FBG fiber optic reflector, also known as Fiber Bragg Grating Filter, is usually installed on the front end of the ONU. Combined with OTDR equipment, it can realize the point-to-point (PTP) or point-to-multipoint (PTMP) network monitoring of optical link, which can reflect the network abnormality quickly and accurately.
What is FBG? FBG is Fiber Bragg Grating. A fiber grating is a type of diffraction grating. Fiber Bragg Gratings (FBG) is a simple and low-cost way to build a grating into a specific wavelength range of fiber. When broad-spectrum light is incident on the fiber with built-in grating, the wavelength matching the grating will be reflected back to the input end, and the rest of the light will be passed through to the other end. Fiber gratings have the characteristics of small size, good wavelength selectivity, good compatibility, etc. The manufacturing process for fiber gratings is mature, with good practicality and low cost, they are widely used in the field of communication and sensing and is also ideal important device in optical network.
The FBG optical reflector utilizes the wavelength selectivity of the fiber grating, and the fiber grating is embedded in the adapter. It can be conveniently installed on the front end of an optical network (ONU), and it can quickly and accurately implement optical network fault detection with the help of an optical time domain reflector (OTDR). Due to the excellent wavelength selection characteristics of fiber gratings, anti-electromagnetic interference, the center wavelength drift is small with the change of external temperature, and when the optical network coverage and depth continue to increase, the entire optical network fault point can be detected quickly and accurately.
With the application of optical splitters in passive optical network (PON) networks, the complexity of the ODN network deployment environment has been increased. The splitters at the end of the FTTx will split the trunk optical signals and increase the difficulty to identify attenuation events on ODN branch fibers. The application of fiber grating reflector is a wavelength selective reflector based on this environment, which aims to improve the fast and accurate detection of optical link failure events by OTDR.
The fiber optic reflector is usually installed on the ONU side. The OTDR detects the intensity of the optical signal reflected by this reflector and compares the return loss between the normal line and the failed link to determine whether the optical fiber in the link is damaged or not. The normal PON system working wavelength does not meet the reflector conditions then will pass through the reflector with a small attenuation. While the reflector achieves the monitoring function, but without disturbing the transmit. 1650nm fiber grating reflector, the grating reflection wavelength is 1645 ~ 1650nm. The optical signal in this Bragg wavelength range will return along the input path, and all other wavelengths of light (1260 ~ 1625nm) can pass through. If the input optical signal segment can detect the fiber grating reflection peaks in this band, it can be judged that the transmission path is normal. Otherwise, it is abnormal.
End-to-end OTDR measurement from the OLT to the ONT is usually difficult because the splitter brings high losses and complex networks. The application of fiber optic reflector is a cost-effective solution to help OTDR detection, and it is the best way to implement real-time end-to-end (OLT to ONT) monitoring of optical networks in FTTx networks.
HYC's self-developed FBG fiber optic reflector has the advantages of low insertion loss, high reflectivity, and easy installation. It is widely used in PON networks, OTDR testing, central computer room testing, FTTX and other fields. It can be customized as special pigtail or adapter type, and the connector interface is LC, SC APC / PC.
About HYC
HYC Co., Ltd is a leading OEM / ODM and solution provider of optical passive devices in the industry, focusing on R&D, design, manufacturing, sales and service of passive devices for optical communication. HYC has an international R&D and operation team, advanced automated production and testing equipment, and an information-based lean operation system, with excellent design and development capabilities, large-scale organization and production capacity, quality control capabilities, providing high stability, cost-effective, and leading technology products.