阅读说明：本技术 一种集成环形谐振器的边发射半导体激光器 (Edge-emitting semiconductor laser integrated with ring resonator ) 是由 韩宇 向欣 李鸿建 陈云飞 张翼菲 陈志标 于 2020-08-20 设计创作，主要内容包括：本发明涉及激光器技术领域,提供了一种集成环形谐振器的边发射半导体激光器,包括输入端口、将信号引至所述输入端口的波导以及用于旁瓣过滤的环形谐振腔,所述环形谐振腔有四个端口,其中两个端口与所述波导重合,且所述环形谐振腔的另外两个端口至少一个设有可将光源垂直输出的反射组件。本发明的一种集成环形谐振器的边发射半导体激光器,通过集成环形谐振器来实现旁波的过滤、以及导出光到其它位置,使得激光器的谱线更少干扰,减少激光器模式跳跃的可能性,从而提高激光器的信号输出以及边模抑制比等器件性能,然后通过制作在芯片上的反射组件,将部分光导出到垂直面,从而实现单个芯片同时有传统出光面和垂直出光位置。(The invention relates to the technical field of lasers, and provides an edge-emitting semiconductor laser integrated with a ring resonator, which comprises an input port, a waveguide for guiding signals to the input port, and a ring resonant cavity for side lobe filtration, wherein the ring resonant cavity is provided with four ports, two ports are overlapped with the waveguide, and at least one of the other two ports of the ring resonant cavity is provided with a reflecting component capable of vertically outputting a light source. According to the edge-emitting semiconductor laser of the integrated ring resonator, the filtering of side waves and the light emission to other positions are realized through the integrated ring resonator, so that the spectral line of the laser is less interfered, the possibility of mode hopping of the laser is reduced, the performances of devices such as signal output, edge mode suppression ratio and the like of the laser are improved, and then part of light is led out to a vertical plane through the reflection assembly manufactured on the chip, so that a single chip has a traditional light emitting surface and a vertical light emitting position at the same time.)

1. An edge-emitting semiconductor laser integrated with a ring resonator, comprising: the optical fiber filter comprises an input port, a waveguide for guiding signals to the input port and an annular resonant cavity for side lobe filtration, wherein the annular resonant cavity is provided with four ports, two ports are overlapped with the waveguide, and at least one of the other two ports of the annular resonant cavity is provided with a reflecting component capable of vertically outputting a light source.

2. An integrated ring resonator edge-emitting semiconductor laser as claimed in claim 1 wherein the relationship between the radius R of the ring cavity and its resonance order m is:

3. An integrated ring resonator edge-emitting semiconductor laser as claimed in claim 1 wherein: the ring resonator is also cascaded with a plurality of additional ring resonators.

4. An integrated ring resonator edge-emitting semiconductor laser as claimed in claim 1 wherein: the ring resonant cavity adopts passive waveguide or active waveguide.

5. An integrated ring resonator edge-emitting semiconductor laser as claimed in claim 1 wherein: and the converged light vertically output by the reflecting component is a monitoring port.

6. An integrated ring resonator edge-emitting semiconductor laser as claimed in claim 1 wherein: the reflection assembly comprises an inclined plane reflector which can correspond to the surface crystal direction of the wafer, and the inclined plane reflector is arranged at an outlet of the annular resonant cavity far away from the laser.

7. An integrated ring resonator edge-emitting semiconductor laser as claimed in claim 6 wherein: the reflecting surface of the inclined plane reflecting mirror is a smooth plane obtained by cutting and etching along the crystal face of the cubic crystal structure; or the reflecting surface of the inclined plane reflector is a curved surface.

8. An integrated ring resonator edge-emitting semiconductor laser as claimed in claim 7 wherein: and coating a film on the plane.

9. An integrated ring resonator edge-emitting semiconductor laser as claimed in claim 1 wherein: the number of the reflection assemblies is two, and the two reflection assemblies are symmetrically arranged by taking the diameter of the annular resonant cavity as a symmetry axis.

10. An integrated ring resonator edge-emitting semiconductor laser as claimed in claim 7 wherein: the cubic crystal structure is a band-gap InP and GaAs family and composites thereof, such as AlGaAs, InGaAsP, and AlGaInAs.

