Quasi-achromatic optical isolators and circulators

A quasi-achromatic optical isolator through which a light beam within a wavelength range about a nominal wavelength may propagate along a +z coordinate axis comprising:

• a first plane polarizer accepting said light beam at a first port and transmitting said light beam polarized along an orthogonal x coordinate axis;
• a first Faraday rotator receiving said light beam which has passed through said first plane polarizer;
• a first linearly birefringent plate oriented with its fast axis along the x axis and receiving said light beam which has passed through said first Faraday rotator;
• a second Faraday rotator receiving said light beam which has passed through said first linearly birefringent plate;
• a second linearly birefringent plate oriented with its fast axis along the x axis and receiving said light beam which has passed through said second Faraday rotator;
• a second plane polarizer receiving the light beam which has passed through said second linearly birefringent plate, transmitting said light beam undiminished in intensity, and exiting said light beam at a second port.

A quasi-achromatic optical isolator through which a light beam within a wavelength range about a nominal wavelength may propagate along a +z coordinate axis comprising:

• a first plane polarizer accepting said light beam at a first port and transmitting said light beam polarized along an orthogonal x coordinate axis;
• a first Faraday rotator receiving the light beam which has passed through said first plane polarizer;
• a first plurality of linearly birefringent plates receiving the light beam which has passed through said first Faraday rotator;
• a second Faraday rotator receiving the light beam which has passed through said first plurality of linearly birefringent plates;
• a second plurality of linearly birefringent plates receiving the light beam which has passed through the second Faraday rotator;
• a second plane polarizer receiving the light beam which has passed through said second plurality of linearly birefringent plates, transmitting said light beam undiminished in intensity, and exiting said light beam at a second port.

A quasi-achromatic optical circulator having first, second, third, and fourth ports comprising:

• a first polarizing beam splitter adjacent said first and said third ports of said circulator;
• two or more nonreciprocal optical rotators;
• two or more linearly birefringent plates;
• a second polarizing beam splitter adjacent said second and said fourth ports of said circulator;
• and
• said nonreciprocal optical rotators and said linearly birefringent plates being positioned in alternating sequence between said first and second polarizing beam splitters;
• whereby light entering said first port is directed to said second port;
• light entering said second port is directed to said third port;
• light entering said third port is directed to said fourth port;
• and
• light entering said fourth port is directed to said first port.

A quasi-achromatic optical circulator having first, second, third, and fourth ports that may accept a light beam within a wavelength range about a nominal wavelength and direct it to a succeeding port and comprising:

• a first polarizing beam splitter adjacent said first and said third ports of said circulator;
• a first Faraday rotator receiving a light beam which has passed through said first polarizing beam splitter;
• a first plurality of linearly birefringent plates receiving the light beam which has passed through said first Faraday rotator:
• a second Faraday rotator receiving the light beam which has passed through said first plurality of linearly birefringent plates;
• a second plurality of linearly birefringent plates receiving the light beam which has passed through said second Faraday rotator:
• and
• a second polarizing beam splitter adjacent said second and said fourth ports of said circulator for receiving the light beam which has passed through said second plurality of linearly birefringent plates and directing said light beam undiminished in intensity to said succeeding port.