# US 7,466,736 B2 · Semiconductor laser diode, semiconductor optical amplifier, and optical communication device

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- Number: US 7,466,736 B2
- Document ID: US7466736B2
- Status: Granted
- Kind: B2
- Application number: 11/573,625
- Filed: 2005-06-29
- Published: 2007-11-08
- Granted: 2008-12-16
- Earliest claimed: 2004-08-13
- Assignees: NEC Corporation
- Inventors: Kiichi Hamamoto; Jan De Merlier
- Web page: https://patentgrep.com/patent/US7466736B2

## CPC

- H01S 5/227: Buried mesa structure {; Striped active layer}
- B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals
- H01S 5/028: Coatings {; Treatment of the laser facets, e.g. etching, passivation layers or reflecting layers}
- H01S 5/0655: {Single transverse or lateral mode emission}
- H01S 5/1003: {Waveguide having a modified shape along the axis, e.g. branched, curved, tapered, voids}
- H01S 5/1014: {Tapered waveguide, e.g. spotsize converter (H01S5/1064 takes precedence)}
- H01S 5/1039: {Details on the cavity length}
- H01S 5/1064: {varying width along the optical axis}
- H01S 5/2206: {based on III-V materials}
- H01S 5/2222: {having special electric properties}
- H01S 5/34306: {emitting light at a wavelength longer than 1000nm, e.g. InP based 1300 and 1500nm lasers}
- H01S 5/50: Amplifier structures not provided for in groups H01S5/02 - H01S5/30
- 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
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

To provide a semiconductor laser diode and a semiconductor optical amplifier and an optical communication device incorporating the semiconductor laser diode or the semiconductor optical amplifier which enable low power consumption and high optical output. A semiconductor laser diode according to an embodiment of the present invention is a semiconductor laser diode 100 comprised of an active waveguide, the active waveguide including a first waveguide 11a that supplies a plurality of modes including a fundamental mode; and a second waveguide 12a that is wider than the first waveguide 11a and supplies a multimode, wherein the fundamental mode is provided as an oscillation light oscillated from the active waveguide.

## Claims

### Claim 1

A semiconductor laser diode comprising an active waveguide where a fundamental mode waveguide that supplies only a fundamental mode is not provided, the active waveguide comprising:
a first waveguide that supplies a plurality of modes including a fundamental mode and a mode other than the fundamental mode; and
a second waveguide that is wider than the first waveguide and supplies a multimode,
wherein the fundamental mode is provided as an oscillation light oscillated from the active waveguide.

### Claim 2 (depends on 1)

The semiconductor laser diode according to claim 1, wherein the first waveguide supplies the fundamental mode and a first-order mode, and
the second waveguide does not allow the first-order mode as a standing wave.

### Claim 3 (depends on 1)

The semiconductor laser diode according to claim 1, wherein the second waveguide is a 1-input/N-output type 1×N (N is a positive integer) multimode interference waveguide.

### Claim 4 (depends on 1)

The semiconductor laser diode according to claim 1, wherein a taper structure having a waveguide width that is increased toward the second waveguide is provided between the second waveguide and the first waveguide.

### Claim 5 (depends on 2)

The semiconductor laser diode according to claim 2, wherein the second wave guide is a 1-input/N-output type 1×N (N is a positive integer) multimode interference waveguide.

### Claim 6 (depends on 2)

The semiconductor laser diode according to claim 2, wherein a taper structure having a waveguide width that is increased toward the second waveguide is provided between the second waveguide and the first waveguide.

### Claim 7 (depends on 3)

The semiconductor laser diode according to claim 3, wherein a taper structure having a waveguide width that is increased toward the second waveguide is provided between the second waveguide and the first waveguide.

### Claim 8

A semiconductor optical amplifier comprising an active waveguide where a fundamental mode waveguide that supplies only a fundamental mode is not provided, the active waveguide comprising:
a first wave guide that supplies a plurality of modes including a fundamental mode and a mode other than the fundamental mode; and
a second waveguide that is wider than the first waveguide and supplies a multimode,
wherein the fundamental mode is provided as oscillation light oscillated from the active waveguide.

### Claim 9 (depends on 8)

The semiconductor optical amplifier according to claim 8, wherein the first waveguide supplies the fundamental mode and a first-order mode, and
the second waveguide does not allow the first-order mode as a standing wave.

### Claim 10 (depends on 8)

The semiconductor optical amplifier according to claim 8, wherein the second waveguide is a 1-input/N-output type 1×N (N is a positive integer) multimode interference waveguide.

### Claim 11 (depends on 8)

The semiconductor optical amplifier according to claim 8, wherein a taper structure having a waveguide width that is increased toward the second waveguide is provided between the second waveguide and the first waveguide.

### Claim 12 (depends on 9)

The semiconductor optical amplifier according to claim 9, wherein the second waveguide is a 1-input/N-output type 1×N (N is a positive integer) multimode interference waveguide.

### Claim 13 (depends on 9)

The semiconductor optical amplifier according to claim 9, wherein a taper structure having a waveguide width that is increased toward the second waveguide is provided between the second waveguide and the first waveguide.

### Claim 14 (depends on 10)

The semiconductor optical amplifier according to claim 10, wherein a taper structure having a waveguide width that is increased toward the second waveguide is provided between the second waveguide and the first waveguide.

### Claim 15 (depends on 1)

An optical communication device incorporating the semiconductor laser diode according to claim 1.

### Claim 16 (depends on 8)

An optical communication device incorporating the semiconductor optical amplifier according to claim 8.