High power narrow linewidth hybrid integrated laser

Abstract

The application relates to the field of semiconductor lasers, in particular to a high-power narrow-linewidth hybrid integrated laser, which comprises a wide-waveguide laser gain chip and a silicon-based external cavity photonic chip, the silicon-based external cavity photonic chip comprising a tip multi-section edge coupler, a bus waveguide, at least three cascaded micro-ring resonators and a feedback component; the tip multi-section edge coupler comprises a tip waveguide array and a tapered combination waveguide, the tip waveguide array is composed of side-by-side inverted tapered waveguides, the width of the input end face of the inverted tapered waveguide is smaller than that of the output end face; and the width of the tapered combination waveguide gradually decreases from the input end to the output end. The application solves the industry problem that high power and narrow linewidth are difficult to be considered in a hybrid integrated laser, has the advantages of high output power, extremely narrow linewidth, wide tuning range, high coupling efficiency, good process tolerance and high integration, and provides a high-performance light source for the next-generation coherent optical communication, laser radar and precision measurement system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor lasers, and particularly relates to a high-power narrow-linewidth hybrid integrated laser. BACKGROUND

[0002] The hybrid integration of III-V active laser gain chips and silicon-based external cavity photonic chips provides a promising technical path for realizing narrow-linewidth lasers, optical frequency combs, optical interconnections, and photonic computing, etc. of high-performance III-V active photonic integrated circuits (PICs). Active PICs are widely used in coherent optical communication, laser radar, precision measurement, and microwave photonics, etc. In these applications, in order to support long-distance transmission and detection, overcome high link loss, improve signal-to-noise ratio (SNR), and realize strong nonlinear optical effects, the demand for high-power, narrow-linewidth lasers is increasing, and the necessary laser output power varies from tens of milliwatts to several watts, and the linewidth requirement varies from hundreds of kHz to Hz level.

[0003] However, there is a significant mismatch between the mode field distributions of III-V active laser gain chips and silicon-based external cavity photonic chips, resulting in large end-coupling loss. In the prior art, by using edge couplers with inverted taper structures, Y-shaped tip structures, or trident structures, the optical power of single-mode or small-mode-field-diameter laser chips can be effectively coupled into silicon-based external cavity photonic chips. However, these edge couplers are suitable for laser chips with small mode fields, and cannot meet the demand for high power.

[0004] In order to increase the output power, wide-waveguide laser gain chips (such as wide stripe chips or tapered amplification structures) are introduced, which have larger mode field sizes, but this also leads to a more severe mismatch between the mode fields of the silicon-based photonic chips, and further reduces the coupling efficiency. Traditional wide-taper edge couplers attempt to solve this problem, but due to the limitation of the thickness of the silicon-based waveguide, the matching degree of the coupling end face mode field and the spot mode field of the wide-waveguide laser chip is still not high, and the light transmission in the wide-waveguide is prone to modal disturbance and diffraction effects, usually requiring a longer coupler length (such as more than 1500 μm), which increases the complexity and cost of manufacturing and packaging.

[0005] In terms of external cavity design, the existing hybrid integrated lasers often use silicon-based photonic chips with cascaded double-micro-ring resonators integrated Sagnac ring reflectors to narrow the laser linewidth to the kHz level. However, the effective cavity length of this scheme is limited, and it is difficult to further narrow the linewidth, and the feedback light of the Sagnac ring reflector needs to pass through the micro-ring resonator, resulting in large loss of feedback light power, making it difficult to achieve strong feedback while maintaining high output power. SUMMARY

[0006] In view of the above, the present application aims to provide a high-power narrow linewidth hybrid integrated laser to solve the technical problems of the prior art in efficient coupling of high-power wide waveguide laser chips and silicon-based photonic chips, and linewidth narrowing of long effective cavity length and high feedback utilization rate.

