Material sensing device, optical integrated circuit, and material sensing method

Abstract

The present invention provides a material sensing device, an optical integrated circuit, and a material sensing method that can perform material sensing with high accuracy. [Solution] The material sensing device 1 comprises an optical integrated circuit 10 having a substrate 11, a ring resonator 5 formed on the substrate 11 having a first waveguide 51, a ring waveguide 52 provided with a plurality of receptors RP to which material S is coupled, and a second waveguide 53, an optical separation unit 21 that receives measurement light L traveling through the first waveguide 51 and separates the measurement light L into a first light L1 and a second light L2 at a predetermined separation ratio, wherein the separation ratio changes monotonically in a predetermined wavelength range, an optical detection unit that detects at least one of the first light L1 and the second light L2, and a calculation unit 9b that acquires information on the centroid wavelength of the measurement light L based at least on the detection result of the optical detection unit and acquires information on the amount of material S coupled to the plurality of receptors RP based on the information on the centroid wavelength.

Description

[Technical Field]

[0001] The present invention relates to a material sensing device, an optical integrated circuit, and a material sensing method. [Background technology]

[0002] For example, Patent Document 1 describes a material sensing device using a ring resonator (Figure 15). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-104300 [Overview of the project] [Problems that the invention aims to solve]

[0004] In the substance sensing device described in Patent Document 1, an antibody is placed in a ring resonator, and the antibody captures the antigen. During use, light at the ring resonator's resonant peak wavelength is input to the ring resonator from a variable wavelength light source. When the antibody captures the antigen, the effective refractive index of the light transmitted through the ring resonator changes, causing a shift in the resonant peak wavelength according to the antigen concentration. At that time, the light output from the ring resonator is attenuated due to the mismatch between the wavelength of the fixed light source and the resonant peak wavelength of the ring resonator. Therefore, by linking the amount of fluctuation in output power with the amount of fluctuation in the refractive index of the ring resonator, it is possible to estimate the amount of change in refractive index. Since the sample has a unique refractive index, the detected substance can be identified or its concentration can be determined from the shift in the resonant peak wavelength.

[0005] In order to accurately determine the concentration of substances such as antigens, it is necessary to measure the wavelength shift on the order of a few picometers. However, methods based on fluctuations in optical output power, such as the method described in Patent Document 1, are susceptible to changes in the shape of the wavelength spectrum of the output light, or changes in the shape or intensity of the wavelength spectrum of the input light, making it difficult to accurately measure the wavelength shift.

[0006] Therefore, the present invention aims to provide a material sensing device, an optical integrated circuit, and a material sensing method that can perform material sensing with high accuracy. [Means for solving the problem]

[0007] The material sensing apparatus of the present invention comprises: [1] an optical integrated circuit having a substrate; a ring resonator formed on the substrate, the ring resonator having a first waveguide into which measurement light having a predetermined wavelength is input; a ring waveguide provided with a plurality of receptors to which material is coupled and optically connected to the first waveguide; and a second waveguide optically connected to the ring waveguide, the ring resonator guiding the measurement light having a resonant wavelength corresponding to the resonator length of the ring waveguide from the first waveguide through the ring waveguide to the second waveguide; and the first waveguide A material sensing device comprising: an optical separation unit that receives measurement light, or the measurement light traveling through the second waveguide, and separates the measurement light into first light and second light at a predetermined separation ratio, wherein the separation ratio changes monotonically in a predetermined wavelength range; an optical detection unit that detects at least one of the first light and the second light; and a calculation unit that acquires information regarding the centroid wavelength of the measurement light based at least on the detection result of the optical detection unit, and acquires information regarding the amount of the substance coupled to the plurality of receptors based on the acquired information regarding the centroid wavelength.

[0008] This material sensing device receives measurement light traveling through a first waveguide or measurement light traveling through a second waveguide, and includes an optical separation unit that separates the measurement light into first and second light at a predetermined separation ratio. This separation ratio changes monotonically in a predetermined wavelength range. At least one of the first and second light is detected by an optical detection unit, and information regarding the centroid wavelength of the measurement light is obtained based at least on the detection result of the optical detection unit. Information regarding the amount of substance bound to multiple receptors is then obtained based on the obtained information regarding the centroid wavelength. As a result, information regarding the centroid wavelength of the measurement light can be obtained with high wavelength resolution, and information regarding the amount of substance bound to receptors can be obtained with high accuracy. Therefore, this material sensing device enables accurate material sensing.

[0009] The material sensing apparatus of the present invention may also be [2] "the material sensing apparatus according to [1], further comprising a wavelength filter section provided in the first waveguide, which transmits light in a transmission range including at least a part of the predetermined wavelength range while blocking light outside the transmission range." In this case, it is possible to suppress the input of light having a peak in a wavelength range other than the predetermined wavelength range in which the separation rate changes monotonically to the optical separation section.

[0010] The material sensing apparatus of the present invention may also be the material sensing apparatus according to [1] or [2], wherein the optical separation unit is a wavelength separation coupler formed on the substrate. In this case, the optical separation unit can be realized using a wavelength separation coupler formed on the substrate.

[0011] The material sensing apparatus of the present invention may also be the material sensing apparatus described in [3], wherein the wavelength separation coupler is a wavelength division multiplexing coupler. In this case, the optical separation unit can be realized using a wavelength division multiplexing (WDM) coupler.

[0012] The material sensing apparatus of the present invention may also be the material sensing apparatus according to [1] or [2], wherein the optical separation unit is an optical filter disposed outside the substrate. In this case, the optical separation unit can be realized using an optical filter disposed outside the substrate.

[0013] The material sensing apparatus of the present invention may also be [6] "a material sensing apparatus according to any one of [1] to [5], wherein the light detection unit comprises a first detector for detecting the first light and a second detector for detecting the second light." In this case, information regarding the centroid wavelength of the measurement light can be obtained based on the detection results of both the first and second light.

