CN106290257A - A kind of integrated waveguide optical biochemical sensor based on spectrum division and method - Google Patents

Abstract

The invention discloses an integrated waveguide optical biochemical sensor based on spectrum splitting, which belongs to the technical field of optical sensing. The sensor is composed of trapezoidal waveguide, unequal-length S-shaped curved waveguide, unequal-width straight waveguide, and multi-mode waveguide connection. The phase difference generated by the propagation of light waves in the upper branch and the lower branch of the sensor has a nonlinear relationship with the wavelength of the light wave. The change of the refractive index of the upper cladding causes the sharp splitting of the output interference light wave power spectrum, which has extremely high sensing sensitivity. The trapezoidal waveguide, S-shaped curved waveguide, straight waveguide and multimode waveguide constituting the sensor are simple in structure and easy to prepare. The sensing demodulation system composed of a wide-spectrum light source and a spectrometer is adopted. The system structure is simple, low in cost, and easy to implement.

Description

An integrated waveguide optical biochemical sensor and method based on spectral splitting

technical field

The invention belongs to the technical field of optical sensing, and in particular relates to an integrated waveguide optical biochemical sensor and method based on spectrum splitting.

Background technique

Optical biochemical sensing technology has broad application prospects in major disease detection, new drug creation, environmental safety monitoring and other fields. The integrated waveguide optical biochemical sensor is based on the optical waveguide microstructure sensing unit, which uses the interaction between the substance to be measured and the light wave, so that some physical parameters of the light wave, such as wavelength, intensity, phase, polarization, etc., change. Measurement to obtain information such as the concentration and category of the substance to be tested has the advantages of less sample required, small volume, and low energy consumption, so it has received great attention. Integrated waveguide optical biochemical sensors based on waveguide grating, waveguide Young's interference structure, waveguide microring and other structures have been reported successively.

Prior art [1] (M.Mendez-Astudillo, H.Takahisa, H.Okayama and H.Nakajima. "Optical refractive index biosensor using evanescently coupled lateral Bragggratings on silicon-on-insulator," Japanese Journal of Applied Physics, 2016 , Vol.55, No.8S3, pp.08RE09), the side-etched Bragg waveguide grating is used as the sensing unit, and the drift characteristic of the Bragg wavelength of the waveguide grating with the change of the refractive index of the upper cladding is used for sensing and detection . Although the sensor has a relatively compact structure, its sensing sensitivity is low.

Prior art [2] (D.Hradetzky, C.Mueller and H.Reinecke. "Interferometric label-free biomolecular detection system," Journal of Optics A: Pure and Applied Optics, 2006, Vol.8, No.7, pp.S360 In –S364), a Young’s interference structure composed of a waveguide coupling grating and a double straight waveguide is used as the sensing unit, and the change of the refractive index of the sample to be measured is obtained by using the change of the Young’s interference fringes. The sensor system uses bulk optics to split the light, which is coupled into and out of the double straight waveguide through the waveguide coupling grating respectively, requiring precise alignment, so the system is bulky and complex in structure.

Prior art [3] (S.-Y.Cho and D.K.Borah. "Chip-scale hybrid optical sensingsystems using digital signal processing," Optics Express, 2009, Vol.17, No.1, pp.150-155) , using an integrated waveguide microring as the sensing unit, and a sensing demodulation system based on a broadband light source, an arrayed waveguide grating and an arrayed photodetector. Although the waveguide microring has a high quality factor, the limited spectral resolution of arrayed waveguide gratings limits the performance of the sensor and increases the difficulty and complexity of the system.

Contents of the invention

The invention aims at the problems of low sensing sensitivity, bulky volume, complex system and the like of the integrated waveguide optical biochemical sensor.

