On-chip optical amplifier and preparation method thereof

Abstract

The invention relates to the technical field of optical devices, and particularly discloses an on-chip optical amplifier and a preparation method thereof. The oxide layer is covered on the substrate; the waveguide layer is located on the oxide layer, a waveguide main body is arranged in the central area of the waveguide layer, a ridge-shaped or wedge-shaped structure is arranged on the outer side of the waveguide main body in the light path extension direction in a protruding mode, and the width of the ridge-shaped or wedge-shaped structure is gradually increased from the center to the two sides; the gain dielectric layer partially and axially penetrates through an embedded groove formed in the waveguide main body to form a slit structure for concentrating a light field; the gain dielectric layer comprises at least two doping layers, a middle layer and a doping dielectric layer, the doping layers are located on the two sides of the waveguide body respectively and matched with the ridge-shaped or wedge-shaped structure to achieve bilateral amplification of optical signals, the middle layer is contained in a crack structure in the center of the waveguide layer and partially and axially extends into the doping layers on the two sides, and the doping dielectric layer is arranged between the middle layer and the doping dielectric layer. And the doped dielectric layer is filled in the residual space.

Description

Technical Field

[0001] The present application relates to the technical field of optical devices, and in particular to an on-chip optical amplifier and a method for preparing the same. Background Art

[0002] The continuous demand for optical communication capabilities has promoted the development of integrated photonic technology. Chip-level integrated photonic devices and the optical links and optical systems composed of them have greatly reduced the size and power consumption of optical communication devices. Limited by the scale of on-chip photonic devices, erbium doped fiber application amplifiers (EDFA) are generally used to amplify optical signals in situations where a large output optical signal is required. EDFA is a special optical fiber doped with erbium (Er3+) ions in quartz optical fiber. Under the action of pump light, ion beam inversion occurs in the erbium doped optical fiber to produce stimulated radiation, so that the optical signal passing through the fiber core is amplified. However, the traditional EDFA instrument is large in size, which is not conducive to the integration and chipization of related optical devices; and the optical signal transmission between EDFA and chip-level integrated photonic devices often has large optical coupling loss and instability.

[0003] Optical waveguides are on-chip photonic devices that can confine light waves to propagate in them. The preparation of rare earth-doped on-chip optical waveguides by ion implantation and other methods has been reported in related fields (such as the document DOI: 10.1364 / OME.397011) and has been proven to have the ability to amplify optical signals. However, this method of directly doping optical waveguides with ions often introduces defects to the crystal structure of the optical waveguide, resulting in increased light transmission loss, thereby significantly reducing its optical performance.

[0004] The patent document with the publication number "CN115966989A" discloses an on-chip optical amplifier and a method for preparing the same. The on-chip optical amplifier includes an optical waveguide, an optical isolation layer, a substrate, and an ion-doped layer, wherein the ion-doped layer includes a doping layer medium and doping ions, and the optical isolation layer is located between the substrate and the ion-doped layer; the ion-doped layer is tightly coated on the outside of the optical waveguide, or is located between the optical waveguide and the optical isolation layer and is tightly attached to the optical waveguide. Although this method can avoid direct ion implantation into the optical waveguide through the design of the ion-doped layer, thereby reducing the defects of the crystal structure and the optical transmission loss, there are still some challenges and limitations.

[0005] For example, the preparation process of the ion-doped layer is relatively complicated, and the concentration and distribution of the doped ions need to be precisely controlled to ensure the uniformity and reliability of the light amplification effect. At the same time, although the introduction of the optical isolation layer can reduce the direct contact between the ion-doped layer and the optical waveguide, it may also bring additional interface reflection and scattering losses, affecting the overall optical signal transmission efficiency.

[0006] Therefore, the applicant proposes an on-chip optical amplifier and a method for preparing the same. Summary of the invention

[0007] The main purpose of the present application is to provide an on-chip optical amplifier and a preparation method thereof, aiming to solve the problems that the traditional erbium-doped fiber amplifier is too large and not conducive to integration, and the direct ion-doping of optical waveguides leads to crystal structure defects and optical transmission losses.

