WO2019019241A1

WO2019019241A1 - Integrated biochemical sensor based on rib optical waveguide

Info

Publication number: WO2019019241A1
Application number: PCT/CN2017/098663
Authority: WO
Inventors: 董瑛; 刘跃明; 王玺; 王晓浩
Original assignee: 清华大学深圳研究生院
Priority date: 2017-07-27
Filing date: 2017-08-23
Publication date: 2019-01-31
Also published as: CN107478607A

Abstract

An integrated biochemical sensor based on a rib optical waveguide comprises an MZI detection chip, an optical fiber support (1), a plurality of polymer cavities, and a micro-channel system which are machined on the same SOI silicon wafer as well as a photoelectric detector and a detection circuit (9) which are provided in the polymer cavities. The MZI detection chip comprises a rib optical waveguide (3), a sample pool (8), a medium tank beam splitter (2), and a medium tank beam combiner (5). An optical fiber is coupled to the rib optical waveguide (3), and the rib optical waveguide (3) is coupled to the photoelectrical detector and the detection circuit (9). Light transmitted by an input end of the rib optical waveguide (3) is split into two branch light beams by the medium tank beam splitter (2); the two branch light beams are transmitted along two waveguide arms respectively; one waveguide arm is coupled to the sample pool (8), and the light beam of the waveguide arm is subjected to phase modulation by a sample in the sample pool (8); the two light beams are combined into an output light beam by the medium tank beam combiner (5); the photoelectric detector and the detection circuit (9) detect a change of light intensity and convert same into an electrical signal, thereby implementing sample detection in the sample pool. The sensor is easy to machine, compact in structure, high in sensitivity, and low in costs.

Description

Integrated biochemical sensor based on ridge optical waveguide

Technical field

The invention relates to the field of optical biochemical sensing technology, in particular to an integrated biochemical sensor based on a ridge optical waveguide.

Background technique

With the rapid development of science and technology, the advanced technology of related disciplines has continuously penetrated into the field of biomedicine, and the development of biomedical testing technology has become increasingly polarized. On the one hand, various types of large-scale automation, high-performance, high-efficiency instruments and equipment have been introduced one after another, greatly improving the efficiency of laboratory analysis and testing; on the other hand, the miniaturization, portability, ease of operation, and timely results of experimental instruments Accuracy, and the new biomedical testing model generated on this basis, namely Point of Care Testing (POCT).

Most integrated biochemical sensors have long interference structures, low coupling efficiency, and are not easy to integrate. In general, in order to reduce the radiation loss, the MZI sensor adopts a small-angle Y-branch structure. In order to obtain an ideal phase modulation result, a large overall size is required. The sub-micron waveguide MZI sensor usually needs to be coupled by grating, and cannot directly With end-face coupling, the coupling efficiency is low; when the waveguide is in contact with the sample, direct immersion is usually adopted, which is not conducive to the integration of the system on chip.

Summary of the invention

The main object of the present invention is to overcome the deficiencies of the prior art and provide an integrated biochemical sensor based on a ridge optical waveguide, which can be directly and efficiently coupled with an optical fiber, is easy to process, has high sensitivity, is resistant to electromagnetic radiation, and has high environmental tolerance. Miniaturization and integration, low cost.

To achieve the above object, the present invention adopts the following technical solutions:

An integrated biochemical sensor based on a ridge optical waveguide, comprising an MZI (Mach-Zehnder interferometer) detecting chip formed on the same SOI silicon wafer, a fiber holder, and a surface bonded to the surface of the MZI detecting chip a plurality of polymer cavities formed by the polymer, a microchannel system formed from a portion of the plurality of polymer cavities, and photodetectors and detections disposed in another portion of the plurality of polymer cavities a circuit, the MZI detection chip comprising a ridge optical waveguide, a sample cell, a dielectric slot beam splitter, and a dielectric slot combiner, the optical fiber being coupled to an end face of the input end of the ridge optical waveguide via the fiber holder, The ridge optical waveguide branches into two waveguide arms on the propagation path to form two light propagation channels, and the output ends of the ridge optical waveguides are coupled Integrating the photodetector and the detection circuit, a waveguide arm of the ridge optical waveguide is coupled to the sample cell, and the microchannel system is coupled to the sample cell for replacing a sample in the sample cell, The light transmitted by the input end of the ridge optical waveguide is decomposed into two branched beams by a dielectric slot beam splitter, one branch beam is used as a reference signal, and the other branch beam is phase-modulated by the sample in the sample cell, and respectively Propagating along the two waveguide arms and merging into an output beam through the media slot combiner, exiting from the output end of the ridge optical waveguide, and detecting and changing the intensity of the emitted light by the photodetector and the detecting circuit An electrical signal is generated to detect the relevant components or concentrations of the sample in the sample cell.

