The optical polarization properties of glase single mode optical fiber, which is manufactured elsewhere by drawing a preform prepared by C.V.D. method, is investigated. A sample fiber of which core dopants are $P_2O_5$ and $G_eO_2$ shows linear phase retardation of 46 deg/cm, and the birefringence of another sample which core dopant is only $G_eO_2$ is negligible for the fiber length of 200 cm.
When the fiber of negligible birefringence is under lateral compression stress by brass weights, stress-induced phase retardation is found to be $\delta_c$=46 deg/N, and that with primary coating $\delta_c$=19 deg/N. Bend-induced phase retardation is found to be $\delta_b=\frac{28}{R^2}$ deg/cm, where R is the radius (in cm) of bending circle.
When the fiber is twisted optical activity appears in the fiber at the rate of 0.076 times the twist angle. And longitudinal tension stress does not affect the optical polarization properties of the fiber.
The birefringences are calculated from stress-optical basis and it is found that agreements with the experimental results are satisfactory.
