What are the welding methods for optical cables?

Update:19 Oct 2018

The methods mainly include permanent connection, emergency connection, and active connection.
1. permanent fiber connection (also known as hot melt):
This connection is to melt and join the joints of the two fibers by means of electrical discharge. Generally used in long-distance connection, permanent or semi-permanent fixed connection. Its main feature is that the connection attenuation is the lowest among all connection methods, with a typical value of 0.01~0.03dB/point. However, when connecting, special equipment (melting machine) and professional personnel are required to operate, and the connection point also needs special container protection.
2. Emergency connection (also called) cold melting:
The emergency connection is mainly to fix and bond the two fibers together by mechanical and chemical methods. The main feature of this method is that the connection is fast and reliable, and the typical attenuation of the connection is 0.1~0.3dB/point. However, the long-term use of the connection point will be unstable, and the attenuation will increase greatly, so it can only be used for emergency use in a short time.
3. Activity connection:
Active connections are a way to connect a site to a site or site to a fiber optic cable using a variety of fiber optic connectors (plugs and sockets). This method is flexible, simple, convenient, and reliable, and is often used in computer network wiring in buildings. Its typical attenuation is 1dB/connector.