High-power narrow-linewidth widely tunable lasers integrated with multi-material systems

Abstract

The present invention relates to the field of semiconductor laser technology, and in particular to a high-power narrow-linewidth wide-range tunable laser integrated with a multi-material system, comprising a silicon substrate and a silicon dioxide buried oxide layer arranged on the silicon substrate, and also comprising a III-V group gain chip, a mode converter, a tunable Sagnac ring connected to the III-V group gain chip composed of a silicon waveguide, and a three-microring resonator connected to the mode converter composed of a lithium niobate / silicon nitride composite, wherein the three-microring resonator in series and the tunable Sagnac ring form an equivalent resonant cavity. The high-power narrow-linewidth wide-range tunable laser integrated with a multi-material system prepared by the present invention can meet the urgent needs of the next generation of ultra-high-speed coherent optical communication for multi-band large-capacity transmission and the narrow-linewidth tunable laser for the frequency-modulated continuous wave optical phased array laser radar based on the next generation of ultra-high-speed coherent optical communication.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor lasers, and in particular relates to a high-power narrow-linewidth wide-range tunable laser integrated with a multi-material system. Background Art

[0002] With the rapid development of optical communication technology, higher requirements are placed on the spectral tuning range and linewidth characteristics of semiconductor lasers. In the future, 6G network applications will further focus on 3D immersive experience, including new applications such as extended reality, intelligent interaction, holographic communication, and digital twins. The rise of these new applications will place higher requirements on network bandwidth, latency, and reliability. In addition, with the upgrade and expansion of backbone networks (over 1,000 km) and metropolitan area networks (100-1,000 km), as well as the increasing demand for large bandwidth and long-distance optical interconnection (80-120 km) in distributed data centers, operators are in urgent need of maximizing spectrum and cost efficiency. Operators hope to increase rate capacity, continue to reduce per-bit costs, and minimize the physical space occupied by equipment while maintaining the same transmission distance. However, existing lasers used in coherent optical communications are limited by key performance indicators such as power, linewidth, and tuning range, and can no longer meet the needs of future medium- and long-distance ultra-high-speed coherent optical communications. From the perspective of coherent optical communication transmission technology, by expanding the baud rate and modulation code order, the single-wave rate can be effectively improved, and increasing the number of parallel channels can further increase the information transmission capacity. For example, in the 100G-QPSK era, 80 waves only require a 32Gbaud baud rate and a 4THz bandwidth in the C band, but after entering the 400G-QPSK era, it needs to be expanded to 128Gbaud baud rate and 12THz bandwidth in the C+L band. With the advent of the era of single-wave 800G and above, high baud rates are combined with high-order modulation, dense wavelength division multiplexing / ultra-dense wavelength division multiplexing technology, and the channel spacing is getting smaller and smaller, and the number of channels is increasing, which will cover the S+C+L band.

[0003] In addition to optical communication scenarios, the application of LiDAR is also a hot topic. The frequency modulated continuous wave optical phased array (FMCW-OPA) LiDAR technology is one of the most promising directions. This technology not only requires the narrow line width of the laser to increase the detection distance, but also requires the high speed and wide tuning range of the laser to improve the scanning range of the LiDAR.

[0004] The more mature solutions for achieving wide-range narrow linewidth lasers include DFB lasers and DBR lasers. Since DFB lasers and DBR lasers use grating filters to compress the linewidth, and inject different concentrations of carriers to cause the refractive index of the grating structure to change, thereby achieving wavelength tuning, the linewidth compression and wavelength tuning capabilities of a single tube are greatly limited. Usually, the linewidth compression of a single tube of a DFB laser is in the order of 100kHz, and the tuning range is only 2-3nm. To achieve a tuning range of more than 100nm, the design and process of the DFB laser array are extremely difficult; the linewidth compression of a single tube of a DBR laser is in the order of MHz, and the tuning range is 5-10nm. Although the tuning range is larger than that of a DFB laser, the linewidth compression capability is limited.