[0008] To achieve the above object, the present application provides an on-chip optical amplifier, comprising:

[0009] substrate;

[0010] An oxide layer, covering the substrate, for isolating and protecting the underlying layers;

[0011] A waveguide layer is located on the oxide layer, and a waveguide body is arranged in the central area of ​​the waveguide layer. A ridge-shaped or wedge-shaped structure is arranged protruding in the direction of the optical path extension outside the waveguide body, and its width gradually widens from the center to both sides, so as to optimize the transmission and amplification effect of the optical signal;

[0012] and a gain medium layer, which partially axially penetrates the embedded groove opened in the waveguide body to form a slit structure that concentrates the light field; wherein the gain medium layer includes: a doping layer, an intermediate layer and a doped medium layer, the number of the doping layers is at least 2, which are respectively located on both sides of the waveguide body and cooperate with the ridge-type or wedge-type structure to achieve bilateral amplification of the optical signal, the intermediate layer is contained in the slit structure in the center of the waveguide layer, and partially extends axially to the doping layers on both sides, and the doped medium layer fills the remaining space to further improve the optical performance of the overall structure.

[0013] Preferably, the refractive index of the doping layer is lower than the refractive index of the waveguide layer.

[0014] Preferably, the material of the doped dielectric layer is erbium-doped gain material.

[0015] As a preference, it also includes:

[0016] Pump light sources, at least two in number, are located on the side walls of both sides of the doping layer and are arranged opposite to the doping medium layer to provide energy required to activate doping ions in the doping layer;

[0017] Wherein, the wavelength of the pump light source matches the absorption characteristics of the doped medium layer.

[0018] Preferably, the doped medium layer is configured not to directly contact the pump light source, but to be separated from the optical waveguide core by a non-doped medium layer.

[0019] Preferably, both the ridge-shaped structure and the wedge-shaped structure can be arranged in a multi-layer stepped structure.

[0020] Preferably, the length of each layer of the step structure in the ridge-type structure and the wedge-type structure decreases layer by layer from top to bottom in a direction perpendicular to the upper surface of the substrate.

[0021] Preferably, the outer side walls of the ridge-shaped structure and the wedge-shaped structure are both curved or wavy structures, so as to reduce the scattering loss of the optical signal during transmission.

[0022] Preferably, an upper cladding layer is further provided on the waveguide layer to protect the waveguide layer from the influence of the external environment.

[0023] Preferably, the upper cladding layer is made of silicon dioxide or silicon nitride material.

[0024] To achieve the above object, the present application also provides a method for preparing an on-chip optical amplifier, comprising the following steps:

[0025] S1. forming an oxide layer on the substrate for isolating and protecting the underlying layer, wherein the oxide layer is made of silicon dioxide;

[0026] S2. forming a waveguide layer on the oxide layer and disposing a waveguide body in the central region of the waveguide layer;

[0027] S3. A ridge-shaped or wedge-shaped structure is formed in the direction of the optical path extending outside the waveguide body, and its width gradually widens from the center to both sides, for optimizing the transmission and amplification effect of the optical signal;

[0028] S4. An embedded groove is opened in the waveguide body and partially axially penetrates the gain medium layer to form a slit structure that concentrates the light field.

[0029] The present invention has the following beneficial effects:

[0030] First, by forming an oxide layer on the substrate, the underlying layers are effectively isolated and protected, ensuring the stability and long-term reliability of the device. Secondly, the design of the waveguide layer and the waveguide main structure therein optimize the transmission efficiency of the optical signal. At the same time, the introduction of the ridge or wedge structure further enhances the amplification effect. Furthermore, the special configuration of the gain medium layer improves the concentration of the light field, thereby improving the amplification efficiency. In addition, the setting of the pump light source and its wavelength match ensure efficient energy supply, thereby improving the efficiency of activating doped ions. Finally, the addition of the upper cladding layer not only protects the waveguide layer from the influence of the external environment, but also reduces the light loss at the interface, optimizing the overall optical performance of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1It is a schematic diagram of the structure of the on-chip optical amplifier;

[0032] Figure 2 is a cross-sectional schematic diagram of an on-chip optical amplifier in one embodiment;

[0033] Figure 3 is a cross-sectional schematic diagram of an on-chip optical amplifier in another embodiment;

[0034] Figure 4 is a side view of an on-chip optical amplifier in one embodiment;

[0035] Figure 5 FIG. 4 is a side view of an on-chip optical amplifier in another embodiment.