[0007] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0008] A high-power narrow linewidth hybrid integrated laser comprises:

[0009] A wide waveguide laser gain chip for providing optical gain;

[0010] A silicon-based external cavity photonic chip coupled with the wide waveguide laser gain chip for forming a laser resonant cavity and providing optical feedback; wherein the silicon-based external cavity photonic chip comprises:

[0011] A tip multi-section edge coupler with an input end butting against an output end of the wide waveguide laser gain chip for receiving and coupling optical signals;

[0012] A bus waveguide connected with an output end of the tip multi-section edge coupler for realizing transmission of optical signals;

[0013] At least three cascaded micro-ring resonators coupled with the bus waveguide for mode selection and expansion of the effective cavity length of the silicon-based external cavity photonic chip;

[0014] A feedback component arranged on one side of the output end of the bus waveguide for feeding back part of the output light of the cascaded micro-ring resonators to the bus waveguide and transmitting to the wide waveguide laser gain chip;

[0015] The tip multi-section edge coupler comprises:

[0016] A tip waveguide array composed of side-by-side arranged inverted cone waveguides with the width of the input end face smaller than that of the output end face for butt joint with the output end of the wide waveguide laser gain chip and improving the end face coupling efficiency between the spot mode field of the wide waveguide laser gain chip and the tip waveguide array;

[0017] A tapered combination waveguide with the width gradually decreasing from the input end to the output end, the input end of the tapered combination waveguide connected with the output end of the tip waveguide array, and the output end of the tapered combination waveguide connected with the bus waveguide, the tapered combination waveguide for compressing the spot mode field of the wide waveguide laser gain chip into a single mode and transmitting to the bus waveguide.

[0018] Further, the inverted taper waveguides in the array of inverted taper waveguides are arranged equidistantly side by side, and the length, the width of the input end face and the width of the output end face of each inverted taper waveguide are the same.

[0019] Further, the number of the inverted taper waveguides is 62, the length of each inverted taper waveguide is 40 μm, the width of the input end face of each inverted taper waveguide is 0.26 μm, the width of the output end face of each inverted taper waveguide is 0.5 μm, and the center distance between two adjacent inverted taper waveguides is 0.8 μm.

[0020] Further, the tapered combined waveguide is composed of tapered waveguides connected head to tail, and the width of each tapered waveguide gradually decreases from the input end to the output end.

[0021] Further, the tapered combined waveguide is composed of three tapered waveguides connected head to tail, the width of the input end face of the first tapered waveguide is greater than the width of the output end face, the width of the input end face of the second tapered waveguide is the same as the width of the output end face of the first tapered waveguide and the width of the input end face of the second tapered waveguide is greater than the width of the output end face, and the width of the input end face of the third tapered waveguide is the same as the width of the output end face of the second tapered waveguide and the width of the input end face of the third tapered waveguide is greater than the width of the output end face.

[0022] Further, the length of the first tapered waveguide is 350 μm, the width of the input end face of the first tapered waveguide is 50 μm, and the width of the output end face of the first tapered waveguide is 30 μm; the length of the second tapered waveguide is 200 μm, the width of the input end face of the second tapered waveguide is 30 μm, and the width of the output end face of the second tapered waveguide is 15 μm; the length of the third tapered waveguide is 60 μm, the width of the input end face of the third tapered waveguide is 15 μm, and the width of the output end face of the third tapered waveguide is 1 μm.

[0023] Further, the number of the cascaded micro-ring resonators is 3, the difference between the radii of the first micro-ring resonator and the second micro-ring resonator is a first difference value, the radius of the third micro-ring resonator is greater than the radii of the first micro-ring resonator and the second micro-ring resonator, and the difference between the radius of the third micro-ring resonator and the radius of the first micro-ring resonator or the second micro-ring resonator is a second difference value, and the second difference value is greater than the first difference value.

[0024] Further, the wide waveguide laser gain chip is a multi-mode wide straight waveguide structure or a tapered amplification waveguide structure.

[0025] Further, the feedback assembly comprises:

[0026] a coupling waveguide, the coupling waveguide is arranged in parallel with the output end of the cascaded micro-ring resonator, and the light output by the cascaded micro-ring resonator is coupled into the input end of the coupling waveguide;

[0027] The feedback waveguide is connected with the output end of the coupling waveguide and the input end of the bus waveguide, and is used for feeding back the part of the output light coupled out from the coupling waveguide to the wide waveguide laser gain chip through the bus waveguide.

[0028] Further, the silicon-based external cavity photonic chip comprises a silicon substrate layer and, sequentially deposited on the silicon substrate layer from bottom to top, a silicon dioxide lower cladding layer, a silicon nitride waveguide layer and a silicon dioxide upper cladding layer, a tip multi-section edge coupler, a bus waveguide and cascaded micro-ring resonators are respectively prepared on the silicon nitride waveguide layer, and heating electrodes for phase modulation are deposited on the silicon dioxide upper cladding layer at positions corresponding to the bus waveguide and the cascaded micro-ring resonators.

