Apparatus and method for compensating for and using mode-profile distortions caused by bending optical fibers

A method comprising:

• providing a fiber having a plurality of substantially parallel core regions, including a first core region and a second core region, wherein a length of the fiber is configured to have a straight section and a first curved section, and wherein the first curved section has a first bend radius;
• guiding signal light primarily in the second core region in the straight section of the fiber;
• guiding the signal light from the second core region into the first core region between the straight section and the first curved section of the fiber;
• and
• guiding the signal light primarily in the first core region in the first curved section of the fiber, wherein providing of the fiber includes
• configuring the second core region to be contiguous with the first core region.

A method comprising:

• providing a fiber having a plurality of substantially parallel core regions, including a first core region and a second core region, wherein a length of the fiber is configured to have a straight section and a first curved section, and wherein the first curved section has a first bend radius;
• guiding signal light primarily in the second core region in the straight section of the fiber;
• guiding the signal light from the second core region into the first core region between the straight section and the first curved section of the fiber;
• and
• guiding the signal light primarily in the first core region in the first curved section of the fiber, wherein providing of the fiber includes
• providing a third core region parallel to the first core region and the second core region.

A method comprising:

• providing a fiber having a plurality of substantially parallel core regions, including a first core region and a second core region, wherein a length of the fiber is configured to have a straight section and a first curved section, and wherein the first curved section has a first bend radius;
• guiding signal light primarily in the second core region in the straight section of the fiber;
• guiding the signal light from the second core region into the first core region between the straight section and the first curved section of the fiber;
• and
• guiding the signal light primarily in the first core region in the first curved section of the fiber, wherein providing of the fiber includes providing a third core region parallel to the first core region and the second core region, the method further comprising:
• not amplifying the signal light in the second core region;
• amplifying the signal light in the first core region;
• and
• filtering the signal light in the third core region.

A method comprising:

• providing a fiber having a plurality of substantially parallel core regions, including a first core region and a second core region, wherein a length of the fiber is configured to have a straight section and a first curved section, and wherein the first curved section has a first bend radius;
• guiding signal light primarily in the second core region in the straight section of the fiber;
• guiding the signal light from the second core region into the first core region between the straight section and the first curved section of the fiber;
• and
• guiding the signal light primarily in the first core region in the first curved section of the fiber, wherein providing of the fiber includes providing a third core region parallel to the first core region and the second core region, the method further comprising:
• not amplifying the signal light in the second core region;
• amplifying the signal light in the first core region;
• filtering the signal light in the third core region;
• positioning the fiber to have a straight section and a subsequent curved section, the curved section having a first portion with a first bend radius separated from the straight section by a second portion having a second bend radius;
• launching the signal light into the second core region at an end of the straight section;
• transferring the signal light into the third core region from the second core region in the second portion at a juncture of the straight and curved sections;
• configuring the curved section of the fiber to the first bend radius;
• and
• transferring the signal light into the first core region from the third core region.

A method comprising:

• providing a fiber having a plurality of substantially parallel core regions, including a first core region and a second core region, wherein a length of the fiber is configured to have a straight section and a first curved section, and wherein the first curved section has a first bend radius;
• guiding signal light primarily in the second core region in the straight section of the fiber;
• guiding the signal light from the second core region into the first core region between the straight section and the first curved section of the fiber;
• and
• guiding the signal light primarily in the first core region in the first curved section of the fiber, wherein providing of the fiber includes providing a third core region parallel to the first core region and the second core region, the method further comprising:
• not amplifying the signal light in the second core region;
• amplifying the signal light in the first core region;
• filtering the signal light in the third core region;
• positioning the fiber to have a straight section and a subsequent curved section, the curved section having a first portion with a first bend radius separated from the straight section by a second portion having a second bend radius;
• launching the signal light into the second core region at an end of the straight section;
• transferring the signal light into the third core region from the second core region in the second portion at a juncture of the straight and curved sections;
• configuring the curved section of the fiber to the first bend radius;
• and
• transferring the signal light into the first core region from the third core region, wherein the second core region is separated from the third core region by a cladding region, and the third core region is separated from the first core region by a cladding region.

An apparatus comprising:

• a fiber having a plurality of substantially parallel core regions, including a first core region and a second core region;
• means for guiding signal light primarily in the first core region in a first section of the fiber;
• means for transitioning the signal light into the second core region in a second section of the fiber;
• and
• means for guiding signal light primarily in the second core region in the second section of the fiber.