[0014] The material sensing device of the present invention may also be [7] "the material sensing device according to any one of [1] to [6], wherein the ring resonator has a plurality of ring waveguides, and the plurality of ring waveguides are optically connected in series." In this case, the interval between the resonant wavelengths in the ring resonator can be widened, and as a result, the design freedom of the optical separation unit can be improved.

[0015] The optical integrated circuit of the present invention may also be [8] "a material sensing device according to any one of [1] to [7], wherein the light detection unit is formed on the substrate." In this case, the device can be miniaturized.

[0016] The optical integrated circuit of the present invention may also be a material sensing device according to any one of [1] to [8], further comprising a light source that outputs the measurement light, wherein the light source is formed on the substrate. In this case, the device can be miniaturized.

[0017] The optical integrated circuit of the present invention may also be

[10] "a material sensing device according to any of [1] to [9], wherein the ring resonator has a plurality of ring waveguides, the plurality of ring waveguides include a first ring waveguide and a second ring waveguide, and the material coupled to the plurality of receptors of the first ring waveguide is different from the material coupled to the plurality of receptors of the second ring waveguide." In this case, sensing of multiple types of materials can be performed.

[0018] The optical integrated circuit of the present invention is

[11] "an optical integrated circuit comprising: a substrate; a ring resonator formed on the substrate, the ring resonator having a first waveguide into which measurement light having a predetermined wavelength is input; a ring waveguide having a plurality of receptors into which a material is coupled and which is optically connected to the first waveguide; and a second waveguide optically connected to the ring waveguide, the ring resonator guiding the measurement light having a resonant wavelength corresponding to the resonator length of the ring waveguide from the first waveguide through the ring waveguide to the second waveguide; and an optical separation unit formed on the substrate, which receives the measurement light traveling through the first waveguide or the measurement light traveling through the second waveguide, and separates the measurement light into first light and second light at a predetermined separation ratio, the separation ratio changing monotonically in a predetermined wavelength range."

[0019] This optical integrated circuit receives measurement light traveling through a first waveguide or measurement light traveling through a second waveguide, and includes an optical separation unit that separates the measurement light into first and second light at a predetermined separation ratio. This separation ratio changes monotonically in a predetermined wavelength range. When performing material sensing using this optical integrated circuit, at least one of the first and second light is detected, information regarding the centroid wavelength of the measurement light is obtained based at least on the detection result, and information regarding the amount of substance bound to multiple receptors is obtained based on the obtained information regarding the centroid wavelength. As a result, information regarding the centroid wavelength of the measurement light can be obtained with high wavelength resolution, and information regarding the amount of substance bound to the receptors can be obtained with high accuracy. Therefore, material sensing can be performed with high accuracy using this optical integrated circuit.

[0020] The substance sensing method of the present invention is "

[12] A substance sensing method using a substance sensing device, wherein the substance sensing device includes an optical integrated circuit having a substrate and a ring resonator formed on the substrate. The ring resonator includes a first waveguide into which measurement light having a predetermined wavelength is input, a plurality of receptors to which a substance binds, a ring waveguide provided with the plurality of receptors and optically connected to the first waveguide, and a second waveguide optically connected to the ring waveguide. The ring resonator guides the measurement light having a resonance wavelength corresponding to the resonator length of the ring waveguide from the first waveguide through the ring waveguide to the second waveguide. The substance sensing method includes an optical detection step of inputting the measurement light into the first waveguide and detecting at least one of the first light and the second light, and an arithmetic step of obtaining information on the center wavelength of the measurement light based on at least the detection result of the optical detection step and obtaining information on the amount of the substance bound to the plurality of receptors based on the obtained information on the center wavelength."

[0021] In this substance sensing method, a substance sensing device including an optical separation unit that inputs measurement light traveling through the first waveguide or the second waveguide and separates the measurement light into first light and second light at a predetermined separation ratio is used. The separation ratio monotonically changes in a predetermined wavelength range. Then, at least one of the first light and the second light is detected, information on the center wavelength of the measurement light is obtained based on at least the detection result, and information on the amount of the substance bound to the plurality of receptors is obtained based on the obtained information on the center wavelength. As a result, information on the center wavelength of the measurement light can be obtained with high wavelength resolution, and information on the amount of the substance bound to the receptor can be accurately obtained. Therefore, according to this substance sensing method, substance sensing can be accurately performed.

Advantages of the Invention

[0022] According to the present invention, it is possible to provide a substance sensing device, an optical integrated circuit, and a substance sensing method capable of performing accurate substance sensing.

Brief Description of the Drawings

[0023] [Figure 1] It is a configuration diagram of the substance sensing device of the embodiment. [Figure 2] (a) is a diagram showing light input to the input unit, (b) is a diagram showing light output from the wavelength filter unit, and (c) is a diagram showing light transferred to the ring resonator. [Figure 3] (a) is a diagram showing the wavelength detection unit of the first example, (b) is a diagram showing the wavelength detection unit of the second example, and (c) is a diagram showing the wavelength detection unit of the third example. [Figure 4] It is a diagram showing an example of the transmittance of the optical separation unit. [Figure 5] It is a diagram for explaining a method of calculating the centroid wavelength. [Figure 6] (a) is a diagram showing the reference state, (b) is a diagram showing the case where the centroid wavelength is deviated from the reference state, and (c) is a diagram showing another case where the centroid wavelength is deviated from the reference state. [Figure 7] (a), (b) and (c) are diagrams showing the states corresponding to FIGS. 6(a), 6(b) and 6(c). [Figure 8] It is a diagram showing an example of the relationship between the deviation amount of the centroid wavelength and the amount of substance. [Figure 9] It is a configuration diagram of the substance sensing device of the first modified example. [Figure 10] (a) is a diagram showing the wavelength detection unit of the fourth example, and (b) is a diagram showing the wavelength detection unit of the fifth example. [Figure 11] It is a configuration diagram of the substance sensing device of the second modified example. [Figure 12](a) is a diagram showing the light input to the input section in the second modified example, (b) is a diagram showing the light output from the wavelength filter section, (c) is a diagram showing the light transitioning to the ring waveguide, and (d) is a diagram showing the light output from the transmission section. [Figure 13] This is a diagram illustrating the configuration of a material sensing device in the third modified example. [Figure 14] Figure 12 shows an example of the transmission characteristics of a WDM coupler. [Figure 15] This is a diagram showing the configuration of the material sensing device in the fourth modified example. [Figure 16] This is a diagram showing the configuration of the fifth modified material sensing device. [Figure 17] This is a diagram showing the configuration of the sixth modified material sensing device. [Figure 18] This is a diagram illustrating the configuration of the seventh modified material sensing device. [Figure 19] (a), (b), and (c) are diagrams showing the light of each part in the reference example, and (d), (e), and (f) are diagrams showing the light of each part in the seventh modified example. [Modes for carrying out the invention]

