ABSTRACT

A linearization scheme for the microwave photonic link based on dual-parallel Mach–Zehnder modulator is proposed, which can suppress the third-order intermodulation distortion (IMD3) introduced by the nonlinearity of the electrooptical modulator and thus improve the spurious-free dynamic range (SFDR). By adjusting the optical power splitter, phase shifter, one of the three main factors that produce IMD3 can superimpose destructively with the other two. Theoretical analysis and simulation results show that our proposed scheme has a better electrical signal-to-interference ratio of 24.9 dB than the conventional scheme, and thus the SFDR has a 9 dB·Hz^2/3 improvement. In addition, in the back-to-back system, the error vector magnitude of a 250-MSym/s 16-quadrature-amplitude-modulation is reduced to 2.98% in our proposed scheme compared with the conventional scheme of 14.17%.

摘要

提出了一种基于双并联Mach-Zehnder调制器的微波光子链路线性化方案，可以抑制电光调制器非线性引入的三阶互调失真（IMD3），从而提高无杂散动态范围（ SFDR）。通过调整光功率分配器、移相器，产生IMD3的三个主要因素之一可以与其他两个发生破坏性叠加。理论分析和仿真结果表明，我们提出的方案比传统方案具有更好的24.9 dB电信干比，因此SFDR具有9 dB·Hz ^2/3改进。此外，在背靠背系统中，与传统方案的 14.17% 相比，我们提出的方案中 250-MSym/s 16 正交幅度调制的误差矢量幅度降低到 2.98%。