A wavelength selective switch device based on a micro-ring resonator array

Abstract

The application discloses a wavelength selective switch device based on a micro-ring resonator array. The application comprises an upper cladding layer, a lower cladding layer, a bus input / output waveguide and a plurality of wavelength selectors, the bus input / output waveguide and the plurality of wavelength selectors are arranged between the upper cladding layer and the lower cladding layer, and the plurality of wavelength selectors are arranged along the transmission direction of the bus input / output waveguide. Multi-channel wavelength signals are input from the bus waveguide, output from the bus waveguide or the uploading and downloading waveguide after simultaneous regulation and control of the plurality of micro-ring resonator units, and the selective transmission function of the multi-channel optical signals in different port directions is realized. The application has the advantages of simple and compact structure, convenient design and high stability, realizes the simultaneous and selective transmission of the multi-channel wavelength signals in different directions by using the inherent resonance characteristics of the micro-ring resonator, has low energy consumption and additional loss, and is suitable for a multi-channel wavelength division multiplexing system, an optical computing and a neural network field.

Description

Technical Field

[0001] This invention relates to a planar optical waveguide integrated device, and more particularly to a wavelength selective switching device based on a microring resonator array. Background Technology

[0002] Today, the ever-increasing demand for data transmission capacity places higher demands on the development of optical communication systems, especially optical interconnects in optical communication network nodes. In optical network nodes, reconfigurable optical add-drop multiplexers (ROADMs) are a key component for flexible allocation of wavelength channels in wavelength division multiplexing (WDM) networks. As an important component of ROADM systems, 1×M wavelength selection switches (WSS) with one input port and M output ports are widely used to select specific wavelength channels to any port in the WDM system with different directions; M×M wavelength selection switches with M input ports and M output ports are a key technology for reducing the system complexity of next-generation high-performance multi-channel ROADMs. Furthermore, with the increasing demand for computing performance in data centers in the Internet era, the scale of data center interconnects (DCIs) is growing exponentially, posing challenges to further improving the scalability and energy efficiency of optical interconnect networks. This also necessitates the application of high-performance 1×M or M×M wavelength selection switches.

[0003] Several technologies have been developed to implement wavelength selective switches. For example, free-space optical wavelength selective switches based on microelectromechanical systems (MEMS) or liquid crystal on silicon (LCOS) have been well-developed and applied in practical applications. However, the optical microlenses and switches in this approach require precise assembly, making the system very expensive and the device size very large. In contrast, the development of wavelength selective switches using silicon-based photonics technology shows great promise due to the compact footprint and high productivity of complementary metal-oxide-semiconductor (CMOS) processes. Silicon-based photonics offers advantages such as high integration, low power consumption, high bandwidth density, and semiconductor process technology compatibility. Wavelength selective switch devices based on this technology can be small in size, low in cost, and have high response time, making them suitable for integration with other optical devices and a potential solution for future large-scale all-optical signal processing.

[0004] Over the past few years, various on-chip wavelength selective switches have been realized using integrated MEMS structures, arrayed waveguide gratings (AWGs), Mach-Zehnder interferometers (MZIs), waveguide gratings, and microring resonators (MRRs). Using MEMS structures can effectively reduce channel crosstalk and achieve high switching extinction ratios (ERs), but the manufacturing complexity of large-scale fabrication remains challenging. Considering applications in WDM systems with multiple channels, a conventional waveguide-type 1×M WSS uses an AWG as a demultiplexer, M AWGs as multiplexers, and a 1×M MZI switch for wavelength routing per channel. Besides the excessive losses caused by the AWGs, this configuration inevitably introduces waveguide crossovers with excessive losses and additional crosstalk into the routing path. Furthermore, for MZI switches, the power consumption per wavelength channel is typically around tens of milliwatts, while a 1×M wavelength selective switch can be several millimeters long.

[0005] Compared to AWG and MZI types, wavelength selective switches based on microring resonators offer advantages such as smaller footprint, greater scalability, and lower power consumption. In particular, their wavelength selectivity, resulting from resonance, makes them more suitable for use in WDM systems. Furthermore, specific design features can be incorporated into microring resonators to improve ER and crosstalk performance, such as elliptical microring resonators and high-level hierarchical microrings. On the other hand, multi-channel 1×M and M×M wavelength selective switches play a crucial role in constructing wavelength-insensitive, direction-insensitive, and non-blocking (CDC) ROADM nodes in mesh optical networks. Therefore, it remains essential to achieve improved overall performance through simple component design and to expand the number of wavelength channels and communication ports of 1×M and M×M wavelength selective switches to enable flexible routing / switching of wavelength channels in large-scale optical communication networks. Summary of the Invention

[0006] To address the problems existing in the background technology, the present invention aims to provide a wavelength selective switching device based on a microring resonator array. This device uses microring resonators to independently control the amplitude of the optical signal in each wavelength channel, tuning and controlling the resonant peak position of each microring resonator, thereby precisely controlling the transmission direction of the signal at a specific wavelength in the optical link. This device possesses excellent scalability and tunability, is suitable for reconfigurable multi-channel wavelength division multiplexing systems, and meets low power consumption requirements.

