On-chip integrated magneto-optical isolator

Abstract

An on-chip integrated magneto-optical isolator, comprising: an input waveguide array (20) used for inputting light of at least one wavelength; a magneto-optical isolator (30) connected to the input waveguide array (20) and used for implementing forward transmission and reverse isolation of light, wherein the magneto-optical isolator (30) comprises an arrayed waveguide grating (31), a magneto-optical film, and magnetic field applying devices (32), the magneto-optical film is located on a surface of the arrayed waveguide grating (31), the light of at least one wavelength propagates in the arrayed waveguide grating (31), and the magnetic field applying devices (32) are used for applying magnetic fields perpendicular to a light transmission direction of the arrayed waveguide grating (31); and an output waveguide array (40) connected to the magneto-optical isolator (30) and used for outputting light of at least one wavelength.

Description

On-chip integrated magneto-optical isolator

[0001] Related applications

[0002] This application claims priority to Chinese patent application number 202410031738.8, filed on January 9, 2024, entitled “On-chip integrated magneto-optical isolator,” the entire text of which is incorporated herein by reference. Technical Field

[0003] The present application relates to the technical field of silicon-based optoelectronic devices, and in particular to an on-chip integrated magneto-optical isolator. Background Art

[0004] On-chip integrated magneto-optical isolators are an essential component in the field of silicon-based optoelectronic devices. In optical transmission links, their unique unidirectional transmission property filters out reflected light caused by mode mismatches or waveguide roughness, significantly improving the stability of the entire link.

[0005] Optical isolators are commonly used in the backend of semiconductor lasers to protect the laser from reflected light in the link, thereby improving the laser's lifespan and the stability of the entire optical system. In multi-wavelength link applications, isolators often require a large bandwidth to achieve optical isolation between multiple waveguides. However, the bandwidth of current on-chip magneto-optical isolators based on Mach–Zehnder interferometer (MZI) configurations is still in the range of a few nanometers, making it difficult to meet the requirements for multi-wavelength multiplexing in broadband links.

[0006] Summary of the Invention

[0007] According to various embodiments of the present application, an on-chip integrated magneto-optical isolator is provided.

[0008] In a first aspect, an embodiment of the present application provides an on-chip integrated magneto-optical isolator, comprising:

[0009] an input waveguide array for inputting light of at least one wavelength;

[0010] A magneto-optical isolator connected to the incident waveguide array is used to achieve reverse isolation of forward light transmission; the magneto-optical isolator includes an arrayed waveguide grating, a magneto-optical film, and a magnetic field applying device; wherein the magneto-optical film is on the surface of the arrayed waveguide grating, the light of at least one wavelength propagates in the arrayed waveguide grating, and the magnetic field applying device is used to apply a magnetic field perpendicular to the light transmission direction of the arrayed waveguide grating;

[0011] The output waveguide array connected to the magneto-optical isolator is used to output light of all incident wavelengths.

[0012] In one embodiment, the arrayed waveguide grating includes a plurality of waveguides, and a plurality of magneto-optical waveguides are formed by depositing or bonding the magneto-optical film on each of the waveguides, and the length of each magneto-optical waveguide increases in multiples.

[0013] The magnetic field applying device is located on both sides of the arrayed waveguide grating and applies a magnetic field perpendicular to the light transmission direction of the multiple magneto-optical waveguides.

[0014] In one embodiment, the arrayed waveguide grating includes a plurality of waveguides, and the magneto-optical isolator further includes a transparent film, which is disposed on a surface of the arrayed waveguide grating, and has a refractive index that is the same as that of the magneto-optical film.

