Fiber optic connectors are passive devices that enable detachable connections between optical fibers and connect the two end faces of optical fibers.
Under normal circumstances, fiber optic connectors can be plugged and unplugged more than 1000 times, have a long service life, and generally have a tensile strength of not less than 90N. They can also be used in the temperature range of -40 ℃ to+70 ℃, and have good performance.

  At present, silicon-based and plastic materials are common propagation media for fiber optic connectors, and common types of connectors include FC, SC, LC, and so on.

  Among the common models mentioned above, the FC type connector was first developed by NTT Corporation in Japan. Its external reinforcement method is to use a metal sleeve, and the fastening method is a screw buckle, with high tensile strength. FC connectors can be used for single-mode or multi-mode optical fibers, with a simple structure, easy operation, and easy production. However, their fiber ends are sensitive to dust and prone to Fresnel reflection, resulting in high return loss.
  The SC type fiber optic connector is developed by NTT Corporation in Japan. Its housing is made of molded glass fiber plastic and has a rectangular shape. The structural dimensions of the pins and coupling sleeves used are exactly the same as those of the FC type. Due to its use of plug-in bolt fastening, there is no need for rotation, making it easy to plug and unplug, cost-effective, with minimal fluctuations in insertion loss, high compressive strength, and high installation density.
  The LC type connector was first developed by the renowned American laboratory Bell. It is made using a modular jack (RJ) latch mechanism, making it easy to operate. The size of the pins and sleeves used is only 1.25mm, which is half of the size of ordinary SC, FC, etc.      Therefore, it can improve the density of optical fiber connectors in fiber optic distribution frames. At present, LC type connectors have actually taken the dominant position in single-mode SFF, and their applications in multi-mode are also rapidly growing.
  In addition, according to the different shapes and grinding degrees of the end faces of fiber optic connectors, they can be divided into: PC (tight contact) type, SPC (super tight contact) type, UPC (extremely tight contact) type, and APC (angled physical contact) type. Their return losses, that is, the decibel ratio of the backward reflected light (scattered light continuously transmitted to the input end) to the input light at the fiber optic connection, are -35dB and -40dB, respectively; －55dB；－65 dB。
  As the return loss decreases, the impact of reflected light on the light source and system also decreases. Therefore, among the above four, APC has the best performance and PC has the worst performance.