CN108270147A - A kind of laser aid and its light extraction method - Google Patents

Abstract

The embodiment of the invention discloses a laser device, which is used for reducing the space size required for packaging and reducing the complexity of optical path alignment for packaging. The device includes: an on-chip laser; the on-chip laser includes a light exit cavity surface, a reflective cavity surface and a ridge waveguide; the light exit direction corresponding to the ridge waveguide forms a target angle with the normal of the light exit cavity surface, so that along the The light propagating in the direction of the ridge waveguide is refracted when it is output from the surface of the light exit cavity, and the refracted light is perpendicular to the cleavage plane of the laser device.

Description

A kind of laser device and light output method thereof

technical field

The invention relates to the field of optoelectronic technology, in particular to a laser device and a light emitting method thereof.

Background technique

Photonic integration is a trend in the development of optoelectronics, which is expected to greatly reduce the cost of photonic systems and improve their performance. Monolithic integration and hybrid integration are two effective methods to realize photonic integration. The former is to use optical devices with different functions on the same substrate (such as indium phosphide (chemical formula: InP) substrate) and realize interconnection; the latter The latter is to select a suitable material system to make different optical devices, integrate different devices through pressure welding, bonding, etc., and realize optical interconnection through passive coupling. Since different optical devices can be realized by selecting appropriate materials and relatively mature processes, hybrid integration has the characteristics of high flexibility and low cost. In hybrid integration, most optical devices can use silicon (chemical formula: Si) optical platforms with low cost and relatively mature technology (compatible with COMS Complementary Metal Oxide Semiconductor (COMS Complementary Metal Oxide Semiconductor) technology), such as passive waveguide, MMI coupling devices, modulators, etc. However, since Si is an indirect bandgap material and has low luminous efficiency, it is not suitable as a light source. And III-V materials can make high-efficiency light sources, various types of III-V lasers such as Fabry-Perot (FP, Fabry-perot) lasers, distributed feedback (DFB, Distributed Feedback) lasers, distributed Lagg reflection ( DBR, Distributed Bragg Reflector) lasers have been successfully commercialized for many years.

A typical method for realizing hybrid integration of Group III and V lasers and Si optical devices is to attach the manufactured surface mount laser device upside down on the Si optical device, the metal pads of the two are in contact, and the metal pads are melted by heating and The cooling method welds the laser and the Si optical chip. Surface-mount laser devices generally manufacture lasers on semiconductor substrates, and monolithically integrate a passive waveguide composed of other materials behind the laser through selective etching and other processes; thus, the light from the laser is directly coupled to the passive waveguide for further processing. output or coupled with other optical devices.

However, there is a problem with the surface mount laser device that the front cavity surface has certain reflections due to the quality of the etching, which makes the laser device prone to multiple longitudinal modes when it works at high temperature, resulting in mode hopping.

In order to solve the above-mentioned problems, the surface-mounted laser device in the prior art adopts an inclined cavity surface to reduce the influence of end face reflection on the performance of the laser device, as shown in FIG. 1 .

However, the structure of the surface mount laser device in Figure 1 above makes the light output direction not perpendicular to the cleavage plane, that is, not parallel to the edge of the chip, requiring a large space for packaging, and the inclined light output also increases the optical path of the package. standard complexity.

Contents of the invention

Embodiments of the present invention provide a laser device and a light extraction method thereof, which are used to reduce the space size required for packaging and reduce the complexity of optical path alignment in packaging.

In view of this, the first aspect of the embodiment of the present invention provides a laser device, including: an on-chip laser; the on-chip laser includes a light exit cavity surface, a reflective cavity surface, and a ridge waveguide;

The light output direction corresponding to the ridge waveguide forms a target angle with the normal of the optical cavity surface, so that the light propagating along the ridge waveguide direction is refracted when output from the optical cavity surface, and the refracted light is perpendicular to the cleavage plane of the laser device.

The ridge waveguide and the light exit cavity surface in the laser device in the embodiment of the present invention can be arranged obliquely. By setting the target angle, the light exit direction of the laser device can be perpendicular to the cleavage plane, reducing the space size required for packaging. And it reduces the complexity of packaging optical path alignment.

With reference to the first aspect of the embodiments of the present invention, in the first implementation manner of the first aspect of the embodiments of the present invention, the laser device further includes: a passive waveguide;

The passive waveguide and the ridge waveguide are coupled and connected, so that the light propagating along the ridge waveguide is refracted when it is output on the surface of the light exit cavity, and the refracted light propagates along the passive waveguide;

The light output direction corresponding to the passive waveguide is perpendicular to the cleavage plane of the laser device.

