Point diffraction interference system and method based on on-chip regulation and control
By integrating light injection, intensity modulation, phase modulation, and detection modules into a nanowire waveguide point diffraction source, the problem of low system integration was solved, achieving high integration and stable optical signal processing, and forming an approximately ideal diffractive spherical wave.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-22
- Publication Date
- 2026-03-31
AI Technical Summary
Existing technologies have failed to effectively combine the advantages of optical signal processing and transmission, resulting in low system integration of nanowire waveguide point diffraction light sources and an inability to fully realize the potential of integrated optical miniaturization and optical signal processing.
An on-chip controlled point diffraction interferometry system is adopted, including a light injection module, an intensity control module, a phase control module, a light source interference module, and a phase detection module. By integrating these modules on an on-chip platform, the point diffraction light source of the nanowire waveguide can be controlled to achieve localization and diffraction of the light field.
It significantly improves the integration and stability of the interferometric system, achieves a larger numerical aperture and a near-ideal diffractive spherical wave, and enhances the system's application potential.
Smart Images
Figure CN121762043A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optical technology, and in particular to a point diffraction interferometry system and method based on on-chip control. Background Technology
[0002] Point diffraction interferometry utilizes wavelength-scale microstructures to generate ideal diffracted spherical waves, which serve as both reference and target waves for interferometric measurements. Traditional point diffraction sources include pinhole and fiber point diffraction. The former generates waves with high numerical apertures through micro-apertures, but with relatively low light intensity; the latter uses fiber endfaces, achieving higher light intensity, but typically with a numerical aperture less than 0.2. Waveguide point diffraction, employing nanowire waveguides, can achieve numerical apertures up to 0.5 and relatively high light intensity, demonstrating its potential in integrated optics.
[0003] However, current research mainly focuses on single-chip structures, failing to effectively combine the advantages of optical signal processing and transmission, thus limiting the development of system performance and miniaturization. Traditional spatial light modulation methods are flexible but their accuracy is limited by environmental interference, while fiber optic modulation systems, although stable, have low integration, leading to bottlenecks in overall system integration.
[0004] Therefore, how to improve the integration of the interference system, while providing an effective on-chip control method for point diffraction light sources based on nanowire waveguides, and leveraging the advantages of integrated optics miniaturization and optical signal processing, is a technical problem that urgently needs to be solved. Summary of the Invention
[0005] This application provides a point diffraction interferometry system and method based on on-chip control, which provides an effective on-chip control means for point diffraction light sources based on nanowire waveguides, and achieves the technical effect of improving the integration of the interferometry system.
[0006] To achieve the above objectives, the main technical solutions adopted in this application include: In a first aspect, embodiments of this application provide a point diffraction interferometry system based on on-chip control. The system includes a light injection module, an intensity control module, a phase control module, a light source interference module, and a phase detection module connected sequentially. The optical injection module is used to couple external laser light to the on-chip waveguide and output it to two waveguides; The intensity control module is used to independently adjust the transmission light intensity of the two waveguides and output the intensity-modulated two transmission lights. The phase modulation module is used to adjust the effective refractive index of the two waveguides in which the two intensity-modulated transmission lights are located, so as to adjust the phase difference of the two intensity-modulated transmission lights and output the two phase-modulated transmission lights. The light source interference module is used to use the two waveguides containing the two phase-modulated transmission lights as nanowire waveguide point diffraction light sources, so as to realize point diffraction when the two phase-modulated transmission lights pass through the end face of the nanowire waveguide, and the interference of the two point diffracted light waves generates interference fringes for application. The phase detection module is used to extract the two phase-modulated transmitted beams, perform on-chip interference, and output phase detection beams for phase detection.
[0007] In one embodiment, the optical injection module includes an input coupler, a polarization controller, and an input beam splitter connected in sequence; wherein, The input coupler is used to couple the external laser to the on-chip waveguide; The polarization controller is used to adjust the coupled light into a single beam of light with a single polarization state. The input beam splitter is used to split the single beam of light into two transmission beams to two waveguides.
