Pump coupling of double clad fibers

Apparatus for coupling light into a light propagating medium within an optical waveguide comprising:

• an optical fiber having an inner cladding of a predetermined refractive index surrounded by an outer cladding of lower index than said predetermined refractive index comprising said optical waveguide;
• and
• an optical coupler medium in optical contact with an exposed portion of said inner cladding, said coupler medium have a body portion extending transverse to the longitudinal extent of said fiber for permitting the imaging of light external of the fiber into said inner cladding,
• wherein at least part of the length of said inner cladding portion formed in said coupler medium extends transversely out of said body portion.

Apparatus for coupling light into a light propagating medium within an optical waveguide comprising;

• an optical fiber having an inner cladding of a predetermined refractive index surrounded by an outer cladding of lower index than said predetermined refractive index comprising said optical waveguide;
• and
• an optical coupler medium in optical contact with an exposed portion of said inner cladding, said coupler medium have a body portion extending transverse to the longitudinal extent of said fiber for permitting the imaging of light external of the fiber into said inner cladding,
• wherein said coupler medium includes at least one substrate having a groove within which said inner cladding portion is placed.

Apparatus for coupling light into a light propagating medium within an optical waveguide comprising:

• an optical fiber having an inner cladding of a predetermined refractive index surrounded by an outer cladding of lower index than said predetermined refractive index comprising said optical waveguide;
• and
• an optical coupler medium in optical contact with an exposed portion of said inner cladding, said coupler medium have a body portion extending transverse to the longitudinal extent of said fiber for permitting the imaging of light external of the fiber into said inner cladding,
• wherein at least one core is included in said inner cladding, said core is doped with an active element, and a reflector provided along the length of or at a terminal end of said fiber to reflect unabsorbed, residual light of the light beam propagating in said inner cladding back into said inner cladding for further absorption in said doped core,
• wherein said reflector also provides for introduction of another light beam into said inner cladding portion via said reflector.

Apparatus for coupling light into a light propagating medium within an optical waveguide comprising;

• an optical fiber having an inner cladding of a predetermined refractive index surrounded by an outer cladding of lower index than said predetermined refractive index comprising said optical waveguide;
• and
• an optical coupler medium in optical contact with an exposed portion of said inner cladding, paid coupler medium have a body portion extending transverse to the longitudinal extent of said fiber for permitting the imaging of light external of the fiber into said inner cladding,
• wherein said coupler medium is a GRIN lens.

Apparatus for coupling light into a light propagating medium within an optical waveguide comprising:

• an optical fiber having an inner cladding of a predetermined refractive index surrounded by an outer cladding of lower index than said predetermined refractive index comprising said optical waveguide;
• and
• an optical coupler medium in optical contact with an exposed portion of said inner cladding, said coupler medium have a body portion extending transverse to the longitudinal extent of said fiber for permitting the imaging of light external of the fiber into said inner cladding,
• wherein said coupler medium includes a lens for focusing the light into said inner cladding portion.

A gain medium system comprising:

• a double clad fiber (DCF) having a core doped with an active element surrounded by an inner cladding which is surrounded by an outer cladding;
• a plurality of pump light sources coupled to said double clad fiber at sequential positions along a length of the fiber;
• an optical coupler medium, having a refractive index that is substantially the same as a refractive index of said inner cladding in optical contact with an exposed portion of said inner cladding, said coupler medium have a body portion extending transverse to the longitudinal extent of said fiber for permitting the imaging of co-propagating pump light external of the fiber into said inner cladding at said positions without interrupting the continuity of said fiber core,
• further comprising a reflector coupler having a refractive index that is substantially the same as a refractive index of said inner cladding and in optical contact with an exposed portion of said inner cladding and formed at a position thereon preceding the position of at least one of said coupler mediums for reflecting co-propagating pump light unabsorbed by the fiber core back into said inner cladding.

Apparatus for coupling light comprising:

• a double clad fiber (DCF) having a core doped with an active element surrounded by an inner cladding having a predetermined refractive index and surrounded by an outer cladding;
• a pump light source providing a light beam;
• an optical coupler medium, having a refractive index that is substantially the same as said predetermined refractive index, in optical contact with an exposed portion of said inner cladding, said coupler medium have a body portion extending transverse to the longitudinal extent of said fiber for permitting the imaging of light external of the fiber into said inner cladding,
• wherein said coupler medium includes at least one substrate having a groove within which said inner cladding portion is positioned.

Apparatus for coupling light comprising:

• a double clad fiber (DCF) having a core doped with an active element surrounded by an inner cladding having a predetermined refractive index and surrounded by an outer cladding;
• a pump light source providing a light beam;
• an optical coupler medium, having a refractive index that is substantially the game as said predetermined refractive index, in optical contact with an exposed portion of said inner cladding, said coupler medium have a body portion extending transverse to the longitudinal extent of said fiber for permitting the imaging of light external of the fiber into said inner cladding,
• wherein Paid coupler medium is a GRIN lens.

Apparatus for coupling light into an optical medium comprising:

• an optical fiber comprising said medium and having a core with a refractive index n1, an inner cladding with a refractive index n2, and an outer cladding with a refractive index n3 over at least a portion of said fiber, wherein n1>n2>n3;
• a portion of said outer cladding removed from a fiber portion exposing the inner cladding therealong with said core embedded therein;
• an optical coupler medium formed on said exposed inner cladding portion of said fiber and comprising an optical material with a refractive index substantially equal to n2, in optical contact with said exposed inner cladding and substantially in coaxial alignment with the longitudinal extent of the fiber, said embedded core within said coupler medium curved transversely out of said coupler medium to exit therefrom from a side of said coupler medium;
• and
• a light source in co-axial alignment with the longitudinal extent of the fiber and having a light output coupled into said coupler medium for direct optical coupling into said inner cladding.

A method of forming a fiber space division multiplexer (FSDM) formed on a double clad fiber having a core of refractive index n1, an inner cladding of refractive index n2, and an outer cladding of refractive index n3, wherein n1>n2>n3 comprising the steps of

• removing the outer cladding along a portion of the fiber;
• embedding the exposed inner cladding fiber portion with an optical medium having a refractive index substantially equal to n2;
• and
• focusing external pump light through the medium into the inner cladding at a point where the light will be waveguided by the fiber.