Design for a single‐mode optical fiber switch

Abstract

AbstractBecause of its low loss and broadband characteristics, the optical communication system with single‐mode fibers is promising for long‐distance large‐capacity communication and subscriber video transmission systems. These systems require optical switching techniques for upgrading and for expanding applications. In this paper, with a view to establishing a method for design of a single‐mode optical fiber switch, an optical collimating system employing a focusing rod lens is analyzed by means of a beam mode expansion method. Next, the characteristics of the optical collimating system, the characteristics of a large matrix optical switch collimating system and the displacement, which is important in the optical circuit, are discussed. Finally, a method of construction and test results are described for a 1 × 3 single‐mode fiber optical switch employing a parallelogram prism. A single‐mode optical fiber switch with insertion loss of 0.4 dB and switching reproducibility of less than 0.1 dB is realized. The results confirm the validity of the design method of single‐mode optical fibers.