Light source device and light measurement device

Abstract

To suppress reduction in the measurement accuracy caused by variations in the spectral characteristic of an AWG in a light measurement device.SOLUTION: A pulse light source 210 generates a broadband pulse light L1a. An AWG260A spacially divides the broadband pulse light L1a according to the wavelength and emits a plurality of divisional beams. The fibers 230_1 to 230_n provide the divisional beams with different delays. A coupler 250 spacially couples plural beams output from the fibers 230_1 to 230_n. The AWG260A includes plural incident waveguides 262_1 to 262_3 and one of the incident waveguides 262_1 to 262_3 is configured to selectively receive input of the broadband pulse light L1a.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a light source device and a light measurement device. [Background technology]

[0002] Spectroscopic analysis is widely used to analyze and inspect the components of objects. In spectroscopic analysis, an object is irradiated with irradiating light, and the spectrum of the object light obtained as a result of the irradiation is measured. Then, optical characteristics such as reflection characteristics (wavelength dependence) or transmission characteristics can be obtained based on the relationship between the spectrum of the object light and the spectrum of the irradiating light.

[0003] Swept-wavelength spectroscopy is known as one of the methods for measuring optical properties. Swept-wavelength spectroscopes generate swept-wavelength light, whose wavelength changes over time, and irradiate the test object with it. The swept-wavelength light is a pulse or pulse train in which time and wavelength have a one-to-one relationship. The time waveform of the light obtained by irradiating the test object with the swept-wavelength light is detected by a photoreceiver. The output waveform of the photoreceiver represents a spectrum in which the time axis corresponds to the wavelength.

[0004] Patent Document 1 discloses a light source device for a spectroscopic measurement device of wavelength sweep type spectroscopy. FIG. 1 is a diagram for explaining a conventional light source device 200R. This light source device 200R includes a pulse light source 210, a splitter 220, a plurality of n (n≧2) fibers 230_1 to 230_n, and a coupler 240. The splitter 220 includes an arrayed waveguide grating (AWG) 222 and splits the pulse light from the pulse light source 210 into a plurality of n pieces according to the wavelength. The plurality of n fibers 230_1 to 230_n give different delays to the n pieces of light split by the splitter 220. The coupler 240 spatially overlaps the lights output from the plurality of n fibers 230_1 to 230_n so that the lights are irradiated to the same irradiation area. In Patent Document 1, the splitter 220 includes an AWG 222. Also, one configuration example of coupler 240 is disclosed that includes an AWG 242, similar to splitter 220. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-159973 A Summary of the Invention [Problem to be solved by the invention]

[0006] As a result of examining the light source device 200R of FIG. 1, the inventors have come to recognize the following problem.

[0007] When quantitative measurement of an object is performed using a spectroscopic measurement device using an AWG, a calibration curve is created in advance using multivariate analysis or the like to calculate component values ​​from the spectrum. Then, quantitative measurement of the object is performed according to the created calibration curve model.

[0008] In the AWG film formation process, it is difficult to achieve a completely uniform refractive index and film thickness within the same wafer or between different wafers, which results in variations in the spectral characteristics of each individual AWG.

[0009] Therefore, if the spectroscopic characteristics of the AWG used to create the calibration curve model differ from those of the AWG incorporated in the spectroscopic measurement device that actually measures the sample, a problem will occur (reduced accuracy) in which the measurement results will differ even for the same object.

[0010] It should be noted that this problem should not be taken as a common understanding among those skilled in the art, but rather is something that the present inventors have independently recognized.

[0011] The present disclosure has been made in consideration of such problems, and one exemplary purpose of an embodiment thereof is to provide a light measurement device and a light source device that can suppress a decrease in measurement accuracy caused by variations in the spectroscopic characteristics of an AWG. [Means for solving the problem]

[0012] A light source device according to an embodiment of the present disclosure generates wavelength-swept light. The light source device includes a pulse light source that generates pulse light, an arrayed-waveguide grating that spatially divides the pulse light according to wavelength and outputs multiple divided beams, a plurality of fibers that give different delays to the multiple divided beams, and a coupler that spatially combines the multiple beams output from the multiple fibers. The arrayed-waveguide grating includes a plurality of input waveguides and a plurality of output waveguides, and is configured to be able to selectively input the pulse light to one of the multiple input waveguides.

