A new method of optical fiber loss measurement by the side-illumination technique

A new method, "side-illumination method" for optical loss measurement is proposed and its applicability to graded-index multimode fibers is investigated experimentally. This method is non-destructive and the equipment for this measurement is very simple. The optical power coupling condition is examined and a comparison is made between the loss values obtained by the side illumination and the conventional cutback methods. In conclusion, the proposed method is found to provide highly accurate and reliable optical loss values.