Method of making a polarization-insensitive, evanescent-wave, fused coupler with minimal environmental sensitivity

Claim 3

A method of making a polarization-insensitive optical couopler as recited in claim 1, wherein said step (a) comprises etching the first and second longitudinal segments along a length in the range of 0.5 to 2 cm.

Claim 4

A method of making a polarization-insensitive optical coupler as recited in claim 1, wherein said step (a) includes removing an outer jacket of each of the first and second single-mode optical fibers along the length of the nearly exposed cores of the first and second single-mode optical fibers.

Claim 5

A method of making a polarization-insensitive optical coupler as recited in claim 1, wherein said step (a) includes rinsing the first and second longitudinal segments of the first and second single-mode optical fibers in hydrofluoric acid to remove any room temperature vulcanizing rubber which may be surrounding the cladding of the first and second single-mode optical fibers.

Claim 6

A method of making a polarization-insensitive optical coupler as recited in claim 1, wherein said step (b) includes aligning the first and second single-mode optical fibers in a holder having alignment grooves prior to said substep (b1).

Claim 7

A method of making a polarization-insensitive optical coupler as recited in claim 1, wherein said step (d) includes the substeps of: (d1) placing a tube having ends and having a length substantially the same as the first and second longitudinal segments over the coupling region; (d2) gluing the ends of the tube to the first and second single-mode optical fibers with glue to suspend the fibers within the tube; and (d3) curing the glue.

Claim 10

A method of making a polarization-insensitive optical coupler as recited in claim 7, further comprising the step of rigidly encapsulating the nearly exposed cores of the first and second single-mode optical fibers while maintaining the parallel juxtaposition of the first and second longitudinal segments.

Claim 11

A method of making a polarization-insensitive optical coupler as recited in claim 8, wherein said encapsulating step comprises rigidly encapsulating the nearly exposed cores of the first and second single-mode optical fibers in a quartz tube.

Claim 12

A method of making a polarization-insensitive optical coupler as recited in claim 7, wherein said step (b) comprises the substeps of: (b1) wrapping portions of the first and second longitudinal segments with a material which will not substantially deform the nearly exposed cores of the first and second single-mode optical fibers; (b2) bonding the nearly exposed cores of the first and second single-mode optical fibers together while the nearly exposed cores of the first and second single-mode optical fibers are wrapped; and (b3) unwrapping the nearly exposed cores of the first and second single-mode optical fibers.

Claim 13

A method of making a .[.polarization-insenstive.]. .Iadd.polarization-insensitive .Iaddend.optical coupler as recited in claim 10, wherein said substep (b2) comprises: gluing the nearly exposed cores of the first and second single-mode optical fibers together with glue while the nearly exposed cores are wrapped; and curing the glue.

Claim 14

A method of making a polarization-insensitive optical coupler as recited in claim 10, wherein said substep (b1) comprises wrapping portions of the first and second longitudinal segments with a thin plastic sheet.

Claim 17

A method of making a polarization-insensitive optical coupler as recited in claim 13, wherein said substep (b1) comprises wrapping portions of the first and second longitudinal segments with a thin plastic sheet.

Claim 18

A method of making a polarization-insensitive optical coupler as recited in claim 14, wherein said substep (b2) comprises: gluing the nearly exposed cores of the first and second single-mode optical fibers together with glue while the nearly exposed cores are wrapped; and curing the glue.

Claim 19

A method of making a polarization-insensitive optical coupler as recited in claim 13, further comprising the step of rigidly encapsulating the nearly exposed cores of the first and second single-mode optical fibers while maintaining the parallel juxtaposition of the first and second longitudinal segments.

Claim 20

A method of making a .[.polarization-insenstive.]. .Iadd.polarization-insensitive .Iaddend.optical coupler as recited in claim 16, wherein said encapsulating step comprises rigidly encapsulating the nearly exposed cores of the first and second single-mode optical fibers in a quartz tube.

