CN105628621A - Heatless on-chip integrated optical waveguide biosensor chip - Google Patents

Abstract

A heatless on-chip integrated optical waveguide biosensor chip comprises an integrated broadband light source, a sensing area with at least one micro-ring, an array waveguide grate and an integrated detector array, wherein the broadband light source is connected with the input end of the sensing area; the array waveguide grate comprises three input array waveguides and at least three output array waveguides, the middle input waveguide of the three input array waveguides is connected with an output waveguide at the downloading end of the sensing area, the other two of the three input array waveguides are in symmetric distribution with respect to the middle input waveguides, and the at least three output waveguides are connected with the detector array comprising detectors as many as the output waveguides; along with external environment temperature change, wavelength shift of sensing micro-rings in detection substances is as same as that of the array waveguide grate. The heatless on-chip integrated optical waveguide biosensor chip has the advantages that detection cost of micro-ring-based optical waveguide sensors is reduced, and the temperature-dependent problem of micro-ring sensors is solved effectively.

Description

A kind of optical waveguide biosensor sensor chip integrated on sheet without heat

Technical field

The present invention relates to optical waveguide biosensor sensor, optical waveguide biosensor sensor chip integrated on especially a kind of sheet without heat.

Background technology

At present, obtain based on the optical waveguide biosensor sensor of micro-loop and study widely. Owing to the resonance peak of ring has very big Q-value (Q=��_res/����_3dB,��_resIt is the resonance wavelength of ring, �� ��_3dBIt is half maximum overall with, i.e. three dB bandwidth of ring response spectrum) so that the three dB bandwidth value �� �� of ring_3dBVery little, so wanting center response wave length during accurately detecting ring resonance to be accomplished by using high-precision tunable laser or high-precision spectrogrph, this considerably increases testing cost. M.Iqbal et al. (M.Iqbal, etal, Label-freebiosensorarraysbasedonsiliconringresonatorsand high-speedopticalscanninginstrumentation, IEEEJSTQE, vol.16, no.3, pp.654-661,2010.) utilize micro-loop as sensing unit and combine complexity high accuracy surface sweeping system achieve 10^-7The refractive index detectivity of magnitude and the real-time detection of various biomolecules, whole system is owing to employing discrete component, and structure is complex, and cost is much more expensive. D.-X.Xu et al. (D.-X.Xu, etal, Real-timecancellationoftemperatureinducedresonanceshifts inSOIwirewaveguideringresonatorlabel-freebiosensorarrays, Opt.Express, vol.18, no.22, pp.22867-22879, 2010.) propose and reference rings is inserted in microchannel so that reference rings has truly identical external environment to carry out the structural representation of biological detection with sensing ring together with sensing ring, then the variations in temperature relation between reference rings and sensing ring is being utilized to be undertaken eliminating by the temperature effects in sensing ring thus improving the true and reliable property of final test data further, but this structure employs the high accuracy tunable laser that resolution is 1pm, increase testing cost. what research group for army building of Zhejiang University proposes the sensing detection signal (LeiJin of dicyclo cascade, etal, Opticalwaveguidedouble-ringsensorusingintensityinterroga tionwithlow-costbroadbandsource, OpticsLetters, vol.36, no.7, pp.1128 1130, 2011.), it utilizes faint Free Spectral Range (FSR) difference between sensing ring and reference rings that transducing signal is carried out vernier amplification, substantially increase sensing detection sensitivity, utilize wide spectrum light source to greatly reduce testing cost as detection light source at the input of sensor simultaneously, although this structure has simply, highly sensitive and low cost and other advantages, but the residing therebetween external environment difference (such as the temperature dependency etc. of the two) of sensing ring and reference rings is bigger, so the temperature noise signal in this structure is also amplified by vernier simultaneously, us are made to be difficult to distinguish noise components from final detection signal, the accuracy of experimental result is caused certain impact, the shake of light source power simultaneously also can affect the accuracy of testing result.

The existing optical waveguide sensor based on micro-loop is required for being equipped with high-precision tunable laser, the high accuracy scanning-detecting system of spectrogrph or complexity, this micro-ring sensor also has temperature correlation problem simultaneously, need to be aided with the transducing signal change that relevant variations in temperature reference structure causes to eliminate temperature, on the other hand, biologic sensor chip integrated on sheet is due to its miniaturization, low cost, function admirable, can be integrated with Circuits System and finally realize the module of a functionalization, this module can be widely applied to portable medical, in electronic mobile device etc., thus the research of bio-sensing chip integrated on sheet gets most of the attention.

