Optical interconnection system on optical chip and optical chip

Abstract

The invention discloses an optical interconnection system on an optical chip and the optical chip, relates to the technical field of communication, and aims to solve the technical problem of low system data capacity in the wavelength division multiplexing technology in the prior art. The system comprises a micro-ring modulation device, a polarization combiner and a demultiplexer, the output end of the micro-ring modulation device is connected with the input end of the polarization combiner; the input end of the demultiplexer is connected with the output end of the polarization combiner; the micro-ring modulation device is used for performing signal modulation on TE0 polarized light and TM0 polarized light in the light source; the polarization combiner is used for combining the TE0 polarized light and the TM0 polarized light output by the micro-ring modulation device and outputting combined light; and the demultiplexer is used for decomposing the combined light into signals corresponding to a plurality of wavelengths. By combining the polarization multiplexing technology and the wavelength division multiplexing technology, the number of multiplexing channels of the optical interconnection system is multiplied, and the data capacity of the optical interconnection system is improved.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and in particular, to an optical interconnection system and an optical chip on an optical chip. Background Art

[0002] The communication method on traditional optical chips often adopts electrical interconnection technology. However, with the improvement of data transmission and processing requirements, the bandwidth of traditional electrical interconnection is difficult to meet the demand. In contrast, optical interconnection has advantages such as higher bandwidth, lower system power consumption, and strong anti-interference ability.

[0003] Wavelength division multiplexing is a communication method for realizing high-speed optical interconnection in an optical chip. It uses light waves of different wavelengths to carry each sub-channel, and multiple multiplexed channels transmit all wavelengths simultaneously. In an optical chip, by designing a specific waveguide structure and micro-ring modulator, these light signals of different wavelengths can be transmitted in parallel in the same waveguide without interfering with each other.

[0004] As an important optical component, the micro-ring modulator plays a key role in the wavelength division multiplexing system. It can modulate the light signal of a specific wavelength by changing parameters such as the refractive index of the ring waveguide, thereby realizing independent control and processing of light signals of different wavelengths.

[0005] However, the single wavelength division multiplexing technology still limits the improvement of the data capacity of the optical interconnection system in the entire chip. Summary of the Invention

[0006] The purpose of the present invention is to provide an optical interconnection system and an optical chip on an optical chip to solve the technical problem of low system data capacity existing in the wavelength division multiplexing technology in the prior art.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] In a first aspect, the present invention provides an optical interconnection system on an optical chip, including:

[0009] A micro-ring modulation device, a polarization combiner, and a demultiplexer;

[0010] The output end of the micro-ring modulation device is connected to the input end of the polarization combiner; the input end of the demultiplexer is connected to the output end of the polarization combiner;

[0011] The micro-ring modulation device is used to modulate the TE 0 polarized light and TM 0 polarized light in the light source;

[0012] The polarization combiner is used to combine the TE 0 polarized light and TM 0Combine polarized light and output the combined light;

[0013] The demultiplexer is used to decompose the combined light into signals corresponding to multiple wavelengths.

[0014] Optionally, the optical interconnection system on the optical chip further includes: a first polarization beam splitter and a second polarization beam splitter; the output end of the first polarization beam splitter is connected to the input end of the micro-ring modulation device; the input port of the second polarization beam splitter is connected to the output port of the demultiplexer;

[0015] The first polarization beam splitter is used to decompose the light source into the TE 0 polarized light and the TM 0 polarized light;

[0016] The second polarization beam splitter is used to perform polarization beam splitting on the signal corresponding to each wavelength output by the demultiplexer.

[0017] Optionally, each micro-ring modulator in the micro-ring modulation device includes at least a plurality of micro-ring series structures;

[0018] Each micro-ring series structure includes a first micro-ring structure and a second micro-ring structure connected in series;

[0019] The first micro-ring structure is used to modulate the signal to be modulated corresponding to the wavelength, and the second micro-ring structure is used to perform phase shift on the modulated signal.

[0020] Optionally, a PN junction is provided on the first micro-ring structure; the PN junction is used to load an electrical signal on the optical signal to complete preliminary signal modulation.

[0021] Optionally, the plurality of micro-ring series structures are arranged in an array form.

[0022] Optionally, each micro-ring modulator further includes a first waveguide, a first optical splitter, and a first combiner;

[0023] The first end of the first waveguide is connected to the first optical splitter; the second end of the first waveguide is connected to the first combiner; the first optical splitter is used to decompose the TE 0 polarized light or the TM 0 polarized light into two signals with equal power; each of the two signals includes signals to be modulated corresponding to multiple wavelengths;

[0024] All the first micro-ring structures in the plurality of micro-ring series structures are connected to the first waveguide; the first waveguide is used to introduce the two signals into the plurality of micro-ring series structures and transmit the signals after modulation by the plurality of micro-ring series structures to the first combiner.