In the embodiment of the present invention, the refracted light output from the surface of the light exit cavity can be transmitted through the passive waveguide, which improves the flexibility of the solution.

With reference to the first implementation manner of the first aspect of the present invention, in the second implementation manner of the first aspect provided by the embodiment of the present invention, the laser device is used for mounting on a substrate.

The laser device in the embodiment of the present invention can be mounted on the substrate, and the evanescent wave coupling output with the substrate is performed through the passive waveguide.

With reference to the first implementation manner of the first aspect of the embodiments of the present invention, in a third implementation manner of the first aspect of the embodiments of the present invention, the passive waveguide is a strip waveguide formed by etching down silicon nitride.

The embodiment of the present invention provides a specific structure of the passive waveguide, which improves the feasibility of the solution.

In combination with the first aspect of the embodiments of the present invention, any one of the first and third implementations of the first aspect, in the fourth implementation of the first aspect of the embodiments of the present invention, the corresponding ridge waveguide The light emitting direction is perpendicular to the surface of the reflective cavity.

The ridge waveguide in the embodiment of the present invention is perpendicular to the surface of the reflective cavity, which can improve the reflectivity in the cavity of the on-chip laser.

In combination with the first aspect of the embodiments of the present invention, any one of the first and third implementations of the first aspect, in the fifth implementation of the first aspect of the embodiments of the present invention, the reflective cavity surface and The surface of the light exit cavity is formed by a deep etching process.

The embodiment of the present invention provides a specific way of forming the cavity surface, which improves the feasibility of the solution.

In combination with the first aspect of the embodiments of the present invention, any one of the first and third implementations of the first aspect, in the sixth implementation of the first aspect of the embodiments of the present invention, the light exit cavity surface and The surfaces of the reflective cavity are covered with dense substances.

The cavity surface in the embodiment of the present invention is covered with a dense substance, which can isolate air and prevent damage caused by oxidation of the cavity surface.

In combination with the first aspect of the embodiments of the present invention, any one of the first and third implementations of the first aspect, in the seventh implementation of the first aspect of the embodiments of the present invention, the on-chip laser further includes Metal reflector.

In combination with the first aspect of the embodiments of the present invention, any one of the first and third implementations of the first aspect, in the eighth implementation of the first aspect of the embodiments of the present invention, the ridge waveguide adopts periodic The rectangular groove structure forms a Bragg grating with distributed feedback.

The ridge waveguide in the embodiment of the present invention can form a Bragg grating with distributed feedback, has the potential of single longitudinal mode output, and has a higher side mode suppression ratio.

The second aspect of the embodiment of the present invention provides a method for extracting light from a laser device, including:

Start the power supply of the laser device;

The laser device outputs light perpendicular to the cleavage plane of the laser device.

It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

The laser device in the embodiment of the present invention includes an on-chip laser. The on-chip laser includes a light exit cavity surface, a reflective cavity surface, and a ridge waveguide. The ridge waveguide and the light exit cavity surface can be arranged obliquely, so that the light exit direction corresponding to the ridge waveguide and the normal line of the light exit cavity surface At the target angle, by setting the target angle, the light generated by the laser can be propagated along the direction of the ridge waveguide, refracted when output on the surface of the optical cavity, and the refracted light is perpendicular to the cleavage plane of the laser device, that is, the laser device The light emitting direction is perpendicular to the cleavage plane. Since the light output direction of the laser device is perpendicular to the cleavage plane, the space size required for packaging is reduced, and the complexity of optical path alignment in packaging is reduced.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following will briefly introduce the drawings used in the description of the embodiments. Apparently, the drawings in the following description are only some embodiments of the present invention.

Fig. 1 is a schematic diagram of an embodiment of a laser device in the prior art;

Fig. 2 is a schematic diagram of an embodiment of a laser device in an embodiment of the present invention;

3 is a schematic diagram of another embodiment of the laser device in the embodiment of the present invention;

4 is a schematic diagram of the optical path of a laser device in an embodiment of the present invention;

Fig. 5 is a flow chart of an embodiment of the light extraction method of the laser device in the embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention.

