The light signal reception (usually includes light detector, optical amplifiers, equalizer and signal processing process) equipment.

In optical fiber communication system, optical receiver task with minimal additional noise and distortion, recovering the optical fiber transmission by optical carrier carries information, so the light output characteristic comprehensive reflection of the receiver the optical fiber communication system performance. Light the light signal transmitter launch by the transmission, not only the amplitude attenuation, and pulse waveform also stretcher, optical receiver the function of the one is testing after a weak light signal transmission, and enlarged, shaped into the original signal transmission, regeneration.

1. The photoelectric detector: it is the main purpose of using photoelectric effect for the light signal into electrical signal. In optical communication system, the requirements of the photoelectric detector is high sensitivity, fast response, low noise, low cost and high reliability. Photoelectric detection process is the basic principle of light absorption. At present, in the optical communication system of photoelectric detector is used in PIN photoelectric diode and avalanche diodes (APD). Two kinds of detector performance comparison: because the same performance compared with the PIN APD, PIN of the cost, and the noise of the PIN to low.

2. Optical receiving system: in the receiver, receiving antenna is the role of the spread of space optical field collection and meet to probe the surface.

3. Signal processing

Space optical communication system, optical receiver receive the signal is very weak, and together with high in background noise interference of field, can lead to the receiver SNR S/N < 1. So to signal processing is very necessary. Usually the measures taken are: one is in optical channel, the light narrowband filter to receive the light signal processing, to suppress the interference of background stray light. Optical filter absorbing the basic types of filters, interference filters, birefringence filters and new type of atom resonance filters, etc. . Second, in the telecom road, the preamplifier will produce photoelectric detector in the dim light born current signal into voltage signal, again through the main amplifier to signal for further amplification. Then the equilibrium and filtering methods, such as plastic and processing signal, the last through the clock extraction, judgment circuit and decoding circuit, recovery of the send information.