Integrated multi-channel delay compensation and coupling method and system for optical computing chips

Abstract

The application provides a kind of integrated multi-channel delay compensation and coupling method and system of optical computing chip, and the relative delay measurement of input channel and reference channel of optical computing chip is carried out;The actual position of the port of optical computing chip and the geometric dimension information are obtained, and the photoresist refractive index of each channel is combined with the relative delay value and the photonic lead structure is designed;The optical computing chip and the optical fiber array are cleaned and fixed on the transparent substrate, then the photoresist is dropped to the interconnection area;The photonic lead structure is formed by using femtosecond laser to expose point by point inside the photonic lead design structure;Remove the unexposed photoresist, and drop the low refractive index matching liquid matched with the used photoresist refractive index to form the waveguide cladding, complete the integrated multi-channel delay compensation and coupling of optical computing chip.The application uses femtosecond laser to manufacture photonic lead structure, realizes highly compact, delay compensation and integrated multi-channel coupling interconnection.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic chip function control and optical coupling technology, specifically to an integrated multi-channel delay compensation and coupling method and system for an optical computing chip implemented using photonic leads. Background Technology

[0002] Optical neural network computing has the potential to overcome bandwidth bottlenecks and achieve ultra-high computing speeds. Furthermore, optical neural network computing operates in the analog domain, effectively reducing the energy and time consumption associated with memory access. By utilizing the physical mechanisms of light diffraction and interference, high-speed and parallel optical neural network computations can be achieved. However, optical computing chips have high requirements for latency uniformity across multiple channels. Fabrication deviations in optical computing chips and limitations of traditional end-face and grating coupling methods cannot guarantee the uniformity of latency in multi-channel systems.

[0003] In optical computing chips, different channels carry different data, and each functional module requires data from different channels to function properly according to a specific timing sequence. If the delays of different channels are inconsistent, the data from different channels will arrive at the target module at different times, leading to erroneous operations of the functional modules. To address the delay consistency problem in optical computing chips, external delay lines are often used, but this method has low integration density and presents challenges in large-scale multi-path compensation.

[0004] Photonic wire bonding (PWB) utilizes the nonlinear effect of femtosecond laser pulses to induce a two-photon polymerization effect by focusing the beam onto photosensitive resin, forming a three-dimensional free-form polymer waveguide between interconnecting devices. This technology has the potential to achieve optical coupling between optical chips and efficient on-chip delay compensation. Currently, PWB has been used to achieve hybrid packaging of multi-channel chips in optical transceivers in optical communication systems (see: M. Blaicher et al., “Hybrid multi-chip assembly of optical communication engines by in situ 3D nano-lithography,” Light Sci. Appl., vol. 9, no. 1, pp. 1–11, Dec. 2020). However, this work only achieves low-loss coupling between different ports using photonic wires, but does not realize multi-channel delay compensation. By fabricating three-dimensional polymer waveguides of different physical lengths between optical computing chips and fiber arrays using PWB to compensate for delays between multiple channels, multi-channel delay-compensated coupling interconnection can be achieved. However, no descriptions or reports of similar techniques for compensating multi-channel delay using photonic leads have been found, nor have similar materials been collected domestically or internationally. Therefore, how to meet the requirements of multi-channel delay compensation while achieving low-loss optical signal transmission is a problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the aforementioned shortcomings in the prior art, this invention provides an integrated multi-channel delay compensation and coupling method and system for optical computing chips.

[0006] According to one aspect of the present invention, an integrated multi-channel delay compensation and coupling method for an optical computing chip is provided, comprising:

[0007] The relative delay values ​​of the input and reference channels of the optical computing chip are measured in multiple channels.

[0008] The actual location and geometric dimensions of the optical computing chip's ports are obtained, and the photonic lead structure is designed by combining the relative delay values ​​of each channel and the photoresist refractive index of the photonic lead, thus obtaining the photonic lead design structure.

[0009] The optical computing chip and fiber array are cleaned and fixed on a transparent substrate, and then photoresist is applied to the interconnect area.

[0010] The photonic lead structure is formed by point-by-point exposure along the interior of the aforementioned photonic lead design structure;

[0011] Remove the unexposed photoresist and drop-coat a low refractive index matching liquid that matches the refractive index of the photoresist to form a waveguide cladding, thus completing the integrated multi-channel delay compensation and coupling of the optical computing chip.

[0012] Preferably, the measurement of the multi-channel relative delay values ​​of the input and reference channels of the optical computing chip includes:

[0013] Using an optical alignment platform, one end of the input channel and reference channel of the optical computing chip is connected to a broadband light source via optical fiber, and the other end of the input channel and reference channel of the optical computing chip is connected to a photodetector via optical fiber. The photodetector converts the optical signal into an electrical signal and transmits the electrical signal to the input channel of the oscilloscope. The relative delay value of each channel is then measured by the oscilloscope.

[0014] Preferably, the relative delay values ​​of each channel measured by the oscilloscope include:

[0015] Adjust the displacement of the fiber optic clamp to obtain the best optical coupling effect;

[0016] Analyze the signals obtained from the oscilloscope to obtain the amplitude response of each channel;

[0017] Based on the amplitude response of each channel, the phase response of each channel is calculated using the KK relationship, and then the phase information in the frequency domain is converted into the phase information in the time domain through inverse Fourier transform, from which the relative delay value of each channel is obtained.

[0018] Preferably, the step of acquiring the actual port location and geometric dimensions of the optical computing chip, and combining the relative delay values ​​of each channel and the photoresist refractive index of the photonic lead, designs the photonic lead structure to obtain the photonic lead design structure, including:

[0019] The actual position and orientation angle of the end coupler port and fiber array port of the optical computing chip are detected using the imaging system of the femtosecond laser platform;

[0020] Based on the port size, actual coordinates, direction vector, and relative delay information of each channel of the end-face coupler and fiber array, a segmented photonic lead structure is designed, resulting in the photonic lead design structure.

