 km fiber with 500 m multi-beam FSO links at −8 dBm received power and 2 dB maximum power penalty. Also, the maximum fiber & FSO range can be expanded upto 160 km and 1500 m respectively, considering fiber impairments and diverse weather conditions. The system also supports simultaneous 200 end users having 23–47 dB total channel loss. High optical to signal noise ratio of 36 dB in downlink and 44 dB in uplink is acquired successfully. The comparison of the designed system with other systems signifies its superiority to others.

Integrated long reach and energy-efficient NGPON-VLC system with OCDM/WDM for smart green buildings

Smart green buildings (SGBs) are composed of numerous services and offer hopeful solutions to the world's continuous and rapid urbanization. Conventional data transmission systems are insufficient to deliver acceptable services because to the sudden surge in high-quality information transmission requirements over long distance for numerous linked residents in SGBs. Consequently, a hybrid next generation passive optical network (NGPON) along with visible light communication (VLC) indoor/outdoor broadcast network is presented in this work to increase the reliability with intelligence, exalted overall efficiency, cost efficiency, and security of SGBs. Bidirectional PON-VLC system incorporates the time and wavelength division multiplexing (TWDM), wavelength division multiplexing (WDM) and optical code division multiplexing (OCDM) techniques. In order to improve system performance, various OCDM codes are used in this work at 10/2.5 Gbps per channel throughput via fiber-VLC channels. According to the simulation results, the modified new zero cross-correlation (MNZCC) code performs better than previous codes and supports 200 active residents at reliable 100 km fiber along with 5 m VLC range. Furthermore, by expanding the received aperture diameter to 25 cm, VLC coverage may be increased till 10 m. Moreover, it provides adequate receiver sensitivities of − 13 to − 12 dB in uplink with − 9.8 to − 6 dBm in downlink for 200 to 600 fields of view angles compared to 00 view angle having sensitivity of − 15 dBm. Additionally, the numerical analysis and comparison performance show that PON-VLC outperforms fiber-VLC link-based scenarios when it comes to noise and channel impairments.

A Novel 64 QAM-OFDM Optical Access System Based on Bit Reconstruction

This paper proposes a novel orthogonal frequency division multiplexing (OFDM) optical access scheme based on bit reconstruction. In this method, correlation is introduced into the data information of optical line terminals (OLT) through the logical coding circuits and partition mapping. Even after passing through the optical fibre channel, the strong correlation after bit reconstruction can still be used in the optical network unit (ONU) for reliable decoding. In the simulation experiments, a 60 Gbit/s bit reconstruction 64 quadrature amplitude modulation (QAM) OFDM signal was successfully transmitted over a 10/20 km single-mode fibre (SMF). The simulation results show that the proposed scheme can effectively achieve reliable transmission with gains of about 1.3 dB and 0.51 dB at a 20% soft decision-forward error correction (SD-FEC) threshold, respectively. The proposed scheme is a promising candidate for a next-generation passive optical network (NGPON) solution.

Construction of Fiber Optical Communication System Infrastructure for 3T (Terdepan, Terluar dan Tertinggal) Areas Using Fiber to the Area Network System

Distribution of telecommunications in Indonesia, the government is aggressively building telecommunications network facilities, especially for 3T areas (Frontier, Outermost and Disadvantaged). Because there are still many areas that have not received access to telecommunications services, the Fiber to The Area (FTTA) network is the right solution to meet the needs of the community in economic, environmental and technical aspects. This design will provide an expansion of Fixed Broadband services around the Tanjung Lesung Special Economic Zone (SEZ), Pandeglang Regency, Banten. Later this fiber optic access network will use a Fiber To The Area (FTTA) network topology that connects the CO (Central Office) as a Metro Ethernet and DWDM hub with the Mini OLT Shelter as an Optical Line Terminal (OLT) hub supported by NG-PON (Next-Generation) PON (Passive Optical Network) technology with 2 Stage architecture which involves two stages of sending information signals through optical fiber. This design must first be designed on Google Earth to determine the fiber optic cable path and to determine the feasibility of performance on the system the author uses several test components including: Link Power Budget (LPB) testing, Rise Time Budget (RTB), Signal to Noise Ratio (SNR), Bit Error Rate (BER), Quality Factor (Q-Factor) which is simulated on optisystem to be able to provide performance values that match the eligibility standards at PT Telkom Indonesia.

