Fiber optic couplers are optical devices that connect three or more fiber ends, dividing one input between two or more outputs, or combining two or more inputs into one output. The cable type accepted by fiber optical couplers can be single mode or multi mode. Choices for coupler type include single window, dual window, or wide band. Single window optic coupler is designed for a single wavelength with a narrow wavelength window. Dual wavelength optical couplers are designed for two wavelengths with a wide wavelength window for each. Wide band optical coupler is designed for a single wavelength with a wider wavelength window. Wavelength choices for fiber optic couplers include 850nm, 1310nm and 1550nm.