The 2×2 1310 & 1550nm Dual Window Singlemode FBT Coupler Splitter With Steel Tube is a high-performance optical splitting and combining device engineered for reliable operation across both 1310 nm (O-band) and 1550 nm (C-band) wavelength windows. Utilizing advanced Fused Biconical Taper (FBT) technology, this splitter delivers low insertion loss, precise coupling ratios, excellent wavelength stability, and consistent bidirectional optical performance in dual-wavelength singlemode fiber networks.