Optical Splitters
An optical splitter takes light from one fiber and splits it into two or more light streams. They are used in FTTH systems if you decide to go with a GPON architecture (see the Optical Line Terminal page for an overview of GPON vs Point to Point). Splitters used in a GPON system are passive (meaning they aren't powered), and bi-directional, allowing light to travel in both directions. Splitters come in 1-2, 1-4, 1-8, 1-16 and 1-32 versions. They typically have connectors on the fanout side.
You use splitters in the field to allow you to share a single backbone fiber among up to 32 houses. You would rarely use a 1-32 splitter (maybe in a multiple unit building), and instead cascade the splitters as you went along. Field splitters are housed in the splice closures or near them in the vault/pedestals.
If you are using a central office split, then you can house the splitters anywhere convenient, but be aware that there are companies that have patch panels with space for integrated splitters. Splitters are not used for point to point architectures.