Next generation PON architecture using PD-NOMA employing OAM and WDM multiplexing

In this paper, we propose and experimentally demonstrate the efficacy of a next-generation passive optical network (PON) architecture for free space optical link, which utilizes power domain (PD) non-orthogonal multiple access (NOMA) along with simultaneous orbital angular momentum (OAM) mode and wavelength-division multiplexing (WDM) techniques. In this proposed architecture, many optical network units (ONUs) are accommodated by clustering them based on their power budgets and their data streams are allocated with different powers accordingly. The clustered ONUs are served with multiple OAM modes over multiple wavelengths to maintain high capacity, low latency, and increased reliability. As a proof-of-principle experimental demonstration of the proposed architecture, we have experimentally emulated two ONU clusters having a power ratio of (near:far)−3.17dB for implementing the PD-NOMA system for downlink. Each ONU cluster uses three 50 GHz spaced WDM channels, where each WDM channel carries two multiplexed OAM modes having opposite topological charge (l=±1 and ±2) values. Each cluster’s six ONUs is delivered with a 10 Gbps On-Off Keying (OOK) signal. We have demonstrated that all users can achieve a pre-forward error correction (pre-FEC) bit error rate (BER) below the 7% overhead-FEC (OH-FEC) BER limit of 3.8×10−3. We have also measured the x-talk due to WDM and mode multiplexing, and it has been revealed that the main contribution to the power penalty (relative to the no cross-talk condition) comes from OAM mode cross-talk.

Optimization of the Decision Criterion for Increasing the Bandwidth Utilization by Means of the Novel Effective DBA Algorithm in NG-PON2 Networks

In this paper, the reasons for the bandwidth and wavelength utilization in future next-generation passive optical networks are presented, and the possibilities for realization and utilization of extended dynamic wavelength and bandwidth algorithms for the second next-generation passive optical networks (NG-PON2) are analyzed. Next, principles of the effective dynamic bandwidth allocation are introduced in detail, focused on the importance of the decision criterion optimization. To achieve a better bandwidth utilization of dedicated wavelengths in NG-PON2 networks, this paper is focused on the novel effective dynamic bandwidth allocation algorithm with adaptive allocation of wavelengths to optical network units as well as the optimization of the decision criterion. The algorithm and the proposed method are tested and evaluated through simulation with actual traffic data. For analyzing novel extended dynamic wavelength and bandwidth algorithms used for various cases of wavelength allocation in NG-PON2 networks, the effective dynamic bandwidth allocation algorithm analysis is realized in the enhancement of simulation program. Finally, an optimization of the decision criterion defining a minimum bandwidth utilization of the actual wavelength is executed for NG-PON2 networks based on the hybrid time and wavelength division multiplexing technique.

Towards 6G: fast and self-adaptive dynamic bandwidth allocation for next-generation mobile fronthaul [Invited

6G networks will deliver dynamic and immersive applications that bridge the real and digital worlds. The next-generation passive optical access network is a potential optical transport solution for the fronthaul of open radio access networks. With this solution, uplink bandwidth is shared, and uplink latency performance is thus highly dependent on how bandwidth is allocated. Compounding this issue is that future mobile fronthaul (MFH) is expected to support a range of applications that could vary in terms of traffic patterns, bit rates, etc. In view of dynamic network conditions, we present in this paper a machine learning driven dynamic bandwidth allocation scheme that rapidly learns to optimize bandwidth allocation decisions to satisfy uplink latency requirements. The principle of operation of the scheme detailing the reinforcement and transfer learning framework is first described. Performance evaluation results implemented on a target empirical network are then presented. Results show that self-adaptive bandwidth decisions can be rapidly achieved in response to different traffic patterns, network loads, and line rates, consolidating the potential of the dynamic allocation scheme in supporting diverse applications in future MFH networks.