[0024] Embodiments of the present invention will be described in detail below with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant explanations will be omitted.

[0025] As shown in Figure 1, the material sensing device 1 is configured to include an optical integrated circuit 10. The optical integrated circuit 10 has a substrate 11, and is constructed by fabricating various optical elements such as optical waveguides on the substrate 11. The substrate 11 is a semiconductor substrate formed of a semiconductor such as silicon. The material sensing device 1 includes a light source 2, an input unit 3, a wavelength filter unit 4, a ring resonator 5, an output unit 6, a wavelength detection unit 8, and a computer 9. The ring resonator 5 has a first waveguide 51, a ring waveguide 52, and a second waveguide 53.

[0026] Light source 2 generates and outputs the measurement light L that is input to input unit 3. In this example, light source 2 is a white light source that generates white light as the measurement light L, but it may also be a tunable light source or a wavelength-swept light source that can change the wavelength of the generated measurement light L.

[0027] The input section 3 is the part that inputs the measurement light L into the optical waveguide of the optical integrated circuit 10, and is formed at one end of the first waveguide 51. The light source 2 is optically connected to the input section 3 via optical elements such as a lens and an optical fiber so that the measurement light L is input to the input section 3. The input section 3 is composed of, for example, a spot size converter (SSC) or a grating coupler (GC).

[0028] The measurement light L input to the input unit 3 is guided to the first waveguide 51 of the ring resonator 5. The wavelength filter unit 4 is provided in the first waveguide 51. The wavelength filter unit 4 transmits light in a predetermined wavelength range (in this example, wavelengths λ1 and above and λ2 and below) while blocking light outside that wavelength range. The wavelength filter unit 4 only needs to include elements that can realize wavelength selection functionality, and is composed of, for example, multiple ring resonators, WDM couplers, fiber Bragg gratings (FBG), circulators, arrayed waveguide gratings (AWG), Mach-Zender interferometers, vernier filters, etc.

[0029] The ring resonator 5 is formed on the substrate 11 and, as described above, has a first waveguide 51, a ring waveguide 52, and a second waveguide 53. A transparent section 51a is formed at the end of the first waveguide 51 opposite to the input section 3. As will be described later, a portion of the measurement light L is output from the transparent section 51a. The ring waveguide 52 is formed in an annular (ring shape) and is optically connected to the first waveguide 51.

[0030] The ring waveguide 52 is provided with multiple (numerous) receptors RP to which the substance S to be sensed binds. For example, the receptor RP is an antibody and the substance S is a protein. The receptor RP is coated on the outer surface of the ring waveguide 52. In Figure 1, the receptor RP is schematically shown on the outer surface of the ring waveguide 52, but in reality, the receptor RP is provided over the entire outer surface of the ring waveguide 52. The substance S binds (attaches) to the receptor RP. The substance S may be a biomaterial such as a protein, bacteria, virus, DNA, or glycans, or it may be a metallic material such as a heavy metal.

[0031] The second waveguide 53 is optically connected to the ring waveguide 52. The ring waveguide 52 guides (transfers) measurement light L, whose resonant wavelength corresponds to the resonator length of the ring waveguide 52, from the first waveguide 51 to the second waveguide 53. The resonant wavelength of the ring waveguide 52 is included in the transmission range (wavelengths λ1 to λ2) of the wavelength filter section 4. The wavelength width of the measurement light L that is transferred from the first waveguide 51 to the second waveguide 53 is, for example, on the order of a few nanometers to sub-nanometers. A portion of the measurement light L that was not guided from the first waveguide 51 to the second waveguide 53 is output to the outside of the substrate 11 from the transmission section 51a provided in the first waveguide 51. During use, the temperature of the ring resonator 5 is kept constant by, for example, a heater.

[0032] The output unit 6 is a part that outputs the measurement light L to the outside of the optical integrated circuit 10 (substrate 11), and is formed on the substrate 11. The output unit 6 is provided at one end of the second waveguide 53 and outputs the measurement light L propagating through the second waveguide 53 to the outside. The output unit 6 is composed of, for example, a spot size converter or a grating coupler. The output unit 6 is optically connected to the wavelength detection unit 8 via optical elements such as a lens and an optical fiber so that the measurement light L is input to the wavelength detection unit 8. Details of the wavelength detection unit 8 will be described later.

[0033] As shown in Figure 2(a), in this example, the measurement light L input to the input unit 3 is white light with equal light intensity at each wavelength. As shown in Figure 2(b), the wavelength filter unit 4 outputs light with wavelengths λ1 to λ2. As shown in Figure 2(c), the measurement light L having wavelengths included in the wavelength range of λ1 to λ2 is transferred to the ring waveguide 52.

