# US 5,353,295 A · Semiconductor laser device with coupled cavities

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- Number: US 5,353,295 A
- Document ID: US5353295A
- Status: Granted
- Kind: A
- Application number: 07/927,822
- Filed: 1992-08-10
- Granted: 1994-10-04
- Earliest claimed: 1992-08-10
- Assignees: The Board of Trustees of the University of Illinois
- Inventors: Nick Holonyak, Jr.; Nada El-Zein; Fred A. Kish
- Web page: https://patentgrep.com/patent/US5353295A

## CPC

- H10P 14/69391: {the material containing aluminium, e.g. Al2O3}
- H01S 5/10: Construction or shape of the optical resonator {, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region (H01S5/20 takes precedence)}
- H01S 5/1021: {Coupled cavities (H01S5/14 takes precedence)}
- H10P 14/6312: {of Group III-V semiconductors}
- H10P 14/6322: {Formation by thermal treatments (formation by plasma treatment H10P14/6319)}
- H01S 5/026: Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers (stabilisation of output H01S5/06)
- H01S 5/1028: {Coupling to elements in the cavity, e.g. coupling to waveguides adjacent the active region, e.g. forward coupled [DFC] structures}
- H01S 5/1071: {Ring-lasers}
- H01S 5/4031: {Edge-emitting structures}
- H01S 5/4056: {emitting light in more than one direction}
- H01S 5/4068: {with lateral coupling by axially offset or by merging waveguides, e.g. Y-couplers}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL

## Abstract

In a form of the disclosure an array of coupled cavities (called minicavities) of a QWH semiconductor laser are defined by a native oxide of an aluminum-bearing III-V semiconductor material and are arranged serially end-to-end along the longitudinal direction. The native oxide confines the injected carriers and optical field within the cavities, resulting in reflection and optical feedback distributed periodically along the laser stripe. Single-longitudinal-mode operation is exhibited over an extended range. In a further form of the disclosure, two linear arrays of end-coupled minicavities are arranged side by side to obtain a two dimensional array, with resultant lateral coupling between the linear arrays. The two dimensional array exhibits mode switching and multiple switching in the light power (L) versus current (I) characteristic (L-I) with increasing current. In another form of the disclosure, a stripe laser is transversely coupled (or side-coupled) with a linear array of end-coupled minicavities. Bistability and switching are demonstrated in the light versus current (L-I) characteristic of a native-oxide-defined structure of this type. The device, with internally coupled elements and the current partitioned among the elements, exhibits a large hysteresis in the L-I curve, with switching from the stimulated to the spontaneous regime occurring over substantial power (light) and current ranges.

## Claims

### Claim 1

A semiconductor laser device, comprising:
a semiconductor active region disposed between first and second semiconductor confining layers;
an electrode array having electrode elements coupled with said first confining layer;
at least one opposing electrode coupled with said second confining layer;
the electrode elements of said array being spaced apart and forming a two-dimensional array that includes a plurality of electrode elements along a line and at least one further electrode element laterally spaced from the electrode elements of said line; and
means for applying electrical signals between said electrode elements and said opposing electrode to effect light emission in active regions defined under said plurality of electrode elements and in at least one active region defined under said at least one further electrode element, and to effect lateral coupling of said emissions.

### Claim 2 (depends on 1)

The device as defined by claim 1, wherein said at least one further electrode element comprises a single stripe which extends at least the length of said plurality of electrode elements.

### Claim 3 (depends on 1)

The device as defined by claim 1, wherein at least one further electrode element comprises a further plurality of electrode elements.

### Claim 4 (depends on 2)

The device as defined by claim 2, wherein said stripe is parallel to said line.

### Claim 5 (depends on 3)

The device as defined by claim 3, wherein said further plurality of electrode elements are along a further line parallel to said first mentioned line.

### Claim 6 (depends on 1)

The device as defined by claim 1, wherein said plurality of electrode elements comprises several electrode elements.

### Claim 7 (depends on 2)

The device as defined by claim 2, wherein said plurality of electrode elements comprises several electrode elements.

### Claim 8 (depends on 3)

The device as defined by claim 3, wherein said plurality of electrode elements comprises several electrode elements, and said at least one further electrode element comprises several further electrode elements.

### Claim 9 (depends on 1)

The device as defined by claim 1, wherein said electrode elements along said line define laser mini-cavities that are end-coupled with each other.

### Claim 10 (depends on 6)

The device as defined by claim 6, wherein said electrode elements along said line define laser mini-cavities that are end-coupled with each other.

### Claim 11 (depends on 5)

The device as defined by claim 5, wherein said electrode elements along said line define laser mini-cavities that are end-coupled with each other, and said further electrode elements along said further line define laser mini-cavities that are end-coupled with each other.

