On-chip light source based on quantum dot laser mutual injection system

Abstract

The invention provides an on-chip light source based on a quantum dot laser mutual injection system, which comprises a chip substrate, a master quantum dot laser and a slave quantum dot laser, and is characterized in that a waveguide is arranged between the master quantum dot laser and the slave quantum dot laser; the main quantum dot laser and the slave quantum dot laser are completely identical in structure and are respectively provided with a buffer layer and an active layer, the buffer layer of the main quantum dot laser and the buffer layer of the slave quantum dot laser are fixedly arranged on the chip substrate, and the waveguide is arranged between the active layer of the main quantum dot laser and the active layer of the slave quantum dot laser. The beneficial effects of the invention are that the relative intensity noise (RIN) and spectral line width of output laser can be significantly reduced, and the output laser power is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor optoelectronic technology, and in particular to an on-chip light source based on a quantum dot laser mutual injection system. Background Art

[0002] On-chip integration is one of the key trends in the development of modern optoelectronics and communication technologies. With the rapid expansion of data centers, optical interconnects, and optical communication systems, the demand for higher bandwidth, lower power consumption, and more compact systems is growing. In traditional optical communication systems, discrete optoelectronic devices need to be connected to each other through optical fibers and connectors, which not only leads to large system size, high power consumption, and expensive manufacturing costs, but also brings signal delay and stability issues. Therefore, realizing on-chip integration and integrating multiple optoelectronic devices into a single chip can not only significantly reduce system complexity and cost, but also increase data transmission speed, reduce power consumption, and improve system reliability.

[0003] The importance of on-chip integration is mainly reflected in the following aspects: First, it greatly reduces the insertion loss and noise caused by the transmission of optical signals between devices, thereby improving the signal quality and stability of the system. Secondly, on-chip integration helps to increase the density of optical communication systems, making higher bandwidth and more efficient data transmission possible. In addition, on-chip integration can reduce the physical distance between components, thereby reducing latency and power consumption, making it particularly critical in applications such as high-performance computing, data centers, and 5G networks that require extremely high speed and efficiency. Therefore, on-chip integration represents an important technical direction in the field of optoelectronics, laying the foundation for the realization of future high-speed, low-power optical communications and information processing systems, while promoting the application of smaller and more efficient photonic integrated circuits.

[0004] In the process of promoting the development of on-chip integration technology, the performance of the light source has become a core factor affecting the efficiency of the entire system. In integrated photonic circuits, the light source is not only the starting point of data transmission, but also directly determines the signal quality and reliability of the system. For on-chip photonic integrated circuits (PICs), the ideal light source needs to have the characteristics of low power consumption, high bandwidth, narrow spectral linewidth and low relative intensity noise (RIN) to ensure that the system maintains excellent signal integrity under high data rate and long-distance transmission conditions. In addition, light sources with high output power and high modulation efficiency are also crucial to meet the needs of higher bandwidth in the future. However, there are problems such as mismatch dislocations, microcracks and anti-phase domain defects between traditional light-emitting III-V materials and silicon materials. The laser will produce a high dislocation density during the manufacturing process, which inevitably reduces the luminous efficiency and output light quality of the device, increases the RIN and spectral linewidth of the output light, and shortens the device life. Therefore, how to achieve a stable, low-noise, high-quality light source in an on-chip integration environment has become a key bottleneck in the development of on-chip integration technology.

