With the large-scale deployment of F5G all-optical networks, Passive Optical Network (PON) technology has expanded from traditional residential broadband access to core scenarios in various vertical industries, including smart transportation, mining and chemical industries, water conservancy and environmental protection, and campus intelligentization. In the end-to-end implementation of PON networks, power supply for edge devices has long been a widely recognized core pain point in the industry: conventional Power over Ethernet (PoE) is limited to a 100-meter transmission distance, making it unable to adapt to long-distance distributed sites; mains power wiring faces multiple challenges such as high construction costs, long construction cycles, high risks of lightning damage and explosion hazards, and difficult O&M.
Against this backdrop, Power On Fiber (POF, also referred to as fiber optic power feed technology)has emerged as a key technical solution to address the pain points of PON edge power supply, with its core features of native compatibility with PON networks, long-distance transmission, and intrinsic safety. This article provides a comprehensive analysis of the industry application practices of POF technology from the dimensions of technical principles, core features, implementation scenarios, and selection specifications.
First, it is necessary to clarify that the POF described in this article, with the full name Power On Fiber, is an integrated technology for optical power transmission and data communication based on optical fiber media. It is a completely independent technical system from the Plastic Optical Fiber (POF) commonly mentioned in the industry, and there is no correlation between the two.
In terms of technical essence, POF is an extension and innovation of PoE technology in the field of optical communications. Its core logic is to simultaneously transmit PON service data optical signals and power supply pump laser in the same optical fiber through Wavelength Division Multiplexing (WDM) technology, realizing co-fiber bidirectional transmission of data communication and remote power supply without additional power cable deployment.
POF technology is fully developed based on the standard architecture of existing PON networks. It does not require replacement of passive components such as optical fibers and optical splitters in the existing Optical Distribution Network (ODN), and is natively compatible with the full series of PON standards including GPON, EPON, XG-PON, and XGS-PON. Its core working link is divided into three closed-loop stages:
Central Office Multiplexing and Optical Power Injection: On the Optical Line Terminal (OLT) side in the central office, a dedicated POF pump optical module and WDM multiplexing unit are used to combine the pump laser compliant with ITU-T standards (in the industry-standard 1480nm/1550nm low-loss window band, with wavelengths completely isolated from PON service wavelengths) with PON service data optical signals into the same single-mode optical fiber.
Passive Optical Link Transmission: The combined optical signal is transmitted through the ODN link (optical fibers, passive optical splitters, optical connectors, etc.) of the existing PON network. There are no active components throughout the link, which fully matches the passive characteristics of the PON network, and no additional power supply or on-site maintenance is required.
Remote End Demultiplexing and Photoelectric Conversion: At the edge site, the service data optical signal and the power supply pump laser are separated by a WDM demultiplexing unit: the service data optical signal enters the Optical Network Unit (ONU) to complete data communication, while the power supply pump laser enters a dedicated photoelectric conversion module (high-sensitivity photovoltaic cell based on the photovoltaic effect), which converts the laser energy into stable DC power to supply power for edge devices such as ONUs, IP cameras, sensors, and access control devices.
In particular, the power supply wavelength adopted by POF technology is in a completely isolated optical window from the PON service wavelength, without any crosstalk between the two. It will not have any impact on the bandwidth, latency, and transmission stability of PON services, and fully complies with the ITU-T G.984, G.987 and other international PON series standards.
Compared with traditional edge power supply solutions, the core advantage of POF technology is that it perfectly adapts to the native characteristics of PON networks and solves the scenario pain points that cannot be covered by traditional solutions. The core implementable technical features are as follows:
Native Compatibility with PON Networks, 100% Reuse of Existing Assets
POF technology is fully designed based on the existing standard PON architecture. There is no need to replace existing equipment such as the central office OLT, edge ONUs, ODN optical fibers and optical splitters. It can be quickly deployed only by adding a POF multiplexing unit at the central office and a photoelectric conversion module at the edge end, maximizing the reuse of existing network assets and greatly reducing the investment cost of renovation and new projects.
