Improved array waveguide grating spectrometer chip

Abstract

The invention discloses an improved array waveguide grating spectrometer chip. Comprising a substrate, and an input waveguide, a free propagation block waveguide and a waveguide array which are arranged on the substrate, and the waveguide array is mainly formed by arranging a plurality of output waveguides at intervals in an array; the input waveguide, the free propagation block waveguide and the output waveguide are sequentially arranged along the propagation direction of light; the input end and the output end of the input waveguide are respectively coupled with the input ends of the light source and the free propagation block waveguide, the output end of the free propagation block waveguide is respectively coupled with the input ends of the plurality of output waveguides, and the output light of the output end of each output waveguide is irradiated on a detector plane. The inclination angle of the output light beams of the output waveguides improves the overlapping degree of the output waveguides between diffraction fields at the plane of the detector, so that the focusing function and the dispersion function of the output light beams are achieved, and meanwhile the intensity, the resolution ratio and the contrast ratio of the spectrum are enhanced.

Description

Technical Field

[0001] The invention belongs to the field of integrated optics, spectrum analysis and imaging spectrometers, and in particular relates to an improved array waveguide grating spectrometer chip. Background Art

[0002] Since Newton discovered the dispersion phenomenon of the prism, spectrometer technology has begun to develop rapidly. Traditional spectrometers require multiple precision optical components such as slits, collimation, dispersion, and focusing, so they have complex structures, large volumes, and high difficulty in alignment. With the development of integrated optical technology, on-chip integrated spectrometer chips have begun to emerge, solving the problems of large volume and high difficulty in alignment. So far, researchers have conducted in-depth research on a series of on-chip integrated spectrometers based on integrated optical technology, such as arrayed waveguide gratings, etched diffraction gratings, and Fourier spectrometers. Among them, arrayed waveguide gratings have received widespread attention due to their advantages in high spectral resolution and insertion loss.

[0003] Arrayed waveguide gratings were first widely used in the field of optical communications to achieve wavelength multiplexing and demultiplexing, greatly improving communication efficiency. Arrayed waveguide gratings are also used in astronomy. Because the arrayed waveguide gratings used in the field of communications have a fixed wavelength interval between the output channels, continuous spectrum analysis cannot be achieved. Therefore, it is necessary to remove the second beam free propagation area of ​​the arrayed waveguide grating and the waveguide of the subsequent output channel, and directly guide the light in the waveguide array to the free space, and then converge it to the optical camera through a convex lens. Although this structure adopts on-chip integration, the use of lenses makes its volume still very large and still requires precise alignment. The prior art proposes to integrate the focusing function of the lens into the arrayed waveguide grating. The specific approach is to superimpose a length on the basis of the array waveguide length design to meet the wavelength separation. The superimposed waveguide length between each channel just meets the phase condition of the convex lens focusing, so as to achieve the functions of dispersion and focusing.

[0004] The structure proposed in the prior art successfully reduces the size of the device and improves the stability of the system. However, because the output waveguides are parallel to each other, there is a disadvantage that the diffraction field centers of each array waveguide do not overlap. The non-overlapping diffraction field centers will lead to a poor coherence effect, a decrease in spectral intensity, and a decrease in resolution. Especially in the case of a short focal length or a large number of array waveguides, the non-overlapping diffraction field centers will lead to an increase in spectral background light and a decrease in resolution. In astronomical observations, a short focal length and a large number of array waveguides are required to reduce transmission losses and improve the dispersion ability of the grating. Summary of the invention

[0005] In view of the deficiencies in the background technology, the present invention proposes an improved arrayed waveguide grating spectrometer chip.

[0006] The technical solution of the present invention is as follows:

[0007] The invention comprises a substrate, an input waveguide, a free propagation block waveguide and a waveguide array arranged on the substrate, wherein the waveguide array is mainly composed of a plurality of output waveguides arranged in an array at intervals; the input waveguide, the free propagation block waveguide and the output waveguide are arranged in sequence along the propagation direction of light; the input end and the output end of the input waveguide are coupled and connected with the light source and the input end of the free propagation block waveguide respectively, the output end of the free propagation block waveguide is coupled and connected with the input ends of a plurality of output waveguides respectively, and the output light of the output end of each output waveguide is irradiated on the detector plane.