[0005] Compared with the traditional quantum well structure, the discrete distribution characteristics of the quantum dot (QD) structure make it more tolerant to epitaxial growth defects on silicon. It can effectively deflect or clamp defects to prevent loop formation, and position carriers to prevent lateral diffusion or non-radiative recombination, thereby greatly reducing the impact of dislocation defects on the optical properties of the laser. Therefore, silicon-based quantum dot lasers can be used as the best choice for on-chip light sources. In order to further output the RIN and spectral linewidth of the light to meet the requirements of the on-chip light source, external control methods such as optical feedback and unidirectional light injection locking can be used. By adjusting the external cavity configuration, including the two key parameters of the external cavity round-trip time and the intensity of optical feedback, the re-injected light will cause disturbances in the photon density in the active region of the laser, resulting in fluctuations in the carrier density and optical gain, which in turn causes significant changes in the output light of the silicon-based quantum dot laser. Optical feedback can significantly reduce the spectral linewidth and RIN of quantum dot lasers, but in the feedback space composed of the external cavity round-trip time (external cavity length) and the optical feedback intensity, only a small area can reduce the RIN and spectral linewidth of the laser and improve the output light quality, which is very likely to cause the laser to exhibit complex dynamic behavior. Therefore, although optical feedback is expected to be used to reduce the spectral linewidth and RIN of silicon-based quantum dot lasers, the adjustment process requires precise control and precise regulation of various parameters to achieve the desired effect. One-way optical injection locking is a technology that injects light from an external tunable laser into a quantum dot laser to achieve forced synchronization. By increasing the photon lifetime in the laser, the output light is stabilized, significantly reducing the RIN and spectral linewidth. Compared with the optical feedback method, external one-way optical injection locking is easier to adjust, but it is very demanding on the tunable laser as the master laser. Only when the output light of the tunable laser has high quality and narrow linewidth characteristics can the quantum dot laser as a slave laser exhibit excellent output light quality. In addition, the typical unidirectional optical injection locking system relies on discrete lasers and requires the use of optical isolators or circulators to prevent the light from the slave laser from being injected back into the master laser and causing interference to the master laser. However, the use of these devices increases the complexity and cost of the system and hinders the realization of monolithic integration, which is not conducive to the scalability and practical application of monolithic integration. Summary of the invention

[0006] In order to solve the problems in the prior art, the present invention provides an on-chip light source based on a quantum dot laser mutual injection system. By arranging a chip substrate, a master quantum dot laser and a slave quantum dot laser that cooperate with each other in the on-chip light source based on the quantum dot laser mutual injection system, the output laser of the master quantum dot laser and the output laser of the slave quantum dot laser can be mutually coupled through a waveguide to achieve mutual injection locking. By integrating two quantum dot (QD) lasers on the same chip for mutual injection locking, a quantum dot laser mutual injection system is constructed. The system significantly reduces the relative intensity noise (RIN) and spectral linewidth of the output light, and greatly improves the output light power, so that the output light of the silicon-based quantum dot laser is sufficiently stable and has sufficient energy to meet the needs of on-chip integration. Compared with traditional optical feedback and unidirectional optical injection locking methods, precise control is not required, the operation is simple, and no additional components such as optical isolators are required, thereby simplifying the system architecture, significantly improving the reliability and stability of the system, and solving the problems of complex system, high cost and unfavorable on-chip integration of the laser using optical feedback and unidirectional optical injection locking methods in the prior art.

[0007] The present invention provides an on-chip light source based on a quantum dot laser mutual injection system, comprising a chip substrate, a master quantum dot laser and a slave quantum dot laser, wherein the master quantum dot laser and the slave quantum dot laser are fixedly integrated on the chip substrate, a waveguide is provided between the master quantum dot laser and the slave quantum dot laser, and the output laser of the master quantum dot laser and the output laser of the slave quantum dot laser can be mutually coupled through the waveguide to achieve mutual injection locking.

[0008] The present invention is further improved, the structures of the master quantum dot laser and the slave quantum dot laser are exactly the same and both are provided with a buffer layer and an active layer, the buffer layer of the master quantum dot laser and the buffer layer of the slave quantum dot laser are fixedly arranged on the chip substrate, and the waveguide is arranged between the active layer of the master quantum dot laser and the active layer of the slave quantum dot laser.

[0009] The present invention is further improved, and the structures of the master quantum dot laser and the slave quantum dot laser are both quantum dot micro-disk lasers or vertical cavity surface emission quantum dot lasers or quantum dot distributed feedback lasers or distributed Bragg reflection lasers.

[0010] The present invention is further improved in that the manufacturing material of the quantum dot laser is InAs / GaAs quantum dot material or InAs / InP quantum dot material.