[0025] Optionally, each microring modulator further includes a second waveguide, a third waveguide, a fourth waveguide, a second optical splitter, and a second beam combiner; the plurality of microring series structures include a first-row microring series structure and a second-row microring series structure;

[0026] One end of the second waveguide and one end of the third waveguide are both connected to the second optical splitter;

[0027] All the first microring structures in the first-row microring series structure are connected to the second waveguide; the second waveguide is used to introduce the first path of the two paths of signals split by the second optical splitter into the first-row microring series structure;

[0028] All the first microring structures in the second-row microring series structure are connected to the third waveguide; the third waveguide is used to introduce the second path of the two paths of signals split by the second optical splitter into the second-row microring series structure;

[0029] All the second microring structures in the plurality of microring series structures are connected to the fourth waveguide;

[0030] One end of the fourth waveguide is connected to the second beam combiner; the fourth waveguide is used to transmit the signal after final modulation to the second beam combiner;

[0031] The second beam combiner is used to combine the signals after final modulation.

[0032] Optionally, each microring modulator in the microring modulation device includes a plurality of microring combination structures, a fifth waveguide, a sixth waveguide, a seventh waveguide, an interlayer coupler, and a third beam combiner;

[0033] Each microring combination structure includes a third microring structure, a fourth microring structure, and a fifth microring structure; the fourth microring structure is connected to the third microring structure; the fifth microring structure is connected to the third microring structure and the fifth microring structure is located above the third microring structure;

[0034] Both the third microring structure and the fourth microring structure are located between the fifth waveguide and the sixth waveguide;

[0035] The third microring structure is connected to the fifth waveguide; the fifth waveguide is used to introduce the TE 0 polarized light or the TM 0 polarized light into the third microring structure; the third microring structure is used to load the electrical signal onto the TE 0 polarized light or the TM 0 polarized light to complete preliminary signal modulation;

[0036] The fourth micro-ring structure is connected to the sixth waveguide, and the fourth micro-ring structure is used for phase-shifting the preliminarily modulated signal;

[0037] The fifth micro-ring structure is connected to the seventh waveguide, and the fifth micro-ring structure is used for phase-shifting the modulated signal;

[0038] The end of the seventh waveguide is connected to the third beam combiner through the interlayer coupler;

[0039] The end of the sixth waveguide is connected to the third beam combiner.

[0040] Optionally, the relationship between the resonant wavelength and the micro-ring radius in the first micro-ring structure is:

[0041]

[0042] where λ is the resonant wavelength, n eff is the effective refractive index, R is the micro-ring radius of the first micro-ring structure, and m is a positive integer greater than or equal to 1;

[0043] The round-trip phase shift of the second micro-ring structure is:

[0044] θ = βL; where, L = 2πR; β is the propagation constant, and L is the length of the second micro-ring structure.

[0045] Compared with the prior art, in an optical interconnection system on an optical chip provided by the present invention, the micro-ring modulation device modulates the TE 0 polarized light and TM 0 polarized light in the light source, and then the polarization multiplexing technology is preliminarily completed. Then, the polarization combiner combines the two polarized lights after signal modulation and transmits them to the demultiplexer. The demultiplexer then separates the combined signal according to the number of wavelengths, and obtains signals corresponding to multiple wavelengths (for example, Figure 1 i wavelengths in), that is, the demultiplexer independently completes the wavelength division multiplexing technology. Thus, the optical interconnection system on the optical chip in the embodiment of the present invention couples the polarization multiplexing technology and the wavelength division multiplexing technology together, doubling the number of multiplexing channels of the optical interconnection system, so that the amount of data that can be transmitted per unit time also doubles, greatly improving the data capacity of the optical interconnection system.

[0046] In a second aspect, the present invention also provides an optical chip, including the optical interconnection system on an optical chip described in any one of the above. Description of the Drawings

[0047] The accompanying drawings described herein are used to provide a further understanding of the present invention and form a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0048] Figure 1 Schematic diagram of the optical interconnection system structure on an optical chip provided for an embodiment of the present invention;

[0049] Figure 2 Channel schematic diagram of the optical interconnection system on an optical chip provided for an embodiment of the present invention;

[0050] Figure 3 Schematic diagram of the structure of a microring modulator provided for a specific embodiment of the present invention;

[0051] Figure 4 Schematic diagram of the structure of a QPSK modulator provided for an embodiment of the present invention;

[0052] Figure 5 Schematic diagram of the structure of a microring modulator provided for another specific embodiment of the present invention;

[0053] Figure 6 Schematic diagram of the structure of a microring modulator provided for yet another specific embodiment of the present invention;

[0054] Figure 7 Schematic diagram of the structure of a signal demodulation device provided for an embodiment of the present invention.

