title: I/Q intensity-demodulation analog photonic link based on polarization modulator.
abstract: We experimentally investigate a high-linearity analog photonic link based on polarization-modulation in-phase/quadrature (I/Q) intensity-demodulation. In the proposed system, a light wave with its polarization direction oriented at an angle of 45° with respect to the principal axis of the polarization modulator (PolM) is polarization modulated by a drive signal. In the receiver, the polarization-modulated signal is split into two paths using a 50:50 optical coupler (OC). In each path, a polarization beam splitter (PBS) is connected to the PolM via a polarization controller (PC) to realize the in-phase and quadrature signal, respectively. Thanks to the polarization-modulation to intensity-modulation conversion, the fluctuation of the optical phase noise has no impact on the coherent signals. In addition, the use of a single PolM allows the link avoids the matching requirements of dual modulator schemes. The linearization leads to suppression of the third-order intermodulation (IMD3) by more than 40 dB, compared to the quadrature signal. Experimental results show that the link gain is -11.5 dB, noise figure is 26.5 dB, and the third-order limited spurious free dynamic range (SFDR) is 124 dB in a 1 Hz bandwidth.
authors.affiliation: State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing, 100876, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Lv
authors.forename: Kun
authors.initials: K
authors.lastname: Xu
authors.forename: Yitang
authors.initials: Y
authors.lastname: Dai
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Wu
authors.forename: Jintong
authors.initials: J
authors.lastname: Lin