CN114259203B

CN114259203B - Chip integrated coherence tomography system

Info

Publication number: CN114259203B
Application number: CN202111497037.6A
Authority: CN
Inventors: 闫培光; 李佳桐; 陈浩; 李玲; 杨俊波
Original assignee: Shenzhen University
Current assignee: Shenzhen University
Priority date: 2021-12-08
Filing date: 2021-12-08
Publication date: 2022-12-30
Anticipated expiration: 2041-12-08
Also published as: CN114259203A

Abstract

The invention is suitable for the technical field of enhanced optical imaging and provides a chip integrated coherence tomography system. The chip integrated coherence tomography imaging system comprises an imaging component, a silicon substrate and an adjustable delay coil component arranged on the silicon substrate, wherein the imaging component comprises a light source, a first circulator, a first polarization controller and a beam splitter which are sequentially arranged along the light transmission direction; the imaging assembly further comprises a sample arm and a reference arm which are connected with the beam splitter through optical fibers respectively, the sample arm is connected with a sample information acquisition assembly which transmits sample information back to the beam splitter, the adjustable delay coil assembly is connected to the reference arm and is used for carrying out optical path control on input light and transmitting the processed light back to the beam splitter. According to the invention, the large-range adjustment of the imaging depth of the optical coherence tomography can be realized, and the use requirement can be met.

Description

Chip integrated coherence tomography system

Technical Field

The invention belongs to the technical field of enhanced optical imaging, and particularly relates to a chip integrated coherence tomography imaging system.

Background

Optical coherence tomography is a high resolution, non-contact, non-invasive biological tissue imaging technique. Since the early 90 s of the 20 th century is applied to ophthalmic clinic, the technology obtains images similar to pathological changes of eye tissues in vivo, improves the understanding of the occurrence and development processes of some diseases, is a brand new imaging diagnosis technology after ophthalmic radiation diagnosis, ultrasonic diagnosis and angiography diagnosis, and has led to extensive research by optical coherence tomography with high resolution.

In the related art, the optical path length of the reference arm is increased by using the additional optical fiber length of the reference arm, so that the optical path difference between the reference arm and the sample arm satisfies the deep imaging of the sample. The method effectively increases the imaging depth, but only can image within a certain fixed depth or a small range, cannot realize the adjustment of the imaging depth within a large range, and still has certain use defects.

Disclosure of Invention

In view of this, an embodiment of the present invention provides a chip integrated coherence tomography system to solve the problem that a large-scale imaging depth adjustment cannot be achieved and a certain use defect exists.

In order to solve the above problem, the technical solution of the embodiment of the present invention is implemented as follows:

a chip integrated coherence tomography imaging system comprises an imaging component, a silicon substrate and an adjustable delay coil component arranged on the silicon substrate, wherein the imaging component comprises a light source, a first circulator, a first polarization controller and a beam splitter, the first circulator is used for regulating and controlling the light propagation direction, the first polarization controller is used for controlling a light field mode, the beam splitter is used for receiving light output from the first polarization controller and splitting light, and the light source, the first circulator, the first polarization controller and the beam splitter are connected through optical fibers; the imaging component further comprises a sample arm and a reference arm which are connected with the beam splitter through optical fibers respectively, the sample arm is connected with a sample information acquisition component which can transmit sample information back to the beam splitter, the adjustable delay coil component is connected to the reference arm, and the adjustable delay coil component is used for controlling the optical path of input light and transmitting processed light back to the beam splitter.

In some embodiments, the adjustable delay coil assembly comprises a second circulator, a first Mach-Zehnder modulator, a second Mach-Zehnder modulator, a third Mach-Zehnder modulator and a third circulator which are arranged in sequence along the propagation direction of light and connected in series, and a return optical fiber is connected between the second circulator and the third circulator; and silicon nitride waveguide adjustable delay coils with different delay amounts are connected between the first Mach-Zehnder modulator and the second Mach-Zehnder modulator, between the second Mach-Zehnder modulator and the third Mach-Zehnder modulator, and between the third Mach-Zehnder modulator and the third circulator.