[0013] In addition, any combination of the above components, and mutual substitution of the components and expressions of the present disclosure between methods, devices, systems, etc. are also valid aspects of the present disclosure. Effect of the Invention

[0014] According to an aspect of the present disclosure, it is possible to suppress a decrease in measurement accuracy caused by variations in the spectroscopic characteristics of the AWG. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram illustrating a conventional light source device. [Diagram 2] 1 is a block diagram showing a basic configuration of a light measurement device according to an embodiment. [Diagram 3] FIG. 13 is a diagram showing wavelength swept light L1. [Figure 4] 3 is a diagram for explaining light scattering by the light measurement device of FIG. 2. [Diagram 5] 1 is a diagram showing a light source device according to a first embodiment. [Figure 6] FIG. 2 is a diagram illustrating the spectroscopic characteristics of the AWG according to the first embodiment. [Figure 7] FIG. 13 is a diagram showing the measurement results of the shift amounts of the central wavelengths λ1 to λ64 of the channels Ch1 to Ch64 when the incident position with respect to the incident slab waveguide is shifted by 10 nm. [Figure 8] FIG. 13 is a diagram illustrating the selection of an input waveguide. [Figure 9]FIG. 13 is a diagram showing the measurement results using a reference AWG. [Figure 10] FIG. 13 shows measurement results when three alternative AWGs are used. [Figure 11] FIG. 11 is a diagram showing a light source device according to a second embodiment. [Figure 12] 10 is a diagram illustrating the spectroscopic characteristics of an AWG according to the second embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] (Overview of the embodiment) A summary of some exemplary embodiments of the present disclosure will be described. This summary is intended to provide a simplified summary of some concepts of one or more embodiments in order to provide a basic understanding of the embodiments as a prelude to the detailed description that follows, and is not intended to limit the scope of the invention or disclosure. Furthermore, this summary is not intended to be a comprehensive overview of all possible embodiments, nor is it intended to limit essential components of the embodiments. For convenience, the term "one embodiment" may be used to refer to one embodiment (example or variant) or multiple embodiments (examples or variants) disclosed in this specification.

[0017] A light source device according to one embodiment generates wavelength-swept light. The light source device includes a pulse light source that generates pulse light, an arrayed waveguide grating (AWG) that spatially divides the pulse light according to wavelength and outputs multiple divided beams, multiple fibers that give different delays to the multiple divided beams, and a coupler that spatially combines the multiple beams output from the multiple fibers. The arrayed waveguide grating includes multiple input waveguides and multiple output waveguides, and is configured to be able to selectively input the pulse light to one of the multiple input waveguides.

[0018] Due to variations in the manufacturing process of the AWG, the spectral characteristics, specifically the central wavelength of each split beam, shift from the design value. In this light source device, the shift in the central wavelength of each split beam can be canceled by changing the input waveguide into which the pulsed light is input according to the amount of shift in the central wavelength. In an optical measurement device using such a light source device, the effect of variations in the spectral characteristics of the AWG is suppressed, thereby improving measurement accuracy.

[0019] In one embodiment, the wavelength interval (design value) of the central wavelengths of the split beams output from the multiple output waveguides may be X. The AWG may be configured so that when the input waveguide into which the pulsed light is input is shifted by one, the wavelengths of the split beams output from each output waveguide are shifted by Y+X.

[0020] In one embodiment, the number of the plurality of output waveguides may be greater than the number of the plurality of fibers, and the plurality of output waveguides to which the plurality of fibers should be connected may be changed depending on the input waveguide into which the pulsed light is input. In this way, split beams having the same wavelength can be output from the same fiber regardless of the selection of the input waveguide into which the pulsed light is input.

[0021] In one embodiment, the number of input waveguides may be three or more.

[0022] In one embodiment, the wavelength of the pulsed light may include 900 to 1300 nm.

[0023] In one embodiment, the material of the arrayed waveguide grating is SiO 2 may be also possible.

[0024] In one embodiment, the coupler may be an arrayed waveguide grating.

