Patent ID: 8873953

Claim:
A method for multi-symbol polarization switching for differential detection optical systems, comprising the steps of: modulating output light of a laser source by a DQPSK modulator; splitting a stream of data comprising de-multiplexing the stream of data into multiple parallel low-speed data blocks; manipulating the low-speed data blocks comprising: encoding the bits in each low-speed data block using DQPSK differential precoders; and multiplexing to combine four in-phase and four quadrature inputs, I and Q, respectively, to thereby generate multi-symbol DQPSK differential encoded signals, and wherein each multi-symbol comprises four bits; driving the DQPSK modulator with the multi-symbol DQPSK differential encoded signals to generate optical multi-symbol DQPSK differential-encoded signals, polarizing said optical multi-symbol DQPSK differential-encoded signals with a polarizing modulator to generate optical multi-symbol polarization-switched DQPSK signals, wherein the modulation speed of the polarizing modulator determines how often polarization states vary; and recovering correct original data by a receiver using differential detection.