Summary of the invention

Deficiency for the temperature correlation problem that the testing cost height and micro-ring sensor that overcome the existing optical waveguide sensor based on micro-loop face, the invention provides optical waveguide biosensor sensor chip integrated on a kind of sheet without heat, reduce the testing cost of the optical waveguide sensor based on micro-loop and effectively solve the temperature correlation problem that micro-ring sensor faces, and realizing chip sensing and detecting system integrated on a sheet.

It is an object of the invention to be achieved through the following technical solutions:

A kind of optical waveguide biosensor sensor chip integrated on sheet without heat, including an integrated wideband light source, the sensitive zones of at least one micro-loop, one array waveguide grating, one integrated detector array, described wideband light source is connected with the input of micro-loop sensitive zones, described array waveguide grating includes three input array waveguides and at least three output array waveguides, one, centre input waveguide in three described input waveguides is connected with the downloading end output waveguide of micro-loop sensitive zones, all the other two input waveguides are symmetric about intermediate input waveguide, at least three described output waveguides have equal number of detector array with one and are connected, the wavelength shift that sensing micro-loop changes with ambient temperature in detection material is identical with the wavelength shift that array waveguide grating changes with ambient temperature, and namely sensing micro-loop and array waveguide grating have identical temperature dependency with ambient temperature change.

Further, described array waveguide grating has three input waveguides, is respectively labeled as I_-1��I₀And I₁, I₀Centered by input waveguide and being connected with the downloading end output waveguide of micro-loop sensitive zones, I_-1And I₁About I₀Symmetry, input waveguide I₀And between the first of array waveguide grating planar waveguide, inserting one section of linear taper broadening region, the terminal end width in this broadening region depends primarily on I₀When the input light field of end again focuses on the focal line of second planar waveguide of array waveguide grating, this Light Energy can be received by how many adjacent output channels, is simultaneously entered waveguide I_-1And I₁With the throat width and output array waveguide of the junction of first planar waveguide of array waveguide grating identical with the throat width of the junction of second planar waveguide.

Further, when described micro-loop sensitive zones contains multiple micro-loop, there is between each micro-loop identical waveguiding structure parameter and different ring girths.

Beneficial effects of the present invention is mainly manifested in: 1, realizing the sensing detection without heat, this chip, without extra temperature control device and temperature reference device, reduces power consumption and the cost of chip; 2, it is using integrated wideband light source as detecting light source, array waveguide grating is utilized to speculate the resonance wavelength of sensing micro-loop, utilize integrated detector array to the watt level obtaining in each output channel of array waveguide grating and then to analyze the information change occurred in sensing micro-loop simultaneously, the detection of whole chip, without expensive high accuracy tunable laser or spectrogrph, greatly reduces cost; 3, it can realize in different material platforms, such as silicon nitride (Si₃N₄) and the platform such as silicon (Si).

Accompanying drawing explanation

Fig. 1 is the detailed description of the invention structural representation of optical waveguide biosensor sensor chip integrated on a kind of sheet without heat that the present invention proposes, wherein sensitive zones only one of which micro-loop.

Fig. 2 is the detailed description of the invention structural representation of optical waveguide biosensor sensor chip integrated on a kind of sheet without heat that the present invention proposes, and wherein sensitive zones contains multiple micro-loop.

Fig. 3 is the structural representation of array waveguide grating (AWG).

Fig. 4 is the sensing micro-loop waveguide cross-section schematic diagram when solution to be detected or analyte make top covering.

Fig. 5 is the cross sectional representation of Waveguide array in array waveguide grating.

The center input waveguide that Fig. 6 is array waveguide grating is coupled into the schematic diagram in the adjacent many output waveguides of array waveguide grating when this waveguide focuses on output planar waveguide focal line again with the field distribution on input planar waveguide interface.

Fig. 7 is that the output spectrum to array waveguide grating utilizes centroid algorithm to calculate the schematic diagram of sensing micro-ring resonant wavelength.

Fig. 8 is silicon core layer thickness is the SOI slab waveguide schematic diagram that the temperature dependency in different top covering situations changes with duct width respectively of 250nm.

