An electro-optically tunable device and communication system

Abstract

The application provides an electro-optically adjustable device and a communication system, the device comprising: a waveguide, a first grating, and an electrode pair, wherein the waveguide is configured to transmit N wavelength signal lights; the first grating comprises M different periods and is configured to select M wavelength signal lights from the N wavelength signal lights; and the electrode pair is configured to modulate the M wavelength signal lights, wherein M and N are integers greater than 1. The device provided by the application realizes independent adjustment of multiple wavelength signal lights through the grating with varying periods.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to an electro-optically tunable device and communication system. Background Technology

[0002] With the continuous emergence and popularization of emerging services such as 5G, IoT, big data, and cloud computing, the rapidly increasing data transmission volume places increasingly higher demands on the bandwidth of optical communication. The modulator of the transmitter in an optical communication system is responsible for converting electrical signals into optical signals; it is one of the most critical components of the system and also a major factor affecting its bandwidth.

[0003] High-capacity optical fiber communication systems are based on wavelength division multiplexing (WDM) technology. WDM allows dozens or even hundreds of optical channels to exist in a single optical fiber. Different wavelength channels carry different information, thereby increasing the data transmission rate of a single optical fiber.

[0004] To load different information onto multiple optical wavelength channels, a modulator with the same number of wavelength channels is required, thus increasing the cost and size of the transmitter.

[0005] How to achieve independent adjustment of multiple wavelengths by a single modulator, thereby improving the efficiency of the electrical signal to optical signal conversion process and thus improving the performance of the optical communication system, is an urgent problem to be solved. Summary of the Invention

[0006] This application provides an electro-optically tunable device and communication system capable of independently adjusting multiple wavelength signal lights.

[0007] In a first aspect, an electro-optically tunable device is provided, comprising: a waveguide, a first grating, and an electrode pair, wherein the waveguide is used to transmit signal light of N wavelengths; the first grating includes M different periods for selecting part or all of the signal light of the N wavelengths; and the electrode pair is used to modulate the signal light of the M wavelengths, wherein M and N are integers greater than 1.

[0008] It should be noted that the relationship between M and N is not limited in the scheme of this application; M can be less than N, equal to N, or greater than N. When M is less than N, the M periods of the first grating can be used to select some, but not all, of the N wavelength signal lights. When M is equal to N or greater than N, the M periods of the first grating can be used to select all of the N wavelength signal lights, or the M periods of the first grating can be used to select some, but not all, of the N wavelength signal lights. It should be understood that when the M periods of the first grating are used to select some, but not all, of the N wavelength signal lights, it indicates that at least one period of the M periods of the first grating corresponds to at least one of the N wavelength signal lights, that is, at least one period of the M periods of the first grating has a selective effect on at least one wavelength of the N wavelength signal lights, for example, exhibiting the Bragg effect. Since the M periods are different, the wavelengths of the at least one signal light among the selected N signal lights are also different.

[0009] Optionally, when M is greater than N, since the other periods besides the N periods of the first grating may not be used for wavelength selection, the other periods besides the N periods may be the same or different.

[0010] Optionally, in the scheme of this application, the electrode pair may include at least one pair, which is used to load an electrical signal into the optical channel to realize electro-optic conversion.

[0011] Based on the above scheme, this application selects a specific wavelength signal light by setting a grating with a changing period, and modulates the selected signal light using an electrode pair. It is suitable for independently modulating a certain wavelength signal in a multi-wavelength signal system, which can save the size and cost of the device and improve the efficiency of the electrical signal to optical signal conversion process.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, the first grating is located on or above the sidewall of the waveguide, and the distance between the first grating and the waveguide is greater than or equal to 0.

[0013] It should be understood that the first grating can be formed on the sidewall or above the waveguide by incomplete etching, or it can be placed as an independent element on the sidewall or above the waveguide. In this case, the distance between the first grating and the waveguide should meet certain distance requirements, such as being within a wavelength.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, the apparatus further includes: a second grating comprising M different periods for jointly selecting the M wavelengths of signal light with the first grating.

[0015] In conjunction with the first aspect, in some implementations of the first aspect, the second grating and the first grating are located on different sides of the waveguide, or the second grating and the first grating are located together above the waveguide, wherein the period of the second grating at the same position along the extension direction of the waveguide has a period difference from the period of the first grating.

[0016] Based on the above solution, the electro-optically adjustable device provided in this application, combined with the period difference between gratings, improves the ability of the gratings to select signal light and enhances the accuracy of the system.

