Polarization retaining fiber

• Main Authors: DOUD PAUL D, GILLILAND JOHN W, CHRISTOFF WILLIAM R
• Format: Patent
• Language: English
• Published: 23.05.2002
• Edition: 7
• Subjects: CHEMISTRY; GLASS; MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES; METALLURGY; MINERAL OR SLAG WOOL; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

PURPOSE: To form a polarization maintaining optical fiber which is long-sized and improves remarkably a polarization characteristic by forming a core of a circular or elliptical shape and forming a refractive index distribution of said core into a graded type shape. CONSTITUTION: Holes 3'a, 3'b for, stressing base materials are opened to a quartz bar 5 having 50 mm diameter and 150 mm length in the positions symmetrical with the center of the quartz bar and a hole 4' for a core base material is opened at the center of the bar 5, by means of an ultrasonic drill, then stressing base materials 3a, 3b and a fiber core base material 4 are inserted into these holes. The stressing base materials consist of SiO2 glass doped with 10.5 mol % B2O3 and 4.5 mol % GeO2. The core base material is doped with 16 wt % GeO2, has a refractive index distribution of a square function roughly in the radial direction. Said material has a ratio of five between the diameter of the clad and the diameter of the core. After the material 4 and the members 3a, 3b are mounted to the bar 5, the bar is drawn under the pressure reduced to about 10 & sim; 100 Torr. The resulted polarization maintaining optical fiber is improved in crosstalk, i.e., the fiber having the core of a graded type refractive index distribution