Wavelength division multiplexing system and wavelength division multiplexing transceiver system

Abstract

The invention discloses a wavelength division multiplexing system and a wavelength division multiplexing transceiving system, and the wavelength division multiplexing system comprises an input waveguide, a beam splitter connected with the input waveguide, a delay line waveguide connected with at least one output end of the beam splitter, and an output waveguide connected with the delay line waveguide, the waveguide material of the input waveguide is top silicon in the silicon insulator substrate; the delay line waveguide is a silicon waveguide, the delay line waveguide comprises a doped region, and the refractive index of the doped region is different from that of other regions except the doped region in the delay line waveguide. According to the invention, the problem of wavelength shift caused by processing reasons of a wavelength division multiplexing system in the prior art is solved.

Description

Technical Field

[0001] This application relates to the field of communication technologies, and in particular, to a wavelength division multiplexing system and a wavelength division multiplexing transceiver system. Background Art

[0002] In high-speed and high-capacity optical communications, wavelength division multiplexing (WDM) is an effective means to improve the capacity of optical communications. Combining with a photonic integrated chip can effectively reduce the size of devices and improve the integration of the system. The key devices are wavelength division multiplexing devices and wavelength demultiplexing devices.

[0003] However, since the optical waveguide devices in a silicon-based wavelength division multiplexer are affected by variations in width, inclination, silicon wafer waveguide thickness, and temperature caused by the processing technology, the central wavelength of the silicon-based wavelength division multiplexing device is shifted. In addition, for high-channel number architectures, additional delay lines are required for step-by-step demultiplexing, resulting in a further increase in the total signal propagation length and the accumulation of phase errors. Therefore, these devices need to adjust the resonant wavelength after manufacturing. In practical applications, a thermo-optic phase shifter (or heater) is usually used to correct the phase errors caused by manufacturing variations, but at the cost of a complex control circuit and a time-consuming correction algorithm, and it will increase the power consumption of the system.

[0004] It can be seen that the wavelength division multiplexing system in the related technology has the problem of wavelength shift caused by processing reasons. Therefore, it is necessary to find a non-volatile resonant wavelength regulation method that can correct the manufacturing errors by permanently changing the refractive index of the waveguide or cladding material after the device is manufactured. Summary of the Invention

[0005] Embodiments of this application provide a wavelength division multiplexing system and a wavelength division multiplexing transceiver system to at least solve the problem of wavelength shift caused by processing reasons in the wavelength division multiplexing system in the related technology.

[0006] According to one aspect of the embodiments of this application, a wavelength division multiplexing system is provided, including: an input waveguide, a beam splitter connected to the input waveguide, a delay line waveguide connected to at least one output end of the beam splitter, and an output waveguide connected to the delay line waveguide, where the waveguide material of the input waveguide is the top layer silicon in a silicon-on-insulator substrate; the delay line waveguide is a silicon waveguide, and the delay line waveguide includes a doped region, and the refractive index of the doped region is different from the refractive index of other regions in the delay line waveguide except the doped region.

[0007] According to another aspect of the embodiments of the present application, there is also provided a wavelength division multiplexing transceiver system, including: at least one wavelength division multiplexing component disposed on a silicon-on-insulator wafer, and the wavelength division multiplexing component includes the wavelength division multiplexing system described in any one of the above.

[0008] According to still another aspect of the embodiments of the present application, there is also provided a method for manufacturing a wavelength division multiplexing component, including: providing a silicon-on-insulator substrate; forming an input waveguide, a beam splitter connected to the input waveguide, a delay line waveguide connected to at least one output end of the beam splitter, and an output waveguide connected to the delay line waveguide on the top silicon layer of the silicon-on-insulator substrate, wherein the delay line waveguide is a silicon waveguide; forming a doped region in the delay line waveguide, and the refractive index of the doped region is different from the refractive index of other regions in the delay line waveguide except the doped region.

