<title>Compensation for the effect of incident-light-polarizing state in OCT</title>

Abstract

Optical current sensing has manifold advantages over the conventional device. It is of great benefit to develop optical current transducer. Due to the inherent birefringence of optical fiber, fiber-optic current transducer has lower sensitivity than bulk glass optical current transducer. Therefore, in research the bulk glass OCT is preferred to fiber optic current transducer. Because multimode optical fiber has larger core diameter and aperture diameter, the couple coefficient of light source to multimode optical fiber is much larger than that to the single mode optical fiber. So multimode optical fiber is adopted as the medium to carry the optical signal in bulk glass OCT. However, the polarization state of optical signal will change randomly because a multimode optical fiber is not polarization-maintaining. As a result, the intensity of the optical signal will change randomly. The sensitivity of the transducer will be suffered. And it makes the design of electrical equipment difficult. A way to solute this problem is discussed. And an inventive optical current configuration is described. Incident light is divided into two orthogonal polarized component through splitters. After a serial of processing, as dephasing etc, the intensity of output light can be proved to be independent on the polarization state of the incident light. Thus, the random variation of the intensity of the optical signa is eliminated theoretically.