[0008] The angles of the output ends of the output waveguides are different from each other.

[0009] The material of the substrate is glass, silicon nitride, lithium niobate, gallium arsenide, indium phosphide or silicon.

[0010] The output end of the free propagation block waveguide is a circular arc end face.

[0011] The output waveguide is a curved waveguide or a zigzag waveguide.

[0012] The tangent direction of the output end of the free propagation block waveguide is not parallel to the output end of each output waveguide.

[0013] The lengths of the plurality of output waveguides are increased in sequence.

[0014] The lengths of the plurality of output waveguides are set according to the following formula:

[0015] l i =P i -P1+(i-1)ΔL+l1

[0016]

[0017] Among them, l i is the length of the i-th output waveguide, l1 is the length of the first output waveguide, i is the index, P i -P1 is the optical path difference that the i-th output waveguide needs to satisfy relative to the first output waveguide to realize the convex lens focusing function, ΔL is the length difference that needs to be satisfied between adjacent output waveguides to realize the dispersion function, m is the spectral order of the improved arrayed waveguide grating spectrometer chip, λ c is the central wavelength of the improved arrayed waveguide grating spectrometer chip, P i is the focal length f minus the distance from the interference surface formed by the light emitted by the i-th output waveguide to the detector plane, P1 is the focal length f minus the distance from the interference surface formed by the light emitted by the first output waveguide to the detector plane, n eff is the effective refractive index of the core of the output waveguide, f is the focal length, D iis the distance from the output end of the i-th output waveguide to the center output waveguide.

[0018] The central output waveguide is the middlemost output waveguide among all the output waveguides 4 .

[0019] The angle of the output end of the output waveguide is set according to the following formula:

[0020]

[0021] Among them, γ i is the angle between the light output from the output end of the output waveguide and the horizontal direction, arcsin is the inverse cosine trigonometric function, arctan is the inverse sine trigonometric function, sin() is the sine trigonometric function, f is the focal length, n eff is the effective refractive index of the core of the output waveguide, D i is the distance from the output end of the i-th output waveguide to the center output waveguide.

[0022] The angle of the output end of the output waveguide is the angle between the light output from the output end of the output waveguide and the horizontal direction, and the horizontal direction is a direction perpendicular to the detector plane.

[0023] The distance D from the output end of the i-th output waveguide to the center output waveguide i Set it according to the following formula:

[0024]

[0025] Wherein, d is the distance between the output ends of two adjacent output waveguides, and N is the number of output waveguides.

[0026] The innovation of the present invention lies in designing the angle of the output end of the output waveguide and the length of the output waveguide to meet the phase condition, so that the light output by the output waveguide can be focused on the detector plane, while achieving the beneficial effects of enhancing spectral intensity, resolution and contrast and reducing crosstalk.

[0027] The beneficial effects of the present invention are:

[0028] The tilt angle of the output light beams of each output waveguide in the present invention increases the overlap between the diffraction fields of each output waveguide at the detector plane, so that the present invention can enhance the intensity, resolution and contrast of the spectrum while realizing the focusing and dispersion functions of the output light beams. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 (a) is a schematic diagram of the improved arrayed waveguide grating spectrometer chip of the present invention;

[0030] Figure 1(b) is a schematic diagram of the output end of the output waveguide of the present invention;

[0031] Figure 1 (c) is a demonstration diagram of the present invention in which the centers of the diffraction fields overlap by changing the structure when the two outermost output waveguides and the middle output waveguide are sequentially passed with light;

[0032] Figure 2 This is a diagram of the light field intensity after the light propagates through the free propagation block waveguide in Example 2 of the present invention;

[0033] Figure 3 This is a schematic diagram illustrating the structure of the improved arrayed waveguide grating spectrometer chip in Example 2 of the present invention;

[0034] Figure 4 This is a simulation spectrum diagram in Example 2 of the present invention;

[0035] Figure 5 This is a simulated spectrum diagram in comparative example 1 of the present invention. DETAILED DESCRIPTION

[0036] The present invention is described in more detail below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited thereto. For those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field.