[0029] Compared with the prior art, the application can achieve the following beneficial effects:

[0030] 1. The wide waveguide laser gain chip is used as a gain medium in the application, which can provide higher output power compared with traditional single-mode or small-mode-size laser chips.

[0031] 2. The tip multi-section edge coupler designed in the application expands the vertical mode field through a tip waveguide array, significantly improving the end coupling efficiency between the wide waveguide laser gain chip and the silicon-based external cavity photonic chip.

[0032] 3. The tip multi-section edge coupler also has excellent broadband performance, covering the long-wave part of the O band to the L band with a coupling loss of less than 1 dB.

[0033] 4. Compared with traditional wide taper edge couplers, the length of the coupler is optimized to 650 μm through a three-stage taper combination structure, significantly shortening the coupler length, reducing modal disturbance and diffraction effects.

[0034] 5、The application adopts three cascaded different radius micro-ring resonator to design a photonic external cavity chip, wherein the radius of the third micro-ring resonator is much larger than that of the first two micro-ring resonators, which greatly increases the effective cavity length of the external cavity. The feedback waveguide designed in combination with the coupling mode theory maximizes the utilization of feedback optical power, further narrows the laser linewidth, and realizes a linewidth of kHz or even narrower.

[0035] 6、The three cascaded micro-ring resonators realize a wider wavelength tuning range through the vernier effect, and compared with the traditional double micro-ring resonator structure, the tuning range is wider. In combination with the thermal phase tuning function of the heating electrode, fast and fine wavelength tuning can be realized, which meets the needs of various application scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0036] The drawings constituting a part of this application provide further understanding of the application, the illustrative embodiments of the application and the description thereof serve to explain the application, and do not constitute an improper limitation on the application. In the drawings:

[0037] Figure 1 Structure schematic view of the high-power narrow-linewidth hybrid integrated laser described in the embodiments of the application;

[0038] Figure 2 Structure schematic view of the tip multi-section edge coupler described in the embodiments of the application;

[0039] Figure 3 Fundamental mode light spot mode field distribution schematic view of the wide waveguide laser gain chip described in the embodiments of the application;

[0040] Figure 4 Mode field distribution schematic view of the tip waveguide array described in the embodiments of the application; wherein,

[0041] Figure 4 (a) in FIG. 1 shows the mode field distribution of a single inverted taper waveguide incident end face;

[0042] Figure 4 (b) in FIG. 1 shows the mode field distribution after coupling of all inverted taper waveguide incident end faces;

[0043] Figure 5 Length of each section of the tip four-section edge coupler and simulation result graph of the influence of the length of each section of the tip four-section edge coupler on the total coupling efficiency between the wide waveguide laser gain chip and the tip four-section edge coupler described in the embodiments of the application; wherein,

[0044] Figure 5 (a) in FIG. 2 shows the relationship between the length L1 of the tip waveguide array and the total coupling efficiency;

[0045] Figure 5(b) of FIG. 1 shows the relationship between the first segment of the tapered waveguide length L2 and the total coupling efficiency;

[0046] Figure 5 (c) of FIG. 1 shows the relationship between the second segment of the tapered waveguide length L3 and the total coupling efficiency;

[0047] Figure 5 (d) of FIG. 1 shows the relationship between the third segment of the tapered waveguide length L4 and the total coupling efficiency;

[0048] Figure 6 FIG. 2 shows the mode evolution of the optical field described in the embodiments of the present application when transmitted in a 650 μιη long tip four-segment edge coupler; wherein,

[0049] Figure 6 (a) of FIG. 2 shows the optical field distribution in the Y-Z plane at the start position (x = 0 μιη) of the tip four-segment edge coupler;

[0050] Figure 6 (b) of FIG. 2 shows the optical field distribution in the Y-Z plane at a distance of 41 μιη from the start position (x = 41 μιη) in the tip four-segment edge coupler;

[0051] Figure 6 (c) of FIG. 2 shows the optical field distribution in the Y-Z plane at a distance of 215 μιη from the start position (x = 215 μιη) in the tip four-segment edge coupler;

[0052] Figure 6 (d) of FIG. 2 shows the optical field distribution in the Y-Z plane at a distance of 390 μιη from the start position (x = 390 μιη) in the tip four-segment edge coupler;