[0007] The technical solution adopted in this invention is:

[0008] The present invention includes an upper cladding, a lower cladding, a bus input / output waveguide, and multiple wavelength selectors. The bus input / output waveguide and multiple wavelength selectors are all disposed between the upper cladding and the lower cladding. The multiple wavelength selectors are all disposed on the side of the bus input / output waveguide. The multiple wavelength selectors are arranged sequentially at intervals along the transmission direction of the bus input / output waveguide.

[0009] Each wavelength selector consists of m microring resonator units disposed between the upper and lower cladding layers and a upload / download waveguide. The upload / download waveguide is spaced apart from the bus input / output waveguide. m microring resonator units are sequentially spaced apart along the transmission direction of the bus input / output waveguide between the upload / download waveguide and the bus input / output waveguide. Each of the m microring resonator units is laterally evanescently coupled to the bus input / output waveguide and the upload / download waveguide. One end of the upload / download waveguide serves as the port of the current wavelength selector.

[0010] Each of the microring resonator units includes at least one microring resonator. In the current microring resonator unit, all microring resonators are disposed between the upper cladding and the lower cladding. If there are multiple microring resonators, in the current microring resonator unit, all microring resonators are disposed between the uplink / downlink waveguide and the bus input / output waveguide. All microring resonators are arranged sequentially at intervals. The microring resonators closer to the bus input / output waveguide are arranged at intervals with the bus input / output waveguide and are laterally evanescently coupled with the bus input / output waveguide. The microring resonators closer to the uplink / downlink waveguide are arranged at intervals with the uplink / downlink waveguide and are laterally evanescently coupled with the uplink / downlink waveguide. Adjacent microring resonators are also arranged at intervals and are laterally evanescently coupled with the uplink / downlink waveguide.

[0011] The upper or lower cladding of the microring resonator is embedded with a tuning electrode. Adjusting the power of the tuning electrode changes the thermo-optical effect of the microring resonator's temperature, changes the effective refractive index of the mode of the microring resonator, and thus controls the position of the resonant peak of the microring resonator.

[0012] Alternatively, doped ions can be injected into the microring resonator to form a tuning electrode. Adjusting the voltage of the tuning electrode changes the electro-optic effect of the number of charge carriers in the microring resonator, alters the effective refractive index of the mode of the microring resonator, and controls the position of the resonance peak of the microring resonator.

[0013] The bus input / output waveguides, microring resonators, and upload / download waveguides are made of the same material.

[0014] The microring resonator is a circular ring waveguide with the same waveguide width, a circular ring waveguide with a gradually changing waveguide width, an elliptical ring waveguide with the same waveguide width, or an elliptical ring waveguide with a gradually changing waveguide width.

[0015] The waveguide at the coupling point between the bus input / output waveguide and the corresponding microring resonator is either a straight waveguide, a curved waveguide with the center on the same side as the center of the corresponding coupled microring resonator, or a curved waveguide with the center on a different side of the center of the corresponding coupled microring resonator.

[0016] The waveguide at the coupling point between the upload / download waveguide and the corresponding microring resonator is either a straight waveguide, a curved waveguide with the center of the corresponding coupled microring resonator on the same side, or a curved waveguide with the center of the corresponding coupled microring resonator on different sides.

[0017] The waveguide widths of the bus input / output waveguide, microring resonator, and upload / download waveguide are set according to requirements; the spacing between the bus input / output waveguide, upload / download waveguide, and microring resonator is set according to requirements.

[0018] The waveguide shape and bending radius of each microring resonator are set according to requirements, and the spacing between adjacent microring resonators is set according to requirements.

[0019] The beneficial effects of this invention are as follows:

[0020] This invention features a simple and compact structure, convenient design, and high stability. It utilizes the inherent resonant characteristics of a microring resonator to achieve simultaneous and selective transmission of multiple wavelength signals in different directions, resulting in low energy consumption and additional losses. It is suitable for multi-channel wavelength division multiplexing systems, optical computing, and neural network fields. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the cross-section at the location of the micro-ring resonator.

[0023] Figure 3 This is a schematic diagram of various specific forms of microring resonators.

[0024] Figure 4 This is a schematic diagram of the structure when the bus input / output waveguide, upload / download waveguide, and microring resonator are coupled as a straight waveguide.

[0025] Figure 5 This is a schematic diagram of the structure when the bus input / output waveguide, upload / download waveguide, and microring resonator are coupled to a curved waveguide with their centers on the same side.

[0026] Figure 6 This is a schematic diagram of the structure when the bus input / output waveguide, upload / download waveguide, and microring resonator are coupled to a curved waveguide on different sides of the circle.