[0037] like Figure 1 As shown in (a), the improved arrayed waveguide grating spectrometer chip of embodiment 1 of the present invention comprises:

[0038] A substrate 1 and an input waveguide 2, a free propagation block waveguide 3 and a waveguide array arranged on the substrate 1, wherein the waveguide array is mainly composed of a plurality of output waveguides 4 arranged in an array at intervals; the input waveguide 2, the free propagation block waveguide 3 and the output waveguide 4 are arranged in sequence along the propagation direction of light; the input end and the output end of the input waveguide 2 are coupled and connected to an external light source and the input end of the free propagation block waveguide 3 respectively, the output end of the free propagation block waveguide 3 is coupled and connected to the input ends of a plurality of output waveguides 4 respectively, and the output light of the output end of each output waveguide 4 is irradiated on an external detector plane.

[0039] The angles of the output ends of the output waveguides 4 are different from each other.

[0040] like Figure 1 (b) is a schematic diagram showing the output end of the output waveguide of this embodiment.

[0041] like Figure 1(c) is a demonstration diagram showing that when the two outermost output waveguides and the middle output waveguide of the present invention pass light in sequence, the center of the diffraction field is overlapped by changing the structure.

[0042] The light source emits light, which is coupled with the input end of the input waveguide 2 after propagating through the optical fiber, enters the input waveguide 2 for propagation, propagates through the free propagation block waveguide 3, reaches the input end of the output waveguide 4, and is then output from the output end of the output waveguide 4 to illuminate the detector plane.

[0043] The free propagation block waveguide 3 is the free propagation area of ​​the light beam in the spectrometer.

[0044] Several output waveguides 4 form a waveguide array.

[0045] In a specific implementation, the end face of the input end of the input waveguide 2 is flush with one end face of the substrate 1 , and the end face of the output end of each output waveguide 4 is flush with the other end face of the substrate 1 .

[0046] The material of the substrate 1 is glass, silicon nitride, lithium niobate, gallium arsenide, indium phosphide or silicon.

[0047] The output end of the free propagation block waveguide 3 is a circular arc end face.

[0048] The output waveguide 4 is a curved waveguide or a zigzag waveguide.

[0049] The tangent direction of the output end of the free propagation block waveguide 3 is not parallel to the output end of each output waveguide 4 .

[0050] The lengths of the plurality of output waveguides 4 increase in sequence.

[0051] The lengths of the output waveguides 4 are set according to the following formula:

[0052] l i =P i -P1+(i-1)ΔL+l1

[0053]

[0054] Among them, l i is the length of the i-th output waveguide 4, l1 is the length of the first output waveguide 4, i is the index, P i -P1 is the optical path difference that the i-th output waveguide 4 needs to satisfy relative to the first output waveguide 4 to realize the convex lens focusing function, ΔL is the length difference that needs to be satisfied between adjacent output waveguides 4 to realize the dispersion function), m is the spectral order of the improved arrayed waveguide grating spectrometer chip, λ c is the central wavelength of the improved arrayed waveguide grating spectrometer chip, P iis the focal length f minus the distance from the light emitted by the i-th output waveguide 4 to the detector plane to form the interference surface, P1 is the focal length f minus the distance from the light emitted by the first output waveguide 4 to the detector plane to form the interference surface, n eff is the effective refractive index of the core of the output waveguide 4, f is the focal length, and D i is the distance from the output end of the i-th output waveguide 4 to the center output waveguide.

[0055] The focal length f is the focal length required for the detector plane to achieve exact focusing.