### Claim 12 (depends on 6)

The device as defined by claim 6, wherein said array includes at least one additional electrode element laterally spaced from the electrode elements of said line and said at least one further electrode element.

### Claim 13 (depends on 1)

The device as defined by claim 1, wherein said two-dimensional array comprises several rows and several columns of electrode elements.

### Claim 14 (depends on 13)

The device as defined by claim 13, wherein the electrode elements of at least a plurality of said columns define laser mini-cavities that are end-coupled with each other, and wherein at least a plurality of adjacent pairs of laser minicavities are laterally coupled with each other.

### Claim 15 (depends on 1)

The device as defined by claim 1, wherein said first confining layer is an aluminum-bearing III-V semiconductor material, and wherein at least one lateral confining region of a native oxide of said aluminum-bearing material is disposed in said confining layer between said plurality of electrode elements and said at least one further electrode element, and wherein end confining regions of a native oxide of said aluminum-bearing material are disposed between said plurality of electrode elements along said line.

### Claim 16 (depends on 2)

The device as defined by claim 2, wherein said first confining layer is an aluminum-bearing III-V semiconductor material, and wherein at least one lateral confining region of a native oxide of said aluminum-bearing material is disposed in said confining layer between said plurality of electrode elements and said at least one further electrode element, and wherein end confining regions of a native oxide of said aluminum-bearing material are disposed between said plurality of electrode elements along said line.

### Claim 17 (depends on 3)

The device as defined by claim 3, wherein said first confining layer is an aluminum-bearing III-V semiconductor material, and wherein at least one lateral confining region of a native oxide of said aluminum-bearing material is disposed in said confining layer between said plurality of electrode elements and said at least one further electrode element, and wherein end confining regions of a native oxide of said aluminum-bearing material are disposed between said plurality of electrode elements along said line.

### Claim 18 (depends on 17)

The device as defined by claim 17, wherein end confining regions of a native oxide of said aluminum-bearing material are disposed between said further plurality of electrode elements.

### Claim 19

A semiconductor laser device, comprising:
a semiconductor active region disposed between first and second semiconductor confining layers, said first and second semiconductor confining layers being of opposite conductivity type, and said first semiconductor confining layer being an aluminum-bearing III-V semiconductor material;
an oxide of said aluminum-bearing III-V semiconductor material formed in at least a portion of said first confining layer, said oxide substantially surrounding a plurality of regions of said aluminum-bearing semiconductor material of said first confining layer, said surrounded regions being arranged in serial sequence along a line;
a plurality of electrode elements coupled with respective surrounded regions of said first confining layer; and
at least one opposing electrode element coupled with said second confining layer.

### Claim 20 (depends on 19)

The device as defined by claim 19, wherein said oxide substantially surrounds at least one further region of said aluminum-bearing semiconductor material of said first confining layer, said at least one further region being laterally spaced from and adjacent to the line of said plurality of regions, and at least one further electrode element coupled with the at least one further surrounded region of said first confining layer.

### Claim 21 (depends on 20)

The device as defined by claim 20, wherein said at least one further region comprises a single elongated region adjacent to the line of said plurality of regions.

### Claim 22 (depends on 20)

The device as defined by claim 20, wherein said at least one further region comprises a plurality of further regions arranged in serial sequence and adjacent to the line of said plurality of regions.

### Claim 23 (depends on 19)

The device as defined by claim 19, wherein said plurality of regions comprises several regions.

### Claim 24 (depends on 20)

The device as defined by claim 20, wherein said plurality of regions comprises several regions.

### Claim 25 (depends on 19)

The device as defined by claim 19, wherein said electrode elements include semiconductor contacts coupled to said surrounded regions.

### Claim 26 (depends on 20)

The device as defined by claim 20, wherein said electrode elements include semiconductor contacts coupled to said surrounded regions, and said at least one further surrounded region.

### Claim 27 (depends on 25)

The device as defined by claim 25, further comprising means for applying electrical signals between said opposing electrode and said plurality of electrode elements.

### Claim 28 (depends on 26)

The device as defined by claim 26, further comprising means for applying electrical signals between said opposing electrode and said plurality of electrode elements and said at least one further electrode element.

### Claim 29 (depends on 27)

The device as defined by claim 27, wherein said means for applying electrical signals includes independent terminal connections to at least some of said plurality of electrode elements.

### Claim 30 (depends on 28)

The device as defined by claim 28, wherein said means for applying electrical signals includes independent terminal connections to at least some of said plurality of electrode elements and further plurality of electrode elements.

### Claim 31 (depends on 19)

The device as defined by claim 19, wherein said line is a straight line.

### Claim 32 (depends on 20)

The device as defined by claim 20, wherein said line is a straight line.

### Claim 33 (depends on 19)

The device as defined by claim 19, wherein said line is a curved line.

### Claim 34 (depends on 20)

The device as defined by claim 20, wherein said line is a curved line.