[0025] An optical measurement device according to one embodiment may include any of the above-described light source devices that generate wavelength swept light, and a light receiving device that measures object light obtained by irradiating an object with the wavelength swept light.

[0026] (Embodiment) Hereinafter, the present disclosure will be described with reference to the drawings based on preferred embodiments. The same or equivalent components, parts, and processes shown in each drawing will be given the same reference numerals, and duplicated descriptions will be omitted as appropriate. In addition, the embodiments are not intended to limit the disclosure, but are merely examples, and all features and combinations thereof described in the embodiments are not necessarily essential to the disclosure.

[0027] The dimensions (thickness, length, width, etc.) of each component shown in the drawings may be enlarged or reduced as appropriate for ease of understanding. Furthermore, the dimensions of multiple components do not necessarily represent their relative sizes. Even if a component A is drawn thicker than another component B on the drawings, component A may actually be thinner than component B.

[0028] 2 is a block diagram showing a basic configuration of a light measurement device 100 according to an embodiment. The light measurement device 100 is a wavelength sweep type spectroscope that measures the spectrum of an object OBJ, and mainly includes a light source device 200, a light receiving device 300, and an arithmetic processing device 400. In some figures, the light source device 200, the light receiving device 300, etc. may be simplified and shown as boxes, but this does not mean that the components constituting each are housed in a single housing.

[0029] The light source device 200 irradiates the object OBJ with swept light L1, whose wavelength changes over time. The swept light L1 has a one-to-one correspondence between time and wavelength. This means that the swept light L1 has a "unique wavelength."

[0030] FIG. 3 is a diagram showing the wavelength swept light L1. The upper part of FIG. 3 shows the intensity (time waveform) I WS The lower part shows the time variation of the wavelength λ of the wavelength swept light L1. In this example, the wavelength swept light L1 is a single pulse light, and its dominant wavelength is λ 1 , with a dominant wavelength of λ at the trailing edge n and the wavelength within one pulse is λ 1 From λn In this example, the wavelength swept light L1 is a positive chirped pulse (λ 1 >λ n ) The wavelength swept light L1 may be a negative chirp pulse whose wavelength increases with time (λ 1 <λ n As will be described later, the wavelength swept light L1 may be a pulse train.

[0031] Returning to FIG. 2, the light receiving device 300 receives light (object light) L2 obtained as a result of irradiating the object OBJ with the wavelength swept light L1. The object light L2 may be reflected light or transmitted light. The light receiving device 300 includes optical sensors 302 and 304 such as photodiodes, an A / D converter 310, an optical system (not shown), and the like. The object light L2 is detected by the optical sensor 302. A portion of the wavelength swept light L1 generated by the light source device 200 is extracted as reference light L3 via a separate path using an optical element such as a beam splitter, and is detected by the optical sensor 304.

[0032] The A / D converter 310 converts the output signals S2 and S3 of the optical sensors 302 and 304 into digital signals D2 and D3. OBJ (t) and the time waveform I of the reference light L3 indicated by the digital signal D3 REF (t) is input to the processor 400 .

[0033] In wavelength-swept spectroscopy, there is a one-to-one correspondence between time and wavelength in the wavelength-swept light L1. This correspondence is of course also held by the reference light L3, and is also inherited by the object light L2. Using this correspondence between time and wavelength, the arithmetic processing device 400 calculates the time waveform I OBJ (t) is the frequency domain spectrum I OBJ (λ). The arithmetic processing device 400 also converts the time waveform I REF (t) is converted to a spectrum and appropriately scaled to obtain the reference spectrum I REFCalculate (λ).

[0034] The processing of the arithmetic processing device 400 is not particularly limited. As an example, the arithmetic processing device 400 may REF (λ) and the spectrum of the object light L2 OBJ Based on (λ), the transmittance T(λ) of the object OBJ can be calculated. The same goes for the reflectance R(λ). T(λ)=I OBJ (λ) / I REF (λ) R(λ)=I OBJ (λ) / I REF (λ)

[0035] In addition, when the stability of the wavelength swept light L1 is high, the spectrum of the wavelength swept light L1 is measured in advance and a reference spectrum I REF (λ) may also be used.