[0056] The central output waveguide 4 is the output waveguide 4 in the middle of all the output waveguides 4 .

[0057] The focusing function of the convex lens is realized so that the output waveguide 4 can be focused exactly on the detector plane.

[0058] The angle of the output end of the output waveguide 4 is set according to the following formula:

[0059]

[0060] Among them, λ i is the angle between the light output from the output end of the output waveguide 4 and the horizontal direction, arcsin is the inverse cosine trigonometric function, arctan is the inverse sine trigonometric function, sin() is the sine trigonometric function, f is the focal length, n is eff is the effective refractive index of the core of the output waveguide 4, D i The output end of the i-th output waveguide 4 is connected to D i is the distance from the output end of the i-th output waveguide 4 to the center output waveguide.

[0061] The angle of the output end of the output waveguide 4 is the angle between the light output from the output end of the output waveguide 4 and the horizontal direction, and the horizontal direction is a direction perpendicular to the detector plane.

[0062] The distance D from the output end of the i-th output waveguide 4 to the center output waveguide 4 i Set it according to the following formula:

[0063]

[0064] Wherein, d is the distance between the output ends of two adjacent output waveguides 4 , and N is the number of output waveguides 4 .

[0065] Example 2

[0066] S1. Design of free propagation block waveguide 3.

[0067] The arc radius R0 of the output end of the free propagation block waveguide 3 is selected to be 6000 μm, and the central wavelength λ of the improved arrayed waveguide grating spectrometer isc =1.550μm, requiring that when the light beam is transmitted through the input waveguide and enters the free propagation block waveguide 3 and reaches the input end face of the output waveguide 4, its optical field width should be smaller than the width of the input end face. For the transmission mode of the output waveguide 4, its transverse and longitudinal half-maximum full width (FWHM) are:

[0068] ω L =dx(2ln2) 1 / 2 (0.321+2.1W -3 / 2 +4W -6 )

[0069] ω T =dy(2ln2) 1 / 2 (0.321+2.1D -3 / 2 +4D -6 )

[0070]

[0071] Among them, ω L is the lateral full width at half maximum of the transmission mode of output waveguide 4, ω T is the longitudinal half-maximum full width of the transmission mode of the output waveguide 4, k0 represents the wave number, W is called the transverse normalized frequency of the optical waveguide, D is called the longitudinal normalized frequency of the optical waveguide, dx, dy are the transverse width and longitudinal height of the core of the output waveguide 4, and n1, n2 are the core refractive index and cladding refractive index of the output waveguide 4, n eff is the effective refractive index of the fiber core. After a propagation distance of R0, the field distribution at R0 is:

[0072]

[0073] Among them, E i () represents the field distribution at R0, α represents the product of wavelength and focal length in Fourier optical propagation, λ represents the wavelength of the propagating light wave, and x ′ Represents the coordinates at R0.

[0074] Calculate the x corresponding to the function value where the function value drops to 1 / e of the maximum value ′ Thus, the 1 / e width can be calculated. In the example provided by the present invention, the width of the output waveguide 4 is 6.1 microns. For light with a wavelength of 1550 nanometers, the refractive indices of the core layer and the cladding layer are 1.4548 and 1.4440, respectively. f = 6000, λ = 1.550 μm, the field distribution of the TE mode is as follows Figure 2As shown, its 1 / e width is 375.1920 microns, and its optical field width is equal to twice the 1 / e width, which is 750.3840 microns. Therefore, the chord length of the arc end of the free propagation block waveguide 3 is selected to be 1750 microns, the spacing D0 between the input ends of each output waveguide 4 on the arc end surface of the light beam free propagation block waveguide 3 is 12 microns, and the number of output waveguides 4 is 120.

[0075] S2. Design the waveguide array of the improved array waveguide grating spectrometer chip.

[0076] The lengths of several output waveguides 4 in the S21 waveguide array satisfy the relationship.