[0036] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0037] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0038] In addition, if the description of "first", "second", etc. is involved in this application, it is only used for descriptive purposes (such as for distinguishing the same or similar elements), and cannot be understood as indicating or suggesting its relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0039] See also Figures 1 to 5As shown, the on-chip optical amplifier comprises: a substrate 100, an oxide layer 200, a waveguide layer 300 and a gain medium layer 400. The oxide layer 200 covers the substrate 100 and is used to isolate and protect the underlying layers. The waveguide layer 300 is located on the oxide layer 200, and a waveguide body 301 is provided in the central area of ​​the waveguide layer 300. A ridge-shaped or wedge-shaped structure is provided protruding outward in the optical path extending direction outside the waveguide body 301, and its width gradually widens from the center to both sides, so as to optimize the transmission and amplification effect of the optical signal. The gain medium layer 400 partially axially penetrates the embedded groove 302 provided in the waveguide body 301, forming a slit structure for concentrating the optical field.

[0040] The gain medium layer 400 includes: a doped layer 401, an intermediate layer 402 and a doped medium layer 403. The number of the doped layers 401 is at least 2, which are respectively located on both sides of the waveguide body 301 and cooperate with the ridge-type or wedge-type structure to achieve bilateral amplification of the optical signal. The intermediate layer 402 is contained in the gap structure in the center of the waveguide layer 300 and partially extends axially to the doped layers 401 on both sides. The doped medium layer 403 is filled in the remaining space to further improve the optical performance of the overall structure.

[0041] In this embodiment, by integrating all necessary optical components, including the waveguide layer 300 and the gain medium layer 400, on a single substrate 100, miniaturization and high integration of the optical amplifier are achieved. At the same time, the ridge or wedge structure design in the waveguide layer 300 and the specific layout of the gain medium layer 400 work together to optimize the transmission characteristics and amplification effect of the optical signal.

[0042] Among them, the ridge or wedge structure helps to improve the coupling efficiency of optical signals and reduce transmission losses, while the bilateral amplification configuration enhances the signal amplification capability and provides more efficient and uniform optical gain.

[0043] In addition, the introduction of the doped medium layer 403 further improves the optical performance of the overall structure, and may improve the efficiency of the optical amplifier and the quality of the output optical signal by improving the light field distribution, reducing scattering and absorption, etc.

[0044] Compared with the prior art method of avoiding direct ion implantation into the optical waveguide by designing the ion doping layer 401, thereby reducing the defects of the crystal structure and the optical transmission loss, the present embodiment avoids the crystal structure defects that may be caused by direct ion doping by introducing the doped medium layer 403 and applying the non-doped intermediate layer 402 in the embedded groove 302, thereby reducing the optical transmission loss caused thereby. This design method not only optimizes the light field distribution and improves the amplification efficiency, but also improves the quality of the output optical signal by reducing scattering and absorption.

[0045] Specifically, when the optical signal propagates inside the waveguide body 301, due to the presence of the ridge or wedge structure, the evanescent wave effect of the optical signal is enhanced when propagating in the waveguide body 301, wherein the evanescent wave refers to a weak tail of light existing near the waveguide surface, which can interact with the surrounding medium. Furthermore, since the doping layer 401 is located on both sides of the waveguide body 301 and cooperates with the ridge or wedge structure, the evanescent wave can more effectively interact with the doped ions in the gain medium, thereby causing the optical signal to be gradually amplified during the propagation process, thereby achieving bilateral amplification of the optical signal. At the same time, through the non-doped intermediate layer 402 used in the embedded groove 302, the light field distribution is further optimized, and scattering and absorption are reduced, the light field is concentrated, and the interaction efficiency between light and doped ions is improved. The doped medium layer 403 filled in the remaining space is used to improve the light field distribution, reduce mode leakage, and effectively increase the effective refractive index contrast of the waveguide, thereby avoiding direct ion injection into the core area of ​​the waveguide.