[0005] Another solution to achieve ultra-wide wavelength tuning is an external cavity tunable external cavity semiconductor laser, which achieves wavelength tuning and line width narrowing through an external cavity. Specific solutions include solutions based on diffraction gratings, fiber gratings, and microring resonators as external cavities. Although the grating external cavity type tunable narrow line width laser has excellent line width performance and a wide tuning range, it is large in size, complex in packaging, difficult in optical path alignment, and has serious mechanical tuning lag, which will reduce the reliability of the laser. The microring resonator type tunable narrow line width laser increases the tuning range of the laser through the vernier effect; at the same time, it uses the thermo-optical effect, carrier injection effect, or electro-optical effect to achieve wavelength switching. The microring resonator type tunable narrow line width laser is far superior to the tunable narrow line width laser based on grating elements in terms of reliability, low power consumption, wavelength tunability, and line width characteristics.

[0006] Tunable narrow-linewidth lasers based on microring resonators use different waveguide materials such as SiON, Si, Si3N4, and LiNbO3 (lithium niobate). Research on silicon-based narrow-linewidth tunable lasers based on these material systems has made certain progress, but they all have their own shortcomings: SiON external cavity waveguide has low refractive index contrast, large size, small thermo-optical coefficient, and high power consumption. For example, the external cavity laser based on SiON waveguide developed by NEC Corporation is nearly 10 times larger than that based on Si waveguide, with a tuning range of 60nm; Si external cavity waveguide has two-photon absorption effect, which leads to increased waveguide loss and limited output power, seriously affecting the linewidth compression of the laser. Although the University of California has reduced Si waveguide loss through special process optimization and achieved linewidth compression below 100Hz and a tuning range of 118nm, the limitations of nonlinear effects have not been fundamentally solved. According to reports of other external cavity lasers based on Si waveguide, the linewidth is still above tens of kHz and the tuning range is less than about 60nm; the preparation process of lithium niobate external cavity waveguide is immature, the waveguide loss is large, and it is incompatible with the silicon photonic platform process. In addition, the refractive index difference between lithium niobate and III-V materials is large, making it difficult to achieve high-efficiency coupling integration. In addition, the electro-optic tuning efficiency of the ridge waveguide on the X-cut LNOI platform can be effectively improved by shallow etching. The shallowly etched lithium niobate ridge waveguide does not have strong light confinement characteristics, and a curved waveguide with a sufficiently large radius must be selected to ensure low-loss transmission of the microring. On the other hand, efficient electro-optic tuning requires a sufficiently long modulation arm to meet the requirements. The above limitations lead to a large circumference of the lithium niobate microring, which makes its free spectral range (FSR) very small, making it difficult to achieve ultra-wide wavelength tuning; Si3N4 external cavity waveguide has certain advantages in line width compression and tuning range, but Si3N4 has a small thermo-optic coefficient, and the power consumption is large when tuning using the thermo-optic effect, and the wavelength switching rate is slow, only in the microsecond level. In addition, when tuning over a large range, the main problem is that the gain spectral range and output power spectrum of the gain chip cannot match it, making it difficult to achieve large-scale high-power output. Summary of the invention

[0007] In view of this, the present invention aims to provide a semiconductor laser which utilizes different waveguide materials for monolithic integration to achieve high power, narrow linewidth, and wide range tuning.

[0008] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0009] A high-power narrow-linewidth wide-range tunable laser integrated with a multi-material system comprises a silicon substrate and a silicon dioxide buried oxide layer arranged on the silicon substrate, and also comprises a III-V group gain chip, a mode converter, a tunable Sagnac ring composed of a silicon waveguide and bonded to the III-V group gain chip, and a series three-microring resonator composed of a lithium niobate / silicon nitride composite and bonded to the mode converter. The series three-microring resonator and the tunable Sagnac ring form an equivalent resonant cavity.

