Granted Patent B2

US 12,586,985 · App. 18/185,721 · Granted Mar 24, 2026

Inventors: Alexandre Garreau (Antony, FR); Jean Francois Paret (Arpajon, FR)

Assignee: Nokia Solutions and Networks Oy

H01S5/1228

Abstract

Claims (53)

1 . A distributed feedback laser comprising:

an optical waveguide gain medium configured to amplify light at a laser wavelength;

a first optical grating comprising a first plurality of index-modulated grating structures having a period Λ disposed on one side of the optical waveguide gain medium; and

a second optical grating comprising a second plurality of loss-modulated grating structures having a same period Λ, with an offset of Λ/4±Λ/8 from the first plurality of index-modulated grating structures, disposed on another side of the optical waveguide gain medium, opposite the first optical grating.

2 . The distributed feedback laser according to claim 1 , wherein the first optical grating has a substantially zero absorption coefficient; and wherein the second optical grating has a non-zero absorption coefficient.

3 . The distributed feedback laser according to claim 1 , wherein the first optical grating is configured to work at a first order of the laser wavelength; and wherein the second optical grating is configured to work at the first order of the laser wavelength.

4 . The distributed feedback laser according to claim 1 , wherein the first optical grating has a first photoluminescence peak wavelength larger than the laser wavelength; and wherein the second optical grating has a second photoluminescence peak wavelength less than the laser wavelength.

5 . The distributed feedback laser according to claim 1 , wherein first plurality of grating structures are in a first epitaxial film or layer of a first group III-V semiconductor; and wherein the second plurality of grating structures are in a second epitaxial film or layer of a second group III-V semiconductor.

6 . The distributed feedback laser according to claim 1 , further comprising:

a first electrode;

a first electrical contact region between the first electrode and the first optical grating;

a first spacer region between the optical waveguide gain medium and the first optical grating;

a second electrode;

a second electrical contact region between the second electrode and the second optical grating; and

a second spacer region between the optical waveguide gain medium and the second optical grating.

7 . The distributed feedback laser according to claim 6 , wherein the first electrical contact region and the first spacer region are comprised of one of an n-doped group III-V semiconductor or a p-doped group III-V semiconductor; and wherein the second electrical contact region and the second spacer region are comprised of the other of the n-doped group III-V semiconductor or the p-doped group III-V semiconductor.

8 . The distributed feedback laser according to claim 6 , wherein η Spacer1 <η IndexG <η wgm ; wherein η wgm is a refractive index of the optical waveguide gain medium, η IndexG is a refractive index of the first optical grating, and η Spacer1 is a refractive index of the first spacer region; and

wherein η Spacer2 <η wgm <η LossG ; wherein η Spacer2 is a refractive index of the second spacer region, η wgm is the refractive index of the optical waveguide gain medium, and η LossG is a refractive index of the second optical grating.

9 . The distributed feedback laser according to claim 1 , wherein the optical waveguide gain medium is based on separate confinement heterostructure (SCH) and multiple quantum wells (MQW).

10 . A method of manufacturing a distributed feedback laser comprising:

a) providing a substrate;

b) providing a first optical grating over the substrate comprising a first plurality of grating structures having a period Λ;

c) providing an optical waveguide gain medium over the first optical grating configured to amplify light at a laser wavelength; and

d) providing a second optical grating over the optical waveguide gain medium comprising a second plurality of grating structures having the period Λ with an offset of Λ/4±Λ/8 from the first plurality of grating structures;

wherein the first optical grating comprises one of index-modulated grating structures or loss-modulated grating structures, and the second optical grating comprises the other of the index-modulated grating structures or the loss-modulated grating structures.

11 . The method according to claim 10 , wherein the step b) includes forming the first plurality of grating structures in a first epitaxial film or layer of a first group III-V semiconductor; and wherein step d) includes forming the second plurality of grating structures in a second epitaxial film or layer of a second group III-V semiconductor.

12 . The method according to claim 11 , wherein the step b) also comprises:

providing a first electrical contact region between the substrate and the first optical grating; and

providing a first spacer region between the optical waveguide gain medium and the first optical grating;

wherein the step d) also comprises:

providing a second spacer region between the optical waveguide gain medium and the second optical grating;

providing a second electrical contact region on the second optical grating; and

wherein the method further comprises:

providing a first electrode on the first electrical contact region; and

providing a second electrode on the second electrical contact region.

13 . The method according to claim 12 , wherein the first electrical contact region and the first spacer region are comprised of one of an n-doped group III-V semiconductor or a p-doped group III-V semiconductor; and wherein the second electrical contact region and the second spacer region are comprised of the other of the n-doped group III-V semiconductor or the p-doped group III-V semiconductor.

14 . The method according to claim 12 , wherein η Spacer1 <η IndexG <η wgm ; η wgm is a refractive index of the optical waveguide gain medium, and η IndexG is a refractive index of the first optical grating; and

wherein η Spacer2 <η wgm <η LossG ; wherein η Spacer2 is a refractive index of the second spacer region, η wgm is the refractive index of the optical waveguide gain medium, and η LossG is a refractive index of the second optical grating.

15 . The method according to claim 12 , wherein the step b) comprises:

depositing the first electrical contact region on the substrate;

depositing a first grating material layer on the first electrical contact region;

depositing a first spacer material layer on the first grating material layer;

etching the first spacer material layer and the first grating material layer to form the first plurality of grating structures; and

depositing additional material between the first plurality of grating structures, comprising a same material as the first electrical contact region and the first spacer layer to form the first spacer region;

wherein the step c) comprises:

depositing an optical waveguide gain medium material layer on the first spacer layer;

wherein the step d) comprises:

depositing a second spacer material layer over the optical waveguide gain medium material layer;

depositing a second grating material layer over the second spacer material layer;

depositing a second electrical contact material layer over the second grating material layer;

etching the second spacer material layer, the second grating material layer, and the second electrical contact material layer to form the second plurality of grating structures;

depositing additional material between the second plurality of grating structures, comprising a same material as the second electrical contact material layer and the second spacer material layer to form the second spacer region and the second electrical contact region; and

etching at least one of the second electrical contact region, the second spacer region, the optical waveguide gain medium, and the first spacer region into a ridge waveguide.

Assignments (2)

Priority Claims (1)

Continuity (1)

References Cited (16)