[0046] In one embodiment, the refractive index of the doping layer 401 is lower than the refractive index of the waveguide layer 300 .

[0047] In this embodiment, the refractive index difference between the doping layer 401 and the waveguide layer 300 set as above can further enhance the guidance and localization of the optical signal in the waveguide body 301, thereby reducing the leakage and scattering loss of the signal. At the same time, it is also beneficial to improve the mode matching efficiency, so that the light energy can be better concentrated in the waveguide core for propagation, and the loss caused by mode mismatch is reduced.

[0048] In addition, by selecting a doping layer 401 material with a lower refractive index than the waveguide layer 300, a strong optical confinement effect can be formed at the waveguide interface to maintain a high transmission efficiency of the optical signal and enhance the waveguide's ability to manipulate the optical signal. For example, the optical signal in a curved waveguide can also be effectively guided, thereby achieving a high-density optical path layout in a miniaturized integrated photonic circuit.

[0049] In one embodiment, the material of the doped medium layer 403 is erbium-doped gain material.

[0050] Among them, the erbium-doped gain material includes but is not limited to erbium ions (Er3+), ytterbium ions (Yb3+), thulium ions (Tm3+), rubidium ions (Nd3+), praseodymium ions (Pr3+) or dysprosium ions (Dy3+).

[0051] In this embodiment, by using erbium-doped gain materials, efficient optical signal amplification can be achieved. Erbium elements, due to their unique energy level structure, can provide high gain amplification for 1550 nanometer wavelength optical signals, and this wavelength range just corresponds to the wavelength window with the lowest loss in optical communication systems.

[0052] Therefore, using erbium-doped materials as gain media can not only improve the responsiveness of the amplifier, but also achieve optimized optical amplification effects for key wavelengths in optical communications.

[0053] In addition, by optimizing the concentration and distribution of erbium-doped materials, a more uniform light field distribution can be formed in the waveguide, reducing scattering and absorption, and further improving the efficiency of the optical amplifier and the quality of the output optical signal.

[0054] In one of the embodiments, it also includes: a pump light source 404, the number of which is at least 2, and the pump light source 404 is located on the side walls of both sides of the doping layer 401, and is arranged opposite to the doping medium layer 403, for providing energy required to activate the doped ions in the doping layer 401.

[0055] The wavelength of the pump light source 404 matches the absorption characteristics of the doped medium layer 403 .

[0056] In this embodiment, at least two pump light sources 404 are provided on the side walls of both sides of the doping layer 401 and arranged opposite to the doping medium layer 403, so that the energy required to activate the doped ions in the doping layer 401 can be effectively provided. The wavelength of the pump light source 404 is carefully selected to match the absorption characteristics of the doping medium layer 403, ensuring the effective transfer and utilization of energy, and allowing the pump light to be uniformly irradiated on the doping layer 401, thereby promoting efficient amplification of the optical signal.

[0057] Secondly, using a pump light source 404 that matches the absorption characteristics of the doped medium layer 403 can maximize the pump efficiency because this can reduce the loss of pump energy while ensuring that the doped ions obtain sufficient energy to achieve stimulated emission.

[0058] For example, when the doped medium layer 403 is an erbium-doped material, the wavelength of the pump light source 404 is usually selected to be around 980 nanometers or 1480 nanometers. These two wavelengths are the peak positions of erbium ion absorption, thereby being able to efficiently activate erbium ions and amplify the 1550 nanometer wavelength signal light.

[0059] In addition, the above optimization of the number and position of the pump light sources 404 helps to achieve uniform pumping of the active ions in the doping layer 401, avoiding the gain non-uniformity caused by uneven pumping, thereby ensuring that the optical signal can obtain a consistent and stable amplification effect. The pump light sources 404 on both sides cooperate with each other, which is also conducive to forming a bidirectional symmetrical pumping mode, thereby further balancing and improving the optical performance of the overall device.