[0027] Figure 7This is a schematic diagram of a microring resonator unit, which is a microring resonator that consists of multiple microring resonators cascaded longitudinally and includes a upload / download waveguide.

[0028] Figure 8 This is a schematic diagram illustrating the change in the amplitude of the output optical signal at a certain operating wavelength of the wavelength selective switching device in an embodiment of the present invention as a function of the power of the tuning electrode.

[0029] Figure 9 This is a schematic diagram illustrating the variation of the transmission intensity at the output end of the bus input / output waveguide with wavelength under different operating states of the wavelength selective switching device at the through end and download end in a 1×4 port configuration according to an embodiment of the present invention.

[0030] Figure 10 This is a schematic diagram illustrating the variation of the transmission intensity at the output end of the bus input / output waveguide with wavelength under different operating states of the wavelength selective switching device at the through end and download end in a 4×4 port configuration according to an embodiment of the present invention.

[0031] In the figure: 1. Bus input / output waveguide, 2. Micro-ring resonator unit, 3. Micro-ring resonator, 4. Upload / download waveguide, 5. Tuning electrode, 6. Upper cladding, 7. Lower cladding, 8. Straight waveguide coupling structure, 9. Co-directional curved waveguide coupling structure, 10. Reverse curved waveguide coupling structure. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] like Figure 1 As shown, the present invention includes an upper cladding layer 6, a lower cladding layer 7, a bus input / output waveguide 1, and multiple wavelength selectors. The bus input / output waveguide 1 and the multiple wavelength selectors are all disposed between the upper cladding layer 6 and the lower cladding layer 7, that is, the bus input / output waveguide 1 and the multiple wavelength selectors are covered by the upper cladding layer 6 and the lower cladding layer 7. The bus input / output waveguide 1 is used to transmit multiple optical wavelength signals. The multiple wavelength selectors are all disposed on the side of the bus input / output waveguide 1, and the multiple wavelength selectors are arranged sequentially at intervals along the transmission direction of the bus input / output waveguide 1. All wavelength selectors are laterally evanescently coupled to the bus input / output waveguide 1. The transmission direction of the bus input / output waveguide 1 is determined by the axes at its two ends. Different wavelength selectors are located on the same side or different sides of the bus input / output waveguide 1, and no lateral evanescent wave coupling occurs between adjacent wavelength selectors. Multiple wavelength signals are input from the bus input / output waveguide 1 and output from the bus input / output waveguide 1 or the upload / download waveguide 4 after simultaneous modulation of multiple micro-ring resonator units, thus realizing the selective transmission of multiple optical signals in different port directions.

[0034] In this embodiment, m×n microring resonator units 2 are used, denoted sequentially as port 1-λ1, ..., port 1-λm, ..., port n-λ1, ..., port n-λm. Each microring resonator unit 2 regulates the optical power amplitude of the corresponding channel. The m×n microring resonator units 2 can achieve simultaneous independent regulation of the optical power amplitude of m channels at n ports.

[0035] Each wavelength selector consists of m microring resonator units 2 disposed between the upper cladding layer 6 and the lower cladding layer 7, and an upload / download waveguide 4. The upload / download waveguide 4 is spaced apart from the bus input / output waveguide 1. m microring resonator units 2 are sequentially spaced apart along the transmission direction of the bus input / output waveguide 1 between the upload / download waveguide 4 and the bus input / output waveguide 1. No lateral evanescent wave coupling occurs between the m microring resonator units 2, but lateral evanescent wave coupling occurs between each of the m microring resonator units 2 and both the bus input / output waveguide 1 and the upload / download waveguide 4, thus enabling the microring resonators to... Within the micro-ring resonator 3, an optical field resonance is generated, resulting in a resonance peak at a specific location. By adjusting the position of the resonance peak generated by the micro-ring resonator 3, the corresponding wavelength signal is positioned at a specific resonance peak location, thereby controlling the transmission of that wavelength signal through the bus input / output waveguide 1 or a specific upload / download waveguide 4. Multiple wavelength signals are input from the same bus input / output waveguide 1. By simultaneously controlling multiple micro-ring resonator units 2, the output direction of each wavelength signal is determined to be either the same bus input / output waveguide 1 or a specific upload / download waveguide 4, thus achieving wavelength selection for multiple optical signals. One end of the upload / download waveguide 4 serves as the port of the current wavelength selector, and the port of the wavelength selector serves as the signal upload port or signal download port.