[0008] In one embodiment, the input coupler is an end-face coupler or a grating coupler.
[0009] In one embodiment, the intensity control module includes two intensity control units with identical structures and independent of each other; wherein, each intensity control unit includes a first beam splitter, a double-arm heating electrode, and a second beam splitter connected in sequence. The first beam splitter is used to split one of the two waveguide transmission beams into upper and lower arm transmission beams. The dual-arm heating electrodes are used to apply voltage to the waveguides where the upper and lower arms transmit light, adjust the effective refractive index of the two arm waveguides, and thus adjust the phase difference between the upper and lower arms transmit light. The second beam splitter is used to combine the transmitted light from the upper and lower arms after adjusting the phase difference to achieve intensity modulation.
[0010] In one embodiment, the phase modulation module includes a heating electrode disposed on one of the two waveguides; wherein, The heating electrode is used to apply a voltage to the waveguide where one transmission light is located, thereby adjusting the effective refractive index of the waveguide relative to the other waveguide, and thus adjusting the phase difference between the transmission light and the other transmission light, and outputting two phase-modulated transmission lights.
[0011] In one embodiment, the heating electrode is based on the thermo-optic effect, changing the effective refractive index of the corresponding waveguide by applying a voltage.
[0012] In one embodiment, the phase detection module includes directional couplers connecting the waveguides containing the two phase-modulated transmission beams, as well as an output beam combiner, a cross waveguide, and an output coupler; wherein, Each directional coupler is used to extract the optical power of the two phase-modulated transmitted lights according to a preset ratio to obtain two sampled lights; The output beam combiner is used to interferometrically combine the two sampled beams to obtain phase detection beam; The cross waveguide is used to guide the phase detection light to the output coupler; The output coupler is used to output the phase detection light outside the chip for phase detection.
[0013] In one embodiment, the system has a core layer structure, which includes a core layer and a cladding layer; wherein, when controlling the visible light band, the core layer is made of silicon nitride and the cladding layer is made of silicon dioxide.
[0014] Secondly, embodiments of this application provide a nanowire waveguide point diffraction light source obtained according to the above-described on-chip controlled point diffraction interference system. The transmitted light propagates in the core layer of the nanowire waveguide. Based on the refractive index difference between the core layer and the cladding, the nanowire waveguide confines the transmitted light field to the wavelength or subwavelength level to achieve light field localization. In this case, the light field emitted at the end face undergoes diffraction to form a diffracted spherical wave that meets preset requirements and has at least a specified numerical aperture.
[0015] Thirdly, embodiments of this application provide an on-chip control method based on a nanowire waveguide point diffraction source, wherein the method: The optical injection module couples external laser light to the on-chip waveguide and outputs it to two waveguides; The intensity control module independently adjusts the transmitted light intensity of the two waveguides and outputs the intensity-modulated transmitted light from the two waveguides. The phase modulation module modulates the effective refractive index of the two waveguides containing the intensity-modulated two transmitted beams to control the phase difference between the intensity-modulated two transmitted beams and outputs the phase-modulated two transmitted beams. The light source interference module uses the two waveguides containing the two phase-modulated transmission beams as nanowire waveguide point diffraction light sources to achieve point diffraction when the two phase-modulated transmission beams pass through the end face of the nanowire waveguide, and the interference of the two point diffracted light waves generates interference fringes for application. The phase detection module extracts the two phase-modulated transmitted beams, performs on-chip interference, and outputs phase detection beams for phase detection.
[0016] The technical solutions provided by one or more embodiments of this application integrate a light injection module, an intensity control module, a phase control module, a light source interference module, and a phase detection module onto a single on-chip platform. This integrated design significantly improves the integration level of the interference system. Furthermore, the nanowire waveguide point diffraction light source obtained by this on-chip controlled point diffraction interference system can diffract to form a diffracted wave sphere that meets preset requirements (approximately ideal) when emitted from the end face, and can achieve a larger numerical aperture, thereby enhancing the application potential of the system.