[0060] Furthermore, the doped medium layer 403 is configured not to directly contact the pump light source 404, but to be separated from the optical waveguide core by a non-doped medium layer.

[0061] Specifically, the non-doped medium layer acts as a buffer layer to optimize the propagation path of the pump light and reduce the loss of the pump light in the process of propagating to the doped medium layer 403. At the same time, it helps to protect the doped medium layer 403 from thermal effects or optical damage caused by direct contact with the pump light source 404, and can effectively utilize the pump light energy.

[0062] In addition, this non-direct contact design can more flexibly control the position and angle of the pump light source 404, thereby achieving precise adjustment of the pump light field distribution to obtain the best gain medium excitation effect.

[0063] In the specific operation process, the pump light emitted by the pump light source 404 first passes through the non-doped medium layer 403, and then enters the doped medium layer 403. At the same time, since the refractive index of the non-doped medium layer 403 can be designed to match the waveguide layer 300 and the doped medium layer 403, the reflection and scattering losses caused by the refractive index mismatch are reduced, and the pumping efficiency is improved.

[0064] Secondly, the absorption length of the pump light can be increased by selecting a suitable material for the non-doped dielectric layer 403, thereby further improving the pump efficiency and light amplification performance.

[0065] In the embodiments, both the ridge-shaped structure and the wedge-shaped structure can be arranged in a multi-layer stepped structure.

[0066] In this embodiment, the ridge structure and the wedge structure arranged in a multi-layer stepped structure can effectively enhance the interaction between the optical signal and the active ions in the doped medium layer 403 by gradually changing the effective refractive index of the waveguide, thereby improving the light amplification efficiency.

[0067] Furthermore, each of the multiple steps in the ridge and wedge structures can be optimized to provide specific optical functions, such as mode matching, light localization, or phase adjustment. For example, by properly designing the height and width of the steps, the desired phase change can be introduced into the waveguide, thereby improving the superposition effect of the optical signal and the pump light and enhancing the light amplification effect.

[0068] In addition, the multi-layer stepped structure can also be used to reduce reflection and scattering caused by differences in the refractive index of materials.

[0069] In the embodiments, the lengths of the stepped structures of the ridge-shaped structure and the wedge-shaped structure decrease layer by layer from top to bottom in a direction perpendicular to the upper surface of the substrate 100 .

[0070] In this embodiment, by reducing the length of the stepped structure layer by layer from top to bottom, the propagation path of the optical signal in the waveguide is effectively managed, thereby optimizing the interaction between light and doped ions and further improving the performance of the optical amplifier.

[0071] Specifically, by precisely controlling the length and width of each step, specific phase changes and mode conversions can be introduced during the propagation of optical signals. This allows the optical signal to be gradually concentrated and enhances the interaction with active doped ions, improving the efficiency of optical amplification. At the same time, it can also reduce interface reflection and scattering caused by differences in the refractive index of materials, reducing insertion loss.

[0072] In addition, the step-by-step structure can also help improve the flexibility and adjustability of the device. That is, in practical applications, the performance of the device can be optimized by changing the specific size of each step to adapt it to different operating conditions and requirements.

[0073] In one of the embodiments, the outer side walls of the ridge-shaped structure and the wedge-shaped structure are both curved or wavy structures, which are used to reduce the scattering loss of optical signals during transmission.

[0074] In this embodiment, by minimizing the surface area of ​​the optical waveguide structure, the interaction with the environment interface is reduced, thereby reducing scattering loss. This is crucial to improving the overall efficiency and performance of the optical amplifier, especially in optical communication systems that require long-distance transmission and high performance.

[0075] Specifically, curved or wavy outer sidewalls can be achieved through precise manufacturing processes, such as using grayscale lithography or nonlinear laser cutting methods, to control the morphology of the structure on the micrometer or nanometer scale to achieve optimal optical performance.

[0076] Among them, the curved or wavy design can also provide additional mechanical stability, helping the waveguide structure resist the impact of external environmental changes, such as temperature fluctuations or mechanical stress.

