A switch-type two-dimensional beam scanner

Abstract

This invention discloses a switch-type two-dimensional beam scanner, comprising: a laser for generating an external beam; an optical path selection device composed of multiple Mach-Zehnder interferometers integrated in a two-dimensional topology, wherein the input end of each Mach-Zehnder interferometer is used to receive the beam from the laser, or is cross-connected to one output end of another Mach-Zehnder interferometer; a grating coupler connected to another output end of the Mach-Zehnder interferometer, used to receive the beam output by the Mach-Zehnder interferometer and output the beam to the outside, thereby realizing two-dimensional beam scanning; by adjusting the Mach-Zehnder interferometer, the phase of the beam passing through the Mach-Zehnder interferometer is changed, thereby changing the beam path and causing the beam to be output to the outside from a designated grating coupler, thereby achieving the purpose of controlling two-dimensional beam scanning. This scanner has low adjustment complexity, simple structure, and good scanning effect.

Description

Technical Field

[0001] This invention belongs to the field of beam scanning, and specifically relates to a switch-type two-dimensional beam scanner. Background Technology

[0002] In recent years, with the continuous development of drones, autonomous driving, and robotic vacuum cleaners, machine control has gradually shifted from initial remote control to the desire for fully autonomous control, freeing up human hands, eyes, and brains. To achieve full automation, efficient sensors are essential, with beam scanners being a key component. A beam scanner is a device that rapidly switches the direction or continuously scans a beam of light within a defined field of view, operating in the visible light or infrared bands used for communication. The laser emitted by a beam scanner has a small divergence angle and a narrow spot size. This high-speed scanning beam is well-suited for target locking, information transmission, and distance measurement, thus playing a crucial role in numerous application areas.

[0003] There are many implementation schemes for beam scanners, but they all have disadvantages. For example, mechanical optical scanning systems, which shape the beam through a lens group and rotate the lens group by a mechanical structure to achieve beam scanning, are often large in size, prone to wear and tear, thus reducing their service life, and are also expensive. In practical applications such as autonomous vehicle systems, they are extremely susceptible to vibration, which can lead to performance degradation.

[0004] For example, to overcome the bulky nature of the aforementioned mechanical optical scanning systems, the entire mechanical structure is integrated onto a chip. The movement of the micromechanical structure is controlled using electric fields or other methods to achieve beam scanning via a microelectromechanical system (MEMS). Specifically, a beam scanner based on an MEMS integrates a micromirror whose deflection angle can be controlled by an electric field onto the chip. Adjusting the electric field changes the deflection angle of the micromirror, thereby altering the angle between the incident and emitted light. While integration technology significantly reduces the system size, it remains susceptible to jitter and limitations imposed by the micromirror's aperture and angle. Furthermore, to eliminate the inevitable jitter limitations of mechanical structures, liquid crystal spatial light phase modulators have been developed to achieve beam scanning. Unfortunately, their phase modulation rate is on the order of milliseconds, insufficient for the microsecond to nanosecond speeds required for high-speed real-time imaging.

[0005] With the rapid development and continuous maturation of silicon-based photonic integration technology, beam scanners have found a novel and highly promising solution. Silicon-based photonic integration technology integrates various optical components, such as gratings, waveguides, and phase modulators, onto a single chip. The integrated devices can achieve sub-micron dimensions. Functions that previously required large, separate optical components in sets can now be realized within a silicon optoelectronic chip smaller than a coin, while maintaining performance and reducing cost and size. Furthermore, the modulation rate of on-chip phase modulators on silicon optoelectronic chips can reach GHz, providing strong support for high-speed on-chip beam adjustment.

[0006] Switched beam scanners control the direction of light emission by directing light through different paths, exhibiting clear controllability and directionality. Silicon-based focal plane array switched beam scanners, implemented using silicon photonics integration technology, can perform on-chip gating and off-chip scanning of the beam. Combining the advantages of switched beam scanners and silicon photonics integration technology, they offer smaller size, are all-solid-state with no mechanical structure, have high scanning speed, and their optical path gating is entirely controllable by a pure circuit system. Furthermore, and most importantly for commercialization, the mature chip manufacturing industry has led to a continuous reduction in the cost per chip after mass production. These advantages make silicon-based focal plane array switched beam scanners highly promising in applications such as 3D image shaping, free-space optical communication, and autonomous driving. Therefore, silicon-based focal plane array switched beam scanners are currently attracting significant research attention.