When Fig. 9 is room temperature 25 DEG C, the watt level distribution that when sensitive zones covering is pure water (refractive index is 1.325) solution, each output channel of AWG detects.

When Figure 10 is 50 DEG C, the watt level distribution that when sensitive zones covering is pure water (refractive index is 1.32224) solution, each output channel of AWG detects.

When Figure 11 is 25 DEG C, the watt level distribution that when sensitive zones covering is (refractive index is 1.335) solution of analyte-containing, each output channel of AWG detects.

When Figure 12 is 50 DEG C, the watt level distribution that when sensitive zones covering is (refractive index is 1.33224) solution of analyte-containing, each output channel of AWG detects.

When Figure 13 is ambient temperature respectively 0 DEG C, 25 DEG C, 50 DEG C and 80 DEG C, sensitive zones is in the aqueous solution of different refractivity, the wavelength shift that obtains of straight-through outfan utilizing sensing micro-loop and the wavelength shift utilizing the spectral detection of array waveguide grating to arrive by centroid algorithm are (wherein, lines represent calculated resonance wavelength drift size in the straight-through end of ring, and discrete point represents the resonance wavelength drift size of the micro-loop detected in AWG).

Detailed description of the invention

Below in conjunction with accompanying drawing, the invention will be further described.

With reference to Fig. 1��Figure 13, a kind of optical waveguide biosensor sensor chip integrated on sheet without heat, including an integrated wideband light source 1, the sensitive zones 2 of at least one micro-loop, one array waveguide grating (AWG) 11, one detector array 20, described wideband light source 1 is connected with the input of micro-loop sensitive zones 2, described array waveguide grating 11 includes three input array waveguides and at least three output array waveguides, one, centre input waveguide in three described input waveguides is connected with the downloading end output waveguide of micro-loop sensitive zones 2, all the other two input waveguides are symmetric about intermediate input waveguide, at least three described output waveguides have equal number of detector array 20 and are connected with one, the wavelength shift that sensing micro-loop changes with ambient temperature in detection material is identical with the wavelength shift that array waveguide grating 11 changes with ambient temperature, and namely the two has identical temperature dependency.

Wideband light source 1 send optically coupling in the sensing micro-loop 4 of sensitive zones 2, after resonance, exported the center input I of array waveguide grating by the downloading end 5 of sensing micro-loop 4₀6, and transmission in array waveguide grating 11 is entered through the linear taper broadening region 7 that is connected with 6, finally it is coupled in connected detector array 20 by the output array waveguide 12 of array waveguide grating.

Array waveguide grating 11 has three input 8 (I_-1)��9(I₁)��6(I₀) and 8 and 9 symmetrical about 6, the center input I of array waveguide grating₀6 places being connected with array waveguide grating 11 insert one section of linear taper broadening region 7, and the end broadening width 16 of 7 depends primarily on this Light Energy when the input optical field distribution 21 of 6 again focuses on the focal line 13 of second planar waveguide 19 of array waveguide grating and can be received by how many adjacent output channels, Fig. 4 gives the schematic diagram that this input light field 21 is received by adjacent four output waveguides when exporting and focusing on focal line 13, when being received by an output waveguide for 21, the terminal end width 16 of 7 is identical with the throat width 14 of output array waveguide 12; When 16 are exceeded an output waveguide reception, the terminal end width 16 of 7 is more than the throat width 14 of output array waveguide 12. Meanwhile, 8 is identical with the throat width 14 of output array waveguide 12 with the terminal end width 17 of 9.

Each output array waveguide 12 of array waveguide grating 11 is corresponding to I₀The determination of each channel center response wave length during end 6 input is by referring mainly to input I_-18 and I₁9 determine, the center response wave length �� _ i_I of #i output channel time namely corresponding to 6 input₀Should be center response wave length �� _ i_I that this passage obtains when 8 and 9 input respectively respectively_-1With �� _ i_I₁Meansigma methods, i.e. �� _ i_I₀=(�� _ i_I_-1+��_i_I₁)/2, thus measure from 8 and 9 respectively input time 12 corresponding output response wave length just can extrapolate 6 input time 12 in the center response wave length �� _ i_I of each passage₀, the reference input 8 and 9 that is optically coupled into of external light source is that the grating coupler 10 by chip surface realizes.