[0021] Preferably, the photonic lead design structure includes: a platform-transition straight waveguide, a mode shape conversion waveguide, a curved waveguide, and a conical transition straight waveguide; wherein:

[0022] The platform transition straight waveguide is a cubic waveguide structure that gradually thickens. The large-diameter rectangular end of the platform transition straight waveguide completely covers the light-emitting end face of the end face coupler, and the small-diameter rectangular end of the platform transition straight waveguide is connected to the rectangular port of the mode shape conversion waveguide.

[0023] The mode shape conversion waveguide is a cylindrical waveguide structure that transitions from rectangular to circular, and the circular port of the mode shape conversion waveguide is connected to a curved waveguide.

[0024] The curved waveguide is a curved cylindrical waveguide structure with a circular cross-section and fixed dimensions. The other end of the curved waveguide is connected to the small-diameter port of the conical transition straight waveguide. By designing the trajectory of the curved waveguide, delay compensation for each channel can be achieved.

[0025] The conical transition straight waveguide is a tapered waveguide structure that gradually thickens, and its large-diameter port is connected to an optical fiber array.

[0026] Preferably, the radius of the circular cross-section of the curved waveguide should meet the requirements for single-mode optical signal transmission.

[0027] Preferably, designing the trajectory of the curved waveguide includes:

[0028] Based on the relative delay values ​​T1 to T2 of each channel n Let the first channel be the channel with the longest delay, and its relative delay value be T1. Then the relative delay difference between the remaining channels and the first channel is T1-T2 to T1-T. n Using wavelength, photoresist refractive index, and relative delay difference information, the physical length that the remaining channels need to increase relative to the first channel is calculated to be L2 to L. n ;

[0029] The actual coordinates r of the end face coupler of the first channel and the end face of the fiber array 10 and r 11 and unit direction vector and Adjust 'a' using the optimization method x0 ~a z5 The value of the loss To minimize and ultimately obtain the curved waveguide trajectory of the first channel. The length of the curved waveguide in the first channel is then... in, and Let x1(t), y1(t), and z1(t) represent the first derivatives of x1(t), y1(t), and z1(t) with respect to the parameter t, respectively. We then obtain:

[0030]

[0031]

[0032]

[0033] x1(t)=ax0 t 5 +a x1 t 4 +a x2 t 3 +a x3 t 2 +a x4 t+a x5

[0034] y1(t)=a y0 t 5 +a y1 t 4 +a y2 t 3 +a y3 t 2 +a y4 t+a y5

[0035] z1(t)=a z0 t 5 +a z1 t 4 +a z2 t 3 +a z3 t 2 +a z4 t+a z5

[0036]

[0037]

[0038]

[0039]

[0040] in, Let α represent the total loss of the curved waveguide in the first channel, α represent the material absorption and surface scattering coefficients of the curved waveguide, κ1(t) represent the reciprocal of the radius of curvature of the curved waveguide in the first channel, and t represent the parameters of the trajectory equation and 0. <t<1, This represents the direction vector along the curved waveguide trajectory of the first channel. and They represent The first and second derivatives with respect to the parameter t;

[0041] Based on the actual coordinates of the end face couplers and fiber array end faces of the remaining channels. and and unit direction vector and The lengths of the curved waveguides in the newly added remaining channels are respectively Under the constraints, similarly, optimization methods can be used to make... To reach the minimum, the trajectory equation of the remaining channel is: Where the number of channels i = 1…n.

[0042] Preferably, the step of cleaning and fixing the optical computing chip and fiber array onto a transparent optical substrate, and then applying photoresist to the interconnect area, includes:

[0043] The optical computing chip, fiber array, and transparent optical substrate were cleaned using organic solvents, and the optical computing chip and fiber array were fixed on the transparent optical substrate.

[0044] Heating equipment is used to remove residual organic solvents and moisture;

[0045] Photoresist is deposited between the optical computing chip and the fiber array.

[0046] Preferably, the transparent optical substrate is a stepped glass slide or a sapphire film.

[0047] Preferably, the step of forming the photonic lead structure by point-by-point exposure along the interior of the photonic lead design structure includes:

[0048] The coated sample is placed on the displacement stage of the femtosecond laser platform;

[0049] Based on the aforementioned photonic lead design structure, the femtosecond laser focus is controlled to expose the photoresist layer point by point.

[0050] Preferably, the step of controlling the femtosecond laser focus to expose the photoresist layer point by point according to the photonic lead design structure includes:

[0051] The photonic lead design structure is divided into n sections along the beam propagation direction.

[0052] The outer contour trajectory of each section is scaled down proportionally to form a concentric structure with the same center point;

[0053] Divide all the contours of each concentric structure into m points;

[0054] By controlling the femtosecond laser focus and moving it to one of the points, the process of turning on the femtosecond laser exposure, turning off the femtosecond laser, and moving to the next point is executed, so that the femtosecond laser is exposed only at that point, resulting in a polymer dot structure.

[0055] By performing the above process, the concentric structure is exposed point by point in the photoresist from the inside out to obtain a polymer surface structure; the polymer surface structures are stacked to form a three-dimensional polymer body structure to obtain a photonic lead structure.

[0056] Preferably, the method further includes:

[0057] Deposit and position metal markers on the optical computing chip; wherein:

[0058] The mark is either rectangular or triangular in shape;

[0059] The markings are located on both arms of the end coupler and are symmetrical about their axis.

[0060] The number of markers depends on the length of the end face coupler.

[0061] According to another aspect of the present invention, an integrated multi-channel delay compensation and coupling system for an optical computing chip is provided, comprising:

[0062] A multi-channel delay measurement module is used to measure the relative delay between the input and reference channels of an optical computing chip.