In some embodiments, the first mach-zehnder modulator, the second mach-zehnder modulator, and the third mach-zehnder modulator each include a control electrode for controlling a propagation path of light.

In some embodiments, the silicon nitride waveguide tunable delay coil includes a coil body having a receiving cavity formed therein.

In some embodiments, the silicon nitride waveguide tunable delay coil further comprises a waveguide electrode disposed within the receiving cavity.

In some embodiments, the wave conductive electrode is covered with a layer of non-linear dielectric material.

In some embodiments, the imaging assembly further comprises a reflector for receiving light emitted by the third circulator and reflecting the light back to the third circulator, and the reflector and the third circulator are connected by an optical fiber.

In some embodiments, a second polarization controller for controlling the light field mode is further disposed on the optical fiber between the beam splitter and the second circulator.

In some embodiments, the sample information collecting assembly includes a third polarization controller, an optical fiber delay coil for adjusting the optical path matching degree on the sample arm, and an adjustable focal length lens group for collecting sample information, which are sequentially arranged along the light propagation direction and connected through an optical fiber, and the adjustable focal length lens group is arranged opposite to the sample to be measured at an interval.

In some embodiments, the imaging assembly further comprises a receiver for receiving information from the sample returned from the beam splitter, the receiver being connected to the first circulator by an optical fiber.

The chip integrated coherence tomography imaging system provided by the embodiment of the invention comprises an imaging component, a silicon substrate and an adjustable delay coil component arranged on the silicon substrate, wherein the adjustable delay coil component is used for carrying out optical path control on input light and transmitting the processed light back to a beam splitter. Like this, through being provided with adjustable delay coil assembly, controlling adjustable delay coil assembly's mode, alright realization is to the accurate control of optical path length size, makes the length of the reference arm in the testing process can adjust as required, and accommodation range is wide moreover, adjusts the precision height, can realize that optics coherence tomography imaging depth is adjustable on a large scale. Moreover, the chip integrated coherence tomography imaging system is small in size, compact in structure, convenient to produce and capable of meeting use requirements.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a chip-integrated coherence tomography system provided by an embodiment of the invention;

FIG. 2 is a schematic view of a silicon-based layer according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a silicon nitride waveguide tunable delay coil according to an embodiment of the present invention.

Description of the reference numerals:

1. a chip integrated coherence tomography system; 10. a sample; 11. a silicon base layer; 111. a silicon substrate; 112. a silicon dioxide buried oxide layer; 113. a silicon nitride layer; 12. an imaging assembly; 121. a light source; 122. a first circulator; 123. a first polarization controller; 124. a beam splitter; 125. a sample arm; 126. a reference arm; 13. a sample information acquisition component; 131. a third polarization controller; 132. a fiber delay coil; 133. a variable focal length lens group; 14. an adjustable delay coil assembly; 140. a control electrode; 141. a second circulator; 142. a first Mach-Zehnder modulator; 143. a second Mach-Zehnder modulator; 144. third mach-zehnder modulation; 145. a third circulator; 146. a return optical fiber; 147. a silicon nitride waveguide adjustable delay coil; 1471. a coil body; 1472. a receiving cavity; 1473. a waveguide electrode; 1474. a layer of non-linear dielectric material; 15. a reflector; 16. a second polarization controller; 17. a receiver.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The individual features described in the embodiments can be combined in any suitable manner without departing from the scope, for example different embodiments and solutions can be formed by combining different features. Various possible combinations of the various specific features of the invention are not described in detail to avoid unnecessary repetition.

It should be noted that the terms of orientation such as left, right, up and down in the embodiments of the present invention are only relative to each other or are referred to the normal use state of the product, and should not be considered as limiting.

