光载无线系统中的线性化技术

[摘要] 文章认为在常规的光载无线系统中电光调制器的固有非线性特性一直是限制该类系统动态范围的重要因素之一，为了实现更高的动态范围，以满足系统对于线性度的需求，需要抑制电光调制器的非线性所带来的交调失真。文章对光载无线系统的非线性过程进行了深入研究，从调制器的结构以及与调制器独立的后补偿两个方面提出光载波相位偏移技术和光边带处理技术，灵活有效地提高了微波段光载无线系统甚至毫米波段光载无线系统的无杂散动态范围20 dB以上。

[关键词] 光载无线系统；马赫-曾德尔调制器；双平行调制器；非线性补偿

[Abstract] In a traditional radio-over-fiber (ROF) system, the nonlinear transfer function of a Mach-Zehnder modulator limits the spuriousfree dynamic range (SFDR). For improved dynamic range, intermodulation distortion that is generated by the nonlinearity of the modulator must be eliminated. In this paper, we theoretically and experimentally investigate nonlinearity in the ROF system. With optical carrier phase shift and optical sideband processing, the SFDR of the microwave/millimeter-wave radio-over-fiber system can be improved more than 20 dB.

[Keywords] radio-over-fiber; Mach-Zehnder modulator; dual-parallel modulator; nonlinearity compensation