Micro-cavity laser

A system for producing laser emission in a desired wavelength band, the system comprising:

• a. A fiber waveguide, said waveguide having a first end and a second end and a tapered region therebetween, said tapered region having a tapered diameter;
• b. A micro-cavity optical resonator, said resonator having a mode path diameter, said micro-cavity resonator being constructed from a silica material doped with at least one dopant;
• c. Optical gratings, said optical gratings being position in the mode path of at least one resonant frequency of said micro-cavity optical resonator;
• d. An alignment structure, said alignment structure being arranged to locate said microcavity optical resonator and said fiber waveguide in proximity to one another so as to enable coupling between said tapered region of said fiber waveguide and said micro-cavity optical resonator;
• and,
• e. A laser pump, said laser pump being optically connected to said first end of said fiber waveguide and being arranged so as to launch one or more signals into said fiber waveguide, said optical pump signals having frequencies which excite resonances in the micro-cavity optical resonator to thereby pump at least one silica dopant to induce lasing emission within a desired output frequency band of the system.

A micro-cavity laser comprising:

• a. A first fiber waveguide, said first fiber waveguide having an evanescent coupling region, said evanescent coupling region being positioned between a first end and a second end of said fiber waveguide;
• b. A micro-cavity optical resonator, said micro-cavity optical resonator being positioned in proximity to said coupling region of said first fiber so as to evanescently couple said fiber coupling region and said micro-cavity optical resonator, said micro-cavity optical resonator having at least one optical resonance at a desired frequency output, said micro-cavity optical resonator comprising an active medium capable of providing optical gain when excited;
• and
• c. A laser pump, said laser pump being optically connected to said first end of said fiber waveguide for the purpose of exciting said gain medium.

A micro-cavity laser comprising:

• a. A fiber waveguide, said waveguide having a first end and a second end and a tapered region therebetween, said tapered region having a tapered diameter;
• b. A highly doped Erbium:Ytterbium phosphate silica micro-sphere, said microsphere being arranged so as to enable weak optical coupling between said microsphere and said tapered region of said fiber waveguide;
• and
• c. A laser pump signal, said laser pump signal being transmitted in said fiber waveguide through said tapered region, said laser signal including a frequency which excites a resonance in said silica microsphere and pumps the erbium gain medium to induce laser emission.

A micro-cavity laser system comprising:

• a. A fiber waveguide, said fiber waveguide having at least one tapered coupling region, said tapered coupling regions being located between said first end and said second end of said fiber waveguide;
• b. A plurality of micro-cavity optical resonators including a first micro-cavity resonator, each said micro-cavity optical resonator being arranged in proximity to at least one of said tapered coupling regions so as to provide optical coupling between said micro-cavity optical resonator and said fiber waveguide through at least one said tapered coupling region of said fiber waveguide, at least one of said micro-cavity optical resonators having at least one optical resonance at a desired frequency output, said first micro-cavity optical resonator including an active medium associated therewith capable of providing optical gain upon pump excitation;
• and
• c. At least one laser pump, the output of said laser pump being optically connected to said first end of said fiber waveguide to couple optical pump power into at least said first micro-cavity resonator to excite said active medium associated with said first micro-cavity optical resonator and induce lasing action such that laser output power is coupled to said fiber waveguide.

A method of fabricating a phosphorus glass microsphere for use in a micro-cavity resonator, the steps comprising:

• Melting a small piece of phosphorus glass material in a crucible,
• Stabilizing the temperature of said molten phosphorus glass,
• Placing the tip of a silica fiber taper into the molten phosphorus glass,
• Extracting the silica fiber so that a small phosphate taper is formed on the end of the silica fiber taper;
• Melting the end of the phosphate taper until a spheroid forms under surface tension,
• Quickly cooling the phosphate sphere in a manner which avoids crystallization of the phosphate in the spheroid to an extent which would interfere with the refractive properties of the spheroid as a micro-cavity optical resonator.