As shown in fig. 1 and fig. 2, a chip-integrated coherence tomography system 1 according to an embodiment of the present invention includes an imaging component 12, a silicon substrate 11, and an adjustable delay coil component 14 disposed on the silicon substrate 11. The silicon-based layer 11 includes a silicon substrate 111 at the bottom layer, a buried oxide layer of silicon dioxide 112 at the middle layer, and a silicon nitride waveguide layer 113 at the top layer. The imaging assembly 12 includes a light source 121, a first circulator 122, a first polarization controller 123 and a beam splitter 124, wherein the first circulator 122, the first polarization controller 123 and the beam splitter 124 are sequentially arranged along a light transmission direction and used for regulating a light propagation direction, the first polarization controller 123 is used for controlling a light field mode, the beam splitter 124 is used for receiving and splitting light output from the first polarization controller 123, and the light source 121, the first circulator 122, the first polarization controller 123 and the beam splitter 124 are all connected through optical fibers; the imaging assembly 12 further includes a sample arm 125 and a reference arm 126 respectively connected to the beam splitter 124 through optical fibers, the sample arm 125 is connected to a sample information collecting assembly 13 capable of transmitting sample information back to the beam splitter 124, the adjustable delay coil assembly 14 is connected to the reference arm 126, and the adjustable delay coil assembly 14 is configured to perform optical path control on input light and transmit processed light back to the beam splitter 124. Specifically, the light source 121 provides a signal to the system to the light source 121, and the specific wavelength of the light source 121 can be changed according to different samples. Light emitted by the light source 121 is transmitted into the first circulator 122 through an optical fiber, the light can only propagate in one direction in the first circulator 122, the light is emitted from the first circulator 122 and enters the first polarization controller 123, the input light is kept in a TE mode through the first polarization control, and in the beam splitter 124, the beam splitter 124 can be selected as a wide-spectrum optical fiber beam splitter 124, and the light can be split into light beams with the same frequency and phase. The beam intensity is split 3: 1 by beam splitter 124 and enters sample arm 125 and reference arm 126, respectively. A sample information collection assembly 13 is provided on the sample arm 125. The sample information acquisition assembly 13 can acquire sample phase information over a wide range of depths. And returns to the beam splitter 124 along the optical path after the sample phase information is collected. The adjustable delay coil assembly 14 disposed on the reference arm 126 can control the optical path of the light beam in a wide range and precisely according to the detection requirement, and transmit the regulated light beam back to the beam splitter 124. Thus, the light returning from the sample information collection unit 13 and the light returning from the adjustable delay coil unit 14 interfere in the beam splitter 124, and the interference information is output to the receiver 17 after passing through the first circulator 122, and finally forms an image through the calculation processing unit.

The chip integrated coherence tomography imaging system 1 provided by the embodiment of the present invention can realize accurate control of the optical path length by controlling the working mode of the adjustable delay coil assembly 14, so that the length of the reference arm 126 in the detection process can be adjusted as required, and the adjustment range is wide, the adjustment accuracy is high, and the wide-range adjustment of the imaging depth of the optical coherence tomography imaging can be realized. Moreover, the chip integrated coherence tomography imaging system 1 is small in size, compact in structure, convenient to produce and capable of meeting use requirements.

As shown in fig. 2, in some embodiments, the thickness of the silicon substrate 111 is set to 600 μm, the thickness of the silicon dioxide buried oxide layer 112 is set to 2-3 μm, and the thickness of the silicon nitride waveguide layer 113 at the top layer is set to 0.3-1 μm, so as to reliably meet the setting requirement of the whole system structure.