100 Gbit/s PAM-4 Linear Burst-Mode Transimpedance Amplifier for Upstream Flexible Passive Optical Networks

Next-generation passive optical networks (PONs) with upstream rates of 50 Gbit/s and beyond will require a new class of burst-mode transimpedance amplifiers (BMTIAs) that are linear to enable (digital) equalization of channel impairments. Such linear BMTIAs also enable higher-order modulation formats like 4-level pulse amplitude modulation (PAM-4). In this paper, we demonstrate operation of a novel linear BMTIA integrated together with a commercial off-the-shelf 25G-class avalanche photodiode (APD), achieving 50 Gbit/s non-return-to-zero (NRZ) operation with a sensitivity of -23.7 dBm optical modulation amplitude (OMA) and dynamic range exceeding 21.7 dB and 100 Gbit/s PAM-4 operation with a sensitivity of -15.8 dBm OMA and dynamic range exceeding 15.4 dB, both at a bit error ratio (BER) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$10^{-2}$</tex-math></inline-formula> . In addition, fast burst-mode gain-control and balancing circuits limit loud-soft sensitivity penalties in the case of AC-coupled circuits to less than 1.3 dB. The chip was designed in a 0.13 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> m SiGe:C BiCMOS technology, has an area of 1.2×1.7 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{2}$</tex-math></inline-formula> and consumes between 260 mW and 310 mW. This receiver paves the way to a next-generation class of BMTIAs, supporting the ITU-T G.9804.3 Amd 1 standard.

Multi-Tone Optical Source Generation for Applications in Next-Generation Passive Optical Networks using Photonic Structures

This study presents the design and simulation of an integrated multi-carrier optical source with a 227 GHz bandwidth for passive optical network (PON) applications. The optical comb generation attained using a photonic structure known as a micro-ring resonator fabricated in silicon nitride (Si3N4) facilitates cost reduction when produced on a large scale. Additionally, the generated optical comb accomplishes non-uniform tones in terms of the optical signal-to-noise ratio (OSNR), which allows for the dynamic assignment of carriers to retainable customers as a function of the data rate and transmission distance requirements. The design and simulation demonstrate the generation of frequency combs with optical carriers in a range of 5-40 tones, an OSNR range of 20-80 dB, and a free spectral range (FSR) of 50-3 610 GHz. To achieve these features, a geometric design of the device is proposed, and its response to variations of input laser parameters is described. In summary, the device uses two optical micro-resonators with radii of 100 and 450 µm and controls the power and the tuning of laser parameters. The proposed method allows generating a deterministic and reliable path to the frequency combs. Finally, the characteristics of the obtained combs are tested to determine their potential use in PON transmissions.

400-Gbps/80-km Rate-Flexible PCS-64-QAM WDM-CPON With Pseudo-m-QAM Chaotic Physical Layer Encryption

For next-generation high-capacity, rate-flexible, and secure 400-G passive optical network (PON), a scheme joint wavelength division-multiplexed (WDM), entropy-regulated probabilistic constellation shaping-64-quadrature amplitude modulation (PCS-64-QAM) and chaotic encryption mapping, is proposed and demonstrated. For the first time, chaotic encryption is realized over the PCS-based PON with the architecture from one optical line terminal (OLT) to multiple optical network units (ONUs). Chaotic encryption with an initial-value-sensitive feature can generate a large amount of parallel encrypted sequences which provide a key pair corresponding with every possible entropy/rate. A novel mapping from PCS-64-QAM with various entropies to pseudo- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</i> -QAM is designed, which erases the entropy information of the link and encrypted the original information of the sequence. The encryption transmission is demonstrated over a real-time dual-polarized coherent optical platform with an 80-km link and typically one-to-many PON configuration, and a net 211.80∼348.12-Gb/s rate result within the hard-decision forward error correction (FEC) threshold is achieved for 6λ × 2 ONUs group. The rate of each polarization state can be tuned in a minimum 3.408-Gbps step in the demonstration. Expanding from the basis of the original WDM-CPON, this work prepares an adapted chaotic encryption scheme for large-scale access. Overall, our proposed scheme can provide an abundant system loss budget, a large rate tunable range, and basic physical layer security for next-generation rate-flexible coherent PON (FLCS-CPON).