[0010] Furthermore, the three-microring resonator in series adopts a silicon nitride waveguide as a whole, and a first silicon dioxide cladding is deposited around the silicon nitride waveguide. The silicon nitride waveguide includes a phase modulation arm connected to the mode converter, a first curved waveguide connected to the phase modulation arm, an input end waveguide connected to the first curved waveguide, a first racetrack-type microring resonator coupled to the input end waveguide, a first cascade waveguide coupled to the first racetrack-type resonator, a second racetrack-type microring resonator coupled to the first cascade waveguide, a second cascade waveguide coupled to the second racetrack-type microring resonator, a third racetrack-type microring resonator coupled to the second cascade waveguide, a third cascade waveguide coupled to the third racetrack-type microring resonator, and a third cascade waveguide coupled to the third cascade waveguide. A second curved waveguide connected to the waveguide and an output end waveguide connected to the second curved waveguide are bonded with a lithium niobate film above the first racetrack resonator, the second racetrack resonator and the third racetrack resonator, a first gold electrode for high-speed wavelength switching is deposited on the lithium niobate film on both sides of the second racetrack microring resonator, a second silicon dioxide cladding is deposited on the lithium niobate film in an area avoiding the first gold electrode, nickel-chromium heating electrodes for wavelength tuning are deposited on the second silicon dioxide cladding at positions corresponding to the first racetrack microring resonator, the second racetrack microring resonator and the third racetrack microring resonator, and a nickel-chromium heating electrode for phase modulation is deposited on the second curved waveguide.

[0011] Furthermore, a third silicon dioxide cladding having the same thickness as the lithium niobate film is deposited on the silicon nitride waveguide, the tunable Sagnac ring adopts a silicon waveguide as a whole and is deposited on the third silicon dioxide cladding, a second silicon dioxide cladding is deposited around the silicon waveguide, the silicon waveguide includes a first straight waveguide connected to the mode converter, a first directional coupler connected to the first straight waveguide, a second straight waveguide connected to the first directional coupler, a second directional coupler connected to the second straight waveguide, a ring waveguide connected to the second directional coupler, a third straight waveguide symmetrical to the second straight waveguide and having one end connected to the second directional coupler and the other end connected to the first directional coupler, and a feedback end waveguide connected to the first directional coupler, a nickel-chromium heating electrode for phase modulation is deposited on the second straight waveguide, a III-V group gain chip is bonded to the first straight waveguide, and a third gold electrode is deposited on the III-V group gain chip.

[0012] Furthermore, the electrodes of the phase modulation arm are second gold electrodes deposited on the lithium niobate film and located on both sides of the first curved waveguide for electro-optical modulation.

[0013] Furthermore, the mode converter is composed of a silicon mode spot converter and a silicon nitride mode spot converter. The silicon mode spot converter is a cone head formed at the end of the first straight waveguide away from the first directional coupler, and the silicon nitride mode spot converter is a cone head formed at the end of the first curved waveguide away from the input waveguide. The silicon mode spot converter and the silicon nitride mode spot converter are staggered at different heights.

[0014] Furthermore, the circumferences of the first racetrack-type microring resonator, the second racetrack-type microring resonator and the third racetrack-type microring resonator are all different. The circumferences of the first racetrack-type microring resonator and the second racetrack-type microring resonator are not much different. In order to improve the side mode suppression ratio, the circumference of the third racetrack-type microring resonator is more different than the circumferences of the first and second racetrack-type microring resonators.

[0015] Compared with the prior art, the invention can achieve the following beneficial effects:

[0016] 1. The three-microring resonator in series of lithium niobate / silicon nitride composite waveguide and the tunable Sagnac ring of silicon waveguide constitute an equivalent resonant cavity structure, which is used to break through the wavelength tuning limit in the free spectrum range and realize the fine control of the S+C+L large-range single longitudinal mode. Among them, one end of the narrow linewidth large-range tunable laser adopts a three-microring resonator in series. By designing and optimizing the resonant cavity structure based on the three-microring series connection, a large-range free spectrum region with high longitudinal mode gain difference is realized, and the reflectivity is adjustable through a directional coupler. The other end of the narrow linewidth large-range tunable laser adopts a tunable Sagnac ring, and the thermo-optical effect is used to realize the resonant switching of the two free spectrum ranges, so that the tuning range is not limited by the free spectrum range.