[0007] Currently, most common switch-type beam scanners rely on wavelength adjustment to achieve two-dimensional beam scanning, which places high demands on the laser source. Furthermore, the number of switching units is generally equal to the number of output units N, with a minimum of log2N, resulting in high control complexity and high power consumption. In addition, their complex structure makes them unsuitable for widespread application. Summary of the Invention

[0008] This invention provides a switch-type two-dimensional beam scanner, which has low control complexity, simple structure, and good scanning effect.

[0009] A specific embodiment of the present invention provides a switch-type two-dimensional beam scanner, comprising:

[0010] A laser used to generate an external light beam;

[0011] An optical path selection device, which consists of multiple Mach-Zehnder interferometers integrated in a two-dimensional topology, wherein the input end of the Mach-Zehnder interferometer is used to receive a beam from a laser, or is cross-connected to one output end of another Mach-Zehnder interferometer;

[0012] A grating coupler is connected to another output end of a Mach-Zehnder interferometer to receive the beam output by the Mach-Zehnder interferometer and output the beam to the outside, thereby realizing two-dimensional beam scanning.

[0013] By adjusting the Mach-Zehnder interferometer, the phase of the beam passing through the interferometer is changed, thereby altering the beam path and causing the beam to be output to the outside world from a designated grating coupler, thus achieving the purpose of controlling two-dimensional beam scanning.

[0014] This invention modulates the beam path by adjusting a Mach-Zehnder interferometer, enabling the internal beam to be output to the outside through a designated grating coupler along a designed path. Since the Mach-Zehnder interferometers provided by this invention form a two-dimensional topological structure through vertical cross-connection, this invention requires at most two adjustments to enable the beam to be output from the set position to the outside. Furthermore, the wavelength of the beam does not need to be adjusted during the adjustment process, making the adjustment relatively simple and the structure relatively simple as well.

[0015] Since the output of the Mach-Zehnder interferometer is connected to the grating coupler, and the Mach-Zehnder interferometers form a two-dimensional topology, the grating coupler is arranged in a two-dimensional array, which can easily realize two-dimensional beam output, thereby enabling efficient two-dimensional beam scanning.

[0016] Furthermore, the plurality of Mach-Zehnder interferometers are arranged in an array, including a beam-receiving Mach-Zehnder interferometer, a transition Mach-Zehnder interferometer, an intermediate Mach-Zehnder interferometer, and a boundary Mach-Zehnder interferometer, wherein:

[0017] The receiving beam Mach-Zehnder interferometer is located at the corner of the array and is used to receive the beam from the laser. One output of the receiving beam Mach-Zehnder interferometer is cross-connected to the input of the intermediate Mach-Zehnder interferometer, and the other output is cross-connected to the input of the transition Mach-Zehnder interferometer.

[0018] The output of the transition Mach-Zehnder interferometer is cross-connected to the input of different intermediate Mach-Zehnder interferometers.

[0019] One output of the intermediate Mach-Zehnder interferometer is cross-connected to the input of other intermediate Mach-Zehnder interferometers, or cross-connected to the input of the boundary Mach-Zehnder interferometer, and the remaining output is connected to the grating coupler.

[0020] The boundary Mach-Zehnder interferometer is located at the boundary of the array, and the output of the boundary Mach-Zehnder interferometer is connected to a grating coupler.

[0021] Furthermore, the receiving beam Mach-Zehnder interferometer, the transition Mach-Zehnder interferometer, the intermediate Mach-Zehnder interferometer, and the boundary Mach-Zehnder interferometer all have the same structure.

[0022] This invention achieves simple control by rationally arranging the Mach-Zehnder interferometer, which allows the beam to be emitted from the desired position in the two-dimensional array with at most two adjustments.

[0023] Furthermore, the Mach-Zehnder interferometer includes a first beam splitter, a phase adjustment device, and a second beam splitter, wherein:

[0024] The first beam splitter is used to divide the received beam into equal parts and send the split beams to the straight waveguide and the phase modulation device respectively.

