Laser device

Patent metadata

Field	Value
Publication number	US-10680409-B2
Application number	US-201815914864-A
Country	US
Kind code	B2
Filing date	Mar 7, 2018
Priority date	Mar 7, 2018
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

A Distributed Feedback Laser comprises a layer stack comprising a p-layer, an n-layer which are arranged so as to form an pn-junction having an active layer in between. Within the layer stack, an index coupled grating layer or a grating layer is arranged which comprises a first, a second, and a third grating portion. The first, the second, and the third grating portions are asymmetrically arranged along a lateral dimension of the layer stack, wherein the second grating portion is formed without a grating structure.

First claim

The invention claimed is:

1. A Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′), comprising:
a layer stack ( 12 , 12 ′) having:
a p-layer ( 12 p , 12 p ′), n-layer ( 12 n , 12 n ′), which are arranged so as to form a junction having an active layer ( 12 a ′) in between;
wherein, within the layer stack ( 12 , 12 ′) an index coupled grating layer or a grating layer is arranged, which comprises a first grating portion, a second portion and a third grating portion ( 12 g 3 , 12 g 3 ′), the first grating portion, the second portion and the third grating portions ( 12 g , 12 g 1 ′, 12 g 2 , 12 g 2 ′ 12 g 3 , 12 g 3 ′) are asymmetrically arranged along a lateral dimension of the layer stack ( 12 , 12 ′);
wherein the second portion ( 12 g 2 , 12 g 2 ′) is formed without a grating structure; wherein the second portion ( 12 g 2 , 12 g 2 ′) has a lateral extension defined by L lps =(2*n 2 +1)*0.5*Λ, corresponding to multiple Λ/4 shifts, wherein Λ is the grating period and n 2 >=1.

2. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 1 , wherein the laser ( 10 , 10 ′) device comprises at the front side ( 12 f , 12 f ′) an AR-coating extending substantially perpendicular to the layers of the layer stack ( 12 , 12 ′) and/or at the back side ( 12 b , 12 b ′) an HR-coating ending substantially perpendicular to the layers of the layer stack ( 12 , 12 ′).

3. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 1 , wherein the first grating portion ( 12 g 1 , 12 g 1 ′) has larger lateral extension than the third grating portion ( 12 g 3 , 12 g 3 ′).

4. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 3 , wherein the lateral extension of the first grating portion ( 12 g 1 , 12 g 1 ′) is defined by L f =n 1 *Λ, wherein m is the number of periods, Λ is the grating period and wherein the lateral extension of the third grating portion ( 12 g 3 , 12 g 3 ′) is defined by L r =n 3 *Λ, wherein n 3 is the number of periods, and wherein n 1 and n 3 are selected so that L r <L f .

5. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 4 , wherein the total lateral extension of the lateral extension of the index coupled grating layer or the grating layer amounts to L=L f +L lps +L r .

6. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 1 , wherein the first grating portion ( 12 g 1 , 12 g 1 ′) is arranged facing to front side ( 12 f , 12 f ′) of the Laser device ( 10 , 10 ′), wherein the third grating portion ( 12 g 3 , 12 g 3 ′) is arranged at a back side ( 12 b , 12 b ′) of the Laser device ( 10 , 10 ′).

7. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 2 , wherein the HR coating at the back side ( 12 b , 12 b ′) is replaced by a reflective element or a DBR grating.

8. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 1 , wherein the p-layer ( 12 p , 12 p ′) comprises a waveguide ( 12 pw ′, 12 nw ′) arranged adjacent to the active layer ( 12 a ′) so as to form a p-waveguide layer and/or wherein the n-layer ( 12 n , 12 n ′) comprises a waveguide ( 12 pw ′, 12 nw ′) arranged adjacent to the active layer ( 12 a ′) so as to form a n-waveguide layer.

9. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 8 , wherein the index coupled grating layer or the grating layer is arranged within the p-waveguide layer or adjacent to the p-waveguide layer; and/or
wherein the index coupled grating layer or the grating layer is arranged within the n-waveguide layer or adjacent to the n-waveguide layer.

10. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 1 , wherein the index coupled grating layer or the grating layer comprises five portions with lateral extension L f , Li lps1 , L c , L lps2 , and L r , where the lateral extension of the two portions without grating are defined by L lps1 , =L lps2 =(4*n2+1)*0.25*Λ and n2>=1 so as to form multiple λ/8 phase shifts.

11. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 10 , wherein the total lateral extension of the index coupled grating layer or the grating layer amounts to L=L f +L lps1 +L c +Ll ps2 +L r , where L r <L f , so that the phase shift portions are located asymmetrically within the Laser device ( 10 , 10 ′).

12. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 1 , wherein the index coupled grating layer or grating ayer comprises (x/2+1) portions with lateral extension L f , L lps1 , L c1 L lps2 , L c2 , L lps3 . . . L lps(x/4) and L r , where the lateral extension of the (x/2+1) portions without grating are defined by L lps1 =L lps2 = . . . =L lps(x/4) =((x/2)*n2+1)*2/x)*Λ and n 2 >=1, corresponding to multiple λ/x phase shifts.

13. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 1 , wherein the Laser device ( 10 , 10 ′) is realized on a substrate comprising InP or GaAs or on a hybrid substrate comprising Si or SiNx.

14. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 1 forming an external cavity laser.

15. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 1 , wherein the grating layer comprises a complex coupled gratings.

16. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 1 monolithically integrated with a phontonic integrated circuit.

17. The Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′) according to claim 1 having etched facets or cleaved facets at a front side ( 12 f , 12 f ) or at a back side ( 12 b , 12 b ′).

18. A Single Upper Electrode Distributed Feedback Laser device ( 10 , 10 ′), comprising:
a layer stack ( 12 , 12 ′) having:
a p-layer ( 12 p , 12 p ′), n-layer ( 12 n , 12 n ′), which are arranged so as to form a pn-junction having an active layer ( 12 a ′) in between;
wherein, within the layer stack ( 12 , 12 ′) an index coupled grating layer or a grating layer is arranged, which comprises a first, a second and a third grating portion ( 12 g 3 , 12 g 3 ′), the first, the second and the third grating portions ( 12 g , 12 g 1 ′, 12 g 2 , 12 g 2 ′ 12 g 3 , 12 g 3 ′) are asymmetrically arranged along a lateral dimension of the layer stack ( 12 , 12 ′);
wherein the second grating portion ( 12 g 2 , 12 g 2 ′) is formed without a grating structure; and
wherein the index coupled grating layer or the grating layer comprises five portions with lateral extension L f , L lps1 , L c , L lps2 , and L r , where the lateral extension of the two portions without grating are defined by L lps1 =L lps2 =(4*n 2 +1)*0.25*Λ and n2>=1 so as to form multiple λ/8 phase shifts.

19. The Single Upper Electrode Distributed Feedback Laser device according to claim 1 , having an electrode extending along at least two portions of the first grating portion, the second portion and the third grating portion; or
having two opposing electrodes extending along at least two portions of the first grati

Assignees

• Fraunhofer Ges Forschung

Inventors

• Moehrle Martin

Classifications

• H01S5/124 Primary

  incorporating phase shifts · CPC title

• H01S5/1246

  plurality of phase shifts · CPC title

• H01S5/1053

  Comprising an active region having a varying composition or cross-section in a specific direction · CPC title

• H01S5/0287

  Facet reflectivity · CPC title

• H01S5/0035

  Simulations of laser characteristics · CPC title