Technical scheme of the present invention:

An integrated waveguide optical biochemical sensor based on spectrum splitting, the integrated waveguide optical biochemical sensor includes trapezoidal waveguide 1, multimode waveguide 1, trapezoidal waveguide 2, trapezoidal waveguide 3, S-shaped curved waveguide 1, S-shaped curved waveguide 2, straight waveguide 1. Straight waveguide 2, S-shaped curved waveguide 3, S-shaped curved waveguide 4, trapezoidal waveguide 4, trapezoidal waveguide 5, multimode waveguide 2 and trapezoidal waveguide 6, trapezoidal waveguide 1 and multimode waveguide 1 connected, trapezoidal waveguide 2, S Type curved waveguide 1, straight waveguide 1, S-shaped curved waveguide 3 and trapezoidal waveguide 4 are connected in sequence, trapezoidal waveguide 3, S-shaped curved waveguide 2, straight waveguide 2, S-shaped curved waveguide 4 and trapezoidal waveguide 5 are connected in sequence, trapezoidal waveguide 2 The trapezoidal waveguide 3 is connected to the multimode waveguide 1 respectively, the trapezoidal waveguide 4 and the trapezoidal waveguide 5 are respectively connected to the multimode waveguide 2, and the multimode waveguide 2 is connected to the trapezoidal waveguide 6. The above-mentioned waveguides are all rectangular waveguides, and the overall connection is a ring.

The trapezoidal waveguide 1, trapezoidal waveguide 2, trapezoidal waveguide 3, S-shaped curved waveguide 1, S-shaped curved waveguide 2, straight waveguide 1, straight waveguide 2, S-shaped curved waveguide 3, S-shaped curved waveguide 4, trapezoidal waveguide 4 , trapezoidal waveguide 5 and trapezoidal waveguide 6 are single-mode waveguides.

The S-shaped curved waveguide 1, S-shaped curved waveguide 2, straight waveguide 2, S-shaped curved waveguide 3 and S-shaped curved waveguide 4 have the same width;

The lengths of the S-bend waveguide 1 and the S-bend waveguide 2 are different;

The lengths of the S-bend waveguide 3 and the S-bend waveguide 4 are different;

The straight waveguide 1 and the straight waveguide 2 have the same length but different widths.

The trapezoidal waveguide 1, the multimode waveguide 1, the trapezoidal waveguide 2 and the trapezoidal waveguide 3 constitute an optical branching structure;

The trapezoidal waveguide 4, the trapezoidal waveguide 5, the multimode waveguide 2 and the trapezoidal waveguide 6 constitute an optical combination structure; the trapezoidal waveguide 2, the S-shaped curved waveguide 1, the straight waveguide 1, the S-shaped curved waveguide 3 and the trapezoidal waveguide 4 The upper branch is formed; the trapezoidal waveguide 3, the S-shaped curved waveguide 2, the straight waveguide 2, the S-shaped curved waveguide 4 and the trapezoidal waveguide 5 constitute the lower branch. The light wave propagates in the upper branch and the lower branch to generate a phase difference, and the phase difference has a nonlinear relationship with the wavelength of the light wave. When the phase difference changes, the output interference light wave power spectrum is sharply split, and the wavelengths of the interference extremes in the spectrum are separated, and the sensor has extremely high sensing sensitivity.

A method of using an integrated waveguide optical biochemical sensor based on spectrum splitting, which performs sensing and detection according to the following steps:

The light wave with a certain spectral width enters the multimode waveguide 1 through the trapezoidal waveguide 1, and is divided into two paths, output by the trapezoidal waveguide 2 and the trapezoidal waveguide 3 respectively, and enters the upper branch and the lower branch; the light wave propagates in the upper branch and the lower branch , the evanescent wave interacts with the solution to be measured in the cladding on the waveguide;

Because the waveguide structures of the upper branch and the lower branch are different, including the length of the S-bend waveguide 1 and the S-bend waveguide 2, the width of the straight waveguide 1 and the straight waveguide 2, the S-bend waveguide 3 and the S-bend waveguide The length of 4 is different, and the light wave propagates in the upper branch and the lower branch to produce a phase difference Expressed as

in is the phase difference between the straight waveguides in the upper branch and the lower branch, is the phase difference of the S-shaped curved waveguide in the upper branch and the lower branch

where L _arm is the length of straight waveguide 1 and straight waveguide 2, n _eff1 (λ) is the effective refractive index of straight waveguide 1, n _eff2 (λ) is straight waveguide 2, S-curved waveguide 1, S-curved waveguide 2, The effective refractive index of S-bend waveguide 3 and S-bend waveguide 4, ΔL _s is the total length of S-bend waveguide 1 and S-bend waveguide 3 in the upper branch and the S-bend waveguide 2 and S-bend waveguide in the lower branch The difference in the total length of the curved waveguide 4;