As shown in fig. 1, in some embodiments, the tunable delay coil assembly 14 includes a second circulator 141, a first mach-zehnder modulator 142, a second mach-zehnder modulator 143, a third mach-zehnder modulator 144, and a third circulator 145 arranged in series along the direction of light propagation and connected in series by optical fibers, with a return fiber 146 connected between the second circulator 141 and the third circulator 145. Silicon nitride waveguide adjustable delay coils 147 having different delay amounts are connected between the first mach-zehnder modulator 142 and the second mach-zehnder modulator 143, between the second mach-zehnder modulator 143 and the third mach-zehnder modulator 144, and between the third mach-zehnder modulator 144 and the third circulator 145. Specifically, the arrangement of the second circulator 141 and the third circulator 145 can control the propagation direction of the light, so as to prevent the light finally emitted from the third circulator 145 from being converted into reflected light and then entering the silicon nitride waveguide adjustable delay coil 147 again. The silicon nitride waveguide tunable delay coil 147 is a waveguide coil designed by a silicon nitride waveguide in a periodic structure, and due to the increase of the waveguide length, the distance of light propagation in the waveguide is also increased, thereby increasing the optical length. Thus, the fixed increase of the optical distance can be controlled by adjusting the number of the coils connected. The first mach-zehnder modulator 142, the second mach-zehnder modulator 143, and the third mach-zehnder modulator 144 are respectively used for controlling the access of the adjustable delay coil of the silicon-oxide waveguide connected at the corresponding positions. With this arrangement, the light emitted from the second circulator 141 propagates in the direction in which the first mach-zehnder modulator 142, the second mach-zehnder modulator 143, the third mach-zehnder modulator 144, and the third circulator 145 are located, and the length of the optical path can be controlled by controlling the three mach-zehnder modulators according to the use requirement. That is, when the first mach-zehnder modulator 142 is turned on, the light is transmitted to the silicon nitride waveguide adjustable delay coil 147 provided between the first mach-zehnder modulator 142 and the second mach-zehnder modulator 143, passes through the silicon nitride waveguide adjustable delay coil 147, and is transmitted in accordance with the turning on or off of the second mach-zehnder modulator 143. When the second mach-zehnder modulator 143 is in the off state, the light is directly transmitted to the third mach-zehnder modulator 144; when the second mach-zehnder modulator 143 is turned on, the light is transmitted to the silicon nitride waveguide adjustable delay coil 147 disposed between the second mach-zehnder modulator 143 and the third mach-zehnder modulator 144, and finally transmitted to the third mach-zehnder modulator 144. At this time, transmission is performed again in accordance with the on/off state of the third mach-zehnder modulator 144. When the third mach-zehnder modulator 144 is in the off state, the light is directed into the third circulator 145; when the third mach-zehnder modulator 144 is in the on state, the light is transmitted to the silicon nitride waveguide tunable delay coil 147 disposed between the third mach-zehnder modulator 144 and the third circulator 145, and finally transmitted to the third circulator 145. Thus, the number of the silicon nitride waveguide adjustable delay coils 147 through which the light passes is controlled, so that the control of the whole optical path is realized, and the purpose of controlling the total length of the optical path is achieved.

In some embodiments, the number of mach-zehnder modulators and the number of silicon nitride waveguide tunable delay coils 147 disposed between two adjacent mach-zehnder modulators may be selected according to design requirements, and is not limited herein. When the number of the silicon nitride waveguide adjustable delay coils 147 provided between the two mach-zehnder modulators is two or more, the silicon nitride waveguide adjustable delay coils 147 are provided in series.

As shown in fig. 1, in the embodiment of the invention, the waveguide lengths of the silicon nitride waveguide adjustable delay coils 147 are all Δ L, one silicon nitride waveguide adjustable delay coil 147 is disposed between the first mach-zehnder modulator 142 and the second mach-zehnder modulator 143, two silicon nitride waveguide adjustable delay coils 147 are disposed between the second mach-zehnder modulator 143 and the third mach-zehnder modulator 144, and four silicon nitride waveguide adjustable delay coils 147 are disposed between the third mach-zehnder modulator 144 and the third circulator 145 according to the design requirement. Thus, the system can realize the control of the delay amount of 0 to 7 Δ L. Of course, the Δ L length can be modified technically through specific application, and the number of settings can be adjusted, so that different optical paths can be obtained, a large-range delay amount of the optical paths is realized, and different use requirements are met.

As shown in FIG. 1, in some embodiments, the first Mach-Zehnder modulator 142, the second Mach-Zehnder modulator 143, and the third Mach-Zehnder modulator 144 each include a control electrode 140 thereon for controlling the path of light propagation. The voltage applied to the control electrode 140 is used to control whether the silicon nitride waveguide adjustable delay coil 147 is connected to the optical path, so as to change the number of the silicon nitride waveguide adjustable delay coils 147 connected to the optical path, thereby achieving the purpose of controlling the total length of the optical path.