[0015] Taking the central waveguide of the arrayed waveguide grating as the axis of symmetry, the magneto-optical film is sequentially deposited or bonded onto each of the waveguides from the inside to the outside to form a plurality of magneto-optical waveguides, wherein the length of each magneto-optical film increases sequentially by multiples with the central waveguide as the axis of symmetry, and the transparent film is deposited or bonded onto each of the waveguides from the inside to the outside to form a plurality of magneto-optical waveguides, wherein the length of each transparent film decreases sequentially by multiples with the central waveguide as the axis of symmetry, and the total length of the magneto-optical film and the transparent film on each waveguide is equal;

[0016] The magnetic field applying device is located at the center of the arrayed waveguide grating, and applies two magnetic fields perpendicular to the light transmission directions of the multiple magneto-optical waveguides outwardly with the central waveguide as the symmetry axis.

[0017] In one embodiment, the arrayed waveguide grating includes a plurality of waveguides, and the magneto-optical isolator further includes a transparent film, which is disposed on a surface of the arrayed waveguide grating, and has a refractive index that is the same as that of the magneto-optical film.

[0018] Taking the central waveguide of the arrayed waveguide grating as the axis of symmetry, the magneto-optical film is sequentially deposited or bonded onto each of the waveguides from the inside to the outside to form a plurality of magneto-optical waveguides, wherein the length of each magneto-optical film increases sequentially by multiples with the central waveguide as the axis of symmetry, and the transparent film is deposited or bonded onto each of the waveguides from the inside to the outside to form a plurality of magneto-optical waveguides, wherein the length of each transparent film decreases sequentially by multiples with the central waveguide as the axis of symmetry, and the total length of the magneto-optical film and the transparent film on each waveguide is equal;

[0019] The magnetic field applying device is located on both sides of the arrayed waveguide grating and applies a magnetic field perpendicular to the light transmission direction of the multiple magneto-optical waveguides.

[0020] In one embodiment, the magneto-optical isolator further includes a first free transmission area unit and a second free transmission area unit. The light of at least one wavelength is input by the incident waveguide array, is transmitted through the first free transmission area unit, and is divided into multiple beams of light and enters the array waveguide grating. After being transmitted for a certain distance, the light enters the second free transmission area unit and is then output from the output waveguide array.

[0021] In one embodiment, the length of each waveguide in the arrayed waveguide grating satisfies a fixed length difference.

[0022] In one embodiment, the magneto-optical film includes but is not limited to rare earth doped yttrium iron garnet.

[0023] In one embodiment, the transparent film is made of a material whose light loss in the working band of the magneto-optical isolator is lower than a preset value, including but not limited to doped silicon nitride, chalcogenide glass, and polymer.

[0024] In one embodiment, the magnetic field applying device includes but is not limited to a permanent magnet and a charged coil.

[0025] In one embodiment, the magneto-optical isolator further includes a spectrometer, which is used to split the incident light into light of multiple wavelengths; wherein the input end of the spectrometer is used to receive the incident light, and the output end of the spectrometer is connected to the incident waveguide array, and is used to output the light of multiple wavelengths to the incident waveguide array.

[0026] The details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the disclosed drawings without any creative work.

[0028] FIG1 is a schematic diagram of an application environment of an on-chip integrated magneto-optical isolator according to an embodiment;

[0029] FIG2 is a schematic diagram of an on-chip integrated magneto-optical isolator according to an embodiment;

[0030] FIG3 is a schematic structural diagram of an on-chip integrated magneto-optical isolator in another embodiment;

[0031] FIG4 is a schematic structural diagram of an on-chip integrated magneto-optical isolator according to another embodiment;

[0032] FIG5 is a schematic structural diagram of an on-chip integrated magneto-optical isolator according to another embodiment;

[0033] FIG6 is a side view of a magneto-optical waveguide of a magneto-optical isolator in one embodiment;

[0034] 7 is a diagram showing the relationship between the non-reciprocal phase shift amount, insertion loss, and isolation of an on-chip integrated magneto-optical isolator in one embodiment;

[0035] FIG8 is a forward and reverse transmission curve of an on-chip integrated single-wavelength magneto-optical isolator according to an embodiment;

[0036] FIG9 is a forward and reverse transmission curve of an on-chip integrated four-wavelength magneto-optical isolator according to an embodiment;

[0037] FIG10 is a schematic structural diagram of an on-chip integrated magneto-optical isolator in another embodiment.