[0017] As can be seen, the technical solution provided in this application uses various on-chip modulation modules to control the nanowire waveguide point diffraction source, providing it with on-chip control means and realizing system integration, which significantly improves the compactness, stability and environmental adaptability of the point diffraction interferometry system. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0019] Figure 1 A schematic diagram of a point diffraction interferometry system based on on-chip control provided in an embodiment of this application; Figure 2 A schematic diagram illustrating a specific implementation of a point diffraction interferometry system based on on-chip control, provided in an embodiment of this application; Figure 3 The dual-waveguide interference fringes with Φ=0 are generated by simulation in the embodiments of this application; Figure 4 The dual-waveguide interference fringes with Φ=π / 2 generated by simulation are provided in the embodiments of this application; Figure 5 The dual-waveguide interference fringes with Φ=π generated by simulation are provided in the embodiments of this application; Figure 6 The dual-waveguide interference fringes with Φ=3*π / 2 generated by simulation are provided in the embodiments of this application; Figure 7 The actual interference image generated by the point diffraction interferometry system based on on-chip control is provided in the embodiments of this application; Figure 8 The optical power provided in the embodiments of this application varies with the square of the applied voltage (V) 2 The curve of change; Figure 9A schematic diagram of a system for measuring objective wavelet aberrations using a point diffraction interferometry system based on on-chip control, provided for an embodiment of this application; Figure 10 This is a flowchart illustrating an on-chip control method for a nanowire waveguide point diffraction source, as provided in an embodiment of this application.
[0020] Explanation of reference numerals in the attached figures Input coupler 1, polarization controller 2, input beam splitter 3, first beam splitter 4, 7, dual-arm heating electrode 5, 8, second beam splitter 6, 9, heating electrode 10, directional coupler 11, 12, output beam combiner 13, cross waveguide 14, output coupler 15. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0022] With technological advancements, nanowire waveguide-based point diffraction light sources can achieve stable single-mode optical field transmission on a smaller scale, confining the optical field to the wavelength and subwavelength levels. The wavefront generated by its point diffraction exhibits near-ideal spherical waves while possessing greater intensity compared to pinhole point diffraction, and a larger numerical aperture compared to fiber point diffraction, offering advantages. However, current nanowire waveguide-based point diffraction light source solutions also have limitations. Modulation of the light source relies on off-chip spatial optical systems or fiber optic systems. The former is susceptible to environmental influences and is bulky, while the latter, although isolating from environmental interference, faces bottlenecks in further improving its integration. This limitation prevents the full utilization of the advantages of integrated optical platforms in optical signal transmission and processing, thus affecting the system's flexibility and tunability.
[0023] In summary, improving the integration of interferometric systems and providing effective on-chip control methods for point diffraction light sources based on nanowire waveguides are urgent technical problems that need to be solved.
[0024] To address the aforementioned technical problems, one or more embodiments of this application provide a point diffraction interferometry system based on on-chip control. Figure 1 A schematic diagram of a point diffraction interferometry system based on on-chip control is provided for an embodiment of this application, as shown below. Figure 1 As shown, the system includes a light injection module, an intensity control module, a phase control module, a light source interference module, and a phase detection module connected in sequence; wherein, The optical injection module is used to couple external laser light to the on-chip waveguide and output it to two waveguides; The intensity control module is used to independently adjust the transmission light intensity of the two waveguides and output the intensity-modulated transmission light of the two waveguides. The phase modulation module is used to adjust the effective refractive index of the two waveguides containing the two intensity-modulated transmission beams, so as to adjust the phase difference of the two intensity-modulated transmission beams and output the two phase-modulated transmission beams. The light source interference module is used to use the two waveguides containing the two phase-modulated transmission beams as nanowire waveguide point diffraction light sources, so as to realize point diffraction when the two phase-modulated transmission beams pass through the end face of the nanowire waveguide, and the interference of the two point diffracted light waves generates interference fringes for application. The phase detection module is used to extract the two phase-modulated transmitted beams, perform on-chip interference, and output phase detection beams for phase detection.