[0036] The input and output of multiple optical wavelength signals pass through the same bus input / output waveguide 1. Multiple optical wavelength signals are input from one side of the bus input / output waveguide 1 and output from the other side. Through the tuning effect of the micro-ring resonator 3 corresponding to a specific wavelength channel, a certain optical signal input from one side of the bus input / output waveguide 1 corresponding to a specific wavelength channel is coupled by the evanescent wave of the micro-ring resonator 3. The amplitude of the optical signal at that wavelength is tuned by the power of the resonant peak of the micro-ring resonator 3 at a specific position, so that the resonant peak is aligned with or offset from the position of the corresponding wavelength channel, thereby determining whether the output direction of each wavelength signal is the same bus input / output waveguide 1 or a certain upload / download waveguide 4, and realizing the wavelength selection function of multiple optical signals.

[0037] By applying power or voltage to the tuning electrode 5 to induce a thermo-optical or electro-optical effect, the effective refractive index of the mode of the micro-ring resonator 3 is changed, and the position of the resonant peak of the micro-ring resonator 3 is adjusted, thereby determining whether the output direction of each wavelength signal is the same bus input / output waveguide 1 or a certain upload / download waveguide 4.

[0038] In this way, one of the multiple optical wavelength signals input from one side of the bus input / output waveguide 1 is subjected to power tuning by the corresponding micro-ring resonator 3 when the resonant peak is at a specific position. After passing through the micro-ring resonator 3, the resonant peak at the specific position is aligned with or offset from the position of the corresponding optical signal wavelength, thereby determining whether the output direction of the wavelength signal is the same bus input / output waveguide 1 or a certain upload / download waveguide 4. Each of the multiple optical wavelength signals is subjected to power tuning by a corresponding micro-ring resonator 3, thereby determining whether the output direction of each wavelength signal is the same bus input / output waveguide 1 or a certain upload / download waveguide 4.

[0039] like Figure 7 As shown, each microring resonator unit 2 includes at least one microring resonator 3. The number of microring resonators 3 in the m microring resonator units 2 in each wavelength selector is the same or different. In the current microring resonator unit 2, all microring resonators 3 are disposed between the upper cladding 6 and the lower cladding 7. If there are multiple microring resonators 3, then in the current microring resonator unit 2, all microring resonators 3 are disposed between the upload / download waveguide 4 and the bus input / output waveguide 1. All microring resonators 3 are arranged sequentially at intervals. The microring resonators 3 closer to the bus input / output waveguide 1 are arranged at intervals and are laterally evanescently coupled to the bus input / output waveguide 1. The microring resonators 3 closer to the upload / download waveguide 4 are arranged at intervals and are laterally evanescently coupled to the upload / download waveguide 4. Adjacent microring resonators 3 are also arranged at intervals and are laterally evanescently coupled to each other.

[0040] A tuning electrode 5 is embedded in the upper cladding 6 or the lower cladding 7 outside the microring resonator 3. Adjusting the power of the tuning electrode 5 changes the thermo-optical effect of the temperature of the microring resonator 3, changes the effective refractive index of the mode of the microring resonator 3, and thus controls the position of the resonance peak of the microring resonator 3. In turn, controlling the position of the resonance peak of the microring resonator 3 controls the amplitude of the optical power output from the bus input / output waveguide 1 at a specific wavelength.

[0041] Alternatively, doped ions can be injected into the microring resonator 3 to form a tuning electrode 5. Adjusting the voltage of the tuning electrode 5 changes the electro-optic effect of the number of charge carriers in the microring resonator 3, changes the effective refractive index of the mode of the microring resonator 3, and controls the position of the resonance peak of the microring resonator 3, thereby controlling the optical power amplitude of the optical signal output from the bus input / output waveguide 1 at a specific wavelength.

[0042] The bus input / output waveguide 1, microring resonator 3, and upload / download waveguide 4 are made of the same material, specifically single-mode or multi-mode waveguides composed of silicon, doped silicon dioxide, silicon nitride, lithium niobate, etc. The upper cladding 6 and lower cladding 7 are both surrounding cladding media, specifically silicon dioxide.

[0043] The microring resonator 3 can be a circular ring waveguide with a uniform waveguide width, a circular ring waveguide with a gradually changing waveguide width, an elliptical ring waveguide with a uniform waveguide width, or an elliptical ring waveguide with a gradually changing waveguide width, as shown below. Figure 3 As shown in (a)-(d). The waveguide shape and bending radius of each microring resonator 3 are set according to requirements, and the spacing between adjacent microring resonators 3 is set according to requirements.

[0044] The waveguide at the coupling point between the bus input / output waveguide 1 and the corresponding micro-ring resonator 3 is a straight waveguide 8, such as... Figure 4 As shown, the curved waveguide 9, whose center is on the same side as the corresponding coupled microring resonator 3, is as follows: Figure 5 As shown, or the corresponding curved waveguide 10 with the center of the coupled microring resonator 3 on different sides, such as Figure 6 As shown.

