title: Laser-phase-fluctuation-insensitive offset-frequency-spaced two-tone optical coherent detection scheme and its transmission for radio-over-fiber systems.
abstract: We propose a new optical coherent detection scheme with a "two-tone" local light, which is also in principle insensitive to the laser phase fluctuation and is assisted by the digital signal processing technique for radio-over-fiber (RoF) systems. The main feature of our proposal is that the frequency separation of the two-tone local light is different from that of the RoF signal, which is called "offset-frequency-spaced" in this paper. First, we explain the principle of our new proposal and experimentally demonstrate the data recovery. Then, the influence of the frequency detuning between photo-detected modulated and unmodulated signals is discussed. Moreover, the transmission performance with an error vector magnitude (EVM) is evaluated for the optical coherent detection of a 10-Gbaud quadrature-phase-shift-keying RoF signal after a 20-km-long standard single-mode fiber transmission.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kuri
authors.forename: Takahide
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kawanishi