[0017] In conjunction with the first aspect, in some implementations of the first aspect, the period difference at all locations along the extension direction of the waveguide is a constant.

[0018] It should be understood that there may be errors in the actual grating period during processing. When the period difference at the same position of the first and second gratings meets a certain accuracy requirement range, the period difference can be regarded as a constant value.

[0019] In conjunction with the first aspect, in some implementations of the first aspect, the number of electrode pairs is K, and the K electrode pairs share the same electrode in each electrode pair.

[0020] It should be understood that the relationship between K and N is not limited in the scheme of this application; K can be less than N, equal to N, or greater than N. When K is less than N, the K electrode pairs can be used to modulate K different wavelength signal lights selected by the grating. When K is equal to N, if N different wavelength signal lights are selected, the K electrode pairs can be used to modulate N signal lights simultaneously. When K is greater than N, the device has the ability to modulate K different wavelength signal lights.

[0021] In conjunction with the first aspect, in some implementations of the first aspect, the waveguide material includes the semiconductor material silicon, and the regions of the waveguide near the electrode pair are respectively P-type doped and N-type doped.

[0022] Based on the above scheme, the electro-optic conversion efficiency of the electro-optic tunable device can be further improved by using P-type doped and N-type doped waveguide materials.

[0023] In conjunction with the first aspect, in some implementations of the first aspect, the waveguide material includes materials with linear electro-optic effects, such as lithium niobate.

[0024] In conjunction with the first aspect, in some implementations of the first aspect, the waveguide shape includes an S-shaped structure.

[0025] Based on the above scheme, the size of the electro-optic tunable device can be further reduced by using an S-shaped waveguide.

[0026] In a second aspect, a communication system is provided, comprising: a transmitter including the device provided in the first aspect and outputting a first optical signal; a transmission medium for transmitting the first optical signal output by the transmitter; and a receiver for converting the first optical signal into a first electrical signal. Attached Figure Description

[0027] Figure 1 A schematic diagram of a typical WDM optical communication system is shown.

[0028] Figure 2 A schematic diagram of a modulator based on an MZ interferometer structure is shown.

[0029] Figure 3 A schematic diagram of a modulator based on a microring resonator structure and a schematic diagram of the transmission spectrum of the microring resonator are shown.

[0030] Figure 4 A schematic diagram of a transmitter 400 of a WDM optical communication system provided in an embodiment of this application is shown.

[0031] Figure 5 A schematic diagram of a transmitter 500 of a WDM optical communication system provided in an embodiment of this application is shown.

[0032] Figure 6 A schematic diagram of an electro-optically adjustable device 600 provided in an embodiment of this application is shown.

[0033] Figure 7 The diagram shows a schematic representation of an electro-optically adjustable device 700 provided in an embodiment of this application.

[0034] Figure 8 The diagram shows a schematic diagram of an electro-optically adjustable device 800 provided in an embodiment of this application.

[0035] Figure 9 This application illustrates a grating period variation method provided by an embodiment of the present application.

[0036] Figure 10 The modulation effect of the electro-optically tunable device based on the embodiments of this application on the wavelength and the modulation result of the modulator of the resonant cavity structure are shown.

[0037] Figure 11 The modulation effect of the electro-optically tunable device provided in the embodiments of this application on the wavelength.

[0038] Figure 12The transmission and reflection spectra provided in the embodiments of this application at different device lengths are shown.

[0039] Figure 13 The diagram shows the change in transmission spectrum caused by applying an electric field to a section of the waveguide of the device according to an embodiment of this application.

[0040] Figure 14 An embodiment of the present application provides a waveguide structure.

[0041] Figure 15 The diagram shows the structural schematics of four types of gratings provided in the embodiments of this application.

[0042] Figure 16 This illustration shows a schematic diagram of a grating structure formed by varying the waveguide thickness, according to an embodiment of this application.

[0043] Figure 17 An embodiment of the present application provides a waveguide structure. Detailed Implementation

[0044] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0045] The ever-increasing demand for fiber optic bandwidth is driving the development and application of optical communication systems. A typical optical communication system generally consists of three main parts: a transmitter, a transmission medium, and a receiver. The transmitter converts electrical signals into optical signals and outputs them. The output optical signals are transmitted through the transmission medium and received by the receiver, which then converts the received optical signals back into electrical signals. Within the transmitter, the device responsible for converting electrical signals into optical signals is the modulator. The modulator is one of the most crucial components in an optical communication system, and it should have a sufficiently wide modulation bandwidth to transmit information efficiently and without distortion.