further:

The MZI detecting chip includes a first dielectric groove formed on the SOI silicon wafer, preferably an air groove, and the first dielectric groove cooperates with a T-shaped branch of the ridge optical waveguide to form the medium A slot beam splitter to split a beam of light into two beams by total internal reflection, respectively propagating along the two light propagation channels and performing sample detection.

The ridge optical waveguide has a plurality of 90° bending structures, and the MZI detecting chip includes a plurality of second dielectric grooves, preferably air grooves, formed on the SOI silicon wafer, the second dielectric grooves and The bends of the ridged optical waveguide cooperate to change the direction of propagation of light within the MZI detection chip in a predetermined path by total internal reflection to cause light to propagate according to the predetermined path to complete sample detection.

The one waveguide arm is in direct contact with the sample in the sample cell.

The two light propagation channels are symmetrically disposed on both sides of the waveguide axis of the input and output ends of the ridge optical waveguide.

The polymer is PDMS, preferably forming a cavity therein using an embossed micro-nano process.

The ridge waveguide is a single mode waveguide, and a waveguide portion of the ridge optical waveguide protrudes from a surface of the base material to have a ridge shape.

The fiber holder is on the same axis as the input end of the ridge waveguide, and is formed by deep etching on the surface of the SOI wafer, and has a size equivalent to that of the single mode fiber cladding; preferably, the photodetector is in the ridge waveguide On the axis of the output.

The microchannel system includes a liquid inlet port, a liquid inlet reservoir, a liquid outlet, and a liquid outlet reservoir, wherein the inlet port is connected to the liquid inlet reservoir, and the inlet port is stored. a liquid pool connected to the liquid inlet end of the sample pool, the liquid discharge end of the sample pool is connected to the liquid discharge end liquid storage tank, and the liquid discharge end liquid storage tank is connected to the liquid outlet; preferably, The flow of liquid is achieved in a manner that creates a negative pressure within the microchannel system.

There are multiple sets of the MZI detection chip, the micro-channel system and the photodetector and detection circuit, forming an array to achieve simultaneous detection of different samples.

The beneficial effects of the invention:

The invention proposes an integrated biochemical sensor based on a ridge optical waveguide, which has high detection sensitivity, strong anti-electromagnetic radiation, strong environmental tolerance, easy processing, low cost and easy miniaturization and integration. When the sample concentration or composition in the sample cell changes, the effective refractive index of the original waveguide arm is changed, so that the phase difference between the two waveguide arms is changed, and the output light intensity changes significantly at the output end due to interference, and the light is detected by the sensor. A strong change can tell the sample change. The invention adopts a ridge optical waveguide for the transmission of the light field. Preferably, the air beam-based beam splitter and the bending structure are combined to realize the beam splitting and the change of the propagation direction in the system, and the beam splitting can be performed. The consistency of the phase, amplitude and polarization direction of the two beams is ensured, so that the exiting light can form stable interference. The above structural design and processing can be on the micron level and can be mass-produced through a mature micro-nano process. The sample can be detected by matching the micro flow channel bonded to the surface of the detecting chip, as well as the fiber holder and the photodetector. In addition, if the chip is arrayed and the micro-channel structure is optimized, simultaneous monitoring of different samples can be performed simultaneously, and the arrayed detection system can also realize quantitative analysis using a monochromatic light source.

DRAWINGS

1 is a schematic structural view of an embodiment of a micro-MZI multi-channel biochemical sensing detection system based on a ridge optical waveguide according to the present invention;

2 is a top plan view of an embodiment of a micro-MZI multi-channel biochemical sensing detection system based on a ridge optical waveguide according to the present invention;

3 is a schematic cross-sectional view of a large-section ridge optical waveguide in an embodiment of the present invention;

4 is a schematic diagram of the MZI multi-channel biochemical sensing detection system of Example 1.