[0011] The present invention is further improved in that the chip substrate is a silicon-based substrate.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides an on-chip light source based on a quantum dot laser mutual injection system, by arranging a chip substrate, a master quantum dot laser and a slave quantum dot laser that cooperate with each other in the on-chip light source based on the quantum dot laser mutual injection system, the output laser of the master quantum dot laser and the output laser of the slave quantum dot laser can be mutually coupled through a waveguide to achieve mutual injection locking, and a quantum dot laser mutual injection system is constructed, which greatly improves the output performance of the light source, so that the output laser of the silicon-based quantum dot laser is sufficiently stable and has sufficient energy to meet the needs of on-chip integration; the mutual injection system effectively suppresses the phase fluctuation and photon number fluctuation of the laser output, reduces the relative intensity noise (RIN), and narrows the spectral linewidth from 1.2MHz during free operation to 0.008MHz, which is suitable for high coherence and narrow linewidth Applications, such as coherent communications and optical sensing; the mutual injection system can achieve an output power 2.2 times that of a free-running laser at a lower coupling ratio, significantly improving the efficiency of the light source, making it more suitable for low-power, high-performance application requirements of on-chip integrated photonic circuits; by optimizing the mutual injection locking technology, the system's spectral noise (FN) and low-frequency RIN in different spectral ranges are significantly reduced, enhancing the frequency domain stability of the laser output, thereby improving the accuracy and reliability of signal transmission; the quantum dot laser mutual injection system is used as an on-chip light source. Compared with the traditional optical feedback and unidirectional optical injection locking methods, the quantum dot laser mutual injection system does not require precise control, is easy to operate, and does not require additional components such as optical isolators, thereby simplifying the system architecture, significantly improving the reliability and stability of the system, and solving the problems of the existing technology that the laser uses optical feedback and unidirectional optical injection locking methods, which are complex, costly, and not conducive to on-chip integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the solutions in the present application or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 This is a schematic diagram of an on-chip light source based on a mutual injection system of a master quantum dot laser and a slave quantum dot laser according to the present invention;

[0015] Figure 2 It is a schematic block diagram of the application of an on-chip light source based on a quantum dot laser mutual injection system of the present invention;

[0016] Figure 3 A schematic diagram of the relationship between the electronic structure and carrier dynamics of the master quantum dot laser and the slave quantum dot laser in the active region of the present invention;

[0017] Figure 4 is the normalized power of the mutual injection quantum dot laser of the present invention;

[0018] Figure 5 The FN spectra and spectral line widths under different coupling ratios of the present invention;

[0019] Figure 6 : RIN spectra and low-frequency RIN values ​​under different coupling ratios of the present invention. DETAILED DESCRIPTION

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field of this application; the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit the application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0021] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0022] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0023] like Figure 1-Figure 6 As shown, the present invention provides an on-chip light source based on a quantum dot laser mutual injection system, comprising a chip substrate, a master quantum dot laser and a slave quantum dot laser, wherein the master quantum dot laser and the slave quantum dot laser are fixedly integrated on the chip substrate, a waveguide is provided between the master quantum dot laser and the slave quantum dot laser, the output laser of the master quantum dot laser and the output laser of the slave quantum dot laser can be mutually coupled through the waveguide to achieve mutual injection locking, the structures of the master quantum dot laser and the slave quantum dot laser are completely the same and both are provided with a buffer layer and an active layer, the buffer layer of the master quantum dot laser and the buffer layer of the slave quantum dot laser are fixedly provided on the chip substrate, and the waveguide is provided between the active layer of the master quantum dot laser and the active layer of the slave quantum dot laser. In this embodiment, Figure 2This is an application example of the on-chip light source based on the quantum dot laser mutual injection system of the present invention. Multiple laser light sources are integrated in the applied photonic system, including an atom capture laser light source, an atom detection laser light source, and a comb pump laser light source. The photons generated by these light sources are transmitted into other functional modules through waveguides. The initial optical signal is processed in the microresonator, and the coherence and stability of the signal are adjusted by frequency selection or injection locking technology to improve the output quality of the system; next, the optical signal processed by the microresonator enters the optical signal modulator, and the optical signal is modulated at high speed to achieve a higher data transmission rate; the modulated optical signal is further transmitted to the optical signal amplifier to increase the signal power and ensure that the signal strength and quality are maintained during long-distance transmission; after completing the optical signal modulation and amplification, the optical signal is coupled from the chip to the external optical fiber through the output grating coupler for further transmission or detection; in the signal detection stage, the detection photodiode module integrated in the system can achieve efficient photoelectric conversion and detection, and ensure the stability of signal processing through a feedback control mechanism. The core of the present invention is to use a quantum dot (QD) laser mutual injection system as an on-chip light source. Compared with traditional light sources, the quantum dot laser mutual injection system significantly reduces the spectral linewidth and relative intensity noise (RIN), while increasing the output optical power, thereby greatly improving the overall performance of the system. This design not only ensures the reliability of the on-chip photonic system in high data rate and high-density communication environments, but also provides strong support for the further development of future quantum communications and on-chip photonic integrated circuits. Therefore, the use of a quantum dot laser mutual injection system as a light source has become a key element in realizing efficient on-chip integrated photonic technology.