[0077] For the improved arrayed waveguide grating spectrometer chip, it is necessary to realize the dispersion function on the basis of realizing the output beam focusing function. Therefore, the length of the output waveguide 4 needs to meet the following requirements:

[0078] l i -l1=P i -P1+(i-1)ΔL

[0079]

[0080] Among them, l i is the length of the i-th output waveguide 4, l1 is the length of the first output waveguide 4, i is the index, P i -P1 is the optical path difference that the i-th output waveguide 4 needs to satisfy relative to the first output waveguide 4 to realize the convex lens focusing function, ΔL is the length difference that needs to be satisfied between adjacent output waveguides 4 to realize the dispersion function, m is the spectral order of the improved arrayed waveguide grating spectrometer chip, λ c is the central wavelength of the improved arrayed waveguide grating spectrometer chip, P i is the focal length f minus the distance from the light emitted by the i-th output waveguide 4 to the detector plane to form the interference surface, P1 is the focal length f minus the distance from the light emitted by the first output waveguide 4 to the detector plane to form the interference surface, n eff is the effective refractive index of the core of the output waveguide 4, f is the focal length, and D i is the distance from the output end of the i-th output waveguide 4 to the central output waveguide, d is the distance between the output ends of two adjacent output waveguides 4, and N is the number of output waveguides 4.

[0081] The distance d between the output ends of two adjacent output waveguides 4 is selected to be 70 microns, and the focal length f is 70 microns, thereby determining the length P of the i-th output waveguide 4 used by each output waveguide 4 to realize the detector plane focusing function. i The length difference ΔL between adjacent output waveguides 4 and the free spectral range FSR of the improved arrayed waveguide grating spectrometer chip satisfy the following relationship:

[0082]

[0083] Where FSR is the free spectral range, c0 is the speed of light in vacuum, and n g is the group refractive index, satisfying the following relationship:

[0084]

[0085] The length difference ΔL between adjacent output waveguides 4 is finally selected to be 42.71919 microns.

[0086] S3. Design the angle of the output end of the output waveguide 4.

[0087] Define the angle γ between the light output from the output end of the i-th output waveguide 4 and the horizontal direction i The horizontal direction is perpendicular to the detector plane, γ i The expression is:

[0088]

[0089] The calculated D i By substituting this formula into the equation, the angle between the light output from the output end of each output waveguide 4 and the horizontal direction can be calculated.

[0090] The light field intensity of the light in this embodiment after propagating through the free propagation block waveguide 3 is shown in FIG. Figure 2 shown.

[0091] S4, geometric design of output waveguide 4 of array waveguide grating spectrometer.

[0092] S41, structure of the array waveguide grating spectrometer output waveguide 4 device.

[0093] like Figure 3 As shown, the center of the free propagation block waveguide 3 is defined as the coordinate origin, the horizontal direction is the x-axis direction, and the vertical direction is the y-axis direction; the horizontal direction is the direction perpendicular to the detector plane.

[0094] The angle between the line segment formed by connecting the midpoint of the arc end surface of the free propagation block waveguide 3 and the coordinate origin and the x-axis is θ, the angle between the line segment formed by connecting the midpoint of the arc end surface of the free propagation block waveguide 3 and the coordinate origin and the radius formed by the center of the input end of the first output waveguide 4 and the coordinate origin is α1, and the angle between the line segment formed by connecting the midpoint of the arc end surface of the free propagation block waveguide 3 and the coordinate origin and the radius formed by the center of the input end of the i-th output waveguide 4 and the coordinate origin is α i, the length of the line segment formed by connecting the point on the arc end surface of the free propagation block waveguide 3 and the coordinate origin is defined as L0, the line segment formed by connecting the midpoint of the arc end surface of the free propagation block waveguide 3 and the coordinate origin is defined as the rotation axis, the coordinate origin is the rotation center, and the α obtained by counterclockwise rotation is i Taking a negative value, the α obtained by rotating clockwise i The value is positive.