5 is a schematic diagram of the arrayed MZI multi-channel biochemical sensing detection system of Example 2.

Detailed ways

Embodiments of the invention are described in detail below. It is to be understood that the following description is only illustrative, and is not intended to limit the scope of the invention.

Referring to FIG. 1 to FIG. 5, in an embodiment, an integrated biochemical sensor based on a ridge optical waveguide includes an MZI detecting chip formed on the same SOI silicon wafer and a fiber holder 1 bonded to the MZI. Detecting a plurality of polymer cavities formed by the polymer 10 on the surface of the chip, a microchannel system formed from a portion of the plurality of polymer cavities, and optoelectronics disposed in another portion of the plurality of polymer cavities a detector and detection circuit 9, the MZI detection chip comprising a ridge optical waveguide 3, a sample cell 8, a dielectric slot beam splitter 2, and a dielectric slot combiner 5 through which the optical fiber passes through the fiber holder 1 and the ridge An end face of the input end of the optical waveguide 3 is coupled, and an output end of the ridge optical waveguide 3 is coupled to the photodetector and the detecting circuit 9, a wave of the ridge optical waveguide 3 A guide arm is coupled to the sample cell 8, the microchannel system being coupled to the sample cell 8 for replacing a sample within the sample cell 8, the light transmitted by the input of the ridge optical waveguide 3 passing The dielectric trough beam splitter 2 is decomposed into two branch beams, one branch beam is used as a reference signal, and the other branch beam is phase-modulated by the sample in the sample cell, and propagates along the two waveguide arms respectively. The medium trough combiner 5 is merged into a bundle, exits from the output end of the ridge optical waveguide 3, is irradiated on the photodetector and the detecting circuit 9, and the light intensity is detected by the photodetector and the detecting circuit 9. The change and conversion into an electrical signal enables detection of the relevant components or concentrations of the sample within the sample cell 8.

In a preferred embodiment, the MZI detecting chip comprises a first dielectric trench formed on the SOI silicon wafer, preferably an air trench, and the first dielectric trench and the T-shaped optical waveguide 3 The branch is cooperatively formed to form the dielectric beam splitter 2 to divide a beam of light into two beams by total internal reflection, and respectively propagate along the two light propagation channels and complete sample detection.

In a preferred embodiment, the ridge optical waveguide 3 has a plurality of 90° bent structures, and the MZI detecting chip includes a plurality of second dielectric grooves 4 formed on the SOI silicon wafer, preferably air. a groove, the first dielectric groove 4 cooperates with a bend of the ridge optical waveguide 3 to change a propagation direction of light in the MZI detecting chip by a total path by total internal reflection, so that the light is in the predetermined path Propagation to complete sample testing.

In a preferred embodiment, the one waveguide arm is in direct contact with the sample within the sample cell 8, more preferably from the waveguide arm through the sample cell 8.

In a preferred embodiment, the two light propagation channels are symmetrically disposed on opposite sides of the input and output waveguide axes of the ridge optical waveguide.

In a preferred embodiment, the polymer is PDMS and a cavity can be formed therein using an embossed micro-nano process.

In a preferred embodiment, the ridge waveguide is a single mode waveguide. The waveguide portion of the ridge-shaped optical waveguide 2 protrudes from the surface of the base material to have a ridge shape as shown in FIG.

In a preferred embodiment, the fiber holder 1 is on the same axis as the input end of the ridge waveguide, and is formed by deep etching on the surface of the SOI wafer, and has a size equivalent to that of the single mode fiber cladding;

In a preferred embodiment, the photodetector is on the axis of the output of the ridge waveguide.

In a preferred embodiment, the microchannel system includes a liquid inlet, a liquid inlet reservoir 6, a liquid outlet, and a liquid outlet reservoir 7, and the inlet is connected to the inlet. a liquid pool 6, the liquid inlet end liquid storage tank 6 is connected to the liquid inlet end of the sample tank 8, and the liquid discharge end of the sample tank 8 is connected to the liquid discharge end liquid storage tank 7, the liquid discharge end storage The liquid pool 7 is connected to the liquid outlet.

In a preferred embodiment, the circulation of the liquid sample is achieved by creating a negative pressure within the microchannel system.