11. An integrated ring resonator edge-emitting semiconductor laser as claimed in claim 1 wherein: the reflecting components are arranged longitudinally or transversely, or arranged transversely and longitudinally simultaneously.

Technical Field

The invention relates to the technical field of lasers, in particular to an edge-emitting semiconductor laser integrated with a ring resonator.

Background

Semiconductor laser chips are core devices in optical communication systems, and with the increase of communication capacity requirements, semiconductor laser chips are rapidly developed. The bandwidth rate of a single semiconductor laser is limited, and the current mainstream is a single bandwidth of 10G to 25 GHz. As the bandwidth of semiconductor lasers has increased, the difficulty of design, process and testing has become greater.

First, semiconductor lasers typically have many side modes beyond the operating frequency due to their material gain characteristics; the side mode is possibly excited along with the change of the temperature, so that the conditions such as mode jumping and the like occur, and the performance of the laser during working is seriously influenced; thereby severely limiting or reducing the operating range or performance of commercial or industrial temperature laser chips over a wide operating temperature range. The existing laser does not additionally carry out effective suppression of side modes.

Secondly, Edge-Emitting lasers (EEL) are the mainstream of the conventional semiconductor lasers for communication. In the field of communications, there are a few markets for vertical cavity surface emitting lasers, but because of their relatively low output power, they are generally limited to short range and low speed applications. The vertical cavity laser has obvious advantages in production and test, and can be used for testing the whole wafer; i.e. before the post-processing (grinding/stripping/coating) the test can be performed. In contrast, the edge-emitting laser must pass through cumbersome post-processing steps and bar testing, which occupies significant man-hours; and the bars must be selected/loaded/tested/discharged and the like in a complicated way, so that time and labor are wasted, and certain yield loss is inevitable.

Disclosure of Invention

The invention aims to provide an edge-emitting semiconductor laser of an integrated ring resonator, which is characterized in that the filtering of side waves and the leading of light to other positions are realized through the integrated ring resonator, so that the spectral line of the laser is less interfered, the possibility of mode hopping of the laser is reduced, the signal output and the device performances such as the side mode suppression ratio of the laser are improved, and then part of light is led out to a vertical plane through a reflection assembly manufactured on a chip, so that a single chip has a traditional light-emitting surface and a vertical light-emitting position at the same time.

In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions: an edge-emitting semiconductor laser integrated with a ring resonator comprises an input port, a waveguide for guiding signals to the input port and a ring resonator for side lobe filtering, wherein the ring resonator is provided with four ports, two of the ports are overlapped with the waveguide, and at least one of the other two ports of the ring resonator is provided with a reflecting component capable of vertically outputting a light source.

Further, the relationship between the radius R of the ring resonator and the resonance order m thereof is:wherein

For its effective refractive index of the waveguide,

and adjusting the radius R and the resonance order m to realize a spectral line corresponding to the working wavelength of the laser.

Furthermore, the ring resonant cavity is also cascaded with a plurality of other ring resonant cavities.

Further, the ring-shaped resonant cavity adopts a passive waveguide or an active waveguide.

Further, the collected light vertically output by the reflection assembly is used as a monitoring port.

Further, the reflection assembly comprises an inclined plane reflector which can correspond to the crystal direction of the surface of the wafer, and the inclined plane reflector is arranged at an outlet of the annular resonant cavity, which is far away from the laser.

Further, the reflecting surface of the inclined surface reflecting mirror is a smooth plane obtained by cutting and etching along the crystal face of the cubic crystal structure; or the reflecting surface of the inclined plane reflector is a curved surface.

And further, coating a film on the plane.

Furthermore, the number of the reflection assemblies is two, and the two reflection assemblies are symmetrically arranged by taking the diameter of the annular resonant cavity as a symmetry axis.

Further, the cubic crystal structure is of the band-gap InP and GaAs series and composites thereof, such as AlGaAs, InGaAsP, and AlGaInAs.

Further, the reflecting component is arranged longitudinally or transversely, or transversely and longitudinally.

Compared with the prior art, the invention has the beneficial effects that: the utility model provides an edge-emitting semiconductor laser of integrated ring resonator, realizes the filtration of side wave through integrated ring resonator, and the light of derivation reaches other positions for the spectral line of laser instrument is less disturbed, reduces the possibility of laser instrument mode jump, thereby improves the device performances such as signal output and side mode rejection ratio of laser instrument, then through the reflection assembly of preparation on the chip, exports the perpendicular with some light, thereby realizes that single chip has traditional plain noodles and perpendicular light-emitting position simultaneously.