[0063] The photonic lead structure design module is used to obtain the actual port location and geometric dimension information of the optical computing chip, and combine the relative delay value of each channel and the photoresist refractive index of the photonic lead to design the photonic lead structure and obtain the photonic lead design structure.

[0064] The photoresist deposition module is used to clean and fix the optical computing chip and fiber array on a transparent substrate, and then use photoresist to drop and coat the interconnect area.

[0065] A photonic lead exposure module, which is used to expose point by point along the interior of the photonic lead design structure to form a photonic lead structure;

[0066] The photonic lead development module is used to remove unexposed photoresist and drop-coat a low refractive index matching liquid that matches the refractive index of the photoresist to form a waveguide cladding, thereby completing the integrated multi-channel delay compensation and coupling function of the optical computing chip.

[0067] Preferably, the system further includes:

[0068] The marking deposition module is used to deposit positioning metal markers on the optical computing chip.

[0069] By adopting the above technical solution, the present invention has at least one of the following beneficial effects compared with the prior art:

[0070] The integrated multi-channel delay compensation and coupling method and system for optical computing chips provided by this invention achieves compact multi-channel delay compensation by processing photonic lead structures of different physical lengths between the fiber array and the optical computing chip, and by designing the trajectory of the photonic leads, thus saving the area overhead of the compensation part.

[0071] The integrated multi-channel delay compensation and coupling method and system for optical computing chips provided by this invention utilizes the two-photon aggregation effect of femtosecond lasers to fabricate photonic lead structures, achieving highly compact, low-transmission-loss delay compensation and coupling integrated multi-channel inter-chip interconnection, supporting the realization of high-accuracy optical computing operations. Attached Figure Description

[0072] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0073] Figure 1 This is a flowchart illustrating the integrated multi-channel delay compensation and coupling method for an optical computing chip in a preferred embodiment of the present invention.

[0074] Figure 2 This is a schematic diagram of the multi-channel delay measurement steps in a preferred embodiment of the present invention.

[0075] Figure 3 This is a schematic diagram of the segmented structure design of the photon lead in a preferred embodiment of the present invention.

[0076] Figure 4 This is a schematic diagram of the photoresist deposition step in a preferred embodiment of the present invention.

[0077] Figure 5 This is a schematic diagram of a photonic lead divided into several sections along the light transmission direction in a preferred embodiment of the present invention.

[0078] Figure 6 This is a schematic diagram of femtosecond laser point-by-point exposure of a single cross section in a preferred embodiment of the present invention.

[0079] Figure 7 This is a schematic diagram of waveguide cladding formed by drop-coating a low-refractive-index matching liquid in a preferred embodiment of the present invention.

[0080] Figure 8 This is a schematic diagram of the components of an integrated multi-channel delay compensation and coupling system for an optical computing chip in a preferred embodiment of the present invention. Detailed Implementation

[0081] The embodiments of the present invention are described in detail below: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0082] One embodiment of the present invention provides an integrated multi-channel delay compensation and coupling method for optical computing chips. The method utilizes femtosecond lasers to fabricate a three-dimensional free-form polymer waveguide in situ between the end-face coupler and the fiber array of the optical computing chip. The transition waveguide structure completes the transformation from a circular waveguide cross-section to a rectangular waveguide cross-section. By designing a curved waveguide trajectory, the relative delay difference of the multi-channel optical computing chip is compensated and low transmission loss is achieved. By optimizing the scanning path of the laser focus to traverse the designed photonic lead structure, a highly compact photonic lead structure integrating delay compensation and coupling is realized.

[0083] Specifically, such as Figure 1 As shown, this embodiment provides an integrated multi-channel delay compensation and coupling method for optical computing chips, which may include the following operations:

[0084] S1, measures the relative delay values ​​of the input and reference channels of the optical computing chip.

[0085] S2, obtain the actual port location and geometric dimension information of the optical computing chip, and combine the relative delay value of each channel and the photoresist refractive index of the photonic lead to design the photonic lead structure and obtain the photonic lead design structure.

[0086] S3, the optical computing chip and fiber array are cleaned and fixed on a transparent substrate, and then photoresist is applied to the interconnect area;

[0087] S4, the photon lead structure is formed by exposing the internal structure point by point along the photon lead design;

[0088] S5 removes the unexposed photoresist and drops a low-refractive-index matching liquid that matches the refractive index of the photoresist to form a waveguide cladding, thus completing the integrated multi-channel delay compensation and coupling of the optical computing chip.

[0089] The technical solution provided by the above embodiments of the present invention will be further described in detail below with reference to a preferred embodiment.

[0090] S100, multi-channel delay measurement: Through an optical alignment platform, one end of the input channel and reference channel of the optical computing chip is connected to a broadband light source via optical fiber, and the other end is connected to a photodetector via optical fiber. The photodetector converts the optical signal into an electrical signal and transmits the electrical signal to the input channel of the oscilloscope. The relative delay value of each input channel is then measured by the oscilloscope.

[0091] In a preferred embodiment of S100, the measurement of the relative delay values ​​of the multiple channels further includes the following operations:

[0092] S101 places the optical computing chip on the optical substrate of the optical coupling test platform, connects one end of the channel under test and the reference channel to a broadband light source through optical fiber, and connects the other end of the channel under test and the reference channel to a photodetector through optical fiber. The photodetector converts the optical signal into an electrical signal, and then inputs the electrical signal to an oscilloscope to capture and measure the received signal.

[0093] S102 achieves optimal optical coupling by adjusting the displacement control system of the fiber optic clamp. By analyzing the signal obtained on the oscilloscope, the amplitude response of each channel can be obtained.

[0094] S103. Based on the amplitude response of each channel, the phase response of each channel is calculated using the Kramers-Kronig relationship. Then, the phase information in the frequency domain is converted into phase information in the time domain through inverse Fourier transform. The relative delay values ​​T1 to T2 of each channel are obtained from the phase information in the time domain. n .