The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims of the present invention and the above drawings are used to distinguish similar objects and not necessarily Describe a specific order or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of practice in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

Embodiments of the present invention provide a laser device and a light extraction method thereof, which are used to reduce the space size required for packaging and reduce the complexity of optical path alignment in packaging. First introduce the laser device in the embodiment of the present invention below, Fig. 2 is an embodiment of the laser device provided by the embodiment of the present invention, this laser device comprises: on-chip laser device 201, this on-chip laser device comprises optical cavity surface 2011, reflective cavity surface 2012 and Ridge Waveguide 2013;

The light output direction corresponding to the ridge waveguide 2013 forms a target angle with the normal of the optical cavity surface 2011, so that the light propagating along the ridge waveguide direction is refracted when output from the optical cavity surface, and the refracted light is perpendicular to the cleavage plane of the laser device .

It should be understood that light propagates along the direction of the waveguide, so the light generated by the on-chip laser will propagate along the ridge waveguide 2013, and will be refracted when it reaches the output cavity surface 2011, and the direction of the refracted light is determined by the target angle. In the embodiment of the present invention, the ridge waveguide and the light exit cavity surface can be arranged obliquely, and the target angle can be adjusted by setting the ridge waveguide and the light exit cavity surface, so that the refracted light can be perpendicular to the cleavage plane of the laser device. Specifically, the angle of the output refracted light and the target angle should satisfy the following relationship:

Where θ ₁ is the angle between the light in the ridge waveguide and the normal of the cavity surface, that is, the target angle, and θ ₁ is not equal to 0, and θ ₂ is the angle between the refracted light and the normal of the cavity surface , and θ ₂ is not equal to 0, n ₂₁ is the ratio of the refractive index of the medium into which the light enters after outputting from the surface of the optical cavity to the refractive index of the ridge waveguide 2013 .

It should also be understood that after the light is output from the light exit cavity surface 2011, it may be coupled out through an optical fiber, a lens or other means, that is, the medium may be an optical fiber, air or other, which is not limited here.

The laser device in the embodiment of the present invention includes an on-chip laser. The on-chip laser includes a light exit cavity surface, a reflective cavity surface, and a ridge waveguide. The ridge waveguide and the light exit cavity surface can be arranged obliquely, so that the light exit direction corresponding to the ridge waveguide and the normal line of the light exit cavity surface At the target angle, by setting the target angle, the light generated by the laser can be propagated along the direction of the ridge waveguide, refracted when output on the surface of the optical cavity, and the refracted light is perpendicular to the cleavage plane of the laser device, that is, the laser device The light emitting direction is perpendicular to the cleavage plane. Since the light output direction of the laser device is perpendicular to the cleavage plane, the space size required for packaging is reduced, and the complexity of optical path alignment in packaging is reduced.

Based on the above-mentioned embodiment corresponding to FIG. 2, the light generated by the on-chip laser can also be output in other ways. The laser device in the embodiment of the present invention will be described in detail below by taking several of them as examples. Please refer to FIG. 3, in the embodiment of the present invention Another embodiment of the laser device includes: an on-chip laser 301 and a passive waveguide 302;

The on-chip laser 301 includes a light exit cavity surface 3011, a reflective cavity surface 3012 and a ridge waveguide 3013. The light exit cavity surface 3011 is located at one end where the on-chip laser is connected to the passive waveguide, and the reflective cavity surface 3012 is located at the other end that is not connected to the passive waveguide; the ridge waveguide 3013 is coupled to the passive waveguide 302, and the light output direction of the ridge waveguide 3013 forms a target angle with the normal of the light exit cavity surface 3011, so that the light propagating along the direction of the ridge waveguide 3013 is refracted when output from the light exit cavity surface, and after refraction The light propagates along the passive waveguide 302;

The light emitting direction corresponding to the passive waveguide 302 is perpendicular to the cleavage plane of the laser device. In the embodiment of the present invention, since the light will propagate along the waveguide direction, that is, the light generated by the on-chip laser 301 will be transmitted along the ridge waveguide 3013 direction, reach the optical cavity surface 3011, and then be butt-coupled into the passive waveguide 302, and the light will be transmitted to After the passive waveguide, it will propagate along the direction of the passive waveguide 302, and the light output by the passive waveguide 302 can be coupled with other chips by evanescent wave, can also be output from the cleavage plane of the laser device, and can also be output in other ways , not limited here.