[0045] Upload / download: The waveguide at the coupling point between waveguide 4 and the corresponding microring resonator 3 is a straight waveguide 8, such as... Figure 4 As shown, the curved waveguide 9, whose center is on the same side as the corresponding coupled microring resonator 3, is as follows: Figure 5 As shown, or the corresponding curved waveguide 10 with the center of the coupled microring resonator 3 on different sides, such as Figure 6 As shown. In the unidirectional curved waveguide coupling structure 9, the curved waveguide and the micro-ring resonator 3 form a concentric or non-concentric circular structure, and the coupling length of the coupling region is variable, that is, the surrounding angle is variable.

[0046] The waveguide widths of bus input / output waveguide 1, microring resonator 3, and upload / download waveguide 4 are set according to requirements; the spacing between bus input / output waveguide 1, upload / download waveguide 4, and microring resonator 3 is set according to requirements.

[0047] The working process and principle of this invention are as follows:

[0048] In wavelength selective switching devices, the amplitude of each optical signal in a multi-channel optical signal is controlled by a corresponding micro-ring resonator unit 2. The multi-channel optical signals are input from the input terminal of the bus input / output waveguide 1, undergo power tuning by each corresponding micro-ring resonator unit 2, and are then output from the output terminal of the bus input / output waveguide 1, achieving simultaneous amplitude equalization of the multi-channel optical signals. By applying power to the tuning electrode 5 to change the temperature of the micro-ring resonator 3 through a thermo-optic effect, or by applying voltage to the tuning electrode 5 to change the number of charge carriers in the waveguide of the micro-ring resonator 3 through an electro-optic effect, the effective refractive index of the mode of the micro-ring resonator 3 is changed, thus controlling the position of the resonance peak of the micro-ring resonator 3 and thereby controlling the optical power amplitude of the optical signal output from the bus input / output waveguide 1 at a specific wavelength.

[0049] The initial state of the wavelength selective switching device is when the power applied to the tuning electrodes 5 of all microring resonator units 2 applying the thermo-optic effect is 0, and the voltage applied to the tuning electrodes 5 of all microring resonator units 2 applying the electro-optic effect is 0. When power is applied to the tuning electrodes 5 of all microring resonator units 2 applying the thermo-optic effect, and the voltage applied to the tuning electrodes 5 of all microring resonator units 2 applying the electro-optic effect is an appropriate value, the optical wavelength signal of each channel and the resonance peak of the corresponding microring resonator 3 in the microring resonator unit 2 are all in a completely detuned state, that is, the resonance peak position is misaligned with the wavelength channel, and the misalignment distance is half a channel interval. Since the optical signal at each wavelength channel does not meet the phase matching condition of the lateral evanescent wave coupling between the microring resonator 3 and the bus input / output waveguide 1 and the upload / download waveguide 4 in the completely detuned state, the optical signal can pass through the microring resonator unit 2 without loss and be output from the output end of the bus input / output waveguide 1. The amplitude of the optical signal does not attenuate, which is the closed state of the wavelength channel.

[0050] When the state of the tuning electrode 5 is changed through thermo-optic or electro-optic effects, causing the resonant peak of the micro-ring resonator 3 in each micro-ring resonator unit 2 to move towards the corresponding wavelength channel, the optical signal at that wavelength channel gradually satisfies the phase matching condition of lateral evanescent wave coupling. The wavelength gradually moves to the position of the resonant peak of the micro-ring resonator 3 and gradually moves towards a position with a larger attenuation. Correspondingly, after the optical signal passes through the micro-ring resonator unit 2, the attenuation at the output of the bus input / output waveguide 1 gradually increases. When the shift of the resonant peak of the micro-ring resonator 3 reaches half a channel interval, the resonant peak of the micro-ring resonator 3 coincides with the position of the corresponding wavelength channel. The optical signal at the wavelength channel fully satisfies the phase matching condition of lateral evanescent wave coupling and is selected to be output from the download end of the upload / download waveguide 4. This makes the attenuation at the output of the bus input / output waveguide 1 reach its maximum, and the amplitude at the output end 4 of the upload / download waveguide 4 reaches its maximum, which is the open state of the wavelength channel. When multiple optical signals are simultaneously input to the wavelength selection switching device, by controlling the position of the resonant peak of the micro-ring resonator 3 in each micro-ring resonator unit 2 to make it coincide with or staggered by half a channel interval with the position of the corresponding wavelength channel, the function of selective transmission of multiple optical signals in different directions can be realized.

[0051] Specific embodiments of the present invention are as follows:

[0052] This example uses a silicon nanowire optical waveguide based on silicon-on-insulator (SOI) material. The core layer is silicon with a thickness of 220 nm and a refractive index of 3.4744, while the surrounding cladding is silicon dioxide with a refractive index of 1.444. The waveguide operates in the C-band communication range of 1530 nm to 1565 nm. By applying power to the tuning electrode 5 to change the temperature of the micro-ring resonator 3, the effective refractive index of the mode of the micro-ring resonator 3 is altered, thus controlling the position of the resonant peak and consequently regulating the optical power amplitude of the optical signal output from the bus input / output waveguide 1 at a specific wavelength.