[0095] The first output waveguide 4 is composed of a straight waveguide 1, an arc waveguide and a straight waveguide 2 connected in sequence: Straight waveguide 1: a waveguide between two points R0 and R0+L0+L1 on a straight line passing through the center of the arc end face of the free propagation block waveguide 3 and the angle between the straight line and the x-axis is θ-α1, that is, the length of the straight waveguide 1 is L1. Arc waveguide: a waveguide with a center angle of θ-α1+γ1 and a radius of R1. Straight waveguide 2: a waveguide with a length of K1 and an inclination angle of γ1.

[0096] The i-th output waveguide 4 is composed of a straight waveguide 1, an arc waveguide and a straight waveguide 2 connected in sequence: Straight waveguide 1: passes through the center of the arc end face of the free propagation block waveguide 3, and the angle between it and the x-axis is θ-α i The distance between the straight line and the center of the circle is R0 and R0+L0+L i The length of the waveguide between the two points, that is, the straight waveguide, is L i Circular waveguide: the center angle is θ-α i +γ i , with a radius of R i Straight waveguide 2: length is K i , the inclination angle is γ i of waveguide.

[0097] The Nth output waveguide 4 is composed of a straight waveguide 1, an arc waveguide and a straight waveguide 2 connected in sequence: Straight waveguide 1: passes through the center of the arc end face of the free propagation block waveguide 3, and has an angle of θ-α with the x-axis N The distance between the straight line and the center of the circle is R0 and R0+L0+L N The length of the waveguide between the two points, that is, the straight waveguide, is L N Circular waveguide: the center angle is θ-α N +γ N , with a radius of R N Straight waveguide 2: length is K N , the inclination angle is γ N of waveguide.

[0098] The following relationship needs to be satisfied between the output waveguides 4:

[0099] The length of the i-th output waveguide 4 needs to satisfy l i -l1=P i -P1+(i-1)ΔL, so:

[0100] L i +(θ-α i +γ i )R i +K i -[L1+(θ-α1+γ1)R1+K1]=l i -l1

[0101] The output ends of the output waveguides 4 should be located on the same output end face, so:

[0102] (R0+L0+L i )cos(θ-α i )+R i sin(θ-α i )+R i sin(γ i )+K i cos(γ i )

[0103] -[(R0+L0+L1)cos(θ-α1)+R1 sin(θ-α1)+R1 sin(γ1)

[0104] +K1 cos(γ1)]=0

[0105] The spacing between the output ends of adjacent output waveguides 4 on the y-axis is equal, both d, so:

[0106] (R0+L0+L i )sin(θ-α i )+R i cos(γ i )-R i cos(θ-α i )-K i sin(γ i )

[0107] -[(R0+L0+L1)sin(θ-α1)-R1 cos(θ-α1)+R1 cos(γ1)

[0108] -K1 sin(γ1)]=(i-1)d

[0109] remember:

[0110] a s =θ-α i +γ i

[0111] b s = l i-l1+L1+(θ-α1+γ1)R1+K1

[0112] c s =(R0+L0+L1)cos(θ-α1)+R1 sin(θ-α1)+R1 sin(γ1)

[0113] +K1 cos(γ1)-(R0+L0)cos(θ-α i )

[0114] d s =(R0+L0+L1)sin(θ-α1)-R1 cos(θ-α1)+R1 cos(γ1)

[0115] +K1 sin(γ1)-(R0+L0)sin(θ-α i )+(i

[0116] -1)d

[0117] De=[cos(θ-α i )-cos(γ i )]·[-cos(θ-α i )+cos(γ i )

[0118] +a s sin(γ1)]-[sin(θ-α i )+sin(γ i )]

[0119] ·[sin(θ-α) i )+sin(γ i )-a s cos(γ i )]

[0120] Nu1=[c s -b s cos(γ i )]·[-cos(θ-α i )+cos(γ i )+a s sin(γ1)]

[0121] -[b s sin(γ i )+d s ]·[sin(θ-α i )+sin(γ i )

[0122] -a s cos(γ i )]

