Integrated optics coupler

Claim 2

A coupler according to claim 1 wherein the decorrelating means is a multi-mode guide segment (54) of length sufficient to decorrelate symmetric mode light with respect to anti-symmetric mode light passing through the multi-modal waveguide segment towards the output end of the central waveguide.

Claim 3

A coupler according to claim 2 wherein the central waveguide comprises a mono-modal waveguide segment (60) coupling the multi-mode guide segment (54) to the output end of the central waveguide (52).

Claim 4

A coupler according to claim 2 or 3, wherein the central waveguide comprises a tapered waveguide segment (66) coupling the multi-mode waveguide segment (54) to the output end of the central waveguide (52).

Claim 5

A coupler according to claims 3 and 4, wherein the mono-modal waveguide segment (60) couples the tapered waveguide segment (66) to the output end of the central waveguide (52).

Claim 6

A coupler according to any one of the preceding claims, and comprising a further integrated optical mono-modal waveguide (26) coupled with the input waveguide (24) to the central waveguide.

Claim 7

A spatial mode decorrelator for receiving broadband laser light from a broadband light source at an optical input and for providing a propagating light ray and a counterpropagating light ray to respective first and second inputs of a closed optical path comprising a substrate having a first, second, third, fourth, fifth and sixth waveguide segments, each waveguide segment having a first and second end, the first waveguide segment having a first end coupled to the optical input to receive broadband light from the broadband light source, the second and third optical wave guide segments having respective first ends coupled to the first optical waveguide second end, the third optical waveguide segment second end being coupled to the fourth optical waveguide segment first end, the fourth optical waveguide segment second end being coupled to the fifth and sixth waveguide segment first ends, the fifth and sixth optical waveguide segment second ends being respectively coupled to the first and second inputs of the closed optical path, the third optical waveguide segment being dimensioned to be multi-modal and to propagate symmetric and anti-symmetric mode beams of the broadband laser light with different velocities, the third segment having a length sufficient to introduce a delay time between the beams sufficient to exceed the decorrelation time of respective beams.

Claim 8

A spatial mode decorrelator according to claim 7, wherein the first and second optical waveguide segments are dimensioned to propagate broadband laser light received from the optical input in a single mode.

Claim 9

A spatial mode decorrelator according to claims 7 or 8, wherein the third optical waveguide segment is dimensioned to propagate broadband laser light received from the second end of the first and second optical waveguide segments in a symmetric mode beam and in an anti-symmetric mode beam.

Claim 10

A spatial mode decorrelator according to claim 7, 8 or 9 wherein the fourth optical waveguide segment is dimensioned to propagate broadband laser light received from the second end of the third optical waveguide in a symmetric mode beam, anti-symmetric mode beam light being radiated into the substrate.

Claim 11

A spatial mode decorrelator for receiving broadband laser light at an optical input and for providing propagating and a counterpropagating light to respective first and second inputs of a closed optical path, the decorrelators comprising a substrate having an input waveguide segment means for receiving broadband laser light at the optical input, the input segment means being arranged to propagate a symmetric light beam and asymmetric mode light beam into a first optical node, a decorrelator waveguide segment means formed in the substrate in a central optical waveguide means and being responsive to the first optical node for coupling the symmetric light beam and the asymmetric light beam to a second optical node, the symmetric light beam and the asymmetric light beam each moving with a different velocity, the central multi-modal optical waveguide means having an optical waveguide segment length sufficient to introduce a delay time between the symmetric and asymmetric beams sufficient to exceed the decorrelation time of respective beams, and an output waveguide segment formed as a Y-shaped assembly of two output mono-modal optical wave-guides joined at the second optical node for coupling the symmetrical light into a propagating and a counterpropagating light beam, each respective propagating and a counterpropagating light beam being coupled into first and second inputs of a closed optical path.