DNC 1:2 HD (Heavy Duty) fiber couplers are Single Mode coupler with an even split ratio from one input fiber to multiple output fibers. 1:2 HD couplers are available with 1.8mm loose tube single mode fiber and terminated or unterminated as per customer needs. Un-connectorised 1:2 HD fiber couplers come with no connectors for easy splicing or connectorization. Connectorized 1:2 HD fiber couplers are available with your choice of Fiber Optic Connectors: LC, SC, FC, and ST. A fused fiber optic coupler is a structure formed by two fibers. The two fibers are placed side to side, twisted, put in a flame, heated up, and then drawn longer and become fused together. There is light power exchange between the fibers.