Interband Cascade Lasers with Low-Fill-Factor Top Contact for Reduced Loss

Patent metadata

Field	Value
Publication number	US-2016359298-A1
Application number	US-201615172338-A
Country	US
Kind code	A1
Filing date	Jun 3, 2016
Priority date	Jun 5, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A DFB laser having a reduced fill factor and reduced loss. A plurality of spaced-apart contact openings are etched into a dielectric layer situated on top of a laser ridge having a DFB grating layer so that electrical contact between the metal top contact layer and the DFB gratings is made only in the etched openings, since all other areas of the top surface of the DFB-grated laser ridge are insulated from the metal contact layer by the dielectric. The size and shape of contact openings and their spacing are configured so that the ratio of the total area of the openings to the total area of the laser ridge provides a fill factor of less than 100%.

First claim

What is claimed is:

1 . A distributed feedback (DFB) laser having a low fill factor top contact, comprising:
a laser structure comprising a laser ridge formed on a substrate, a DFB grating layer having a DFB grating formed thereon disposed on an upper surface of the laser ridge, and a dielectric insulating film disposed on an upper surface of the DFB grating layer and covering the upper surface of the laser ridge, the laser ridge being electrically contacted to a voltage source by means of top and bottom metal contact layers; wherein the dielectric film has a predetermined plurality of spaced-apart contact openings formed therein on the upper surface of the laser ridge to provide electrical contact to the laser ridge only in the area of the ridge exposed by the openings, the remainder of the ridge being insulated from electrical contact by the dielectric film; and wherein the contact openings are configured so that a ratio of a total area of the contact openings to a total area of the upper surface of the laser ridge provides a predetermined fill factor of less than 100%.

2 . The DFB laser having a low fill factor top contact according to claim 1 , wherein the laser is an interband cascade laser (ICL).

3 . The DFB laser having a low fill factor top contact according to claim 1 , wherein the laser is a quantum cascade laser (QCL)

4 . The DFB laser having a low fill factor top contact according to claim 1 , wherein at least one of a size, a shape, and a distribution of the contact openings is random.

5 . The DFB laser having a low fill factor top contact according to claim 1 , wherein the contact openings have a predetermined uniform width w and a predetermined periodic spacing P, wherein w and P are configured to provide a predetermined fill factor w/P<100%.

6 . The DFB laser having a low fill factor top contact according to claim 1 , wherein the contact openings have a predetermined uniform width w and a predetermined periodic spacing P, wherein w and P are configured to provide a predetermined laser duty cycle.

7 . The DFB laser having a low fill factor top contact according to claim 1 , wherein each of the contact openings has a corresponding width w i and is separated from an (i+1)th neighboring contact opening by a corresponding spacing P i , wherein all of the widths w i and all of the spacings P i are configured so that the ratio of the average of all widths w i to the average of all the distances P i is less than 100%.

8 . The DFB laser having a low fill factor top contact according to claim 1 , wherein the contact openings are situated so that the openings cover the center of the laser ridge.

9 . The DFB laser having a low fill factor top contact according to claim 1 , wherein the contact openings are situated so that the contact openings do not cover the center of the laser ridge.

10 . The DFB laser having a low fill factor top contact according to claim 9 , wherein the contact openings comprise two parallel rows, each situated near an outer edge of the laser ridge.

11 . The DFB laser having a low fill factor top contact according to claim 10 , wherein the contact openings in the two parallel rows are configured so as to be aligned with each other in phase.

12 . The DFB laser having a low fill factor top contact according to claim 10 , wherein the contact openings in the two parallel rows are configured so as to be aligned with each other out of phase.

13 . The DFB interband cascade laser having a low fill factor top contact according to claim 2 , wherein the DFB grating layer is InAs or InAsSb.

15 . The DFB laser having a low fill factor top contact according to claim 1 , wherein the dielectric insulating film is SiN.

16 . The DFB laser having a low fill factor top contact according to claim 1 , further comprising a pole layer having a high refractive index relative to the contact metal or the dielectric situated near the center of the ridge between the DFB grating layer and the dielectric insulating film.

17 . The DFB laser having a low fill factor top contact according to claim 1 , wherein the pole layer is Si.

Assignees

• Us Gov Sec Navy

Inventors

• Meyer Jerry R
• Vurgaftman Igor
• Canedy Chadwick Lawrence
• Bewley William W
• Kim Chul Soo
• Kim Mijin
• Merritt Charles D

Classifications

• H01S5/3213

  asymmetric clading layers · CPC title

• H01S5/04254

  characterised by the shape · CPC title

• H01S2301/163

  Single longitudinal mode · CPC title

• H01S5/02469

  Passive cooling, e.g. where heat is removed by the housing as a whole or by a heat pipe without any active cooling element like a TEC · CPC title

• H01S5/3216

  quantum well or superlattice cladding layers · CPC title