Why is 850 nm and 1310 nm used in optical fiber though 1550 nm has minimum attenuation per kilometer? - Quora
Amazon.com: 5 Pack LC to LC Duplex Single Mode Adapter, LC/UPC Fiber Optic Coupler for Single Mode (SM) Fiber Cable or Connector, 1310~1550 nm, Internal Shutter plates, Green : Electronics
532 nm Single Mode Fused Fiber Optic Couplers / Taps