In a preferred embodiment, the integrated biochemical sensor has a plurality of sets of the MZI detection chip, the microchannel system, and the photodetector and detection circuitry, forming an array to enable simultaneous detection of different samples.

Specific embodiments of the present invention are further described below in conjunction with the accompanying drawings.

Referring to FIG. 1 to FIG. 5, the integrated biochemical sensor based on the ridge optical waveguide includes an MZI detecting chip composed of a ridge optical waveguide 3, an air groove, and a sample cell 8, a micro flow channel system, a fiber holder 1, a photodetector, and detection. Circuit 9. The MZI detecting chip and the optical fiber holder 1 are micro structures processed on a silicon (SOI) silicon wafer on the same insulating substrate; the micro flow channel system is in a polymer cavity bonded to the surface of the chip, the photodetector array and The detection circuit is also in the cavity of the above polymer. The biochemical detection system can convert the change of the sample concentration or composition in the sample cell 8 into a change of the output light intensity, and the change of the light intensity can be detected by the photodetector, thereby obtaining the change of the sample in the sample cell 8. The detection system can be directly used with laser light sources and photodetectors with single-mode fibers, and through arraying, simultaneous detection of different samples can be achieved. The ridge waveguides in the MZI detecting chip are all single mode waveguides. The air channel structure in the MZI detecting chip realizes a beam splitter and a bent waveguide structure by using total internal reflection, and the beam splitter can split a beam of light into two beams, and the beam splitting light intensity is followed by a beam splitter and a ridge-shaped optical waveguide. 3 relative position change, the bent waveguide structure is used to change the direction of light transmission within the chip, the direction change is determined by the relative angle of the waveguide and the air groove axis. The fiber holder 1 and the ridge waveguide input end are on the same axis for easy alignment, and are formed by deep etching on the surface of the SOI sheet, and the size is equivalent to that of the single-mode fiber cladding, and can be packaged by the bonded assembly.

The polymer bonded to the surface of the MZI detecting chip is PDMS (polydimethylsiloxane), and a cavity can be formed therein by an imprinted micro-nano process, and the processed PDMS is bonded to the surface of the detecting chip. The microchannel is in a polymer chamber, the microchannel has a liquid inlet and a liquid outlet, and a liquid storage tank. The circulation of the liquid can be performed by generating a negative pressure in the flow channel, and the micro flow channel system is used to replace the sample cell 8 Sample inside. The photodetector is on the axis of the ridge waveguide output and can be encapsulated by a polymer.

The integrated biochemical sensor can be used directly with laser light sources and photodetectors with single-mode fibers, and through arrays, simultaneous detection of different samples can be achieved.

As shown in FIG. 1 and FIG. 2, after the light emitted by the light source is coupled to the end face of the input end of the ridge optical waveguide 3 via the fiber holder 1 , the light field enters the detection chip for transmission. Splitting at the dielectric slot beam splitter 2, changing the transmission direction through the bent waveguide 4, respectively, passing through two waveguide arms, one of the waveguide arms and the sample The sample in the product pool 8 is in direct contact, and the light is reflected and then emitted along the ridge light wave, and is irradiated on the photodetector and the detecting circuit 9 to complete the transition of the optical signal to the electrical signal.

The following further illustrates with examples:

Example 1

A silicon-on-insulator (SOI) having a top silicon thickness of 10 μm, an insulating layer silicon oxide thickness of 2 μm, and a substrate silicon thickness of 475 μm was selected as a material for fabrication. The ridge waveguide and the air channel structure are obtained by deep ultraviolet exposure and inductively coupled plasma dry etching. As shown in Fig. 4, the tunable laser and single-mode fiber are combined with the input end to form a real-time protein solution concentration detection system. After calibration, the intensity of the emitted light is measured by a photodetector, and the protein concentration of the sample is tested.

Example 2

As shown in FIG. 5, the above detection system is arrayed, and has multiple integrated biochemical sensors (MZI sensor 1, MZI sensor 2, MZI sensor 3, ... MZI sensor n); a monochromatic laser can be used instead of the tunable laser, and Lights of various wavelengths λ ₁ , λ ₂ , λ _{3 ,} ... λ _{n are provided} . At the same time, a plurality of photodetectors PD1, PD2, PD3, ... PDn are used in combination. Through the array of the detection system, the measurement of the emitted light intensity of the test object is realized, and the solution change is quantitatively analyzed.