[0025] Specifically, the optical injection module couples an external laser beam into the on-chip controlled point diffraction interferometry system and outputs it to two waveguides. This process is the initial stage of the system, ensuring that the external light source (such as a laser) can enter the optical waveguides and be transmitted to subsequent modules. The intensity control module independently adjusts the transmitted light intensity of the two waveguides, so that the output transmitted light has the required intensity modulation. Through intensity adjustment, the system can control the intensity of the transmitted light in each waveguide, thereby controlling the output light intensity of the two output waveguides, i.e., controlling the intensity of the nanowire waveguide point diffraction source. After intensity adjustment, there may be a phase difference between the transmitted light in the two waveguides. In addition, the effective refractive index of the two waveguides is finely adjusted by the phase control module. The core function of this module is to ensure that the transmitted light in the two waveguides has an appropriate phase relationship, so as to adjust the phase difference of the output light from the two nanowire waveguide point diffraction sources, thereby achieving phase shifting operation. The phase detection module samples the transmitted light from the two phase-modulated waveguides through a directional coupler, and then combines them to form a detection light. The change in the intensity of the detection light can reflect the change in the phase difference between the transmitted light in the two waveguides.
[0026] The nanowire waveguide point diffraction source effectively compensates for the low light intensity of pinhole point diffraction and the small numerical aperture of fiber point diffraction. At the same time, combined with the above-mentioned on-chip control module, it fully leverages the advantages of the nanowire waveguide point diffraction source on the integrated optical platform, realizing on-chip control of the nanowire waveguide point diffraction source and improving the system's integration and accuracy.
[0027] Please see Figure 2 The specific implementation of the present invention will now be described.
[0028] Step S1001: Light Injection and Initialization Light enters the point diffraction interference system based on on-chip control from the input coupler 1. After polarization state normalization is completed by the polarization controller 2, the single beam of light is uniformly split into two beams by the multimode interferometer (MMI) of the input beam splitter 3, which enter waveguide A and waveguide B respectively. At this time, the two waveguides are in phase and have equal intensity.
[0029] Step S1002: Independent intensity control (parallel processing) The two waveguides each enter their respective intensity modulation units: Waveguide A: sequentially passes through first beam splitter 4 (MMI beam splitter) → dual-arm heating electrode 5 → second beam splitter 6 (MMI beam combiner). Waveguide B: sequentially passes through first beam splitter 7 (MMI beam splitter) → dual-arm heating electrode 8 → second beam splitter 9 (MMI beam combiner). Control mechanism: A differential voltage is applied to the upper and lower waveguides of the dual-arm heating electrode 5 (or dual-arm heating electrode 8), and a phase difference is introduced by utilizing the thermo-optic effect. The transmitted light from the upper and lower arms interferes at the second beam splitter 6 (or second beam splitter 9). The intensity of the transmitted light is continuously adjustable as the phase difference changes. In this way, the intensity of the two transmitted light paths A and B can be set independently.
[0030] Step S1003: Precise phase control (differential modulation) The two transmitted beams continue forward, with the heating electrode 10 now covering only waveguide A. By adjusting the voltage of the heating electrode 10, the effective refractive index of waveguide A is changed, creating a controllable optical path difference relative to waveguide B, thereby achieving precise control of the relative phase difference Δφ between the two waveguides. At this point, waveguides A and B have achieved independent intensity and phase control.
[0031] Step S1004: Interference output of nanowire waveguide point diffraction source Waveguide A, where the phase-modulated transmitted light is located, and waveguide B, where the intensity-modulated transmitted light is located, serve as point diffraction sources for the nanowire waveguides, respectively. When the phase-modulated and intensity-modulated transmitted light passes through the end face of the nanowire waveguides, point diffraction occurs, and interference fringes are generated by the interference of the two point diffracted light waves for application.