[0038] Among them, 102, laser; 104, optical isolator; 106, detector; 20, incident waveguide array; 30, magneto-optical isolator; 40, output waveguide array; 31, arrayed waveguide grating; 32, magnetic field application device; 50, spectrometer. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0040] In addition, it can be understood that although the efforts made in this development process may be complex and lengthy, for ordinary technicians in the field related to the contents disclosed in this application, some design, manufacturing or production changes based on the technical contents disclosed in this application are just conventional technical means and should not be understood as the contents disclosed in this application are insufficient.

[0041] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments unless there is a conflict.

[0042] Unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by a person of ordinary skill in the technical field to which this application belongs. The words "one", "a", "the" and the like used in this application do not indicate a limit on quantity and may indicate the singular or plural. The terms "include", "comprise", "have" and any variations thereof used in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units that are inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The word "multiple" used in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific order for the objects.

[0043] The on-chip integrated magneto-optical isolator provided in this application can be applied in the multi-wavelength link application environment as shown in FIG1. ​​The multi-wavelength link mainly comprises three parts. The first part is composed of an array of semiconductor lasers 102, and the output wavelengths of the laser array 102 are λ1, λ2, ..., λ N The N different wavelengths of light are coupled into the silicon photonic chip through the on-chip coupling structure; the second part is the optical isolator 104. After the N different wavelengths of light are input through one end of the optical isolator 104, they are converged into a single-channel output and transmitted to the detector 106.

[0044] An embodiment of the present application provides an on-chip integrated magneto-optical isolator, as shown in FIG2 . The on-chip integrated magneto-optical isolator includes, in sequence along the light transmission direction: an incident waveguide array 20 , a magneto-optical isolator 30 , and an output waveguide array 40 .

[0045] The incident waveguide array 20 is used to input light of at least one wavelength; the magneto-optical isolator 30 connected to the incident waveguide array 20 is used to realize the forward transmission and reverse isolation of light; the magneto-optical isolator 30 includes an arrayed waveguide grating 31, a magneto-optical film and a magnetic field applying device 32; wherein, the magneto-optical film is on the surface of the arrayed waveguide grating 31, the light of at least one wavelength propagates in the arrayed waveguide grating 31, and the magnetic field applying device 32 is used to apply a magnetic field perpendicular to the light transmission direction of the arrayed waveguide grating 31; the output waveguide array 40 connected to the magneto-optical isolator 30 is used to output the light of at least one wavelength.

[0046] The input waveguide array 20 consists of one or N waveguides and a cladding layer, and its structure should meet the conditions for supporting single-mode light transmission. The output waveguide array 40 consists of one or N waveguides and a cladding layer, and its structure should meet the conditions for supporting single-mode light transmission. The input waveguide array 20 and the output waveguide array 40 have the same waveguide core material and the same cladding material. The number of waveguides and geometric dimensions can be the same or different. The refractive index of the waveguide core material is greater than the refractive index of the cladding material.

[0047] The magneto-optical isolator in the embodiments of this application implements forward transmission and reverse isolation of light waves, thereby protecting the laser. Compared with related on-chip magneto-optical isolation, it can overcome the narrow application bandwidth of current on-chip integrated optical isolators. The magneto-optical isolator of this application can meet multi-wavelength application scenarios, such as multi-channel transmission technology in wavelength division multiplexing systems, and can expand its application bandwidth to within hundreds of nanometers. It can meet the application of links with wavelengths up to hundreds of nanometers, and has broad application prospects in wavelength division multiplexing system links.