[0009] In the embodiments of the present application, by adopting the method of adding a doped region in the delay line waveguide, the wavelength division multiplexing system includes: an input waveguide, a beam splitter connected to the input waveguide, a delay line waveguide connected to at least one output end of the beam splitter, and an output waveguide connected to the delay line waveguide, wherein the waveguide material of the input waveguide is the top silicon in the silicon-on-insulator substrate; the delay line waveguide is a silicon waveguide, the delay line waveguide includes a doped region, and the refractive index of the doped region is different from the refractive index of other regions in the delay line waveguide except the doped region. Since the refractive index of the doped region is different from the refractive index of other regions in the delay line waveguide except the doped region, the resonant wavelength can be non-volatilely adjusted to the required value, solving the problem of wavelength shift caused by processing reasons in the wavelength division multiplexing system in the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The drawings here are incorporated into the specification and form a part of this specification, showing the embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings.

[0012] Figure 1 is a schematic structural diagram of an optional wavelength division multiplexing system according to the embodiments of the present application;

[0013] Figure 2 is a schematic diagram of an optional integration of a thermal tuner in a delay line to compensate for the phase error of a WDM system according to the embodiments of the present application;

[0014] Figure 3 It is a schematic diagram for comparison before and after phase calibration according to an optional embodiment of the present application;

[0015] Figure 4 It is a schematic diagram for doping Ge ions in a waveguide and annealing according to an optional embodiment of the present application;

[0016] Figure 5 It is a schematic diagram for comparison before and after processing according to an optional embodiment of the present application;

[0017] Figure 6 It is a schematic diagram of an optional on-chip wavelength division multiplexing system according to an embodiment of the present application;

[0018] Figure 7 It is a partial schematic diagram of an optional on-chip wavelength division multiplexing system according to an embodiment of the present application;

[0019] Figure 8 It is a schematic diagram of the structure of an optional Mach-Zehnder filter according to an embodiment of the present application;

[0020] Figure 9 It is a schematic diagram of an optional transmission spectrum according to an embodiment of the present application;

[0021] Figure 10 It is a schematic diagram for comparison before and after correction according to an optional embodiment of the present application;

[0022] Figure 11 It is a schematic flow diagram of a preparation method for an optional wavelength division multiplexing component according to an embodiment of the present application. Detailed implementation manners

[0023] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0024] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of this application are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, wavelength division multiplexing system, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, wavelength division multiplexing systems, products or devices.

[0025] According to one aspect of the embodiments of the present application, a wavelength division multiplexing system is provided. As Figure 1 shown, the wavelength division multiplexing system includes: an input waveguide, a beam splitter connected to the input waveguide, a delay line waveguide connected to at least one output end of the beam splitter, and an output waveguide connected to the delay line waveguide, wherein the waveguide material of the input waveguide is the top silicon in a silicon-on-insulator substrate; the delay line waveguide is a silicon waveguide, and the delay line waveguide includes a doped region, and the refractive index of the doped region is different from the refractive index of other regions in the delay line waveguide except the doped region.

[0026] In this embodiment, the wavelength division multiplexing system can be applied to the scenario of calibrating the wavelength offset of the wavelength division multiplexing system. Wavelength division multiplexing is an effective means for improving optical communication capacity. At the same time, combined with a photon integration chip, it can effectively reduce the size of the device and improve the integration of the system. Its key devices are wavelength division multiplexing devices and wavelength demultiplexing devices.

[0027] Generally speaking, a wavelength division multiplexing system can include optical fibers, wavelength division multiplexers, wavelength division demultiplexers, optical receivers, etc. Specifically, an optical fiber can be used as a medium for transmitting optical signals and can transmit multiple optical signals. A wavelength division multiplexer can be used to combine multiple optical signals with different wavelengths into one optical signal for transmission in an optical fiber. A wavelength division demultiplexer can be used to extract different wavelength optical signals from the optical fiber and separate them into their respective signals. An optical receiver can be used to receive the demultiplexed optical signals and convert them into electrical signals. In a wavelength division multiplexing system, if 4 optical signals with different wavelengths need to be transmitted, then first these optical signals will be combined by a wavelength division multiplexer and then transmitted through an optical fiber. At the receiving end, the optical signals will be separated by a wavelength division demultiplexer and converted into electrical signals through an optical receiver. In this way, multiplexing and demultiplexing of multiple optical signals can be achieved.

[0028] It is understandable that a wavelength division multiplexing system is a technology that multiplexes multiple signals of different frequencies onto the same optical fiber or waveguide through different wavelengths. Specifically, it can include the following steps:

[0029] Step 1, input signals: Multiple optical signals of different frequencies are input into the wavelength division multiplexer. These signals can come from different light sources or modulated optical signals.