[0025] The phase adjustment device is used to adjust the phase of the evenly split beam as needed;

[0026] The second beam splitter is used to interfere with the beam output from the straight waveguide and the phase-modulated beam to achieve destructive or constructive phase, thereby realizing the control of the optical path.

[0027] Furthermore, the first beam splitter is a multimode interferometer, a waveguide coupler, or a Y-branch; the second beam splitter is a multimode interferometer, a waveguide coupler, or a Y-branch.

[0028] Furthermore, the phase modulation device includes a phase-shifting waveguide and an integrated electronic control system, wherein the system is used to conduct electricity or heat to the phase-shifting waveguide to change the refractive index of the phase-shifting waveguide in order to change the phase of the light beam.

[0029] Furthermore, the integrated electronic control system is programmed to apply an electric field to the phase-shifting waveguide, thereby modulating the beam phase through the electro-optic effect.

[0030] Furthermore, the integrated electronic control system is controlled by a program to heat the resistor by voltage and then transfer heat to the phase-shift waveguide, thereby controlling the beam phase through the thermo-optic effect.

[0031] Furthermore, the switch-type two-dimensional beam scanner provided by the present invention is made of silicon, silicon nitride, or lithium niobate.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] (1) By changing the connection topology of the on-chip Mach-Zehnder interferometer, the present invention enables two-dimensional selection and scanning of the beam through a single wavelength, which greatly reduces the requirements for the laser source.

[0034] (2) By changing the connection topology of the on-chip Mach-Zehnder interferometer, the present invention enables the maximum number of control units to be selected as the switching unit to be 2, thereby controlling all units and greatly reducing the complexity and power consumption of control.

[0035] (3) The present invention implements the function with a simpler and more basic design, and based on the above advantages, it reduces the difficulty of large-scale application. Attached Figure Description

[0036] Figure 1 A schematic diagram of a switch-type two-dimensional beam scanner provided in a specific embodiment of the present invention;

[0037] Figure 2 A schematic diagram of a Mach-Zehnder interferometer provided for a specific embodiment of the present invention;

[0038] In the figure, 1-laser, 2-optical path selection device, 21-receiving beam Mach-Zehnder interferometer, 22-transition Mach-Zehnder interferometer, 23-intermediate Mach-Zehnder interferometer, 24-boundary Mach-Zehnder interferometer, 3-grating coupler, I1-first input terminal, I1-second input terminal, O1-first output terminal, O2-second output terminal, 2a-first beam splitter, 2b-first S-bend waveguide, 2c-straight waveguide, 2d-phase adjustment device, 2f-second S-bend waveguide, 2g-second beam splitter. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0040] A specific embodiment of the present invention provides a switch-type two-dimensional beam scanner, such as... Figure 1As shown, the device includes a laser 1, an optical path selection device 2, and a grating coupler 3 arranged along the optical path. A beam is emitted from the laser 1, the optical path selection device 2 receives the beam, and through phase modulation, the beam is directed to exit at a designated grating coupler 3 along a set optical path, thereby achieving two-dimensional beam scanning. The optical path selection device 2 provided in this embodiment is composed of multiple Mach-Zehnder interferometers integrated into a two-dimensional topology. Since the Mach-Zehnder interferometers themselves can modulate the phase of the beam to change the optical path, under the topology provided in this embodiment, the beam can be emitted from a designated position with a maximum of two modulations.

[0041] In one specific embodiment, the plurality of Mach-Zehnder interferometers provided by the present invention are arranged in an array, including a beam-receiving Mach-Zehnder interferometer 21, a transition Mach-Zehnder interferometer 22, an intermediate Mach-Zehnder interferometer 23, and a boundary Mach-Zehnder interferometer 24. Figure 1 ,in:

[0042] The receiving beam Mach-Zehnder interferometer 21 provided in this embodiment is located at the corner of the array and is used to receive the beam from the laser 1. One output end of the receiving beam Mach-Zehnder interferometer 21 is cross-connected to the input end of the intermediate Mach-Zehnder interferometer 23, and the other output end is cross-connected to the input end of the transition Mach-Zehnder interferometer 22.

