Introduction of Fiber Optic Adapter
1. What is a fiber optic adapter
Optical fiber adapters (also known as flanges), also known as optical fiber connectors, are the central connection parts of optical fiber active connectors. Optical fiber connectors are the most widely used optical passive components in optical fiber communication systems. Most optical fiber connectors are composed of three parts: two optical fiber connectors and a coupler. Two optical fiber connectors are installed into the two optical fiber tail ends; the coupler plays the role of aligning the sleeve. In addition, the coupler is mostly equipped with a metal or non-metal flange to facilitate the installation and fixing of the connector.
Both ends of the fiber optic adapter can be inserted into fiber optic connectors of different interface types to realize the conversion between different interfaces such as FC, SC, ST, LC, MTRJ, MPO, E2000, etc. It is widely used in optical distribution frames (ODF), optical fiber communication equipment, Instruments, etc., with superior performance, stable and reliable. Some fiber optic adapters on the market are also called fiber optic connectors. In fact, these are two different products.
2. Features of Fiber Optic Adapter
- Through 100% optical performance testing, the ceramic (zirconia) sleeve is processed by imported high-precision machine tools, with high product finish and precise axis positioning to ensure the precise coefficient of coaxiality and concentricity of the product
- The integrated internal structure is uniquely designed, the structure is simpler, the use is easier, the assembly is easy, and the efficiency is improved
- Good stability performance, small insertion loss in continuous plugging and unplugging test
Three, fiber optic adapter performance indicators
Insertion loss: ≤0.2dB
Return loss: ≥40dB
Interchangeability: ≤0.2dB
Working temperature (°C): -30―+80
Storage temperature (°C): -40―+85
Vibration test: ≤0.1dB (10-60Hz, 1.5mm amplitude)
Tensile strength test: ≤0.1dB
Repeatability: ≥1000 times
4. Classification of fiber optic adapters
There are various types of fiber optic connectors. The connectors generally used in EPON networks are APC connectors. The end face of APC is ground into an 8-degree angle to reduce reflection. The industry standard return loss is -60dB . Featuring precise, predetermined angles, predetermined radii, and pre-polished ferrules, APC connectors provide superior performance and can be used with compact key configurations with or without NTT-FC standards.
According to the application range and requirements of fiber optic adapters, in order to fix on various panels, fiber optic adapters are also designed with a variety of fine fixing flanges. Transition fiber optic adapters can connect to different types of fiber optic jumper interfaces and provide different The connection between sections, double or multiple connections can increase the installation density. According to the shape structure and docking section, fiber optic adapters can be roughly divided into the following common types: FC, SC, ST, LC, FC-SC, FC-ST, ST-SC, in addition to some male-to-female adapters Connect to the fiber optic adapter.
FC fiber optic adapter:
The external strengthening method is a metal sleeve, and the fastening method is a turnbuckle. The FC type connector adopts the butt end of the ceramic pin. This type of connector is simple in structure, easy to operate, and easy to manufacture, but the fiber end is more sensitive to dust and prone to Fresnel reflection, making it difficult to improve return loss performance. Later, this type of connector was improved by adopting a contact pin (PC) with a spherical butt end surface, and the external structure remained unchanged, which greatly improved the insertion loss and return loss performance.
SC fiber optic adapter:
Its shell is rectangular, and the structure dimensions of the pins and coupling sleeves used are exactly the same as those of the FC type. Among them, the end faces of the pins are mostly PC or APC-type grinding; the fastening method is the plug-in pin-bolt type, which does not need to be rotated. Equipped with metal shrapnel, it is convenient for concealed installation. This type of connector is cheap, easy to plug and unplug, has small fluctuations in insertion loss, high compressive strength, and high installation density.
ST fiber optic adapter:
It is a snap-on locking structure with a key to ensure accurate alignment during connection. It has strong tensile strength. The metal key is positioned to improve the repeatability and durability of the adapter. It uses a precision ceramic or copper sleeve to ensure Long-term stable mechanical and optical properties. Rectangular structure, easy to install and use by tapping and riveting.
LC fiber optic adapter:
Made with an easy-to-operate modular jack (RJ) latch mechanism. The size of the ferrule and the sleeve adopted is small, and the density of the optical fiber connector in the optical fiber distribution frame is improved. Adopt precision ceramic sleeve to ensure long-term stable mechanical and optical performance.
5. Common fiber optic connectors
(1) FC fiber optic connector
This connector was first developed by Japan’s NTT. FC is the abbreviation of FERRULE CONNECTOR, indicating that its external reinforcement method is a metal sleeve, and the fastening method is a turnbuckle. The earliest, FC type connector, used the butt end of the ceramic pin. This type of connector is simple in structure, easy to operate, and easy to manufacture, but the fiber end is more sensitive to dust and prone to Fresnel reflection, making it difficult to improve return loss performance. Later, this type of connector was improved by adopting a contact pin (PC) with a spherical butt end surface, and the external structure remained unchanged, which greatly improved the insertion loss and return loss performance.