The light waves in the upper branch and the lower branch enter the multimode waveguide 2 through the trapezoidal waveguide 4 and the trapezoidal waveguide 5 respectively, and output through the trapezoidal waveguide 6 after combining; the light waves in the upper branch and the lower branch interfere during the combining process , the power of the interference light wave output by the trapezoidal waveguide 6(14) is expressed as

Wherein P _in is the light wave power entering the trapezoidal waveguide 1;

When the refractive index of the upper cladding changes, that is, when the concentration of the solution to be measured changes, the effective refractive indices n _eff1 (λ) and n _eff2 (λ) of the waveguide change, causing light waves to propagate in the upper branch and the lower branch resulting phase difference changes happened. Because the phase difference generated by the propagation of the light wave in the upper branch and the lower branch has a nonlinear relationship with the wavelength of the light wave, it will cause a sharp split of the output interference light wave power spectrum, that is, the wavelength of the interference extreme value in the spectrum is separated. By detecting the interference The amount of change of the extreme wavelength can be used to obtain the change amount of the upper cladding refractive index, and then the concentration of the solution to be measured can be obtained.

Beneficial effects of the present invention:

(1) In the integrated waveguide optical biochemical sensor of the present invention, the phase difference generated by the propagation of the light wave in the upper branch and the lower branch has a nonlinear relationship with the wavelength of the light wave, and the change of the refractive index of the upper cladding will cause a sharp change in the power spectrum of the output interference light wave Split, with extremely high sensing sensitivity.

(2) The integrated waveguide optical biochemical sensor of the present invention adopts trapezoidal waveguide, S-shaped curved waveguide, straight waveguide and multi-mode waveguide to form a sensing unit, which has simple structure, convenient preparation and low cost.

(3) The integrated waveguide optical biochemical sensor of the present invention uses a wide-spectrum light source and a spectrometer to form a sensing demodulation system, which has a simple structure, low cost, and is easy to implement.

Description of drawings

Fig. 1 present invention is based on the structural representation of the integrated waveguide optical biochemical sensor of spectrum splitting;

Fig. 2 is an integrated waveguide optical biochemical sensor system based on spectrum splitting according to an embodiment of the present invention;

Figure 3 is a structural diagram of an optical branch composed of a trapezoidal waveguide and a multimode waveguide;

Fig. 4 is the simulation result of light wave propagating in the optical branch structure shown in Fig. 3;

The cross-sectional structure diagram of straight waveguide 1 and straight waveguide 2 in Fig. 5 sensor;

The phase difference of light wave propagation in the two branches of the sensor under the conditions of the solution to be measured with different refractive indices in Fig. 6;

Sensor output spectra under the conditions of solutions to be measured with different refractive indices in Fig. 7;

The corresponding relationship between the amount of change in the refractive index of the solution to be measured and the amount of interference extreme wavelength separation in Fig. 8;

In the figure: 1 trapezoidal waveguide 1; 2 multimode waveguide 1; 3 trapezoidal waveguide 2; 4 trapezoidal waveguide 3; 5S curved waveguide 1; 6S curved waveguide 2; 3; 10S-shaped curved waveguide 4; 11 trapezoidal waveguide 4; 12 trapezoidal waveguide 5; 13 multimode waveguide 2; 14 trapezoidal waveguide 6.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

As shown in Fig. 1, the present invention is based on an integrated waveguide optical biochemical sensor with spectrum splitting. The sensor includes: trapezoidal waveguide 1, multimode waveguide 1, trapezoidal waveguide 2, trapezoidal waveguide 3, S-shaped curved waveguide 1, S-shaped curved waveguide 2, straight waveguide 1, straight waveguide 2, S-shaped curved waveguide 3, S-shaped curved waveguide The waveguide 4, the trapezoidal waveguide 4, the trapezoidal waveguide 5, the multimode waveguide 2 and the trapezoidal waveguide 6, all of which are rectangular waveguides, are connected in sequence.

