Fiber Joints

Fiber joints are the points where two optical fibers are permanently connected to create an uninterrupted transmission path. These connections are essential in fiber optic networks, enabling the extension, branching, or repair of fiber cables while ensuring minimal signal loss during transmission.

What Are Fiber Joints

Background

The development of fiber optic connectors was driven by the need to address the challenge of connecting optical fibers in communication systems. In fiber optic communication, the length of a single fiber is often insufficient for long-distance transmission, so multiple fibers need to be joined together to create a complete communication link.

Working Principle

The operation of a fiber optic connector is based on the principle of total internal reflection. When light passes from one medium into another, if the angle of incidence is greater than the critical angle, the light undergoes total reflection. In a fiber optic connector, light is transmitted from one fiber to another by precisely aligning the fibers, allowing light to pass with minimal loss between the two fibers.

Key Performance Parameters

The main performance indicators for fiber optic connectors are insertion loss and return loss. Insertion loss refers to the reduction in signal strength when the fibers are connected, usually measured in decibels (dB). Return loss is the signal loss caused by reflections from imperfections in the connector, which result in part of the light being reflected back into the original fiber, also measured in decibels (dB).

Applications

Fiber optic connectors are widely used in various fiber optic communication systems, including long-distance transmission lines, distributed networks, and fiber access networks. They are also used in other fields such as fiber optic sensors and fiber laser systems.

Types of Joints in Optical Fiber

Splice

A splice is a joint that is either permanent or semi-permanent and can typically be used only once. There are two main types of splices:

• Mechanical Splice: This type of splice holds the two fiber ends together mechanically, acting as an alignment tool that allows light to pass from one fiber to the other.

• Fusion Splice: This process involves fusing two fiber ends using an electric arc. A monochromatic light is passed through one fiber (the input), and the second fiber is adjusted to maximize the output signal. Once aligned, a high-voltage electric arc is applied to fuse the fibers together.

Connector

Connectors are used at the ends of fiber optic cables when they are terminated. Since the advent of fiber optic technology, various connector types, including SC, FC, and LC, have been developed. For more in-depth details, refer to the Fiber Optic Connector Tutorial.

• DNP Connector: Dry No Polish connectors are pre-assembled and do not require field polishing or assembly. It is suitable for on-site installation and emergency repair, and is typically used in rapid deployment situations such as Fiber to the Home (FTTH) or Fiber Access Networks. FS offers a wide range of pre-polished connectors to maximize your convenience.

Coupler

A coupler is a device used for multiplexing and de-multiplexing signals. When used for de-multiplexing, it is referred to as a Combiner. Various types of couplers include:

• T-Coupler: This coupler splits one incoming signal into two outputs using a grin lens and beam splitter.

• Star Coupler: A star coupler splits one incoming signal into multiple output signals.

• Three-Port Coupler: This coupler divides one input signal into two outputs without the need for a grin lens or beam splitter.

Check our blog to learn more about FS Coupler.

Differences Between Splice, Connectors and Coupler