CN203290875U - Bifocal binocular optical coherence tomography (OCT) real-time imaging system on basis of ring cavity frequency sweep - Google Patents

Abstract

The utility model discloses a dual-focus full-eye OCT real-time imaging system based on ring cavity frequency sweeping. The system is based on the ring cavity frequency sweep OCT system. A half-wave plate is set in the cavity to realize the polarization state switching of the two linearly polarized light during odd and even light cycles; and a polarization beam splitter is set in the sample arm to construct two initial zeros of the P-channel light and the S-channel light. The optical path reference plane and different light focusing positions; finally, different carrier frequencies are used to distinguish the P-channel light and S-channel light of different ring cavity orders, so that only a single high-bandwidth balanced photodetector can realize OCT of the whole eye Alias-free high-precision stitching of images. Since the system generates multiple reference planes with zero optical path through the method of light circulation, real-time imaging of the whole eye can be realized. In addition, due to the dual-focus sample arm design, high-sensitivity imaging in the whole eye range can be realized.

Description

A dual-focus whole-eye OCT real-time imaging system based on ring cavity frequency sweep

technical field

The utility model relates to optical coherence tomography (OCT) technology, in particular to a dual-focus whole-eye OCT real-time imaging system based on ring cavity frequency sweep. the

Background technique

Accommodation is the ability of the human eye to change the refractive state of the eye in order to see close objects clearly, and it can make close objects clearly imaged on the retina. There are many factors that affect the refractive state, including the corneal system, lens system, and eye axis. The eye axis is one of the important factors affecting the refractive state of the eye. Axial length was defined as the distance from the anterior surface of the cornea to the anterior surface of the retina. The enlargement of the axial length of the eye will directly lead to the myopia of the eyeball. Therefore, it has attracted the attention of more and more research groups. the

Optical coherence tomography (OCT) is a non-invasive, non-contact medical imaging method based on low-coherence interference. This technique is very suitable for quantitatively detecting the dynamic changes of the surface morphology, system thickness and position of each system before and after the eye changes the refractive state. Since 1994, Izatt et al. first applied OCT technology to cornea and anterior segment imaging, and now it has become an ideal tool for measuring and analyzing anterior segment tissue and structure, and can be used to diagnose abnormal lesions of cornea, iris, anterior chamber angle and other tissues. It is especially helpful for the diagnosis and research of glaucoma, cataract and other common eye diseases. This technology is also widely used in the research of regulation and the pathogenesis of presbyopia. However, since the time-domain system cannot perform one-time dynamic imaging of the entire eye (including the cornea, iris, anterior chamber, lens, and retina), it cannot meet the application requirements of higher-speed whole-eye imaging. the

In recent years, more and more research groups have implemented whole-eye imaging using novel Fourier-domain OCT techniques (including spectral-domain OCT and frequency-swept OCT). Traditional Fourier domain OCT is limited by the imaging depth (usually about 6-7mm), so it cannot meet the needs of whole-eye imaging (the axial scale is about 37mm). Therefore, in order to realize fast optical coherence tomography of the whole eye, several research groups have proposed various improved schemes. Cuixia Dai et al. proposed to use dual CCD detectors and dual reference arms to implement whole-eye imaging. However, this solution requires two CCDs, so the system cost is too high; Marco Ruggeri et al. proposed to use high-speed scanning vibration in the reference arm Mirror, by scanning multiple reference mirrors at different positions, time-sharing imaging of multiple zero-path reference planes within the entire eye range is realized. Since the system uses scanning galvanometers to realize the switching of multiple zero-path reference planes and the time-sharing acquisition of interference signals, the bottleneck of the system is mainly the speed at which the scanning galvanometers switch reference mirrors (the average time is about 200 μs), so it does not For higher speed whole-eye imaging applications. In addition, since the scanning galvanometer may introduce additional optical path errors in the process of switching multiple reference mirrors, the accuracy of its measurement of the axial length of the eye will also be affected; Hyuu-Woo Jeong et al. Combining with polarization-sensitive OCT technology to achieve time- and step-by-step imaging of the entire anterior segment and retina, this technology greatly improves the switching speed compared with the technical solution using scanning galvanometers, and can theoretically reach a switching frequency of 1MHz, but It still cannot meet the higher-speed real-time imaging requirements of the whole eye structure. Moreover, the system is limited in spectral resolution and cannot image the lens portion of the anterior segment. The Fujimoto group of the Massachusetts Institute of Technology in the United States adopted a swept-frequency light source based on vertical cavity surface emission, which has good instantaneous linewidth and can quickly image the entire eye structure. However, the swept source is still in the laboratory research stage, and the excessive coherence length may also introduce greater autocorrelation noise, thereby affecting the imaging quality of the whole eye, and the system is realized by sacrificing the lateral resolution of the system Whole-eye imaging. the

Contents of the invention

Aiming at the deficiencies of the prior art, the utility model provides a bifocal whole-eye OCT real-time imaging system based on ring cavity frequency sweep. The purpose of this utility model is achieved through the following technical solutions:

The utility model proposes a dual-focus full-eye OCT real-time imaging system based on ring cavity frequency sweep: including a frequency sweep light source, a first single-mode fiber coupler, a second single-mode fiber coupler, a third single-mode fiber coupler, Fourth single-mode fiber coupler, polarization maintaining fiber coupler, first fiber adapter, second fiber adapter, polarization switcher, first acousto-optic frequency shifter, second acousto-optic frequency shifter, first semiconductor optical amplifier , the second semiconductor optical amplifier, the first optical delay line, the second optical delay line, the first polarization beam splitter, the second polarization beam splitter, the third polarization beam splitter, polarization maintaining fiber circulator, single mode fiber circulator , the first fiber collimator, the second fiber collimator, the third fiber collimator, the polarization beam splitter, the rectangular prism, the first mirror, the second mirror, the scanning mirror, the first lens, the second lens , the third lens, the whole eye to be tested, the first polarization controller, the second polarization controller, the third polarization controller, Mach-Zehnder interferometer type calibration unit, high-bandwidth balanced photodetector, high-speed data acquisition card and computer . the

The frequency-sweeping light source is respectively connected to the input end of the Mach-Zehnder interferometer type calibration unit and the input end of the second single-mode fiber coupler through the first single-mode fiber coupler, and the circuit output end of the Mach-Zehnder interferometer type calibration unit It is connected with one of the input signal channels of the high-speed data acquisition card; the two output ends of the second single-mode fiber coupler are respectively connected to the input end of the first polarization controller and one of the input ends of the third single-mode fiber coupler connection; the first polarization controller is connected to the input end of the first optical fiber adapter, and the output end of the first optical fiber adapter is connected to one of the input ends of the polarization-maintaining fiber coupler; one of the output ends of the polarization-maintaining fiber coupler is connected to the polarization state The input end of the switcher, the output end of the polarization state switcher is connected to the input end of the first acousto-optic frequency shifter, the output end of the first acousto-optic frequency shifter is connected to the input end of the first semiconductor optical amplifier, and the first semiconductor optical amplifier The output end of the polarization-maintaining fiber coupler is connected to the other input end of the polarization-maintaining fiber coupler to form a gain-compensated optical path mismatch recirculation cavity capable of switching different polarization states under even and odd optical recirculation states. The other output end of the polarization maintaining fiber coupler is connected to the input end of the first polarization beam splitter; one of the output ends of the first polarization beam splitter is connected to the input end of the first optical path delay line, and the other output end is connected to the second One of the input ends of the polarization beam splitter is connected, the output end of the first optical path delay line is connected to the other input end of the second polarization beam splitter, and the output end of the second polarization beam splitter is connected to the input of the polarization maintaining fiber circulator end. The first output end of the polarization maintaining fiber circulator is connected to the input end of the third polarization beam splitter, and the two output ends of the third polarization beam splitter are respectively connected to the first fiber collimator and the second fiber collimator; the polarization maintaining fiber circulator The second output end of the device is connected to the input end of the second fiber optic adapter, and the output end of the second fiber optic adapter is connected to one of the input ends of the fourth single-mode fiber coupler; one of the output ends of the third single-mode fiber coupler is connected to the first The input end of the second acousto-optic frequency shifter, the output end of the second acousto-optic frequency shifter is connected to the input end of the second semiconductor optical amplifier, the output end of the second semiconductor optical amplifier is connected to the input end of the second polarization controller, and the second The output end of the polarization controller is connected to the input end of the second optical path delay line, and the output end of the second optical path delay line is connected to the other input end of the third single-mode fiber coupler to form a reference arm gain-compensated optical path Mismatch circulating cavity, the other output end of the third single-mode fiber coupler is connected to the input end of the single-mode fiber circulator, the first output end of the single-mode fiber circulator is connected to the input end of the third fiber collimator, single-mode The second output end of the fiber circulator is connected to the input end of the third polarization controller, and the output end of the third polarization controller is connected to the other input end of the fourth single-mode fiber coupler; two of the fourth single-mode fiber coupler The output ends are respectively connected to the two input ends of the high-bandwidth balanced photodetector, and the circuit output end of the high-bandwidth balanced photodetector is connected to another input signal channel of the high-speed data acquisition card; the output end of the high-speed data acquisition card is connected to the computer connected. The trigger signal output end of the frequency-sweeping light source is connected with the trigger signal input end of the high-speed data acquisition card. the

