Study on Side-polished Plastic Optical Fiber used as Line Source

A side-polished plastic optical fiber is proposed as the line source of a linear fiber array in a liquid level sensor. We hope the leakage light power of side-polished plastic optical fiber along the axial direction is constant. To that end, the transmission characteristics of the line source is investigated, and a formula describing the relationship between the polished depth and the side leak light power is developed with a simple method. A 300 mm long gradient side-polished plastic optical fiber is fabricated according to the theoretical conclusion, its side-leak light power is measured and the measurement results are discussed.