Comparing with electronic beam forming, integrated optical beam forming is very promising for optical controlled phase array system, because much broader band beam steering can be achieved without the beam squint effect. The single channel optical true time delay lines based on the cascade microring resonators and switched optical delay waveguides have been extensively investigated. The optical beam forming chip based on multi-channel microring resonators have also been demonstrated, however only limited working bandwidth were obtained due to their inherent tradeoff between the delay and bandwidth. The bandwidth limitation can be overcome by using integrated optical beam forming chip composed of switched optical delay waveguides, which has not been demonstrated and evaluated. Here, a 1$\times$4 optical beamforming chip with four integrated switchable delay lines units designed to control the Ka-band phased antenna arrays is proposed and demonstrated experimentally. The maximum delay of 96 ps with a delay increment about 3.02 ps/stage was obtained, which is in accordance with the design well. Based on the measured delay times, the directional diagrams of the optical beamforming network were simulated and beam angle coverage of 90° can be achieved. Furthermore, a magnitude response experiment was carried out to evaluate the performance of the optical beam forming chip, and a remarkable working bandwidth of 29 GHz was achieved.

与电子束形成相比，集成光束形成对于光控相控阵系统非常有前途，因为可以实现更宽频带的束转向，而无需束斜视效果。基于级联微环谐振器和开关光延迟波导的单通道光学真实时间延迟线已得到广泛研究。还已经证明了基于多通道微环谐振器的光束形成芯片，但是由于延迟和带宽之间的固有折衷，只能获得有限的工作带宽。通过使用由开关光延迟波导组成的集成光束形成芯片可以克服带宽限制，这尚未得到证实和评估。在这里1$\times$提出并通过实验证明了具有四个集成的可切换延迟线单元的4光束成形芯片，这些单元设计用于控制Ka波段相控天线阵列。获得的最大延迟为96 ps，延迟增量约为3.02 ps /级，这与设计井相符。根据测得的延迟时间，模拟了光束形成网络的方向图，可以实现90°的光束角覆盖。此外，进行了幅度响应实验以评估光束形成芯片的性能，并获得了29 GHz的显着工作带宽。