[0017] 2. The three-microring resonator in series uses lithium niobate / silicon nitride composite waveguides to optimize the mutual coupling and functional regulation mechanism of multiple physical fields and realize the multifunctional on-chip integration of multiple material systems. Fully integrate the electro-optical effect of lithium niobate film, the low loss of silicon nitride waveguide, the low power consumption of silicon waveguide and the high gain advantages of III-V gain chips, optimize the multi-physical synergy mechanism, and heterogeneously integrate the III-V gain chip with the passive external cavity silicon waveguide chip to reduce the volume and power consumption. Design a heterogeneous integrated transition layer to achieve efficient coupling between the active waveguide of the III-V gain chip and the silicon nitride waveguide. Using ultra-thin bonding technology, the silicon nitride waveguide and lithium niobate film are heterogeneously integrated to achieve linewidth compression and rapid wavelength switching.

[0018] 3. Use the quantum structure enhancement effect to precisely control the properties of epitaxial materials, solve the problem of limited gain spectrum range of III-V gain chips, and achieve a wide range, flat, high-gain output spectrum. On the one hand, a wide-spectrum chirped quantum well structure is proposed to eliminate the fixed energy band boundary restrictions on photon frequency and achieve a wider range of photon frequency absorption and emission. On the other hand, explore the epitaxial growth technology of high-density quantum dots to achieve selective absorption and emission of multiple energies by forming discrete energy levels. On this basis, expand the gain spectrum of III-V gain chips, and compress the line width of the laser by reducing free carrier interactions.

[0019] 4. Adopting electrically pumped phase-matched array lossy waveguides to overcome the power limitation of single-mode size effect and realize high-power laser output of narrow linewidth tunable lasers. By increasing the width of single-mode active waveguides to generate multiple high-order modes, and constructing a lateral coupling loss structure with an effective refractive index strictly matching the high-order modes in the active laser waveguide, the fundamental mode of the laser is ensured not to be lost, while the high-order modes are lost, thereby increasing the mode gain difference between the fundamental mode and the high-order modes. This innovative design still maintains the single transverse mode output of the active waveguide under high current injection and increases the output power several times. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0021] Figure 1 It is a schematic diagram of the structure of a high-power narrow-linewidth wide-range tunable laser integrated with a multi-material system according to an embodiment of the invention;

[0022] Figure 2 It is a schematic diagram of a top view of the structure of a high-power narrow-linewidth wide-range tunable laser integrated with a multi-material system according to an embodiment of the invention;

[0023] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional structure along line a-a';

[0024] Figure 4 yes Figure 2 Schematic diagram of the cross-sectional structure along line b-b'.

[0025] Description of the accompanying drawings: tunable Sagnac ring a, III-V group gain chip b, mode converter c, three-microring resonator in series d, silicon substrate 1, silicon dioxide buried oxide layer 2, first silicon dioxide cladding 3, lithium niobate film 4, third silicon dioxide cladding 5, phase modulation arm 7, first curved waveguide 8, input end waveguide 9, first racetrack type microring resonator 10, first cascade waveguide 11, second racetrack type microring resonator 12, second cascade waveguide 13, third racetrack type microring resonator 14, third cascade waveguide 15, second curved Curved waveguide 16, output end waveguide 17, first nickel-chromium heating electrode 18, second nickel-chromium heating electrode 19, third nickel-chromium heating electrode 20, first gold electrode 21, first straight waveguide 22, third gold electrode 24, first directional coupler 25, second straight waveguide 26, second directional coupler 27, ring waveguide 28, third straight waveguide 29, feedback end waveguide 30, fourth nickel-chromium heating electrode 31, second silicon dioxide cladding 32, fifth nickel-chromium heating electrode 33, silicon nitride waveguide 34, silicon waveguide 35, second gold electrode 36. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0027] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0028] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0029] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0030] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0031] The invention provides a high-power narrow-linewidth wide-range tunable laser integrated with a multi-material system, which utilizes the excellent properties of different waveguide materials. The equivalent resonant cavity of the laser consists of two parts. The first part is a three-microring resonator in series. The three-microring resonator in series uses a lithium niobate / silicon nitride composite waveguide, and uses the electro-optical effect of the lithium niobate film and the low loss of silicon nitride to achieve fast tuning and linewidth compression. The second part is a tunable Sagnac ring, which uses a silicon waveguide and is bonded on-chip with a III-V group gain chip to achieve low-power wide-spectrum tuning of the laser rear cavity surface reflectivity.

