The 2×2 1310 & 1490nm Dual Window Singlemode FBT Coupler Splitter With Steel Tube is a high-performance optical splitting and combining device designed for stable operation across the 1310 nm (O-band) and 1490 nm (E-band) wavelength windows. Manufactured using advanced Fused Biconical Taper (FBT) technology, this coupler splitter offers low insertion loss, precise splitting ratios, excellent wavelength stability, and consistent bidirectional optical performance for dual-wavelength singlemode fiber networks.