When using a multimode fiber lead in an optical current measurement system, the optical power in the guided modes is often determined by the coupling conditions at the input end of the fiber. If only the skew rays are excited in the fiber lead—under appropriate coupling conditions—the vibration‐induced noise normally experienced in the fiber lead in such an optical current measurement system can be effectively suppressed, especially when a low coherence source and a long length of multimode fiber is used. The experimental conditions for this are considered and discussed in this article. ©1996 American Institute of Physics.