[0095] S200, Photonic Lead Structure Design: By utilizing the imaging system of the femtosecond laser platform to obtain information such as the actual position and geometric dimensions of the port, and combining information such as the relative delay values ​​of each channel and the refractive index of the photoresist of the photonic lead, the photonic lead structure is designed.

[0096] In a preferred embodiment of S200, the photonic lead structure design further includes the following operations:

[0097] S201 uses the imaging system of the femtosecond laser platform to detect the actual position and orientation angle of the end coupler port and fiber array port of the optical computing chip;

[0098] S202, based on the port size, actual coordinates, direction vector, and relative delay value of each channel of the end-face coupler and fiber array, a segmented photonic lead structure is designed to compensate for and couple the fiber array and end-face coupler to ensure consistency of loss and delay.

[0099] In S202, an imaging system can be used to directly observe and obtain information such as the actual coordinates and direction vector of the port. Then, a photonic lead structure for compensating for and coupling the fiber array and the end face coupler can be designed to ensure that multi-channel delay is compensated while achieving low transmission loss.

[0100] In a preferred embodiment of S202, the segmented photonic lead structure comprises a platform-transition straight waveguide, a mode shape conversion waveguide, a curved waveguide, and a conical-transition straight waveguide. Further:

[0101] The platform-transition straight waveguide is a cubic structure that tapers from thin to thick; the mode shape conversion waveguide is a cylindrical structure that transitions from rectangular to circular; the curved waveguide is a curved cylindrical waveguide with a circular cross-section and fixed dimensions; and the conical transition straight waveguide is a conical structure that tapers from thin to thick. The large-diameter rectangular end of the platform-transition straight waveguide completely covers the output end face of the end-face coupler, while the small-diameter rectangular port of the platform-transition straight waveguide connects to the rectangular port of the mode shape conversion waveguide. The circular port of the mode shape conversion waveguide connects to the curved waveguide, while the other end of the curved waveguide connects to the small-diameter port of the conical transition straight waveguide. Finally, the large-diameter circular port of the conical transition straight waveguide connects to the fiber array.

[0102] In a preferred embodiment of S202, the design of the curved waveguide further includes the following operations:

[0103] First, based on the relative delay values ​​T1 to T of each channel... n Let the first channel be the channel with the longest delay, and its relative delay value be T1. Then the relative delay difference between the remaining channels and the first channel is T1-T2 to T1-T. n Using wavelength, photoresist refractive index, and relative delay difference information, the physical length that the remaining channels need to increase relative to the first channel is calculated to be L2 to L. n ;

[0104] Next, the actual coordinates r of the end face of the fiber array are determined through the end face coupler of the first channel. 10 and r 11 and unit direction vector and Adjust 'a' using the optimization method x0 ~a z5 The value of the loss To minimize and ultimately obtain the curved waveguide trajectory of the first channel. The length of the curved waveguide in the first channel is then... in and Let x1(t), y1(t), and z1(t) represent the first derivatives of x1(t), y1(t), and z1(t) with respect to parameter t, respectively.

[0105]

[0106]

[0107]

[0108] x1(t)=a x0 t 5 +a x1 t 4 +a x2 t3 +a x3 t 2 +a x4 t+a x5

[0109] y1(t)=a y0 t 5 +a y1 t 4 +a y2 t 3 +a y3 t 2 +a y4 t+a y5

[0110] z1(t)=a z0 t 5 +a z1 t 4 +a z2 t 3 +a z3 t 2 +a z4 t+a z5

[0111]

[0112]

[0113]

[0114]

[0115] in, Let α represent the total loss of the curved waveguide in the first channel, α represent the material absorption and surface scattering coefficients of the curved waveguide, κ1(t) represent the reciprocal of the radius of curvature of the curved waveguide in the first channel, and t represent the parameters of the trajectory equation and 0. <t<1, This represents the direction vector along the curved waveguide trajectory of the first channel. and They represent The first and second derivatives with respect to the parameter t;

[0116] Finally, based on the actual coordinates of the end-face couplers of the remaining channels and the end-faces of the fiber array... and and unit direction vector and The lengths of the curved waveguides in the newly added remaining channels are respectively Under the constraints, similarly, optimization methods can be used to make... To reach the minimum, the trajectory equation of the remaining channel is: Where the number of channels i = 1…n. In a preferred embodiment of S202, the curved waveguide has a circular cross-section, and the radius should meet the requirements of single-mode optical signal transmission. By carefully designing the trajectory of the curved waveguide, multi-channel delay can be compensated, while achieving low transmission loss.

[0117] S300, photoresist deposition: The optical computing chip and fiber array are cleaned and fixed on a transparent substrate. Then, photoresist is dropped onto the interconnect area and finally placed on a heating device to complete the photoresist drying.

[0118] In a preferred embodiment of S300, photoresist deposition further includes the following operations:

[0119] S301 uses organic solvents such as acetone and isopropanol to clean the optical computing chip, fiber array and transparent optical substrate, and fixes the optical computing chip and fiber array on the transparent optical substrate to ensure that the height of the output port is basically the same.

[0120] S302 uses heating equipment such as ovens or hot plates to remove residual organic solvents and moisture;

[0121] S303 deposits photoresist between an optical computing chip and a fiber array.

[0122] In a preferred embodiment of S301, the transparent optical substrate, which may be made of glass slide, sapphire film, etc., can be designed in a stepped shape to compensate for the height difference between the fiber array and the optical computing chip, avoid excessive alignment offset and increased coupling loss caused by angular offset, and achieve efficient optical interconnection.

[0123] S400, photonic lead exposure: controlling the femtosecond laser focus to expose the photonic lead structure point by point along the designed interior of the photonic lead structure to form the photonic lead structure.

[0124] In a preferred embodiment of S400, photon wire exposure further includes the following operations:

[0125] S401, place the coated sample on the displacement stage of the femtosecond laser platform;

[0126] S402 controls the femtosecond laser focus to expose the photoresist layer point by point according to the designed photonic lead structure.