[0123] Nu2 = b s [cos(θ - α i )sin(γ i ) + sin(θ - α i )cos(γ i )]

[0124] -c s [sin(θ - α i ) + sin(γ i )] + d s [cos(θ - α i )

[0125] -cos(γ i )]

[0126] Nu3 = b s [-cos 2 (θ - α i ) - sin 2 (θ - α i ) - sin(θ - α i )sin(γ i )

[0127] +cos(θ - α i )cos(γ i )]

[0128] +c s [cos(θ - α i ) - cos(γ i ) - a s sin(θ - α i )]

[0129] +d s [sin(θ - α i ) + sin(γ i ) - a s cos(θ - α i )]

[0130] Thus, the solution is:

[0131]

[0132] In the above formula, a s , b s , c s , d s , De, Nu1, Nu2, and Nu3 have no specific meaning and are only used for convenient calculation.

[0133] S43. Selection and optimization of the initial value.

[0134] In this example, the parameters to be optimized are L1, R1, K1, and θ. After the parameters of the first output waveguide 4 are determined, the parameters of the subsequent output waveguides 4 can be calculated using the above formula. The scanning range of L1 is 0 to 3000 microns, the scanning range of R1 is 5000 to 50000 microns, the scanning range of K1 is 0 to 3000 microns, and the scanning range of θ is The minimum value of γ1 is to ensure the consistency of the arc orientation of the output waveguide 4. Table 1 shows the optimized parameter values. Substituting the optimized result into the above L i ,R i ,K i The calculation formula can be used to calculate the parameters of each output waveguide 4, and then according to the calculated parameters of each output waveguide 4, as shown in Table 1, a specific example of the improved arrayed waveguide grating spectrometer is produced, and its schematic diagram is shown in Figure 3 shown.

[0135] Table 1 Parameters of improved arrayed waveguide grating spectrometer

[0136] <![CDATA[R0]]> 6000μm ΔL 42.7192μm N 120 <![CDATA[L1]]> 0 <![CDATA[D0]]> 12μm <![CDATA[R1]]> 29206.5669μm d 70μm <![CDATA[K1]]> 3000μm f 50000μm θ 0.7461446

[0137] The spectrum obtained by simulation in Example 2 is as follows Figure 4 shown.

[0138] Comparative Example 1

[0139] The same parameters as in Example 2 are used, and only the output angles of all output waveguides 4 are changed to be horizontal. The spectrum obtained by simulation is as follows: Figure 5 shown.

[0140] Figure 5 and Figure 4 The spectrum diagrams obtained by simulating the arrayed waveguide grating spectrometer in comparative example 1 of the prior art and the improved arrayed waveguide grating spectrometer in embodiment 2 proposed by the present invention are respectively shown. The horizontal axis in the figure indicates the wavelength corresponding to the light spot, and the vertical axis indicates the normalized intensity. The illustrations all indicate the spectrum diagram of light with a wavelength of 1550 nanometers, that is, the central wavelength. The coordinates of the vertical dotted line on the x-axis in the illustrations indicate the wavelength corresponding to when the light field intensity drops to 1 / e of the maximum value, and the wavelength interval set by the simulation is 0.5 nanometers. According to the simulation results, the intensity of the spectral stripes, the 1 / e width of the light field, and the crosstalk in the two cases are calculated, and the comparison results are obtained as follows: Under this set of parameters, compared with the arrayed waveguide grating spectrometer in the prior art, the stripe intensity of the spectrum of the improved arrayed waveguide grating spectrometer proposed by the present invention is increased by 99.96%, the 1 / e width of the stripes is reduced by 18.78%, and the crosstalk is reduced by 140.94%. While improving the stripe brightness of the spectrum, the resolution and contrast of the stripes are improved.

[0141] The innovation of the present invention lies in designing the angle of the output end of the output waveguide and the length of the output waveguide to meet the phase condition, so that the light output by the output waveguide can be focused on the detector plane, while achieving the beneficial effects of enhancing spectral intensity, resolution and contrast and reducing crosstalk.

