Optical phased array radiator

Abstract

The present invention relates to an optical phase array radiator comprising a silicon material optical waveguide having a fixed length, a plurality of unit optical radiators arranged in parallel, a cladding portion covering the unit optical radiators, and a plurality of electrodes arranged in parallel with the plurality of unit optical radiators on the cladding portion, wherein the plurality of electrodes are arranged in a vertical direction so as not to overlap with the plurality of unit optical radiators. According to the present invention, a beam radiated through the optical radiators can be efficiently steered vertically through the phase array.

Description

Technology Field

[0001] The present invention relates to an optical phased array radiator utilizing a thermo-optical effect based on an optical phased array (OPA). Background Technology

[0002] Radio Detection and Ranging (RADAR) technology, which utilizes electromagnetic waves to detect the location or shape of objects at a distance, has long been used in various fields. Recently, building upon this detection technology, Light Detection and Ranging (LiDAR) technology, which is more precise, faster, and miniaturized, is being developed. LiDAR technology, which utilizes light, is considered a core technology for major next-generation industries such as autonomous vehicles, wireless optical communication, and 3-D sensing.

[0003] Among the components constituting the above lidar, the light radiator for radiating the collimated beam in a desired direction is an important component. As referenced in FIG. 1, a typical structure of the light radiator is a structure in which a number of grating radiators (110) are arranged in parallel as basic units, and the horizontal direction of the collimated beam radiated from the grating radiator array can be controlled by adjusting the phase difference of the light (130) input to each grating radiator. At this time, the size of the horizontal field of view (horizontal radiation angle), which is the maximum steerable range, has the characteristic of being inversely proportional to the array spacing of each grating radiator array, and the maximum horizontal field of view (horizontal radiation angle) can be obtained when the array spacing is half the wavelength of the input light.

[0004] In addition, as shown in the following Equation 1, the grating optical radiator has a grating period and an effective refractive index (n). effThe vertical radiation angle of the radiation beam is determined according to the ) and, by using this, the temperature of the grating optical radiator can be adjusted to control the effective index, thereby controlling the vertical direction of the collimated beam being emitted.

[0005]

[0006] Joule heating is used to control the temperature, and the metal and high-concentration doping regions are used as conductors (120), and the Joule heating is controlled by using an intrinsic silicon region that forms a grid photoradiator array as a resistor.

[0007] With reference to FIG. 2 and FIG. 3, which is the AA' cross-section of FIG. 2, a grating light radiator (213) as a high-refractive-index silicon light waveguide (n=128, 256,...) is arranged, and a cladding portion (211) of low-refractive-index silica cladding is provided in a form that covers the grating light radiator (213).

[0008] An electrode structure for controlling the vertical radiation angle of a beam emitted from a grid light radiator is provided with a resistor capable of controlling the temperature of the grid structure, and includes an electrode (214) and a wire (216) to supply power to the resistor.

[0009] In order to obtain a temperature change of the grid photoradiator, a high-concentration doping region (215) is formed to supply power from the grid photoradiator.

[0010] With the resistance arrangement in such conventional technology, uniform temperature changes cannot be expected across the entire area of ​​the grid photoradiator array.

[0011] That is, the physical structure of the intrinsic silicon region (i region) and the non-uniform resistance cause a non-uniform temperature distribution, which leads to phase non-uniformity of the laser light and ultimately results in instability of the laser light as shown in Fig. 4.

[0012] The distance between these electrodes is determined by the overall width of the grating photoradiator, and the better the performance of the grating photoradiator, the longer the distance between the electrodes becomes.

[0013] However, as the overall area of ​​the photoradiator increases, the probability of resistance imbalance occurring due to reasons such as process errors increases. In addition, an increase in the distance between electrodes leads to an increase in the resistance of the grid photoradiator array, requiring the application of a higher voltage.

[0014] When heating the grating photoradiator by applying a higher voltage, temperature non-uniformity occurs due to resistance imbalance, causing the effective refractive index of each part to change. Consequently, this can affect the divergence angle collimated through the phase array and degrade beam performance.

[0015] In addition, the total amount of heat applied increases due to the application of higher voltage, and localized heating caused by resistance imbalance can affect the durability of the photoradiator and cause the photoradiator to break.

[0016] The matters described in the background technology above are intended to aid in understanding the background of the invention and may include matters that are not prior art already known to those skilled in the art to which this technology belongs. Prior art literature

[0017] Korean Patent Publication No. 10-1702436 The problem to be solved

[0018] The present invention has been devised to solve the aforementioned problems, and the purpose of the present invention is to provide an optical phase array radiator for efficiently vertically steering a beam radiated through an optical radiator via a phase array. means of solving the problem

[0019] An optical phase array radiator according to one aspect of the present invention is an optical waveguide made of silicon material having a certain length, comprising a plurality of unit optical radiators arranged in parallel, a cladding portion covering the unit optical radiators, and a plurality of electrodes arranged in parallel with the plurality of unit optical radiators on the cladding portion, wherein the plurality of electrodes are arranged in a vertical direction so as not to overlap with the plurality of unit optical radiators.