[0030] Step 2, beam splitting: The wavelength division multiplexer separates the input signals into different wavelengths through a series of gratings or filters.

[0031] Step 3, multiplexing: The separated signals are recombined into a composite signal, where each signal corresponds to a different wavelength.

[0032] Step 4, output signals: The composite signal is transmitted to the target location through the output waveguide, and these signals can be separated into individual wavelength signals again.

[0033] For example, assume there are three input signals which are red, green, and blue optical signals respectively. These signals are input into the wavelength division multiplexer. After beam splitting and multiplexing, the output composite signal contains red, green, and blue optical signals. This composite signal is transmitted to the target location through the output waveguide and then separated into red, green, and blue individual wavelength signals again.

[0034] However, since the optical waveguide devices in the silicon-based wavelength division multiplexer are affected by changes in width, inclination caused by the processing technology, changes in the thickness of the silicon wafer waveguide, and temperature changes, etc., it causes the offset of the central wavelength of the silicon-based wavelength division multiplexing device. In addition, for high-channel number architectures, additional delay lines are required for step-by-step demultiplexing, resulting in a further increase in the total signal propagation length and the accumulation of phase errors. It can be seen that the wavelength division multiplexing system in the related technology has the problem of wavelength offset caused by processing reasons.

[0035] To at least partially solve the above problems, in this embodiment, a method of adding a doped region in the delay line waveguide is adopted. Since the refractive index of the doped region is different from that of other regions in the delay line waveguide except the doped region, the resonant wavelength can be non-volatilely adjusted to the required value by changing the refractive index of the doped region, thus solving the problem of wavelength offset caused by processing reasons in the wavelength division multiplexing system in the related technology.

[0036] Here, the delay-line waveguide is a device used in a wavelength-division multiplexing system, which can be used to delay the transmission time of optical signals. The delay-line waveguide is usually made of a material with a specific refractive index, and can release the optical signal after it has been transmitted therein for a certain period of time. The function of the delay-line waveguide is to adjust the transmission delay time of optical signals with different wavelengths in the wavelength-division multiplexing system, so that they can be synchronized to the same time point at the receiving end, thereby avoiding mutual interference between wavelengths. The refractive index of the delay-line waveguide affects the speed at which the optical signal is transmitted therein, and delay-line waveguides with different refractive indices can achieve different delay times. Therefore, selecting a delay-line waveguide with an appropriate refractive index is of great significance for signal synchronization and adjustment in the wavelength-division multiplexing system.

[0037] According to the present application, the wavelength-division multiplexing system includes: an input waveguide, a beam splitter connected to the input waveguide, a delay-line waveguide connected to at least one output end of the beam splitter, and an output waveguide connected to the delay-line waveguide, wherein the waveguide material of the input waveguide is the top silicon in a silicon-on-insulator substrate; the delay-line waveguide is a silicon waveguide, and the delay-line waveguide includes a doped region, and the refractive index of the doped region is different from the refractive index of other regions in the delay-line waveguide except the doped region, which can solve the problem of wavelength shift caused by processing reasons in the related art wavelength-division multiplexing system.

[0038] In an exemplary embodiment, the doped region is doped with at least one of the following ions: germanium ions, bismuth ions, nitrogen ions, phosphorus ions, potassium ions, silver ions, boron ions.

[0039] Optionally, the doped region can be doped with one or more ions, and the concentration of the doped ions is not limited in this embodiment, and the concentrations of different ions can be the same or different.

[0040] For example, in this embodiment, taking the implantation of a certain concentration of germanium (Ge) ions in the delay-line waveguide as an example, since implanting Ge will cause disorder in the silicon lattice and change the microstructure of the exposed area of the silicon waveguide, making it change from a crystal to an amorphous state, thereby changing the refractive index of the doped region.

[0041] Through this embodiment, by doping ions in the doped region, the refractive index of the doped region can be changed.

[0042] In an exemplary embodiment, the wavelength-division multiplexing system further includes: a heating structure located above the doped region, which is used to perform annealing treatment on the doped region so that the amorphous silicon in the doped region recrystallizes.

