CN113471813A

CN113471813A - Edge-emitting laser

Info

Publication number: CN113471813A
Application number: CN202110874327.1A
Authority: CN
Inventors: 王玉冰; 李泽安; 秦莉; 王立军
Original assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Current assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Priority date: 2021-07-30
Filing date: 2021-07-30
Publication date: 2021-10-01

Abstract

The invention provides an edge-emitting laser, which comprises a waveguide, wherein an interface is formed at the junction of the waveguide and air, a wedge which is symmetrical along an optical axis is formed at the laser output end of the waveguide, and the wedge is used for reducing the incident angle of laser in the waveguide at the interface so that the laser is incident into the air from the interface. Compared with the traditional edge-emitting laser, the laser edge-emitting laser has the advantages that the wedge is formed at the laser output end of the waveguide, so that the incident angle of the laser at the junction of the waveguide and the air is reduced, and the reflection of the laser at the junction is reduced. The waveguide is integrally linear and the wedge is symmetrical along the optical axis, so that the whole optical path of the optical resonant cavity is symmetrical along the optical axis, the difficulty in adjusting the optical resonant cavity is reduced, and the laser forms stable oscillation.

Description

Edge-emitting laser

Technical Field

The invention relates to the technical field of lasers, in particular to an external cavity type edge-emitting laser.

Background

The laser is a device which utilizes the stimulated radiation principle to make light oscillate in a gain medium to emit laser, the gain medium is arranged in a resonant cavity, light radiation oscillates in the resonant cavity along the axial direction, and the light radiation passes through the gain medium for multiple times and is amplified to form high-intensity laser. Compared with a common light source, the laser output by the laser has good monochromaticity, concentrated energy, and very good directivity and stability. Due to the advantages of lasers, lasers are widely used in military, industrial, agricultural, medical, communication and precision measurement, and have revolutionary breakthroughs in many fields.

The edge-emitting laser mainly comprises an optical resonant cavity, a double heterojunction and other structures. The resonator cavity includes two parallel mirror surfaces as mirrors and a rectangular waveguide to fill the gain medium. At present, most of lasers use rectangular waveguides, one end of a cavity surface is plated with a high-reflection mode, and the other end of the cavity surface is plated with an antireflection film to form a resonant cavity. However, the laser is an inner cavity type edge emitting laser, the cavity length is not adjustable, and only laser with fixed frequency can be output.

In order to solve the problem of non-adjustable cavity length, an external cavity type edge-emitting laser has been developed, as shown in fig. 1, the cavity length of the external cavity type edge-emitting laser is adjustable, and therefore the wavelength of the laser is adjustable. The waveguide 1 'is bent at the laser output end, so that the reflection of the laser 2' at the boundary of the waveguide and the air can be reduced. Compared with the intracavity edge-emitting laser of the rectangular waveguide, the frequency of the laser 2' is more stable. However, such an external cavity type edge emitting laser with a bent waveguide still has a disadvantage that since the waveguide 1' is bent at the laser output end, the entire optical path of the optical cavity is asymmetrical with respect to the optical axis, and it is difficult to adjust the cavity to make the laser form stable oscillation.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an external cavity type edge-emitting laser, wherein a wedge which is symmetrical along an optical axis is formed at the laser output end of a waveguide, so that the whole optical path of an optical resonant cavity is symmetrical along the optical axis, and the reflection of laser at the junction of the waveguide and air can be reduced by the wedge.

In order to achieve the purpose, the invention adopts the following specific technical scheme:

the edge-emitting laser provided by the invention comprises a waveguide, wherein an interface is formed at the junction of the waveguide and air, a wedge which is symmetrical along an optical axis is formed at the laser output end of the waveguide, and the wedge is used for reducing the incident angle of laser in the waveguide at the interface so that the laser is incident into the air from the interface.

Preferably, the waveguide comprises a core layer and a cladding layer, the cladding layer is positioned on two sides of the core layer, the core layer is linear, a wedge is formed at a laser output end of the core layer, laser penetrates through the core layer to enter the cladding layer under the action of the wedge, and then is diffused from the cladding layer to enter air.

Preferably, the edge-emitting laser further includes a convex lens and a reflecting mirror, the convex lens is located between the reflecting mirror and the waveguide, and the laser incident into the air is converged into parallel light by the convex lens and perpendicularly incident into the reflecting mirror; the back of the reflector is plated with an antireflection film, and the end face of the waveguide far away from the convex lens is plated with a high-reflection film.

Compared with an external cavity type edge-emitting laser with a bent waveguide, the invention can obtain the following technical effects:

1. the wedge formed by the waveguide can reduce the incidence angle of the laser at the junction of the waveguide and the air and reduce the reflection of the laser at the junction.

2. The waveguide is integrally linear and the wedge is symmetrical along the optical axis, so that the whole optical path of the optical resonant cavity is symmetrical along the optical axis, the difficulty in adjusting the optical resonant cavity is reduced, and the laser forms stable oscillation.

3. All the laser light passing through the convex lens have equal optical paths, and phase difference does not exist among the laser light beams, so that stable oscillation of the laser light is facilitated.