The trapezoidal waveguide 1, trapezoidal waveguide 2, trapezoidal waveguide 3, S-shaped curved waveguide 1, S-shaped curved waveguide 2, straight waveguide 1, straight waveguide 2, S-shaped curved waveguide 3, S-shaped curved waveguide 4, trapezoidal waveguide 4, Both the trapezoidal waveguide 5 and the trapezoidal waveguide 6 are single-mode waveguides;

The S-bend waveguide 1, S-bend waveguide 2, straight waveguide 2, S-bend waveguide 3 and S-bend waveguide 4 have the same width;

The S-bend waveguide 1 and the S-bend waveguide 2 have different lengths;

The lengths of the S-bend waveguide 3 and the S-bend waveguide 4 are different;

The straight waveguide 1 and the straight waveguide 2 have the same length but different widths;

The trapezoidal waveguide 1, the multimode waveguide 1, the trapezoidal waveguide 2 and the trapezoidal waveguide 3 constitute an optical branching structure;

The trapezoidal waveguide 4, the trapezoidal waveguide 5, the multimode waveguide 2 and the trapezoidal waveguide 6 form an optical combination structure;

The trapezoidal waveguide 2, S-shaped curved waveguide 1, straight waveguide 1, S-shaped curved waveguide 3 and trapezoidal waveguide 4 form an upper branch; the trapezoidal waveguide 3, S-shaped curved waveguide 2, straight waveguide 2, and S-shaped curved waveguide 4 and the trapezoidal waveguide 5 constitute the lower branch. The light waves propagate in the upper branch and the lower branch to produce a phase difference The phase difference has a nonlinear relationship with the wavelength of the light wave, Expressed as

in is the phase difference between the straight waveguides in the upper branch and the lower branch, is the phase difference of the S-shaped curved waveguide in the upper branch and the lower branch

where L _arm is the length of straight waveguide 1 and straight waveguide 2, n _eff1 (λ) is the effective refractive index of straight waveguide 1 (7), n _eff2 (λ) is the length of straight waveguide 2 (8), S-type waveguide 1, S ΔL _s is the total length of S-type waveguide 1 and S-type waveguide 3 in the upper branch and the total length of S-type waveguide 2 and S-type waveguide in the lower branch The difference in total length of 4.

The light waves in the upper branch and the lower branch enter the multimode waveguide 2 through the trapezoidal waveguide 4 and the trapezoidal waveguide 5 respectively, and output through the trapezoidal waveguide 6 after being combined. The light waves of the upper branch and the lower branch interfere during the combining process, and the power of the interference light wave output through the trapezoidal waveguide 6 is expressed as

Wherein P _in is the light wave power entering the trapezoidal waveguide 1 .

Example.

Fig. 2 is an integrated waveguide optical biochemical sensor system based on spectrum splitting according to an embodiment of the present invention. The wide-spectrum light source emits a light wave with a certain spectral width through the trapezoidal waveguide 1 and enters the multimode waveguide 1, and is divided into two routes, the trapezoidal waveguide 2 and the trapezoidal waveguide 3, respectively output. Figure 3 shows the trapezoidal waveguide 1, multimode waveguide 1, trapezoidal waveguide 2 and trapezoidal waveguide 3 Construct the optical branch structure diagram, wherein: W ₂ =1 μm, L _{taper_M} =62 μm, W _taper =2.2 μm, D=4.6 μm, W _M =9 μm, L _M =74 μm. Fig. 4 is a simulation result of light waves propagating in the optical branching structure. Light waves propagate from the trapezoidal waveguide 2 and the trapezoidal waveguide 3 into the upper branch and the lower branch respectively.

The solution to be tested flows through the upper branch and the lower branch through the microfluidic channel. Fig. 5 is a cross-sectional structure diagram of the straight waveguide 1 and the straight waveguide 2 in the sensor. The core width W 1 of the straight waveguide ₁ = 1.4 μm, the core width W ₂ of the straight waveguide 2 = 1 μm, and the core height H of the straight waveguide 1 and the straight waveguide 2 = 1.2 μm. The light wave propagates in the upper branch and the lower branch, and the evanescent wave interacts with the solution to be measured in the upper cladding of the waveguide. Fig. 6 shows that under the condition that the solutions to be tested with different refractive indices n _c flow through the upper branch and the lower branch, the light wave propagates in the upper branch and the lower branch to generate a phase difference. It can be seen from Figure 6 that the phase difference It has a non-linear relationship with the wavelength of light. Fig. 7 is a spectrum diagram obtained by measuring the light waves in the upper branch and the lower branch after passing through the optical combined circuit structure formed by the trapezoidal waveguide 4, the trapezoidal waveguide 5 and the multimode waveguide 2 and then outputting to the spectrum analyzer. It can be seen that due to the phase difference The nonlinear relationship with the wavelength of the light wave, when the refractive index of the solution to be measured changes, the output spectrum splits sharply, and the wavelength of the interference minimum value is separated. Figure 8 shows the corresponding relationship curve between the amount of change in the refractive index of the solution to be measured and the amount of wavelength separation of the interference extremum. According to FIG. 8 , the change amount Δn _c of the upper cladding refractive index is obtained by detecting the change amount of the interference extreme wavelength, and then the concentration of the solution to be measured is obtained.

