Abstract: The invention relates to optical systems comprising thin film optical waveguide isolators that are characterized by linear birefringence at least some wavelengths and temperatures. Disclosed is a method for using such a system at more than one wavelength and temperature.

Abstract: An optical system, e.g., an optical fiber communication system or an optical mass storage device, which includes a linearly birefringent polarization rotator useful in an optical isolator or optical circulator, is disclosed. The rotator, which compensates for the effects of linear birefringence and is substantially antireciprocal, includes two or more material regions which are capable of subjecting incident light to elliptic birefringences. However, the sign and/or magnitude of the linear, or the sign and/or magnitude of the circular, components of the elliptic birefringences differ from region to region. Moreover, the length of each region, except the first or last region, is substantially equal to one-half the birefringent period of the region. The length of the first or last region, by contrast, is substantially equal to one-quarter the birefringent period of the region.