Drawings

FIG. 1 is a schematic structural diagram of a conventional external cavity edge-emitting laser;

fig. 2 is a schematic structural diagram of an edge-emitting laser according to an embodiment of the present invention.

Wherein the reference numerals include: the laser comprises a waveguide 1 ', a laser 2', a waveguide 1, a wedge 11, a core layer 12, a cladding layer 13, a convex lens 2, a reflector 3, an antireflection film 4, a high reflection film 5, a laser 6, a laser beam A and a laser beam B.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same blocks. In the case of the same reference numerals, their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention.

Fig. 2 shows an overall structure of an edge-emitting laser provided according to an embodiment of the present invention.

As shown in fig. 2, an edge-emitting laser provided in an embodiment of the present invention includes: the waveguide-based high-reflection optical resonator comprises a waveguide 1, a convex lens 2, a reflector 3, an antireflection film 4 and a high-reflection film 5, wherein the convex lens 2 is arranged between the waveguide 1 and the reflector 3, the antireflection film 4 is plated on the back surface (non-reflection surface) of the reflector 3, the high-reflection film 5 is plated on the end surface of the waveguide 1 far away from the convex lens 2, the waveguide 1, the convex lens 2, the reflector 3, the antireflection film 4 and the high-reflection film 5 jointly form an optical resonant cavity, and the antireflection film 4 and the high-reflection film 5 are plated on two cavity surfaces of the optical resonant cavity.

The interface is formed at the boundary of the waveguide 1 and the air, and the laser 6 transmitted in the waveguide 1 is emitted into the air from the interface, and is converted into parallel light by the convex lens 2 to be vertically incident to the end face of the optical resonant cavity (namely, to be vertically incident to the reflecting mirror 3).

A wedge 11 symmetrical along an optical axis is formed at the laser output end of the waveguide 1, and the wedge 11 is used for reducing the incidence angle of the laser 6 at the interface, so that the laser 6 is incident into air from the interface.

The waveguide 1 comprises a core layer 12 and cladding layers 13, wherein the cladding layers 13 are positioned on two sides of the core layer 12, the core layer 12 is integrally linear, and the wedge 11 is formed at the laser output end of the core layer 12 and is symmetrical along an optical axis, so that the laser output end of the core layer 12 is conical.

When the laser light 6 is transmitted to the laser output end of the core layer 12, a large amount of the laser light 6 is irradiated onto the tip wall of the wedge 11. Due to the existence of the wedge 11, the incident angle of the laser 6 at the interface is reduced, so that the incident angle of the laser 6 at the interface is smaller than the total reflection angle, the laser 6 can transmit into the cladding 13 through the core layer 12, and then is diverged from the cladding 13 and enters the air, as shown in a laser beam A in FIG. 2, the laser beam A is non-vertically irradiated on the interface, the laser beam A is converged into parallel light through the convex lens 2 and vertically enters the reflector 3, and according to the reversibility of the optical path, the laser beam A can return as it is and is finally coupled into the core layer 12.

A small amount of laser light is not directed onto the tip wall of the wedge 11 but is directed perpendicularly onto the interface, as in laser beam B in fig. 2. Most of the laser beam B vertically passes through the interface, vertically enters the reflecting mirror 3 through the convex lens 2, and returns in the original path, namely the laser beam B vertically passes through the interface after being reflected by the reflecting mirror 3 and returns to the core layer 12.

Because the wedge 11 is symmetrical along the optical axis, the core layer 12 is also symmetrical along the optical axis, so that the whole optical path of the optical resonant cavity can be determined to be symmetrical along the optical axis, the difficulty of adjusting the optical resonant cavity is reduced, and the laser 6 forms stable oscillation.

All the laser beams 6 passing through the convex lens 2 have equal optical paths, and no phase difference exists between the laser beams 6, which is beneficial to the laser beams 6 to form stable oscillation.

The positions of the convex lens 2 and the reflector 3 are adjustable, so that the cavity length of the optical resonant cavity is adjustable, and the wavelength of the laser 6 is changed by adjusting the cavity length of the optical resonant cavity, so that the laser can output laser with multiple frequencies.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "one example," "another example" or "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

The above embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An edge-emitting laser, comprising a waveguide, wherein an interface is formed at the interface of the waveguide and air, and a wedge symmetrical along an optical axis is formed at the laser output end of the waveguide, and the wedge is used for reducing the incident angle of laser light in the waveguide at the interface, so that the laser light is incident into the air from the interface.

2. The edge-emitting laser of claim 1, wherein the waveguide comprises a core layer and a cladding layer, the cladding layer is disposed on two sides of the core layer, the core layer is linear, the cleave tip is formed at a laser output end of the core layer, and the laser passes through the core layer to enter the cladding layer under the action of the cleave tip and then is emitted from the cladding layer to enter the air.

3. The edge-emitting laser according to claim 1, further comprising a convex lens and a reflecting mirror, the convex lens being located between the reflecting mirror and the waveguide, the laser light incident into the air being converged into parallel light by the convex lens and being perpendicularly incident to the reflecting mirror; and the back surface of the reflector is plated with an antireflection film, and the end surface of the waveguide far away from the convex lens is plated with a high-reflection film.