The above descriptions are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Anyone familiar with the technical field within the technical scope described in the present invention, according to the technical scheme of the present invention and its inventive concepts to make equivalent replacements or changes, shall be covered by the protection scope of the present invention.

Claims (8)

1. An integrated waveguide optical biochemical sensor based on spectrum splitting, characterized in that, The integrated waveguide optical biochemical sensor includes trapezoidal waveguide 1 (1), multimode waveguide 1 (2), trapezoidal waveguide 2 (3), trapezoidal waveguide 3 (4), S-bend waveguide 1 (5), S-bend waveguide 2 (6), straight waveguide 1 (7), straight waveguide 2 (8), S-shaped curved waveguide 3 (9), S-shaped curved waveguide 4 (10), trapezoidal waveguide 4 (11), trapezoidal waveguide 5 (12), Multimode waveguide 2 (13) and trapezoidal waveguide 6 (14), trapezoidal waveguide 1 (1) and multimode waveguide 1 (2), trapezoidal waveguide 2 (3), S-bend waveguide 1 (5), straight waveguide 1 (7), S-shaped curved waveguide 3 (9) and trapezoidal waveguide 4 (11) are connected in sequence, trapezoidal waveguide 3 (4), S-shaped curved waveguide 2 (6), straight waveguide 2 (8), S-shaped curved waveguide 4 (10) is connected with trapezoidal waveguide 5 (12) in sequence, trapezoidal waveguide 2 (3) and trapezoidal waveguide 3 (4) are respectively connected with multimode waveguide 1 (2), trapezoidal waveguide 4 (11) and trapezoidal waveguide 5 (12) They are respectively connected to the multimode waveguide 2 (13), the multimode waveguide 2 (13) and the trapezoidal waveguide 6 (14). The above-mentioned waveguides are all rectangular waveguides, and the overall connection is a ring. 2. integrated waveguide optical biochemical sensor according to claim 1, is characterized in that, described trapezoidal waveguide 1 (1), trapezoidal waveguide 2 (3), trapezoidal waveguide 3 (4), S-type curved waveguide 1 (5) ), S-shaped curved waveguide 2 (6), straight waveguide 1 (7), straight waveguide 2 (8), S-shaped curved waveguide 3 (9), S-shaped curved waveguide 4 (10), trapezoidal waveguide 4 (11), Both the trapezoidal waveguide 5 (12) and the trapezoidal waveguide 6 (14) are single-mode waveguides. 3. The integrated waveguide optical biochemical sensor according to claim 1 or 2, characterized in that, The widths of the S-shaped curved waveguide 1 (5), S-shaped curved waveguide 2 (6), straight waveguide 2 (8), S-shaped curved waveguide 3 (9) and S-shaped curved waveguide 4 (10) are the same; The lengths of the S-bend waveguide 1 (5) and the S-bend waveguide 2 (6) are different; The lengths of the S-bend waveguide 3 (9) and the S-bend waveguide 4 (10) are different; The straight waveguide 1 ( 7 ) and the straight waveguide 2 ( 8 ) have the same length and different widths. 4. The integrated waveguide optical biochemical sensor according to claim 1 or 2, characterized in that, The trapezoidal waveguide 1 (1), the multimode waveguide 1 (2), the trapezoidal waveguide 2 (3) and the trapezoidal waveguide 3 (4) constitute an optical branching structure; The trapezoidal waveguide 4 (11), the trapezoidal waveguide 5 (12), the multimode waveguide 2 (13) and the trapezoidal waveguide 6 (14) form an optical combination structure; The trapezoidal waveguide 2 (3), S-shaped curved waveguide 1 (5), straight waveguide 1 (7), S-shaped curved waveguide 3 (9) and trapezoidal waveguide 4 (11) constitute the upper branch; the trapezoidal waveguide 3 ( 4), S-shaped curved waveguide 2 (6), straight waveguide 2 (8), S-shaped curved waveguide 4 (10) and trapezoidal waveguide 5 (12) constitute the lower branch. 5. integrated waveguide optical biochemical sensor according to claim 3, is characterized in that, The trapezoidal waveguide 1 (1), the multimode waveguide 1 (2), the trapezoidal waveguide 2 (3) and the trapezoidal waveguide 3 (4) constitute an optical branching structure; The trapezoidal waveguide 4 (11), the trapezoidal waveguide 5 (12), the multimode waveguide 2 (13) and the trapezoidal waveguide 6 (14) form an optical combination structure; The trapezoidal waveguide 2 (3), S-shaped curved waveguide 1 (5), straight waveguide 1 (7), S-shaped curved waveguide 3 (9) and trapezoidal waveguide 4 (11) constitute the upper branch; the trapezoidal waveguide 3 ( 4), S-shaped curved waveguide 2 (6), straight waveguide 2 (8), S-shaped curved waveguide 4 (10) and trapezoidal waveguide 5 (12) constitute the lower branch. 