[0046] Currently, high-capacity optical fiber communication systems are based on wavelength division multiplexing (WDM), which loads different information into multiple optical channels of different wavelengths, and transmits multiple wavelength optical signals in the same optical fiber, thereby increasing the data transmission rate of a single optical fiber. Figure 1 A schematic diagram of a typical WDM optical communication system is shown, in which... Figure 1 In the optical communication system shown, for each specific wavelength optical channel, i.e., the different light waves generated by each laser module in the transmitter, the transmitter needs to be configured with a corresponding modulator to load the electrical signal in the electronic chip onto the specific pre-designed light waves of the above-mentioned different wavelengths.

[0047] For example, the most commonly used modulator based on the Mach-Zehnder (MZ) interferometer structure is illustrated in the following diagram. Figure 2 As shown, when the optical signal enters the electro-optic modulator through the optical input terminal, it is split into two parts by a 1x2 beam splitter and guided to the two arms of the MZ interferometer. In at least one arm of the MZ interferometer, the refractive index of the waveguide changes with the electrical signal of the electrode, causing the phase of the optical signal in that arm to change accordingly. Thus, the phase difference between the two arms changes. Subsequently, the optical signals from the two arms of the MZ interferometer are combined by a 2x1 beam combiner, and the two optical signals interfere with each other. This causes the characteristics of the combined optical signal to change compared to the optical signal at the optical input terminal, such as in terms of optical intensity or optical phase. The modulated optical signal is then output from the optical output terminal.

[0048] However, for modulators based on the MZ interferometer structure, since the modulator has a relatively flat wavelength response, that is, the response to different wavelength channels is consistent in the WDM system, it is difficult to use a single MZ modulator to achieve the purpose of independently adjusting signals of multiple wavelengths. If you want to achieve independent adjustment of signals of multiple wavelengths, you need to use an MZ modulator with the same number of wavelength channels, which will lead to an increase in cost.

[0049] In addition, there is a modulator based on a micro-ring resonant cavity structure, the schematic diagram of which can be found in the reference. Figure 3 As shown in 3(a), the optical signal can be coupled from the transmission waveguide to the microring resonator via evanescent wave coupling. A waveguide exists within the microring resonator, and the refractive index of this waveguide changes with the electrical signal of the electrodes, causing the phase of the optical signal to change accordingly. Therefore, the resonant wavelength of the microring resonator shifts, thereby altering the characteristics of the output optical signal.

[0050] Output spectrum of the micro-ring resonator Figure 3 In (b), the wavelength spacing between different resonant wavelengths is the free spectral range (FSR). When the microring resonance condition changes, the FSR remains unchanged, meaning that multiple resonant wavelengths shift together as a whole. In other words, when a modulation signal is applied, several adjacent resonant wavelengths move together, which can easily cause crosstalk to other WDM wavelength channels. Therefore, it is difficult to use a single modulator to achieve the purpose of independently adjusting signals of multiple wavelengths. In order to achieve the adjustment of signals of multiple wavelengths, a microring modulator with the same number of wavelength channels is required.

[0051] In summary, for WDM systems, neither MZ modulators nor micro-ring modulators can independently modulate optical signals across multiple wavelength channels using a single modulator. That is, to load information onto different optical wavelengths, a modulator equal to the number of wavelength channels is required, leading to increased transmitter cost and size.

[0052] To address the aforementioned issues, this application provides an electro-optic tunable device. Based on a grating waveguide structure, it uses multiple pairs of electrodes located on both sides of the waveguide to control the resonant wavelength corresponding to the waveguide region. This eliminates the need for multiple tunable devices, enabling independent adjustment of multiple wavelengths within a single electro-optic tunable device. This facilitates efficient on-chip multi-wavelength optical signal processing and offers high adjustment efficiency.

[0053] The electro-optically tunable device provided in this application embodiment can be applied to the transmitter in a WDM optical communication system, such as... Figure 4 As shown, the Figure 4 A schematic diagram of a transmitter 400 of a WDM optical communication system provided in an embodiment of this application is shown. Figure 4 In the process, after light of multiple wavelengths enters the electro-optic tunable device 403, the electro-optic tunable device 403 independently modulates the optical signal of each wavelength channel and outputs the WDM optical signal.