It should be understood that the light generated by the on-chip laser 301 will be refracted when it reaches the optical cavity surface 3011 for output. At this time, the direction of the refracted light is determined by the target angle and the position of the passive waveguide 302. In the embodiment of the present invention, the refracted light can be If the output is perpendicular to the cleavage surface, the passive waveguide 302 needs to be placed perpendicular to the cleavage surface, and then the target angle should be adjusted by setting the ridge waveguide 3013 and the light exit cavity surface 3011, so that the refracted light can go along the passive The waveguide 302 is oriented perpendicular to the output of the cleave plane of the laser device. That is to say, the light in the ridge waveguide 3013 is used as the incident light, the light in the passive waveguide 302 is used as the refracted light, and the interface of the optical cavity surface 3011 satisfies the law of refraction, as shown in FIG. 4 . Then the angle between the light transmitted in the passive waveguide and the target needs to satisfy the following relationship:

Where θ ₁ is the angle between the light in the ridge waveguide and the normal of the exit cavity surface, that is, the target angle, and θ ₁ is not equal to 0, and θ ₂ is the angle between the light in the passive waveguide and the normal of the exit cavity surface The included angle between, and θ ₂ is not equal to 0, n ₂₁ is the ratio of the refractive index of the passive waveguide to the refractive index of the ridge waveguide 3013.

In theory, it is hoped that the center of the ridge waveguide 3013 in the thickness direction, the center of the passive waveguide 302 and the normal of the light exit cavity surface 3011 are on the same plane, but in fact, due to manufacturing errors, the center of the ridge waveguide, the center of the passive waveguide and the normal of the light exit cavity surface The normals are not perfectly coplanar, but this does not affect the realization of the laser device described above.

It should also be understood that, in the embodiment of the present invention, when manufacturing the above-mentioned laser device, the on-chip laser 301 can be fabricated on the substrate first, the cavity surface of the on-chip laser 301 can be fabricated through a semiconductor process, and then a rear part of the on-chip laser can be fabricated. The passive waveguide 302 is composed of a material with a lower refractive index than the substrate. Of course, the above laser device can also be manufactured in other ways, which are not limited here.

It should also be understood that the laser device in the embodiment of the present invention can be mounted on the substrate, and the substrate can be a planar optical waveguide circuit, or a silicon photonics chip, or other substrates containing optical waveguides, which are not limited here. Specifically, the electrodes in the laser device are all coplanar, and the laser device can be flip-chip soldered on the substrate through these coplanar electrodes. After being mounted on the substrate, the light output by the on-chip laser is coupled into the passive waveguide through the butt joint, and then coupled into the optical waveguide of the substrate through the evanescent wave, thus realizing hybrid integration. Of course, the on-chip laser device can also be mounted on the substrate in other ways, which are not specifically limited here. It should also be understood that the passive waveguide in the embodiment of the present invention may be a strip waveguide formed by etching down silicon carbide or other media, or a waveguide of other shapes, which is not specifically limited here. Further, in order to avoid oxidation, it can also be covered with silicon dioxide or other media.

The laser device in the embodiment of the present invention includes an on-chip laser. The on-chip laser includes a light exit cavity surface, a reflective cavity surface, and a ridge waveguide. The ridge waveguide and the light exit cavity surface can be arranged obliquely, so that the light exit direction corresponding to the ridge waveguide and the normal line of the light exit cavity surface At the target angle, by setting the target angle, the light generated by the laser can be propagated along the direction of the ridge waveguide, refracted when output on the surface of the optical cavity, and the refracted light is perpendicular to the cleavage plane of the laser device, that is, the laser device The light emitting direction is perpendicular to the cleavage plane. Since the light output direction of the laser device is perpendicular to the cleavage plane, the space size required for packaging is reduced, and the complexity of optical path alignment in packaging is reduced.

Secondly, the laser device in the embodiment of the present invention can be mounted on the substrate to realize hybrid integration.

Thirdly, various specific structures of passive waveguides are provided in the embodiments of the present invention, which improves the flexibility of the solution.

Based on the above embodiment corresponding to FIG. 2 or FIG. 3 , in another embodiment of the laser device provided by the embodiment of the present invention, the ridge waveguide is perpendicular to the reflective cavity surface. It should be understood that the reflective cavity surface may be a curved surface or a straight surface, which is not specifically limited here.

In the embodiment of the present invention, the ridge waveguide is perpendicular to the reflective cavity surface, which can improve the reflectivity.

Based on any one of the above-mentioned multiple embodiments, in another embodiment of the laser device provided by the embodiment of the present invention, the on-chip laser further includes a metal mirror, and the surface of the light exit cavity and the surface of the reflection cavity are formed by a deep etching process, In addition, the surface of the light exit cavity and the surface of the reflective cavity are covered with dense substances. It should be understood that the dense substance may be silicon dioxide or other substances, and its thickness may be 2 microns, or other values, which are not specifically limited here.