[0043] The output of the transition Mach-Zehnder interferometer 22 provided in this embodiment is cross-connected to the input of different intermediate Mach-Zehnder interferometers 23.

[0044] In this embodiment, one output terminal of the intermediate Mach-Zehnder interferometer 23 is cross-connected with the input terminals of other intermediate Mach-Zehnder interferometers 23, or cross-connected with the input terminal of the boundary Mach-Zehnder interferometer 24, and the remaining output terminal is connected to the grating coupler 3.

[0045] The boundary Mach-Zehnder interferometer 24 provided in this embodiment is located at the boundary of the array, and the output terminals of the boundary Mach-Zehnder interferometer 24 are all connected to the grating coupler 3.

[0046] This invention provides a specific embodiment of the use of the switch-type two-dimensional beam scanner. It is foreseeable that there are multiple uses for the switch-type two-dimensional beam scanner provided in this embodiment, and it is not limited to the two examples provided here. Figure 1 As shown, this includes: when the phase adjustment device 2d of the receiving beam Mach-Zehnder interferometer 21 is not controlled, i.e. Figure 1 of When the position is not adjusted, the beam can be drawn from The grating coupler 3 at the location emits to the outside.

[0047] When the phase adjustment device 2d of the receiving beam Mach-Zehnder interferometer 21 is controlled, i.e. Figure 1 of When the position is adjusted, the beam can be from The grating coupler 3 at the location emits to the outside.

[0048] When the phase adjustment device 2d of the receiving beam Mach-Zehnder interferometer 21 and the intermediate Mach-Zehnder interferometer 23 is controlled, i.e. Figure 1 of and When the position is adjusted, the beam can be from The grating coupler 3 at the location emits to the outside.

[0049] As can be seen from the above control, the switch-type two-dimensional beam scanner provided by the present invention can achieve the beam to be emitted from the specified grating coupler 3 to the outside in a relatively simple way, with at most two control adjustments.

[0050] The receiving beam Mach-Zehnder interferometer, transition Mach-Zehnder interferometer, intermediate Mach-Zehnder interferometer, and boundary Mach-Zehnder interferometer provided in the specific embodiments of the present invention all have the same structure.

[0051] The Mach-Zehnder interferometer provided in a specific embodiment of the present invention includes a first input terminal I1, a second input terminal I1, a first output terminal O1, a second output terminal O2, a first beam splitter 2a, a first S-bend waveguide 2b, a straight waveguide 2c, a phase adjustment device 2d, a second S-bend waveguide 2f, and a second beam splitter 2g, wherein both the first beam splitter 2a and the second beam splitter 2g are 50:50 beam splitters.

[0052] The first beam splitter 2a provided in the specific embodiment of the present invention is used to divide the beam output from the first input terminal I1 into equal beams, and send the equalized beams to the straight waveguide 2c and the phase modulation device 2d respectively through the first S-curved waveguide 2b;

[0053] The phase modulation device 2d provided in the specific embodiment of the present invention is used to adjust the phase of the beam after it is evenly split as needed, and to send the phase-modulated beam to the second beam splitter 2g through the second S-bend waveguide 2f.

[0054] The second beam splitter 2g is used to interfere with the beam output from the straight waveguide 2c and the phase-modulated beam to achieve destructive or constructive interference, thereby realizing the control of the optical path and outputting from the first output terminal O1 or the second output terminal O2.

[0055] The phase modulation device 2d provided in a specific embodiment of the present invention includes a phase-shifting waveguide and an integrated electronic control system. The integrated electronic control system is connected to the phase-shifting waveguide and is used to conduct electricity or heat to the phase-shifting waveguide to change the refractive index of the phase-shifting waveguide and thus change the phase of the light beam.

[0056] The integrated electronic control system provided in this specific embodiment of the invention is used to apply an electric field to the phase-shifting waveguide through program control, thereby modulating the beam phase through the electro-optic effect. The integrated electronic control system is also used to heat a resistor via voltage to transfer heat into the phase-shifting waveguide, thereby modulating the beam phase through the thermo-optic effect.

[0057] In a specific embodiment of the present invention, the first beam splitter is a multimode interferometer, a waveguide coupler, or a Y-branch; the second beam splitter is a multimode interferometer, a waveguide coupler, or a Y-branch.