[0053] Figure 6 (e) of FIG. 2 shows the optical field distribution in the Y-Z plane at a distance of 490 μιη from the start position (x = 490 μιη) in the tip four-segment edge coupler;

[0054] Figure 6 (f) of FIG. 2 shows the optical field distribution in the Y-Z plane at a distance of 590 μιη from the start position (x = 590 μιη) in the tip four-segment edge coupler;

[0055] Figure 6 (g) of FIG. 2 shows the optical field distribution in the Y-Z plane at a distance of 620 μιη from the start position (x = 620 μιη) in the tip four-segment edge coupler;

[0056] Figure 6(h) in the above-mentioned (g) shows the light field distribution in the Y-Z plane at a distance of 650 microns from the starting position (x = 650 pm) in the tip four-section edge coupler;

[0057] Figure 7 A schematic diagram of the total coupling efficiency versus wavelength between the wide waveguide laser gain chip and the 650 pm long tip four-section edge coupler described in the embodiments of the present invention.

[0058] Legend: wide waveguide laser gain chip 1, silicon-based external cavity photonic chip 2, tip multi-section edge coupler 21, bus waveguide 22, first micro-ring resonator 23, second micro-ring resonator 24, third micro-ring resonator 25, coupling waveguide 26, feedback waveguide 27. DETAILED DESCRIPTION

[0059] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, and do not constitute a limitation on the present invention.

[0060] It should be noted that the embodiments in the present invention and the features in the embodiments can be combined with each other without conflict.

[0061] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present invention and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second" and the like are only used for description purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0062] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "assembly", "connection", "linkage" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0063] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0064] As Figure 1 shown, the embodiment of the present application provides a high-power narrow linewidth hybrid integrated laser, which comprises a wide waveguide laser gain chip 1 and a silicon-based external cavity photonic chip 2. The wide waveguide laser gain chip 1 is used to provide optical gain. The silicon-based external cavity photonic chip 2 is coupled with the wide waveguide laser gain chip 1, and is used to form a laser resonant cavity and provide optical feedback.

[0065] In order to realize higher output power of the hybrid integrated laser, the present application adopts a wide waveguide laser gain chip 1 to provide gain for the hybrid integrated laser. The wide waveguide laser gain chip 1 adopts a multimode wide straight waveguide structure or a tapered amplification waveguide structure, has very high optical gain, and has a large spot mode field, such as above 40 μm / 50 μm. The center wavelength of the wide waveguide gain chip 1 can be any waveband, such as 1310 nm waveband, 1060 nm waveband, 1550 nm waveband. The end of the wide waveguide laser gain chip 1 facing the silicon-based external cavity photonic chip 2 is coated with a high reflection film, and the end of the wide waveguide laser gain chip 1 facing the silicon-based external cavity photonic chip 2 is coated with an anti-reflection film.

[0066] The silicon-based external cavity photonic chip 2 comprises a silicon substrate layer and, deposited on the silicon substrate layer from bottom to top, a silicon dioxide lower cladding layer, a silicon nitride waveguide layer and a silicon dioxide upper cladding layer. A sharp multi-section edge coupler 21, a bus waveguide 22, at least three cascaded micro-ring resonators and a feedback component are prepared on the silicon nitride waveguide layer. The input end of the sharp multi-section edge coupler 21 is butted with the output end of the wide waveguide laser gain chip, and is used to receive and couple optical signals. The bus waveguide 22 is connected with the output end of the sharp multi-section edge coupler 21, and is used to realize transmission of optical signals. The cascaded micro-ring resonators are coupled with the bus waveguide 22, and are used to select mode and expand the effective cavity length of the silicon-based external cavity photonic chip 2. The feedback component is arranged on one side of the output end of the bus waveguide 22, and is used to feedback part of the output light of the cascaded micro-ring resonators back to the bus waveguide 22, and transmit to the wide waveguide laser gain chip 1.

[0067] Due to the silicon nitride material has low optical loss, high nonlinear coefficient, wide transparent window and excellent light field constraint ability, a silicon-based external cavity photonic chip 2 is designed by using the silicon nitride waveguide.

