A mach-zehnder interferometer integrated with an array of tunable microring resonators

Abstract

The application discloses a Mach-Zehnder interferometer integrated with an adjustable microring resonator filter array and relates to the technical field of silicon-based photonic integrated devices, and comprises a first filter module, which is an eight-channel Mach-Zehnder interferometer; the first filter module is used for filtering and dividing an optical signal and outputs optical signals with different center wavelengths to a second filter module respectively; the second filter module comprises eight channels, each of which is provided with two cascaded microring resonator filters; the eight channels of the second filter module correspond to the eight channels of the first filter module one by one, and the second filter module is used for twice filtering the optical signals with different center wavelengths. Thus, the crosstalk level can be reduced, the second-order microring resonator filter can effectively suppress sidelobes and noise floors, and the filtered waveform still maintains a large channel bandwidth.

Description

Technical Field

[0001] This utility model relates to the field of silicon-based photonic integrated device technology, and more specifically to a Mach-Zehnder interferometer with an integrated tunable microring resonant filter array. Background Technology

[0002] As a key functional component in wavelength division multiplexing transceivers, high-performance optical filters have been continuously developed. Among them, silicon-based Mach-Zehnder interferometers (MZIs) are widely used due to their ultra-low insertion loss and compatibility with mature CMOS processes.

[0003] However, in existing silicon-based MZI topologies that reuse eight or more wavelengths, phase errors are easily accumulated due to process variations, leading to a sharp deterioration in device crosstalk and making calibration extremely difficult, severely limiting the performance of wavelength division multiplexing (WDM) systems. To reduce crosstalk, the industry has proposed fabricating MZI on silicon nitride platforms, but the lower refractive index difference leads to increased bending radius and chip area.

[0004] Therefore, there is an urgent need to provide an MZI solution that is compatible with standard CMOS processes and can significantly reduce inter-channel crosstalk without significantly increasing chip area and process complexity. Utility Model Content

[0005] The purpose of this invention is to provide a Mach-Zehnder interferometer with an integrated tunable microring resonant filter array. By changing the resonant wavelength, light from different channels can be filtered, thereby reducing the crosstalk level of the Mach-Zehnder interferometer with the integrated tunable microring resonant filter array. It is equipped with two cascaded microring resonant filters to generate the corresponding filtering response. It has the advantages of high out-of-band suppression, wide 3 dB bandwidth, flat passband, low signal distortion, and low temperature sensitivity. It can effectively suppress sidelobes and noise floor, and the filtered waveform still maintains a large channel bandwidth.

[0006] To achieve the above objectives, this utility model provides a Mach-Zehnder interferometer with an integrated tunable micro-ring resonant filter array, comprising: The first filtering module is an eight-channel Mach-Zehnder interferometer. The first filtering module is used to filter and divide the optical signal, and output optical signals with different center wavelengths to the second filtering module respectively; The second filtering module includes eight channels, each of which is equipped with two cascaded micro-ring resonant filters. The eight channels of the second filtering module correspond one-to-one with the eight channels of the first filtering module. The second filtering module is used to perform secondary filtering on the optical signals with different center wavelengths.

[0007] In another embodiment, both the Mach-Zehnder interferometer and the microring resonant filter are fabricated on a 220nm thick top silicon SOI wafer.

[0008] In another embodiment, a micro-thin film heater is integrated above the micro-ring resonant filter; The micro-thin film heater is used to fine-tune the resonant wavelength through the thermo-optic effect.

[0009] In another embodiment, the radius of the microring in the microring resonant filter is adjustable; The radius of the microring is used to control the resonant wavelength of each channel.

[0010] In another embodiment, the micro-film heater is a TiN micro-film heater; the micro-film heater is used to fine-tune the micro-ring refractive index of the micro-ring resonant filter through thermo-optic effect, thereby adjusting the resonant wavelength of each channel.

[0011] In another embodiment, the Mach-Zehnder interferometer with integrated tunable microring resonant filter array further includes: an input channel; The input channel is used to input optical signals to the first filtering module.

[0012] In another embodiment, the second filtering module further includes an output unit; The output unit includes eight output channels, which correspond one-to-one with the eight channels of the second filtering module. The output channels are used to output the optical signal after secondary filtering.