[0055] Reference numerals: 10 - microring modulation device; 20 - polarization combiner; 30 - demultiplexer; 40 - first polarization beam splitting device; 50 - second polarization beam splitting device; 100 - microring modulator; 110 - microring series structure; 111 - first microring structure; 112 - second microring structure; 113 - PN junction; 120 - first waveguide; 121 - second waveguide; 122 - third waveguide; 123 - fourth waveguide; 124 - fifth waveguide; 125 - sixth waveguide; 126 - seventh waveguide; 130 - first optical splitter; 140 - first combiner; 131 - second optical splitter; 141 - second combiner; 142 - third combiner; 150 - microring combination structure; 151 - third microring structure; 152 - fourth microring structure; 153 - fifth microring structure; 160 - interlayer coupler. Detailed implementation manners

[0056] For the convenience of clearly describing the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, terms such as "first" and "second" are used to distinguish identical or similar items with basically the same functions and effects. For example, the first threshold and the second threshold are only used to distinguish different thresholds, and do not limit their sequence. Those skilled in the art can understand that terms such as "first" and "second" do not limit the quantity and execution order, and terms such as "first" and "second" do not necessarily limit being different.

[0057] It should be noted that in the present invention, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the present invention should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific manner.

[0058] In the present invention, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist.

[0059] As Figure 1 shown, the embodiments of the present invention provide an optical interconnection system on an optical chip, which at least includes: a microring modulation device 10, a polarization combiner 20, and a demultiplexer 30; the output end of the microring modulation device 10 is connected to the input end of the polarization combiner 20; the input end of the demultiplexer 30 is connected to the output end of the polarization combiner 20;

[0060] The microring modulation device 10 is used to modulate signals of TE 0 polarized light and TM 0 polarized light in the light source;

[0061] The polarization combiner 20 is used to combine the TE 0 polarized light and TM 0 polarized light output by the microring modulation device 10 and output the combined light;

[0062] The demultiplexer 30 is used to decompose the combined light into signals corresponding to multiple wavelengths. Specifically, the demultiplexer 30 couples optical signals of different wavelengths into different optical waveguides respectively.

[0063] The demultiplexer 30 may include types such as cascaded ring resonators, arrayed waveguide gratings (WG), or etched diffraction gratings (EDG).

[0064] See Figure 2 , the light source includes optical signals corresponding to a target number of wavelengths. For example, the coherent light source outputs wavelength λ 1-λ i coherent light, each wavelength of signal light includes TE 0 Polarized light and TM 0 polarized light; then the polarized light in the two polarization states contains 2i signal lights in total (see Figure 2 2i data in ), where i is a positive integer greater than 1.

[0065] As described above, the micro-ring modulation device 10 modulates the TE 0 Polarized light and TM 0 After the polarized light is modulated, the polarization multiplexing technology is preliminarily completed. Then the polarization combiner 20 combines the two polarized lights after the signal modulation and transmits them to the demultiplexer 30. The demultiplexer 30 then separates the combined signal according to the number of wavelengths to obtain multiple wavelengths (for example Figure 1 The demultiplexer 30 also independently completes the wavelength division multiplexing technology. Thus, the optical interconnection system on the optical chip in the embodiment of the present invention combines the polarization multiplexing technology with the wavelength division multiplexing technology, which increases the number of multiplexed channels of the optical interconnection system exponentially, and increases the amount of data that can be transmitted per unit time exponentially, greatly improving the data capacity of the optical interconnection system.

[0066] like Figure 1 As shown, the optical interconnection system on the optical chip also includes: a first polarization beam splitter 40 and a second polarization beam splitter 50; the output end of the first polarization beam splitter 40 is connected to the input end of the micro-ring modulation device 10; the input port of the second polarization beam splitter 50 is connected to the output port of the demultiplexer 30;

[0067] The first polarization beam splitter 40 is used to split the light source into TE 0 Polarized light and TM 0 polarized light;

[0068] The second polarization beam splitting device 50 is used to perform polarization beam splitting on the signal corresponding to each wavelength output by the demultiplexer 30 .

[0069] It is understandable that if Figure 1 As shown, the second polarization beam splitting device 50 includes a plurality of polarization beam splitters, each of which performs polarization beam splitting on the signal of the corresponding wavelength output by the demultiplexer 30, and each polarization beam splitted signal is received by each photodetector.

[0070] Among them, the photodetector is used to detect the intensity of the optical signal, convert the optical signal into an electrical signal and demodulate it. After the signal is converted into an electrical signal, it is processed into a digital signal, which usually needs to go through a filter, an analog-to-digital converter, an amplifier and other steps. The digital signal processing part uses existing devices and will not be described in detail.

[0071] Optionally, the photodetector may include a semiconductor photodiode, an APD, a phototransistor, etc.

