In current quadrature phase shift keying (QPSK) systems for coherent optical communications, there are two algorithms based on complex operation and angle operation to recover carrier phase. This paper analyzed and compared the recovery performance and implementation complexity of the Viterbi-Viterbi phase estimation (VVPE) algorithm based on complex operation and the barycenter phase estimation (BCPE) algorithm based on angle operation. The simulation proves that the VVPE algorithm is stronger in resisting additive noise than the BCPE algorithm and has a lower probability of cycle slip. The performances of the two algorithms are close when there is no cycle slip. In this paper, we carried out QPSK coherent reception experiments with rates of 2.5 GBaud (the product of symbol rate and linewidth is 4×10 ^-5) and 10 GBaud (the product of symbol rate and linewidth is 1×10 ^-5). Then, we evaluated the performance of the two algorithms using the offline Matlab and Verilog methods. For the 2.5 GBaud QPSK signal, after the length of the average filter is optimized, the receiving sensitivity of the two algorithms is -52 dBm@1×10 ^-3, and when the cycle slip occurs, the receiving power of the VVPE algorithm and BCPE algorithm is -54 dBm and -53 dBm, respectively. For the 10 GBaud QPSK signal, after the length of the average filter is optimized, the receiving sensitivity of the two algorithms is -47 dBm@1×10 ^-3, and in the case of cycle slip, the receiving power of the BCPE algorithm is -52 dBm. Relying on Xilinx Virtex Ultrascale+ FPGA, this paper compared the two algorithms with 10 GBaud system rate and 64 parallel channels. Regarding 8-bit and 16-bit input signals respectively for the VVPE algorithm and BCPE algorithm, the receiving sensitivity is -51 dBm@2×10 ^-2. The occupancy of the hardware look-up table of the BCPE algorithm is about 5.78% lower than that of the VVPE algorithm.