[0048] In one embodiment, the arrayed waveguide grating includes a plurality of waveguides, and a plurality of magneto-optical waveguides are formed by depositing or bonding the magneto-optical film on each of the waveguides, and the length of each magneto-optical waveguide increases in multiples in sequence; the magnetic field application device is located on both sides of the arrayed waveguide grating, and applies a magnetic field perpendicular to the light transmission direction of the plurality of magneto-optical waveguides.

[0049] Specifically, the magneto-optical waveguide consists of a waveguide and a magneto-optical film located above the waveguide. The magneto-optical film and waveguide can be in direct contact or separated by a dielectric layer of a certain thickness. The thinner the dielectric layer, the better. As shown in Figure 3, the arrayed waveguide grating includes m waveguides. In the center region of the arrayed waveguide grating, a magneto-optical film material of a certain thickness is deposited / bonded above the waveguides and arranged according to a specific length. The length of the magneto-optical waveguides increases exponentially from bottom to top. For example, if the required minimum magneto-optical waveguide length is L1, the lengths of the m magneto-optical waveguides from bottom to top are L1, 2×L1, 3×L1, and m×L1, respectively. Under the action of an external unidirectional magnetic field, the waveguides can transmit light in the forward direction and isolate it in the reverse direction.

[0050] In one embodiment, the arrayed waveguide grating includes multiple waveguides, and the magneto-optical isolator also includes a transparent film, which is arranged on the surface of the arrayed waveguide grating, and the refractive index of the transparent film is the same as the refractive index of the magneto-optical film.

[0051] The distribution of magneto-optical film material within the arrayed waveguide grating (AWG) region is shown in Figure 4. The AWG comprises m waveguides. With the central waveguide of the AWG as the axis of symmetry, magneto-optical films are sequentially deposited or bonded onto each waveguide from the inside out to form multiple magneto-optical waveguides. The length of each magneto-optical film increases exponentially with the central waveguide as the axis of symmetry. Furthermore, transparent films are deposited or bonded onto each waveguide from the inside out to form a refractive index matching region. The length of each transparent film decreases exponentially with the central waveguide as the axis of symmetry. The total length of the magneto-optical film and transparent films on each waveguide is equal. A magnetic field application device is located at the center of the AWG and applies two magnetic fields, one upward and one downward, perpendicular to the optical transmission direction of the magneto-optical waveguides, with the central waveguide as the axis of symmetry.

[0052] Specifically, the central array waveguide is free of magneto-optical thin film material. The magneto-optical waveguides on either side of the central array waveguide have a length of L2. The lengths of the magneto-optical waveguides from the innermost to the outermost waveguides are L2, 2×L2, 3×L2, and so on. (m-1) / 2×L2. To achieve an integer multiple of the array waveguide phase difference, an additional material with the same refractive index as the magneto-optical thin film material is required. Within each array waveguide, the length of the refractive index-matching region should complement the magneto-optical waveguide length. Under the influence of an external push-pull magnetic field, forward transmission of light waves and reverse isolation are achieved.

[0053] In some embodiments, the refractive index of the transparent film material is equal to or close to that of the magneto-optical film material. The effective refractive indices of the magneto-optical waveguide and the index-matched waveguide should be equal to or close to each other. Effective refractive index matching between the two can be achieved by changing the refractive index or dimensions of the transparent film material, such as by changing the thickness of the transparent film material.

[0054] In one embodiment, in order to simplify the direction of applying the magnetic field, the distribution of the magneto-optical waveguide and the refractive index matching area can also be as shown in Figure 5, and the magnetic field application device is located on both sides of the arrayed waveguide grating, applying a magnetic field perpendicular to the light transmission direction of the multiple magneto-optical waveguides.