[0072] It can be understood that, as Figure 1 shown, the microring modulation device 10 includes two microring modulators 100, and each microring modulator 100 modulates polarized light of one mode (either TE 0 polarized light or TM 0 polarized light). For example Figure 1 , microring modulator 1 modulates TE 0 polarized light, and microring modulator 2 modulates TM 0 polarized light. As another example, microring modulator 2 modulates TE 0 polarized light, and microring modulator 1 modulates TM 0 polarized light.

[0073] Referring to Figure 3 , Figure 4 and Figure 5 shown, each microring modulator 100 in the microring modulation device 10 includes at least a plurality of microring series structures; each microring series structure 110 includes a first microring structure 111 and a second microring structure 112 connected in series; the first microring structure 111 is used to perform signal modulation on the signal to be modulated of the corresponding wavelength, and the second microring structure 112 is used to perform phase shift on the modulated signal. It should be noted that the microring structure in this embodiment refers to a circular structure formed by an optical waveguide.

[0074] Specifically, a PN junction 113 is provided on the first microring structure 111; the PN junction 113 is used to load an electrical signal onto the optical signal to complete preliminary signal modulation.

[0075] The first microring structure provided with the PN junction 113 forms a microring resonator, whose function is equivalent to a modulator, loading the electrical signal carrying information (such as audio and video, or Figure 2 the data in

[0076] etc.) onto the optical signal (i.e., the carrier signal) output by the first polarization beam splitting device 40, and by changing parameters such as the amplitude and frequency of the carrier signal, making the carrier signal carry the information of the electrical signal to complete preliminary signal modulation.

[0077] Analysis of technical effects:

[0078] In a first aspect, in the prior art, a micro-ring modulation device for modulating a polarized light signal often uses a waveguide transmission line structure as a phase shifter. The waveguide transmission line structure is not a ring waveguide structure, and the stability of the waveguide transmission line structure is not high enough.

[0079] The phase shifter in this embodiment uses a micro-ring structure (i.e., the second micro-ring structure). The micro-ring structure can effectively confine photons in the waveguide and the ring cavity, reduce the radiation and scattering of the optical signal to the external environment, improve the stability and transmission efficiency of the optical signal during transmission, thereby improving the signal transmission quality. Moreover, due to the special structure of the micro-ring structure itself, it has low transmission loss, can achieve long-distance transmission of optical signals, and effectively improves the optical signal transmission efficiency and system stability.

[0080] In a second aspect, modulators in the prior art often include a Mach-Zehnder modulator (MZM) and an electro-absorption modulator (EAM). In a Mach-Zehnder modulator, it generally consists of two Y-branch waveguides and an interference arm, and electrodes are arranged on the interference arm. However, these above structures have some deficiencies: First, such a complex structure increases the manufacturing difficulty and cost, and has extremely high requirements for process accuracy. Tiny manufacturing errors will affect the modulation performance. Second, due to this complex structure including multiple functional regions and a long waveguide path, the MZM usually occupies a large chip area, which may limit the further improvement of the integration degree in applications such as highly integrated optical communication chips. In an electro-absorption modulator (EAM), it usually consists of an acousto-optic medium, a transducer, an acoustic absorption material, etc. An electrical signal is applied to the transducer to generate ultrasonic waves. The ultrasonic waves propagating in the acousto-optic medium will cause periodic changes in the density of the medium, and then lead to periodic changes in the refractive index, forming an ultrasonic grating. However, these above structures have some deficiencies: First, the modulation performance of the EAM is closely related to the absorption characteristics of the semiconductor material, and has a good modulation effect on optical signals in a specific wavelength range. When the wavelength changes, it may be necessary to redesign or adjust the device parameters, which limits its flexibility in multi-wavelength and wide-spectrum applications. Second, it is difficult for the EAM to achieve as high an extinction ratio as other modulators, that is, the ability to completely turn off the optical signal is limited, which may affect the signal transmission quality and anti-interference ability.

[0081] The PN - junction structure in this embodiment has the following advantages: 1) The structure is simple, formed by the direct contact of P - type and N - type semiconductors. The manufacturing process is relatively easy, without the need for complex waveguide structures or special quantum well material growth processes, reducing the production difficulty and cost; 2) The signal modulation method of the PN - junction is simple and direct, without the need for complex interference or specific absorption effects, easy to understand and control, and convenient for implementing simple optical signal modulation tasks; 3) The PN - junction in this embodiment can effectively modulate optical signals of different wavelengths. In multi - wavelength optical communication and multi - spectral sensing, multiple wavelength signals can be modulated simultaneously without the need for complex designs for different wavelengths.

[0082] Specifically, the specific number of the series - connected micro - ring structures is related to the number of signals in the light source. For example, if the light source contains a target number (e.g., i) of wavelengths of optical signals as described above, then for the micro - ring modulation device, each micro - ring modulator contains 2 times the target number (e.g., 2i) of series - connected micro - ring structures.