Architecture and key digital signal processing techniques of a next-generation passive optical network [Invited

A passive optical network (PON) with low cost and high capacity has been explored and recommended for supporting the emerged commercial mobile fronthaul, resident, and industry services. To meet the requirement in the future, the development of the PON, including cost, data rate, and latency, is still being driven by utilizing an improved PON architecture, transmitter, and receiver. In this paper, we review the results of our recent work that focused on the promising solution for the next-generation passive optical network, which mainly includes three aspects: (1) a new uplink PON architecture with a laser sharing technique based on filter bank multicarrier is investigated to provide high spectrum efficiency uplink access for multiple asynchronous users; (2) a transmitter with a low-resolution digital-to-analog converter is explored for the uplink of the PON with advanced modulation formats, and a low computational complexity noise shaping technique is utilized to eliminate the quantization noise; and (3) for the receiver, a sub-Nyquist sampling reception technique based on optical arccos function shaping is investigated, which enables optical network units to receive high-rata aggregated data with a low-speed analog-to-digital converter.

Time-variant entropy regulated multiple access for flexible coherent PON.

To further increase the data rate and rate flexibility of next-generation passive optical networks (PONs), we propose a scheme jointing probabilistic constellation shaping (PCS), constellation diagram identification, and coherent detection. The rate of the coherent PON is dynamically regulated with time-variant entropy, and monitored by the image classifier in real-time. The transmitted cascade frames allocated to different optical network units (ONUs) from the optical line terminal (OLT) can be synchronized, identified, and distinguished by the labeled entropy values. The proposed graphic monitoring scheme is experimentally demonstrated based on a dual-polarized coherent optical transmission system. A 0.5 interval value of entropy is precisely tuned to achieve a 96.13% constellation identification accuracy for entropy/rate by a fast normalized cross correlation coefficient (NCC)-based image classifier. A real-time data rate from 350 to 550 Gb/s with PCS-64-quadrature amplitude modulation (64-QAM) format for a single ONU is achieved which can maximally support five independent ONUs with single wavelength and two polarization states and the entropy varying from 3.5 to 5.5 with 0.5 intervals, respectively.

High-security SCMA-OFDM multi-core fiber transmission system based on a regular hexagon chaotic codebook.

Sparse code multiple access (SCMA), a new code-domain non-orthogonal technology in the fifth-generation mobile communication (5G), can be modulated by orthogonal frequency division multiplexing (OFDM) to improve the link quality of a single user. In this paper, a high-security SCMA-OFDM multi-core fiber transmission system based on a regular hexagonal chaotic codebook is proposed for next-generation passive optical network (PON). The whole encryption process consists of a regular hexagon chaotic codebook design and frequency domain block scrambling. In designing the regular hexagon chaotic codebook, the optimization of constellation points on orthogonal resources are considered as the starting point. Firstly, the chaos factor generated by the four-dimensional Rossler chaos model is deployed to disturb the mother constellation, and then the corresponding chaotic book is formed by rotating the mother constellation and multiplying the sparse matrix. The designed codebook logically avoids the degradation of transmission performance caused by the rough scrambling of codebook constellation, to find a balance between codebook disturbance and bit error rate (BER). The security and reliability of the transmission system have been verified by performing 42 Gb/s encrypted SCMA-OFDM data transmission experiments in a 2km multi-core fiber. The key space of the encryption scheme can reach 10178, which effectively ensures the security of the transmission system. Furthermore, the performance of the transmission system with a regular hexagon chaotic codebook is improved by 2.5 dB compared with the traditional codebook when the BER is 1 × 10-3. Moreover, the SCMA-OFDM-based transmission architecture and the detection effects of different multi-user detection algorithms in the SCMA-OFDM multi-core fiber transmission system are also studied.