Long-Distance Synchronous Transmission, Breaking Through Distance Boundaries
The maximum transmission distance of conventional PoE power supply is 100 meters, which cannot adapt to long-distance distributed sites; while the transmission distance of POF technology is fully matched with the PON network, up to 20km, which perfectly covers the full-link power supply requirements of the PON network, and fundamentally solves the power supply problem of remote distributed sites.
Intrinsically Safe Design, Adaptable to High-Risk Explosion-Proof Scenarios
POF technology only transmits optical signals throughout the link without any current transmission, and the optical fiber medium itself is an insulating material, which fundamentally eliminates safety risks such as electric leakage, electric sparks, and short circuits. Its intrinsically safe design complies with explosion-proof standards such as GB3836 and IECEx, and can be directly applied to Class I and Class II high-risk explosion-proof scenarios such as underground coal mines, chemical industrial parks, and oil and gas fields, greatly reducing the wiring approval difficulty and safety management and control costs in explosion-proof scenarios.
Strong Anti-Interference and Lightning Protection Capability, Improving System Stability
Traditional copper cable power supply and data transmission solutions are extremely vulnerable to strong electromagnetic interference, and copper cables will induce lightning current, resulting in frequent damage to edge devices and high O&M costs. The all-optical link of POF is completely non-conductive, immune to any electromagnetic interference, and at the same time fundamentally eliminates the intrusion path of induced lightning, which can reduce the lightning failure rate of edge devices by more than 90%, greatly improving the long-term operation stability of the system, especially suitable for outdoor, mountainous, power plants, steel mills and other strong interference and high lightning risk scenarios.
Full-Link Passive Design, Reducing Full-Life Cycle O&M Costs
Consistent with the PON network, the transmission link of POF has no active components and no wearing parts throughout the process, and no on-site maintenance is required. Compared with power supply solutions such as solar energy and mains power, it greatly reduces the long-term O&M costs, especially suitable for unattended remote sites.
At present, POF technology has achieved large-scale implementation in PON network projects in multiple domestic industries, and the core application scenarios are concentrated in fields that cannot be effectively covered by traditional power supply solutions. The typical scenarios are as follows:
Scenario Pain Points: Video surveillance, checkpoints, and incident detection devices along expressways, national and provincial highways, and tunnels are distributed in scattered sites, mostly in mountainous and field areas 3-20km away from the central office, with no mains power coverage. Traditional mains wiring requires separate erection of utility poles, resulting in high construction cost per site and long construction cycle. At the same time, copper cable power supply is extremely vulnerable to lightning strikes, resulting in high equipment damage rate and difficult O&M.
POF Solution: Based on the existing PON communication network along the highway, a POF pump multiplexing unit is added to the OLT side in the equipment room, the existing ODN fiber link is reused, and a WDM demultiplexing unit and POF photoelectric conversion module are installed at the remote surveillance site to simultaneously provide data link and power supply for cameras, ONUs and other equipment, without separate mains line deployment.
Implementation Value: The construction cost per site is reduced by more than 30%, the construction cycle is shortened by 50%, the lightning failure rate of equipment is reduced by more than 90%, and the full-life cycle construction and O&M costs are greatly reduced.
Scenario Pain Points: Scenarios such as underground coal mines, chemical industrial parks, and oil and gas fields have strict requirements on the explosion-proof grade of equipment and wiring. Traditional copper cable power supply has safety risks of electric sparks and electric leakage, the wiring cost of explosion-proof cables is high, and the approval process is complicated. At the same time, the equipment sites in underground mines and chemical parks are scattered, making it difficult for traditional power supply solutions to achieve flexible coverage.
POF Solution: Based on the PON industrial ring network in underground mines/parks, POF technology is used to realize simultaneous data and power transmission over the all-optical link. There is no current transmission in the whole link, which is intrinsically safe. There is no need to lay explosion-proof cables, which simplifies the approval process, and adapts to the power supply requirements of explosion-proof ONUs, sensors, monitoring and other equipment underground.
Implementation Value: The wiring cost in explosion-proof scenarios is reduced by more than 40%, the approval process is greatly simplified, the potential electrical safety hazards are fundamentally eliminated, and the safety level of the production system is improved.
