Back to results
US 8,711,471 B2Granted
High power fiber amplifier with stable output
AssigneenLight Photonics Corporation
InventorsChang Liu, Jason N. Farmer, Anmol Nijjar, Xiaojun Li
Life of this patent
Estimating the term…
Abstract
A stable, single mode fiber amplifier is described. The amplifier consists of a seed source, a passive single clad multimode fiber, an active double clad multimode fiber or a multimode fiber horn and a semiconductor laser pump source. The passive fiber is packaged on a mandrel with a compound radius of curvature such that high order modes in the fiber are stripped from the core leaving only the fundamental mode. This fiber is then spliced to a multimode active fiber of similar core diameter. By exciting only the fundamental mode of this active fiber, stable single mode amplification is achieved.
Claims34
A mode filter, comprising:
- an input multimode fiber section operable to receive an optical input beam;
- a passive mode filtering section operable to attenuate fiber modes in the input optical beam as received from the input multimode fiber section, wherein the passive mode filtering section provides at least about 3 dB of attenuation of an LP11 mode propagating in the mode filtering fiber section;
- and
- an output multimode fiber section situated to receive the mode filtered optical beam and situated so that the mode filtered optical beam substantially excites only a lowest order mode in the output multimode fiber section, wherein the passive mode filtering section comprises a multimode fiber section that includes a tapered portion having an input core cross-sectional area, a minimum taper core cross-sectional area, and an output core cross-sectional area, wherein the input and output core cross-sectional areas define multimode cores and the minimum taper core cross-sectional area defines a few mode core.
1 more element
A mode filter, comprising:
- an input multimode fiber section operable to receive an optical input beam;
- a passive mode filtering section operable to attenuate fiber modes in the input optical beam as received from the input multimode fiber section, wherein the passive mode filtering section provides at least about 3 dB of attenuation of an LP11mode propagating in the mode filtering fiber section;
- and
- an output multimode fiber section situated to receive the mode filtered optical beam and situated so that the mode filtered optical beam substantially excites only a lowest order mode in the output multimode fiber section, wherein the passive mode filtering section comprises a multimode fiber section that includes a tapered portion having an input core cross-sectional area, a minimum taper core cross-sectional area, and an output core cross-sectional area, wherein the input and output core cross-sectional areas define multimode cores and the minimum taper core cross-sectional area defines a single mode core.
1 more element
A mode filter, comprising:
- an input multimode fiber section operable to receive an optical input beam;
- a passive mode filtering section operable to attenuate fiber modes in the input optical beam as received from the input multimode fiber section, wherein the passive mode filtering section provides at least about 3 dB of attenuation of an LP11 mode propagating in the mode filtering fiber section;
- and
- an output multimode fiber section situated to receive the mode filtered optical beam and situated so that the mode filtered optical beam substantially excites only a lowest order mode in the output multimode fiber section, wherein the mode filtering section comprises a multimode fiber section having at least a first bend and a second bend associated with first and second axis of curvature, respectively, wherein the first and second axes of curvature are not collinear.
1 more element
An optical amplifier system, comprising:
- a light source for producing a seed light beam;
- a mode filter operable to receive the seed light beam, the mode filter comprising a passive multimode optical fiber that includes a mode filtering fiber portion configured to provide an attenuation of at least 3 dB to an LP11 mode, the mode filtering fiber portion includes a passive mode filtering section, wherein the passive mode filtering section comprises a multimode fiber section that includes a tapered portion having an input core cross-sectional area, a minimum taper core cross-sectional area, and an output core cross-sectional area, wherein the input and output core cross-sectional areas define multimode cores and the minimum taper core cross-sectional area defines a few mode core, and
- a multimode fiber amplifier, comprising a rare earth doped multimode amplifier optical fiber configured to receive the mode filtered seed light beam, and a pump light source configured to direct pump light into the rare earth doped multimode amplifier optical fiber and produce optical gain.
An optical amplifier system, comprising:
- a light source for producing a seed light beam;
- a mode filter operable to receive the seed light beam, the mode filter comprising a passive multimode optical fiber that includes a fiber portion configured to provide an attenuation of at least 3 dB to an LP11 mode, and
- a multimode fiber amplifier, comprising a rare earth doped multimode amplifier optical fiber configured to receive the mode filtered seed light beam, and a pump light source configured to direct pump light into the rare earth doped multimode amplifier optical fiber and produce optical gain,
- wherein the mode filter multimode fiber is wound along a path with a non-constant axis of curvature and a radius of curvature such that the non-constant axis of curvature and the radius of curvature create a substantially higher loss for the at least one higher order mode than for the fundamental mode.
1 more element
An optical amplifier system, comprising:
- a light source for producing a seed light beam;
- a mode filter operable to receive the seed light beam, the mode filter comprising a passive multimode optical fiber that includes a fiber portion configured to provide an attenuation of at least 3 dB to an LP11 mode, and
- a multimode fiber amplifier, comprising a rare earth doped multimode amplifier optical fiber configured to receive the mode filtered seed light beam, and a pump light source configured to direct pump light into the rare earth doped multimode amplifier optical fiber and produce optical gain,
- wherein the mode filter multimode fiber includes a bent fiber portion configured to provide substantial attenuation for higher order modes.
1 more element
An optical amplifier system, comprising:
- a light source for producing a seed light beam;
- a mode filter operable to receive the seed light beam, the mode filter comprising:
- an input multimode fiber section operable to receive an optical input beam;
- a passive mode filtering section operable to attenuate fiber modes in the input optical beam as received from the input multimode fiber section, wherein the passive mode filtering section provides at least about 3 dB of attenuation of an LP11 mode propagating in the mode filtering fiber section;
- and
- an output multimode fiber section situated to receive the mode filtered optical beam and situated so that the mode filtered optical beam substantially excites only a lowest order mode in the output multimode fiber section, wherein the passive mode filtering section comprises a multimode fiber section that includes a tapered portion having an input core cross-sectional area, a minimum taper core cross-sectional area, and an output core cross-sectional area, wherein the input and output core cross-sectional areas define multimode cores and the minimum taper core cross-sectional area defines a single mode core:
- and
- a multimode fiber amplifier, comprising a rare earth doped multimode amplifier optical fiber configured to receive the mode filtered seed light beam, and a pump light source configured to direct pump light into the rare earth doped multimode amplifier optical fiber and produce optical gain.
5 more elements
Dependencies are inferred from the claim text.