[0127] In a preferred embodiment of S402, the method for controlling the femtosecond laser focus to expose the photoresist layer point by point includes:

[0128] The designed photonic lead structure is divided into n sections along the beam propagation direction, and each section is exposed by controlling the femtosecond laser to form a three-dimensional polymer structure.

[0129] Furthermore, methods for forming three-dimensional polymer structures also include:

[0130] S4021, the outer contour trajectory of each cross section is scaled down proportionally to form a concentric structure with the same center point; wherein each contour trajectory shares a center with other trajectories and the size gradually decreases. For example, for a circular cross section, it can be divided into a concentric circle structure.

[0131] S4022 divides all the contours of each concentric structure into m points, with the point spacing depending on the size of the laser focus;

[0132] S4023, by controlling the laser focus to expose concentric structures point by point in the photoresist from the inside out, can form a three-dimensional polymer structure.

[0133] In a preferred embodiment of S4023, forming a three-dimensional polymer body structure further includes the following operations:

[0134] S40231, the laser focus is moved to this point - femtosecond laser exposure is turned on - femtosecond laser is turned off - move to the next point, so the femtosecond laser only exposes at this point to form a polymer dot structure;

[0135] S40232, polymer surface structure is formed by stacking polymer dot structures inside the cross section;

[0136] S40233 is a three-dimensional polymer body structure formed by stacking polymer surface structures.

[0137] S500, photonic wire development: Unexposed photoresist is removed by developing solution, and low refractive index matching liquid is dropped on to form waveguide cladding.

[0138] In a preferred embodiment of S500, photon wire development further includes the following operations:

[0139] S501 removes unexposed photoresist through a development process, thereby forming a photonic lead structure;

[0140] S502, a low-refractive-index matching liquid is drop-coated onto the photonic lead structure to form a waveguide cladding. In a specific application example, the low-refractive-index matching liquid can be a chemical solution known in the art, Cargille code 3421.

[0141] In a preferred embodiment of the present invention, the above method further includes:

[0142] In the S600 manufacturing process, positioning metal markers are deposited on the optical computing chip to locate the chip structure. The markers can be rectangular or triangular in shape, etc. The markers are located on both arms of the end coupler and are symmetrical about their axis. The number of markers can be two or four, depending on the length of the end coupler.

[0143] The integrated multi-channel delay compensation and coupling method for optical computing chips provided in the above embodiments of the present invention achieves highly compact, integrated delay compensation and coupling multi-channel inter-chip interconnection by using the two-photon polymerization effect of femtosecond lasers to fabricate photonic lead structures through multi-channel delay measurement, photonic lead structure design, photoresist deposition, photonic lead exposure and photonic lead development.

[0144] The technical solutions provided by the above embodiments of the present invention will be described in detail below with reference to the accompanying drawings and specific application examples. It should be noted that the following description provides detailed implementation methods and structures, but the protection scope of the present invention is not limited to the following embodiments.

[0145] like Figure 1 and Figure 2 As shown, the integrated multi-channel delay compensation and coupling method for optical computing chips implemented in this specific application example includes the following five steps:

[0146] Step 1: Multi-channel relative delay measurement: First, place the optical computing chip on the optical substrate of the optical coupling test platform. Connect one end of the channel under test and the reference channel to a broadband light source via optical fiber. Then connect the other end of the channel under test and the reference channel to a photodetector via optical fiber. The photodetector converts the optical signal into an electrical signal, which is then transmitted to the input port of the oscilloscope to capture and measure the received signal. Next, by adjusting the displacement control system of the fiber optic clamp, the optimal optical coupling effect is achieved, ensuring that the optical signal can be effectively coupled from the broadband light source into the optical computing chip and accurately detected and received by the photodetector and the oscilloscope. By analyzing the signal obtained on the oscilloscope, the amplitude response of each channel can be obtained. Finally, the phase response of each channel is calculated using the Kramers-Kronig relationship, where the Kramers-Kronig relationship is used to obtain the phase response from the amplitude response. The phase information in the frequency domain is converted into the phase information in the time domain through inverse Fourier transform, from which the relative delay values ​​T1 to T2 of each channel are obtained. n .

[0147] Step 2: Photonic Lead Structure Design: First, the actual positions of the end-face coupler 303 port of the optical computing chip 101 and the port of the fiber array 301 are detected using the imaging system of the femtosecond laser platform. Then, based on the port dimensions, actual coordinates, direction vectors, and relative delay values ​​of each channel of the end-face coupler 303 and the fiber array 301, a segmented photonic lead structure is designed. This structure consists of a platform transition straight waveguide 201, a mode shape conversion waveguide 202, a curved waveguide 203, and a conical transition straight waveguide 204. Specifically, the platform transition straight waveguide 201 is a cubic structure that gradually thickens; the mode shape conversion waveguide 202 is a cylindrical transition structure that transitions from rectangular to circular; the curved waveguide 203 is a curved cylindrical waveguide with a circular cross-section and fixed dimensions; and the conical transition straight waveguide 204 is a conical structure that gradually thickens. The large-diameter rectangular end of the platform transition straight waveguide 201 completely covers the output end face of the end coupler 303. The small-diameter rectangular port of the platform transition straight waveguide 201 is connected to the rectangular port of the mode shape conversion waveguide 202. The circular port of the mode shape conversion waveguide 202 is connected to the curved waveguide 203. The other end of the curved waveguide 203 is connected to the small-diameter port of the conical transition straight waveguide 204. The large-diameter circular port of the conical transition straight waveguide 204 is connected to the fiber array 301. The specific design steps of the curved waveguide 203 are as follows: First, based on the relative delay values ​​T1 to T2 of each channel obtained in the multi-channel delay measurement steps... n Assuming the first channel is the longest delay channel with a relative delay value of T1, then the relative delay difference between the remaining channels and the first channel is T1-T2 to T1-T. n By using information such as wavelength, photon lead refractive index, and delay difference, the physical length that the remaining channels need to increase relative to the first channel can be calculated to be L2 to L. n Next, the curved waveguide of the first channel is designed using the actual coordinates and direction vectors of the corresponding ports of the upper edge coupler 303 array and the fiber array 301, with a length of L1. Finally, based on the actual coordinates and direction vectors of the remaining channels, the trajectory of the curved waveguide 203 is changed so that the lengths of the curved waveguide 203 of the remaining channels are L1+L2 to L1+L2 respectively. n .like Figure 3 As shown.