[0054] Optionally, the electro-optically tunable device provided in this application embodiment can be applied to the transmitter in another WDM optical communication system, for example, Figure 5 The diagram shown illustrates a transmitter 500 of another WDM optical communication system provided in this application embodiment. Compared to Figure 4 ,exist Figure 5 In this process, light of multiple wavelengths is generated by a laser group 502, which includes multiple single-wavelength lasers. The light of multiple wavelengths output by the lasers is coupled together by a multiplexer 503 and transmitted through an optical fiber into an electro-optic tunable device 504. After the electro-optic tunable device 504 independently modulates the optical signal of each wavelength channel, a WDM optical signal is output.

[0055] It should be noted that the electro-optic tunable device provided in this application can also be applied to other scenarios that require the conversion of electrical signals to optical signals, such as multi-wavelength electro-optic switches, tunable filters, and electric field sensors.

[0056] The various embodiments provided in this application will now be described in detail with reference to the accompanying drawings.

[0057] The following description is provided to facilitate understanding of the embodiments of this application.

[0058] In the embodiments shown below, the terms "first," "second," "third," "fourth," and various numerical designations are merely for descriptive convenience and are not intended to describe a specific order or sequence, nor are they used to limit the scope of the embodiments of this application. For example, they may be used to distinguish different electrode pairs and optical signals.

[0059] Second, the terms “comprising” and “having” and any variations thereof in the embodiments of this application shown below are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products or devices.

[0060] In addition, the following text Figure 6 , Figure 7 , Figure 8 , Figure 14 , Figure 16 as well as Figure 17 These are all schematic diagrams taken from a top-down perspective.

[0061] Figure 6 This is a schematic diagram of an electro-optically adjustable device 600 according to an embodiment of this application. Figure 6 As shown, the electro-optically adjustable device 600 includes:

[0062] The waveguide 601, the first grating 602, and K electrode pairs 603. The K electrode pairs include the first electrode pair, the second electrode pair, up to the Kth electrode pair, where K is an integer greater than 1.

[0063] Specifically, the waveguide 601 is used to transmit light of N wavelengths, which carries N optical signals. The light of N wavelengths carrying N optical signals is input from the input end of the waveguide 601, which extends in the X direction, that is, the light of N wavelengths carrying N optical signals propagates along the X-axis.

[0064] It should be understood that the light of these N wavelengths is transmitted in the waveguide through the principle of total internal reflection. This principle can be found in the description of current related technologies, and will not be elaborated upon here.

[0065] The waveguide 601 can be made of a material with a linear electro-optic effect, or an electro-optically tunable or thermo-optically tunable material. This material allows the effective refractive index of the waveguide mode to vary with changes in the electric field, carrier concentration, or temperature in the waveguide region. For example, the waveguide 601 can be made of lithium niobate, silicon, silicon nitride, barium titanate, or an electro-optic polymer.

[0066] The first grating 602 includes M different periods, where M is an integer greater than or equal to 1. The first grating 602 with M different periods can be used to select M wavelengths of signal light from N wavelengths of signal light.

[0067] It should be understood that when light of N wavelengths propagates in waveguide 601, the first grating 602 will affect the optical signal propagated in waveguide 601, such as Bragg reflection. This effect allows M signal lights corresponding to M periods of the first grating 602 among the N wavelength optical signals to produce a resonance effect after being reflected back and forth in waveguide 601. That is, when the reflection of M specific wavelength optical signals corresponding to M periods meets the Bragg condition, these M optical signals are reflected by the grating, while other wavelength signals are basically not reflected. Thus, the first grating 602 can select the wavelengths of the signal light corresponding to the M periods, thereby producing a resonance effect. Figure 10 The spectrum shown in (a).

[0068] It should be understood that when M equals N, if the M periods are the periods corresponding to N wavelengths, that is, the periods that can produce the Bragg effect on the N wavelength signal light are all included in the first grating 602, the first grating 602 can select the input N wavelength signal light.

[0069] It should be noted that one implementation of forming the first grating 602 can be as follows: Figure 15 As shown, the refractive index of the waveguide material is changed periodically, for example, by doping.

[0070] In another possible implementation, the dimensions of waveguide 601 are periodically changed along the transmission direction of waveguide 601. In this case, incomplete etching can be performed on the outer wall or the inner wall of waveguide 601 to form the first grating 602.

[0071] This may include periodically changing the thickness of waveguide 601, such as... Figure 16 The grating shown.