Claim 21

A method of making a polarization-insensitive optical coupler as recited in claim 16, wherein: said maintaining step (b) further comprises the substep of placing the first and second longitudinal segments under axial tenson; and said fusing step (c) comprises fusing the parallel juxtaposition portions of the first and second longitudinal segments together while the first and second longitudinal segments are maintained in parallel juxtaposition and remain under axial tension. .Iadd.

Claim 22

A method of making a polarization-insensitive optical coupler as claimed in claim 7, wherein said step (b) comprises wrapping portions of the first and second longitudinal segments with a material which will not substantially deform the nearly exposed cores of the first and second single-mode optical fibers. .Iaddend. .Iadd.20. A method of making a polarization-insensitive optical coupler as recited in claim 8, wherein said step of rigidly encapsulating the nearly exposed cores includes the substeps of: placing a tube having ends and having a length substantially the same as the first and second longitudinal segments over the coupling region; gluing the ends of the tube to the first and second single-mode optical fibers with glue to suspend the fibers within the tube; and

Claim 23

curing the glue. .Iaddend. .Iadd.21. A polarization-insensitive optical coupler prepared by a method comprising the steps of: (a) etching first and second longitudinal segments of first and second single-mode optical fibers so that each fiber has an outer cladding having a low index of refraction relative to the index of refraction of a nearly exposed core of each of the first and second single-mode optical fibers; (b) maintaining the first and second single-mode optical fibers in parallel juxtaposition with one another along a portion of each of the first and second longitudinal segments, said maintaining step comprising the substeps of: (b1) wrapping portions of the first and second longitudinal segments with a material which will not substantially deform the nearly exposed cores of the first and second single-mode optical fibers; (b2) gluing the nearly exposed cores of the first and second single-mode optical fibers together with glue while the nearly exposed cores are wrapped; (b3) curing the glue; and (b4) unwrapping the nearly exposed cores; (c) fusing together the portions of the first and second longitudinal segments maintained in parallel juxtaposition to form a coupling region; and (d) rigidly encapsulating the nearly exposed cores of the first and second single-mode optical fibers while maintaining the parallel juxtaposition of the first and second longitudinal segments, said step (d) including the substeps of: (d1) placing a tube having ends and having a length substantially the same as the first and second longitudinal segments over the coupling region; (d2) gluing the ends of the tube to the first and second single-mode optical fibers with glue to suspend the fibers within the tube; and

Claim 24

curing the glue. .Iaddend. .Iadd.21. A polarization-insensitive optical coupler prepared by a method comprising the steps of: (a) etching first and second longitudinal segments of first and second single-mode optical fibers so that each fiber has an outer cladding having a low index of refraction relative to the index of refraction of a nearly exposed core of each of the first and second single-mode optical fibers; (b) maintaining the first and second single-mode optical fibers in parallel juxtaposition with one another along a portion of each of the first and second longitudinal segments, said maintaining step comprising the substeps of: (b1) wrapping portions of the first and second longitudinal segments with a material which will not substantially deform the nearly exposed cores of the first and second single-mode optical fibers; (b2) gluing the nearly exposed cores of the first and second single-mode optical fibers together with glue while the nearly exposed cores are wrapped; (b3) curing the glue; and (b4) unwrapping the nearly exposed cores; (c) fusing together the portions of the first and second longitudinal segments maintained in parallel juxtaposition to form a coupling region; and (d) rigidly encapsulating the nearly exposed cores of the first and second single-mode optical fibers while maintaining the parallel juxtaposition of the first and second longitudinal segments, said step (d) including the substeps of: (d1) placing a tube having ends and having a length substantially the same as the first and second longitudinal segments over the coupling region; (d2) gluing the ends of the tube to the first and second single-mode optical fibers with glue to suspend the fibers within the tube; and

Claim 25

(d3) curing the glue. .Iaddend. .Iadd.22. A polarization-insensitive optical coupler as recited in claim 21, wherein said step (a) comprises etching the first and second longitudinal segments along a length in the

Claim 26

range of 0.5 to 2 cm. .Iaddend. .Iadd.23. A polarization-insensitive optical coupler as recited in claim 21, wherein said step (a) includes removing an outer jacket of each of the first and second single-mode optical fibers along the length of the nearly exposed cores of the first