Drawings

Fig. 1 is a schematic diagram of an active waveguide of an edge-emitting semiconductor laser integrated with a ring resonator according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a passive waveguide of an edge-emitting semiconductor laser integrated with a ring resonator according to an embodiment of the present invention;

in the reference symbols: 1-a laser; 2-a ring resonator; 3-reflective component.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 and fig. 2, an embodiment of the present invention provides an edge-emitting semiconductor laser integrated with a ring resonator, including an input port, a waveguide for guiding a signal to the input port, and a ring resonator 2 for side lobe filtering, where the ring resonator 2 has four ports, two of the four ports are overlapped with the waveguide, and at least one of the other two ports of the ring resonator 2 is provided with a reflection component 3 capable of outputting a light source vertically. In the embodiment, the side lobe filtering is performed by integrating the ring-shaped resonant cavity 2 in the edge-emitting semiconductor laser 1, and light is guided out to other positions through four ports of the ring-shaped resonant cavity, so that the spectral line of the laser 1 is less interfered, the possibility of mode hopping of the laser 1 is reduced, the device performances such as signal output, edge mode rejection ratio and the like of the laser 1 are improved, then part of light is guided out to a vertical plane through the reflecting component 3, so that a single chip simultaneously has a traditional light-emitting surface and a vertical light-emitting position, and after the performance of the vertical-cavity surface-emitting laser is achieved, the test according to a whole wafer is realized on the premise of not influencing the chip performance of the laser 1 in the traditional scheme, so that the test steps are greatly simplified, the test time and the cost are reduced, and the laser 1 can be used as a traditional monolithic integrated semiconductor laser 1 chip, namely the edge-emitting laser, and can also be used as a surface-emitting laser for vertical packaging, thereby solving the problems that the conventional edge-emitting laser adopts the traditional test mode after strip decomposition and film coating, and the test can be carried out after the whole wafer is finished and then the strip decomposition and the strip film coating are carried out, if the yield of the single-chip multi-channel chip is low, the method not only takes the process procedure time before the wafer production, but also takes the post-process processing time, wastes more test time, and the test can only put the strip-separated single bar or even the strip-separated single chip into the test machine in turn, the time for taking and blanking is extremely delayed, therefore, the cost of mass production is increased, and many defects of partial devices may be damaged, and the whole wafer test can save more than half of the cost (packaging cost and testing time) and improve the yield of products. Preferably, the chip size is in the range of hundreds to thousands of microns, preferably 250 microns. The output signals of the lasers 1 are connected through waveguides and led to the input port, the ring-shaped resonant cavity 2 is provided with four ports, two ports are overlapped with the waveguides of the lasers 1, and the other two ports can output extra light. The ratio of the output optical power (to the power in the laser 1 waveguide) can be achieved by adjusting the distance of the ring oscillator from the laser 1. A reflecting component 3 is correspondingly manufactured at an outlet (which can be parallel or can change the direction through a curved waveguide) of the ring-shaped resonant cavity 2, which is far away from the laser 1; thereby realizing the vertical output of the light source of the edge-emitting semiconductor laser 1.

Referring to fig. 1 and fig. 2 as an optimized solution of the embodiment of the present invention, a relationship between a radius R of the ring resonator 2 and a resonance level m thereof is as follows:whereinFor its effective refractive index of the waveguide,the spectral line corresponding to the working wavelength of the laser 1 is realized by adjusting the radius R and the resonance order m. In this embodiment, the relationship between R and m can be adjusted according to the actual situation, so that the resonant level can be adjusted accordingly while the operating frequency of the device is kept unchanged, thereby providing a degree of freedom in design. According to the working principle and the coupling mode equation of the ring resonator 2, a reasonable radius is set to enable the high-order m-order spectral line of the ring resonator to work to correspond to the central frequency of the working wavelength of the laser 1, so that the side lobe filtering of the laser 1 is realized, and the spectral line of the laser 1 is less interfered. The size of the device is larger or smaller, the annular resonant cavity 2 can be larger or smaller, in addition, the degree of freedom corresponding to the resonance level can conveniently realize the spectral line corresponding to the working wavelength of the laser 1, and in the manufacturing process, the annular resonant cavity 2 can use standard spectral linesThe plane waveguide process has no complex requirement and has no strict requirement on the verticality of the side surface of the waveguide, and in performance, the size of the device of the ring resonant cavity 2 can be made small, so that the wavelength division multiplexer with narrower channels and more channels is realized. The free space of the chip can be easily found for layout, and more ring resonators 2 with the same or different radii can be cascaded to realize more spectrum shape control. More singlets can be produced on the same substrate, and the non-uniformity of the fabrication process will affect the device performance less than other wavelength division multiplexing of larger dimensions. High resolution performance is easier to realize, and the temperature control device is simpler. Whereas when the incident light contains multiple wavelengths (e.g., white light), only the resonant wavelength can pass completely through the ring resonator. The Quality Factor (Quality Factor, or Q-Factor) of an optical ring resonator can be quantitatively described using the following equation:

where F is the ring resonator accuracy, FSR is Free Spectral Range (FSR), and FWHM is the Full Width Half Maximum (FWHM) Spectrum width. The quality factor is useful for determining the spectral range of the resonance condition of any given ring resonator. The quality factor can also be used to quantify the amount of loss in the resonator, since low Q values are typically due to large losses. A particular resonance level m may be selected to achieve a desired specified operating wavelength. While the quality factor may be determined in terms of its free spectral range and full-width-half-maximum spectral width. The full width half maximum spectral width may be chosen to be sufficiently larger than the line width of the laser 1 itself and smaller than the distance between the modes on both sides. The proper annular resonant cavity 2 envelope can filter or limit side lobes and reduce the possibility of mode hopping of the laser 1, thereby improving the signal output of the laser 1, the side mode suppression ratio and other device performances. If the specified operating wavelength is fixed, the resonance level m may vary in general, and as shown in FIG. 2, the effective refractive index of the ring resonator may be such that the laser 1 electrode and the ring resonator may be fed using two different power supplies

Can be adjusted by the concentration of injected carriers, thereby realizing that the working wavelength of the corresponding laser 1 is fixed under the condition that the resonance level is not changed. The resonance level m corresponds directly to the Free Spectral Range (FSR) required by the device. The m-order and m + l-order diffraction of the resonance cannot overlap in the desired wavelength range. The wavelength which is different from the specified working wavelength by FSR, when the working wavelength is in the adjacent resonance level (namely m + l), the convergent point just coincides with the working port, and the formula shows that

The available Free Spectral Range (FSR) is:operating at a high order m with a smaller FSR, passing the effective refractive indexThe adjustment is matched to more conveniently align the operating wavelength of the laser 1.

Referring to fig. 1 and 2, as an optimized solution of the embodiment of the present invention, there are two reflection assemblies 3, and the two reflection assemblies 3 are symmetrically disposed with respect to a diameter of the ring resonator 2 as a symmetry axis. In conventional ring cavity 2 designs, light at the operating wavelength is lost through scattering and propagation in both ports away from the laser 1, but because there is no waveguide to receive. Therefore, in this embodiment, by reasonable design, the reflector is added at the corresponding position, so that extra laser output is obtained on the premise of not affecting the original edge emitting device, and the laser can be used as an extra monitoring working port of the primary emitting laser, can be used as a detection port for a vertical test, and can also be used as a vertical emitting laser. Considering that the mode and propagation direction of the laser 1 are related to the front and rear end coatings, for example, the front and rear end coatings of high reflection and high transmission are exchanged, the output port of the laser 1 is also exchanged front and rear. The ring cavity 2 has a symmetrical structure, so that the mode can automatically be compatible with clockwise resonance and anticlockwise resonance without any change. Therefore, when the laser 1 is adjusted to change the output port due to the coating selection, the ring resonator 2 is correspondingly arranged, and light can be output from the other corresponding port. Therefore, the position of the reflecting surface of the design is also made into a symmetrical design so as to be compatible with the vertical light emitting and also adapt to the vertical light emitting, and a corresponding port is selected.