[0083] Regarding the specific structural parameters (such as the micro - radius) of the micro - ring structure, the parameters of the micro - ring structure are related to the resonant wavelength. Specifically, the relationship between the resonant wavelength and the micro - ring radius in the first micro - ring structure is:

[0084]

[0085] In formula (1), λ is the resonant wavelength, n eff is the effective refractive index of the first micro - ring structure, R is the micro - ring radius of the first micro - ring structure, and m is a positive integer greater than or equal to 1.

[0086] The round - trip phase shift of the second micro - ring structure is:

[0087] θ = βL (2)

[0088] In formula (2), L = 2πR; β is the propagation constant, and L is the perimeter of the second micro - ring structure.

[0089] In addition, the free spectral range refers to the spectral interval between adjacent two interference orders or resonant peaks in an optical system. Within this spectral range, there will be no overlap of interference fringes or resonant peaks of different orders, and the spectrum has relative "freedom", that is, the signals corresponding to each wavelength can be clearly resolved and distinguished without being confused with the signals of other wavelengths.

[0090] The free spectral range (FSR) of the series - connected micro - ring structure is calculated based on the Vernier effect. Assume that the perimeters of two micro - rings are L 1 and L 2 (L 1 :L2 = m 1 : m 2 ; L 1 = 2πR 1 ; L 2 = 2πR 2 ; m 1 and m 2 are relatively prime integers), when the micro-ring structures are connected in series, the overall free spectral range is extended to:

[0091] FSR expand = m 1 * FSR 1 = m 2 * FSR 2 (3)

[0092] In formula (3), FSR 1 and FSR 2 are the free spectral ranges of the two micro-ring structures.

[0093] As can be seen from the above, the use of the micro-ring series structure can achieve performance improvement and phase adjustment. By connecting two micro-rings in series, the FSR is expanded, the number of supported channels is increased, a box-shaped spectrum is formed, the bandwidth of a single micro-ring modulator is improved, and at the same time, signal modulation and phase control are completed, enabling the support of advanced modulation formats to achieve high-speed information transmission.

[0094] Optionally, the polarization beam splitter is a reverse-designed polarization beam splitter. The reason for choosing the reverse-designed polarization beam splitter is that it has the following effects: 1) Higher polarization extinction ratio: The traditional design method may encounter bottlenecks in pursuing a high polarization extinction ratio, while reverse design can precisely control the propagation characteristics of light in different polarization states through fine optimization of the optical structure, thereby achieving a higher polarization extinction ratio, making the effect of polarization beam splitting more ideal and being able to more effectively separate light with different polarization directions. 2) Broader working bandwidth: Reverse design can flexibly adjust the structure of the polarization beam splitter according to specific application requirements, breaking the problem of limited bandwidth in traditional design and achieving efficient polarization beam splitting function in a wider wavelength range, meeting application scenarios such as multi-wavelength communication and wide-spectrum imaging that require wide-band polarization beam splitting. 3) Reduced insertion loss: Through reverse design, the propagation path and mode matching of light inside the beam splitter can be optimized, reducing the energy loss of light during transmission, lowering the insertion loss, and improving the optical efficiency of the polarization beam splitter to ensure that more light energy is effectively utilized.

[0095] For example Figure 3 , in an optional implementation manner, multiple micro-ring series structures are arranged in an array, that is, a micro-ring modulator is an array of micro-ring series structures. For example, a micro-ring modulator includes 2 rows and i columns of micro-ring series structures.

[0096] See Figure 3 , specifically, each microring modulator 100 further includes a first waveguide 120, a first optical splitter 130, and a first combiner 140.

[0097] See Figure 3 , the first end of the first waveguide 120 is connected to the first optical splitter 130; the second end of the first waveguide 120 is connected to the first combiner 140; the first optical splitter 130 is configured to split TE 0 polarized light or TM 0 polarized light into two signals with equal power; each of the two signals includes modulated signals corresponding to multiple wavelengths (for example Figure 3 there are signals corresponding to i wavelengths in

[0098] See Figure 3 , all the first microring structures 111 in the multiple microring series structures are connected to the first waveguide 120; the first waveguide 120 is configured to introduce the two signals into the multiple microring series structures and transmit the signals after modulation by the multiple microring series structures to the first combiner 140.

