Polarization beam splitters and 3 dB couplers are used to construct a home-made 90° optical hybrid,by which a polarization diversity optical coherent receiver is carried out with single-ended detection. A 10 Gb/s polarization multiplexed differential phase shift keying (DPSK) signal is transmitted through 280 km standard single-mode fiber (SSMF) using erbium-doped fiber amplifier (EDFA) amplification,and no error bits are measured in the result. The various digital signal processing algorithms in coherent detection are discussed. Carrier phase estimation,optical chromatic dispersion compensation and digital polarization demultiplexing are carried out. The phase error offset from the 90° of the optical hybrid is compensated by using statistical method. The algorithm is irrelevant with signal modulation format and fiber chromatic dispersion. Digital polarization demultiplexing is carried out by using constant modulus algorithm,and the convergence time of the algorithm is less than 0.5 μs