High-data rate differential phase shift keying receiver for satellite-to-ground optical communication link

Abstract

The high data-rate satellite-to-ground coherent optical communication link is limited because the phase front of a beam is impaired when passing through the atmospheric turbulence. Based on the interference of two successive data bits in an unequal arm-length Mach-Zehnder delay interferometer, a differential phase shift keying receiver is designed for high data-rate satellite-to-ground coherent optical communication links due to its immunity of the wave front impairment when passing through the atmospheric turbulence. In the time-delay self-homodyne interferometric detection used in 2×4 90 degree optical hybrid, the optical path difference corresponds to the duration of one bit. The optical path difference is stabilized to below one thousandth of the wavelength by moving a finely motorized platform with the close-loop control using the phase feedback from the outputs of the 90 degree hybrid. The 2.5 Gbps optical communication link has already been verified between two buildings over a distance of 2.4km in the worse-case atmospheric conditions. The design and experimental results are given in this paper.Keywords: differential phase shift keying receiver, coherent optical communication link, self-homodyne interferometric detection, 2×4 90 degree optical hybrid, balanced receiver, direct detection DPSK, Mach-Zehnder interferometer, Michelson interferometer

Performance analysis of pupil-matching optical differential receivers in space-to-ground laser communication

“…With the use of DPSK modulation in a space-to-ground laser, both temporal and spatial phase errors are eliminated by pupil-matching differential interference. Relevant theoretical analysis and experimental validation to overcome atmosphere turbulence have also been reported [12,13]. However, this receiving system sets a high-level requirement for machining precision of lens groups.…”

2.5- and 5-Gbps time-delay self-homodyne interference differential phase-shift keying optical receiver for space-to-ground communication link

“…27 The unequal-arm-length MZI-based coherent DPSK receiver has also been proposed. 28,29 In this paper, the 2.5-and 5-Gbps pupil-matching time-delayed self-homodyne interference DPSK optical receivers based on the free-space unequal-arm-length MZI and 2 × 4 90-deg optical hybrid 30 for space-to-ground optical communication link are designed and verified between two buildings in the downtown are over a distance of 2.4 km in the worst-case atmospheric conditions.…”