[0024] like Figure 1-Figure 6 As shown, the structures of the master quantum dot laser and the slave quantum dot laser are both quantum dot micro-disk lasers or vertical cavity surface emission quantum dot lasers or quantum dot distributed feedback lasers or distributed Bragg reflection lasers; the manufacturing materials of the quantum dot lasers are InAs / GaAs quantum dot materials or InAs / InP quantum dot materials; and the chip substrate is a silicon-based substrate. In this embodiment, Figure 1An integrated solution for an on-chip light source based on a quantum dot laser mutual injection system is demonstrated. Two quantum dot lasers are integrated on the same chip substrate, and their output light is coupled to each other through a waveguide to achieve mutual injection locking. This design can achieve stable light transmission without the need for additional optical isolators or circulators, thereby simplifying the system architecture and reducing power consumption and cost. For ease of explanation, although the common terms "master laser" and "slave laser" in the unidirectional optical injection locking scheme are borrowed, in fact, there is no real hierarchical relationship between the two lasers. The mutual injection system can achieve high-quality light source output on the chip. By reducing the relative intensity noise (RIN) and spectral linewidth, while significantly improving the output optical power, the mutual injection system proposed in the present invention provides sufficient stability and performance for the on-chip integrated light source. This architecture not only meets the compactness and reliability requirements required for on-chip integration, but also lays a solid foundation for high-speed optical communications and on-chip photonic circuit applications.

[0025] In this embodiment, the physical parameters of the two quantum dot lasers in the on-chip mutual injection system are the same, and other parameters of the quantum dot lasers are given here:

[0026]

[0027]

[0028] Table 1 Materials and optical parameters of silicon-based quantum dot lasers

[0029] like Figure 3 As shown, the electronic structure and carrier dynamics relationship of the master quantum dot laser and the slave quantum dot laser in the active region are demonstrated. In this numerical model, it is assumed that the active region contains a five-layer QD structure and there is only one QD ensemble. Therefore, the model only considers the uniform broadening effect, and does not include the inhomogeneous broadening caused by the QD size distribution. In addition, it is assumed that the QD remains electrically neutral, and that electrons and holes exist in pairs as excitons rather than independently. The exciton model of the quantum dot laser includes a two-dimensional carrier reservoir (RS), a quadruple-degenerate excited state (ES), and a doubly-degenerate ground state (GS). When the pump current is injected, the carriers first capture the carriers with a capture time From RS capture to ES, followed by relaxation time Relax from ES to GS. Stimulated emission occurs in GS, resulting in laser output. Due to thermal excitation, carriers may escape from GS to ES and from ES to RS, and the corresponding escape times are and These processes are controlled by the Fermi distribution under quasi-thermal equilibrium conditions. In addition to stimulated emission, carriers also undergo spontaneous emission, and the spontaneous emission time corresponding to each state is and It is worth noting that due to the lattice mismatch between silicon and III-V materials, the non-radiative recombination lifetime τ is also included in the model SRH , is used to describe the SRH recombination process. Therefore, the carrier number N describing the master quantum dot laser and the slave quantum dot laser RS 、N ES 、N GS , photon number S GS And the light field phase φ GS The kinetic rate equation is as follows:

[0030]

[0031]

[0032]

[0033] Where s and m represent the slave quantum dot laser and the master quantum dot laser, respectively. η is the injection efficiency, I is the pump current, q is the electron charge, Γ p is the optical confinement factor, v g is the group velocity, β sp is the spontaneous radiation factor. Coupling coefficient Used to describe the power coupling from one laser cavity to another laser cavity, where R is the reflectivity of the laser end face and L is the cavity length of the quantum dot laser. inj and τ represent the optical power coupling ratio and the coupling delay time between the two quantum dot lasers, respectively, and these two parameters have an important influence on the dynamics of the mutual injection system.