Referring to fig. 1 and 2 as an optimized solution of the embodiment of the present invention, the ring resonator 2 is a passive waveguide or an active waveguide. In this embodiment, two schemes are provided, one scheme of which may use a passive state for the ring resonator 2, either using a passive waveguide (the process requires an active and passive regrowth process) or using an active material of the laser 1 without injecting current (some additional loss may be introduced), but the device bandwidth of this configuration is not affected, and for a high-speed device, the first scheme is preferably used, as shown in fig. 1. For the extra loss in the first scheme, the ring resonator 2 may be made of the same material as the laser 1 and connected to the electrode of the laser 1 to receive current, so that the waveguide of the ring resonator 2 has a gain amplification function and vertical output has higher power.

As an optimized solution of the embodiment of the present invention, the collected light vertically output by the reflection assembly 3 is a monitor port. In this embodiment, the device can be packaged and used as a conventional edge-emitting laser, but due to the additional light-emitting port in the vertical direction, an additional power monitoring port can be provided, so that the working condition and change of the laser chip can be better monitored in real time. In conventional solutions, this can only be achieved by backlight monitoring if this is to be achieved; additional space is required, coupling alignment requirements are high, packaging is complex and high cost. The additional vertical light emitting design of the design provides higher degree of freedom, monitoring is more convenient and simpler, and cost is lower.

Referring to fig. 1 and 2 as an optimized solution of the embodiment of the present invention, the reflection assembly 3 includes a tilted mirror capable of corresponding to a crystal direction of a surface of a wafer, and the tilted mirror is disposed at an exit of the ring resonator 2 away from the laser. The reflecting surface of the inclined plane reflecting mirror is a smooth plane obtained by cutting and etching along the crystal face of the cubic crystal structure; or the reflecting surface of the inclined surface reflector is an arc surface; or the reflecting surface of the inclined plane reflector is other curved surfaces. And coating a film on the plane. In this embodiment, the reflector may have both longitudinal and transverse structures, respectively aligned with crystal planes in different directions, facilitating process fabrication and providing freedom of choice. And because the waveguide connection behind the ring resonator 2 can use a curve, a slope mirror corresponding to any crystal plane direction can be manufactured in principle, and the slope mirror can be determined according to the type and the surface crystal direction of a specific wafer. The longitudinal and transverse bidirectional structures can be used simultaneously, and can also be made or only one selected according to the situation. The length of the bidirectional long-strip inclined plane reflector is as long as possible, and the manufacturing tolerance is guaranteed, so that the collected light is collected and used by moving a receiving optical waveguide or an optical fiber (which can be better focused through a prism) above the vertical plane. Outside the traditional input and output port, on the premise of not influencing the Edge Emitting Laser (EEL) function of the original structure, the vacant space of the chip is utilized to add the positions capable of receiving light with the same frequency, and the smooth crystal surfaces are manufactured in the areas to be used as reflectors, so that the combined wave Laser is simultaneously emitted to the direction vertical to the chip, the vertical Surface Emitting Laser (SEL) is realized, and the rapid test of the whole wafer level is allowed. Preferably, the cubic crystal structure is of the band-gap InP and GaAs families and composites thereof, such as AlGaAs, InGaAsP and AlGaInAs. These materials are crystalline structures, and when cut and etched along a crystal plane (e.g., wet etching), a very smooth plane is usually obtained, and thus they can be used as a reflective surface. The reflectivity of the mirror surface can be improved by plating (metal thin film) on the chip. Crystallographic planes and crystal orientations are generally defined in crystallography by the miller index. For a cubic crystal, two adjacent faces, labeled with miller indices [ h1k1l1] and [ h2k2l2], are determined by the following equation:

the available angles are all close to 45 degrees, for example, the crystal plane of the silicon crystal is more perfect than that of III-V materials such as InP, and the crystal plane of the quaternary mixture InGaAsP is about 52 degrees, so that the crystal plane can be directly used as the reflecting plane of the vertical light extraction design. The reflecting component 3, in which the inclined reflecting surface of the output port of the ring resonator is arranged longitudinally or transversely, or both, as shown in fig. 1 and 2, may be arranged transversely or longitudinally with respect to the position of the ring resonator 2, but in practice, it may not be arranged in both arrangements, and it is also possible to make the reflecting surface in any direction, as long as the light source can be output vertically. The vertical reflecting surface can be a plane or a curved surface, wherein the curved surface can be a cambered surface, and a plurality of reflecting assemblies can be arranged simultaneously in number without any limitation.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.