[0072] Alternatively, in another possible implementation, forming the first grating 602 can be a periodic truncation of the waveguide.

[0073] Alternatively, in another possible implementation, the first grating 602 can be formed by periodically perforating the waveguide, or by other methods. This application is not limited to these methods. Figure 15 As shown in the diagram.

[0074] It should be noted that the first grating 602 can be placed on the inner wall or outer wall of the waveguide 601, or it can be placed above the waveguide 601. A schematic diagram of the first grating 602 placed above the waveguide 601 can be found in [reference needed]. Figure 16 ,exist Figure 16The first and second gratings are located above the waveguide. It should be understood that the distance between the first grating 602 and the waveguide 601 should satisfy a preset range, which can be on the order of wavelengths, for example, a range of one wavelength. Alternatively, the first grating 602 can be formed by etching at a corresponding position on the waveguide.

[0075] K electrode pairs 603 are arranged along the transmission direction of waveguide 601. For each of these K electrode pairs, the two electrodes are located on opposite sides of the outer wall of waveguide 601, i.e., placed perpendicular to the transmission direction of waveguide 601. When the first grating 602 is located on the outer wall of waveguide 601, each electrode pair is located outside the first grating 602. Each of the K electrode pairs 603 is responsible for acting on a segment of the waveguide between them, for example, by applying an electric field, injecting charge carriers, or heating, thereby changing the refractive index of that segment of waveguide 601 and thus affecting the characteristics of the output signal light. The material of the K electrode pairs 603 can be metal, transparent conductive oxide, etc.

[0076] Specifically, K can be equal to 1. When K is equal to 1, the single electrode pair can be used to modulate one of the N wavelengths. When K is equal to N, the N electrode pairs can be used to modulate each of the N wavelengths independently.

[0077] It should be noted that when the electro-optic adjustable device 600 needs to independently adjust the input signal light of a certain wavelength, a voltage can be applied to the electrode pair used to adjust the wavelength. At this time, the effective refractive index of the waveguide 601 within the range of the electrode pair changes, causing the peak of the wavelength selected by the corresponding grating within the range of the electrode pair to shift, thereby achieving the purpose of independently adjusting the signal light of that wavelength.

[0078] Based on the electro-optically tunable device proposed in this application, when adjusting multiple wavelength optical signals, it overcomes the drawback of requiring multiple independent modulators, achieving the effect of independent adjustment of multiple wavelengths of light by a single device. The structure is simple, saving cost and device size. Based on a grating structure with a varying period, it can independently adjust multiple wavelengths of input signal light, achieving high adjustment efficiency by utilizing the optical resonance effect.

[0079] Figure 7 This is a schematic diagram of an electro-optically adjustable device 700 according to an embodiment of this application. Figure 7 As shown, the electro-optically adjustable device 700 includes:

[0080] The waveguide 701, M gratings 702, and K electrode pairs 703 are provided. The M gratings 702 include a first grating, a second grating, and so on up to the Mth grating, and the K electrode pairs include a first electrode pair, a second electrode pair, and so on up to the Kth electrode pair, where M, N, and K are all integers greater than 1.

[0081] Specifically, in Figure 7 In the process, signal light of N wavelengths is input at the input end of waveguide 701, and the signal light of N wavelengths is transmitted along the transmission direction of waveguide 701, that is, the X-axis.

[0082] It should be understood that the light of these N wavelengths is transmitted in the waveguide through the principle of total internal reflection. This principle can be found in the description of current related technologies, and will not be elaborated upon here.

[0083] The waveguide 701 can be made of an electro-optic or thermo-optic tunable material, which allows the effective refractive index of the waveguide mode to vary with changes in the electric field, carrier concentration, or temperature in the region where the waveguide 701 is located. For example, the waveguide 701 can be made of lithium niobate, silicon, silicon nitride, barium titanate, or an electro-optic polymer.

[0084] M gratings 702 are used to select signal light of M wavelengths at specific wavelength positions. Specifically, the M gratings 702 include a first grating, a second grating, and so on up to the Mth grating. Each of the M gratings may include at least one period, that is, the number of periods in each grating may be one or more. It should be understood that the number of periods included in each grating may be different or the same.

[0085] It should be understood that the relationship between M and N is not limited in the scheme of this application; M can be less than N, equal to N, or greater than N. When M is less than N, the M periods of the first grating are used to select some, but not all, of the N wavelength signal lights. When M is equal to or greater than N, the M periods of the first grating are used to select all of the N wavelength signal lights.