In the embodiment of the present invention, the cavity surface of the laser is fabricated by a deep etching process, and the cavity surface is covered with a dense substance, and metal is used as a reflective mirror surface, which can effectively isolate the air and avoid catastrophic damage caused by the oxidation of the cavity surface, thereby realizing non-gas Hermetic packaging greatly simplifies the packaging process, improves packaging quality and reduces costs.

Based on any one of the above-mentioned multiple embodiments, in another embodiment of the laser device provided by the embodiment of the present invention, the ridge waveguide adopts a periodic rectangular groove structure to form a Bragg grating with distributed feedback.

The ridge waveguide in the embodiment of the present invention can form a Bragg grating with distributed feedback, has the potential of single longitudinal mode output, and has a high side-to-mode suppression ratio.

The laser device in the embodiment of the present invention is introduced above, the laser device in the embodiment of the present invention is introduced below, and the light extraction method in the embodiment of the present invention is described below, please refer to 5. The light output method of the laser device in the embodiment of the present invention includes:

501. Start the power supply of the laser device;

When the laser device needs to output light, first turn on the power of the device. It should be understood that the laser device in the embodiment of the present invention includes at least one on-chip laser, and the on-chip laser includes a light exit cavity surface, a reflective cavity surface and a ridge waveguide, wherein the light exit direction corresponding to the ridge waveguide is at a target angle to the normal of the light exit cavity surface . It should also be understood that the laser device in the embodiment of the present invention may also include a passive waveguide, which is coupled to the ridge waveguide, and the light output direction corresponding to the passive waveguide is perpendicular to the cleavage plane of the laser device.

502. The laser device outputs light perpendicular to the cleavage plane of the laser device.

After the power is turned on, the on-chip laser generates light, which propagates along the ridge waveguide and refracts when it reaches the surface of the optical cavity. According to the setting of the target angle, the light continues to propagate along the direction of the passive waveguide according to the law of refraction, and is output through the passive waveguide. The output light is perpendicular to the cleavage plane of the laser device.

The output light of the laser device in the embodiment of the present invention is perpendicular to the cleavage plane of the chip, which reduces the space size required for packaging and reduces the complexity of optical path alignment in packaging.

Those skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the above-described system, device and unit can refer to the corresponding process in the foregoing method embodiment, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or May be integrated into another system, or some features may be ignored, or not implemented. In another point, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

If the integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the essence of the technical solution of the present invention or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium , including several instructions to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (English full name: Read-OnlyMemory, English abbreviation: ROM), random access memory (English full name: Random Access Memory, English abbreviation: RAM), disk Or various media such as CDs that can store program codes.

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still understand the foregoing The technical solutions recorded in each embodiment are modified, or some of the technical features are replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. a kind of laser aid, which is characterized in that including：On piece laser；

The on piece laser includes light extraction Cavity surface, reflects Cavity surface and ridge waveguide；

The corresponding light direction of ridge waveguide and the normal of the light extraction Cavity surface are into target angle, so that along the ridge ripple The light for leading direction propagation generates refraction when the light extraction Cavity surface exports, and the light after the refraction is perpendicular to the laser The cleavage surface of device.

2. laser aid according to claim 1, which is characterized in that described device further includes：Passive wave guide；

The passive wave guide is connect with ridge waveguide-coupled so that along the light that the ridge waveguide direction is propagated, in the light extraction Refraction is generated when Cavity surface exports, and the light after the refraction is propagated along the passive wave guide；

The corresponding light direction of the passive wave guide is perpendicular to the cleavage surface of the laser aid.

3. laser aid according to claim 2, which is characterized in that the laser aid is used to be mounted on substrate.

4. laser aid according to claim 2, which is characterized in that the passive wave guide is formed for downward etch silicon nitride Slab waveguide.

5. laser aid according to any one of claim 1 to 4, which is characterized in that the corresponding light extraction of the ridge waveguide Direction is perpendicular to the reflection Cavity surface.

6. laser aid according to any one of claim 1 to 4, which is characterized in that the light extraction Cavity surface and described anti- Cavity surface is penetrated to be formed by deep etching process.

7. laser aid according to any one of claim 1 to 4, which is characterized in that the light extraction Cavity surface and described anti- It penetrates and dense matter is all covered in Cavity surface.

8. laser aid according to any one of claim 1 to 4, which is characterized in that the on piece laser further includes Metallic mirror.

9. laser aid according to any one of claim 1 to 4, which is characterized in that the ridge waveguide is using periodically Rectangular groove structure forms the Bragg grating of distributed feed-back.

10. a kind of light extraction method of laser aid, which is characterized in that including：

The laser aid startup power supply；

The laser aid output is perpendicular to the light of the cleavage surface of the laser aid.