Polarization compensators and optical devices and systems incorporating polarization compensators

摘要

Polarization compensators and devices and systems incorporating them including polarization rotator means that employ novel polarization compensation means. The novel polarization compensator means employs the use of a variable retarder means with retardation dependent on environmental, system or operating requirements coupled with a second retarder means of substantially 90 degrees of retardation at the center specification conditions of operation. The polarization compensator may be part of either a reciprocal or a non-reciprocal device also having Faraday rotator means with specific dependence on temperature and wavelength. To improve performance significantly, temperature and/or wavelength dependence of the variable retarder of the invention is adjusted to be between about 1 and 3 times and preferably between about 1.5 and 2.5 times) the temperature and/or wavelength dependence of the Faraday rotator. The polarization rotator will therefore compensate for the variability of the Faraday rotator such that the combined apparatus shall have a reduced dependence on wavelength and/or temperature of net polarization in the reverse direction. Performance of the non-reciprocal device will be thereby improved.