[0036] 4 is a diagram for explaining the light splitting by the light measurement device 100 of FIG. 2. As described above, the wavelength swept light L1 has a one-to-one correspondence between time t and wavelength λ, so that its time waveform I REF (t) is the frequency domain spectrum I REF (λ).

[0037] Time waveform I of object light L2 OBJ In the case of (t), time t and wavelength λ correspond one-to-one. Therefore, the processor 400 calculates the waveform I OBJ (t) is the spectrum I of the object light L2 OBJ (λ).

[0038] The processor 400 extracts two spectra I OBJ (λ) and I REF (λ) ratio I OBJ (λ) / I REF Based on (λ), the transmission spectrum T(λ) of the object OBJ can be calculated.

[0039] The relationship between the wavelength λ of the wavelength swept light L1 and time t is expressed as a function λ=f(t). In the simplest terms, the wavelength λ changes linearly with respect to time t according to a linear function. OBJ (t) is the time t x When the transmission spectrum T(λ) decreases at wavelength λ x =f(t x ) means that it has an absorption spectrum at

[0040] The processing in the arithmetic processing device 400 is not limited to this. OBJ (t) and I REF (t) ratio T(t) = I OBJ (t) / I REF After calculating (t), the variable t of this time waveform T(t) may be converted to λ to calculate the transmission spectrum T(λ).

[0041] The above is the basic configuration and operation of the light measurement device 100. Next, the configuration of the light source device 200 will be described.

[0042] (Embodiment 1) 5 is a diagram showing a light source device 200A according to embodiment 1. The light source device 200A includes a pulse light source 210, a splitter 220, a plurality of n (n≧2) fibers 230_1 to 230_n (collectively referred to as a fiber array 232), and a coupler 250.

[0043] The pulse light source 210 emits broadband pulsed light L1a having a broad, continuous spectrum. The spectrum of the broadband pulsed light L1a is continuous over a wavelength range of at least 10 nm, preferably 50 nm, and more preferably 100 nm, for example, in the range of 900 nm to 1300 nm. The width of the wavelength range of the broadband pulsed light L1a needs only to cover the wavelength range required for spectroscopy.

[0044] For example, the pulsed light source 210 may include an ultrashort pulsed laser and a nonlinear element. Examples of the ultrashort pulsed laser include a gain-switched laser, a microchip laser, and a fiber laser.

[0045] The nonlinear element uses nonlinear phenomena to further broaden the spectral width of the ultrashort pulses generated by the ultrashort pulse laser. A fiber is suitable as the nonlinear element, and for example, a photonic crystal fiber or other nonlinear fiber can be used. A single mode fiber is suitable, but a multimode fiber can also be used as long as it shows sufficient nonlinearity.

[0046] As the pulsed light source 210, other broadband pulsed light sources such as a superluminescent diode (SLD) light source may be used.

[0047] The broadband pulsed light L1a output from the nonlinear element has a pulse width on the order of femtoseconds to nanoseconds. The splitter 220, the fiber array 232, and the coupler 250 receive the broadband pulsed light L1a and convert it into wavelength swept light L1.

[0048] The splitter 220 includes an arrayed waveguide grating (AWG) 260 and a lens 224. The lens 224 focuses the wideband pulsed light L1a emitted by the pulse light source 210 onto an input end of the AWG260.

[0049] The AWG 260 splits the broadband pulsed light L1a into multiple n beams (called split beams) L1b according to the wavelength. 1 ~L1b n The number of divisions (number of channels) n is equal to the number of fibers 230. The number of channels n can be, for example, 4, 8, 16, 32, 64, 128, etc. The wavelength λ of the i-th (1≦i≦n) split beam of light is i The split beam L1b 1 ~L1b n Since each of the wavelengths is not a single spectrum but has a certain wavelength width, λ i is not a single wavelength, but L1b iFor convenience, the wavelength band of the AWG 260 is used as a wavelength band, and the center wavelength of the wavelength band is used as a wavelength band. i+1 -λ i (i=1, 2, 3...) are substantially equal. The material of the waveguide of AWG260A is SiO 2 may also be used.