As shown in fig. 1 and 3, in some embodiments, the silicon nitride waveguide tunable delay coil 147 includes a coil body 1471 with a receiving cavity 1472 formed within the coil body 1471. Specifically, the coil body 1471 is a waveguide coil designed in a periodic structure by a silicon nitride waveguide, and the distance of light propagation in the waveguide is also increased due to the increase in the length of the waveguide. In this way, the coil body 1471 is wound in a desired shape according to design requirements, and an effect of increasing the optical path length is achieved. In the embodiment of the present invention, a housing cavity 1472 is formed in the coil body 1471 at a middle position by winding.

As shown in fig. 3, in some embodiments, the silicon nitride waveguide tunable delay coil 147 further includes a waveguide electrode 1473, the waveguide electrode 1473 being disposed within the housing cavity 1472. The waveguide electrodes 1473 are arranged to apply an electric field across the waveguide to change the effective refractive index of the waveguide and thus change the optical path length. Thus, by controlling the optical path length in the single silicon nitride waveguide adjustable delay coil 147, the fine adjustment of the optical path length in a certain range can be realized, and the adjustment range and the adjustment accuracy of the whole optical path length control are improved.

As shown in fig. 3, in some embodiments, the waveguide electrode 1473 is covered with a layer 1474 of a non-linear dielectric material. The layer of nonlinear dielectric material 1474 serves to enhance the kerr effect of the waveguide, making the electrical modulation effect more pronounced. Thus, after the waveguide electrode 1473 on each silicon nitride waveguide adjustable delay coil 147 is energized, the effective refractive index of the waveguide changes under the action of the electric field and the nonlinear dielectric material, so that the optical path can be changed in a small range. Of course, the silicon nitride waveguide layer 113 may also be covered with a layer of nonlinear dielectric material 1474 to improve performance. Specifically, the nonlinear dielectric material can be prepared on the waveguide of the silicon nitride waveguide adjustable delay coil 147 by a wet transfer method or a physical vapor deposition method, so that the electrical modulation effect is improved. The non-linear dielectric material can be graphene, transition metal sulfide (such as two-dimensional materials of molybdenum disulfide, tungsten disulfide and the like) and the like.

As shown in FIG. 1, in some embodiments, the imaging assembly 12 further comprises a reflector 15 for receiving light emitted by the third circulator 145 and reflecting the light back to the third circulator 145, wherein the reflector 15 and the third circulator 145 are connected by an optical fiber. So arranged, light exiting the third circulator 145 is directed towards the emitter, and the reflector 15 re-enters the reflected light into the third circulator 145 along the optical path. The second circulator 141 and the third circulator 145 can control the entering light and the reflected light entering again to be not interfered with each other. Thus, the reflected light entering the third circulator 145 enters the return fiber 146 from the output port, passes into the second circulator 141, and finally enters the beam splitter 124.

As shown in FIG. 1, in some embodiments, a second polarization controller 16 for controlling the light field mode is also disposed on the fiber between the beam splitter 124 and the second circulator 141. By setting the second polarization control, the reflected light is still in a TE mode, and the accuracy of a result is improved. The TE mode is a propagation mode in which the longitudinal direction of an electric field is zero and the longitudinal component of a magnetic field is not zero in the propagation direction of electromagnetic waves.