[0013] The beneficial effects of this invention are as follows: The Mach-Zehnder interferometer with integrated tunable microring resonant filter array in this invention includes: a first filtering module, which is an eight-channel Mach-Zehnder interferometer; the first filtering module is used to filter and divide optical signals, and output optical signals with different center wavelengths to a second filtering module; the second filtering module includes eight channels, each channel having two cascaded microring resonant filters; the eight channels of the second filtering module correspond one-to-one with the eight channels of the first filtering module, and the second filtering module is used to perform secondary filtering on the optical signals with different center wavelengths. By changing the resonant wavelength, the light from different channels can be filtered, thereby reducing the crosstalk level of the Mach-Zehnder interferometer with integrated tunable microring resonant filter array. Furthermore, the two cascaded microring resonant filters used to generate corresponding filtering responses have advantages such as high out-of-band suppression, wide 3 dB bandwidth, flat passband, low signal distortion, and low temperature sensitivity. It can effectively suppress sidelobes and noise floor, and the filtered waveform still maintains a large channel bandwidth.

[0014] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0015] Figure 1 This is a structural block diagram of a Mach-Zehnder interferometer with an integrated tunable microring resonant filter array, as shown in one embodiment of this application. Figure 2 This is a schematic diagram of a refined Mach-Zehnder interferometer with an integrated tunable microring resonant filter array, as shown in one embodiment of this application. Detailed Implementation

[0016] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. It should be noted that references to "an embodiment," "embodiment," "example embodiment," etc., in this specification refer to the described embodiment including specific features, structures, or characteristics; however, not every embodiment must include these specific features, structures, or characteristics. Furthermore, such expressions do not refer to the same embodiment. Moreover, when describing specific features, structures, or characteristics in conjunction with embodiments, whether or not explicitly described, it is indicated that incorporating such features, structures, or characteristics into other embodiments is within the knowledge scope of those skilled in the art.

[0017] Furthermore, certain terms are used in the specification and subsequent claims to refer to specific components or parts. Those skilled in the art will understand that manufacturers may use different names or terms to refer to the same component or part. This specification and subsequent claims do not distinguish components or parts by differences in name, but rather by differences in function. The terms "comprising" and "including" used throughout the specification and subsequent claims are open-ended and should be interpreted as "including but not limited to." Additionally, the term "connection" here includes any direct and indirect electrical connection means. Indirect electrical connection means include connections made through other means.

[0018] Please see Figure 1 , Figure 1A structural block diagram of a Mach-Zehnder interferometer with an integrated tunable microring resonant filter array is provided. The Mach-Zehnder interferometer with the integrated tunable microring resonant filter array includes: The first filtering module is an eight-channel Mach-Zehnder interferometer. It filters and divides the optical signal, outputting optical signals of different center wavelengths to the second filtering module. The second filtering module includes eight channels, each equipped with two cascaded micro-ring resonant filters. The eight channels of the second filtering module correspond one-to-one with the eight channels of the first filtering module. The second filtering module performs secondary filtering on the optical signals of different center wavelengths.

[0019] Optionally, both the Mach-Zehnder interferometer and the microring resonant filter are fabricated on a 220 nm thick top silicon SOI wafer to ensure compatibility with standard CMOS processes.

[0020] Optionally, the microring radius of the microring resonant filter is adjustable; the microring radius is used to control the resonant wavelength of each channel.

[0021] Optionally, a micro-thin-film heater is integrated above the micro-ring resonant filter; the micro-thin-film heater is a metal thin-film heater. In this embodiment, TiN is selected as the metal thin film to form a TiN micro-thin-film heater, which is used to adjust the refractive index of the micro-ring through thermo-optical effects to further fine-tune the resonant wavelength.

[0022] Optionally, the Mach-Zehnder interferometer with integrated tunable microring resonant filter array further includes: an input channel; the input channel is used to input an optical signal to the first filtering module.

[0023] Optionally, the second filtering module further includes an output unit; the output unit includes eight output channels, each corresponding to one of the eight channels of the second filtering module, and the output channels are used to output the optical signal after secondary filtering.

[0024] For example, such as Figure 2 As shown, Figure 2This is a schematic diagram of a refined integrated tunable microring resonant filter array Mach-Zehnder interferometer. When filtering an optical signal is required, the optical signal enters the first filtering module through the input channel. The Mach-Zehnder interferometer in the first filtering module performs primary filtering and wavelength division processing on the optical signal, obtaining eight optical signals with different center wavelengths. The optical signals with different center wavelengths are then output to the eight channels of the second filtering module, where they undergo secondary filtering by two cascaded microring resonant filters to suppress sidelobes and noise floor. The filtered waveform still maintains a large channel bandwidth. Finally, the signal is output through the eight output channels of the output unit. It should be noted that before the secondary filtering by the two cascaded microring resonant filters, the resonant wavelength needs to be adjusted by adjusting the refractive index of the microrings in the microring resonant filters to filter light of different wavelengths.