[0055] Figures 3 to 5 show the case of N input ports and 1 output port. In Figures 3 to 5, when there is no external magnetic field, the phase difference between the arrayed waveguides 1, 2...m is When a positive magnetic field is applied, the phase difference between the array waveguides 1, 2…m is When a reverse magnetic field is applied, the phase difference between the arrayed waveguides 1, 2…m is In other words, under a fixed magnetic field direction, during forward transmission (i.e., when light is input from the incident port and output from the output port), the phase difference between the array waveguides 1, 2…m is In reverse transmission (i.e. when light is input from the output port and output from the incident port), the phase difference between the array waveguides 1, 2…m is

[0056] Figure 6 shows a side view of the magneto-optical waveguide, where the applied magnetic field is perpendicular to the optical waveguide's propagation direction. When light propagates along the +z direction, the propagation constant of the magneto-optical waveguide is denoted as βf; when light propagates along the -z direction, the propagation constant of the magneto-optical waveguide is denoted as βb. The difference between the two propagation constants is denoted as NRPS, and is calculated as follows:

[0057] Where β is the propagation constant; ω is the optical frequency; ε0 is the vacuum dielectric constant; S is the energy flux in the direction of light propagation (z direction); γ is the off-diagonal element of the dielectric constant tensor of the magneto-optical material; n0 is the refractive index of the magneto-optical material; H x is the horizontal component of the magnetic field in the light field; is the partial differential in the vertical direction.

[0058] In one embodiment, the magneto-optical isolator further includes a first free transmission area unit and a second free transmission area unit. The light of at least one wavelength is input by the incident waveguide array, is transmitted through the first free transmission area unit, and is divided into multiple beams of light and enters the array waveguide grating. After being transmitted for a certain distance, the light enters the second free transmission area unit and is then output from the output waveguide array.

[0059] In one embodiment, the length of each waveguide in the arrayed waveguide grating satisfies a fixed length difference to satisfy a fixed phase difference.

[0060] In one embodiment, the magneto-optical film includes but is not limited to rare earth doped yttrium iron garnet.

[0061] In one embodiment, the transparent film is made of a material whose light loss in the working band of the magneto-optical isolator is lower than a preset value, including but not limited to doped silicon nitride, chalcogenide glass, and polymer.

[0062] In one embodiment, the input waveguide array is composed of one or more waveguides and a cladding layer, and the output waveguide array is composed of one or more waveguides and a cladding layer. The waveguide material may be, but is not limited to, silicon, silicon nitride, germanium, lithium niobate, chalcogenide glass, or other combinations. The cladding material may be, but is not limited to, silicon dioxide, silicon nitride, a polymer, or other combinations. The refractive index of the waveguide material must be greater than that of the cladding material. The magneto-optical film material is rare-earth-doped yttrium iron garnet, and the transparent film material may be any doped material with a mid-infrared loss below a preset value and a refractive index matching that of the magneto-optical film material, such as doped silicon nitride or chalcogenide glass. In some embodiments, the waveguide material is silicon nitride, and the cladding material is silicon dioxide. The waveguide type is not particularly limited and may be any suitable type. As non-limiting examples, the waveguide may be a rectangular waveguide, a ridge waveguide, or the like.

[0063] In one embodiment, the magnetic field applying device includes, but is not limited to, a permanent magnet and a charged coil. The applied magnetic field can be provided by a permanent magnet or by an induced magnetic field generated by a current-carrying conductor integrated on an optical chip. The magnetic field is required to magnetize the magneto-optical film material in-plane to a saturated state.

[0064] FIG7 provides an example simulation result of an on-chip integrated single-wavelength magneto-optical isolator of an embodiment of the present application. Taking the C-band application as an example, the width of the silicon nitride waveguide is 1000 nm and the thickness is 400 nm, the first free transmission region and the second free transmission region are in a confocal configuration or a Rowland configuration, the length of the first free transmission region or the second free transmission region (Free Propagation region, FPR) is 20.9 μm, and the number of array waveguides m=11. FIG7 shows the relationship between the non-reciprocal phase shift (horizontal axis) and the insertion loss (left axis of the vertical axis) and the isolation (right axis of the vertical axis) of the single-wavelength magneto-optical isolator device. The device insertion loss increases linearly with the increase of the non-reciprocal phase shift, and the device extinction ratio increases with the increase of the non-reciprocal phase shift, and tends to a stable value when the phase shift reaches about 60°. The device insertion loss mainly comes from the absorption loss of the magneto-optical thin film material in the near-infrared band. The magneto-optical thin film material used in the simulation is cerium-doped yttrium iron garnet (Ce:YIG), which exhibits a magneto-optical Faraday rotation angle of 5900° / cm and an optical loss of 137 dB / cm at a wavelength of 1550 nm. Figure 7 shows that when the extinction ratio is 30 dB, the required nonreciprocal phase shift is 50°, resulting in an overall device insertion loss of 2 dB.