The output wavelength drift value that the micro-loop 4 of sensitive zones varies with temperature is identical with the output wavelength drift value that array waveguide grating 11 varies with temperature, and namely the two has identical temperature dependency. the wavelength shift varied with temperature due to both micro-loop and array waveguide grating depends primarily on the thermo-optical coeffecient of waveguide dimensions, operation wavelength and waveguide top covering material, the waveguide cross-section schematic diagram that Fig. 5,6 Waveguide arrays 15 that sets forth sensing micro-loop 4 and array waveguide grating 11 use. when designing described chip, when first considering the top covering material doing sensing micro-loop 4 containing the analyte of material to be tested, the wave length shift coefficient that sensing micro-loop 4 varies with temperature under a certain specific wavelength and different waveguide structure, then the wave length shift coefficient that array waveguide grating 11 varies with temperature is considered further that, the selection of the top covering material of array waveguide grating 11 is mainly from stability, easy windowing and thermo-optical coeffecient consider, calculate array waveguide grating 11 wave length shift coefficient with different Waveguide array 15 change in size under particular job wavelength and selected top covering material simultaneously, finally compare the temperature correlation coefficient of sensing ring 4 and array waveguide grating 11, determine respective waveguide dimensions corresponding when the two is identical, it should be noted that sensing micro-loop 4 waveguide dimensions choose to take into account simultaneously the highly sensitive of sensing detection and waveguide loss little.

The resonance wavelength information of sensing micro-loop 4 calculates mainly through array waveguide grating 11, utilizes a kind of centroid algorithm to realize, the center response wave length �� of sensing micro-loop 4_ringEnter transmission in 11 through 6, be then outputted to 12, then be coupled in detector array 20, and the luminous power that the #i detector in 20 receives is Power_i (��_ring), the center response wave length �� _ i_I according to this passage being previously obtained simultaneously₀, we just can extrapolate the sensing micro-loop 4 resonance central wavelength lambda in t to utilize centroid algorithm^t _{ring_AWG}, it may be assumed that

${\mathrm{\λ}}_{ring\_AWG}^t=\frac{\underset{i}{\mathrm{\Σ}}Power\_i\left({\mathrm{\λ}}_{ring}\right)\×\mathrm{\λ}\_i\_I_0}{\underset{i}{\mathrm{\Σ}}Power\_i\left({\mathrm{\λ}}_{ring}\right)}$ (equation 1)

By this wavelength X^t _{ring_AWG}Initial communication wavelength X with sensing micro-loop 4⁰ _{ring_AWG}Relatively just can extrapolate the wavelength shift �� �� after there is material detection in 4. Fig. 7 gives the resonance wavelength schematic diagram that centroid algorithm calculates sensing micro-loop 4.

When sensitive zones 2 contains the resonance micro-loop 4 of the individual different girths of N (N >=2), the output array waveguide 12 of array waveguide grating 11 is divided into independent N group, the detection of an each group of corresponding sensing micro-loop, and be utilized respectively centroid algorithm and extrapolate the resonance wavelength information of sensing micro-loop each group corresponding.

Below we by the example actual with come the present invention is further elaborated:

Consider the SOI material that silicon layer thickness is 250nm, select SU-8 polymer and earth silicon material as the top covering of whole chip, the detection material of consideration sensitive zones is the aqueous solution of different refractivity simultaneously, and this situation is the inspection type of most of biosensor. Following table gives the physical parameter of involved material:

Fig. 8 gives the sensing micro-loop based on slab waveguide and makes top covering (waveguiding structure is as shown in Figure 5 a) and array waveguide grating (waveguiding structure is as shown in Figure 6 a) respectively at SiO at aqueous solution₂When making top covering with SU-8, the mode of operation of waveguide is TM basic mode, the relation schematic diagram that the spectrum of sensing micro-loop and AWG varies with temperature, and we can see that sensing micro-loop is relevant with duct width and top covering material with the temperature dependency of AWG from this figure. consider the duct width in sensing micro-loop and should meet the superperformance (namely duct width can not be too narrow) of single mode transport and low-loss requirement and AWG, simultaneously take account of micro-loop and open the simple operability of sensing window, we select SU-8 as the top covering of whole chip, and this material has good stability and life-span, widely use in CMOS industry. in order to reach chip without thermal characteristics, sensing micro-loop and AWG should have identical temperature dependency, according to Fig. 8, when sensing micro-loop width near 400nm and array waveguide grating when SU-8 makes top covering width near 1000nm both there is identical temperature dependency, and sensing micro-loop during 400nm and have good sensitivity and less waveguide loss, the duct width of 1000nm also makes the array waveguide grating (shown in Fig. 3) of saddle-shaped configuration have good performance simultaneously. it can also be seen that from this figure, for the waveguide of array waveguide grating when SU-8 makes top covering and width more than 1000nm, it tends to constant with the temperature dependency of duct width change, when namely changing duct width, the wavelength shift that array waveguide grating varies with temperature is constant, that is under 1000nm width, Waveguide array and planar waveguide (can regard that duct width is far longer than the slab waveguide of 1000nm as) in array waveguide grating have close wavelength shift, reduce the detection error that the temperature dependency of planar waveguide causes, under this width, Waveguide array has bigger making tolerance simultaneously.

After determining the waveguide dimensions of sensing micro-loop 4 and array waveguide grating 11, we are accomplished by determining that array waveguide grating 11 is at center input I₀Center response wave length �� _ i_I that during 6 input, each output channel is corresponding₀In the design, our array of designs waveguide optical grating has 16 output channels and channel pitch is 0.8nm, the Free Spectral Range of simultaneously designed sensing micro-loop 4 should be greater than the channel pitch of the array waveguide grating 11 of design and the product (0.8 �� 16=12.8nm) of channel number, the output channel ordinal number of array waveguide grating 11 is 1��16, the center response wave length that each passage is corresponding is 1544.4nm��1556.4nm, step-length is 0.8nm, but in the chip of actual fabrication, it would be desirable to utilize about 6 (input I₀) symmetrical 8 (input I_-1) and 9 (input I₁) extrapolate the center response wave length �� _ i_I of each output channel corresponding during 6 input₀. After designing the center output wavelength that each output channel is corresponding, we need the terminal end width 16 in the broadening region 7 of design 6, assume that the throat width 14 that the output array waveguide 12 of the array waveguide grating of design is connected with 19 is 0.8 ��m, adjacent output channel center distance is 1.5 ��m, for making the input field 21 during 6 input can be received by 10/3 adjacent output channel, the terminal end width 16 of 7 is selected to be 1.5 �� 10/3=5 ��m.

