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This synchronous quadrature-phase-shift keying (QPSK) receiver concept allows us to process signals in parallel after electronic demultiplexing. An automatic electronic polarization control with a control time constant in the low microsecond range is provided. It is followed by a phase-locked loop free carrier recovery. An intermediate frequency linewidth tolerance of up to 10-3 times the QPSK symbol rate is expected. Commercially available distributed feedback lasers shall, therefore, suffice.