[0032] like Figure 1-Figure 4 As shown, the present invention provides a high-power narrow-linewidth wide-range tunable laser integrated with a multi-material system, including a silicon substrate 1, a silicon dioxide buried oxide layer 2 arranged on the silicon substrate 1, and a tunable Sagnac ring a, a III-V group gain chip b, a mode converter c, and a series three-microring resonator d respectively arranged on the silicon dioxide buried oxide layer 2, wherein the tunable Sagnac ring a is composed of a silicon waveguide and bonded to the III-V group gain chip b, the series three-microring resonator d is composed of a lithium niobate / silicon nitride composite and bonded to the mode converter c, and the series three-microring resonator d and the tunable Sagnac ring a form an equivalent resonant cavity.

[0033] The function of the tunable Sagnac ring a is to realize the resonant switching between two free spectral ranges by utilizing the thermo-optical effect, so that the tuning range is not limited by the range of the free spectral region.

[0034] The III-V group gain chip b is a semiconductor optical amplifier, which is used to provide spectral gain. The gain spectrum range determines the maximum wavelength tuning range of the laser.

[0035] The function of the mode converter c is to realize the mode conversion between the silicon waveguide and the silicon nitride waveguide and reduce energy loss.

[0036] The function of the three-microring resonator d in series is to change the electric field on both sides of the microring waveguide by applying different DC voltages to the electrodes, thereby changing the refractive index of the waveguide and the resonant wavelength of the filter structure to achieve the purpose of tuning the wavelength.

[0037] The three-microring resonator d in series adopts a silicon nitride waveguide 34 as a whole, and a first silicon dioxide cladding 3 is deposited around the silicon nitride waveguide. The silicon nitride waveguide 34 includes a phase modulation arm 7 connected to the mode converter c, a first curved waveguide 8 connected to the phase modulation arm 7, an input end waveguide 9 connected to the first curved waveguide 8, a first racetrack-type microring resonator 10 coupled to the input end waveguide 9, a first cascade waveguide 11 coupled to the first racetrack-type resonator 10, and a first cascade waveguide 11 coupled to the first cascade waveguide 11. A second racetrack microring resonator 12 coupled to the second racetrack microring resonator 12, a second cascade waveguide 13 coupled to the second racetrack microring resonator 12, a third racetrack microring resonator 14 coupled to the second cascade waveguide 13, a third cascade waveguide 15 coupled to the third racetrack microring resonator 14, a second curved waveguide 16 connected to the third cascade waveguide 15, and an output end waveguide 17 connected to the second curved waveguide 16, in the first racetrack microring resonator 10, the second racetrack microring resonator 12, the third cascade waveguide 15 coupled to the third racetrack microring resonator 14, A lithium niobate film 4 is deposited above the three-racetrack microring resonator 14, and a first gold electrode 21 for high-speed wavelength switching and a second gold electrode 36 for electro-optical modulation are deposited on the lithium niobate film 4 on both sides of the second racetrack microring resonator 12, and a second silicon dioxide cladding 32 is deposited on the lithium niobate film 4 in an area avoiding the first gold electrode 21 and the second gold electrode 36, and a first nickel-chromium heating electrode 18 for wavelength tuning is deposited on the second silicon dioxide cladding 32 at a position corresponding to the first racetrack microring resonator 10, a second nickel-chromium heating electrode 19 for wavelength tuning is deposited on the second silicon dioxide cladding 32 at a position corresponding to the second racetrack microring resonator 12, a third nickel-chromium heating electrode 20 for wavelength tuning is deposited on the second silicon dioxide cladding 32 at a position corresponding to the third racetrack microring resonator 14, and a fourth nickel-chromium heating electrode 31 for phase modulation is deposited on the second curved waveguide 16.

[0038] The electrodes of the phase modulation arm 7 are second gold electrodes 36 deposited on the lithium niobate film 4 and located on both sides of the first curved waveguide 8, and are used for electro-optical modulation.

[0039] The circumference of the second racetrack microring resonator 12 is slightly different from that of the first racetrack microring resonator 10 , and the circumference of the third racetrack microring resonator 14 is different from that of the first racetrack microring resonator 10 and the second racetrack microring resonator 12 .