[0032] Step S1005: Phase detection and signal acquisition (in-situ monitoring) The phase-modulated transmitted light from waveguide A reaches directional coupler 11, and the intensity-modulated transmitted light from waveguide B reaches directional coupler 12. The directional coupler 11 extracts a fixed proportion (e.g., 5%) of the transmitted light from waveguide A and couples it downward to the detection branch; The directional coupler 12 extracts the same proportion of transmitted light from waveguide B and couples it upward to the detection branch; The two sampled beams meet and interfere with each other at the output combiner 13 (MMI combiner) to form a phase detection beam. This phase detection beam carries the relative phase information of the phase-modulated and intensity-modulated transmission beams. Cross waveguide 14 ensures low crosstalk between the phase detection light and the main beam of waveguide B, and the phase detection light is finally output by output coupler 15 for real-time reading by an external detector. Δφ can be demodulated in reverse through calibration, achieving phase closed-loop monitoring.
[0033] This system achieves beam separation, modulation, and recombination, utilizing the thermo-optical effect to control intensity and phase. Finally, point diffraction is performed through two nanowire waveguides, outputting two intensity- and phase-modulated diffracted spherical waves that interfere with each other. A directional coupler and an MMI beam combiner structure are introduced to achieve on-chip phase self-detection. This provides an integrated on-chip control and detection solution for current nanowire waveguide point diffraction light sources.
[0034] This application provides a nanowire waveguide point diffraction source obtained based on an on-chip controlled point diffraction interferometry system. The nanowire waveguide, located near the exit face after the phase modulation module, is the nanowire waveguide point diffraction source. In the system, the transmitted light propagates in the core layer of the nanowire waveguide. Based on the refractive index difference between the core and cladding, the nanowire waveguide confines the transmitted light field to the wavelength or subwavelength level, achieving light field localization. Therefore, when the light field exits from the end face, diffraction occurs, forming an approximately ideal diffracted spherical wave and achieving a large numerical aperture.
[0035] For example, to verify whether the spherical waves generated by the two nanowire waveguide point diffraction sources conform to expectations when the obtained nanowire waveguide point diffraction source passes through the end face of the nanowire waveguide, an ideal spherical wave simulation was performed to obtain the reference interference image distribution. The specific simulation parameters are as follows: In a Cartesian coordinate system, two nanowire waveguide point diffraction sources, S1 and S2, are spaced d = 20 μm apart and located at coordinate positions S1(-10 μm, 0, 0) and S2(10 μm, 0, 0), respectively. A detection screen is set at z = 20 mm, with an image pixel resolution of 1920 × 1200 pixels, corresponding to actual physical dimensions of 11.251 × 7.032 mm. The interference fringes formed on the detection screen by the point diffracted light waves emitted from these two nanowire waveguide point diffraction sources will be simulated and analyzed. The results are as follows... Figures 3 to 6 The simulation image results. Among them, Figure 3 The double waveguide interference fringes when Φ=0; Figure 4 The double waveguide interference fringes are when Φ=π / 2; Figure 5 The double waveguide interference fringes are when Φ=π; Figure 6The image shows the interference fringes of a double-waveguide interference pattern when Φ = 3π / 2. This demonstrates the distribution of the interference image obtained from the interference of two ideal spherical waves generated by a point source, and the effect of phase shift on the fringes. By using five double-waveguide interference fringe images with a fixed phase difference, the wavefront information of this interference image can be calculated using a five-step phase-shifting method. During the phase shift, the interference fringes also shift accordingly.
[0036] Exemplarily, this application provides a point diffraction interferometry system based on on-chip control, using a silicon nitride nanowire waveguide as the waveguide core and silicon dioxide as the cladding. The silicon nitride material has a refractive index of 1.96, a preferred height of 200 nm, and a preferred width of 230 nm. The silicon dioxide material has a refractive index of 1.46, a cladding thickness of 4 μm, an operating wavelength range of 633 nm, and an operating polarization state of TE polarization. When the obtained nanowire waveguide point diffraction source passes through the end face of the nanowire waveguide, point diffraction occurs. The approximately ideal spherical waves generated by the two nanowire waveguide point diffraction sources are measured. The CMOS sensor collecting the interference fringes is positioned at z = 23 mm, and the output image pixel resolution of the CMOS sensor is 1920 × 1200 pixels, corresponding to an actual physical size of 11.251 × 7.032 mm. Figure 7 It can be seen that the generated interference image is similar to the simulation result, with clear fringes and good contrast, and its interference fringe distribution has the characteristics of two spherical wave interferences.