[0065] Figure 8 provides the forward transmission curve and reverse transmission curve of the on-chip integrated single-wavelength magneto-optical isolator of an embodiment of the present application. At a wavelength of 1551nm, the transmittance of the device during forward transmission is -1.98dB, and the transmittance during reverse transmission is -31.1dB, thereby achieving the forward passage of light and reverse isolation.

[0066] FIG9 provides exemplary simulation results of an on-chip integrated multi-wavelength magneto-optical isolator according to an embodiment of the present application. Taking the C-band application as an example, the wavelengths are λ1 = 1512 nm, λ2 = 1532 nm, λ3 = 1552 nm, and λ4 = 1572 nm, respectively. The transmittances during forward transmission are -3.4 dB, -1.1 dB, -1.3 dB, and -3.3 dB, respectively, and the transmittances during reverse transmission are -12.0 dB, -9.6 dB, -8.7 dB, and -3.3 dB, thereby achieving the forward transmission and reverse isolation of light under multi-wavelength conditions. The insertion loss and extinction ratio here do not represent the final performance of the device. The improvement of the extinction ratio and the non-uniformity of the insertion loss can be achieved by further optimizing the number of arrayed waveguides, the length of the FPR, the arrayed waveguide spacing, and other parameters in the magneto-optical isolator. FIG8 and FIG9 are only illustrated using the example of the number of arrayed waveguides m = 11.

[0067] In one embodiment, as shown in FIG10 , the magneto-optical isolator further includes a spectrometer 50, which is used to split the incident light into light of multiple wavelengths; wherein the input end of the spectrometer 50 is used to receive the incident light, and the output end of the spectrometer 50 is connected to the incident waveguide array 20, for outputting the light of multiple wavelengths to the incident waveguide array 20.

[0068] The on-chip integrated magneto-optical isolator of this application can be used in conjunction with a spectrometer 50 to form a broadband magneto-optical isolator with a single input waveguide. FIG10 illustrates only one structure of a spectrometer 50. The spectrometer 50 of this application includes, but is not limited to, arrayed waveguide gratings, step gratings, and other structures. The number of waveguides n in the spectrometer 50 can be the same as or different from the number of waveguides m in the on-chip integrated magneto-optical isolator.

[0069] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0070] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. An on-chip integrated magneto-optical isolator, characterized in that, Comprising: An incident waveguide array for inputting light of at least one wavelength; A magneto - optical isolator connected to the incident waveguide array for realizing forward transmission and reverse isolation of light; The magneto - optical isolator includes an arrayed waveguide grating, a magneto - optical thin film, and a magnetic field applying device; wherein, the magneto - optical thin film is on the surface of the arrayed waveguide grating, the light of at least one wavelength propagates in the arrayed waveguide grating, and the magnetic field applying device is used to apply a magnetic field perpendicular to the light transmission direction of the arrayed waveguide grating; An output waveguide array connected to the magneto - optical isolator for outputting the light of at least one wavelength.

2. The on-chip integrated magneto-optical isolator according to claim 1, wherein, The arrayed waveguide grating includes multiple waveguides, and multiple magneto - optical waveguides are formed by depositing or bonding the magneto - optical thin film on each of the waveguides, and the lengths of the magneto - optical waveguides increase successively in multiples; The magnetic field applying device is located on both sides of the arrayed waveguide grating and applies a magnetic field perpendicular to the light transmission direction of the multiple magneto - optical waveguides.