High-security and low-complexity OCDM transmission scheme based on GAN enhanced chaotic encryption.

We report a low-complexity and high-security orthogonal chirp division multiplexing (OCDM) transmission scheme based on generative adversarial networks (GAN) enhanced chaotic encryption. Our investigation focuses on the security and efficiency of the communication system. To successfully apply GAN for the encryption scheme, we design our networks with new network architectures and modify the loss functions to improve the adversarial training performance of the networks. In the experiment, a weakly coupled seven cores fiber of 2 km was applied to achieve a 70 Gb/s transmission system. The results reveal that our proposed scheme has a maximum receiver sensitivity gain of about 1.26dB than traditional OFDM transmission system, and our encryption scheme has a large keyspace at about 1 × 10202 against brute force cracking by illegal optical network units with only 0.63% running time compared with the traditional chaotic scheme. The results highlight that the proposed encryption scheme has a remarkable reduction in complexity and improvement in security, which is a promising candidate for next-generation PONs.

Flexible energy-efficient and direct intra-ODN/OPN communication capable TWDM PON architecture with centralized OLT sharing among multiple optical networks

Nowadays, service reliability, operation cost, transmission latency of optical access networks are the major challenging issues that need to be addressed while planning and developing the next-generation passive optical networks (NG-PONs). This paper proposes a flexible, energy-efficient, time and wavelength division multiplexed (TWDM) PON architecture that has the capability of centralized optical line terminal (OLT) resource sharing with multiple optical networks. The architecture has the point-to-point direct inter-optical networking unit (dedicated inter-ONU) transmission capability among the various ONUs located within the same optical distribution network (ODN). Such transmission may also be referred to as direct intra-ODN communication. The architecture also has the potential of transmitting an inter-ONU signal to the ONUs residing in the different ODNs (inter-ODN) belonging to the same optical network (OPN). Such transmission may be referred as the direct inter-ODN or intra-OPN transmission. The architecture reduces the normalized energy consumption of approximately 2.21875 Wh per hour, normalized transmission latency of approximately 148 µs for the direct inter-ONU transmission. This is achieved by diverting the inter-ONU signal from the remote nodes (RNs) itself towards the intended ONUs. The percentage energy saving of the proposed architecture is approximately 74 % as compared to the conventional architecture. The proposed architecture is suitable for strengthening the existing information and communication technology (ICT) infrastructures and can be implemented in next-generation flexible, energy-efficient, latency-aware, and reliable optical networks for developing smart rural and urban communities.

Performance-Enhanced Optical Non-Orthogonal Multiple Access Enabled by Orthogonal Chirp Division Multiplexing

In this paper, we propose a novel optical non-orthogonal multiple access (NOMA) scheme based on orthogonal chirp division multiplexing (OCDM) in a low-cost intensity modulation and direct detection system for passive optical networks (PON). The proposed OCDM-NOMA scheme can effectively improve spectral efficiency and serve more users by multiplexing spectrally overlaid OCDM signals in power domain. Under the advantages of the chirp spread spectrum, the proposed OCDM-NOMA scheme can also enhance the bit error rate (BER) performance compared to NOMA scheme based on orthogonal frequency division multiplexing (OFDM). A 17.8 Gb/s OCDM-NOMA PON transmission over 25 km standard single-mode fiber is experimentally demonstrated. The results show that, when compared to OFDM-NOMA and precoding OFDM-NOMA, OCDM-NOMA can achieve receiver sensitivity gains of 1.3 dB and 0.5 dB for the high-power branch signal, and 1.4 dB and 0.6 dB for the low-power branch signal at a BER of 3.8×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> . Furthermore, we investigate the feasibility of using higher-order modulation in NOMA technology for the first time to further improve data throughput and spectral efficiency. In a 22.2 Gb/s transmission, the optimal power division ratio is determined, and the transmission performance is investigated. According to the experimental results, OCDM-NOMA with higher-order modulation can be a promising candidate for next-generation PONs.