[0058] The switch-type two-dimensional beam scanner provided by this invention is made of silicon, silicon nitride, or lithium niobate.

[0059] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A switch-type two-dimensional beam scanner, characterized in that, include: A laser used to generate an external light beam; An optical path selection device, which consists of multiple Mach-Zehnder interferometers integrated in a two-dimensional topology, wherein the input end of the Mach-Zehnder interferometer is used to receive a beam from a laser, or is cross-connected to one output end of another Mach-Zehnder interferometer; A grating coupler is connected to another output end of a Mach-Zehnder interferometer to receive the beam output by the Mach-Zehnder interferometer and output the beam to the outside, thereby realizing two-dimensional beam scanning. By adjusting the Mach-Zehnder interferometer, the phase of the beam passing through the interferometer is changed, thereby altering the beam path and causing the beam to be output to the outside world from a designated grating coupler, thus achieving the purpose of controlling two-dimensional beam scanning.

2. The switch-type two-dimensional beam scanner according to claim 1, characterized in that, The plurality of Mach-Zehnder interferometers are arranged in an array, including a beam-receiving Mach-Zehnder interferometer, a transition Mach-Zehnder interferometer, an intermediate Mach-Zehnder interferometer, and a boundary Mach-Zehnder interferometer, wherein: The receiving beam Mach-Zehnder interferometer is located at the corner of the array and is used to receive the beam from the laser. One output of the receiving beam Mach-Zehnder interferometer is cross-connected to the input of the intermediate Mach-Zehnder interferometer, and the other output is cross-connected to the input of the transition Mach-Zehnder interferometer. The output of the transition Mach-Zehnder interferometer is cross-connected to the input of different intermediate Mach-Zehnder interferometers. One output of the intermediate Mach-Zehnder interferometer is cross-connected to the input of other intermediate Mach-Zehnder interferometers, or cross-connected to the input of the boundary Mach-Zehnder interferometer, and the remaining output is connected to the grating coupler. The boundary Mach-Zehnder interferometer is located at the boundary of the array, and the output of the boundary Mach-Zehnder interferometer is connected to a grating coupler.

3. The switch-type two-dimensional beam scanner according to claim 2, characterized in that, The receiving beam Mach-Zehnder interferometer, the transition Mach-Zehnder interferometer, the intermediate Mach-Zehnder interferometer, and the boundary Mach-Zehnder interferometer all have the same structure.

4. The switch-type two-dimensional beam scanner according to claim 1, characterized in that, The Mach-Zehnder interferometer includes a first beam splitter, a phase adjustment device, and a second beam splitter, wherein: The first beam splitter is used to divide the received beam into equal parts and send the split beams to the straight waveguide and the phase modulation device respectively. The phase adjustment device is used to adjust the phase of the evenly split beam as needed; The second beam splitter is used to interfere with the beam output from the straight waveguide and the phase-modulated beam to achieve destructive or constructive phase, thereby realizing the control of the optical path.

5. The switch-type two-dimensional beam scanner according to claim 4, characterized in that, The first beam splitter is a multimode interferometer, a waveguide coupler, or a Y-branch; the second beam splitter is a multimode interferometer, a waveguide coupler, or a Y-branch.

6. The switch-type two-dimensional beam scanner according to claim 4, characterized in that, The phase modulation device includes a phase-shifting waveguide and an integrated electronic control system. The integrated electronic control system is connected to the phase-shifting waveguide and is used to conduct electricity or heat to the phase-shifting waveguide to change the refractive index of the phase-shifting waveguide and thus change the phase of the light beam.

7. The switch-type two-dimensional beam scanner according to claim 6, characterized in that, The integrated electronic control system is programmed to apply an electric field to the phase-shifting waveguide, thereby modulating the beam phase through the electro-optic effect.

8. The switch-type two-dimensional beam scanner according to claim 6, characterized in that, The integrated electronic control system is controlled by a program to heat the resistor by voltage and then transfer heat to the phase-shift waveguide, thereby controlling the phase of the beam through the thermo-optic effect.

9. The switch-type two-dimensional beam scanner according to claim 1, characterized in that, The materials used in the switch-type two-dimensional beam scanner are silicon, silicon nitride, or lithium niobate.

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