Comparison of Fiber Technologies XGS-PON and NG-PON2

Gezhi Optical Fiber's XGS-PON

XGS-PON is a newer Passive Optical Network (PON) standard capable of supporting higher speed 10 Gbps symmetrical data transmission and is part of a family of standards known as Gigabit-capable PON (G-PON). G-PON stands for Gigabit PON or 1 Gigabit PON. "X" represents the number 10 in XGS, and the letter "S" represents symmetry, XGS-PON = 10 Gigabit symmetric PON. The previous version of asymmetric 10 Gigabit PON (XG-PON) was limited to 2.5 Gbps in the upstream direction.

PON technology originated in the 1990s and has evolved through multiple iterations, with different wavelengths, speeds and components appearing as the technology advances. The common feature of all optical fiber PON networks is still the passive or passive state of the optical fiber and its splitting or combining components, that is, there are no active components that require power, such as optical amplifiers, in the network. The development of XGS-PON and other standards has proven necessary as emerging technologies such as streaming, HD, and 5G continue to drive bandwidth demands.

Through wavelength division multiplexing (WDM), simultaneous uplink and downlink transmission can be performed on the same optical fiber. This technology allows optical transmission of one XGS-PON wavelength or color for upstream and another for downstream.

standard

Since its initial adoption, standardized PON deployment and operation have been achieved through standards developed by the International Telecommunication Union (ITU) for the G-PON family, and through standards developed by the Institute of Electrical and Electronics Engineers (IEEE) for Ethernet PON, or "EPON." Finish. The new XGS-PON standard was released in 2016 and was designated as recommendation ITU-T G.9807.1.

The scope of the new standard defines XGS-PON as a 10-Gigabit-capable symmetric passive optical access network for residential, commercial, mobile backhaul and other applications. To create a comprehensive standard for the evolution of symmetrical 10-Gbps G-PON, elements of the earlier XG-PON physical layer standard were adopted, meaning that the same optical transceiver components can be used for either XG or XGS-PON. The protocol layer standard is also used for reference in the NG-PON2 standard, ITU-T G.989.3.

wavelength

Although the physical fiber and data formatting conventions of the XGS-PON technology remain the same as the original G-PON standard, the wavelengths have changed. The downstream wavelength of XGS-PON is 1577 nm, and the upstream wavelength is 1270 nm. The main reason for this is to allow multiple PON services to coexist on the same PON to seamlessly upgrade/migrate services, or to allow different service providers to use the same PON, or to provide different levels of service (e.g. commercial and residential). The wavelength of XGS-PON is different from other standards such as G-PON and NG-PON2, although the total PON transmission window is 1260 to 1650 nm, which can simultaneously accommodate G-PON, XGS-PON and NG-PON2 standards on the same fiber network . Because XGS-PON is an update of the XG-PON standard to provide symmetrical capacity, both XG and XGS-PON use the same wavelength for uplink and downlink, which is the only case where the same wavelength is multiplexed. Today, most operators considering deploying 10G services have chosen XGS-PON.

how to measure

The evolution of PON networks requires the improvement and adaptability of PON test tools. Traditional fiber optic test tools, including OTDRs, light sources, and broadband power meters can be used effectively but may have limitations. For example, a wideband power meter cannot be used to measure downstream optical power levels if multiple optical wavelengths are present, either because RF video is superimposed (broadcast) on the same PON, or due to multiple PON services co-existing on the same PON ( such as G-PON and XGS-PON). The downlink wavelength is broadcast continuously, which makes the measurement easier. However, since the physical uplink path of PON is shared, time division multiplexing (TDM) method is required for uplink wavelength transmission, resulting in the burstiness of uplink traffic. In addition, if the subscriber's device cannot receive the downstream wavelength first, it will only answer and transmit upstream, so measuring upstream power also requires tools that support burst mode measurements and transparent mode operation.