[0148] Step 3: Photoresist Deposition: First, clean the devices. Immerse the optical computing chip 101, fiber array 301, and transparent optical substrate 306 sequentially in acetone and isopropanol solutions for 5 minutes and 3 minutes respectively, rinse with deionized water, and air dry. Then, using a coarse alignment device, fix the optical computing chip 101 and fiber array 301 onto the transparent optical substrate 306, ensuring that the height of the light output ports is basically consistent and the interconnect ports are basically aligned. Place the sample on a heating device such as an oven or hot plate and maintain the temperature at 100°C for 20 minutes. Remove and allow to cool naturally to room temperature. Finally, use a syringe 309 to drop photoresist 302 between the optical computing chip 101 and fiber array 301, and use a hot plate to bake the photoresist 302 to obtain a stable photoresist 302 layer. Figure 4 As shown.

[0149] Step 4: Photonic Lead Exposure: First, the photoresist-coated sample is placed on the displacement stage of the femtosecond laser platform. Then, according to the designed photonic lead 403 structure, the femtosecond laser focus 502 is controlled by the microscope lens 501 to expose the photoresist layer. The exposure strategy involves dividing the photonic lead 403 structure into multiple sections along the beam propagation direction. On each section, a polymer surface structure is formed through femtosecond laser exposure. The polymer surface structures 503 are then arranged sequentially in three-dimensional space to form the photonic lead structure, such as... Figure 4 As shown. The method for processing the polymer surface structure 503 includes the following steps: proportionally reducing the outer contour trajectory of each cross-section to form a concentric structure with the same center point. Each contour trajectory shares a center with other trajectories, and the size gradually decreases. For example, for a circular cross-section, it is divided into a concentric circle structure, and then all contours of the concentric structure are divided into multiple points, the spacing of which depends on the size of the laser focus 502. By controlling the laser focus 502 to sequentially expose the photoresist of the concentric structure from the inside out in the photoresist, the polymer surface structure 503 is formed. The polymer surface structures 503 are stacked to obtain a three-dimensional polymer bulk structure. Figure 5 and Figure 6 As shown.

[0150] Step 5: Photonic Lead Development: The unexposed photoresist 302 is removed through the development process, thereby forming the photonic lead 403 structure. The photonic lead 403 structure is used to realize the interconnection between the fiber array 301 and the edge coupler 101. Next, a low refractive index matching liquid 603 is dropped onto the photonic lead structure using a dropper 602 to form a waveguide cladding to isolate it from air. Figure 7 As shown.

[0151] Figure 3A schematic diagram illustrating the design steps of the photonic lead 403 structure in the technical solution of this invention is provided. The photonic lead 403 structure is divided into four parts: the first part 201 is a platform-type transition straight waveguide used to connect to the end-face coupler; the second part 202 is a mode shape conversion waveguide that converts a circular cross-section into a square cross-section; the third part 203 is a circular curved waveguide for single-mode transmission, used to compensate for multi-channel delay and alignment deviation; and the fourth part 204 is a conical transition straight waveguide used to connect to the fiber optic port. Specifically, the platform-type waveguide structure of the first part 201 has a large square cross-section, which perfectly covers the port of the end-face coupler, and its axis coincides with that of the end-face coupler 101. The mode shape converter of the second part 202 converts the circular waveguide cross-section into a square cross-section, and its axis coincides with the axis of the platform-type transition straight waveguide of the first part 201. The starting and ending directions of the curved waveguide of the third part 203 are the same as the directions of the waveguide axes connected at both ends, and its cross-section is circular with a radius that meets the requirements for single-mode transmission. The axis of the conical transition straight waveguide in Part 4, 204, coincides with the axis of the fiber core.

[0152] Figure 4 A schematic diagram of the photoresist deposition step in the technical solution of this invention is provided. First, photoresist is dropped onto the interconnect region using a syringe 309 to form a photoresist layer 302 covering the interconnect region. Next, the photoresist layer is baked using a heating device to remove the solvent, thereby obtaining a stable photoresist layer 302. The optical computing chip 101 modulates the multi-wavelength signals received by the end-face coupler 303 array through a delay line 307, a micro-ring resonator 305, and a wavelength division multiplexer 304 to complete the optical computing operation.

[0153] Figure 5 and Figure 6 The exposure strategy for the photonic lead in this invention is presented. The photonic lead 403 structure is divided into multiple sections along the light transmission direction, the number of sections depending on the size of the laser focus 502. Then, the outer contour trajectory of each section is scaled down proportionally, forming a concentric structure with the same center point. Each contour trajectory shares a center with other trajectories, and the size gradually decreases. For example, the outer contour of a circular section is circular, and it is divided into concentric circle structures, as shown in the interior of the rectangular section 405 and the interior of the circular section 406. By controlling the microscope lens 501 to perform point-by-point exposure inside each section, the change in the size of the laser focus 502 will result in different spacing between adjacent points. After the laser focus scans all points of the entire section from the inside to the outside, a dense polymer surface structure is finally formed. The polymer surface structures are stacked to obtain a three-dimensional polymer structure. All sections are processed sequentially according to the light transmission direction to finally form the complete photonic lead 403 structure.

