基于LiNbO3晶体的双折射和电光效应设计制作了一种2×4的90°相移自由空间光学桥接器。该桥接器利用晶体的双折射效应进行信号光和本振光的分光/耦合，电光效应引入相位调制，在给定电场条件下实现2×4 90°空间光学桥接器的功能。对空间光学桥接器进行了实验测量和分析。实验结果表明该桥接器性能良好，相位连续可调，相位误差可通过电压调制补偿，应用于相干接收系统。

A free-space 2×4 90° optical hybrid with electro-optic modulation is designed and fabricated based on the birefringence effect and electro-optic effect of LiNbO3 crystal. It splits and recombines a signal beam and a local oscillator beam by birefringence effect, and the desired phase shift is introduced by electro-optic effect. It realizes the appropriate function of a 2×4 90° optical hybrid under given electric-field conditions. The performance of 2×4 90° optical hybrid is measured experimentally and analyzed. Experimental results show that the optical hybrid has good performance of phase modulation and the proposed 90°optical hybrid. Its phase shift output is tuned electrooptically and phase errors can be compensated by adjusting the applied electric field. It has potential applications in coherent receivers.