[0086] Furthermore, in this application, the relationship between K and N is not limited; K can be less than N, equal to N, or greater than N. When K is less than N, the K electrode pairs can be used to modulate K different wavelength signal lights selected by the grating. When K is equal to N, if N different wavelength signal lights are selected, the K electrode pairs can be used to modulate N signal lights simultaneously. When K is greater than N, the device has the ability to modulate K different wavelength signal lights.

[0087] Taking the case where each grating has the same number of periods as an example, the electro-optic tunable device 700 provided in this application will be described. Assume that each grating includes m periods. These m periods can be different or the same, but all periods within each grating must be pairwise distinct. That is, when the m periods of each grating are different, in device 700, the M gratings include M*m periods, and at least one of these M*m periods can be used to select one of N wavelength signal lights. When each grating contains the same number of m periods, then in device 700, the M gratings include M periods, and at least one of these M periods can be used to select one of N wavelength signal lights.

[0088] It should be noted that the M gratings can be completely connected, that is, the M gratings can be equivalent to... Figure 6 The image shows a grating with a changing period. Alternatively, there may be intervals between the M gratings, for example... Figure 7 As shown, there is an interval between the m periods of the first grating and the m periods of the second grating.

[0089] It should be noted that one way to form the structure of the grating 702 is to periodically change the size of the waveguide along the direction of waveguide propagation. For example, the width of the waveguide can be changed, or other methods can be used. Please refer to the above description of the formation of the grating 602, which will not be repeated here.

[0090] K electrode pairs 703 are arranged sequentially along the transmission direction of waveguide 701, with each pair symmetrically positioned on the outer sides of the two sidewalls of waveguide 701. Each electrode pair is responsible for influencing the waveguide between them. For example, applying a voltage to the electrode pair controls the electric field of the waveguide between them, thereby changing the effective refractive index of that segment of the waveguide and thus affecting the characteristics of the output optical signal. The electrode material can be metal or transparent conductive oxide, etc.

[0091] It should be noted that the center position of each pair of electrodes should be located at the center position corresponding to the period of the grating to ensure the modulation effect of the electrode pair.

[0092] It should be understood that when modulating a signal light of a specific wavelength out of N wavelengths, a voltage can be applied to the electrode pair corresponding to that wavelength, while no voltage is applied to the other electrode pairs. This changes the refractive index of that waveguide segment, thereby shifting the position of the resonant wavelength in the output wavelength diagram. Conversely, if modulation of K wavelengths is required, different voltages can be applied simultaneously to multiple electrode pairs corresponding to those K wavelengths, thus achieving the goal of simultaneously modulating multiple wavelengths of signal light.

[0093] Based on the scheme of this application, a grating structure with varying period can independently adjust multiple wavelengths of input signal light, and high adjustment efficiency is achieved by utilizing the resonance effect of light.

[0094] Figure 8 This is a schematic diagram of an electro-optically adjustable device 800 according to an embodiment of this application. Figure 8 As shown, the electro-optically adjustable device 800 includes:

[0095] The waveguide 801, two gratings 802, and N electrode pairs 803 are provided. The two gratings 802 include a first grating and a second grating, and the K electrode pairs include a first electrode pair, a second electrode pair, up to the Kth electrode pair. N and K are both integers greater than 1.

[0096] Specifically, waveguide 801 is used to transmit input signal light of N wavelengths. Waveguide 801 extends along the X-direction, allowing the signal light to propagate along this direction within it. The waveguide can be a belt waveguide or a ridge waveguide structure. The material comprising the waveguide can be an electro-optic or thermo-optic tunable material, allowing the effective refractive index of the waveguide mode to vary with changes in the electric field, carrier concentration, or temperature of the waveguide region. The material of waveguide 801 may include lithium niobate, silicon, silicon nitride, barium titanate, or electro-optic polymers, etc.

[0097] A grating 802 is provided, wherein a first grating and a second grating can be placed near the two outer walls of the waveguide 801, located on both lateral sides of the waveguide 801. For example, the distance between the first grating and the second grating and the waveguide can satisfy a preset distance, which can be on the order of wavelength. Both the first grating and the second grating have varying periods in the transmission direction of the waveguide 801, and the period of the second grating at the same position along the extension direction of the waveguide 801 has a period difference from the period of the first grating.