A dedicated PON power meter is a useful and versatile tool for determining whether upstream and downstream transmit power is within specification, whether optical insertion loss exceeds system limits, and is compliant. Since the use of different transmission wavelengths is a key component of XGS-PON technology, equipment capable of filtering and selecting the appropriate wavelength for measurement is required. Gezhi Photonics’s PON power meter solves the challenges of PON testing by providing wavelength-selective power measurement. Some devices also have transparent transmission mode capabilities, which are suitable for online network service activation or troubleshooting.

True PON tester of Gezhi Photonics Co., Ltd.

The True PON Tester is a wavelength-selective passive optical network (PON) power meter with TruePON PON-ID analysis. Wavelength selectivity ensures that individual downstream wavelengths are accurately measured to prevent installation at tipping points. Simultaneous measurement of a single PON wavelength is absolutely necessary when there are multiple services on the same PON, as part of a service upgrade or migration plan, as a coexistence model. TruePON PON-ID analysis provides OLT port serial number, ODN category and OLT downlink transmit power, applicable to G-PON and XGS-PON services. The OLT serial number enables technicians to confirm or locate the correct drop port for configured customer services and prevents time wasted when reconfiguring services to other OLT ports. Reading OLT transmit power allows for in-service loss measurements to avoid critical installations, or to troubleshoot existing installations to determine the cause of low power levels. The SmartPocket V2 OLP-39 True PON Tester is an easy-to-use, dedicated and cost-optimized solution for testing, installing and troubleshooting G-PON and XGS-PON services, while the rugged and compact form factor is ideal for field use.

True PON tester for G-PON, XGS-PON and hybrid systems.

SmartClass Fiber OLP-87 PON Power Meter

Symmetrical transport over PON networks makes combining downstream and upstream testing for PON activation, troubleshooting or maintenance activities a beneficial strategy. SmartClass Fiber OLP-87 PON Power Meter has been designed to test both upstream and downstream of B/E/G-PON services, including XGS-PON, 10G EPON or NG-PON2. The device features an advanced and versatile wavelength-selective power meter and transparent mode capability (including upstream burst mode support) to measure multiple upstream and downstream wavelengths simultaneously. The integrated fiber inspection capability also enables quick and easy inspection and certification of fiber end faces, and reports can be saved conveniently and reliably for recall at any time.

SmartClass Fiber OLP-87 PON Power Meter

XGS-PON vs NG-PON2

Some see the NG-PON2 standard as the next logical step in increasing service and network capacity, but it brings with it inherent challenges and potential for enhancement. NG-PON2 uses time and wavelength division multiplexing (TWDM) to allow four or more simultaneous 10 Gbps transmissions on the same fiber for a total symmetrical capacity of 40 Gbps. This technology differs significantly from XGS-PON, which, like its predecessor, the G-PON iteration, switches between dedicated upstream and downstream wavelengths. However, the implementation of NG-PON2 may involve more complexity and high equipment and network upgrade costs.

When deciding to use XGSON2, service providers need to consider various factors, including implementation costs, maintenance requirements, upgrade roadmap and network requirements.

NG-PON2 could be an attractive option for service providers looking to deliver higher bandwidth over fiber optic networks. NG-PON2 can provide data transmission speeds up to 40Gbps, while XGS-PON can only provide 10Gbps. However, the implementation of NG-PON2 may involve more complexity and high equipment and network upgrade costs. This may include purchasing and installing new network equipment, as well as training technicians to maintain and operate new equipment and systems.

On the other hand, XGS-PON may be a better choice for those service providers who want to provide high-speed fiber services while reducing operating costs as much as possible. Although XGS-PON is not as fast as NG-PON2, it can provide comparable performance and can be more easily integrated with existing PON equipment.

In general, service providers need to consider their specific business needs and goals when choosing XGS-PON or NG-PON2. Some companies may prioritize offering the highest speed and maximum bandwidth, while others may prioritize cost-effectiveness and ease of use.