[0068] Since the mode field of the wide waveguide laser gain chip 1 is much larger than the mode field of the single-mode silicon nitride waveguide, the efficiency of direct coupling between the two is extremely low, so a new type of tip multi-section edge coupler 21 is designed to realize the coupling between the wide waveguide laser gain chip 1 and the silicon-based external cavity photonic chip 2. The coupling end of the tip multi-section edge coupler 21 expands the vertical mode field by using a tip waveguide array, thereby improving the end coupling efficiency with the wide waveguide laser gain chip 1. The transmission zone of the tip multi-section edge coupler 21 adopts a tapered combined waveguide with gradually decreasing width, which greatly shortens the length of the tip multi-section edge coupler 21, thereby suppressing mode disturbance and diffraction effect, and further reducing the transmission loss of the tip multi-section edge coupler 21. This design can make the tip multi-section edge coupler 21 realize higher coupling efficiency in a shorter length. Therefore, the tip multi-section edge coupler 21 can efficiently couple the wide waveguide laser gain chip 1 and the silicon-based external cavity photonic chip 2 together, and finally realize high-power output of the hybrid integrated laser.

[0069] The silicon-based external cavity photonic chip 2 is designed by using a plurality of cascaded micro-ring resonators with different radii, wherein the radius of the micro-ring resonator gradually increases, and the radius of the last micro-ring resonator is much larger than the radius of the other micro-ring resonators, which greatly increases the effective cavity length of the external cavity. The plurality of cascaded micro-ring resonators are used as filters to select the mode for the hybrid integrated laser, and provide a longer effective cavity length to narrow the laser linewidth. At the same time, due to the different radii of the plurality of micro-ring resonators, the vernier effect generated can enable the hybrid integrated laser to achieve a wider tuning range. Figure 1 As shown in FIG. 3, three micro-ring resonators are shown, the radius of the second micro-ring resonator 24 is slightly larger than the radius of the first micro-ring resonator 23, the radius of the first micro-ring resonator 23 and the second micro-ring resonator 24 is very small, and the radius of the third micro-ring resonator 25 is much larger than the radius of the second micro-ring resonator 24 and the first micro-ring resonator 23, which greatly expands the effective cavity length of the external cavity photonic chip, and further narrows the laser linewidth. The reason for selecting three cascaded micro-ring resonators in the present application is that the vernier effect of the three cascaded micro-ring resonators can obtain a larger wavelength tuning range than two cascaded micro-ring resonators.

[0070] The present application designs a feedback component based on the coupled mode theory, which comprises a coupling waveguide 26 and a feedback waveguide 27. The coupling waveguide 26 is composed of a straight waveguide, and is arranged in parallel with the output end of the cascaded micro-ring resonator. The light output by the cascaded micro-ring resonator is coupled into the coupling waveguide 26 from the input end of the coupling waveguide. The input end of the feedback waveguide 27 is connected with the output end of the coupling waveguide 26, and the output end of the feedback waveguide 27 is connected with the bus waveguide 22. The feedback waveguide 27 is used to feed back the part of the output light coupled out by the coupling waveguide 26 to the wide waveguide laser gain chip 1 through the bus waveguide 22, which maximizes the power of the feedback light. The longer external cavity effective cavity length and the stronger feedback effect can further narrow the linewidth of the laser.

[0071] The heating electrodes for phase modulation are deposited on the cladding corresponding to the positions of the bus waveguide 22 and the cascaded micro-ring resonator on the silicon dioxide. The phase of the bus waveguide 22 and the cascaded micro-ring resonator is controlled by thermal tuning, which can achieve faster and more precise wavelength tuning.

[0072] The tip multi-section edge coupler 21 comprises a tip waveguide array and a tapered combination waveguide. The tip waveguide array is composed of a plurality of inverted tapered waveguides arranged side by side. The input end face of the inverted tapered waveguide has a smaller width than the output end face, which is used to butt joint with the output end of the wide waveguide laser gain chip 1 and improve the end face coupling efficiency between the spot mode field of the wide waveguide laser gain chip 1 and the tip waveguide array. The tapered combination waveguide is composed of tapered waveguides connected in head-to-tail. The width of each section of the tapered waveguide gradually decreases from the input end to the output end. The overall width of the tapered combination waveguide gradually decreases from the input end to the output end. The input end of the tapered combination waveguide is connected with the output end of the tip waveguide array, and the output end of the tapered combination waveguide is connected with the bus waveguide 22. The tapered combination waveguide is used to compress the spot mode field of the wide waveguide laser gain chip 1 into a single mode and transmit it to the bus waveguide 22.