As shown in fig. 1, in some embodiments, the sample information collecting assembly 13 includes a third polarization controller 131 connected by optical fibers, a fiber delay coil 132 for adjusting the optical matching degree on the sample arm 125, and an adjustable focal length lens set 133 for collecting sample information, wherein the adjustable focal length lens set 133 is disposed opposite to the sample 10 to be measured at a distance. Thus arranged, the arrangement of the third polarization controller 131 ensures that the incident light and the reflected light are TE modes. The fiber delay coil 132 is a fixed-length coil made of optical fiber, and the optical path length of the reference arm 126 and the optical path length of the sample arm 125 can be matched by fixing the length of the fiber delay coil 132. Specifically, the adjustable focal length lens set 133 focuses the light to illuminate the sample 10, the light is reflected and scattered at the sample 10, and the signal light is received by the adjustable focal length lens set and then returned to the beam splitter 124 along the optical path. The number of the required adjustable delay coils 147 can be accessed according to the optical path difference required by the adjustable focal length lens set 133, so that the optical path difference between the sample arm 125 and the reference arm 126 is in a proper size. Different voltages are applied by connecting the waveguide electrode 1473 on the silicon nitride waveguide adjustable delay coil 147, so that the imaging image can be adjusted in a deeper or shallower range at the observation depth.

As shown in FIG. 1, in some embodiments, imaging assembly 12 further includes a receiver 17 for receiving information from beam splitter 124 and containing the sample, receiver 17 being coupled to first circulator 122 by an optical fiber. The receiver 17 forms an image by the received light containing the sample detection information through the calculation processing unit, and finally outputs the processed sample information to finish the detection.

The chip integrated coherence tomography system 1 provided in the embodiment of the present invention can adjust the variation of the overall optical path in a large range by adjusting the number of the adjustable delay coils 147 connected to the silicon nitride waveguide, and can adjust the overall optical path in a certain range by applying a voltage to the waveguide electrode 1473 connected to the coil, thereby achieving a large-range and fine adjustment function. The chip integrated coherence tomography imaging system 1 utilizes the characteristics of low transmission loss of silicon nitride, a wider transparent window and the like to ensure that the loss of light in the silicon nitride waveguide adjustable delay coil 147 is very low, so that the overall power consumption of the chip integrated coherence tomography imaging system 1 is reduced, and the system can be adapted to most of light sources 121 on the market due to the transparent window of 0.4-8 um of silicon nitride. Meanwhile, the chip integrated coherence tomography imaging system 1 has the advantages of small size and compact structure through silicon-based integration, is easy to produce in a large scale in actual manufacturing, and has good economic benefit.

The working mode of the chip integrated coherence tomography imaging system 1 provided by the embodiment of the invention is as follows:

coherent light from the light source 121 passes through the first circulator 122 and enters the first polarization controller 123, the first polarization controller 123 controls the input light to be in the TE mode, and then enters the beam splitter 124 to split the light into two beams, the splitting ratio is 3: 1 between the intensity of the sample arm 125 and the intensity of the reference arm 126, and the ratio can be changed according to different samples 10 to be measured. The light in the sample arm 125 passes through the third polarization controller 131 to ensure that the light is still TE mode, and then the light enters the lens group with adjustable focal length after passing through the optical fiber delay coil 132, the lens group with adjustable focal length focuses the light and then irradiates the sample 10, the light is reflected and scattered at the sample 10, and the signal light returns to the beam splitter 124 along the light path after being received by the lens group with adjustable focal length. The light in the reference arm 126 is emitted from the beam splitter 124 and then reaches the second circulator 141 through the second polarization controller 16, and then when the light passes through the first mach-zehnder modulator 142, the voltage on the first mach-zehnder modulator 142 can be changed to control whether the light passes through the silicon nitride waveguide adjustable delay coil 147, and when the three mach-zehnder modulators control the light path not to pass through the silicon nitride waveguide adjustable delay coil 147, the delay amount is zero. When light passes through the silicon nitride waveguide adjustable delay coil 147, the optical path switching can be realized by adjusting the voltage of the control electrode 140 on the first mach-zehnder modulator 142, the second mach-zehnder modulator 143, and the third mach-zehnder modulator 144, and if the increased optical path of each silicon nitride waveguide adjustable delay coil 147 is Δ L, the system can realize a delay amount of 0 to 7 Δ L. In addition, after each silicon nitride waveguide adjustable delay coil 147 is powered on, the effective refractive index of the waveguide changes under the action of an electric field and a nonlinear dielectric material, so that the optical path is changed in a small range. The light enters the third circulator 145 after passing through the last silicon nitride waveguide tunable delay coil 147 and travels along the optical path to the reflector 15, where the reflected light travels along the optical path again to the third circulator 145 and travels through the output port to the second circulator 141 and returns along the optical path to the second polarization controller 16 and the beam splitter 124. The second polarization controller 16 ensures that the reflected light is still in the TE mode. The reference light and the sample light interfere at the beam splitter 124, the interference information enters the receiver through the first circulator 122, and after an image is formed by the calculation processing unit, the sample information is processed and output.