[0043] Currently, a widened waveguide in a delay line can be utilized to mitigate phase error. However, the impact of the widened waveguide on mitigating phase error is quite limited, and the effect of this method is very limited for some low-process technology platforms. Based on this, a more effective method is to integrate a thermal tuner in the delay line to compensate for the phase error (as Figure 2 shown). Since silicon has a large thermo-optic coefficient, this can also achieve compensation for the phase error. An adjustable thermo-optic phase shifter can be integrated in a specific delay line of the filter for phase control (as Figure 3 shown), Figure 3 In , the fab measurement can refer to the spectral analysis and measurement of an optical signal through a spectrum analyzer or other instruments. This can help determine the frequency and power characteristics of optical signals at different wavelengths in a wavelength-division multiplexing system, thereby assisting in system performance evaluation and fault diagnosis. However, even with the integration of the thermo-optic phase shifter, for a multi-channel filter, manual phase adjustment for each delay line is time-consuming, and the thermal crosstalk between thermal tuners makes the phase adjustment procedure complex and cumbersome.

[0044] To solve the above technical problems, in this embodiment, through a heating structure located above a doped region in a wavelength-division multiplexing system, annealing treatment is performed on the doped region by the heating structure, which can recrystallize the amorphous silicon in the doped region and permanently adjust its refractive index.

[0045] For example, in this embodiment, a part of the delay line contains a doped region, and the doped region will be doped with a certain concentration of Ge ions. There is a heating structure of a certain length above the doped region for heating the doped region (annealing treatment). In an exemplary embodiment, the heating structure can include at least one of the following: a thermo-optic phase shifter, a heating sheet, and the thermo-optic phase shifter includes at least one of the following electrodes: a titanium nitride metal electrode, a tungsten electrode, as Figure 4 shown, Figure 4 shows a schematic diagram of doping Ge ions in a waveguide and annealing, Figure 5 shows a comparison schematic diagram before and after treatment.

[0046] Through this embodiment, by annealing the doped region at a sufficiently high temperature through the heating structure, the amorphous silicon in the waveguide can be recrystallized and its refractive index can be permanently changed.

[0047] In an exemplary embodiment, the wavelength-division multiplexing system further includes:

[0048] a control component for controlling the annealing temperature and duration of the annealing treatment of the doped region by the heating structure to adjust the refractive index of the doped region to a specified value.

[0049] For example, in this embodiment, by using an integrated on-chip heater to control the annealing temperature and duration, the refractive index can be precisely adjusted to adjust the refractive index of the doped region to a specified value, and thus the resonant wavelength can be adjusted after manufacturing. Here, the specified value can be pre-set or a value dynamically adjusted according to the detected refractive index, and this embodiment does not limit this.

[0050] In an exemplary embodiment, the waveguide thickness of the input waveguide ranges from 140 nm to 400 nm, and the width of the input waveguide ranges from 350 nm to 1500 nm.

[0051] For example, in this embodiment, the waveguide material is the top layer silicon Si in an SOI (Silicon on Insulator) substrate, with a typical thickness of 220 nm and a typical width of 500 nm (TE single-mode waveguide, Transverse Electric mode waveguide, a waveguide mode that only supports the transmission of the transverse electric field component).

[0052] In an exemplary embodiment, the beam splitter includes at least one of the following: at least one 2×2 multimode interference coupler, a directional coupler.

[0053] For example, in combination Figure 6 and Figure 7 , in this embodiment, the beam splitter is generally composed of a 2×2 MMI or a directional coupler. The MMI (multimode interferometer) coupler is usually composed of optical waveguides and is used for optical distribution and coupling in optical communication and optical sensors. It can distribute the input optical signal to multiple output channels and can achieve optical multiplexing and demultiplexing. The directional coupler can be used to couple and transmit an optical signal from one waveguide to another while maintaining as high an optical transmission efficiency as possible. It is usually used in fiber optic communication systems and integrated optical devices for coupling and distributing optical signals.

[0054] In an exemplary embodiment, the number of beam splitters is multiple, and the multiple beam splitters form a hierarchical beam splitter. A delay line waveguide is connected to an output end of at least some of the beam splitters.

[0055] Here, the hierarchical beam splitter can be composed of two or more beam splitters. Through the hierarchical beam splitter, the input optical signal can be hierarchically separated according to different wavelengths. This hierarchical separation can help distribute optical signals of different wavelengths to different channels or paths for processing or transmission in the system. Through the hierarchical beam splitter, the separation and processing of multiple optical signals can be effectively achieved, thereby improving the signal processing ability and efficiency of the system.