(2) SC type fiber optic connector
This is a fiber optic connector developed by NTT Corporation of Japan. Its shell is rectangular, and the structure dimensions of the pins and coupling sleeves used are exactly the same as those of the FC type. Among them, the end faces of the pins are mostly PC or APC-type grinding; the fastening method is the plug-in pin-bolt type, which does not need to be rotated. This type of connector is cheap, easy to plug and unplug, has small fluctuations in insertion loss, high compressive strength, and high installation density. ST and SC interfaces are two types of fiber optic connectors. For 10BASE-F connection, the connector is usually ST type, and for 100BASE-FX, the connector is mostly SC type. The core of the ST connector is exposed, and the core of the SC connector is inside the connector.
(3) Biconical connector (BICONICCONNECTOR)
The most representative product of this type of fiber optic connector was developed by Bell Laboratories in the United States. It consists of two precision-molded cylindrical plugs with truncated conical ends and a biconical plastic sleeve inside. The coupling assembly of the cylinder is composed.
(4) DIN47256 fiber optic connector
This is a connector developed in Germany. The structure dimensions of the pin and coupling sleeve used in this connector are the same as those of the FC type, and the end face treatment adopts PC grinding method. Compared with the FC type connector, its structure is more complicated, and there is a spring to control the pressure in the internal metal structure, which can avoid damage to the end face due to excessive insertion pressure. In addition, the mechanical precision of this connector is high, so the insertion loss value is small.
(5) MT-RJ type connector
MT-RJ started from the MT connector developed by NTT. It has the same latch mechanism as the RJ-45 LAN electrical connector. It is connected to the machine, and the optical fiber on the end face of the connector is designed as a double-core (0.75MM interval) arrangement. It is a next-generation high-density optical fiber connector mainly used for data transmission.
(6) LC type connector
LC type connector is researched and developed by the famous BELL (Bell) Research Institute, and it is made of the modular jack (RJ) latch mechanism which is easy to operate. The size of the pin and sleeve used in it is half of the size used by ordinary SC, FC, etc., which is 1.25MM. This can increase the density of optical fiber connectors in the optical fiber distribution frame. At present, in terms of single-mode SFF, LC-type connectors have actually occupied a dominant position, and their applications in multi-mode are also growing rapidly.
(7) MU type connector
MU (MINIATURE UNITCOUPLING) connector is the world’s smallest single-core optical fiber connector developed by NTT based on the most widely used SC-type connector. The connector adopts a 1.25MM diameter sleeve and a self-retaining mechanism, which has the advantage of being able to achieve high-density installation. Using MU’s L.25MM diameter ferrule, NTT has developed the MU connector series. They have receptacle type connectors for optical cable connection (MU-A series); backplane connectors with self-holding mechanism (MU-B series) and simplified receptacles for connecting LD/PD modules and plugs (MU-SR series) Wait. With the rapid development of optical fiber networks towards larger bandwidth and larger capacity and the wide application of DWDM technology, the demand for MU connectors will also increase rapidly.
6. The role of fiber optic adapter
Like fiber optic connectors, fiber optic adapters are also components that play a connecting role in fiber optic lines. The difference is that fiber optic connectors can only be used to connect optical cables of the same model or devices of the same model. Once two connected optical cables are encountered If it does not match the model of the device, it will be blinded. The fiber optic adapter is different. There are many different types of input ports and output ports on the box, and no matter what type of fiber optic line and equipment it is, it can be easily connected. The fiber optic adapter also has a function, which is to establish a signal branch. As mentioned above, there are several outlets on the fiber optic adapter box, and each outlet can establish a branch line.
Optical fiber adapters have a wide range of applications. First of all, they play an indispensable role in optical fiber communication networks. Our current network signals use optical fibers, so optical fibers have almost reached thousands of households. It is inseparable from the role of the fiber optic adapter. Then there is the cable TV network. Some TV signals are also transmitted by optical fiber. In such a cable TV network, a signal source such as a voltage-controlled oscillator is first used to generate an electrical signal, and then converted into an optical signal by a photoelectric element. It can be transmitted by optical fiber, and optical fiber adapters are also widely used in such an optical fiber TV signal network. In addition, optical fibers can also be used to build some local area networks for internal use in some units, and can also establish data connections between some electronic devices, which are also inseparable from optical fiber adapters. It can be seen that the role of the fiber optic adapter in the fiber optic communication network is the same as the role of the power connector in the circuit.
Seven, fiber optic adapter application range
- Optical fiber communication system
- Cable television network
- Local area network, optical area network
- Fiber to the home (FTTP)
- Video transmission
- Test equipment
