The 1×2 1310 & 1490nm Dual Window Singlemode FBT Coupler Splitter With ABS Box is a high-quality optical power-splitting device designed for stable and accurate performance across the 1310 nm (O-band) and 1490 nm (E-band) wavelength windows. Using advanced Fused Biconical Taper (FBT) technology, this splitter provides low insertion loss, precise coupling ratios, excellent wavelength stability, and long-term reliability for dual-wavelength fiber-optic communication systems.