[0040] The three-microring resonator d in series based on lithium niobate / silicon nitride composite waveguide utilizes the electro-optic effect of lithium niobate film, whose electro-optic coefficient is about 31pm / V. Electrodes are made on the lithium niobate film, and a modulation signal is applied to the phase zone or microring. The external electric field will cause the crystal refractive index to change, causing the transmission spectrum near the resonant wavelength to change, thereby changing the resonant frequency and achieving the purpose of high-speed wavelength switching.

[0041] A third silicon dioxide cladding layer 5 having the same thickness as the lithium niobate film 4 is deposited on the output waveguide 17 .

[0042] The tunable Sagnac ring a is entirely made of a silicon waveguide 35 and is deposited on the third silicon dioxide cladding 5. A second silicon dioxide cladding 32 is deposited around the silicon waveguide 35. The second silicon dioxide cladding 32 is entirely covered on the third silicon dioxide cladding 5 and the lithium niobate film 4.

[0043] The silicon waveguide 35 includes a first straight waveguide 22 connected to the mode converter c, a first directional coupler 25 connected to the first straight waveguide 22, a second straight waveguide 26 connected to the first directional coupler 25, a second directional coupler 27 connected to the second straight waveguide 26, a ring waveguide 28 connected to the second directional coupler 27, a third straight waveguide 29 symmetrical to the second straight waveguide 26 and connected to the second directional coupler 27 at one end and connected to the first directional coupler 25 at the other end, and a feedback end waveguide 30 connected to the first directional coupler 25, a fifth nickel-chromium heating electrode 33 for phase modulation is deposited on the second straight waveguide 26, a III-V group gain chip b is bonded to the first straight waveguide 22, and a third gold electrode 24 is deposited on the III-V group gain chip b.

[0044] The first gold electrode 21 and the second gold electrode 36 are directly deposited on the lithium niobate film 4, and there is a layer of silicon dioxide between the first nickel-chromium heating electrode 18, the second nickel-chromium heating electrode 19, the third nickel-chromium heating electrode 20, the fourth nickel-chromium heating electrode 31, the fifth nickel-chromium heating electrode 33 and the lithium niobate film 4.

[0045] The mode converter c is composed of a silicon mode spot converter and a silicon nitride mode spot converter, which completes the mode conversion of light in different waveguide structures and minimizes the energy loss of light in different waveguides. The silicon mode spot converter is a cone head formed at the end of the first straight waveguide 22 away from the first directional coupler 25, and the silicon nitride mode spot converter is a cone head formed at the end of the first curved waveguide 8 away from the input end waveguide 9. The silicon mode spot converter and the silicon nitride mode spot converter are staggered at different heights, with a second silicon dioxide cladding 32 in between.

[0046] The present invention adopts a tuning method that compensates for the thermo-optic effect and the linear electro-optic effect to achieve the goal of wide tuning and fast tuning. Heating electrodes are made on the three-microring resonator in series, the directional coupler and the tunable Sagnac ring for thermal tuning. By applying different DC voltages to the electrodes, the electric field on both sides of the microring waveguide is changed, thereby changing the refractive index of the waveguide and the resonant wavelength of the filter structure, thereby achieving the purpose of tuning the wavelength. The electrodes in the phase modulation arm area change the resonant spectrum of the Fabry-Perot cavity formed by the laser as a whole by changing the refractive index of the phase modulation arm structure, thereby fine-tuning the longitudinal mode and improving the side mode suppression ratio of the laser.

[0047] The high-power narrow-linewidth wide-range tunable laser integrated with a multi-material system prepared by the present invention has a wavelength tuning range greater than 165nm, can cover the S+C+L bands, has a spectral linewidth less than 1kHz, a maximum output power greater than 100mW, a side mode suppression ratio greater than 50dB, and a wavelength switching time in the ns level, which can meet the urgent needs of the next generation of ultra-high-speed coherent optical communications for multi-band large-capacity transmission and frequency-modulated continuous-wave optical phased array lidar for narrow-linewidth tunable lasers.

