US 6,587,273 B2 · Beam splitting device

Abstract

An improved design of beam splitting device is described that is formed by cutting a birefringent material to predetermined dimensions. The beam splitting device resolves input light into mutually orthogonal linearly polarised beams. The mutually orthogonal linearly polarised beams propagate on either side of an axis as defined by the propagation axis of the input light. Such beam splitting devices lends themselves to a reduction in the overall dimensions of an optical system. In particular an optical circulator is described that employs such beam splitting devices so as to allow the transfer of light from a first optical port to a second optical port, and from the second port to a third. Not only does the employment of such beam splitting devices significantly reducing the dimensions of the optical system it also renders the device simpler to align.

Claims23

Dependent claims

An optical birefringent device comprising a block of birefringent material, said block of birefringent material having an input face and an opposite output face parallel to the input face, the block having an optical axis, the input face and the output face being disposed at a non-perpendicular angle to a propagation axis defined by the propagation direction of an input optical beam, while the optical axis is disposed at a second predetermined angle to the propagation axis, the incidence angle and the second angle being both selected such that the input optical beam entering said birefringent block is separated into first and second beams with mutually orthogonal linear polarisations, said first and second beams being propagated so as to be located on opposite sides of said propagation axis.

An optical circulator for coupling a first light sending port, a second light sending and receiving port and a third light receiving port, said circulator having a longitudinal axis along which there is located a plurality of elements comprising:

a) a first optical birefringent device for receiving light from said first port, guiding light to said second port, and for separating and combining mutually orthogonal polarised beams;
b) a first polarisation rotator for changing the polarisation of beams from mutually orthogonal to parallel and from parallel to mutually orthogonal;
c) means for bending collimated light at an angle dependent upon its direction of polarisation;
d) a second optical birefringent device for guiding light to and receiving light from said second port, and for combining and separating mutually orthogonal polarised beams;
and
wherein said optical birefringent devices each have an associated propagation axis defined by the propagation direction of the combined light, an input face and an opposite output face parallel to each other and disposed non-perpendicularly to the propagation axis at an angle dependent on the orientation of optical axis of the respective birefringent device, said angle being selected so as to propagate said separated beams on opposite sides of said propagation axis.

3 more elements

Dependencies are inferred from the claim text.

Beam splitting device

Life of this patent

Beam splitting device

Life of this patent

Abstract

Claims23