[0142] Those skilled in the art can understand that the above is only one example of the invention and is not intended to limit the invention. Although the invention is described in detail with reference to the above example, those skilled in the art can still modify the technical solution of the above example or replace some of the technical features with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the invention shall be included in the protection scope of the invention.

Claims

1. An improved arrayed waveguide grating spectrometer chip, characterized in that: The invention comprises a substrate (1), an input waveguide (2), a free propagation block waveguide (3) and a waveguide array arranged on the substrate (1), wherein the waveguide array is mainly composed of a plurality of output waveguides (4) arranged in an array at intervals; the input waveguide (2), the free propagation block waveguide (3) and the output waveguide (4) are arranged in sequence along the propagation direction of light; the input end and the output end of the input waveguide (2) are coupled and connected to a light source and the input end of the free propagation block waveguide (3) respectively, the output end of the free propagation block waveguide (3) is coupled and connected to the input ends of a plurality of output waveguides (4) respectively, and the output light of the output end of each output waveguide (4) is irradiated on the detector plane; The angles of the output ends of the output waveguides (4) are different from each other.

2. The improved arrayed waveguide grating spectrometer chip according to claim 1, characterized in that: The material of the substrate (1) is glass, silicon nitride, lithium niobate, gallium arsenide, indium phosphide or silicon.

3. The improved arrayed waveguide grating spectrometer chip according to claim 1, characterized in that: The output end of the free propagation block waveguide (3) is a circular arc end face.

4. The improved arrayed waveguide grating spectrometer chip according to claim 1, characterized in that: The output waveguide (4) is a curved waveguide or a zigzag waveguide.

5. The improved arrayed waveguide grating spectrometer chip according to claim 1, characterized in that: The tangent direction of the output end of the free propagation block waveguide (3) is not parallel to the output end of each output waveguide (4).

6. The improved arrayed waveguide grating spectrometer chip according to claim 1, characterized in that: The lengths of the plurality of output waveguides (4) increase in sequence.

7. The improved arrayed waveguide grating spectrometer chip according to claim 1, characterized in that: The lengths of the plurality of output waveguides (4) are set according to the following formula: l i =P i -P1+(i-1)ΔL+l1 Among them, l i is the length of the i-th output waveguide (4), l1 is the length of the first output waveguide (4), i is the index, P i -P1 is the optical path difference that needs to be satisfied between the i-th output waveguide (4) and the first output waveguide (4) to realize the convex lens focusing function, ΔL is the length difference that needs to be satisfied between adjacent output waveguides (4) to realize the dispersion function, m is the spectral order of the improved arrayed waveguide grating spectrometer chip, λ c is the central wavelength of the improved arrayed waveguide grating spectrometer chip, P i is the focal length f minus the distance from the light emitted by the i-th output waveguide (4) to the detector plane to form an interference surface, P1 is the focal length f minus the distance from the light emitted by the first output waveguide (4) to the detector plane to form an interference surface, n eff is the effective refractive index of the core of the output waveguide (4), f is the focal length, and D i is the distance from the output end of the i-th output waveguide (4) to the central output waveguide (4).

8. The improved arrayed waveguide grating spectrometer chip according to claim 1, characterized in that: The angle of the output end of the output waveguide (4) is set according to the following formula: Among them, γ i is the angle between the light output from the output end of the output waveguide (4) and the horizontal direction, arcsin is the inverse cosine trigonometric function, arctan is the inverse sine trigonometric function, sin() is the sine trigonometric function, f is the focal length, n is eff is the effective refractive index of the core of the output waveguide (4), D i is the distance from the output end of the i-th output waveguide (4) to the central output waveguide (4).

9. The improved arrayed waveguide grating spectrometer chip according to claim 8, characterized in that: The distance D between the output end of the i-th output waveguide (4) and the central output waveguide (4) is i Set it according to the following formula: Wherein, d is the distance between the output ends of two adjacent output waveguides (4), and N is the number of output waveguides (4).

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