[0034] Initial Phase Depends on the coupling delay time, where ω m and ω s are the lasing frequencies of the master quantum dot laser and the slave quantum dot laser, respectively. The frequency detuning between the two quantum dot lasers is defined as Δω=ω m -ω s To achieve a constant phase difference within the stable locking range, the phase of the main quantum dot laser can be mathematically shifted by At the same time, the phase of the quantum dot laser will be shifted and Respectively represent the material gain of each energy level:

[0035]

[0036] Among them, parameter a RS,ES,GS is the differential gain of the material, D RS is the total number of states in RS, V RSis the volume of the RS region, N B is the number of quantum dots in the active region, V B is the volume of the active region, and ε is the gain compression factor. The occupation probability of carriers at each energy level and Respectively expressed as: Each energy level has an effect on the line width enhancement factor LEF(α H ) are respectively used and It means that its expression is:

[0037]

[0038] Among them, T D is the decoherence time, ω RS,ES,GS are the angular frequencies of the corresponding energy levels. Carrier noise and spontaneous emission noise are characterized by Langevin noise sources. RS 、F ES and F GS represent the carrier noise sources of RS, ES and GS states respectively, and F S and They represent the spontaneous emission noise source and phase noise source of photons respectively. Both carrier noise and spontaneous emission noise are white noises, and these noise sources are δ-correlated:

[0039] <F i (t)F j (t′)>=U ij δ(tt′)

[0040] Among them, indicators i and j represent RS, ES, GS, S and φ coefficient U respectively. ij The expression is:

[0041]

[0042] Other cross-correlation intensities not listed are zero. By performing small signal analysis on the rate square, the linear rate equation in the frequency domain is expressed as follows:

[0043]

[0044] And there are:

[0045]

[0046] In small signal analysis, the gain compression effect is given by a p It can be expressed as δg GS =aδN GS -a p δS GSUsing Cramer's rule, the phase δφ and the photon number δS can be determined GS Therefore, the spectrum noise (FN) and RIN can be expressed as:

[0047]

[0048] Where S GS is the number of photons in the stable operation of quantum dot laser, and ω is the angular frequency. The Schawlow-Townes linewidth Δv of quantum dot laser ST It can be extracted from the high frequency part of the FN spectrum, expressed as Δv ST =2πFN| f＝100GHz ; and the spectral line width Δv OL It can be extracted from the low-frequency part of the FN spectrum, expressed as Δv OL =2πFN| f＝1MHz The spectral linewidth of quantum dot lasers is different from the Schawlow-Townes linewidth due to α H The expression is:

[0049]

[0050] In addition, in order to better compare the improvement effect of mutual injection on the power of quantum dot lasers, normalized power is used for characterization, that is, the ratio of the power value after mutual injection to the power of the free-running quantum dot laser. According to the above theory and formula, the normalized power value of the quantum dot laser in the mutual injection system driven at 1.5 times the pump current is obtained.

[0051] like Figure 4 As shown in the figure, in the mutual injection system, the output power of the quantum dot (QD) laser is significantly improved, and significant gain can be obtained even at a low coupling ratio. Experimental results show that compared with the free-running quantum dot laser, the power output of the mutual injection system can be up to 2.2 times that of the free-running quantum dot laser at the same pump current. This shows that by optimizing the coupling ratio, the mutual injection system can achieve higher output power at lower power consumption, thereby significantly improving the performance of the on-chip light source and meeting the bandwidth requirements of future development.

[0052] like Figure 5As shown in the figure, under different coupling ratio conditions, the FN of the quantum dot laser in the mutual injection system is significantly reduced in the low-frequency region, and compared with the free-running quantum dot laser, the phase fluctuation of the output light is significantly reduced, thereby improving the stability of the laser in the frequency domain. At the same time, the spectral linewidth is also greatly narrowed, from the original 1.2MHz to 0.008MHz, which is very beneficial for applications such as coherent communications that have strict requirements on narrow linewidth. This shows that the mutual injection system has significant advantages in improving the coherence and stability of the laser, and provides strong support for the application of on-chip integrated light sources in high-precision optical communications.