[0056] In an exemplary embodiment, the delay line waveguide is a single-mode silicon ridge waveguide or a single-mode strip waveguide. Here, the single-mode silicon ridge waveguide is an optical waveguide structure for optical communication and optoelectronic devices, usually made of silicon material, having a certain refractive index and transmission characteristics. The single-mode silicon ridge waveguide can support the transmission of a single optical mode and can be used to fabricate optical devices such as optical waveguide couplers, optical modulators, and optical detectors to achieve the transmission and processing of optical signals. The single-mode strip waveguide is an optical waveguide structure that can confine the optical transmission mode so that only one mode can be transmitted therein. This waveguide structure is usually used in wavelength division multiplexing devices in fiber optic communication systems to separate and integrate optical signals of different wavelengths.

[0057] As an alternative exemplary embodiment of the present application, the present application is explained by taking a cascaded Mach-Zehnder interferometer (MZI) as an example.

[0058] In recent years, silicon photonics has experienced a sharp growth because it provides the integration of chip-level photonics and CMOS (Complementary Metal-Oxide-Semiconductor) functions in high-volume processes. Wavelength filters are considered key optical components in telecommunication and computing systems and have been implemented on all-silicon platforms. Specifically, those filters fabricated on silicon-on-insulator (SOI) wafers are usually based on arrayed waveguide gratings, microring resonators, and cascaded Mach-Zehnder interferometers (MZIs). Among them, the MZI-based wavelength filters have excellent losses, better manufacturing tolerances, and simple channel scalability.

[0059] An ordinary 2 M channel MZI filter is composed of M wavelength interleaving devices cascaded. To achieve the best transmission characteristics, it is necessary to precisely control the phase shift of each interleaving device to ensure that their spectral positions are consistent and there is sufficient isolation between channels. However, due to the high refractive index contrast of silicon waveguides in SOI, such devices are usually affected by random effective refractive index fluctuations caused by processing errors. This is one of the main factors leading to the difficulty in implementing MZI filters. In addition, for high-channel-number architectures, additional delay lines are required for step-by-step demultiplexing, resulting in a further increase in the total signal propagation length and a serious accumulation of phase errors.

[0060] Generally, a wavelength division multiplexing (WDM) filter for multiplexing or demultiplexing includes: a first frequency shaping unit, including: two or more cascaded units, each unit including a 2×2 coupler that cross-couples two input ports to two output ports according to a predetermined coupling ratio and is connected to a phase delay component that applies a relative phase delay between two paths according to a predetermined phase difference; and a second frequency shaping unit including: two or more cascaded units, each unit including a 2×2 coupler that cross-couples two input ports to two output ports according to a predetermined coupling ratio and is connected to a phase delay component that applies a relative phase delay between two paths according to a predetermined phase difference.

[0061] In another aspect, generally, a wavelength division multiplexing (WDM) transceiver system that supports light waves of different respective channel wavelengths includes: a first transmitter subsystem, including: a first wavelength division multiplexer including a plurality of multi-stage Mach-Zehnder interferometers, each of which includes a plurality of first-order Mach-Zehnder interferometers, a plurality of light sources and / or ports that provide light waves of a plurality of wavelengths, and a plurality of optical modulators configured to modulate the light waves and provide the modulated light waves to the first wavelength division multiplexer; and a first receiver subsystem, including: a first wavelength division multiplexer including a plurality of multi-stage Mach-Zehnder interferometers, each of which includes a plurality of first-order Mach-Zehnder interferometers, a second wavelength division multiplexer including a plurality of multi-stage Mach-Zehnder interferometers, each of which includes a plurality of first-order Mach-Zehnder interferometers, configured to provide a first input light wave to the first wavelength division multiplexer and a second input light wave to the second wavelength division multiplexer; a tuning module including a plurality of photodetectors configured to monitor the power before and after the first wavelength division multiplexer, before and after the first wavelength division multiplexer, and before and after the second wavelength division multiplexer, and circuitry configured to adjust the center wavelength of the channel at least in part based on adjusting the relative optical output power of each output port of the plurality of first-order Mach-Zehnder interferometers in the first wavelength division multiplexer, the first wavelength division multiplexer, and the second wavelength division multiplexer. To achieve optimal transmission characteristics, precise control of the phase shift of each interleaver is required to ensure that their spectral positions are consistent and that there is sufficient isolation between channels. However, due to the high refractive index contrast of silicon waveguides in SOI, such devices are typically affected by random effective refractive index fluctuations caused by processing errors.