[0048] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0049] The above specific implementations do not constitute a limitation on the protection scope of the present invention. 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 modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-power narrow-linewidth wide-range tunable laser integrated with a multi-material system, comprising a silicon substrate and a silicon dioxide buried oxide layer disposed on the silicon substrate, characterized in that: The invention also includes a III-V group gain chip, a mode converter, a tunable Sagnac ring composed of a silicon waveguide and bonded to the III-V group gain chip, and a series three-microring resonator composed of a lithium niobate / silicon nitride composite and bonded to the mode converter, wherein the series three-microring resonator and the tunable Sagnac ring form an equivalent resonant cavity; the series three-microring resonator adopts a silicon nitride waveguide as a whole, and a first silicon dioxide cladding is deposited around the silicon nitride waveguide; the silicon nitride waveguide includes a phase modulation arm connected to the mode converter, a first curved waveguide connected to the phase modulation arm, an input end waveguide connected to the first curved waveguide, a first racetrack-type microring resonator coupled to the input end waveguide, a first cascade waveguide coupled to the first racetrack-type resonator, a second racetrack-type microring resonator coupled to the first cascade waveguide, and a second racetrack-type microring resonator coupled to the second racetrack-type microring resonator. A coupled second cascade waveguide, a third racetrack-type microring resonator coupled to the second cascade waveguide, a third cascade waveguide coupled to the third racetrack-type microring resonator, a second curved waveguide connected to the third cascade waveguide, and an output-end waveguide connected to the second curved waveguide; a lithium niobate film is bonded above the first racetrack-type resonator, the second racetrack-type resonator, and the third racetrack-type resonator; first gold electrodes for switching wavelengths are deposited on the lithium niobate film on both sides of the second racetrack-type microring resonator; a second silicon dioxide cladding is deposited on the lithium niobate film in an area avoiding the first gold electrode; nickel-chromium heating electrodes for tuning wavelengths are deposited on the second silicon dioxide cladding at positions corresponding to the first racetrack-type microring resonator, the second racetrack-type microring resonator, and the third racetrack-type microring resonator, and a nickel-chromium heating electrode for phase modulation is deposited on the second curved waveguide.

2. The multi-material system integrated high-power narrow-linewidth wide-range tunable laser according to claim 1, characterized in that: A third silicon dioxide cladding with the same thickness as the lithium niobate film is deposited on the silicon nitride waveguide, the tunable Sagnac ring adopts a silicon waveguide as a whole and is deposited on the third silicon dioxide cladding, a second silicon dioxide cladding is deposited around the silicon waveguide, the silicon waveguide comprises a first straight waveguide connected to a mode converter, a first directional coupler connected to the first straight waveguide, a second straight waveguide connected to the first directional coupler, a second directional coupler connected to the second straight waveguide, a ring waveguide connected to the second directional coupler, a third straight waveguide symmetrical to the second straight waveguide and having one end connected to the second directional coupler and the other end connected to the first directional coupler, and a feedback end waveguide connected to the first directional coupler, a nickel-chromium heating electrode for phase modulation is deposited on the second straight waveguide, a III-V group gain chip is bonded to the first straight waveguide, and a third gold electrode is deposited on the III-V group gain chip.

3. The multi-material system integrated high-power narrow-linewidth wide-range tunable laser according to claim 2, characterized in that: The mode converter consists of a silicon mode spot converter and a silicon nitride mode spot converter. The silicon mode spot converter is a cone head formed at the end of the first straight waveguide away from the first directional coupler, and the silicon nitride mode spot converter is a cone head formed at the end of the first curved waveguide away from the input waveguide. The silicon mode spot converter and the silicon nitride mode spot converter are staggered at different heights.

4. The multi-material system integrated high-power narrow-linewidth wide-range tunable laser according to claim 1, characterized in that: The electrodes of the phase modulation arm are second gold electrodes deposited on the lithium niobate film and located on both sides of the first curved waveguide for electro-optical modulation.

5. The multi-material system integrated high-power narrow-linewidth wide-range tunable laser according to claim 1, characterized in that: The circumferences of the first racetrack-type microring resonator, the second racetrack-type microring resonator and the third racetrack-type microring resonator are all different.

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