[0053] like Figure 6 As shown in the figure, under different coupling ratio conditions, the RIN of the quantum dot laser in the mutual injection system is significantly reduced over the entire spectrum. Compared with the free-running quantum dot laser, the mutual injection system effectively suppresses the fluctuation of the photon number, thereby improving the accuracy of signal transmission. In addition, under the mutual injection condition, the low-frequency RIN of the quantum dot laser is reduced by nearly 10dB compared to the free-running state. This significant noise suppression effect helps to improve the application performance of on-chip light sources in high-stability optical communications and further ensure the reliable transmission of signals.

[0054] As can be seen from the above, the present invention provides an on-chip light source based on a quantum dot laser mutual injection system. By arranging a chip substrate, a master quantum dot laser and a slave quantum dot laser that cooperate with each other in the on-chip light source based on the quantum dot laser mutual injection system, the output laser of the master quantum dot laser and the output laser of the slave quantum dot laser can be mutually coupled through a waveguide to achieve mutual injection locking, thereby constructing a quantum dot laser mutual injection system, which greatly improves the output performance of the light source, thereby making the output laser of the silicon-based quantum dot laser sufficiently stable and having sufficient energy to meet the needs of on-chip integration; the mutual injection system effectively suppresses the phase fluctuation and photon number fluctuation of the laser output, reduces the relative intensity noise (RIN), and narrows the spectral linewidth from 1.2MHz during free operation to 0.008MHz, which is suitable for applications with high coherence and narrow linewidth, such as coherent communication Signal and optical sensing; the mutual injection system can achieve an output power 2.2 times that of a free-running laser at a lower coupling ratio, significantly improving the efficiency of the light source and making it more suitable for low-power, high-performance applications of on-chip integrated photonic circuits; by optimizing the mutual injection locking technology, the system's spectral noise (FN) and low-frequency RIN in different spectral ranges are significantly reduced, enhancing the frequency domain stability of the laser output, thereby improving the accuracy and reliability of signal transmission; the quantum dot laser mutual injection system is used as an on-chip light source. Compared with the traditional optical feedback and unidirectional optical injection locking methods, it does not require precise control, is easy to operate, and does not require additional components such as optical isolators, thereby simplifying the system architecture and significantly improving the reliability and stability of the system, solving the problems of the existing technology that the laser uses optical feedback and unidirectional optical injection locking methods, which are complex, costly, and not conducive to on-chip integration.

[0055] The specific implementation modes described above are preferred implementation modes of the present invention, and are not intended to limit the specific implementation scope of the present invention. The scope of the present invention includes but is not limited to the specific implementation modes, and all equivalent changes made according to the present invention are within the protection scope of the present invention.

Claims

1. An on-chip light source based on a quantum dot laser mutual injection system, characterized in that: The invention comprises a chip substrate, a master quantum dot laser and a slave quantum dot laser. The master quantum dot laser and the slave quantum dot laser are fixedly integrated on the chip substrate. A waveguide is arranged between the master quantum dot laser and the slave quantum dot laser. The output laser of the master quantum dot laser and the output laser of the slave quantum dot laser can be coupled with each other through the waveguide to realize mutual injection locking.

2. The on-chip light source based on the quantum dot laser mutual injection system according to claim 1, characterized in that: The structures of the master quantum dot laser and the slave quantum dot laser are exactly the same and both are provided with a buffer layer and an active layer. The buffer layer of the master quantum dot laser and the buffer layer of the slave quantum dot laser are fixedly arranged on the chip substrate, and the waveguide is arranged between the active layer of the master quantum dot laser and the active layer of the slave quantum dot laser.

3. The on-chip light source based on the quantum dot laser mutual injection system according to claim 2, characterized in that: The structures of the master quantum dot laser and the slave quantum dot laser are both quantum dot micro-disk lasers or vertical cavity surface emission quantum dot lasers or quantum dot distributed feedback lasers or distributed Bragg reflection lasers.

4. The on-chip light source based on the quantum dot laser mutual injection system according to claim 3, characterized in that: The manufacturing material of the quantum dot laser is InAs / GaAs quantum dot material or InAs / InP quantum dot material.

5. The on-chip light source based on the quantum dot laser mutual injection system according to claim 4, characterized in that: The chip substrate is a silicon-based substrate.

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