[0020] In addition, the plurality of electrodes are characterized by being arranged in a direction perpendicular to the plurality of unit light radiators.

[0021] In addition, it may further include doping regions formed in a number corresponding to a plurality of electrodes on the base portion of the lower portion of a plurality of unit light radiators, and wires connecting the plurality of electrodes and the plurality of doping regions, respectively.

[0022] In addition, the plurality of the above-mentioned doping portions are characterized by being arranged in a vertical direction so as not to overlap with the plurality of the above-mentioned unit light radiators.

[0023] Here, the cladding part is characterized as being a silica cladding having a lower refractive index than the unit light radiator.

[0024] In addition, the spacing of the plurality of the above-mentioned unit light radiators is the same, and each of the above-mentioned unit light radiators is characterized by having an uneven structure formed at equal intervals along the length direction.

[0025] Next, according to another aspect of the present invention, an optical phase array radiator comprises a plurality of unit optical radiators arranged in parallel, an optical waveguide made of silicon material having a constant length, a cladding portion covering the unit optical radiators, a first electrode spaced apart along the width direction of the cladding portion on one side of the upper surface of the cladding portion, and a second electrode spaced apart along the width direction of the cladding portion on the other side of the upper surface of the cladding portion opposite to the first electrode.

[0026] In addition, it may further include a plurality of doping regions formed in the base portion of the lower portion of the plurality of unit light radiators and arranged in a vertical direction so as not to overlap with the plurality of unit light radiators, and a wire connecting the plurality of doping regions to the first electrode or the second electrode, respectively.

[0027] In addition, the plurality of doping portions are characterized by being arranged between the plurality of unit light radiators.

[0028] In addition, the spacing of the plurality of the above-mentioned unit light radiators is the same, and each of the above-mentioned unit light radiators is characterized by having an uneven structure formed at equal intervals along the length direction.

[0029] Furthermore, each of the above-described unit light radiators is divided into an uneven structure region in which the uneven structure is formed and a non-uneven structure region in which the uneven structure is not formed, and is characterized by being tapered such that the width gradually decreases as it moves away from the uneven structure region.

[0030] And, each of the above-mentioned doping portions is divided into a first doping portion corresponding to an area corresponding to the uneven structure area and a second doping portion corresponding to an area corresponding to the non-uneven structure area, and is characterized by being tapered such that the width gradually increases as it moves away from the first doping portion.

[0031] In addition, the above wire is characterized by being connected to the second doping portion of a plurality of the above doping portions.

[0032] In addition, the above cladding part is characterized by being a silica cladding having a lower refractive index than the unit light radiator. Effects of the invention

[0033] According to the optical phase array radiator of the present invention, by placing a high-concentration doping region applied to a conventional optical radiator between each optical radiator, the doping region acts as an electrode and the grid optical radiator region acts as a resistor, thereby enabling heat to be applied evenly to all regions of the grid optical radiator.

[0034] In addition, by reducing the spacing between each photoradiator, a wide horizontal field of view is obtained, and the difficulties in processing high-concentration doping regions and metal wires connecting them to the chip surface caused by the reduced spacing can be resolved.

[0035] In addition, the grating light emitter can increase durability by preventing local temperature limits and exceeding allowable current due to increased spacing.

[0036] In addition, the vertical divergence angle of a beam radiated from a cross-sectional light-emitting phase array radiator, which is steered horizontally, can be adjusted while maintaining the horizontal steering direction.

[0037] In addition, by reducing the vertical divergence angle, it can improve vertical resolution in applications that detect objects using a radiation beam, and it also has the advantage of increasing the detection distance by reducing beam diffusion. Brief explanation of the drawing

[0038] FIGS. 1 to 3 illustrate a conventional grid light radiator. Figure 4 illustrates the difference in vertical radiation angles due to conventional heat. FIG. 5 illustrates a planar cross-section of an optical phase array radiator according to one embodiment of the present invention. Figure 6 shows the BB' cross-section of Figure 5. FIG. 7 illustrates a planar cross-section of an optical phase array radiator according to an application embodiment of the present invention. Figure 8 illustrates the CC' cross-section of Figure 7, and Figure 9 illustrates the DD' cross-section of Figure 7. Specific details for implementing the invention

[0039] In order to fully understand the present invention, the operational advantages of the present invention, and the objectives achieved by the implementation of the present invention, reference must be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described therein.

