| 摘要 |
PURPOSE:To provide a low loss and good resistance to radiation by specifying the respective refractive indices of a core, clad and elliptical jacket and the size in the prescribed part at specific values and forming the clad of silica glass contg. fluorine, P2O5 and B2O3. CONSTITUTION:An optical fiber for maintaining plane of polarization has the relation expressed by the inequality I where the respective refractive indices of a core 21, a clad 22 and an elliptical jacket 23 are designated as n1, n2, n3 and has the relation expressed by the inequality II where the radius of the core is designated as T, the thickness of the clad as delta1T, and the total min. thickness of the clad and the elliptical jacket as delta2T. Such relations are obtd. by forming the core 21 and the support 24 of high purity silica, making the clad 22 into the constitution consisting essentially of SiO2 and contg. fluorine, P2O5 and B2O3 and making the jacket 23 into the constitution consisting essentially of SiO2 and contg. P2O5 and B2O3. A low loss and good resistance to radiation are thus obtd. |