[0037] In one embodiment, a silicon nitride nanowire waveguide is used as the waveguide core layer, and silicon dioxide is used as the cladding layer. The heating electrodes for the phase modulation module and intensity modulation module in the on-chip controlled point diffraction interferometry system are preferably designed with a length of 400 μm, allowing the phase quantity to be adjusted within a 20V voltage range. When the voltage source resolution is 0.001V, its phase shift accuracy can reach [percentage missing]. This enables precise intensity and phase control of nanowire waveguide point diffraction sources. Please refer to [link / reference]. Figure 8 The optical power provided in the embodiments of this application varies with the square of the applied voltage (V) 2 The curve showing the change in V. The horizontal axis is based on V. 2 20V corresponds exactly to a complete 2π phase period. Due to process errors, the initial operating point is not strictly at φ=0, but slightly offset downwards; this offset is within the allowable range, and it is sufficient to ensure that the phase modulation range covers 2π. The curve is a standard sine wave, and the periodic change in light intensity directly reflects the phase modulation depth, confirming that the point diffraction interferometry system based on on-chip control in this application has complete phase modulation capability.
[0038] In one embodiment, an on-chip controlled nanowire waveguide point diffraction interferometry system is applied to objective lens wavefront aberration measurement. For example... Figure 9 This is a schematic diagram of a system for measuring objective wavefront aberrations using an on-chip controlled point diffraction interferometry system, provided in an embodiment of this application. The on-chip controlled point diffraction source has two nanowire waveguides, A and B. Waveguides A and B, located on the object plane, generate ideal wavefronts, one serving as a reference beam and the other as a test beam. Both beams are imaged through the objective lens under test onto a mask located on the image plane. The mask includes a pinhole and an optical window, and a precision displacement stage is located below to achieve micro-displacement of the mask. One beam passes through the pinhole, and the other through the optical window, forming a point diffraction measurement mode as shown below. Figure 9 In (a), both beams pass through the optical window to form a systematic error measurement mode, as shown in (a). Figure 9 In (b), two beams of light intersect at the photosensitive surface of the CMOS camera on the image plane, forming interference fringes that are captured by the CMOS camera. Intensity or phase modulation of the two beams yields a high-quality phase-shifted image, which is then processed by a computer unit for phase plane reconstruction to obtain the wavefront aberration information of the objective lens under test. The results obtained from the calibration point diffraction measurement mode can be used to calibrate the results from the systematic error measurement mode, thus achieving the purpose of systematic error removal.
[0039] Accordingly, please refer to Figure 10 A flowchart of a point diffraction interferometry method based on on-chip control provided in this application embodiment, the method comprising: Step S1: The external laser is coupled to the on-chip waveguide through the optical injection module and output to the two waveguides; Step S3: The intensity of the transmitted light from the two waveguides is independently adjusted by the intensity control module, and the intensity-modulated transmitted light from the two waveguides is output. Step S5: The effective refractive index of the two waveguides containing the two intensity-modulated transmission lights is adjusted by the phase modulation module to adjust the phase difference of the two intensity-modulated transmission lights and output the two phase-modulated transmission lights. Step S7: The two waveguides containing the two phase-modulated transmission beams are used as nanowire waveguide point diffraction sources by the light source interference module, so as to realize point diffraction when the two phase-modulated transmission beams pass through the end face of the nanowire waveguide, and interference fringes are generated by the interference of the two point diffracted light waves for application. Step S9: The phase-modulated two-way transmission light is extracted by the phase detection module, and on-chip interference is performed to output phase detection light for phase detection.