The above description is intended to be illustrative of the preferred embodiment of the present invention and should not be taken as limiting the invention, but rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Claims

1. A chip integrated coherence tomography imaging system is characterized by comprising an imaging component, a silicon substrate and an adjustable delay coil component, wherein the adjustable delay coil component is arranged on the silicon substrate, the silicon substrate comprises a silicon substrate positioned at the bottom layer, a silicon dioxide buried oxide layer positioned at the middle layer and a silicon nitride waveguide layer positioned at the top layer; the imaging assembly further comprises a sample arm and a reference arm which are connected with the beam splitter through optical fibers respectively, the sample arm is connected with a sample information acquisition assembly which transmits sample information back to the beam splitter, the adjustable delay coil assembly is connected with the reference arm, and the adjustable delay coil assembly is used for carrying out optical path control on input light and transmitting processed light back to the beam splitter; the adjustable delay coil assembly comprises a second circulator, a first Mach-Zehnder modulator, a second Mach-Zehnder modulator, a third Mach-Zehnder modulator and a third circulator which are sequentially arranged along the light propagation direction and connected in series through optical fibers, return optical fibers are connected between the second circulator and the third circulator, silicon nitride waveguide adjustable delay coils with different delay amounts are connected between the first Mach-Zehnder modulator and the second Mach-Zehnder modulator, between the second Mach-Zehnder modulator and the third Mach-Zehnder modulator, and between the third Mach-Zehnder modulator and the third circulator, the silicon nitride waveguide adjustable delay coils are designed according to a periodic structure through silicon nitride waveguides, and the waveguide lengths of the silicon nitride waveguide adjustable delay coils are the same.

2. The chip-integrated coherence tomography system of claim 1, wherein the first mach-zehnder modulator, the second mach-zehnder modulator, and the third mach-zehnder modulator each include a control electrode for controlling a light propagation path.

3. The chip integrated coherence tomography imaging system of claim 2, wherein the silicon nitride waveguide adjustable delay coil comprises a coil body having a receiving cavity formed therein.

4. The chip integrated coherence tomography system of claim 3, wherein the silicon nitride waveguide tunable delay coil further comprises a waveguide electrode disposed within the receiving cavity.

5. The chip integrated coherence tomography system of claim 4, wherein the waveguide electrode is covered with a layer of non-linear dielectric material.

6. The on-chip integrated coherence tomography system of any one of claims 1 to 5, wherein the imaging assembly further comprises a reflector for receiving light emitted by the third circulator and reflecting the light back to the third circulator, the reflector and the third circulator being connected by an optical fiber.

7. The chip integrated coherence tomography system of any one of claims 1 to 5, wherein a second polarization controller for controlling light field modes is further disposed on the optical fiber between the beam splitter and the second circulator.

8. The chip-integrated coherence tomography system of any one of claims 1 to 5, wherein the sample information collection assembly comprises a third polarization controller, a fiber delay coil for adjusting the optical path matching degree on the sample arm, and an adjustable focal length lens set for collecting sample information, the third polarization controller, the fiber delay coil and the adjustable focal length lens set are arranged in sequence along the light propagation direction and are connected through an optical fiber, and the adjustable focal length lens set is arranged opposite to the sample to be measured at a distance.

9. The on-chip integrated coherence tomography system of any one of claims 1 to 5, wherein the imaging assembly further comprises a receiver for receiving the sample information returned from the beam splitter, the receiver being connected to the first circulator by an optical fiber.