Fiber optic canister having orthotropic, controlled thermal expansion bobbin

Abstract

A fiber optic canister includes a generally cylindrical bobbin and an optical fiber pack wound thereupon. The bobbin is formed at least in part from a material having orthotropic coefficient of expansion characteristics, arranged so that the coefficients of thermal expansion of the bobbin are matched to those of the overlying optical fiber pack. The optical fibers have a small longitudinal coefficient of thermal expansion and a larger transverse coefficient of thermal expansion. The orthotropic material of the bobbin is arranged so that the circumferential coefficient of thermal expansion of the bobbin is near zero, and the axial coefficient of thermal expansion is matched to that of the transverse coefficient of thermal expansion of the optical fiber pack. The bobbin therefore expands and contracts with changes in temperature at a rate approximating that of the overlying fiber pack. The orthotropic material of the bobbin is preferably a composite material of structural fibers in a matrix, with the structural fibers arranged in an off-axis manner to yield the required anisotropic thermal expansion behavior.

Dependencies are inferred from the claim text.