[0040] In some optional implementations, the optical injection module includes an input coupler, a polarization controller, and an input beam splitter connected in sequence; wherein, Input coupler, used to couple external laser light to the on-chip waveguide; A polarization controller is used to adjust coupled light into a single beam of light with a single polarization state. The input beam splitter is used to split a single beam of light into two transmission beams to two waveguides.
[0041] In some alternative implementations, the input coupler is an end-face coupler or a grating coupler.
[0042] In some optional embodiments, the intensity control module includes two intensity control units with identical structures and independent of each other; wherein each intensity control unit includes a first beam splitter, a double-arm heating electrode and a second beam splitter connected in sequence. The first beam splitter is used to split one of the two waveguides into upper and lower arm beams. The dual-arm heating electrodes are used to apply voltage to the waveguides in which the upper and lower arms transmit light, thereby adjusting the effective refractive index of the two waveguides and thus adjusting the phase difference between the upper and lower arms transmitted light. The second beam splitter is used to combine the transmitted light from the upper and lower arms after adjusting the phase difference to achieve intensity modulation.
[0043] In some alternative implementations, the phase modulation module includes a heating electrode disposed on one of the two waveguides; wherein, The heating electrode is used to apply a voltage to the waveguide where one transmitted light is located, thereby adjusting the effective refractive index of the waveguide relative to the other waveguide, and thus adjusting the phase difference between the transmitted light and the other transmitted light, and outputting two phase-modulated transmitted lights.
[0044] In some alternative implementations, the heating electrode is based on the thermo-optic effect, changing the effective refractive index of the corresponding waveguide by applying a voltage.
[0045] In some optional implementations, the light source interference module includes two waveguides containing the two phase-modulated transmission beams. The two waveguides containing the two phase-modulated transmission beams serve as nanowire waveguide point diffraction light sources, which are used to cause point diffraction when the two phase-modulated transmission beams pass through the end face of the nanowire waveguides. The interference of the two point diffracted light waves generates interference fringes for application.
[0046] In some optional implementations, the phase detection module includes directional couplers connecting the waveguides containing the two phase-modulated transmission beams, as well as an output beam combiner, a cross waveguide, and an output coupler; wherein, Each directional coupler is used to extract the optical power of the two phase-modulated transmitted lights according to a preset ratio, and obtain two sampled lights. The output beam combiner is used to combine the two sampled beams by interference to obtain the phase detection beam; Cross waveguides are used to guide the phase detection light to the output coupler; Output coupler, used to output phase detection light off-chip for phase detection.
[0047] In some alternative implementations, the system has a core structure, which includes a core layer and a cladding layer; wherein, when controlling the visible light band, the core layer is made of silicon nitride and the cladding layer is made of silicon dioxide.
[0048] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.
[0049] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0050] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the method embodiments are basically similar to the system embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the system embodiments.
[0051] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.
[0052] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and such modifications and variations all fall within the scope defined by the appended claims.
Claims
1. A point-diffraction interferometer system based on on-chip steering, characterized in that, The system comprises, in sequence, a light injection module, an intensity regulation module, a phase regulation module, a light source interference module, and a phase detection module. The light injection module is configured to couple external laser light to an on-chip waveguide and output the light to two waveguides. The intensity regulation module is configured to independently regulate the transmission light intensity of the two waveguides and output the two transmission lights after intensity modulation. The phase regulation module is configured to regulate the effective refractive index of the two waveguides on which the two transmission lights after intensity modulation are located, so as to regulate the phase difference of the two transmission lights after intensity modulation, and output the two transmission lights after phase modulation. The light source interference module is configured to take the two waveguides on which the two transmission lights after phase modulation are located as nanowire waveguide point-diffraction light sources, so as to cause point diffraction of the two transmission lights after phase modulation when passing through the end face of the nanowire waveguide, and generate interference fringes through interference of the two point-diffraction light waves. The phase detection module is configured to extract the two transmission lights after phase modulation for on-chip interference and output phase detection light for phase detection.
