Comparative Study of Direct Image Transmission through Various Optical Fibers Using the Phase-Conjugate Wave

In this article, we compare direct image transmissions through various multimode optical fibers, namely, step-index silica, graded-index silica, and step-index plastic fibers. We make use of a round-trip transmission in the optical fiber as well as a phase-conjugate wave generated by a self-pumped BaTiO3 crystal to recover a distorted image. The image was best recovered for a step-index silica fiber with a core diameter of 50 mm and NA 1⁄4 0:18 among three types of 1-m-long silica fibers. Stepindex silica and plastic fibers with a length of 1m could transmit an optical image up to a spatial resolution of 20 line pairs/ mm. We successfully recovered a distorted image even after transmission over a 35.5-m-long step-index silica fiber. It is revealed that NA as well as core diameter is an important factor for increasing the image quality in direct image transmission. [DOI: 10.1143/JJAP.46.5172]