[0050] Split beam L1b output from AWG260 1 ~L1b n The i-th split beam L1b is guided to the corresponding fibers 230_1 to 230_n that constitute the fiber array 232. Specifically, the i-th split beam L1b i are coupled to the input ends of the corresponding fibers 230_i.

[0051] Assume that the broadband pulse light L1a before division is a positive chirp pulse (up-chirp pulse) whose frequency increases (wavelength shortens) over time. In other words, the longest wavelength λ is present at the leading edge of the pulse. 1 The pulse has a shortest wavelength, λ n Contains the following ingredients.

[0052] The multiple fibers 230_1 to 230_n have different lengths l 1 ~l n It has λ 1 is the longest wavelength, λ n If is the shortest wavelength, then in order to make the wavelength swept light L1 a positive chirped pulse like the broadband pulse light L1a, 1 1 <l 2 <… <l n As an example, when n=20, the length l of the fiber 230 is 1 ~l n may be increased in 1m increments from 1m to 20m.

[0053] The fibers 230_1 to 230_n do not need to have different group delay characteristics for each wavelength, and the same fiber (fibers having the same core / clad material) can be used. In this sense, the fiber 230 can be a multimode fiber, which is advantageous in that unintended nonlinear optical effects can be prevented.

[0054] The coupler 250 couples multiple split beams L1c with different delays provided by the fiber array 232. 1 ~L1c n The configuration of the coupler 250 is not particularly limited in this disclosure, and any known or future available configuration may be used.

[0055] In this embodiment, the AWG 260A includes a plurality of m (m≧2) input waveguides 262_1 to 262_m, an input slab waveguide 264, an arrayed waveguide 266, an output slab waveguide 268, and a plurality of n output waveguides 270_1 to 270_n. In this embodiment, m=3. The arrayed waveguide 266 includes n waveguides.

[0056] The output ends of the plurality of input waveguides 262_1 to 262_m are coupled to different positions of the input slab waveguide 264. The AWG 260A is configured to selectively input the wideband pulsed light L1a to any one of the plurality of input waveguides 262_1 to 262_m. The rest of the configuration is the same as that of the AWG 222 in FIG. 1. The selection of the input waveguide 262 may be realized, for example, by shifting the position of the focal point of the lens 224. Alternatively, a fiber for path switching may be provided between the lens 224 and the AWG 260A, and the wideband pulsed light L1a may be input to one end of the fiber, and the other end of the fiber may be configured to be selectively coupled to any one of the input waveguides 262_1 to 262_m.

[0057] 6 is a diagram for explaining the spectral characteristics of the AWG 260A according to the first embodiment. Here, the number of channels n is 64. φ1 indicates the spectral characteristics when the wideband pulsed light L1a is incident on the incident waveguide 262_1, φ2 indicates the spectral characteristics when the wideband pulsed light L1a is incident on the incident waveguide 262_2, and φ3 indicates the spectral characteristics when the wideband pulsed light L1a is incident on the incident waveguide 262_3. In each of the states φ1 to φ3, the interval X between the central wavelengths λ of adjacent channels is substantially constant. When the incident waveguide 262 is switched, the central wavelengths λ of each channel Chi i are shifted substantially equally by Y. This Y is the adjustment width in this embodiment.

[0058] FIG. 7 shows the change in the central wavelength λ of each of the channels Ch1 to Ch64 when the incident position with respect to the incident slab waveguide 264 is shifted by 10 nm. 1 ~λ 64 In this case, the central wavelength λ 1 ~λ 64 It can be seen that the shift is uniformly Y=6.9 nm.

[0059] FIG. 8 is a diagram for explaining the selection of the input waveguide 262. FIG. 8 shows the wavelengths of the split beams in the states φ1 to φ3 for one channel Chi. The upper row shows the design values ​​of the spectral characteristics of the AWG 260A, and the lower row shows the actual spectral characteristics of the AWG 260A. For example, the AWG 260A has a center wavelength of the design value λ i(REF) It is designed to be.

[0060] Due to manufacturing variations in the AWG260A, the actual wavelength λ i is the design value λ i(REF) In this example, the wavelength shifts from Δλ i , shifted. Δλ i When ≈Y, the state φ3, i.e., the input waveguide 262_3, is selected to set the central wavelength λ of the output waveguide 270_i of this channel Chi. i The design value λ i(REF)This makes it possible to reduce the influence of manufacturing variations.