[0099] Specifically, the first waveguide 120 introduces the first signal in the two signals into the first row of microring series structures, and the first waveguide 120 introduces the second signal in the two signals into the second row of microring series structures. Whether it is the first row of microring series structures or the second row of microring series structures, in any row of microring series structures, since the microring radii of each first microring structure 111 are different, each first microring structure 111 can be combined with a PN junction 113 to form a microring resonator for selecting an optical signal corresponding to a wavelength and loading a corresponding electrical signal on the optical signal corresponding to the wavelength to complete the preliminary modulation of the signal, and then transmit the signal after preliminary modulation to the second microring structure 112. The second microring structure 112 performs a phase shift on the signal after preliminary modulation, and the signal after phase shift is the signal after final modulation (i.e., the signal after modulation). The signal after modulation then returns to the first waveguide 120 via the microring series structure 110, and the first waveguide 120 transmits the signal after modulation to the first combiner 140 for beam combining processing.

[0100] For example Figure 4 , in a specific embodiment, the microring series structure is used in a QPSK modulator. A 3dB optical splitter splits TE 0 polarized light or TM 0 polarized light into two signals with equal power, one is the I signal and the other is the Q signal. For the signal I i , its corresponding phase shift parameter is For the signal Q i , its corresponding phase shift parameter is Moreover,

[0101] For example Figure 5 , in an alternative embodiment, multiple micro-ring series structures are arranged in an array form, that is, one micro-ring modulator is an array of micro-ring series structures. For example, one micro-ring modulator includes 2 rows and i columns of micro-ring series structures.

[0102] Specifically, each micro-ring modulator further includes a second waveguide 121, a third waveguide 122, a fourth waveguide 123, a second optical splitter 131, and a second beam combiner 141; the multiple micro-ring series structures include a first row of micro-ring series structures and a second row of micro-ring series structures; one end of the second waveguide 121 and one end of the third waveguide 122 are both connected to the second optical splitter 131; all the first micro-ring structures in the first row of micro-ring series structures are connected to the second waveguide 121; the second waveguide 121 is used to introduce the first path of the two paths of signals decomposed by the second optical splitter 131 into the first row of micro-ring series structures; all the first micro-ring structures 111 in the second row of micro-ring series structures are connected to the third waveguide 122; the third waveguide 122 is used to introduce the second path of the two paths of signals decomposed by the second optical splitter 131 into the second row of micro-ring series structures; all the second micro-ring structures 112 in the multiple micro-ring series structures are connected to the fourth waveguide 123; one end of the fourth waveguide 123 is connected to the second beam combiner 141; the fourth waveguide 123 is used to transmit the signal that has completed the final modulation to the second beam combiner 141; the second beam combiner 141 is used for signal combination.

[0103] Specifically, when the second waveguide 121 introduces the first path of the two paths of signals decomposed by the second optical splitter 131 into the first row of micro-ring series structures, each first micro-ring structure 111 in the first row of micro-ring series structures has a different micro-ring radius. Therefore, each first micro-ring structure 111 can be combined with a PN structure to form a micro-ring resonator for selecting an optical signal corresponding to a wavelength and loading a corresponding electrical signal on the optical signal corresponding to the wavelength to complete the preliminary modulation of the signal. Then, the signal that has completed the preliminary modulation is transmitted to the second micro-ring structure 112, and the second micro-ring structure 112 performs phase shift on the preliminarily modulated signal. The signal after phase shift is the signal that has completed the final modulation (that is, the signal after modulation ends). The signal after modulation ends is then transmitted to the fourth waveguide 123, and the fourth waveguide 123 transmits the signal that has completed the final modulation to the second beam combiner 141 for beam combination processing.

[0104] Specifically, when the second waveguide 121 introduces the second of the two signals obtained by splitting the second optical splitter 131 into the second row of cascaded microring structures, each first microring structure 111 in the second row of cascaded microring structures has a different microring radius. Therefore, each first microring structure 111 can be combined with a PN structure to form a microring resonator for selecting an optical signal of a corresponding wavelength and loading a corresponding electrical signal onto the optical signal of the corresponding wavelength to complete the preliminary modulation of the signal. Then, the signal after the preliminary modulation is transmitted to the second microring structure 112, and the second microring structure 112 performs a phase shift on the preliminarily modulated signal. The signal after the phase shift is the signal after the final modulation (i.e., the signal after the modulation ends). The signal after the modulation ends is then transmitted to the fourth waveguide 123, and the fourth waveguide 123 transmits the signal after the final modulation to the second beam combiner 141 for beam combining processing.

[0105] As described above, arranging multiple cascaded microring structures in an array form can reduce the circuit area and improve the utilization rate of the optical chip.

[0106] Optionally, a heater may also be provided on the first microring structure 111 or the second microring structure 112 to stabilize the operating wavelength.

