All has the function of photo detectors convert light into electrical current has to be polarized to reverse form. Regardless of the type of fiber PIN detectors generally operate in the area between 850 to 1310 µm. advantages: more robust that the APL detectors, technology and application less costly, less semiconductor material, useful life greater than other detectors. Disadvantages: power to low power signals detection unless the APD detectors, response time is smaller than the other detectors, the signal-to-noise ratio detriment this type of detector. APD-“Avalanche Phodiode”: The APD Photodetectors are Photodetectors that combine optical signal detection with amplification (gain) of the photocurrent. Its main advantage is a high signal-to-noise ratio, especially at high bit rates. The photo-detector PIN is enough for your project primarily, has best features as linearity, lifetime, response time and the circuits of polarizations are simpler.