[0154] Figure 7A schematic diagram of the waveguide cladding formed by drop-coating a low-refractive-index matching liquid in the technical solution of this invention is provided. After photoresist development, a complete photonic lead 403 is left between the fiber array 301 and the edge coupler 303. The photonic lead 403 achieves highly compact, delay-compensated, and coupled optical interconnection through transition waveguides and bent waveguides. The low-refractive-index matching liquid 603 is drop-coated onto the photonic lead 403 using a dropper 602, and after natural air drying, it forms the waveguide cladding, which serves to reduce waveguide loss and isolate air.

[0155] One embodiment of the present invention provides an integrated multi-channel delay compensation and coupling system for an optical computing chip.

[0156] Specifically, such as Figure 8 As shown, the integrated multi-channel delay compensation and coupling system for optical computing chips provided in this embodiment may include the following modules:

[0157] A multi-channel delay measurement module is used to measure the relative delay values ​​of the input and reference channels of the optical computing chip.

[0158] The photonic lead structure design module is used to obtain the actual port location information of the optical computing chip, and combine the delay values ​​of each channel and the photoresist refractive index of the photonic lead to design the photonic lead structure and obtain the photonic lead design structure.

[0159] The photoresist deposition module is used to clean and fix the optical computing chip and fiber array on a transparent substrate, and then apply photoresist to the interconnect area.

[0160] Photonic lead exposure module, which is used to expose the photonic lead structure point by point along the interior of the photonic lead design structure to form the photonic lead structure;

[0161] The photonic lead development module is used to remove unexposed photoresist and drop-coat a low-refractive-index matching liquid that matches the refractive index of the photoresist to form a waveguide cladding, thus completing the integrated multi-channel delay compensation and coupling function of the optical computing chip.

[0162] In a preferred embodiment of the present invention, the system further includes:

[0163] A marker deposition module is used to deposit positioning metal markers on the optical computing chip, which are used to locate the chip structure.

[0164] It should be noted that the steps in the method provided by the present invention can be implemented using corresponding modules, devices, units, etc. in the system. Those skilled in the art can refer to the technical solution of the method to realize the composition of the system. That is, the embodiments in the method can be understood as preferred examples for building the system, and will not be elaborated here.

[0165] The integrated multi-channel delay compensation and coupling method and system for optical computing chips provided in the above embodiments of the present invention, through an optical alignment platform, connects one end of the input channel and reference channel of the optical computing chip to a broadband light source via optical fiber, and the other end to a photodetector via optical fiber. The photodetector converts the optical signal into an electrical signal and transmits the electrical signal to the input channel of an oscilloscope. The delay of each input channel is then measured by the oscilloscope. Information such as the actual position of the port is obtained by using the imaging system of the femtosecond laser platform. Combined with information such as the relative delay difference of each channel and the refractive index of the photoresist, a photonic lead structure is designed. The optical computing chip and fiber array are cleaned and fixed on a transparent substrate. Then, photoresist is deposited onto the interconnection area, and finally, it is placed on a heating device to complete the photoresist baking. The femtosecond laser focus is controlled to expose the photonic lead structure point by point along the interior of the designed photonic lead structure to form the photonic lead structure. The unexposed photoresist is removed by developing solution, and a low refractive index matching liquid is deposited to form a waveguide cladding. The method and system provided in the above embodiments of the present invention utilize the two-photon polymerization effect of femtosecond lasers to fabricate photonic lead structures, thereby achieving highly compact, delay-compensated, and coupled multi-channel inter-chip interconnects.

[0166] Any matters not covered in the above embodiments of the present invention are well-known in the art.

[0167] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. An integrated multi-channel delay compensation and coupling method for optical computing chips, characterized in that, The method comprises the following steps: Measuring the multi-channel relative delay values of the input channels and reference channels of the optical computing chip; Obtaining the actual positions and geometric size information of the ports of the optical computing chip, and combining the relative delay values of the channels and the photoresist refractive index of the photonic lead, to design the photonic lead structure and obtain the photonic lead design structure; Cleaning the optical computing chip and the fiber array and fixing them on a transparent substrate, and then using photoresist to drop on the interconnection area; Exposing the photonic lead structure point by point along the inside of the photonic lead design structure to form the photonic lead structure; Removing the unexposed photoresist, and dropping a low refractive index matching liquid matching the photoresist refractive index to form a waveguide cladding, to complete the integrated multi-channel delay compensation and coupling of the optical computing chip; The method of obtaining the actual positions and geometric size information of the ports of the optical computing chip, and combining the relative delay values of the channels and the photoresist refractive index of the photonic lead, to design the photonic lead structure and obtain the photonic lead design structure, comprises the following steps: Using the imaging system of the femtosecond laser platform to detect the actual positions and direction angles of the port of the end face coupler and the port of the fiber array of the optical computing chip; According to the port size, actual coordinates, direction vector of the end face coupler and the fiber array, and the relative delay value information of each channel, a segmented photonic lead structure is designed to obtain the photonic lead design structure; The photonic lead design structure comprises a platform transition straight waveguide, a mode spot shape conversion waveguide, a curved waveguide and a conical transition straight waveguide; wherein: The platform transition straight waveguide is a cubic waveguide structure that becomes thick from thin, the large-aperture rectangular end of the platform transition straight waveguide completely covers the light-emitting end face of the end face coupler, and the small-aperture rectangular end of the platform transition straight waveguide is connected to the rectangular port of the mode spot shape conversion waveguide; The mode spot shape conversion waveguide is a cylindrical waveguide structure that transitions from rectangular to circular, and the circular port of the mode spot shape conversion waveguide is connected to the curved waveguide; The curved waveguide is a curved cylindrical waveguide structure with a circular cross section and a fixed size, and the other end of the curved waveguide is connected to the small-aperture port of the conical transition straight waveguide; by designing the trajectory of the curved waveguide, the delay compensation of each channel is realized; The conical transition straight waveguide is a tapered waveguide structure that becomes thick from thin, and the large-aperture port of the conical transition straight waveguide is connected to the fiber array; Further comprising: The radius of the circular cross section of the curved waveguide should meet the demand of single-mode transmission of optical signals; The trajectory of the curved waveguide is designed, comprising: According to the relative delay values of the channels , assuming that the first channel is the longest delay channel, and its relative delay value is , then the relative delay difference between the remaining channels and the first channel is , through the wavelength, the photoresist refractive index, and the relative delay difference information, the physical length that the remaining channels need to increase relative to the first channel is calculated as ; actual coordinates of the end face coupler and the end face of the fiber array of the first channel and and the unit directional vector and the value of is adjusted by optimization so that the loss is minimized, and finally the curved waveguide trajectory of the first channel is obtained, then the length of the curved waveguide of the first channel is wherein, , and respectively represent , and the first order derivative with respect to the parameter t; wherein: wherein represents the total loss of the curved waveguide of the first channel, represents the material absorption and surface scattering coefficients of the curved waveguide, represents the inverse of the radius of curvature of the curved waveguide of the first channel, t represents a parameter of the trajectory equation and , represents a direction vector along the curved waveguide trajectory of the first channel, and respectively represent the first and second order derivatives with respect to the parameter t; According to the end surface coordinates of the end surface coupler and the optical fiber array of the remaining channel And And the unit directional vector And Under the constraint condition that the length of the curved waveguide of the newly added remaining channel is , the same reason is obtained by optimizing the minimum The trajectory equation of the remaining channel is , wherein the number of channels .

