Multi-core fiber for a multi-spot laser probe
The present disclosure relates to a multi-core optical fiber cable (MCF). In some embodiments, an MCF comprises a plurality of cores, a cladding surrounding the plurality of cores, wherein a refractive index of one or more of the plurality of cores is greater than a refractive index of the cladding, and a coating surrounding the cladding, a distal end free of the coating and having a reduced diameter. The MCF also comprise an annular gap formed between the distal end of the MCF and the inner surface of the cannula, wherein the concentricity of the distal end of the MCF with the inner passage of the cannula is maintained.
1. A multi-spot laser probe comprising:
a probe body shaped and sized for grasping by a user;
a probe tip comprising a cannula configured for insertion into an eye, the cannula comprising:
an inner passage; and
an inner surface that defines the inner passage;
a multi-core optical fiber cable (MCF) extending at least partially through the inner passage of the cannula, the MCF comprising:
a plurality of cores;
a cladding surrounding and separating each core in the plurality of cores from each of the other cores in the plurality of cores such that laser beams traveling down the plurality of cores remain separated in their respective cores without entering any of the other cores of the plurality of cores, wherein a refractive index of one or more of the plurality of cores is greater than a refractive index of the cladding;
a coating surrounding the cladding; and
a distal end free of the coating and having a reduced diameter,
an annular gap formed between the distal end of the MCF and the inner surface of the cannula; and
a ring disposed within the annular gap to maintain concentricity of the distal end of the MCF with the inner passage of the cannula.
2. The multi-spot laser probe of claim 1 , wherein the ring is formed of a polyimide or a metal.
3. The multi-spot laser probe of claim 1 , wherein an inner diameter of the ring corresponds to an outer diameter of the distal end of the multi-core optical fiber cable.
4. The multi-spot laser probe of claim 1 , wherein an outer diameter of the ring corresponds to an inner diameter of the inner passage of the cannula.
5. The multi-spot laser probe of claim 1 , further comprising a lens disposed in the inner passage of the cannula, distal of the multi-core optical fiber cable.
6. The multi-spot laser probe of claim 5 , wherein the lens is a graded-index (GRIN) lens.
7. The multi-spot laser probe of claim 5 , wherein the distal end of the MCF abuts the lens with a positive pressure.
8. The multi-spot laser probe of claim 5 , wherein the distal end of the MCF is separated from the lens by an air gap.
9. The multi-spot laser probe of claim 5 , further comprising a window at least partially disposed in the inner passage of the cannula distal to and abutting the lens.
10. The multi-spot laser probe of claim 1 , wherein the cladding and plurality of cores are configured to keep laser beams confined to the cores while traveling the length of the plurality of cores while allowing illumination light to travel through the cladding down the length of the plurality of cores.
11. The multi-spot laser probe of claim 1 , wherein the cladding is in physical contact with each core of the plurality of cores.