[0034] Computer 9 is composed of a computer equipped with, for example, a processor such as a CPU and storage media such as RAM and ROM. Computer 9 functions as a control unit 9a that controls the light source 2 and the wavelength detection unit 8. Computer 9 also functions as a calculation unit 9b that performs predetermined calculations based on the signal output from the wavelength detection unit 8 and calculates the centroid wavelength of the measured light L. Furthermore, as the calculation unit 9b, computer 9 calculates the amount of substance S bound to the receptor RP based on the calculated information regarding the centroid wavelength of the measured light L. Computer 9 is electrically connected to a display unit 9c that displays a GUI (Graphical User Interface) for control display and a GUI for displaying measurement results, and an input unit 9d for inputting control parameters, etc.

[0035] The wavelength detection unit 8 will be described with reference to Figure 3. The first example of the wavelength detection unit 8 shown in Figure 3(a) includes a light separation unit 21, a first detector 25 (photodetector), and a second detector 26 (photodetector). As described above, the measurement light L is input to the wavelength detection unit 8.

[0036] The optical separation unit 21 separates the measurement light L into a first light L1 and a second light L2 at a predetermined separation ratio. In this example, the optical separation unit 21 is composed of an optical filter 21a that separates the measurement light L by transmitting and reflecting it at a predetermined transmittance (separation ratio), thereby separating the measurement light L into the first light L1, which is reflected light, and the second light L2, which is transmitted light. The optical filter 21a is located outside the substrate 11, not on the substrate 11. As shown in Figure 4, the transmittance of the optical separation unit 21 increases linearly in a predetermined wavelength range (wavelengths λ1 to λ2 in this example). In this case, the optical filter 21a is an LRG (Linear Reflectance Gradient on the wavelength axis) filter. In the example in Figure 4, the transmittance (and reflectance) increases linearly in the wavelength range of wavelengths λ1 to λ2, and the transmittance (and reflectance) of light remains constant in wavelength bands other than this wavelength range (shorter wavelengths than wavelength λ1 and longer wavelengths than wavelength λ2). However, the transmittance (and reflectance) of light does not need to be constant in wavelength bands other than the wavelength range specified (shorter wavelengths than wavelength λ1 and longer wavelengths than wavelength λ2).

[0037] Each of the first detector 25 and the second detector 26 is composed of, for example, an image sensor or a point sensor. The first detector 25 detects the first light L1 reflected by the light separation unit 21, and the second detector 26 detects the second light L2 that has passed through the light separation unit 21. The first detector 25 outputs a detection signal to the computer 9 representing the light intensity R of the first light L1 (reflected light) detected by the first detector 25. The second detector 26 outputs a detection signal to the computer 9 representing the light intensity T of the second light L2 (transmitted light) detected by the second detector 26. The sum of the light intensity R of the first light L1 and the light intensity T of the second light L2 corresponds to the total light intensity A (optical power) of the measured light L.

[0038] The second example of the wavelength detection unit 8 shown in Figure 3(b) includes an optical separation unit 21 and a first detector 25, but does not include a second detector 26. In the second example, the optical separation unit 21 is movable between an incident position where the measurement light L is incident on the optical separation unit 21 and a retracted position where the measurement light L is not incident on the optical separation unit 21. In this example, when the optical separation unit 21 is in the incident position, the first light L1 transmitted through the optical separation unit 21 is detected by the first detector 25. In this case, the detection signal output from the first detector 25 when the optical separation unit 21 is in the incident position represents the amount of transmitted light T. Also, when the optical separation unit 21 is in the retracted position, the detection signal output from the first detector 25 corresponds to the total amount of measurement light L A. By subtracting the amount of light T from the total amount of light A, the amount of reflected light R is calculated. In this case, the second light L2 reflected by the optical separation unit 21 is not detected.

[0039] Unlike the above example, the reflective configuration may be such that when the light separation unit 21 is located at the incident position, the first light L1 reflected by the light separation unit 21 is detected by the first detector 25. In this case, the detection signal output from the first detector 25 when the light separation unit 21 is located at the incident position represents the amount of reflected light R. When the light separation unit 21 is located at the retracted position, the detection signal output from the first detector 25 corresponds to the total amount of measured light L A. The amount of transmitted light T is calculated by subtracting the amount of light R from the total amount of light A. In this case, the second light L2 that has passed through the light separation unit 21 is not detected.

[0040] The wavelength detection unit 8 of the third example shown in Figure 3(c) comprises a beam splitter 27, an optical separation unit 21, a first detector 25, and a second detector 26. The beam splitter 27 divides the measurement light L into transmitted light and reflected light in a predetermined ratio. In this example, the optical separation unit 21 is positioned between the beam splitter 27 and the first detector 25, and is configured in a reflective arrangement where reflected light from the beam splitter 27 is incident on the optical separation unit 21. The detection signal output from the first detector 25 (detection signal of the first light L1) corresponds to the amount of transmitted light T. The detection signal output from the second detector 26 corresponds to the total amount of measurement light L A. In this third example, the amount of light T is calculated by considering the reflectance of the beam splitter 27 in relation to the detection signal output from the first detector 25. Specifically, for example, if the beam splitter 27 is a half-mirror, the value corresponding to the detection signal multiplied by the reciprocal of the reflectance 1 / 2 represents the amount of light T. Furthermore, the total light intensity A is calculated by taking into account the transmittance of the beam splitter 27 and the detection signal output from the second detector 26. Specifically, for example, if the beam splitter 27 is a half-mirror, the value corresponding to the detection signal multiplied by the reciprocal of the transmittance of 1 / 2 represents the total light intensity A. By subtracting the light intensity T from the total light intensity A, the amount of reflected light R is calculated. In this case, the second light L2 reflected by the light separation unit 21 is not detected.