6. A method of using the integrated waveguide optical biochemical sensor based on spectrum splitting described in claim 1, 2 or 5, characterized in that, sensing detection is carried out according to the following steps: The light wave with a certain spectral width enters the multimode waveguide 1 (2) through the trapezoidal waveguide 1 (1), and is divided into two paths, respectively output by the trapezoidal waveguide 2 (3) and the trapezoidal waveguide 3 (4), and enters the upper branch and the lower branch ; The light wave propagates in the upper branch and the lower branch, and the evanescent wave interacts with the solution to be measured in the upper cladding of the waveguide; Because the waveguide structures of the upper branch and the lower branch are different, including the length of the S-bend waveguide 1 (5) and the S-bend waveguide 2 (6), the width of the straight waveguide 1 (7) and the straight waveguide 2 (8) Different, the length of the S-shaped curved waveguide 3 (9) and the S-shaped curved waveguide 4 (10) is different, and the light wave propagates in the upper branch and the lower branch to produce a phase difference Expressed as in is the phase difference between the straight waveguides in the upper branch and the lower branch, is the phase difference of the S-shaped curved waveguide in the upper branch and the lower branch where L _arm is the length of straight waveguide 1 (7) and straight waveguide 2 (8), n _eff1 (λ) is the effective refractive index of straight waveguide 1 (7), n _eff2 (λ) is straight waveguide 2 (8), The effective refractive index of S-bend waveguide 1 (5), S-bend waveguide 2 (6), S-bend waveguide 3 (9) and S-bend waveguide 4 (10), ΔL _s is the S-bend in the upper branch The difference between the total length of waveguide 1 (5) and S-bend waveguide 3 (9) and the total length of S-bend waveguide 2 (6) and S-bend waveguide 4 (10) in the lower branch; The light waves in the upper branch and the lower branch enter the multimode waveguide 2 (13) through the trapezoidal waveguide 4 (11) and the trapezoidal waveguide 5 (12) respectively, and output through the trapezoidal waveguide 6 (14) after the combination; The light waves of the lower branch interfere during the combining process, and the power of the interference light waves output through the trapezoidal waveguide 6 (14) is expressed as Wherein P _in is the light wave power entering the trapezoidal waveguide 1 (1); When the refractive index of the upper cladding changes, that is, when the concentration of the solution to be measured changes, the effective refractive indices n _eff1 (λ) and n _eff2 (λ) of the waveguide change, causing light waves to propagate in the upper branch and the lower branch resulting phase difference changes happened. 7. a kind of method with the integrated waveguide optical biochemical sensor based on spectrum splitting according to claim 3, is characterized in that, carries out sensing detection according to the following steps: The light wave with a certain spectral width enters the multimode waveguide 1 (2) through the trapezoidal waveguide 1 (1), and is divided into two paths, respectively output by the trapezoidal waveguide 2 (3) and the trapezoidal waveguide 3 (4), and enters the upper branch and the lower branch ; The light wave propagates in the upper branch and the lower branch, and the evanescent wave interacts with the solution to be measured in the upper cladding of the waveguide; Because the waveguide structures of the upper branch and the lower branch are different, including the length of the S-bend waveguide 1 (5) and the S-bend waveguide 2 (6), the width of the straight waveguide 1 (7) and the straight waveguide 2 (8) Different, the length of the S-shaped curved waveguide 3 (9) and the S-shaped curved waveguide 4 (10) is different, and the light wave propagates in the upper branch and the lower branch to produce a phase difference Expressed as in is the phase difference between the straight waveguides in the upper branch and the lower