Fusion splicing of multi-layer optical fiber bundles

Claim 1

An optical fiber splicing apparatus for splicing optical fibers in a bundle of optical fibers having first and second optical fiber groups, each composed of a plurality of optical fibers arranged in layers, comprising: alignment mating means for holding the optical fibers of said first and second fiber groups in predetermined positions so that the axes of the corresponding pairs of individual fibers in each layer are parallel and the end faces thereof are butted together in alignment; a light source disposed adjacent one side of said bundle for emitting a light beam from said side toward the optical fibers in said bundle to heat them; a focusing optical system for focusing said light beam on at least one joint of the butted optical fibers in such a manner that the heating temperature of only the optical fibers on which the light beam is focused exceeds their melting point thereby to splice said optical fibers together; and means for moving the focusing optical system and the alignment mating means relative to each other to shift the focal position of the light beam emitted from said one side of said bundle relative to said layers thereby to change the layer of said bundle in which fibers are being spliced.

Claim 16

A method of splicing a first group of optical fibers to a second similar group of optical fibers, comprising the steps of aligning the end portions of said first and second groups of optical fibers so that the axes thereof are parallel and the endfaces thereof are in contact, forming a plurality of layers of aligned fibers, focusing a light beam on a butted joint of optical fibers in a selected one of said layers to heat only the fibers in said butted joint to a temperature in excess of the melting point of said fibers so that the endfaces of the optical fibers at said joint are fused together, effecting first relative movement between said light beam and the optical fibers in a direction perpendicular to the axes of the fibers without changing the focal length of said light beam to cause the pairs of abutted optical fibers in only said selected layer to be spliced in succession, changing the focal length of said light source in a second direction perpendicular to the direction of said first relative movement to change the effective focal position of said light beam relative to said layers, and thereafter repeating said first relative movement between said light beam and said fibers to cause the fibers in a layer which is behind the fibers of said selected layer to be spliced together in succession.

Claim 17

A method of splicing a first group of optical fibers to a second similar group of optical fibers, comprising the steps of aligning the end portions of said first and second groups of optical fibers so that the axes thereof are parallel and the endfaces thereof are in contact, forming a plurality of layers of aligned fibers, focusing a light beam on a butted joint of optical fibers in a selected one of said layers to heat only the fibers in said butted joint to a temperature in excess of the melting point of said fibers so that the endfaces of the optical fibers at said joint are fused together, effecting first relative movement between said light beam and the optical fibers in a direction perpendicular to the axes of the fibers without changing the focal length of said light beam to cause the pairs of abutted optical fibers in only said selected layer to be spliced in succession, changing the focal length of said light source in a second direction perpendicular to the direction of said first relative movement to change the effective focal position of said light beam relative to said layers, and thereafter repeating said first relative movement between said light beam and said fibers to cause the fibers in a layer which is behind the fibers of said selected layer to be spliced together in succession.

Claim 18

A method of splicing a first group of optical fibers to a second similar group of optical fibers, comprising the steps of aligning the end portions of said first and second groups of optical fibers so that the axes thereof are parallel and the endfaces thereof are in contact, forming a plurality of layers of said aligned fibers, focusing a light beam on said layers in such a manner that the beam focal point lies midway between the abutted end faces of fiber pairs in two adjacent ones of said layers to heat said abutted end faces in said two layers above their melting points simultaneously so that said two abutted fiber pairs are fusion-spliced simultaneously, effecting first relative movement between said light beam and said fibers in a direction perpendicular to the axes of the fibers without changing the focal length of said light beam so that successive pairs of abutted fiber pairs in said two adjacent layers are fusion-spliced in succession, changing the focal length of said light source in a second direction perpendicular to the direction of said first relative movement to shift the effective focal position of said light beam relative to said layers so that said light beam focuses at a position between two different adjacent layers of said aligned fibers, and thereafter repeating said first relative movement between said light beam and said fibers to splice together the fibers in said two different adjacent layers.

Claim 19

A method of splicing a first group of optical fibers to a second similar group of optical fibers, comprising the steps of aligning the end portions of said first and second groups of optical fibers so that the axes thereof are parallel and the endfaces thereof are in contact, forming a plurality of layers of said aligned fibers, focusing a light beam on said layers in such a manner that the beam focal point lies midway between the abutted end faces of fiber pairs in two adjacent ones of said layers to heat said abutted end faces in said two layers above their melting points simultaneously so that said two abutted fiber pairs are fusion-spliced simultaneously, effecting first relative movement between said light beam and said fibers in a direction perpendicular to the axes of the fibers without changing the focal length of said light beam so that successive pairs of abutted fiber pairs in said two adjacent layers are fusion-spliced in succession, changing the focal length of said light source in a second direction perpendicular to the direction of said first relative movement to shift the effective focal position of said light beam relative to said layers so that said light beam focuses at a position between two different adjacent layers of said aligned fibers, and thereafter repeating said first relative movement between said light beam and said fibers to splice together the fibers in said two different adjacent layers.