[0053] Figure 2 A cross-sectional schematic diagram of the microring resonator 3 is provided. The tuning electrode 5, made of titanium / chromium, is placed in the upper cladding 6 above the microring resonator 3, covering only a portion of the microring resonator 3 to improve the precision of the shifting of the resonant peak of the microring resonator 3. By applying electrical power, Joule heating is generated in the tuning electrode 5 and conducted to the microring resonator 3 through the upper cladding, changing the temperature of the microring resonator 3. The effective refractive index of the mode of the microring resonator 3 is altered using the thermo-optic effect.

[0054] The microring resonator 3 is specifically an elliptical ring waveguide with a gradually changing waveguide width. The two minor axes of the ellipse of the microring resonator 3 form its coupling region with the bus input / output waveguide 1 and the upload / download waveguide 4. This region has the largest radius of curvature and the narrowest waveguide width, used to achieve high-efficiency, low-loss coupling. The two major axes of the ellipse of the microring resonator 3 are the uncoupled regions, with the smallest radius of curvature and the widest waveguide width. This is used to reduce the length of the microring to increase the free spectral range of the microring resonator 3, while simultaneously reducing transmission loss within the microring resonator 3.

[0055] The coupling structure between the microring resonator 3 and the bus input / output waveguide 1 and upload / download waveguide 4 can be a straight waveguide coupling structure 8, a curved waveguide coupling structure 9 with the same direction, or a curved waveguide coupling structure 10 with opposite directions. In this example, the straight waveguide coupling structure 8 is used.

[0056] In the device structure of the embodiment, the waveguide width of bus input / output waveguide 1 and upload / download waveguide 4 is W. bus =400nm. The microring resonator 3 is an elliptical ring waveguide with a gradually changing waveguide width, its major axis being L. a =4μm, the waveguide width is widest here, W a =650nm; its minor axis is L b =3.5μm, the waveguide width is narrowest here, which is W b =450nm, waveguide widths all satisfy single-mode transmission conditions. In the coupling structure of bus input / output waveguide 1, upload / download waveguide 4, and microring resonator 3, the waveguide spacing in the coupling region is W. gap =220nm. This wavelength selection switch contains a total of 4 wavelength channels, with a channel spacing of 400GHz between each wavelength channel. In order to keep the spacing between the resonant peaks of the micro-ring resonators 3 in each micro-ring resonator unit 2 consistent with this channel spacing, the major axis and minor axis of the micro-ring resonators 3 between adjacent wavelength channels are both set with a difference of 12.8nm, which is used to provide the spacing between the resonant peaks of adjacent micro-ring resonators 3.

[0057] Figure 8A schematic diagram illustrating the variation of the output optical signal amplitude at a specific operating wavelength of the wavelength selection switch in this embodiment with the power of the tuning electrode 5 is provided. The optical signal at this operating wavelength is input from the input terminal of the bus input / output waveguide 1. After power tuning by the corresponding micro-ring resonator unit 2, the amplitude of the optical signal changes. Depending on the tuning power, the optical signal power at the operating wavelength is output from the output terminal of the bus input / output waveguide 1, or from the output terminal of the upload / download waveguide. The leftmost end of the curve corresponds to the wavelength selection switch being in the closed state. At this time, the optical wavelength signal of this channel is completely detuned to the resonance peak of the micro-ring resonator 3 in the corresponding micro-ring resonator unit 2, i.e., the resonance peak position is misaligned with the wavelength channel, with a misalignment distance of half a channel interval. In this state, the optical signal can pass through the micro-ring resonator unit 2 with virtually no loss, with an additional loss of less than 0.5 dB and crosstalk of less than 20 dB, as shown by the star-shaped markings in the figure. As the power of the tuning electrode 5 gradually increases, the resonance peak of the micro-ring resonator 3 in the micro-ring resonator unit 2 gradually approaches the wavelength channel, corresponding to a gradual increase in the attenuation of the signal at the output of the bus input / output waveguide 1, and a decrease in the amplitude of the optical signal. When the power of the tuning electrode 5 increases to approximately 4mW, the resonance peak of the micro-ring resonator 3 in the micro-ring resonator unit 2 shifts by half a channel interval and coincides with the wavelength channel, corresponding to a maximum attenuation of approximately 16dB at the output of the bus input / output waveguide 1 at the wavelength channel, and a minimum decrease in the amplitude of the optical signal. Consequently, the amplitude of the optical signal at the download end is the maximum, with a loss of less than 1dB. As the power of the tuning electrode 5 continues to increase, the resonance peak of the micro-ring resonator 3 in the micro-ring resonator unit 2 gradually moves away from the wavelength channel, corresponding to a gradual decrease in the attenuation of the signal at the output of the bus input / output waveguide 1, and an increase in the amplitude of the optical signal. Figure 8 It can be seen that the power change applied to the tuning electrode 5 can cause a change in the amplitude of the optical signal in the corresponding wavelength channel.