[0040] In describing preferred embodiments of the present invention, known technologies or repetitive descriptions that may unnecessarily obscure the essence of the invention will be shortened or omitted.

[0041] FIG. 5 illustrates a planar cross-section of an optical phase array radiator according to one embodiment of the present invention, and FIG. 6 illustrates the BB' cross-section of FIG. 5.

[0042] Hereinafter, an optical phase array radiator according to an embodiment of the present invention will be described with reference to FIGS. 5 and FIGS. 6.

[0043] An optical phase array radiator according to one embodiment of the present invention is implemented on an internal plane of a chip, comprising N unit optical radiators (313) having a constant length arranged in parallel, and the unit optical radiators (313) connected by a lower base portion (313-1) and a cladding portion (311) covering the unit optical radiators (313).

[0044] The unit light radiator (313) is an optical waveguide made of silicon material having a high refractive index, through which a phase-controlled beam is transmitted along the length direction.

[0045] The cladding portion (311) is a silica cladding having a low refractive index of silicon oxide (Si, O2), which allows the beam to be transmitted through a unit light radiator (313).

[0046] Each unit light radiator (313) has an uneven structure of different heights formed at equal intervals along the length direction.

[0047] Multiple unit light radiators (313) are arranged at regular intervals, and the smaller the interval, the larger the horizontal field of view (horizontal radiation angle) of the steering beam radiated through the light phase array radiator. Therefore, to obtain a wide horizontal field of view (horizontal radiation angle), the interval between the unit light radiators (313) can be smaller than the wavelength or half the wavelength.

[0048] In addition, in order to control the vertical radiation angle of the radiating steering beam, it is necessary to control the effective refractive index by controlling the temperature of the unit light radiator (313), and the present invention uniformly controls the temperature of each unit light radiator (313) to resolve phase imbalance and prevent the performance of the vertically steered radiation beam from deteriorating.

[0049] To this end, a plurality of electrodes (314) are formed on the cladding portion (311) parallel to the longitudinal direction of the unit light radiator (313) and arranged between the unit light radiators (313). That is, they are arranged so as not to overlap with the plurality of unit light radiators (313) in a vertical direction.

[0050] In addition, multiple high-concentration doping sections (315) are formed to uniformly control the temperature of the optical phase array radiator, and each corresponding electrode (314) and each doping section (315) are electrically connected by a wire (316).

[0051] The doping region (315) is formed on the base portion (313-1) on the side of each unit light radiator (313), including between the unit light radiators (313), and is arranged parallel to the unit light radiators (313) so that Joule heating in the intrinsic region (312) is controlled as a resistance.

[0052] Through this, temperature changes can be uniformly controlled in all unit light radiators (313), and the degradation of beam performance during vertical beam steering can be minimized compared to conventional methods.

[0053] Next, FIG. 7 illustrates a planar cross-section of an optical phase array radiator according to an application embodiment of the present invention, FIG. 8 illustrates the CC' cross-section of FIG. 7, and FIG. 9 illustrates the DD' cross-section of FIG. 7.

[0054] Hereinafter, an optical phase array radiator according to an application embodiment of the present invention will be described with reference to FIGS. 7 to 9.

[0055] An optical phase array radiator according to an application embodiment of the present invention comprises N unit optical radiators (413) having a constant length arranged in parallel on a base portion (413-3) and a cladding portion (411) covering the unit optical radiators (413).

[0056] The unit light radiator (413) is an optical waveguide made of silicon material having a high refractive index, through which a phase-controlled beam is transmitted along the length direction.

[0057] The cladding portion (411) is a silica cladding with a low refractive index, which allows the beam to be transmitted through the unit light emitter (413).

[0058] Each unit light radiator (413) has an uneven structure of different heights formed at equal intervals along the length direction.

[0059] Each light radiator (413) can be divided into an uneven structure area (413-1) and a non-uneven structure area (413-2) in which an uneven structure is formed. The width of the uneven structure area (413-1) is the same, but the width of the non-uneven structure area (413-2) has a tapered structure such that the width becomes smaller as it moves further away from the uneven structure area (413-1).

[0060] This is intended to resolve the issue where, when the spacing between light radiators is narrow for a wide horizontal radiation angle, the doping portion (415) and the wire (416) cannot be placed between the unit light radiators (413) due to process limitations. By modifying the light radiator (413), the electrode and the doping portion to be described later, the doping portion (415) and the wire (416) can be placed between the unit light radiators (413), thereby preventing the exceeding of the allowable current limit that may occur when connecting narrow widths.

[0061] Additionally, a plurality of electrodes are formed on the cladding portion (411). Unlike the previous embodiment, a first electrode (414-1) is formed on one side of the upper surface of the cladding portion (411) and spaced apart along the width direction of the cladding portion (411), and a second electrode (414-2) is formed on the other side of the upper surface of the cladding portion (411) and spaced apart along the width direction of the cladding portion (411) so as to face the first electrode (414-1). Each first electrode (414-1) and second electrode (414-2) is formed in a plurality, spaced apart along the width direction of the cladding portion (411).