[0025] Furthermore, in this embodiment, a metal micro-thin film heater is integrated above the micro-ring resonant filter. The metal micro-thin film heater can adjust the refractive index of the micro-ring through the thermo-optic effect to further fine-tune the resonant wavelength.

[0026] The Mach-Zehnder interferometer with integrated tunable microring resonant filter array in the above embodiment includes: a first filtering module, which is an eight-channel Mach-Zehnder interferometer; the first filtering module is used to filter and divide the optical signal, and output optical signals with different center wavelengths to a second filtering module; the second filtering module includes eight channels, each channel having two cascaded microring resonant filters; the eight channels of the second filtering module correspond one-to-one with the eight channels of the first filtering module, and the second filtering module is used to perform secondary filtering on the optical signals with different center wavelengths. In this embodiment, two cascaded microring resonant filters are used to generate corresponding filtering responses, which have advantages such as high out-of-band rejection, wide 3 dB bandwidth, flat passband, low signal distortion, and low temperature sensitivity.

[0027] This application integrates a Mach-Zehnder interferometer with an tunable microring resonant filter array, which can filter optical signals twice, solving the device crosstalk problem caused by single filtering in the Mach-Zehnder interferometer. Furthermore, by adjusting the microring radius of the microring resonant filter and adjusting the refractive index of the microring through a micro-thin film heater, the resonant wavelength of each channel can be precisely adjusted and controlled to accurately filter the light from different channels. While reducing the crosstalk level of the Mach-Zehnder interferometer, it further effectively suppresses sidelobes and noise floor, and the filtered waveform still maintains a large channel bandwidth.

[0028] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0029] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A Mach-Zehnder interferometer with an integrated tunable micro-ring resonant filter array, characterized in that, The Mach-Zehnder interferometer with integrated tunable micro-ring resonant filter array includes: The first filtering module is an eight-channel Mach-Zehnder interferometer. The first filtering module is used to filter and divide the optical signal, and output optical signals with different center wavelengths to the second filtering module respectively; The second filtering module includes eight channels, each of which is equipped with two cascaded micro-ring resonant filters. The eight channels of the second filtering module correspond one-to-one with the eight channels of the first filtering module. The second filtering module is used to perform secondary filtering on the optical signals with different center wavelengths.

2. The Mach-Zehnder interferometer with an integrated tunable micro-ring resonant filter array as described in claim 1, characterized in that, Both the Mach-Zehnder interferometer and the microring resonant filter are fabricated on SOI wafers with a 220 nm thick top silicon layer.

3. The Mach-Zehnder interferometer with an integrated tunable micro-ring resonant filter array as described in claim 2, characterized in that, A micro-thin film heater is integrated above the micro-ring resonant filter; The micro-thin film heater is used to fine-tune the resonant wavelength through the thermo-optic effect.

4. The Mach-Zehnder interferometer with an integrated tunable micro-ring resonant filter array as described in claim 3, characterized in that, The radius of the microring in the microring resonant filter is adjustable; The radius of the microring is used to control the resonant wavelength of each channel.

5. The Mach-Zehnder interferometer with an integrated tunable micro-ring resonant filter array as described in claim 3, characterized in that, The micro-thin film heater is a TiN micro-thin film heater; the micro-thin film heater is used to fine-tune the refractive index of the micro-ring resonant filter through thermo-optic effect, thereby adjusting the resonant wavelength of each channel.

6. The Mach-Zehnder interferometer with an integrated tunable micro-ring resonant filter array as described in claim 1, characterized in that, The Mach-Zehnder interferometer with integrated tunable micro-ring resonant filter array further includes: an input channel; The input channel is used to input optical signals to the first filtering module.

7. The Mach-Zehnder interferometer with an integrated tunable micro-ring resonant filter array as described in claim 1, characterized in that, The second filtering module also includes an output unit; The output unit includes eight output channels, which correspond one-to-one with the eight channels of the second filtering module. The output channels are used to output the optical signal after secondary filtering.

Images