[0058] Figure 9 A schematic diagram is given in the embodiment showing the change of transmission intensity at the output end of the bus input / output waveguide 1 with wavelength under different working states of a single upload / download port for the wavelength selection switch. Figure 9 (a) is the transmission spectrum when no power is applied to the tuning electrodes 5 of the four channels. Due to manufacturing errors, the spacing between the resonance peaks of the micro-ring resonators 3 in each micro-ring resonator unit 2 is uneven, which is the initial state. Figure 9 (b) is to adjust the tuning electrodes 5 of the four channels to make the wavelength selection switch completely closed. At this time, the optical wavelength signal of each channel and the resonance peak of the micro-ring resonator 3 in the corresponding micro-ring resonator unit 2 are completely detuned. That is, the position of the resonance peak and the wavelength channel are misaligned. The misalignment distance is half a channel interval. Each optical signal can pass through its corresponding micro-ring resonator unit 2 with basically no loss. Figure 9(c) is to adjust only the tuning electrode 5 of the first channel to redshift the optical signal of the corresponding channel by 200G on the basis of the complete closed state, so that the amplitude attenuation in the bus waveguide output reaches the maximum and the amplitude in the upload and download waveguide 4 output reaches the maximum, thus realizing the open state of the λ1 channel. Figure 9 (d) means that, on the basis of being completely closed, only the tuning electrodes 5 of the first and third channels are adjusted to maximize the attenuation of the optical signal at the output end of the bus waveguide and maximize the amplitude at the output end of the upload and download waveguide 4, thereby realizing the open state of the λ1 and λ3 channels. Figure 9 (e) is to adjust the tuning electrodes 5 of the 2nd and 4th channels only on the basis of the complete off state so that the amplitude attenuation of the optical signal of the corresponding channel in the bus waveguide output end reaches the maximum, and the amplitude in the upload and download waveguide 4 output end reaches the maximum, so as to realize the on state of the λ2 and λ4 channels. Figure 9 (f) represents adjusting only the tuning electrodes 5 of channels 1, 2, and 3 from the all-off state to maximize the attenuation of the optical signal amplitude at the bus waveguide output and the amplitude at the upload / download waveguide 4 output, thus enabling channels λ1, λ2, and λ3. Figure 9 As can be seen, the wavelength selection switch device in the embodiment can simultaneously control the amplitude and direction of multiple optical signals.

[0059] Figure 10 The embodiment demonstrates the operation of the wavelength selection switch in which optical signals from different channels are selectively transmitted to the upload / download waveguides 4 in different directions from multiple upload / download ports 4. Figure 10 (a) is based on the initial fully closed state, the resonance peaks of the micro-ring resonators 3 in the micro-ring resonator unit 2 of the first channel in port 1, the second channel in port 2, the third channel in port 3, and the fourth channel in port 4 are tuned to coincide, so that the amplitude of the optical signal of the first wavelength channel at the output end of the uplink / downlink waveguide 4 of port 1 reaches the maximum, the amplitude of the optical signal of the second wavelength channel at the output end of the uplink / downlink waveguide 4 of port 2 reaches the maximum, the amplitude of the optical signal of the third wavelength channel at the output end of the uplink / downlink waveguide 4 of port 3 reaches the maximum, and the amplitude of the optical signal of the fourth wavelength channel at the output end of the uplink / downlink waveguide 4 of port 4 reaches the maximum. Figure 10(b) involves tuning the resonance peaks of the micro-ring resonators 3 in the micro-ring resonator unit 2 of the fourth channel in port 1, the third channel in port 2, the second channel in port 3, and the first channel in port 4 to coincide, so that the amplitude of the optical signal of the first wavelength channel at the output of the uplink / downlink waveguide 4 at port 4 reaches its maximum, the amplitude of the optical signal of the second wavelength channel at the output of the uplink / downlink waveguide 4 at port 3 reaches its maximum, the amplitude of the optical signal of the third wavelength channel at the output of the uplink / downlink waveguide 4 at port 2 reaches its maximum, and the amplitude of the optical signal of the fourth wavelength channel at the output of the uplink / downlink waveguide 4 at port 1 reaches its maximum. Figure 10 As can be seen, in the embodiment, the resonant peak of the micro-ring resonator 3 in the multiple adjacent micro-ring resonator units 2 of the wavelength selective switch can be adjusted to coincide with the position of a certain wavelength channel, which is used to achieve the switching function of selective transmission of the wavelength channel, and the signal loss at the download end is less than 1dB.

[0060] Therefore, it can be seen that the present invention uses a micro-ring resonator as the basic structural unit of the wavelength selective switching device, which is simple and compact in structure, convenient in design, and highly stable. By adjusting the position of the resonant peak of the micro-ring resonator, the transmission direction of the optical signal at a specific wavelength can be achieved. Only a single bus waveguide is required to realize the simultaneous transmission of multiple ports and multiple wavelength signals, which has smaller device size, lower additional loss and energy consumption, and achieves outstanding technical effects.

