Hollow shaft optical rotary joint

An optical rotary joint comprising:

• a first hollow tubular member including an outer circumferential surface of a first diameter;
• a second hollow tubular member including an inner circumferential surface of a second diameter larger than the first diameter, wherein the first hollow tubular member is disposed within the second hollow tubular member, and wherein at least one of the first and second hollow tubular members is rotatable about a common longitudinal axis;
• a ring shaped optical waveguide disposed between the first and second hollow tubular members and formed of light transmissive material, wherein the ring shaped optical waveguide includes first and second axial faces oriented perpendicular to the common longitudinal axis, an inner circumferential edge facing the outer circumference of the first hollow tubular member, an outer circumferential edge facing the inner circumference of the second hollow tubular member, and a circular light scattering channel formed in at least one of the first and second axial faces of the ring shaped optical waveguide;
• a first set of optical emitters arranged to face one of the outer circumferential edge of the ring shaped optical waveguide and the inner circumferential edge of the ring shaped optical waveguide, wherein the first set of optical emitters is configured to emit optical signals in a first optical spectrum;
• a second set of optical emitters arranged to face the circular light scattering channel in the ring shaped optical waveguide, wherein the second set of optical emitters is configured to emit optical signals in a second optical spectrum;
• a first optical receiver arranged to face one of the outer circumferential edge of the ring shaped optical waveguide and the inner circumferential edge of the ring shaped optical waveguide, wherein the first optical receiver is configured to receive, via the ring shaped optical waveguide, optical signals emitted in the second optical spectrum;
• and
• a second optical receiver arranged to face the circular light scattering channel in the ring shaped optical waveguide, wherein the second optical receiver is configured to receive, via the ring shaped optical waveguide, optical signals emitted in the first optical spectrum.