[0062] This application constructs a Mach-Zehnder lattice filter composed of cascaded directional couplers with different coupling coefficients and delay lines of the same length, as Figure 8As shown. The length of the coupler is calculated from the filter coefficients of the Kaiser window and then mapped to the coupling coefficient of the directional coupler. The performance of the filter is determined by the accurate coupling ratios that distribute the light to different paths of the filter. Additionally, the same phase and time delay should be introduced in all stages. Errors in coupling and phase delay will result in higher insertion loss and crosstalk levels, as well as a shift in the filter passband. Combining Figure 8 , a schematic diagram of the structure of the Mach-Zehnder lattice filter. According to the filter coefficients, the coupling coefficient of the directional coupler can be calculated and then converted into the coupling length.

[0063] Combining Figure 9 , the effects of changes in the simulated waveguide width and thickness on an 8-stage MZI lattice filter were simulated. 277 Monte Carlo samples were simulated. Figure 9 Shows the transmission spectra of the filter passband (dashed line) and rejection band (solid line).

[0064] This application provides an on-chip wavelength division multiplexing system, including: an input waveguide, a beam splitter, a delay line, a doped region, a thermo-optic phase shifter, and an output waveguide. By implanting Ge in the delay line waveguide and placing a heater above it for post-fabrication thermal annealing, the effective refractive index of a small part of the delay line waveguide is changed. Implanting Ge causes disorder in the silicon lattice and changes the microstructure of the exposed area of the silicon waveguide, making it change from crystalline to amorphous, thus changing the refractive index of the implanted region. Annealing these doped regions at a high enough temperature can recrystallize the amorphous silicon in the waveguide and permanently change its refractive index. Therefore, by using an integrated on-chip heater to control the annealing temperature and duration, we can precisely adjust the refractive index and thus the resonant wavelength of the WDM after fabrication. As we described earlier, this adjustment process can be fully automated and applied to all WDM components on the entire SOI wafer to precisely and non-volatilely adjust their resonant wavelengths to the desired values. Figure 10 Shows a comparison schematic diagram before and after correction.

[0065] Through this application, the phase noise caused by inconsistent waveguide width or thickness due to processing reasons in the WDM system can be reduced, and the wavelength offset of the WDM system can be calibrated; the solution of this application provides a non-volatile resonant wavelength regulation method, which can correct the manufacturing errors by permanently changing the refractive index of the waveguide or cladding material after the device is manufactured, improving the processing yield of the WDM system; the WDM system adopting this solution does not require an additional calibration process and adjustment device during operation, and can achieve zero power consumption operation of the entire system.

[0066] According to another aspect of the embodiments of the present application, there is provided a wavelength division multiplexing transceiver system, including: at least one wavelength division multiplexing component disposed on a silicon-on-insulator wafer, and the wavelength division multiplexing component includes the wavelength division multiplexing system of any one of the above.

[0067] In an exemplary embodiment, the wavelength division multiplexing component is a Mach-Zehnder interferometer (MZI) filter with 2 M channels, and the MZI filter includes M cascaded wavelength interleaving devices.

[0068] Wavelength filters are considered key optical components in telecommunication and computing systems and have been implemented on all-silicon platforms. Specifically, filters fabricated on SOI (Silicon on Insulator) wafers are typically based on arrayed waveguide gratings, microring resonators, and MZIs (Mach-Zehnder interferometers). Among them, MZI-based wavelength filters have excellent loss, better manufacturing tolerances, and simple channel scalability. Taking the MZI filter as an example, a common 2 M channel MZI filter is composed of M cascaded wavelength interleaving devices.

[0069] Here, a wavelength interleaving device may refer to a device for interleaving optical signals of multiple different wavelengths. A wavelength interleaving device usually consists of waveguides with multiple channels, and each waveguide corresponds to a specific wavelength. The function of the wavelength interleaving device is to combine these optical signals of different wavelengths into a composite optical signal for transmission in an optical fiber communication system.

