Planar waveguide amplifier and laser radar device

Inventors: Kenichi Hirosawa (Tokyo, JP); Narito Samejima (Tokyo, JP); Kenichi Uto (Tokyo, JP)

Assignee: MITSUBISHI ELECTRIC CORPORATION

H01S3/06733 G01S7/4818 H01S3/0405 H01S3/094015

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Quick Facts

Patent No.: US 12665374
App. No.: 17/825,850
Granted: Jun 23, 2026
Kind: B2

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Abstract

A planar waveguide amplifier includes a planar waveguide including a flat plate-like core; a first cladding provided on a first principal face of the core; and a second cladding provided on a second principal face of the core, and signal light and pumping light travel into the planar waveguide so that the signal light and the pumping light propagate inside the core in such a manner that optical paths of the signal light and the pumping light overlap each other, and in a zig-zag manner, and the core is an amplification medium containing a rare-earth element serving as an active ion of a three-level system, and absorbs the signal light on the basis of a reduction in intensity of the pumping light.

Claims (54)

1 . A planar waveguide amplifier comprising a planar waveguide including:

a flat plate-like core to amplify signal light, with the core excited by pumping light;

a first cladding to reflect light having propagated from the core back to the core, the first cladding being provided on a first principal face of the core; and

a second cladding to reflect light having propagated from the core back to the core, the second cladding being provided on a second principal face of the core on an opposite side to the first principal face, wherein

the signal light and the pumping light travel into the planar waveguide so that the signal light and the pumping light propagate inside the core in such a manner that optical paths of the signal light and the pumping light overlap each other,

wherein a state in which the optical paths of the signal light and the pumping light overlap each other includes a state in which optical axes of the optical paths match each other and a state in which the optical axes are slightly shifted from each other such that a beam cross-section of the signal light and a beam cross-section of the pumping light overlap each other so as to include their optical axes,

wherein the signal light and the pumping light travel into the planar waveguide so that the signal light and the pumping light propagate inside the core in directions opposite to each other along a zig-zag path in the plane of the planar waveguide amplifier, so that a portion through which the signal light and the pumping light do not pass is formed inside the core, and

the core is an amplification medium that contains a rare-earth element serving as an active ion of a three-level system, and absorbs scattered light of the signal light and amplified spontaneous emission in a portion through which the pumping light does not pass.

2 . The planar waveguide amplifier according to claim 1 , wherein

the planar waveguide includes a reflective film to reflect both the signal light and the pumping light.

3 . The planar waveguide amplifier according to claim 1 , comprising

a heat sink to emit heat generated in the core, the heat sink being provided on at least one of a face of the first cladding on an opposite side to the core and a face of the second cladding on an opposite side to the core.

4 . The planar waveguide amplifier according to claim 1 , wherein

the planar waveguide includes at least either one of a first external cladding to reflect the pumping light having propagated through the first cladding back to an inside of the core through the first cladding and a second external cladding to reflect the pumping light having propagated through the second cladding back to the inside of the core through the second cladding, the first external cladding being provided on a face of the first cladding on an opposite side to the core, and the second external cladding being provided on a face of the second cladding on an opposite side to the core.

5 . The planar waveguide amplifier according to claim 4 , wherein

the planar waveguide includes a reflective film to reflect both the signal light and the pumping light.

6 . The planar waveguide amplifier according to claim 4 , comprising

a heat sink to emit heat generated in the core, the heat sink being provided on at least one of a face of the first external cladding on an opposite side to the first cladding and a face of the second external cladding on an opposite side to the second cladding.

7 . A laser radar device comprising:

a planar waveguide amplifier according to claim 1 ;