[0061] Next, an experiment carried out on the light measurement device 100 will be described.

[0062] Using an optical measurement device equipped with an AWG (reference AWG) with certain spectroscopic characteristics (called reference characteristics), a calibration curve was created using multivariate analysis for a sample containing a certain target component, and quantitative measurements were performed. Here, five samples each with three concentrations of the target component (89%, 97%, 106%) were measured. The number of channels was 64, the spectroscopic wavelength range was 900nm to 1300nm, and the wavenumber interval between channels was 54cm. -1 It is.

[0063] Figure 9 shows the measurement results using the standard AWG. The concentration of the measurement target component was estimated with high accuracy.

[0064] Next, the spectral characteristics were replaced with three AWGs (referred to as alternative AWGs) whose central wavelengths were shifted by 0.19 nm, 0.69 nm, and 1.01 nm from the reference characteristics, and quantitative measurements were performed using the calibration curve obtained for the reference AWG. The central wavelength shift (central wavelength difference) was calculated as the average central wavelength of the split beams of each of the 64 channels.

[0065] Figure 10 shows the measurement results when three alternative AWGs were used. It can be seen from Figure 10 that the difference from the estimated value using the reference AWG increases as the central wavelength difference increases. Specifically, the error is 0.5% or less for the alternative AWG (No. 1) with a central wavelength difference of 0.19 nm, but the error is a maximum of 2.8% for the alternative AWG (No. 2) with a central wavelength difference of 0.69 nm, and a maximum of 3.5% for the alternative AWG (No. 3) with a central wavelength difference of 1.01 nm. Therefore, in the past, in order to reduce the error, it was necessary to create a calibration curve again for each AWG using multivariate analysis.

[0066] In contrast, when the light source device 200A including the AWG 260A according to the embodiment is used, the variation in the center wavelength of the AWG 260A can be reduced, thereby improving the measurement accuracy of the light measurement device 100.

[0067] (Embodiment 2) From the measurement result of FIG. 10, if it is desired to suppress the measurement error of the optical measurement device 100 to 0.5% or less, it is necessary to suppress the error of the central wavelength of the AWG to 0.19 nm or less. Referring to FIG. 7, when the incident position of the light to the incident slab waveguide 264 is shifted by 10 nm, the wavelength shift amount Y becomes 6.9 nm. Since the shift width of the incident position and the wavelength shift amount Y are approximately proportional, in order to suppress the error of the central wavelength to 0.19 nm or less, it is necessary to control the incident position of the incident slab waveguide 264 with an accuracy of 0.28 nm. On the other hand, in order to increase the waveguiding efficiency of the incident waveguide 262 to a certain degree, the width of the incident waveguide 262 is required to be 6 nm. In other words, it is not possible to form a plurality of incident waveguides 262 with a center distance of 0.28 nm.

[0068] 11 is a diagram showing a light source device 200B according to embodiment 2. In the AWG 260B, the intervals between the incident waveguides 262_1 to 262_3 are wider than those in embodiment 1, and the shift amount Z of the central wavelength caused by switching the incident waveguide 262 is wider than the interval X between the central wavelengths of adjacent channels. Specifically, when the adjustment amount of the central wavelength caused by switching the incident waveguide 262 is Y, the relationship Z=Y+X holds.

[0069] In the second embodiment, the number of output waveguides 270 is greater than the number n of channels. Specifically, in addition to the n output waveguides 270_1 to 270_n, two more output waveguides 270_0 and 270_n+1 are provided.

[0070] The AWG 260B is configured to be able to change a plurality of output waveguides 270 to which the plurality of fibers 230_1 to 230_n should be connected, depending on the input waveguide 262 into which the wideband pulsed light L1a is input.

[0071] Light source device 200B can operate in three states. First state φ1 The wideband pulsed light L1a is input to the input waveguide 262_1. The fibers 230_1 to 230_n are connected to the output waveguides 270_0 to 270_n-1.