[0061] The above embodiments are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A wavelength selective switching device based on a microring resonator array, characterized in that, It includes an upper cladding (6), a lower cladding (7), a bus input / output waveguide (1), and multiple wavelength selectors. The bus input / output waveguide (1) and multiple wavelength selectors are all located between the upper cladding (6) and the lower cladding (7). The multiple wavelength selectors are all located on the side of the bus input / output waveguide (1). The multiple wavelength selectors are arranged sequentially at intervals along the transmission direction of the bus input / output waveguide (1). Each wavelength selector consists of m micro-ring resonator units (2) disposed between the upper cladding (6) and the lower cladding (7) and an upload / download waveguide (4). The upload / download waveguide (4) is arranged at intervals with the bus input / output waveguide (1). The upload / download waveguide (4) and the bus input / output waveguide (1) are arranged at intervals along the transmission direction of the bus input / output waveguide (1). The m micro-ring resonator units (2) are all laterally evanescently coupled with the bus input / output waveguide (1) and the upload / download waveguide (4). One end of the upload / download waveguide (4) serves as the port of the current wavelength selector. Each of the microring resonator units (2) includes at least one microring resonator (3). In the current microring resonator unit (2), all microring resonators (3) are disposed between the upper cladding (6) and the lower cladding (7). If there are multiple microring resonators (3), in the current microring resonator unit (2), all microring resonators (3) are disposed between the uplink / downlink waveguide (4) and the bus input / output waveguide (1). All microring resonators (3) are arranged in sequence at intervals. The microring resonators (3) close to the bus input / output waveguide (1) are arranged at intervals with the bus input / output waveguide (1) and are coupled laterally to the bus input / output waveguide (1). The microring resonators (3) close to the uplink / downlink waveguide (4) are arranged at intervals with the uplink / downlink waveguide (4) and are coupled laterally to the uplink / downlink waveguide (4). Adjacent microring resonators (3) are also arranged at intervals and are coupled laterally to the bus input / output waveguide (1).

2. The wavelength selective switching device based on a microring resonator array according to claim 1, characterized in that, The upper cladding (6) or lower cladding (7) outside the microring resonator (3) is fitted with a tuning electrode (5). Adjusting the power of the tuning electrode (5) changes the thermo-optical effect of the temperature of the microring resonator (3), changes the effective refractive index of the mode of the microring resonator (3), and thus controls the position of the resonance peak of the microring resonator (3). Alternatively, after injecting doped ions into the microring resonator (3), a tuning electrode (5) can be formed. Adjusting the voltage of the tuning electrode (5) changes the electro-optic effect of the number of charge carriers in the microring resonator (3), changes the effective refractive index of the mode of the microring resonator (3), and controls the position of the resonance peak of the microring resonator (3).

3. The wavelength selective switching device based on a microring resonator array according to claim 1, characterized in that, The bus input / output waveguide (1), microring resonator (3), and upload / download waveguide (4) are made of the same material.

4. A wavelength selective switching device based on a microring resonator array according to claim 1, characterized in that, The microring resonator (3) is a circular ring waveguide with the same waveguide width, a circular ring waveguide with a gradually changing waveguide width, an elliptical ring waveguide with the same waveguide width, or an elliptical ring waveguide with a gradually changing waveguide width.

5. A wavelength selective switching device based on a microring resonator array according to claim 1, characterized in that, The waveguide at the coupling point between the bus input / output waveguide (1) and the corresponding micro-ring resonator (3) is a straight waveguide (8), a curved waveguide (9) with the center of the corresponding coupled micro-ring resonator (3) on the same side, or a curved waveguide (10) with the center of the corresponding coupled micro-ring resonator (3) on different sides.

6. A wavelength selective switching device based on a microring resonator array according to claim 1, characterized in that, The waveguide at the coupling point between the upload / download waveguide (4) and the corresponding micro-ring resonator (3) is a straight waveguide (8), a curved waveguide (9) with the center of the corresponding coupled micro-ring resonator (3) on the same side, or a curved waveguide (10) with the center of the corresponding coupled micro-ring resonator (3) on different sides.

7. A wavelength selective switching device based on a microring resonator array according to claim 1, characterized in that, The waveguide widths of the bus input / output waveguide (1), the microring resonator (3), and the upload / download waveguide (4) are set according to requirements; the spacing between the bus input / output waveguide (1), the upload / download waveguide (4), and the microring resonator (3) is set according to requirements.

8. A wavelength selective switching device based on a microring resonator array according to claim 1, characterized in that, The waveguide shape and bending radius of each microring resonator (3) are set according to requirements, and the spacing between adjacent microring resonators (3) is set according to requirements.

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