US 7,024,092 B2 · Rare-earth-doped waveguide

Abstract

The present invention is to a method of adapting optical rare-earth-doped waveguide (10) having a plurality of transverse propagation modes, such that in use, signal gains of non-fundamental modes of the waveguide are attenuated relative to a signal gain of a fundamental mode of the waveguide. The waveguide (10) has a light-guiding region (45) defined by a refractive index-modifying dopant, such as Ge, which has a thermal diffusion coefficient at temperature T in the waveguide greater than a thermal diffusion coefficient of the rare-earth dopant at temperature T. The method comprises heating the waveguide (10) at the temperature T such that a concentration profile of the refractive index-modifying dopant becomes broader than a concentration profile of the rare-earth dopant.

Claims10

Dependent claims

A method of adapting an optical rare-earth-doped waveguide having a plurality of transverse propagation modes, such that in use, signal gains of non-fundamental modes of the waveguide are attenuated relative to a signal gain of a fundamental mode of the waveguide;

the waveguide having a light-guiding region defined by a refractive index-modifying dopant, and the refractive index-modifying dopant having a thermal diffusion coefficient at temperature T in the waveguide which is greater than a thermal diffusion coefficient of the rare-earth-dopant at temperature T in the waveguide, the method comprising:
treating the waveguide such that a concentration profile of the refractive index-modifying dopant becomes broader than a concentration profile of the rare earth dopant;
wherein the treatment of the waveguide comprises non-uniformly heating a length of the waveguide at the temperature T for a period of time sufficient to cause relatively greater thermal diffusion of the refractive index modifying dopant than the rare earth dopant such that the concentration profile of the refractive index-modifying dopant becomes broader than the concentration profile of the rare earth dopant;
and
such that the concentration profile of the refractive index-modifying dopant is broadened non-uniformly along the length of the waveguide.

2 more elements

A method of adapting a rare-earth-doped waveguide containing a laser cavity having a plurality of longitudinal propagation modes, such that in use, signal gains of non-fundamental longitudinal modes of the cavity are attenuated relative to a signal gain of a fundamental longitudinal mode of the cavity;

the waveguide having a light-guiding region defined by a refractive index-modifying dopant, and the refractive index-modifying dopant having a thermal diffusion coefficient at temperature T in the waveguide which is greater than a thermal diffusion coefficient of the rare-earth-dopant at temperature T in the waveguide, the method comprising:
treating end regions of the cavity such that in the end regions a concentration profile of the refractive index-modifying dopant becomes broader than a concentration profile of the rare earth dopant and broader than a concentration profile of the refractive index-modifying dopant in a region between the end regions;
wherein the treatment of the waveguide comprises non-uniformly heating a length of the waveguide at the temperature T for a period of time sufficient to cause relatively greater thermal diffusion of the refractive index modifying dopant than the rare earth dopant such that the concentration profile of the refractive index-modifying dopant becomes broader than the concentration profile of the rare earth dopant;
and
such that the concentration profile of the refractive index-modifying dopant is broadened non-uniformly along the length of the waveguide.

2 more elements

Dependencies are inferred from the claim text.

Rare-earth-doped waveguide

Life of this patent

Rare-earth-doped waveguide

Life of this patent

Abstract

Claims10