[0098] It should be noted that all the periods included in the first grating are different from each other, and all the periods included in the second grating are also different from each other. However, there may be the same period between the periods included in the first grating and the second grating, but the same period is not located at the same position on the waveguide 801, that is, the periods of the two gratings at the same position on the waveguide are different.

[0099] In one feasible manner, the period difference between the period of the second grating and the period of the first grating at the same location along the extension direction of waveguide 801 is different.

[0100] In another possible implementation, the periods of the first and second gratings can vary uniformly, that is, the periods of the first and second gratings gradually increase or decrease simultaneously along the direction of waveguide propagation. For example... Figure 9 As shown, the period Λ1 of the first grating and the period Λ2 of the second grating gradually increase along the transmission direction of the waveguide 801, and the period difference ΔΛ between the period of the second grating and the period of the first grating at the same position along the extension direction of the waveguide 801 remains constant.

[0101] It should be understood that the first and second gratings can also be etched on the two outer walls of waveguide 801 respectively, in which case the width of the waveguide along the X direction changes periodically.

[0102] Furthermore, the method of forming the grating 802 can be referred to the method of forming the grating 602 described above, and will not be repeated here.

[0103] K electrode pairs 803 are arranged on both sides of the waveguide 801 laterally and outside the grating. Each electrode pair affects a section of the waveguide between the two electrodes, for example, by applying an electric field, injecting charge carriers, or heating the section of the waveguide, thereby changing the effective refractive index of the section of the waveguide and thus affecting the characteristics of the output light. The material of the K electrode pairs 803 can be metal or transparent conductive oxide, etc.

[0104] It should be noted that the K electrode pairs may share electrodes at one end. For example, multiple different signal electrodes may be used on one side of waveguide 801 to load different electrical signals, while a common ground electrode may be used on the other side.

[0105] Specifically, in combination Figure 10 and Figure 11 The modulation results shown illustrate the multi-wavelength modulation apparatus 800 provided in this application. Figure 10 and Figure 11 In the specific implementation shown, four signal lights with wavelengths λ1, λ2, λ3, and λ4 are input to the input terminal of waveguide 801. When no voltage is applied to the four electrode pairs of the device 800, the spectrum output by the device can be as follows: Figure 10 (a) shows the spectrum without voltage. When a voltage is applied to the electrode pair that adjusts λ2, the refractive index of the waveguide between the electrode pairs changes, causing the optical signal with wavelength λ2 to be modulated by the electrode signal and shift. Meanwhile, for the optical signals of the other three wavelengths, since they are not modulated by the electrical signal, the output spectrum does not change.

[0106] In comparison, Figure 10(b) shows the modulation result of the modulator based on the resonant cavity structure. When the refractive index of the waveguide is changed by the electrodes, multiple resonant wavelengths move together, and the effect of independent modulation of multiple wavelengths cannot be achieved.

[0107] When four input wavelengths are modulated simultaneously, for example Figure 11 As shown, different electrical signals can be applied to the four electrodes, so that the signal light of the four wavelengths is modulated by different signals, and the modulated multi-wavelength signal is output from the waveguide output port.

[0108] Therefore, the electro-optically tunable device provided in this application can achieve independent modulation of signals of different wavelengths by means of the influence of electrode pairs in different regions on the waveguide.

[0109] Figure 12 Simulation verification of the electro-optic tunable function of the device structure according to the embodiments of this application is provided. The simulation is based on the transfer-matrix method (TMM). In the simulation, the waveguide material is set as lithium niobate with an effective refractive index of 2. The initial periods of the two gratings near the waveguide input are set to 379 nm and 381 nm, respectively, and then the grating periods gradually increase along the waveguide propagation direction. Figure 12 The figures show the transmission and reflection spectra for different device lengths. Figure 12 (a) to Figure 12 (c) The length of the device gradually increases, from Figure 12 As can be seen, the number of resonant wavelengths gradually increases from 1 to 20 as the device length increases.

[0110] Figure 13 The following is for Figure 12 (c) shows the transmission spectrum change caused by applying an electric field to a section of the waveguide in the device. It is evident that the resonant wavelength λ6 undergoes a redshift due to the electric field at that location, while the other resonant wavelengths do not show significant changes. This verifies that the device can achieve independent wavelength adjustment.