[0070] Specifically, a wavelength interleaving device can combine optical signals of multiple different wavelengths through different channels into a composite optical signal and then transmit it through a single optical fiber. At the receiving end, the composite optical signal is decomposed into different wavelength components through a wavelength separator. Such a design can effectively improve the transmission capacity of the optical fiber communication system, allowing multiple signals of different wavelengths to be transmitted through the same optical fiber, thereby improving the flexibility and efficiency of the system.

[0071] It should be noted that for the foregoing embodiments of the wavelength division multiplexing system, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present application is not limited by the described action sequence, because according to the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present application.

[0072] According to yet another aspect of the embodiments of the present application, there is also provided a method for preparing a wavelength division multiplexing component,Figure 11 FIG. Figure 11 is a schematic flowchart of a method for manufacturing an optional wavelength division multiplexing component according to an embodiment of the present application. As Figure 11 shown, the process of this method may include the following steps:

[0073] S1102, providing a silicon-on-insulator substrate;

[0074] A silicon-on-insulator substrate is a substrate material used in silicon-based integrated optical circuits. The role of the silicon-on-insulator substrate is to provide an insulating base on an optical chip for supporting and isolating optical components on the optical chip. In an optical chip, the silicon-on-insulator substrate can effectively isolate the interference between optical components and other electronic components. In addition, it can also provide good optical performance and stability, reduce the coupling loss between optical components and the substrate, thereby improving the performance and stability of the entire optical system. Generally speaking, the silicon-on-insulator substrate plays a role in supporting and isolating optical components in a wavelength division multiplexing system, which helps to improve the performance and stability of the system.

[0075] Here, the silicon-on-insulator substrate can be provided by a robotic arm or other control components. The silicon-on-insulator substrate is placed on the insulator on the operating table. The silicon-on-insulator substrate can be pre-produced and placed at a designated position, or other ways of providing the silicon-on-insulator substrate can be adopted.

[0076] S1104, forming an input waveguide, a beam splitter connected to the input waveguide, a delay line waveguide connected to at least one output end of the beam splitter, and an output waveguide connected to the delay line waveguide on the top silicon layer of the silicon-on-insulator substrate, wherein the delay line waveguide is a silicon waveguide;

[0077] An optical device structure layer can be formed on the top silicon layer of the provided silicon-on-insulator substrate. For example, the optical device structure layer can include an input waveguide, a beam splitter connected to the input waveguide, a delay line waveguide connected to at least one output end of the beam splitter, and an output waveguide connected to the delay line waveguide.

[0078] S1106, forming a doped region in the delay line waveguide, wherein the refractive index of the doped region is different from the refractive index of other regions in the delay line waveguide except for the doped region.

[0079] It should be noted that the above steps S1102 to S1106 can be used to obtain the wavelength division multiplexing system in the foregoing embodiments, which have been described and will not be elaborated here.

[0080] Through the above steps S1102 to S1106, a silicon-on-insulator substrate is provided; an input waveguide, a beam splitter connected to the input waveguide, a delay line waveguide connected to at least one output end of the beam splitter, and an output waveguide connected to the delay line waveguide are formed on the top silicon layer of the silicon-on-insulator substrate, wherein the delay line waveguide is a silicon waveguide; a doped region is formed in the delay line waveguide, and the refractive index of the doped region is different from that of other regions in the delay line waveguide except the doped region, solving the problem of wavelength shift caused by processing reasons in the related wavelength division multiplexing system.

[0081] In an exemplary embodiment, the above method further includes:

[0082] A heating structure is disposed above the doped region;

[0083] Controlling the heating structure to perform annealing treatment on the doped region so that the amorphous silicon in the doped region recrystallizes.

[0084] For example, in this embodiment, a part of the delay line contains a doped region, and the doped region will be doped with a certain concentration of Ge ions. There is a thermo-optic phase shifter with a certain length above the doped region for heating the doped region (annealing treatment). Annealing these doped regions at a sufficiently high temperature can cause the amorphous silicon in the waveguide to recrystallize and change its refractive index.

[0085] In an exemplary embodiment, controlling the heating structure to perform annealing treatment on the doped region includes:

[0086] Controlling the heating structure to perform annealing treatment on the doped region according to a set annealing temperature and duration to adjust the refractive index of the doped region to a specified value.