[0041] Unlike the above example, the light separation unit 21 may be positioned between the beam splitter 27 and the second detector 26, in a transmission configuration where transmitted light from the beam splitter 27 is incident on the light separation unit 21. In this case, the detection signal output from the second detector 26 corresponds to the amount of transmitted light T. The detection signal output from the first detector 25 corresponds to the total amount of measured light L A. In the modified example of the third example, the amount of light T is calculated by considering the transmittance of the beam splitter 27 with respect to the detection signal output from the second detector 26. Specifically, for example, if the beam splitter 27 is a half mirror, the value corresponding to the detection signal multiplied by the reciprocal of the transmittance 1 / 2 represents the amount of light T. The total amount of light A is calculated by considering the reflectance of the beam splitter 27 with respect to the detection signal output from the first detector 25. Specifically, for example, if the beam splitter 27 is a half mirror, the value corresponding to the detection signal multiplied by the reciprocal of the reflectance 1 / 2 represents the total amount of light A. The amount of reflected light R is calculated by subtracting the amount of light T from the total amount of light A. In this case, the second light L2 that has passed through the light separation unit 21 is not detected. Thus, in any of the first to third examples, if at least two of the following can be detected—the total amount of light A of the measured light L, the amount of light T of the transmitted light that has passed through the light separation unit 21, and the amount of reflected light R of the light reflected by the light separation unit 21—the total amount of light A, the amount of light T, and the amount of light R can be obtained by calculation.

[0042] Referring to Figure 5, the method for calculating the centroid wavelength of the measured light L will be explained. In Figure 5, the horizontal axis represents wavelength, and the vertical axis represents spectral intensity (in the case of the light spectrum) and transmittance (in the case of the light separation unit 21). The centroid wavelength is the weighted average of wavelengths, weighted by spectral intensity (luminance). In other words, the centroid wavelength is the value obtained by dividing the integral of the product of the wavelength of light and the intensity of light at that wavelength over the entire wavelength range by the integral of the intensity of light over the entire wavelength range.

[0043] The wavelength λ50% at which the amount of light T transmitted from the light separation unit 21 and the amount of light R reflected from it are equal is expressed by equation (1).

number

number

[0044] The computer 9 (calculation unit 9b) calculates the centroid wavelength λ of the measurement light L based on the detection results of the first detector 25 and / or the second detector 26. Based on the calculated centroid wavelength λ, the computer 9 (calculation unit 9b) calculates the amount of substance S bound to the receptor RP.

[0045] For example, if we let λ0 be the centroid wavelength of the measurement light L in the reference state shown in Figure 6(a), and let λA and λB be the centroid wavelengths of the measurement light L when the centroid wavelength deviates from the reference state, as shown in Figures 6(b) and 6(c), then the amount of deviation of the centroid wavelength Δλ is expressed as Δλ = λA - λ0 and Δλ = λB - λ0, respectively. The reference state in Figure 6(a) corresponds to a state in which no substance S is bound to the receptor RP, as shown in Figure 7(a). The state in Figure 6(b) corresponds to a state in which a small amount of substance S is bound to the receptor RP, as shown in Figure 7(b). The state in Figure 6(c) corresponds to a state in which a larger amount of substance S is bound to the receptor RP, as shown in Figure 7(c).

[0046] Computer 9 has pre-stored a relationship between the centroid wavelength shift Δλ, as shown in Figure 8, and the amount of substance S coupled to the receptor RP. Computer 9 then calculates the amount of substance based on the centroid wavelength shift Δλ calculated from the detection results of the wavelength detection unit 8 (first detector 25 / second detector 26) and the aforementioned relationship. This amount of substance represents the sensing result of the substance sensing device 1. The refractive index of the ring waveguide 52 changes according to the amount of substance S coupled to the receptor RP provided in the ring waveguide 52 (number of substances, concentration). When the refractive index of the ring waveguide 52 changes, the resonance wavelength changes, and the centroid wavelength λ of the measurement light L output from the ring resonator 5 also changes. Therefore, the amount of substance S coupled to the receptor RP can be calculated based on the centroid wavelength λ of the measurement light L and the above relationship.

[0047] The processing performed by the material sensing device 1 can also be considered as a material sensing method using the material sensing device 1. In the material sensing method, first, measurement light L from the light source 2 is input to the first waveguide 51 of the ring resonator 5, and at least one of the first light L1 and the second light L2 is detected by the wavelength detection unit 8 (photodetection step). Subsequently, the computer 9 (calculation unit 9b) calculates the centroid wavelength λ of the measurement light L based at least on the detection result of the photodetection step, and calculates the amount of material S coupled to the receptor RP based on the calculated centroid wavelength λ (calculation step). This enables sensing of material S. [Mechanism of Action and Effects]

[0048] The material sensing device 1 receives measurement light L traveling through the second waveguide 53 and includes an optical separation unit 21 that separates the measurement light L into a first light L1 and a second light L2 at a predetermined separation ratio. This separation ratio changes monotonically in a predetermined wavelength range. At least one of the first light L1 and the second light L2 is detected by the first detector 25 and / or the second detector 26, and the centroid wavelength λ of the measurement light L is calculated based at least on the detection results of the first detector 25 and / or the second detector 26. Based on the calculated centroid wavelength λ, the amount of substance S bound to the receptor RP is calculated. This allows the centroid wavelength λ of the measurement light L to be calculated with high wavelength resolution, and the amount of substance bound to the receptor RP can be calculated with high accuracy. Therefore, the material sensing device 1 can perform material sensing with high accuracy.

[0049] The material sensing device 1 is provided in the first waveguide 51 and includes a wavelength filter 4 that transmits light in a predetermined wavelength range (wavelengths λ1 to λ2) while blocking light outside that range. This makes it possible to suppress the input of light having peaks in wavelength ranges other than the predetermined wavelength range where the separation rate changes monotonically to the optical separation unit 21. For example, since the ring resonator 5 has resonant wavelengths at intervals of several tens of nanometers, when white light is input to the ring resonator 5, there is a possibility that light having peaks in wavelength ranges other than the target wavelength range (wavelengths λ1 to λ2) will also be guided to the second waveguide 53 (optical separation unit 21). By providing the wavelength filter 4, it is possible to suppress the input of such light to the optical separation unit 21.

