Polarization preserving bidirectional optical element

An optical device, comprising:

• first and second 45° Faraday rotators;
• and
• a 45° polarizer located between the first and second Faraday rotators, the first and second 45° Faraday rotators being arranged with respect to one another so that only optical energy that is in a first polarization state is able to propagate through the optical device when the optical energy is incident upon the optical device from either first or second directions that are opposite to one another.

An optical device, comprising:

• first and second 45° Faraday rotators;
• and
• a 45° polarizer located between the first and second Faraday rotators, the first and second 45° Faraday rotators being arranged with respect to one another so that only optical energy that is in a first polarization state is able to propagate through the optical device when the optical energy is incident upon the optical device from a first direction and only optical energy that is in a second polarization state is able to propagate through the optical device when the optical energy is incident upon the optical device from a second direction opposite to the first direction, the first and second polarization states being orthogonal to one another