An integrated circuit that reduces back reflection of an optical signal is described. This integrated circuit may convey an optical signal in an optical waveguide defined in a layer in the integrated circuit. The integrated circuit may split the optical signal into portions of the optical signal using an optical splitter, and may convey the portions of the optical signal in at least two arms of the optical waveguide. Then, the integrated circuit may establish a predefined phase offset between the portions of the optical signal using at least a phase-offset device in one of the two arms. Furthermore, the integrated circuit may optically couple the portions of the optical signal at optical coupling interfaces at ends of the two arms. Note that the predefined phase offset may reduce the back reflection of the optical signal at the optical splitter to less than a threshold value.