Fibre Optic Splitter Introduction
Fibre optic splitter is a device that split the fibre optic light into several parts by a certain ratio. For example, when a beam of fibre optic light transmitted from a 1X4 equal ratio splitter, it will be divided into 4-fibre optic light by equal ratio that is each beam is 25% of the original one. Fibre optic splitter is different from WDM. WDM can divide the different wavelength fibre optic light into different channels. Fibre optic splitter divide the light power and send it to different channels.

Single window and dual window
Here the window refers to the working wavelength. Single window fibre optic splitter is with one working wavelength, dual window fibre optic splitter is with two working wavelength. For multimode fibre, the term means that the fiber is optimized for 850 nm and 1310 nm operation. For single-mode fibers, the term means that the fiber is optimized for 1310 nm and 1550 nm operation. For single window fibre optic splitter, its working wavelength usually is one of the above said wavelength.