branch, is the phase difference of the S-shaped curved waveguide in the upper branch and the lower branch where L _arm is the length of straight waveguide 1 (7) and straight waveguide 2 (8), n _eff1 (λ) is the effective refractive index of straight waveguide 1 (7), n _eff2 (λ) is straight waveguide 2 (8), The effective refractive index of S-bend waveguide 1 (5), S-bend waveguide 2 (6), S-bend waveguide 3 (9) and S-bend waveguide 4 (10), ΔL _s is the S-bend in the upper branch The difference between the total length of waveguide 1 (5) and S-bend waveguide 3 (9) and the total length of S-bend waveguide 2 (6) and S-bend waveguide 4 (10) in the lower branch; The light waves in the upper branch and the lower branch enter the multimode waveguide 2 (13) through the trapezoidal waveguide 4 (11) and the trapezoidal waveguide 5 (12) respectively, and output through the trapezoidal waveguide 6 (14) after the combination; The light waves of the lower branch interfere during the combining process, and the power of the interference light waves output through the trapezoidal waveguide 6 (14) is expressed as Wherein P _in is the light wave power entering the trapezoidal waveguide 1 (1); When the refractive index of the upper cladding changes, that is, when the concentration of the solution to be measured changes, the effective refractive indices n _eff1 (λ) and n _eff2 (λ) of the waveguide change, causing light waves to propagate in the upper branch and the lower branch resulting phase difference changes happened. 8. a method with the integrated waveguide optical biochemical sensor based on spectral splitting according to claim 4, is characterized in that, according to the following steps, carry out sensing detection: The light wave with a certain spectral width enters the multimode waveguide 1 (2) through the trapezoidal waveguide 1 (1), and is divided into two paths, respectively output by the trapezoidal waveguide 2 (3) and the trapezoidal waveguide 3 (4), and enters the upper branch and the lower branch ; The light wave propagates in the upper branch and the lower branch, and the evanescent wave interacts with the solution to be measured in the upper cladding of the waveguide; Because the waveguide structures of the upper branch and the lower branch are different, including the length of the S-bend waveguide 1 (5) and the S-bend waveguide 2 (6), the width of the straight waveguide 1 (7) and the straight waveguide 2 (8) Different, the length of the S-shaped curved waveguide 3 (9) and the S-shaped curved waveguide 4 (10) is different, and the light wave propagates in the upper branch and the lower branch to produce a phase difference Expressed as in is the phase difference between the straight waveguides in the upper branch and the lower branch, is the phase difference of the S-shaped curved waveguide in the upper branch and the lower branch where L _arm is the length of straight waveguide 1 (7) and straight waveguide 2 (8), n _eff1 (λ) is the effective refractive index of straight waveguide 1 (7), n _eff2 (λ) is straight waveguide 2 (8), The effective refractive index of S-bend waveguide 1 (5), S-bend waveguide 2 (6), S-bend waveguide 3 (9) and S-bend waveguide 4 (10), ΔL _s is the S-bend in the upper branch The difference between the total length of waveguide 1 (5) and S-bend waveguide 3 (9) and the total length of S-bend waveguide 2 (6) and S-bend waveguide 4 (10) in the lower branch; The light waves in the upper branch and the lower branch enter the multimode waveguide 2 (13) through the trapezoidal waveguide 4 (11) and the trapezoidal waveguide 5 (12) respectively, and output through the trapezoidal waveguide 6 (14) after the combination; The light waves of the lower branch interfere during the combining process, and the power of the interference light waves output through the trapezoidal waveguide 6 (14) is expressed as Wherein P _in is the light wave power entering the trapezoidal waveguide 1 (1); When the refractive index of the upper cladding changes, that is, when the concentration of the solution to be measured changes, the effective refractive indices n _eff1 (λ) and n _eff2 (λ) of the waveguide change, causing light waves to propagate in the upper branch and the lower branch resulting phase difference changes happened.