[0073] Each inverted tapered waveguide has a tiny mode field. The tip waveguide array combines a larger effective mode field in the vertical direction through the spatial superposition of the tiny mode fields of the inverted tapered waveguides, so as to match the spot mode field distribution of the wide waveguide laser gain chip 1, increase the mode overlap efficiency with the wide waveguide laser gain chip 1, and further improve the end face coupling efficiency between the mode field of the wide waveguide laser gain chip 1 and the tip waveguide array. If the tip waveguide array is cancelled and only the tapered combination waveguide is reserved, the vertical direction mode field of the tip multi-section edge coupler 21 is limited by the waveguide thickness, which cannot expand the vertical direction mode field, so as to reduce the mode overlap efficiency between the tip multi-section edge coupler 21 and the wide waveguide laser gain chip 1, and further cause the coupling efficiency to decrease, which is difficult to improve the coupling efficiency.

[0074] Multiple inverted conical waveguides are arranged at equal intervals, and each inverted conical waveguide has the same length, input end-face width, and output end-face width. The number of inverted conical waveguides, their lengths, the widths of their input end-faces, and the center-to-center spacing between adjacent inverted conical waveguides mainly affect the mode overlap efficiency with the wide-waveguide laser gain chip 1. A higher mode overlap efficiency indicates a higher end-face coupling efficiency between the tip multi-segment edge coupler 21 and the wide-waveguide laser gain chip 1, meaning more light is coupled from the wide-waveguide laser gain chip 1 into the tip multi-segment edge coupler 21. In practical applications, based on the different mode field dimensions of the wide waveguide laser gain chip 1, the number of inverted conical waveguides, the length of the inverted conical waveguides, the width of the input end face of the inverted conical waveguides, and the center spacing between two adjacent inverted conical waveguides can be determined by simulation using the FDE and FDTD modules in the Lumerical simulation software. The goal is to achieve the maximum mode overlap efficiency (i.e., end face coupling efficiency) between the tip multi-segment edge coupler 21 and the wide waveguide laser gain chip 1.

[0075] The width of the rear face of the inverted conical waveguide, the length of the conical composite waveguide, and the widths at both ends of the conical composite waveguide primarily affect the transmission efficiency of the tip multi-segment edge coupler 21, and consequently, its overall coupling efficiency. In practical applications, these factors can be determined through simulation using the EME and FDTD modules in Lumerical simulation software, with the goal of maximizing the overall coupling efficiency of the tip multi-segment edge coupler 21.

[0076] The following explanation uses a four-segment tip-type edge coupler as an example. A tip waveguide array is used as the first segment of the edge coupler, and three tapered waveguide segments are used as the second to fourth segments.

[0077] like Figure 2 As shown, I is a pointed waveguide array with a length of L1; pointed waveguide array I consists of a row of equally spaced inverted conical waveguides, W a W is the width of the incident end face of each inverted conical waveguide. b The width of the exit face of each inverted conical waveguide is W, and the width of the incident face of the inverted conical waveguide is W. a smaller than the width W of the exit end face b W c N is the center-to-center distance between two adjacent inverted conical waveguides. tip The number of inverted conical waveguides. These parameters of the aforementioned tip waveguide array depend on the beam pattern size of the wide waveguide laser gain chip 1.

[0078] The three-section tapered combined waveguide is composed of three first-section tapered waveguide II, second-section tapered waveguide III and third-section tapered waveguide IV connected in sequence, the length of the first-section tapered waveguide II is L2, the length of the second-section tapered waveguide III is L3, and the length of the third-section tapered waveguide IV is L4. The first-section tapered waveguide II is connected with the tip waveguide array I, the width of the incident end face of the first-section tapered waveguide II is W1, and the width of the outgoing end face of the first-section tapered waveguide II is W2. The second-section tapered waveguide III is used to connect the first-section tapered waveguide II and the third-section tapered waveguide IV, the width of the incident end face of the second-section tapered waveguide III is W2, and the width of the outgoing end face of the second-section tapered waveguide III is W3. The outgoing end of the third-section tapered waveguide IV is connected with the bus waveguide 22, the width of the incident end face of the third-section tapered waveguide IV is W3, and the width of the outgoing end face of the third-section tapered waveguide IV is W4.