[0050] The light separation unit 21 is an optical filter 21a located outside the substrate 11. This allows the light separation unit 21 to be realized using an optical filter 21a located outside the substrate 11.

[0051] A first detector 25 for detecting the first light L1 and a second detector 26 for detecting the second light L2 are provided as a photodetector. This makes it possible to calculate the centroid wavelength λ of the measured light L based on the detection results of both the first light L1 and the second light L2. [Differentiation]

[0052] The first modified material sensing device 1 shown in Figure 9 is equipped with a branching coupler 31. The branching coupler 31 is provided in the second waveguide 53 and branches the measurement light L propagating through the second waveguide 53 at a predetermined ratio. A portion of the branched measurement light L is output from the second output unit 31a and input to the wavelength detection unit 8. The remaining portion of the measurement light L is output from the output unit 6 and input to the photodetector 32.

[0053] In the first modified example, the wavelength detection unit 8 may be configured as in the fourth example shown in Figure 10(a), or as in the fifth example shown in Figure 10(b). In the fourth example shown in Figure 10(a), the first light L1, which is transmitted light from the light separation unit 21, is detected by the first detector 25. In this case, the detection signal output from the first detector 25 corresponds to the amount of transmitted light T. The detection signal output from the photodetector 32 corresponds to the total amount of measured light L A. The amount of reflected light R is calculated by subtracting the amount of light T from the total amount of light A.

[0054] In the fifth example shown in Figure 10(b), the first light L1, which is reflected light from the light separation unit 21, is detected by the first detector 25. In this case, the detection signal output from the first detector 25 corresponds to the amount of reflected light R. The detection signal output from the photodetector 32 corresponds to the total amount of measured light L A. By subtracting the amount of light R from the total amount of light A, the amount of transmitted light T is calculated. Even with this first modified example, accurate material sensing can be performed in the same way as in the above embodiment.

[0055] In the above embodiment, the measurement light L traveling through the second waveguide 53 was input to the wavelength detection unit 8. However, as shown in the second modified example in Figure 11, the measurement light L traveling through the first waveguide 51 and output from the transmission unit 51a may also be input to the wavelength detection unit 8. The light output from the transmission unit 51a is the light obtained by subtracting the light that has transitioned to the ring waveguide 52 from the light input to the input unit 3. For example, as shown in Figure 12(a), if the measurement light L is white light, the measurement light L output from the transmission unit 51a has a spectrum where the peak of the light that has transitioned to the ring waveguide 52 is the bottom (Figures 12(c) and 12(d)). Since the spectrum of the measurement light L output from the transmission unit 51a changes with the change in the resonant wavelength of the ring resonator 5, in this case as well, the amount of substance S coupled to the receptor RP can be calculated based on the centroid wavelength λ of the measurement light L. With this second modified example, accurate substance sensing can be performed in the same way as in the above embodiment.

[0056] The third modified material sensing device 1 shown in Figure 13 is equipped with a wavelength division multiplexing (WDM) coupler (wavelength separation coupler) 21b as an optical separation unit 21. The WDM coupler 21b is formed on the substrate 11 and is provided in the second waveguide 53. The WDM coupler 21b separates the measurement light L by splitting it with a predetermined transmittance (separation rate, branching rate). As shown in Figure 14, the transmittance of the WDM coupler 21b increases linearly in a predetermined wavelength range (linear wavelength range). Therefore, by designing the WDM coupler 21b so that the wavelength range of the measurement light L is included in the linear wavelength range, the WDM coupler 21b can be made to function as an optical separation unit 21. In this specification, light that propagates through the second waveguide 53 without being branched by the WDM coupler 21b is called "transmitted light," and light that has been branched by the WDM coupler 21b is called "reflected light."

[0057] In the third modified example, the first detector 25 and the second detector 26 are formed on the substrate 11. The first detector 25 and the second detector 26 are composed of, for example, germanium photodiodes. The first detector 25 detects the first light L1 propagating through the second waveguide 53 without being branched by the WDM coupler 21b. The second detector 26 detects the second light L2 that has been branched by the WDM coupler 21b. The detection signal output from the first detector 25 corresponds to the amount of transmitted light T in the above embodiment. The detection signal output from the second detector 26 corresponds to the amount of reflected light R in the above embodiment. Therefore, even with this third modified example, accurate material sensing can be performed in the same way as in the above embodiment. Furthermore, in the second modified example, the light separation unit 21 can be realized using the WDM coupler 21b.

[0058] The fourth modified material sensing device 1 shown in Figure 15 differs from the third modified example in that the first detector 25 and the second detector 26 are provided outside the substrate 11. For example, the first detector 25 detects the measurement light L output from the first output unit 6a formed on the substrate 11, and the second detector 26 detects the measurement light L output from the second output unit 6b formed on the substrate 11. The fifth modified material sensing device 1 shown in Figure 16 differs from the third modified example in that the light source 2 is formed on the substrate 11. These fourth and fifth modified examples can also perform material sensing with high accuracy, similar to the embodiments described above.

[0059] In the sixth modified material sensing device 1 shown in Figure 17, the ring resonator 5 has multiple (two in this example) ring waveguides 52 and multiple (two in this example) second waveguides 53. One ring waveguide 52 (first ring waveguide) is optically connected to the first waveguide 51 and one of the second waveguides 53, and the other ring waveguide 52 (second ring waveguide) is optically connected to the first waveguide 51 and the other second waveguide 53. The material sensing device 1 is equipped with multiple (two in this example) wavelength detection units 8, each provided in one of the multiple second waveguides 53. The computer 9 calculates the amount of material S coupled to the receptor RP of each ring waveguide 52 based on the detection results of the multiple wavelength detection units 8.

