Optical receiver is instrument that convert light into electrical signals. Sometimes the fiber optic receiver is also called optical nodes. They contain a photo diode semiconductor, signal conditioning circuitry and an amplifier. Fiber optic receivers use three types of photo diodes: positive-negative (PN) junctions, positive-intrinsic-negative (PIN) photo diodes, and avalanche photo diodes (APD). The signal received by optical receivers are transmitted to RF network.