[0079] The center distance W between the adjacent inverted tapered waveguides is fixed c , by optimizing the number and width of the inverted tapered waveguide through simulation, the mode overlap efficiency between the tip four-section edge coupler and the wide waveguide laser gain chip 1 can be increased, and then the end face coupling efficiency between the two can be improved. By optimizing the length of the tip waveguide array I, the first-section tapered waveguide II, the second-section tapered waveguide III and the third-section tapered waveguide IV through simulation, the transmission loss of light in the tip four-section edge coupler can be reduced, and then the total coupling efficiency of the tip four-section edge coupler can be increased.

[0080] The simulation verification of the tip four-section edge coupler is as follows:

[0081] As shown in Figure 3 , the fundamental mode light spot mode field diameter of the wide waveguide laser gain chip 1 is about 50μm (Y-axis direction, i.e. horizontal direction of the light field) x 2.5μm (Z-axis direction, i.e. vertical direction of the light field).

[0082] The structure parameters of the inverted tapered waveguide are determined by using the FDE module and the FDTD module in the Lumerical simulation software according to the wide waveguide laser gain chip 1 with the fundamental mode light spot mode field diameter of about 50μm x 2.5μm: the width W a of the incident end face of the inverted tapered waveguide and the width W b of the outgoing end face are 0.26μm and 0.5μm respectively, the center distance W c between the inverted tapered waveguides is 0.8μm, and the number of the inverted tapered waveguides is 62. At this time, the end face coupling efficiency between the wide waveguide laser gain chip 1 and the tip four-section edge coupler is about 0.92. The mode field distribution of the incident end face of a single inverted tapered waveguide and the mode field distribution after coupling of all the incident end faces of the inverted tapered waveguides are shown in (a) and (b) of Figure 4 , respectively, Figure 4(b) shows the optical field morphology of the entire coupling end face composed of all 62 inverted conical waveguides. The shape and size of this synthesized optical field match the large spot mode field of 50μm×2.5μm output by the wide waveguide laser gain chip 1.

[0083] After selecting W1, W2, W3, and W4 as 50μm, 30μm, 15μm, and 1μm respectively, this invention used the EME module in Lumerical software to simulate the influence of the length of each segment of the tip-type four-segment edge coupler on the overall coupling efficiency between the wide waveguide laser gain chip 1 and the tip-type four-segment edge coupler. The results are as follows: Figure 5 As shown in (a)-(d) in the figure. Based on the simulation results, the final selected lengths are: L1 of the tip waveguide array is 40 μm, L2 of the first tapered waveguide segment is 350 μm, L3 of the second tapered waveguide segment is 200 μm, and L4 of the third tapered waveguide segment is 60 μm. The total length of the corresponding four-segment tip edge coupler is 650 μm, and its total coupling efficiency is approximately 0.88.

[0084] Traditional edge couplers based on a single wide tapered waveguide require increasing their length (generally above 1500 μm) to reduce transmission loss by suppressing mode perturbations and diffraction effects, in order to ensure high coupling efficiency. This invention optimizes the overall length of the four-segment tip edge coupler to 650 μm through a three-segment tapered waveguide design, which can suppress mode perturbations and diffraction effects, thereby reducing the transmission loss of the edge coupler. This design enables the edge coupler to achieve higher coupling efficiency with a shorter length.

[0085] This invention illustrates the evolution of the beam pattern field when the light field propagates in a 650 μm long tip-four-segment edge coupler, such as... Figure 6 As shown in (a)-(h).

[0086] For the starting position: such as Figure 6 As shown in (a), x=0μm corresponds to the incident end face position of the light field at the tip waveguide array, showing a broadened mode field that matches the large-size light spot of the wide waveguide laser gain chip 1, thus achieving high end face coupling efficiency.

[0087] For intermediate processes: such as Figure 6 As shown in (b) to (g), light propagates in a three-segment tapered waveguide. Figure 6 Figures (b) to (g) clearly demonstrate how the optical field is gradually constrained and compressed without significant mode distortion or scattering. This directly proves the effectiveness of the present invention in suppressing mode perturbations and diffraction effects, and is key to achieving high transmission efficiency in the tip-type four-segment edge coupler.

