CONSTANT POLARIZATION OPTICAL FIBER COUPLER AND CONSTANT POLARIZATION OPTICAL FIBER

摘要

PURPOSE:To provide the constant polarization optical fiber coupler having high performance with high productivity by heating and stretching a part of the constant polarization optical fiber having two cores, =2 stress imparting parts and a clad enclosing the same to form a stretched part and connecting optical fibers for waveguiding to the respective cores at both ends of the constant polarization optical fiber. CONSTITUTION:The constant polarization optical fiber coupler 11 is constituted by forming the stretched part to a part of the constant polarization optical fiber 15 of the double cores having the two cores 12, the two stress imparting parts 13 and the clad 14 enclosing the same. The coupler is constituted by connecting two pieces of optical fibers 17 for waveguiding respectively to both ends of the fiber 15 of the double cores. The possibility that the relative dispositions of the cores and the stress imparting parts in the stretched part are deformed is, therefore, drastically decreased as compared with the coupler obtd. by fusing and stretching two pieces of single-core constant polarization optical fibers. The cancellation of stresses is hardly generated in this way and the high-performance coupler having a high extinction ratio is obtd. The production of the high-performance coupler at a high yield is thus possible.