[0111] It should be noted that in the electro-optically tunable device provided in this application embodiment, when the waveguide material is a semiconductor material, such as silicon, P-type and N-type doping can be performed on both sides of the waveguide respectively, forming a PN junction or a PIN junction at the waveguide, such as... Figure 14As shown, the concentration of charge carriers in the waveguide region can be controlled by electrodes on both sides of the waveguide, and the effective refractive index of the waveguide can be changed by utilizing the dispersion effect of charge carriers, thereby achieving modulation of the optical signal. This doped waveguide can be realized using silicon photonics fabrication processes compatible with complementary metal-oxide-semiconductor (CMOS) technology.

[0112] It should be understood that the waveguides in the electro-optic tunable devices 600, 700, and 800 provided in the embodiments of this application can all be doped waveguide structures.

[0113] Figure 17 Another waveguide structure that can be used in the embodiments of this application is shown. This structure forms an S-shaped structure by bending multiple segments of the waveguide in a U-shape. The S-shaped structure can shorten the length of the device and save space.

[0114] Regarding the above Figure 6 , Figure 7 , Figure 8 , Figure 14 , Figure 15 , Figure 16 as well as Figure 17 In the embodiments described, it should be noted that:

[0115] The above Figure 6 , Figure 7 , Figure 8 , Figure 14 , Figure 15 , Figure 16 as well as Figure 17 The embodiments can be implemented independently or in combination, for example... Figure 6 The illustrated embodiments and Figure 14 In combination, waveguide 601 can be used Figure 14 The doped waveguide material shown. Or Figure 6 The illustrated embodiments and Figure 17 In combination, waveguide 601 can be used Figure 17 The S-shaped waveguide structure shown is an example.

[0116] According to the apparatus provided in the embodiments of this application, this application also provides a communication system, which includes a transmitter, the transmitter comprising... Figures 6 to 8 The apparatus of any one of the embodiments shown.

[0117] It should be understood that in the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., high-density digital video discs (DVDs)), or semiconductor media (e.g., solid-state drives (SSDs)).

[0118] The terms “component,” “module,” “system,” etc., used in this specification are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, and / or a computer. As illustrated, applications running on computing devices and computing devices can both be components. One or more components may reside in a process and / or an execution thread, and components may be located on a single computer and / or distributed among two or more computers. Furthermore, these components can be executed from various computer-readable media on which various data structures are stored. Components can communicate, for example, via local and / or remote processes based on signals having one or more data packets (e.g., data from two components interacting with another component between a local system, a distributed system, and / or a network, such as the Internet interacting with other systems via signals).

[0119] Those skilled in the art will recognize that the various illustrative logical blocks and steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0120] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0121] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0122] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0123] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0124] In the above embodiments, the functions of each functional unit can be implemented entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions (programs). When the computer program instructions (programs) are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state disks, SSDs), etc.

[0125] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0126] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An electro-optically adjustable device, characterized in that, include: Waveguide, first grating, electrode pair The waveguide is used to transmit signal light of N wavelengths; The first grating includes M different periods for selecting some or all of the signal light from the N wavelengths of signal light; The electrode pair is used to modulate signal light of M wavelengths. Where M and N are integers greater than 1; The device further includes: a second grating, The second grating includes M different periods, used in conjunction with the first grating to select the M wavelengths of signal light. The second grating and the first grating are located on different sides of the waveguide, or the second grating and the first grating are both located above the waveguide. Wherein, the period of the second grating at the same position along the extension direction of the waveguide has a period difference from the period of the first grating.

2. The apparatus according to claim 1, characterized in that, The first grating is located on or above the sidewall of the waveguide, and the distance between the first grating and the waveguide is greater than or equal to 0.

3. The apparatus according to claim 1 or 2, characterized in that, The period difference is a constant at all locations along the extension direction of the waveguide.

4. The apparatus according to claim 1, characterized in that, The number of electrode pairs is K, and the K electrode pairs share the same electrode in each electrode pair.

5. The apparatus according to claim 1, characterized in that, The waveguide is made of silicon, a semiconductor material, and the regions of the waveguide near the electrode pair are doped with P-type and N-type doping, respectively.

6. The apparatus according to claim 1, characterized in that, The waveguide material includes materials with linear electro-optic effects.

7. The apparatus according to claim 1, characterized in that, The waveguide has an S-shaped structure.

8. A communication system, characterized in that, include: A transmitter comprising the means of any one of claims 1 to 7, and outputting a first optical signal; A transmission medium for transmitting the first optical signal output by the transmitter; A receiver is used to convert the first optical signal into a first electrical signal.

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