[0077] At the same time, it also helps to improve the coupling efficiency of pump light and signal light. That is, the outer wall with curved surface and wave shape can effectively disperse the pump light, so that it covers the doped medium layer 403 more evenly, thereby improving the pump efficiency and uniformity of light amplification. It ensures the efficient superposition of pump light and signal light in the waveguide, maximizes the activation of doped ions, and generates high-gain optical signals.

[0078] In one embodiment, an upper cladding layer 500 is further disposed on the waveguide layer 300 to protect the waveguide layer 300 from the influence of the external environment.

[0079] In this embodiment, the upper cladding layer 500 is provided to effectively isolate the waveguide layer 300 and the active doped medium layer 403, thereby preventing them from being affected by the external environment such as water vapor, pollutants or mechanical damage, thereby ensuring the stability and long-term reliability of the device. At the same time, the use of the upper cladding layer 500 can also improve the thermal management capability of the optical amplifier.

[0080] For example, the upper cladding layer 500 is usually made of a material with a high refractive index and excellent transparency, such as silicon dioxide or a high molecular polymer. Furthermore, the above material can not only provide physical protection, but also optically match the waveguide layer 300 and the doped medium layer 403 to reduce the light loss at the interface. And by precisely controlling the thickness and refractive index of the upper cladding layer 500, the propagation characteristics of the optical signal in the waveguide can be optimized, mode leakage can be reduced, and light localization can be improved.

[0081] Among them, silicon dioxide (SiO2) is a widely used insulating material and is very suitable as a cladding material in optoelectronic devices because it has high transparency, excellent chemical stability and good thermal stability. Its low refractive index can effectively limit the propagation of optical signals in waveguides, reduce mode leakage, and improve the localization of optical signals. In addition, the high thermal conductivity of silicon dioxide also helps to disperse heat and maintain the stability of optical amplifiers under long-term operation.

[0082] Silicon nitride (Si3N4) is also a material with excellent performance. It not only provides a higher refractive index than silicon dioxide, but also has better mechanical strength and corrosion resistance. This makes silicon nitride an ideal choice for improving the ability of optical amplifiers to withstand environmental influences. At the same time, the high thermal conductivity and excellent thermal expansion properties of silicon nitride ensure physical stability under temperature changes, which is crucial for maintaining optical performance in long-term operation.

[0083] In summary, by adopting these high-performance materials, the upper cladding layer 500 not only protects the waveguide layer 300 and the doped medium layer 403 from the external environment, but also improves the efficiency and reliability of the optical amplifier through optimized thermal management and optical properties.

[0084] In addition, the present application also provides a method for preparing an on-chip optical amplifier, comprising the following steps:

[0085] S1. forming an oxide layer 200 on the substrate 100 for isolating and protecting the underlying layer, wherein the oxide layer 200 is made of silicon dioxide;

[0086] S2. A waveguide layer 300 is formed on the oxide layer 200, and a waveguide body 301 is disposed in the central region of the waveguide layer 300;

[0087] S3. A ridge or wedge-shaped structure is formed in the direction of the optical path extending outside the waveguide body 301, and its width gradually widens from the center to both sides, for optimizing the transmission and amplification of optical signals;

[0088] S4. An embedded groove 302 is opened in the waveguide body 301 and partially axially penetrates the gain medium layer 400 to form a slit structure that concentrates the light field.

[0089] In this embodiment, the on-chip optical amplifier prepared by the above steps can effectively improve the transmission efficiency and amplification effect of the optical signal. Specifically, the formed ridge-type or wedge-type structure can enhance the interaction between the optical signal and the active ions in the doped medium layer 403, thereby improving the optical amplification efficiency. At the same time, the setting of the embedded groove 302 makes the light field more concentrated in the active area, further enhancing the amplification effect of the optical signal.

[0090] Furthermore, the method further comprises the following preferred steps:

[0091] S5. A pump light source 404 is arranged on both side walls of the doped medium layer 403 and is arranged opposite to the doped medium layer 403 to provide energy required to activate the doped ions; wherein the wavelength of the pump light source 404 matches the absorption characteristics of the doped medium layer 403 to maximize the pump efficiency.

