POLARIZATION PLANE MAINTAINING OPTICAL FIBER AND FABRICATING METHOD THEREFOR

摘要

Herein disclosed is an optical fiber having an intense ability to maintain the polarization plane, which is constructed of an optical waveguide having a circular core (1) and a circular cladding (2), a jacket (3) formed on the outer circumference of the optical waveguide which has an elliptical outer circumference, and a supporting portion (4) formed on the jacket.
In order to fabricate the above-specified optical fiber, a preformed rod is prepared by forming the jacket and the optical waveguide on the inner wall of a silica glass tube using materials which satisfy the relationship c2/a >/= 200/(100- gamma )-1, wherein: letter gamma stands for the ellipticity of the outer circumference of the jacket: letter c2 stands for the minor axis of the ellipse; and letter a stands for the radius of the circular optical waveguide. Then the silica glass tube is collapsed by heating while keeping its internal pressure lower than the atmospheric pressure by 1 to 20 mmH2O.