[0107] In another alternative embodiment, referring to Figure 6 , each microring modulator 100 in the microring modulation device includes a plurality of microring combination structures 150, a fifth waveguide 124, a sixth waveguide 125, a seventh waveguide 126, an interlayer coupler 160, and a third beam combiner 142;

[0108] Each microring combination structure 150 includes a third microring structure 151, a fourth microring structure 152, and a fifth microring structure 153; the fourth microring structure 152 is connected to the third microring structure 151; the fifth microring structure 153 is connected to the third microring structure 151 and the fifth microring structure 153 is located above the third microring structure 151; both the third microring structure 151 and the fourth microring structure 152 are located between the fifth waveguide 124 and the sixth waveguide 125; the third microring structure 151 is connected to the fifth waveguide 124; the fifth waveguide 124 is used to introduce TE 0 polarized light or TM 0 polarized light into the third microring structure 151; the third microring structure 151 is used to load an electrical signal onto TE 0 polarized light or TM 0The TE polarized light is used to complete the preliminary signal modulation; the fourth micro-ring structure 152 is connected to the sixth waveguide 125, and the fourth micro-ring structure 152 is used to perform phase shift on the preliminarily modulated signal; the fifth micro-ring structure 153 is connected to the seventh waveguide 126, and the fifth micro-ring structure 153 is used to perform phase shift on the modulated signal; the end of the seventh waveguide 126 is connected to the third beam combiner 142 through the interlayer coupler 160; the end of the sixth waveguide 125 is connected to the third beam combiner 142.

[0109] Working principle: For example, the fifth waveguide 124 introduces the TE 0 polarized light into all the third micro-ring structures 151. Each third micro-ring structure 151 can select the TE 0 polarized light corresponding to a wavelength as the carrier signal due to different micro-ring radii. Then, the electrical signal carrying information is loaded on the carrier signal to complete the preliminary signal modulation. At the same time, the signal after completing the preliminary signal modulation is output to the fourth micro-ring structure 152 and the fifth micro-ring structure 153. The fourth micro-ring structure 152 performs phase shift of the first preset phase and transmits it to the third beam combiner 142 through the sixth waveguide 125. The fifth micro-ring structure 153 performs phase shift of the second preset phase and transmits it to the interlayer coupler 160 through the seventh waveguide 126, and then is transmitted to the third beam combiner 142 by the interlayer coupler 160.

[0110] Compare the Figure 6 micro-ring modulator exemplified in Figure 5 with the micro-ring modulator exemplified in Figure 6 . It can be found that the micro-ring modulator in Figure 5 uses 2 chip layers to complete the modulation and phase shift of 2-way signals. In this way, Figure 6 the micro-ring modulation in is coupled in the vertical direction and is relatively independent of other optical signal transmission paths in the horizontal direction. Therefore, it can effectively reduce the crosstalk between different optical channels, increase the stability of signal processing, and improve the signal quality. This structure is compatible with the existing CMOS process. The three-dimensional vertical micro-ring structure breaks through the limitations of the traditional two-dimensional planar waveguide structure and can achieve a higher device integration degree within a smaller planar size.

[0111] In an alternative embodiment, in combination with Figure 1 and Figure 7The signal demodulation is described as follows. The received optical signal and the local oscillator are both divided into two beams of light. One beam of the received optical signal and the local oscillator signal are coupled through a 3dB coupler and then received by the corresponding photodetector. The other beam of the received optical signal passes through a phase shift of π / 2 and is coupled with the local oscillator signal through another 3dB coupler and then received by the corresponding photodetector. Only one local oscillator is needed to provide a reference signal for all branches. Then the received signal and the local oscillator interfere, and then the in-phase part and the quadrature-phase part are separated. Finally, the two beams of signals are subtracted. Based on the symbol mapping mechanism of QPSK (Quadrature Phase Shift Keying), the extracted in-phase and quadrature-phase components are converted into the original digital signal, and then the original binary data is restored.

[0112] Although the present invention has been described in connection with various embodiments, it will be understood by those skilled in the art that other variations of the disclosed embodiments can be understood and effected while practicing the claimed invention, by studying the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions recited in several claims. Certain measures are recited in mutually different dependent claims, but this does not indicate that these measures cannot be combined to advantage.

[0113] Although the present invention has been described in connection with specific features and their embodiments, it will be apparent that various modifications and combinations can be made without departing from the spirit and scope of the invention. Accordingly, the specification and drawings are merely exemplary illustrations of the invention defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. An optical interconnection system on an optical chip, characterized in that: At least: Micro-ring modulation devices, polarization combiners and demultiplexers; The output end of the micro-ring modulation device is connected to the input end of the polarization combiner; the input end of the demultiplexer is connected to the output end of the polarization combiner; The micro-ring modulation device is used to perform signal modulation on TE0 polarized light and TM0 polarized light in the light source; The polarization combiner is used to combine the TE0 polarized light and the TM0 polarized light output by the micro-ring modulation device and output the combined light; The demultiplexer is used to decompose the combined light beam into signals corresponding to multiple wavelengths.

