Optical device of enhanced optical isolation at various wavelengths

An optical device comprising:

• at least one polarizer for polarizing and/or spatially separating components of a light beam, said light beam propagating along a first direction before entering into said polarizer and along a second direction after traveling through said polarizer;
• an optical rotator for rotating the light beam from said polarizer to a predetermined angle;
• and
• a magnetic element surrounding said optical rotator for generating a magnetic field with its flux direction parallel to the second direction and its magnetic field strength distributed within said magnetic element in a form of trapezoid.

An optical device comprising:

• at least one birefringent wedge for polarizing and/or spatially separating components of a light beam, said light beam propasating along a first direction before entering into said birefringent wedge and along a second direction after traveling through said birefringent wedge;
• an optical rotator for rotating the light beam from said birefrinent wedge to a predetermined angle;
• a magnetic element surrounding said optical rotator for generating a magnetic field with its flux direction parallel to the second direction;
• and
• at least one magnetic adapter attached to said magnetic element to have the direction of said magnetic field aligned with the second direction.

An optical isolator comprising:

• a first polarizer for polarizing a light beam propagated along a first direction, said light beam being deviated from the first direction by said first polarizer so that the light beam after traveling through said first polarizer propagates along a second direction;
• an optical rotator for rotating the light beam from said first polarizer to a predetermined rotation angle;
• means surrounding said optical rotator for generating a magnetic field with its direction parallel to the second direction;
• and
• a second polarizer for polarizing the rotated light beam.

An optical isolator comprising:

• a first polarizer for polarizing a light beam propagated along a first direction, said light beam being deviated from the first direction by said first polarizer so that the light beam after traveling through said first polarizer propagates along a second direction;
• an optical rotator for rotating the light beam from said first polarizer to a predetermined rotation angle, said predetermined rotation angle being varied as said magnetic field strength and direction are adjusted;
• a magnetic bushing on said optical rotator for generating a magmetic field having a direction and a strength, said direction being parallel to the second direction, said strength being essentially distributed within said magnetic bushing in a form of trapezoid, the direction and strength being distributed along the second direction and varied in spatial space as said magnetic bushing is adjusted over said rotator;
• and
• a second polarizer for polarizing the rotated light beam.

In a method of rotating a light beam transmitted along a first direction by an optical rotator, said optical rotator being enclosed within a magnet, said method comprising the steps of:

• polarizing said light beam so that the light beam after polarization is not only polarized, but also propagates along a second direction, said first direction being not parallel to said second direction;
• providing a magnetic field with its flux direction parallel to said second direction;
• and
• rotating the polarized light beam to a predetermined rotation angle.