[0060] This sixth modification also allows for accurate material sensing, similar to the above embodiment. Furthermore, by varying the type of receptor RP provided in each ring waveguide 52, it is possible to sense multiple types of materials S. That is, the material S coupled to the receptor RP of one ring waveguide 52 (first ring waveguide) may be different from the material S coupled to the receptor RP of the other ring waveguide 52 (second ring waveguide). However, the material S measured in each ring waveguide 52 may be the same. In the sixth modification, it is preferable that the resonant wavelengths of the multiple ring waveguides 52 are different (non-overlapping) wavelengths. For example, if the wavelength range in which the separation ratio changes in one optical separation unit 21 is λ1 to λ2, and the resonant wavelength of one ring waveguide 52 is a wavelength within the wavelength range λ1 to λ2, it is preferable that the wavelength range in which the separation ratio changes in the other optical separation unit 21 is λ3 to λ4, and the resonant wavelength of the other ring waveguide 52 is a wavelength within the wavelength range λ3 to λ4.

[0061] In the seventh modified material sensing device 1 shown in Figure 18, the ring resonator 5 has multiple (two in this example) ring waveguides 52. The two ring waveguides 52 include a first ring waveguide 52a and a second ring waveguide 52b that are optically connected in series. The first ring waveguide 52a is connected to the first waveguide 51, and the second ring waveguide 52b is connected to the second waveguide 53. In this example, the first ring waveguide 52a is provided with a receptor RP, while the second ring waveguide 52b is not. When the light guiding the first ring waveguide 52a satisfies the resonance condition with the second ring waveguide 52b, the first ring waveguide 52a couples with the second ring waveguide 52b, and light propagates from the first ring waveguide 52a to the second ring waveguide 52b. Therefore, the resonant wavelength of the ring resonator 5 can be limited, and the interval between resonant wavelengths can be widened. As a result, the wavelength range λ1 to λ2 of the separation rate change in the optical separation unit 21 can be designed to be wider, improving the design flexibility of the optical separation unit 21. In addition, the degree of freedom in selecting the wavelength filter unit 4 can also be improved.

[0062] This point will be further explained with reference to Figure 19. Figures 19(a) to 19(c) show the light at each part in the reference example, and Figures 19(d) to 19(f) show the light at each part in the seventh modified example. The optical path length difference (OPD) of a single-ring resonator having only one ring waveguide is calculated by equation (4). OPD = 2πrn (4) In equation (4), r is the diameter of the ring resonator, and n is the effective refractive index of the material of the ring resonator. In order to produce resonance, the resonance condition in equation (5) must be satisfied. OPD = mλ m (5) In equation (5), λ m λ is the resonant wavelength of the ring resonator, and m is the mode index of the ring resonator. In other words, for the light being guided to produce constructive interference in the ring resonator, the circumference of the ring waveguide, considering the refractive index, must be an integer multiple of the wavelength of light. Therefore, the resonant wavelength λ mcan be determined from the diameter r, refractive index n, and mode index m of the ring resonator, and can take a plurality of values depending on the mode index (Equations (6) and (7)). Therefore, when white light is input, the wavelengths of the light passing through the ring resonator can be plural. mλ m = 2πrn (6) λ m = 2πrn / m (7) As shown in FIGS. 19(a) to 19(c), when the resonance wavelength λ m , λ m+1 exists within the wavelength range λ1 to λ2 of the optical separation unit 21, the center wavelengths of these lights are calculated. Therefore, in the case of a single ring resonator, it is necessary to design the ring resonator 5 and the optical separation unit 21 so that only one resonance wavelength exists within the wavelength range λ1 to λ2 of the optical separation unit 21.

[0063] On the other hand, in the case of a series ring resonator having a first ring waveguide and a second ring waveguide connected in series, in order to pass through both of the two ring waveguides, it is necessary to satisfy both of the two resonance conditions of Equations (8) and (9). m1λ m1 = 2πr1n1 m2λm2 = 2πr2n2 In Equations (8) and (9), r1 is the diameter of the first ring waveguide, n1 is the effective refractive index of the material of the first ring waveguide, λ m1 is the resonance wavelength of the first ring waveguide, m1 is the mode index of the first ring waveguide, r₂ is the diameter of the second ring waveguide, n₂ is the effective refractive index of the material of the second ring waveguide, and λ m2 is the resonance wavelength of the second ring waveguide, and m2 is the mode index of the ring resonator of the second ring waveguide. That is, the light output from the first ring waveguide and the second ring waveguide connected in series becomes the mode index m' of the composite ring (series ring resonator) that satisfies the above two resonance conditions. As shown in FIGS. 19(d) to 19(f), in the case of a series ring resonator, λ m’ and λ m’+1The spacing between the rings can be widened, and constraints such as narrowing the wavelength range λ1 to λ2, as is the case with single-ring resonators, can be suppressed.

[0064] The present invention is not limited to the above embodiments and modifications. In the above embodiments and each modification, the wavelength filter unit 4 may be provided in the second waveguide 53. In the above embodiments and modifications, the control unit 9a and the calculation unit 9b are configured by a single device (computer 9), but the control unit 9a and the calculation unit 9b may be configured by separate devices (e.g., computers). The transmission range through which the wavelength filter unit 4 transmits light does not have to coincide with the wavelength range in which the transmittance of the light separation unit 21 changes monotonically, but only needs to include at least a part of that wavelength range.

[0065] In the above embodiments and modified examples, the transmittance (separation rate) of the light separation unit 21 increased linearly in a predetermined wavelength range. However, the transmittance of the light separation unit 21 only needs to change monotonically in a predetermined wavelength range; for example, it may decrease linearly, or it may increase or decrease in a manner other than linear.

