A study of the polarization properties of AT&T's rectangular polarization-maintaining fiber.

An experimental study of the polarization properties of AT&T's rectangular polarization-maintaining fiber is reported. The extinction ratio is measured at 1320 nm for lengths of 20m, 40m, 100m, 310m, and 804m. The first demonstration that the length dependence of the extinction ratio of a polarization- maintaining fiber obeys random coupling theory is also reported; this is due to the rectangular geometry of the fiber which facilitates winding and packaging the fiber with no perturbations. The polarization-holding parameter is 2.08 +-0.09 x 10 sup -6 m sup -1. The state of polarization as a function of the input angle of the linear polarized field is determined for various lengths. For lengths >=100m, depolarization effects eliminate all other states of polarization except the linear on-axis polarization state. For shorter lengths, other polarization states can propagate in the fiber; however, if the input angle of the field is within 5 degrees of the polarization axis of the fiber only the linear on-axis polarization state will propagate in the fiber. Using an elasto-optic point perturbation technique, a beat length of 6.78 +- 0.36 mm was measured directly at a wavelength of 1320 nm, inferring a phase index difference of 1.95 x 10 sup -4.