FOCI's custom designed couplers are ultra reliable devices featuring low backreflection, low insertion loss, and high port isolation over a wide range of temperatures and wavelengths. The Custom designed Couplers are designed to divide and/or combine different optical signals in optical fiber systems. With its innovative Fused Biconical Taper (FBT) process, FOCI's C-DD, C-DM, C-DS. C-DU, C-DW series Custom designed Couplers have proven to provide exceptional characteristics for all applications demanding critical performance. Splitting ration, input/output port number, operating wavelength, bandwidth, and all other requirements not included in other product data sheets can be customer specified to meet your needs. Available in a wide variety of packaging configurations, these C-DD, C-DM, C-DS. C-DU, C-DW series are used to denote dual window, multimode, unitary, wideband N x M couplers, with non-uniform coupling ratio. Various types of pigtailing and connector termination are available to meet your requirements.