[0062] In addition, multiple high-concentration doping sections (415) are formed to uniformly control the temperature of the optical phase array radiator, and each corresponding electrode (414) and each doping section (415) are electrically connected by a wire (416).

[0063] The doping region (415) is formed on the side base portion (413-3) of each unit light radiator (413), including between the unit light radiators (313), so that Joule heating is controlled in the intrinsic region (312) as a resistance.

[0064] This allows for uniform temperature control in all unit light radiators (413).

[0065] Accordingly, the position of the wire (416) connecting the doping portion (415) and the electrodes (414-1, 414-2) on the chip surface is placed outside the range of the optical phase array radiator.

[0066] Meanwhile, the doping portion (415) can be divided into a doping portion connected to the first electrode (414-1) and a doping portion connected to the second electrode (414-2).

[0067] And, each doping portion (415) can be divided into a first doping portion (415-1) corresponding to an area corresponding to an uneven structure region (413-1) of the unit optical radiator (413) in the longitudinal direction and a second doping portion (415-2) corresponding to an area corresponding to a non-uneven structure region (413-2), and the width of the first doping portion (415-1) is the same, but the width of the second doping portion (415-2) has a tapered structure such that the width gradually increases as it moves away from the first doping portion (415-1) and closer to a position corresponding to the electrode (414-1, 414-2).

[0068] Therefore, the wire (416) can be connected to a second doping section (415-2) which is wider than the first doping section (415-1), thereby allowing for a wider wire to be connected.

[0069] According to this application example, when the spacing between unit light radiators is narrow to improve the performance of the optical phase array radiator, the problem of not being able to place the doping part (415) and the wire (416) between the unit light radiators (413) can be overcome by overcoming process limitations, and the problem of exceeding the allowable current limit that may occur when connecting narrow widths due to the tapered structure can be prevented.

[0070] Although the present invention has been described above with reference to the illustrated drawings, it is obvious to those skilled in the art that it is not limited to the described embodiments and can be modified and varied in various ways without departing from the spirit and scope of the invention. Accordingly, such modifications or variations should be deemed to fall within the scope of the claims of the present invention, and the scope of rights of the present invention should be interpreted based on the appended claims. Explanation of the symbols

[0071] 311, 411: Cladding section 312, 412: True domain 313, 413: Unit optical radiator 313-1, 413-3 : Base section 413-1: Uneven structure area 413-2: Non-uneven structure area 314 : Electrode 414-1 : First electrode 414-2 : Second electrode 315, 415 : Doping Department 415-1: 1st Doping Department 415-2: 2nd Doping Department 316, 416 : Dosun

Claims

Claim 1 delete Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 An optical phase array radiator comprising: a plurality of unit optical radiators arranged in parallel, the optical waveguide made of silicon material having a fixed length; a cladding portion covering the unit optical radiators; a first electrode spaced apart along the width direction of the cladding portion on one side of the upper surface of the cladding portion; and a second electrode spaced apart along the width direction of the cladding portion on the other side of the upper surface of the cladding portion opposite to the first electrode, wherein each of the unit optical radiators is divided into an uneven structure region in which an uneven structure is formed and a non-uneven structure region in which the uneven structure is not formed, and is tapered such that the width gradually decreases from the non-uneven structure region toward the first electrode. Claim 8 An optical phase array radiator according to claim 7, comprising: a plurality of doping regions formed in a base portion of the lower portion of a plurality of unit light radiators and arranged in a vertical direction so as not to overlap with the plurality of unit light radiators; and a wire connecting the plurality of doping regions to the first electrode or the second electrode, respectively. Claim 9 An optical phase array radiator according to claim 8, characterized in that a plurality of the doping portions are arranged between a plurality of the unit optical radiators. Claim 10 An optical phase array radiator according to claim 9, characterized in that the spacing of a plurality of the unit light radiators is the same, and the uneven structure is formed at equal intervals along the length direction in each of the unit light radiators. Claim 11 delete Claim 12 An optical phase array radiator according to claim 9, wherein each of the doping portions is divided into a first doping portion corresponding to a region corresponding to the uneven structure region and a second doping portion corresponding to a region corresponding to the non-uneven structure region, and is tapered such that the width gradually increases as it moves away from the first doping portion. Claim 13 An optical phase array radiator according to claim 12, characterized in that the wire is connected to the second doping portion of a plurality of doping portions. Claim 14 An optical phase array radiator according to claim 7, characterized in that the cladding portion is a silica cladding having a lower refractive index than the unit optical radiator.

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