Claim 27

and second single-mode optical fibers. .Iaddend. .Iadd.24. A polarization-insensitive optical coupler as recited in claim 21, wherein said step (a) includes rinsing the first and second longitudinal segments of the first and second single-mode optical fibers in hydrofluoric acid to remove any room temperature vulcanizing rubber which may be surrounding the cladding of the first and second single-mode optical fibers. .Iaddend. .Iadd.25. A polarization-insensitive optical coupler as recited in claim 21, wherein said step (b) includes aligning the first and second single-mode optical fibers in a holder having alignment grooves prior to

Claim 28

said substep (b1). .Iaddend. .Iadd.26. A polarization-insensitive optical coupler prepared by a method comprising the steps of: (a) etching first and second longitudinal segments of first and second single-mode optical fibers so that each fiber has an outer cladding having a low index of refraction relative to the index of refraction of a nearly exposed core of each of the first and second single-mode optical fibers; (b) maintaining the first and second single-mode optical fibers in parallel juxtaposition with one another along a portion of each of the first and second longitudinal segments while placing the first and second longitudinal segments under axial tension; (c) fusing the parallel juxtaposition portions of the first and second longitudinal segments together while the first and second longitudinal segments are maintained in parallel juxtaposition and remain under axial tension, so that a coupling region is formed; and (d) rigidly encapsulating the nearly exposed cores of the first and second single-mode optical fibers in a quartz tube while maintaining the parallel-juxtaposition of the first and second longitudinal segments.

Claim 29

said substep (b1). .Iaddend. .Iadd.26. A polarization-insensitive optical coupler prepared by a method comprising the steps of: (a) etching first and second longitudinal segments of first and second single-mode optical fibers so that each fiber has an outer cladding having a low index of refraction relative to the index of refraction of a nearly exposed core of each of the first and second single-mode optical fibers; (b) maintaining the first and second single-mode optical fibers in parallel juxtaposition with one another along a portion of each of the first and second longitudinal segments while placing the first and second longitudinal segments under axial tension; (c) fusing the parallel juxtaposition portions of the first and second longitudinal segments together while the first and second longitudinal segments are maintained in parallel juxtaposition and remain under axial tension, so that a coupling region is formed; and (d) rigidly encapsulating the nearly exposed cores of the first and second single-mode optical fibers in a quartz tube while maintaining the parallel-juxtaposition of the first and second longitudinal segments.

Claim 30

.Iaddend. .Iadd.27. A polarization-insensitive optical coupler as recited in claim 26, wherein said step (b) comprises the substeps of: (b1) wrapping portions of the first and second longitudinal segments with a material which will not substantially deform the nearly exposed cores of the first and second single-mode optical fibers; (b2) bonding the nearly exposed cores of the first and second single-mode optical fibers together while the nearly exposed cores of the first and second single-mode optical fibers are wrapped; and (b3) unwrapping the nearly exposed cores of the first and second

Claim 31

single-mode optical fibers. .Iaddend. .Iadd.28. A polarization-insensitive optical coupler as recited in claim 27, wherein said substep (b2) comprises: gluing the nearly exposed cores of the first and second single-mode optical fibers together with glue while the nearly exposed cores are wrapped; and curing the glue. .Iaddend. .Iadd.29. A polarization-insensitive optical coupler as recited in claim 27, wherein said substep (b1) comprises wrapping portions of the first and second longitudinal segments with a

Claim 32

thin plastic sheet. .Iaddend. .Iadd.30. A polarization-insensitive optical coupler as recited in claim 26, wherein said step (b) comprises wrapping portions of the first and second longitudinal segments with a material which will not substantially deform the nearly exposed cores of