2. The system of claim 1, wherein, The light injection module comprises, in sequence, an input coupler, a polarization controller, and an input beam splitter. The input coupler is configured to couple the external laser light to the on-chip waveguide. The polarization controller is configured to adjust the coupled light into single-polarization single-beam light. The input beam splitter is configured to divide the single-beam light into two transmission lights to the two waveguides.
3. The system of claim 2, wherein, The input coupler is an end-face coupler or a grating coupler.
4. The system of claim 1, wherein, The intensity regulation module comprises two intensity regulation units which are identical in structure and independent of each other. Any intensity regulation unit comprises, in sequence, a first beam splitter, a double-arm heating electrode, and a second beam splitter. The first beam splitter is configured to divide one of the two transmission lights into upper and lower arm transmission lights. The double-arm heating electrode is configured to apply a voltage to the waveguide on which the upper and lower arm transmission lights are located, regulate the effective refractive index of the two arm waveguides, and thereby regulate the phase difference between the upper and lower arm transmission lights.
5. The system of claim 1, wherein, The second beam splitter is configured to output the upper and lower arm transmission lights after phase difference regulation through interference and combination, so as to complete intensity modulation. The phase regulation module comprises a heating electrode arranged on one of the two waveguides.
6. The system of claim 5, wherein, The heating electrode is configured to regulate the effective refractive index of the waveguide relative to the other waveguide by applying a voltage to the waveguide on which one of the transmission lights is located, thereby regulating the phase difference of the transmission light relative to the other transmission light, and outputting the two transmission lights after phase modulation.
7. The system of claim 1, wherein, The heating electrode regulates the effective refractive index of the corresponding waveguide by applying a voltage based on the thermo-optic effect. The phase detection module comprises directional couplers respectively connected to the waveguides on which the two transmission lights after phase modulation are located, and an output combiner, a cross waveguide, and an output coupler. Each directional coupler is configured to extract the optical power of the two transmission lights after phase modulation according to a preset ratio, and obtain two sampling lights. The output combiner is configured to combine the two sampling lights through interference and obtain phase detection light. The cross waveguide is configured to guide the phase detection light to the output coupler. The output coupler is configured to output the phase detection light off-chip for phase detection.
8. The system of claim 1, wherein, The system has a core-shell structure, which includes a core layer and a cladding layer; wherein the core layer is made of silicon nitride and the cladding layer is made of silicon dioxide in the case of regulating the visible light waveband.
9. A nanowire waveguide point-diffraction light source based on the on-chip regulated point-diffraction interference system according to any one of claims 1 to 8, characterized in that, The transmission light propagates in the core layer of the nanowire waveguide, and the nanowire waveguide limits the transmission light field in the wavelength or subwavelength level based on the refractive index difference between the core layer and the cladding layer to realize light field localization, wherein the light field is diffracted to form a diffraction spherical wave meeting the preset requirements and having at least a specified numerical aperture when exiting from the end face.
10. An on-chip tuning method based on a nanowire waveguide point-diffraction light source, characterized in that, The method comprises the following steps: An external laser is coupled to the on-chip waveguide through the light injection module and output to two waveguides; The transmission light intensity of the two waveguides is independently adjusted through the intensity regulation module, and the two transmission lights after intensity modulation are output; The effective refractive index of the two waveguides where the two transmission lights after intensity modulation are located is regulated through the phase regulation module to realize the regulation of the phase difference of the two transmission lights after intensity modulation, and the two transmission lights after phase modulation are output; The two waveguides where the two transmission lights after phase modulation are located are respectively taken as nanowire waveguide point diffraction light sources through the light source interference module to realize the point diffraction of the two transmission lights after phase modulation when passing through the nanowire waveguide end face, and the interference fringes generated by the interference of the two point diffraction light waves are applied to the three-dimensional profile reconstruction of an object or the measurement of objective lens wave aberration; The two transmission lights after phase modulation are extracted for on-chip interference through the phase detection module, and the phase detection light is output for phase detection.