[0087] Here, the annealing temperature and duration can be preset fixed values, or can be dynamically adjusted based on the detected refractive index or related parameters, and thus the refractive index of the doped region can be adjusted to a specified value.

[0088] For example, in this embodiment, by using an integrated on-chip heater to control the annealing temperature and duration, the refractive index can be precisely adjusted.

[0089] In the above embodiments of the present application, the descriptions of the respective embodiments have their own focuses. For parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0090] The unit described as a separation component may or may not be physically separated. The component shown as a unit may or may not be a physical unit, that is, it may be located in one place or distributed across multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution provided in this embodiment.

[0091] In addition, each functional unit in various embodiments of the present application can be integrated into a processing unit, or each unit can exist physically alone, or at least two units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0092] The above are only the preferred embodiments of the present application. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A wavelength division multiplexing system, characterized in that, Comprising: An input waveguide, a beam splitter connected to the input waveguide, a delay line waveguide connected to at least one output end of the beam splitter, and an output waveguide connected to the delay line waveguide, wherein, The waveguide material of the input waveguide is the top silicon in a silicon-on-insulator substrate; The delay line waveguide is a silicon waveguide, the delay line waveguide includes a doped region, and the refractive index of the doped region is different from the refractive index of other regions in the delay line waveguide except the doped region.

2. The wavelength division multiplexing system according to claim 1, characterized in that The doped region is doped with at least one of the following ions: germanium ions, bismuth ions, nitrogen ions, phosphorus ions, potassium ions, silver ions, boron ions.

3. The wavelength division multiplexing system according to claim 1, wherein The wavelength division multiplexing system further includes: a heating structure located above the doped region, configured to anneal the doped region to recrystallize the amorphous silicon in the doped region.

4. The wavelength division multiplexing system according to claim 3, wherein The heating structure includes at least one of the following: a thermo-optic phase shifter, a heating sheet.

5. The wavelength division multiplexing system according to claim 3, characterized in that, The wavelength division multiplexing system further includes: a control component, configured to control the annealing temperature and duration of the annealing process of the doped region by the heating structure to adjust the refractive index of the doped region to a specified value.

6. The wavelength division multiplexing system according to claim 1, wherein The beam splitter includes at least one of the following: at least one 2×2 multimode interference coupler, a directional coupler.

7. The wavelength division multiplexing system according to claim 6, wherein The number of the beam splitters is multiple, and the multiple beam splitters form a hierarchical beam splitter, and at least one output end of at least part of the beam splitters is connected to one of the delay line waveguides.

8. The wavelength division multiplexing system according to any one of claims 1 to 7, characterized in that, The delay line waveguide is a single-mode silicon ridge waveguide or a single-mode strip waveguide.

9. A wavelength division multiplexing transceiver system, characterized in that, Comprising: At least one wavelength division multiplexing component disposed on a silicon-on-insulator wafer, the wavelength division multiplexing component including the wavelength division multiplexing system according to any one of claims 1 to 8.

10. The wavelength division multiplexing transceiver system according to claim 9, wherein Comprising: The wavelength division multiplexing component is 2 M Mach-Zehnder interferometer MZI filters for channels, and the MZI filters include M cascaded wavelength interleavers.

11. A method for manufacturing a wavelength division multiplexing component, characterized in that, Providing a silicon-on-insulator substrate; Forming an input waveguide, a beam splitter connected to the input waveguide, a delay line waveguide connected to at least one output end of the beam splitter, and an output waveguide connected to the delay line waveguide on the top silicon layer of the silicon-on-insulator substrate, wherein the delay line waveguide is a silicon waveguide; Forming a doped region in the delay line waveguide, wherein the refractive index of the doped region is different from the refractive index of other regions in the delay line waveguide except the doped region.

12. The preparation method according to claim 11, characterized in that, The method further includes: Providing a heating structure above the doped region; Controlling the heating structure to anneal the doped region to recrystallize the amorphous silicon in the doped region.

13. The preparation method according to claim 12, wherein The controlling the heating structure to anneal the doped region includes: Controlling the heating structure to anneal the doped region according to a set annealing temperature and duration to adjust the refractive index of the doped region to a specified value.

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