[0092] S6. An upper cladding layer 500 is provided on the waveguide layer 300 to protect the waveguide layer 300 from the influence of the external environment; wherein the upper cladding layer 500 is made of silicon dioxide or silicon nitride material.

[0093] It should be noted that, in this document, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, device, article or on-chip optical amplifier preparation method including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, device, article or on-chip optical amplifier preparation method. In the absence of more restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, device, article or on-chip optical amplifier preparation method including the element.

[0094] The above description is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An on-chip optical amplifier, characterized in that include: A substrate (100); An oxide layer (200), covering the substrate (100) and used for isolating and protecting the underlying layers; A waveguide layer (300) is located on the oxide layer (200), and a waveguide body (301) is arranged in the central area of ​​the waveguide layer (300), and a ridge-shaped or wedge-shaped structure is arranged protruding in the direction of the optical path extension outside the waveguide body (301), and its width gradually widens from the center to both sides, so as to optimize the transmission and amplification effect of the optical signal; and a gain medium layer (400), part of which axially penetrates an embedded groove (302) opened in a waveguide body (301), forming a slit structure for concentrating a light field; wherein the gain medium layer (400) comprises: a doping layer (401), an intermediate layer (402) and a doping medium layer (403); the doping layers (401) are at least two in number, respectively located on both sides of the waveguide body (301), and cooperate with a ridge-type or wedge-type structure to achieve bilateral amplification of optical signals; the intermediate layer (402) is contained in the slit structure in the center of the waveguide layer (300), and part of which axially extends into the doping layers (401) on both sides; the doping medium layer (403) is filled in the remaining space, so as to further improve the optical performance of the overall structure.

2. The on-chip optical amplifier according to claim 1, characterized in that: The refractive index of the doping layer (401) is lower than the refractive index of the waveguide layer (300).

3. The on-chip optical amplifier according to claim 2, characterized in that: The material of the doped medium layer (403) is erbium-doped gain material.

4. The on-chip optical amplifier according to claim 3, characterized in that: Also includes: At least two pump light sources (404) are located on the side walls of both sides of the doping layer (401) and are arranged opposite to the doping medium layer (403) to provide energy required to activate doping ions in the doping layer (401); The wavelength of the pump light source (404) matches the absorption characteristics of the doped medium layer (403), and the doped medium layer (403) is configured not to directly contact the pump light source (404), but to be separated from the optical waveguide core by a non-doped medium layer.

5. The on-chip optical amplifier according to claim 1, characterized in that: Both the ridge-shaped structure and the wedge-shaped structure can be arranged in a multi-layer stepped structure.

6. The on-chip optical amplifier according to claim 5, characterized in that: The length of each layer of the step structure in the ridge-shaped structure and the wedge-shaped structure decreases layer by layer from top to bottom in a direction perpendicular to the upper surface of the substrate (100).

7. The on-chip optical amplifier according to claim 1, characterized in that: The outer side walls of the ridge-shaped structure and the wedge-shaped structure are both curved or wavy structures, which are used to reduce the scattering loss of optical signals during transmission.

8. The on-chip optical amplifier according to claim 1, characterized in that: An upper cladding layer (500) is also provided on the waveguide layer (300) to protect the waveguide layer (300) from the influence of the external environment.

9. The on-chip optical amplifier according to claim 8, characterized in that: The upper cladding layer (500) is made of silicon dioxide or silicon nitride material.

10. A method for preparing an on-chip optical amplifier, characterized in that: The following steps are involved: (S1) forming an oxide layer (200) on the substrate (100) for isolating and protecting the underlying layer; (S2) forming a waveguide layer (300) on the oxide layer (200), and disposing a waveguide body (301) in the central region of the waveguide layer (300); (S3) A ridge-shaped or wedge-shaped structure is formed in the direction of the optical path extending outside the waveguide body (301), and its width gradually widens from the center to both sides, for optimizing the transmission and amplification effect of the optical signal; (S4) An embedded groove (302) is provided in the waveguide body (301) and partially penetrates the gain medium layer (400) axially, thereby forming a slit structure for concentrating the light field.

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