Next, it is contemplated that sensing micro-loop 4 in solution refractive index from 1.325 change to 1.345 and step-length be 0.005, ambient temperature respectively 0 DEG C simultaneously, room temperature 25 DEG C, 50 DEG C, when 80 DEG C, the wavelength shift that calculates of straight-through outfan 3 of sensing micro-loop 4 and the wavelength shift utilizing centroid algorithm to extrapolate the performance number detected in detector array 20. when Fig. 9 gives room temperature 25 DEG C, when the refractive index of aqueous solution is 1.325, the light that center resonance wavelength is 1550nm of sensing micro-loop enters, through the center input 6 of Waveguide array, the power distribution schematic diagram obtained in each output channel 12 of array waveguide grating after transmission in array waveguide grating 11, can be seen that the distribution in output channel of the whole power is symmetrical about passage 8, and the power of passage 8 is maximum, and the designed central wavelength of passage 8 is 1550nm in AWG, Figure 10 gives ambient temperature when being 50 DEG C, each channel output power scattergram that the sensing micro-loop detected in each output channel 12 of array waveguide grating obtains after the resonance center wavelength variation that variation of ambient temperature causes, find out that the distribution of this power is still symmetric about passage 8 (center response wave length is 1550nm) from this figure, and power is maximum in passage 8, thus demonstrate the characteristic without transconversion into heat of designed chip, namely the power distribution detected in each output channel of array waveguide grating does not change with the change of ambient temperature. when Figure 11 gives 25 DEG C, the power distribution schematic diagram that sensitive zones covering is refractive index to be detected in each output channel of array waveguide grating when being the aqueous solution of 1.335, find out that the change sensing micro-ring resonant centre wavelength caused due to the change of sensitive zones cladding index causes the power changes in distribution detected each output channel of array waveguide grating from this figure, maximum power value compared to Fig. 9, Figure 11 occurs in passage 10 and power distribution does not have symmetry. when Figure 12 gives 50 DEG C, in this aqueous solution, the power distribution schematic diagram detected in each output channel of array waveguide grating, it can be seen that Figure 11 and Figure 12 has identical power distribution, demonstrates the temperature-insensitive characteristic of designed chip again. according to the power distribution size detected in each channel center response wave length 1544.4nm��1556.4nm (interval 0.8nm) demarcated in array waveguide grating and each passage, we obtain ambient temperature respectively 0 DEG C, 25 DEG C, when 50 DEG C and 80 DEG C, the wavelength shift detected in the wavelength shift that obtains of straight-through outfan 3 utilizing sensing micro-loop when sensitive zones is in the aqueous solution of different refractivity and the array waveguide grating utilizing centroid algorithm to obtain, as shown in figure 13, wherein, lines represent the wave length shift utilizing the straight-through outfan 3 of sensing micro-loop to calculate, discrete point represents the wave length shift utilizing centroid method to extrapolate according to the testing result in each output channel of array waveguide grating, as can be seen from this figure, the drift of the resonance center response wave length of sensing micro-loop is relevant with the refractive index of ambient temperature and aqueous solution, but no matter how ambient temperature changes, as long as it is constant to detect solution in sensing micro-loop, so the power in each output channel of array waveguide grating being distributed utilizes the wavelength shift that centroid method is extrapolated just constant all the time, and the change along with sensing micro-loop top covering solution concentration, the wave length shift size distribution extrapolated in array waveguide grating is passed through when room temperature 25 DEG C to sense on the calculated wave length shift line of straight-through outfan 3 of micro-loop, this absolutely proves that the biologic sensor chip that we design is temperature-insensitive, and the drift of wavelength is only relevant with the variations in refractive index of sensing micro-loop top covering solution (i.e. analyte), and the wavelength shift (under room temperature) that directly the straight-through outfan of detection micro-loop obtains is identical with the wavelength shift utilizing centroid method to extrapolate array waveguide grating, this further illustrates the reliability of designed chip inspection result.

In addition, Fig. 2 gives the biologic sensor chip schematic diagram of block form sensing detection, it is except the sensing micro-loop that the individual different girths of N (N >=2) are contained in sensing detection region, other design parameters all with above design identical, detect about each micro-Ring current distribution response wave length, only the output array waveguide 12 of array waveguide grating need to be divided into the individual independent part of N (N >=2), each detection corresponding partly to a sensing micro-loop, it does not interfere with each other, then each independent sector is utilizing foregoing center of gravity method detect.

Claims (3)

1. optical waveguide biosensor sensor chip integrated on the sheet without heat, it is characterized in that: include an integrated wideband light source, the sensitive zones of at least one micro-loop, one array waveguide grating, one integrated detector array, described wideband light source is connected with the input of micro-loop sensitive zones, described array waveguide grating includes three input array waveguides and at least three output array waveguides, one, centre input waveguide in three described input waveguides is connected with the downloading end output waveguide of micro-loop sensitive zones, all the other two input waveguides are symmetric about intermediate input waveguide, at least three described output waveguides have equal number of detector array with one and are connected, the wavelength shift that sensing micro-loop changes with ambient temperature in detection material is identical with the wavelength shift that array waveguide grating changes with ambient temperature, and namely sensing micro-loop and array waveguide grating have identical temperature dependency.

2. optical waveguide biosensor sensor chip integrated on the sheet without heat as claimed in claim 1, it is characterised in that: described array waveguide grating has three input waveguides, is respectively labeled as I_-1��I₀And I₁, I₀Centered by input waveguide and being connected with the downloading end output waveguide of micro-loop sensitive zones, I_-1And I₁About I₀Symmetry, input waveguide I₀And between the first of array waveguide grating planar waveguide, insert one section of linear taper broadening region, it is simultaneously entered waveguide I_-1And I₁With the throat width and output array waveguide of the junction of first planar waveguide of array waveguide grating identical with the throat width of the junction of second planar waveguide.

3. optical waveguide biosensor sensor chip integrated on the sheet without heat as claimed in claim 1 or 2, it is characterised in that: when described micro-loop sensitive zones contains multiple micro-loop, there is between each micro-loop identical waveguiding structure parameter and different ring girths.