2. The optical interconnect system on an optical chip according to claim 1, characterized in that: Also includes: a first polarization beam splitting device and a second polarization beam splitting device; The output end of the first polarization beam splitter is connected to the input end of the micro-ring modulation device; the input port of the second polarization beam splitter is connected to the output port of the demultiplexer; The first polarization beam splitter is used to decompose the light source into the TE0 polarized light and the TM0 polarized light; The second polarization beam splitting device is used to perform polarization beam splitting on the signal corresponding to each wavelength output by the demultiplexer.

3. The optical interconnection system on an optical chip according to claim 1, characterized in that: in, Each micro-ring modulator in the micro-ring modulation device comprises at least a plurality of micro-ring series structures; Each micro-ring series structure includes a first micro-ring structure and a second micro-ring structure connected in series; The first micro-ring structure is used to modulate the signal to be modulated of the corresponding wavelength, and the second micro-ring structure is used to shift the phase of the modulated signal.

4. The optical interconnection system on an optical chip according to claim 3, characterized in that: A PN junction is arranged on the first micro-ring structure; the PN junction is used to load an electrical signal onto an optical signal to complete preliminary signal modulation.

5. The optical interconnection system on an optical chip according to claim 4, characterized in that: The multiple micro-ring series structures are arranged in an array.

6. The optical interconnection system on an optical chip according to claim 5, characterized in that: Each micro-ring modulator also includes a first waveguide, a first optical splitter, and a first beam combiner; The first end of the first waveguide is connected to the first optical splitter; the second end of the first waveguide is connected to the first beam combiner; the first optical splitter is used to decompose the TE0 polarized light or the TM0 polarized light into two signals with equal power; each of the two signals includes signals to be modulated corresponding to multiple wavelengths; All the first micro-ring structures in the multiple micro-ring series structures are connected to the first waveguide; the first waveguide is used to introduce the two signals into the multiple micro-ring series structures and transmit the signals after the modulation of the multiple micro-ring series structures to the first combiner.

7. The optical interconnection system on an optical chip according to claim 5, characterized in that: Each micro-ring modulator further includes a second waveguide, a third waveguide, a fourth waveguide, a second optical splitter, and a second combiner; the plurality of micro-ring series structures include a first row of micro-ring series structures and a second row of micro-ring series structures; One end of the second waveguide and one end of the third waveguide are both connected to the second optical splitter; All the first micro-ring structures in the first row of micro-ring series structures are connected to the second waveguide; the second waveguide is used to introduce the first signal of the two signals decomposed by the second optical splitter into the first row of micro-ring series structures; All the first micro-ring structures in the second row of micro-ring series structures are connected to the third waveguide; the third waveguide is used to introduce the second signal of the two signals decomposed by the second optical splitter into the second row of micro-ring series structures; All the second micro-ring structures in the plurality of micro-ring series structures are connected to the fourth waveguide; One end of the fourth waveguide is connected to the second beam combiner; the fourth waveguide is used to transmit the signal that has completed the final modulation to the second beam combiner; The second beam combiner is used to combine the signals that have completed the final modulation.

8. The optical interconnection system on an optical chip according to claim 4, characterized in that: Each micro-ring modulator in the micro-ring modulation device comprises a plurality of micro-ring combination structures, a fifth waveguide, a sixth waveguide, a seventh waveguide, an interlayer coupler and a third combiner; Each microring combination structure includes a third microring structure, a fourth microring structure and a fifth microring structure; the fourth microring structure is connected to the third microring structure; the fifth microring structure is connected to the third microring structure and the fifth microring structure is located above the third microring structure; The third micro-ring structure and the fourth micro-ring structure are both located between the fifth waveguide and the sixth waveguide; The third microring structure is connected to the fifth waveguide; the fifth waveguide is used to introduce the TE0 polarized light or the TM0 polarized light into the third microring structure; the third microring structure is used to load the electrical signal onto the TE0 polarized light or the TM0 polarized light to complete preliminary signal modulation; The fourth micro-ring structure is connected to the sixth waveguide, and the fourth micro-ring structure is used to perform phase shifting on the preliminarily modulated signal; The fifth microring structure is connected to the seventh waveguide, and the fifth microring structure is used to perform phase shifting on the modulated signal; The end of the seventh waveguide is connected to the third combiner through the interlayer coupler; An end of the sixth waveguide is connected to the third combiner.

9. The optical interconnection system on an optical chip according to claim 3, characterized in that: The relationship between the resonant wavelength and the microring radius in the first microring structure is: where λ is the resonant wavelength, n eff is the effective refractive index, R is the microring radius of the first microring structure, and m is a positive integer greater than or equal to 1; The phase shift of the second micro-ring structure is: θ = βL; in, L=2πR; β is a propagation constant, and L is a length of the second micro-ring structure.

10. An optical chip, characterized in that: The optical interconnection system on an optical chip comprises the optical interconnection system on an optical chip as described in any one of claims 1 to 9.

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