The above is a further detailed description of the present invention in combination with specific/preferred embodiments, and it is not intended that the specific embodiments of the invention are limited to the description. It will be apparent to those skilled in the art that <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; It belongs to the scope of protection of the present invention.

Claims

An integrated biochemical sensor based on a ridge optical waveguide, comprising: an MZI detecting chip formed on the same SOI silicon wafer, a fiber holder, and a plurality of polymerizations formed by a polymer bonded to the surface of the MZI detecting chip a cavity, a microchannel system formed from a portion of the plurality of polymer cavities, and a photodetector and detection circuit disposed in another portion of the plurality of polymer cavities, the MZI detection chip including a ridge optical waveguide, a sample cell, a dielectric slot beam splitter, and a dielectric slot combiner, through which the optical fiber is coupled to an end face of an input end of the ridge optical waveguide, the ridge optical waveguide being on a propagation path Branching into two waveguide arms forming two light propagation channels, the output of which is coupled to the photodetector and the detection circuit, a waveguide arm of the ridge optical waveguide being coupled to the sample cell The microchannel system is connected to the sample cell for replacing a sample in the sample cell, and light transmitted by the input end of the ridge optical waveguide is decomposed into two branch beams by a dielectric slot beam splitter. One branch beam is used as a reference signal, and the other branch beam is phase-modulated by the sample in the sample cell, and propagates along the two waveguide arms, respectively, and merges into an output beam through the media slot combiner, from the ridge The output end of the shaped optical waveguide exits, and the photodetector and the detecting circuit detect the change of the emitted light intensity and convert it into an electrical signal to realize detection of the relevant component or concentration of the sample in the sample cell.
The integrated biochemical sensor according to claim 1, wherein said MZI detecting chip comprises a first dielectric groove, preferably an air groove, formed on said SOI silicon wafer, said first dielectric groove and said The T-branch of the ridge optical waveguide cooperates to form the dielectric slot beam splitter to split a beam of light into two beams by total internal reflection, respectively propagating along the two light propagation channels and performing sample detection.
The integrated biochemical sensor according to any one of claims 1 to 2, wherein the ridge optical waveguide has a plurality of 90° bending structures, and the MZI detecting chip comprises processing on the SOI silicon wafer. a plurality of second dielectric slots, preferably air slots, the second dielectric slots cooperating with the bends of the ridge optical waveguides to change the direction of propagation of light within the MZI detection chip by a total path using total internal reflection Sample detection is performed to cause light to propagate according to the predetermined path.
The integrated biochemical sensor according to any one of claims 1 to 3, wherein the waveguide arm is in direct contact with the sample in the sample cell.
The integrated biochemical sensor according to any one of claims 1 to 4, wherein the two light propagation channels are symmetrically disposed on both sides of the input/output waveguide axis of the ridge optical waveguide.
An integrated biochemical sensor according to any one of claims 1 to 5, characterized in that The polymer is PDMS, preferably formed into a cavity therein by an embossed micro-nano process.
The integrated biochemical sensor according to any one of claims 1 to 6, wherein the ridge waveguide is a single mode waveguide, and a waveguide portion of the ridge optical waveguide protrudes from a surface of the base material to have a ridge shape.
The integrated biochemical sensor according to any one of claims 1 to 7, wherein the fiber holder and the input end of the ridge waveguide are on the same axis, formed by deep etching on the surface of the SOI wafer, and the size and the single mode. The fiber cladding is equivalent; preferably, the photodetector is on the axis of the output of the ridge waveguide.
The integrated biochemical sensor according to any one of claims 1 to 8, wherein the microchannel system comprises a liquid inlet port, a liquid inlet reservoir, a liquid outlet, and a liquid outlet reservoir. The inlet port is connected to the inlet port reservoir, the inlet port reservoir is connected to the inlet end of the sample cell, and the outlet end of the sample cell is connected to the outlet port reservoir. The liquid discharge port reservoir is connected to the liquid outlet; preferably, the circulation of the liquid is achieved by generating a negative pressure in the microchannel system.
The integrated biochemical sensor according to any one of claims 1 to 9, characterized by comprising a plurality of sets of said MZI detecting chip, said microchannel system, said photodetector and detecting circuit, forming an array to realize Simultaneous detection of different samples.