In-line single-mode fiber polarization controllers at 1.55, 1.30, and 0.63 Mum.

Single-mode fiber-optic quarterwave plates utilizing linear birefringence induced by coiling the fiber in a loop are described. Optimal quarterwave plates are obtained by one turn of 1.0-cm radius for 0.6328-μm light for a single-mode fiber with an outer diameter of 81 μm. For single-mode fiber with a diameter of 120 μm, optimal quarterwave plates consist of one turn of 0.95-cm radius for 1.30-μm wavelength or two turns of 1.3-cm radius for 1.55-μm wavelength. Devices were made for cabled and uncabled fiber which provide complete polarization control by adjusting the angles of two such coils.