[0066] In the above embodiments and modifications, the centroid wavelength λ of the measurement light L was calculated based on the detection results of the first detector 25 and / or the second detector 26. However, it is not necessary to calculate the centroid wavelength λ of the measurement light L; it is sufficient to obtain information regarding the centroid wavelength λ of the measurement light L based on the detection results of the first detector 25 and / or the second detector 26. Information regarding the centroid wavelength λ of the measurement light L refers to, for example, information that allows for the calculation of the centroid wavelength λ of the measurement light L. In the above embodiments and modifications, the amount of substance S bound to receptor RP was calculated based on the centroid wavelength λ of the measurement light L; however, it is not necessary to calculate the amount of substance; it is sufficient to obtain information regarding the amount of substance based on information regarding the centroid wavelength λ of the measurement light L. Information regarding the amount of substance refers to, for example, information that allows for the calculation of the amount of substance based on that information. Information regarding the amount of substance may be, for example, the number or concentration of substance S bound to receptor RP.

[0067] In the third modified example shown in Figure 13, the WDM coupler 21b (optical separation unit 21) was provided in the second waveguide 53. However, in the third modified example, the WDM coupler 21b may be provided on the side of the transparent section 51a rather than the connection point with the ring waveguide 52 in the first waveguide 51. Material sensing can also be performed in this case. [Explanation of Symbols]

[0068] 1...Material sensing device, 2...Light source, 4...Wavelength filter section, 5...Ring resonator, 9b...Calculation unit, 10...Optical integrated circuit, 11...Substrate, 21...Optical separation unit, 21a...Optical filter, 21b...Wavelength division multiplexing coupler, 25...First detector (photodetector), 26...Second detector (photodetector), 51...First waveguide, 52...Ring waveguide, 53...Second waveguide, L...Measurement light, L1...First light, L2...Second light, RP...Receptor, S...Material.

Claims

1. An optical integrated circuit having a substrate, A ring resonator formed on the substrate, the ring resonator having a first waveguide into which measurement light having a predetermined wavelength is input, a ring waveguide provided with a plurality of receptors to which material is coupled and optically connected to the first waveguide, and a second waveguide optically connected to the ring waveguide, the ring resonator guiding the measurement light having a resonant wavelength corresponding to the resonator length of the ring waveguide from the first waveguide through the ring waveguide to the second waveguide, An optical separation unit receives the measurement light traveling through the first waveguide or the measurement light traveling through the second waveguide, and separates the measurement light into first light and second light at a predetermined separation ratio, wherein the separation ratio changes monotonically in a predetermined wavelength range. A light detection unit that detects at least one of the first light and the second light, A material sensing device comprising: a calculation unit that acquires information regarding the centroid wavelength of the measurement light based at least on the detection result of the light detection unit, and acquires information regarding the amount of the substance bound to the plurality of receptors based on the acquired information regarding the centroid wavelength.

2. The material sensing device according to claim 1, further comprising a wavelength filter section provided in the first waveguide, which transmits light in a transmission range including at least a portion of the predetermined wavelength range while blocking light outside the transmission range.

3. The material sensing device according to claim 1 or 2, wherein the light separation unit is a wavelength separation coupler formed on the substrate.

4. The material sensing device according to claim 3, wherein the wavelength separation coupler is a wavelength division multiplex coupler.

5. The material sensing device according to claim 1 or 2, wherein the light separation unit is an optical filter disposed outside the substrate.

6. The material sensing device according to claim 1 or 2, wherein the light detection unit comprises a first detector for detecting the first light and a second detector for detecting the second light.

7. The material sensing device according to claim 1 or 2, wherein the ring resonator has a plurality of ring waveguides, and the plurality of ring waveguides are optically connected in series.

8. The material sensing device according to claim 1 or 2, wherein the light detection unit is formed on the substrate.

9. The material sensing device according to claim 1 or 2, further comprising a light source that outputs the measurement light, wherein the light source is formed on the substrate.

10. The material sensing device according to claim 1 or 2, wherein the ring resonator has a plurality of ring waveguides, the plurality of ring waveguides include a first ring waveguide and a second ring waveguide, and the material coupled to the plurality of receptors of the first ring waveguide is different from the material coupled to the plurality of receptors of the second ring waveguide.

11. circuit board and A ring resonator formed on the substrate, the ring resonator having a first waveguide into which measurement light having a predetermined wavelength is input, a ring waveguide provided with a plurality of receptors to which material is coupled and optically connected to the first waveguide, and a second waveguide optically connected to the ring waveguide, the ring resonator guiding the measurement light having a resonant wavelength corresponding to the resonator length of the ring waveguide from the first waveguide through the ring waveguide to the second waveguide, An optical integrated circuit comprising: an optical separation unit formed on the substrate, which receives the measurement light traveling through the first waveguide or the measurement light traveling through the second waveguide, and separates the measurement light into first light and second light at a predetermined separation ratio, wherein the separation ratio changes monotonically in a predetermined wavelength range.

12. A material sensing method using a material sensing device, The material sensing device, An optical integrated circuit having a substrate, A ring resonator formed on the substrate, the ring resonator having a first waveguide into which measurement light having a predetermined wavelength is input, a ring waveguide provided with a plurality of receptors to which material is coupled and optically connected to the first waveguide, and a second waveguide optically connected to the ring waveguide, the ring resonator guiding the measurement light having a resonant wavelength corresponding to the resonator length of the ring waveguide from the first waveguide through the ring waveguide to the second waveguide, The optical separation unit receives the measurement light traveling through the first waveguide or the measurement light traveling through the second waveguide, and separates the measurement light into a first light and a second light at a predetermined separation ratio, wherein the separation ratio changes monotonically in a predetermined wavelength range. The aforementioned material sensing method is A photodetection step in which the measurement light is input to the first waveguide and at least one of the first light and the second light is detected, A material sensing method comprising: a calculation step of acquiring information regarding the centroid wavelength of the measurement light based at least on the detection result of the light detection step, and acquiring information regarding the amount of the substance bound to the plurality of receptors based on the acquired information regarding the centroid wavelength.

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