[0072] Second state φ2 The wideband pulsed light L1a is input to the input waveguide 262_2. The fibers 230_1 to 230_n are connected to the output waveguides 270_1 to 270_n.

[0073] Third state φ3 The wideband pulsed light L1a is input to the input waveguide 262_3. The fibers 230_1 to 230_n are connected to the output waveguides 270_2 to 270_n+1.

[0074] 12 is a diagram for explaining the spectral characteristics of the AWG 260 according to the second embodiment. Here, the number of channels n is 64. φ1 indicates the spectral characteristics when the wideband pulsed light L1a is incident on the incident waveguide 262_1, φ2 indicates the spectral characteristics when the wideband pulsed light L1a is incident on the incident waveguide 262_2, and φ3 indicates the spectral characteristics when the wideband pulsed light L1a is incident on the incident waveguide 262_3. In each of the states φ1 to φ3, the interval X between the central wavelengths λ of adjacent channels is substantially constant. When the incident waveguide 262 is switched, the central wavelengths λ of the channels Chi i are shifted substantially equally by Z=Y+X, where Y corresponds to the accommodation amplitude in embodiment 1.

[0075] That is, when the input waveguide 262 is shifted by one, a beam whose center wavelength is shifted by Y is output from the adjacent channel. According to this channel shift, the output waveguide 270 to which the multiple fibers 230_1 to 230_n are connected is selected.

[0076] According to the second embodiment, by designing the multiple incident waveguides 262_1 to 262_3 so as to satisfy the relationship Z=Y+X, it is possible to design Y to be small while increasing the offset width of the incident waveguides 262.

[0077] In the embodiment, the case where m=3 has been described, but the present disclosure is not limited to this, and m may be 2, m=4, m=5, or m≧6.

[0078] Although the embodiments according to the present disclosure have been described using specific terms, this description is merely an example for facilitating understanding and does not limit the scope of the present disclosure or the claims. The scope of the present invention is defined by the claims, and therefore, embodiments, examples, and modifications not described herein are also included in the scope of the present invention. [Explanation of symbols]

[0079] 100 Light measuring device 300 Photodetector 400 Processing unit 200 Light source device 210 Pulsed Light Source 220 divider 224 Lens 230 Fiber 232 Fiber Array 240 Coupler 242 AWG 250 Coupler 260 AWG 262 Input waveguide 264 Incident slab waveguide 266 Arrayed Waveguide 268 Output slab waveguide 270 Output waveguide L1 wavelength swept light L2 object light L3 Reference beam L1a broadband pulsed light

Claims

1. A light source device that generates wavelength swept light, A pulsed light source that generates pulsed light; an arrayed-waveguide diffraction grating that spatially divides the pulsed light according to wavelengths and emits a plurality of divided beams; a plurality of fibers for imparting different delays to the plurality of split beams; a coupler for spatially combining a plurality of beams output from the plurality of fibers; Equipped with The arrayed waveguide grating comprises: A plurality of input waveguides; A plurality of output waveguides; a light source device configured to selectively input the pulsed light to one of the plurality of input waveguides.

2. the wavelength interval between the central wavelengths of the split beams output from the plurality of output waveguides is X; 2. The light source device according to claim 1, wherein the arrayed waveguide diffraction grating is configured such that, when an input waveguide into which the pulsed light is incident is shifted by one, the wavelengths of the divided beams output from each output waveguide are shifted by Y+X.

3. the number of the plurality of output waveguides is greater than the number of the plurality of fibers; 3. The light source device according to claim 2, wherein the plurality of output waveguides to which the plurality of fibers should be connected can be changed according to an input waveguide into which the pulsed light is input.

4. 4. The light source device according to claim 1, wherein the number of the input waveguides is three or more.

5. 4. The light source device according to claim 1, wherein the pulsed light has a wavelength in the range of 900 to 1300 nm.

6. The material of the arrayed waveguide grating is SiO ２ 4. The light source device according to claim 1, wherein:

7. 4. The light source device according to claim 1, wherein the coupler is an arrayed waveguide grating.

8. A light source device according to any one of claims 1 to 3 that generates wavelength swept light; a light receiving device for measuring an object light obtained by irradiating an object with the wavelength swept light; A light measurement device comprising:

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