Amplitude control and test of optical sampling photonic analog to digital conversion system

The amplitude unstability of the 22 optical sampling time division multiplexing systems is investigated. The unstability comes from two aspects: insertion loss differences and various polarization states. Amplitude jitter results from the uneven insertion loss of each level and accumulates step by step. The system requires high insertion loss consistency. Various polarization states are caused by the path diversity. The sampling system can not function properly due to the polarization sensitivity of the electrooptical modulator. To solve the above problems, attenuators and polarization controller are applied to regulating and controlling the amplitude and polarization state of the pulse precisely. The performance is tested through analog signal sampling. The experimental result indicates that the effective number of bits is 2.35 bits.