Scenario Pain Points: Hydrological monitoring, water quality detection, weather stations, forest fire prevention monitoring sites in reservoirs, rivers, lakes and mountainous areas are generally located in remote areas without mains power. Traditional solar power supply is greatly affected by weather such as rain, fog and haze, resulting in insufficient power supply stability and high maintenance cost of battery replacement. The sites are generally 5-20km away from the equipment room, which cannot be effectively covered by traditional solutions.
POF Solution: Based on the PON network of the water conservancy and environmental protection private network, POF technology realizes remote power supply from the equipment room more than ten kilometers away, which is not affected by the weather, has stable and reliable power supply, and provides stable power and data links for monitoring sensors, Remote Terminal Units (RTUs), ONUs and other equipment.
Implementation Value: The system power supply stability is increased to 99.99%, there is no need for regular battery replacement and on-site maintenance, and the annual O&M cost is reduced by more than 60%.
Scenario Pain Points: In the intelligent renovation of old campuses and old residential communities, PON fiber lines have been pre-buried, but no power supply pipelines for edge devices are reserved. When adding surveillance, access control, and IoT devices, the construction of wall breaking and pipe threading is difficult, costly, and has a long cycle, which affects the normal life of residents.
POF Solution: Reuse the existing pre-buried PON fiber lines without re-wiring. Only need to add POF modules at the equipment room side and photoelectric conversion modules at the edge end to provide power supply and data links for new equipment, realizing non-intrusive renovation.
Implementation Value: The renovation construction cycle is shortened by more than 60%, no wall breaking and wiring is required, the renovation cost is reduced by more than 40%, and the construction difficulty of the renovation and the impact on users are greatly reduced.
To ensure the stable operation of the POF system, the following core specifications must be followed in the project selection and construction process to avoid common engineering risks:
Priority on Compatibility of Wavelength Planning
The power supply wavelength of POF must be completely isolated from the service wavelength of the existing PON network to avoid optical crosstalk affecting service quality. For example, in a GPON network, it is necessary to avoid the 1310nm upstream and 1490nm downstream service wavelengths, and give priority to the 1480nm or 1550nm power supply band; in a 10G PON network, it is necessary to simultaneously avoid the 1270nm upstream and 1577nm downstream service wavelengths to ensure no overlap in wavelength planning.
Accurate Calculation of Link Optical Power Budget
The power supply efficiency of POF is strongly correlated with the insertion loss of the ODN link. In the project design stage, it is necessary to accurately calculate the full-link loss including optical fiber link loss, optical splitter insertion loss, and optical connector loss, and reserve sufficient optical power budget in combination with the power demand of the end device and the conversion efficiency of the photoelectric conversion module (the industry mainstream level is 40%-50%) to ensure the stability of the end power supply.
Compliance Requirements for Device Selection
The WDM multiplexing/demultiplexing units, pump optical modules, and photoelectric conversion modules used in the POF system must comply with the relevant ITU-T optical standards. At the same time, the compatibility with existing OLT and ONU equipment must be verified in advance to avoid compatibility problems. In explosion-proof scenarios, the devices used must have explosion-proof certification for the corresponding scenarios and strictly comply with industry safety specifications.
Strict Implementation of Construction Specifications
The construction of the POF system must follow the construction specifications of optical communication engineering to ensure the quality of optical fiber fusion splicing and connector fabrication, and control the additional link loss. At the same time, the bending radius of the optical fiber must meet the standard requirements to avoid additional loss and optical power attenuation caused by excessive bending, which affects the power supply effect.
With the in-depth penetration of F5G all-optical networks into all walks of life, the coverage boundary of PON networks is extending from traditional broadband access to more vertical industry scenarios such as industrial control, urban security, ecological monitoring, and emergency communications. The demand for long-distance, safe and reliable power supply for edge devices is growing rapidly.
As an edge power supply solution natively compatible with PON networks, POF technology is not a replacement for traditional power supply solutions such as PoE, but an effective complement to its capability boundaries, perfectly covering scenarios that cannot be reached by traditional solutions, such as long-distance, high-risk, no mains power, and strong interference. In the future, with the continuous improvement of photoelectric conversion efficiency and further reduction of device costs, POF technology will become one of the core standard capabilities of F5G all-optical network edge power supply, providing a more stable, safer and more economical infrastructure support for the all-optical transformation of all walks of life.
