The 2×2 1550nm Single Window Singlemode FBT Coupler Splitter With Steel Tube is a high-performance optical power-splitting and combining device designed for reliable operation in 1550 nm C-band singlemode fiber networks. Using advanced Fused Biconical Taper (FBT) technology, this 2×2 coupler splitter provides low insertion loss, high splitting accuracy, excellent wavelength stability, and stable bidirectional optical performance.