Claim 33

the first and second single-mode optical fibers. .Iaddend. .Iadd.31. A polarization-insensitive optical coupler prepared by a method comprising the steps of: (a) etching first and second longitudinal segments of first and second single-mode optical fibers so that each fiber has an outer cladding having a low index of refraction relative to the index of refraction of a nearly exposed core of each of the first and second single-mode optical fibers; (b) maintaining the first and second single-mode optical fibers in parallel juxtaposition with one another along a portion of each of the first and second longitudinal segments, said maintaining step comprising the substeps of: (b1) wrapping portions of the first and second longitudinal segments with a material which will not substantially deform the nearly exposed cores of the first and second single-mode optical fibers; (b2) bonding the nearly exposed cores of the first and second single-mode optical fibers together while the nearly exposed cores of the first and second single-mode optical fibers are wrapped; and (b3) unwrapping the nearly exposed cores of the first and second single-mode optical fibers; (c) fusing the parallel juxtaposition portions of the first and second longitudinal segments together to form a coupling region; and (d) rigidly encapsulating the nearly exposed cores of the first and second single-mode optical fibers in a quartz tube while maintaining the parallel juxtaposition of the first and second longitudinal segments. .Iaddend.

Claim 34

the first and second single-mode optical fibers. .Iaddend. .Iadd.31. A polarization-insensitive optical coupler prepared by a method comprising the steps of: (a) etching first and second longitudinal segments of first and second single-mode optical fibers so that each fiber has an outer cladding having a low index of refraction relative to the index of refraction of a nearly exposed core of each of the first and second single-mode optical fibers; (b) maintaining the first and second single-mode optical fibers in parallel juxtaposition with one another along a portion of each of the first and second longitudinal segments, said maintaining step comprising the substeps of: (b1) wrapping portions of the first and second longitudinal segments with a material which will not substantially deform the nearly exposed cores of the first and second single-mode optical fibers; (b2) bonding the nearly exposed cores of the first and second single-mode optical fibers together while the nearly exposed cores of the first and second single-mode optical fibers are wrapped; and (b3) unwrapping the nearly exposed cores of the first and second single-mode optical fibers; (c) fusing the parallel juxtaposition portions of the first and second longitudinal segments together to form a coupling region; and (d) rigidly encapsulating the nearly exposed cores of the first and second single-mode optical fibers in a quartz tube while maintaining the parallel juxtaposition of the first and second longitudinal segments. .Iaddend.

Claim 35

.Iadd.32. A polarization-insensitive optical coupler as recited in claim 31, wherein said substep (b1) comprises wrapping portions of the first and second longitudinal segments with a thin plastic sheet. .Iaddend. .Iadd.33. A polarization-insensitive optical coupler as recited in claim 32, wherein said substep (b2) comprises: gluing the nearly exposed cores of the first and second single-mode optical fibers together with glue while the nearly exposed cores are wrapped; and

Claim 36

curing the glue. .Iaddend. .Iadd.34. A polarization-insensitive optical coupler as recited in claim 31, wherein: said maintaining step (b) further comprises the substep of placing the first and second longitudinal segments under axial tension; and said fusing step (c) comprises fusing the parallel juxtaposition portions of the first and second longitudinal segments together while the first and second longitudinal segments are maintained in parallel juxtaposition and remain under axial tension. .Iaddend. .Iadd.35. A polarization-insensitive optical coupler prepared by a method comprising the steps of: (a) etching first and second longitudinal segments of first and second single-mode optical fibers so that each fiber has an outer cladding having a low index of refraction relative to the index of refraction of a nearly exposed core of each of the first and second single-mode optical fibers; (b) maintaining the first and second single-mode optical fibers in parallel juxtaposition with one another along a portion of each of the first and second longitudinal segments while placing the first and second longitudinal segments under axial tension; (c) fusing the parallel juxtaposition portions of the first and second longitudinal segments together while the first and second longitudinal segments are maintained in parallel juxtaposition and remain under axial tension, so that a coupling region is formed; and (d) rigidly encapsulating the nearly exposed cores of the first and second single-mode optical fibers while maintaining the parallel juxtaposition of the first and second longitudinal segments, said step of rigidly encapsulating the nearly exposed cores including the substeps of: (d1) placing a tube having ends and having a length substantially the same as the first and second longitudinal segments over the coupling region; (d2) gluing the ends of the tube to the first and second single-mode optical fibers with glue to suspend the fibers within the tube; and (d3) curing the glue. .Iaddend.