2. The integrated multi-channel delay compensation and coupling method of the photonic computing chip according to claim 1, wherein, The method of measuring the multi-channel relative delay values of the input channels and reference channels of the optical computing chip comprises the following steps: Through the optical alignment platform, one end of the input channels and reference channels of the optical computing chip is connected to a broadband light source through an optical fiber, and the other end of the input channels and reference channels of the optical computing chip is connected to a photodetector through an optical fiber, the optical signal is converted into an electrical signal by the photodetector, and the electrical signal is transmitted to the input channel of an oscilloscope, and the relative delay values of each channel are measured by the oscilloscope; Wherein: The method of measuring the relative delay values of each channel by the oscilloscope comprises the following steps: Adjust the displacement of the fiber optic clamp to obtain the best optical coupling effect; Analyze the signals obtained from the oscilloscope to obtain the amplitude response of each channel; Based on the amplitude response of each channel, the phase response of each channel is calculated using the KK relationship, and then the phase information in the frequency domain is converted into the phase information in the time domain through inverse Fourier transform, from which the relative delay value of each channel is obtained.

3. The integrated multi-channel delay compensation and coupling method of photonic computing chips of claim 1, wherein, The process of cleaning and fixing the optical computing chip and fiber array onto a transparent optical substrate, followed by photoresist deposition onto the interconnect area, includes: The optical computing chip, fiber array, and transparent optical substrate were cleaned using organic solvents, and the optical computing chip and fiber array were fixed on the transparent optical substrate. Heating equipment is used to remove residual organic solvents and moisture; Depositing photoresist between the optical computing chip and the fiber array; in: The transparent optical substrate is a stepped glass slide or a sapphire film.

4. The integrated multi-channel delay compensation and coupling method of photonic computing chips of claim 1, wherein, The process of forming the photonic lead structure by point-by-point exposure along the interior of the photonic lead design structure includes: The coated sample is placed on the displacement stage of the femtosecond laser platform; Based on the aforementioned photonic lead design structure, the femtosecond laser focus is controlled to expose the photoresist layer point by point. in: The step of controlling the femtosecond laser focus to expose the photoresist layer point by point according to the photonic lead design structure includes: The photonic lead design structure is divided into n sections along the beam propagation direction. The outer contour trajectory of each section is scaled down proportionally to form a concentric structure with the same center point; Divide all the contours of each concentric structure into m points; By controlling the femtosecond laser focus and moving it to one of the points, the process of turning on the femtosecond laser exposure, turning off the femtosecond laser, and moving to the next point is executed, so that the femtosecond laser is exposed only at that point, resulting in a polymer dot structure. By performing the above process, the concentric structure is exposed point by point in the photoresist from the inside out to obtain a polymer surface structure; the polymer surface structures are stacked to form a three-dimensional polymer body structure to obtain a photonic lead structure.

5. The integrated multi-channel delay compensation and coupling method of photonic computing chips according to any one of claims 1-4, wherein, Also includes: Deposit and position metal markers on the optical computing chip; wherein: The mark is either rectangular or triangular in shape; The markings are located on both arms of the end coupler and are symmetrical about their axis. The number of markers depends on the length of the end face coupler.

6. A coupling system implementing the integrated multi-channel delay compensation and coupling method of the optical computing chip of claim 1, wherein, include: A multi-channel delay measurement module is used to measure the relative delay values ​​of the input and reference channels of an optical computing chip. The photonic lead structure design module is used to obtain the actual port location and geometric dimension information of the optical computing chip, and combine the relative delay value of each channel and the photoresist refractive index of the photonic lead to design the photonic lead structure and obtain the photonic lead design structure. The photoresist deposition module is used to clean and fix the optical computing chip and fiber array onto a transparent substrate, and then use photoresist to drop and coat the interconnect area. A photonic lead exposure module, which is used to expose point by point along the interior of the photonic lead design structure to form a photonic lead structure; The photonic lead development module is used to remove unexposed photoresist and drop-coat a low refractive index matching liquid that matches the refractive index of the photoresist to form a waveguide cladding, thereby completing the integrated multi-channel delay compensation and coupling of the optical computing chip.

7. The integrated multi-channel delay compensation and coupling system of the photonic computing chip of claim 6, wherein, Also includes: The marking deposition module is used to deposit positioning metal markers on the optical computing chip.

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