3. The on-chip integrated magneto-optical isolator according to claim 1, wherein, The arrayed waveguide grating includes multiple waveguides, and the magneto - optical isolator further includes a transparent thin film. The transparent thin film is on the surface of the arrayed waveguide grating, and the refractive index of the transparent thin film is the same as that of the magneto - optical thin film; Taking the central waveguide of the arrayed waveguide grating as the symmetry axis, the magneto - optical thin film is deposited or bonded on each waveguide successively from the inside to the outside to form multiple magneto - optical waveguides. The lengths of the magneto - optical thin films increase successively in multiples with the central waveguide as the symmetry axis, and the transparent thin film is deposited or bonded on each waveguide from the inside to the outside. The lengths of the transparent thin films decrease successively in multiples with the central waveguide as the symmetry axis, and the total lengths of the magneto - optical thin film and the transparent thin film on each waveguide are equal; The magnetic field applying device is located at the center of the arrayed waveguide grating and applies two magnetic fields perpendicular to the light transmission direction of the multiple magneto - optical waveguides outward with the central waveguide as the symmetry axis.

4. The on-chip integrated magneto-optical isolator according to claim 1, wherein, The arrayed waveguide grating includes multiple waveguides, and the magneto - optical isolator further includes a transparent thin film. The transparent thin film is on the surface of the arrayed waveguide grating, and the refractive index of the transparent thin film is the same as that of the magneto - optical thin film; Taking the central waveguide of the arrayed waveguide grating as the symmetry axis, the magneto - optical thin film is deposited or bonded on each waveguide successively from the inside to the outside to form multiple magneto - optical waveguides. The lengths of the magneto - optical thin films increase successively in multiples with the central waveguide as the symmetry axis, and the transparent thin film is deposited or bonded on each waveguide from the inside to the outside. The lengths of the transparent thin films decrease successively in multiples with the central waveguide as the symmetry axis, and the magneto - optical thin film and the transparent thin film on each waveguide have equal total lengths; The magnetic field applying device is located on both sides of the arrayed waveguide grating and applies a magnetic field perpendicular to the light transmission direction of the multiple magneto - optical waveguides.

5. The on-chip integrated magneto-optical isolator according to claim 1, wherein, The magneto-optical isolator further includes a first free transmission region unit and a second free transmission region unit. The light of at least one wavelength is input by the incident waveguide array, and after being transmitted by the first free transmission region unit, it is divided into multiple beams of light and enters the arrayed waveguide grating. After being transmitted for a certain distance, it enters the second free transmission region unit and is output from the output waveguide array.

6. The on-chip integrated magneto-optical isolator according to claim 1, wherein, The lengths of the waveguides in the arrayed waveguide grating satisfy a fixed length difference.

7. The on-chip integrated magneto-optical isolator according to claim 1, wherein, The magneto-optical thin film includes, but is not limited to, rare earth-doped yttrium iron garnet.

8. The on-chip integrated magneto-optical isolator according to claim 3 or 4, wherein, The transparent thin film is a material with low loss for light in the working band of the magneto-optical isolator, including, but not limited to, silicon nitride, chalcogenide glass, and polymer.

9. The on-chip integrated magneto-optical isolator according to claim 1, wherein, The magnetic field application device includes, but is not limited to, a permanent magnet and a charged coil.

10. The on-chip integrated magneto-optical isolator according to any one of claims 1 to 9, wherein The magneto-optical isolator further includes a beam splitting device, which is used to split the incident light into lights of multiple wavelengths; wherein, the input end of the beam splitting device is used to receive the incident light, and the output end of the beam splitting device is connected to the incident waveguide array and is used to output the lights of multiple wavelengths to the incident waveguide array.

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