[0088] For the end position: as shown in (h) in FIG. 6, x = 650 pm corresponds to the light field being perfectly compressed into a small, well-defined spot, which matches the fundamental mode of the bus waveguide 22, indicating that the light field is ready to be efficiently launched into the subsequent photonic circuit. Figure 6

[0089] Further, the present application simulates the dependence of the total coupling efficiency on wavelength between the wide waveguide laser gain chip 1 and the 650 pm long tip four-stage edge coupler by FDTD module in Lumerical software, and the result is shown in FIG. 7. The tip four-stage edge coupler shows an ultra-wideband performance with less than 1 dB coupling loss from O-band long wave to L-band, and the horizontal alignment tolerance of 1 dB extra loss is up to ±8.5 pm. The simulation result shows that the coupling efficiency of the tip four-stage edge coupler at the wavelength of 1550 nm of the wide waveguide laser chip 1 is as high as 88%, and the corresponding coupling loss is only 0.56 dB. The coupling performance is comparable to the performance of edge couplers designed for single-mode or small-mode field size laser chips. Figure 7

[0090] It should be understood that the various forms of flow shown above can be reordered, added to, or deleted from without departing from the scope of the present application. For example, the steps recited in the present disclosure can be performed in parallel, in series, or in a different order, without departing from the desired results of the technical solutions disclosed in the present disclosure, and the present disclosure is not limited herein.

[0091] The above detailed description does not constitute a limitation on the protection scope of the present application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.​​​

Claims

1. A high power narrow linewidth hybrid integrated laser, characterized in that, The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback.

2. The high power narrow linewidth hybrid integrated laser of claim 1, wherein, The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback.

3. The high power narrow linewidth hybrid integrated laser of claim 1, wherein, The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback.

4. The high power narrow linewidth hybrid integrated laser of claim 1, wherein, The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback.

5. The high power narrow linewidth hybrid integrated laser of claim 4, wherein, The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled with wide waveguide laser gain chip, to form laser resonant cavity and provide optical feedback. The utility model relates to a kind of silicon-based external cavity photonic chip and wide waveguide laser gain chip, and the silicon-based external cavity photonic chip is coupled 6. The high power narrow linewidth hybrid integrated laser of claim 5, wherein, The first taper waveguide has a length of 350 mu m, a width of 50 mu m at an input end, and a width of 30 mu m at an output end; the second taper waveguide has a length of 200 mu m, a width of 30 mu m at an input end, and a width of 15 mu m at an output end; and the third taper waveguide has a length of 60 mu m, a width of 15 mu m at an input end, and a width of 1 mu m at an output end.

7. The high power narrow linewidth hybrid integrated laser of claim 1, wherein, The number of the cascaded micro-ring resonators is three, the difference between the radii of the first micro-ring resonator and the second micro-ring resonator is a first difference value, the radius of the third micro-ring resonator is greater than the radii of the first micro-ring resonator and the second micro-ring resonator, and the difference between the radius of the third micro-ring resonator and the radius of the first micro-ring resonator or the second micro-ring resonator is a second difference value, the second difference value being greater than the first difference value.

8. The high power narrow linewidth hybrid integrated laser of claim 1, wherein, The wide waveguide laser gain chip is a multimode wide straight waveguide structure or a tapered amplification waveguide structure.

9. The high power narrow linewidth hybrid integrated laser of claim 1, wherein, The feedback assembly comprises: a coupling waveguide, which is arranged in parallel with an output end of the cascaded micro-ring resonators, and light output by the cascaded micro-ring resonators is coupled into an input end of the coupling waveguide; a feedback waveguide, an input end of the feedback waveguide being connected with an output end of the coupling waveguide, and an output end of the feedback waveguide being connected with the bus waveguide, the feedback waveguide being used for feeding back, through the bus waveguide, part of the light output by the coupling waveguide to the wide waveguide laser gain chip.

10. The high power narrow linewidth hybrid integrated laser of claim 1, wherein, The silicon-based external cavity photonic chip comprises a silicon substrate layer, a silicon dioxide lower cladding layer, a silicon nitride waveguide layer and a silicon dioxide upper cladding layer deposited on the silicon substrate layer from bottom to top, and a tip multi-section edge coupler, a bus waveguide, cascaded micro-ring resonators and a feedback assembly are respectively prepared on the silicon nitride waveguide layer, and heating electrodes for phase modulation are deposited on the silicon dioxide upper cladding layer at positions corresponding to the bus waveguide and the cascaded micro-ring resonators.

Images