After the low-coherence light emitted by the frequency-sweeping light source enters the first single-mode fiber coupler, part of the light enters the Mach-Zehnder interferometer type calibration unit, and the other part of the light passes through the second single-mode fiber coupler and is divided into two paths, one of which passes through the first A polarization controller and the first fiber adapter enter the polarization maintaining fiber coupler, and the other light enters the third single-mode fiber coupler; the light entering the polarization maintaining fiber coupler splits a part of the light into the first polarization splitter, and passes through the second The light from one polarization beam splitter is divided into two paths, one path enters the second polarization beam splitter through the delay line of the first optical path, and the other path directly enters the second polarization beam splitter, and the light emitted from the second polarization beam splitter enters the polarization maintaining fiber circulator The light entering the polarization maintaining fiber circulator enters the input end of the third polarization beam splitter through the first output end, and the light exiting from the third polarization beam splitter enters the first fiber collimator and the second fiber collimator respectively The input end of the device; the light emitted from the first fiber collimator passes through the polarization beam splitter prism, the scanning galvanometer and the first lens and then enters the whole eye to be tested, and the light emitted from the second fiber collimator passes through the right-angle prism, the first lens A mirror, a second lens, a polarization splitter prism, a scanning galvanometer and the first lens are injected into the whole eye to be tested. Since the optical mechanisms of the two paths of light are designed differently, the two paths of light are respectively focused on the anterior segment of the eye and the anterior segment of the eye. retinal area. The light reflected from the whole eye to be tested may be reflected back to the third polarization beam splitter through two collimating mirrors at the same time because its polarization state may be changed by the biological tissue of the eye. Therefore, in order to prevent the generation of false images and improve the detection For efficiency, the optical path difference of the two optical mechanisms needs to be strictly matched. The light reflected from the third polarization beam splitter enters one of the fourth single-mode fiber couplers through the first output end of the polarization-maintaining fiber circulator, the second output end of the polarization-maintaining fiber circulator and the second fiber adapter Input end; another part of the light output from the polarization maintaining fiber coupler passes through the polarization state switcher, the first acousto-optic frequency shifter and the first semiconductor optical amplifier, and then enters the polarization maintaining fiber coupler for the second time, and then enters the polarization maintaining fiber coupler for the second time The light of the fiber coupler is also divided into two parts, which respectively arrive at the fourth single-mode fiber coupler along the above path and enter the polarization-maintaining fiber coupler for the third time, and so on, the N-1th time enters the polarization-maintaining fiber coupler The light also reaches the fourth single-mode fiber coupler along the above path and enters the polarization-maintaining fiber coupler for the Nth time. Similarly, the light entering the third single-mode fiber coupler also splits a part of light into the input end of the single-mode fiber circulator, and the light entering the single-mode fiber circulator enters the third fiber collimator through the first output end and then enters the The light reflected by the third lens and the second reflector enters the fourth single-mode fiber coupler after passing through the first output end, the second output end and the third polarization controller of the single-mode fiber circulator in sequence. Another part of the light output from the third single-mode fiber coupler enters the third single-mode fiber for the second time after passing through the second acousto-optic frequency shifter, the second semiconductor optical amplifier, the second polarization controller and the second optical delay line coupler, the light that enters the third single-mode fiber coupler for the second time is also divided into two parts, respectively arrives at the fourth single-mode fiber coupler along the above-mentioned path and enters the third single-mode fiber coupler for the third time, so that By analogy, the light entering the third single-mode fiber coupler for the N-1th time also reaches the fourth single-mode fiber coupler along the above path and enters the third single-mode fiber coupler for the Nth time. All the above-mentioned light entering the fourth single-mode fiber coupler interferes, and the interference signal is detected by a high-bandwidth balanced photodetector. The interference signal measured by the two-way unit is synchronously collected by a high-speed data acquisition card, and the collected signal is transmitted to the computer. Data processing is carried out in the internal memory, and the output terminal of the high-speed data acquisition card is connected with the computer. the

Compared with background technology, the beneficial effect that the utility model has is:

1. Use ring cavities with different carrier frequencies to spatially encode P-channel light and S-channel light with different ring cavity orders, so that a single high-bandwidth balanced detector can be used to realize interference signal detection and full-eye image stitching without confusion . the

2. Distinguish between P-channel light and S-channel light to realize two different initial zero optical path positions and different focus positions (located in the anterior segment of the whole eye and the retina area respectively) for two different polarization states of light, which is convenient for high-sensitivity detection of the whole eye structure. the

3. Use the Mach-Zehnder interferometer-type calibration unit to collect calibration signals, process signals of multiple different ring cavity levels in frequency bands, and implement Fourier transform at equal wavenumber intervals to facilitate OCT real-time imaging with high axial resolution . the

Description of drawings

Fig. 1 is the structural diagram of the bifocal whole-eye OCT real-time imaging system based on ring cavity frequency sweep described in the utility model;

Fig. 2 is the structural diagram of the polarization state switcher described in the utility model;

Fig. 3 is the schematic diagram of whole-eye imaging of the system described in the utility model;

Fig. 4 is a data processing flowchart of the system described in the utility model. the

Detailed ways

Below in conjunction with accompanying drawing and embodiment example the utility model is described further. the

As shown in Figure 1, the system includes a frequency-sweeping light source 1, a first single-mode fiber coupler 2, a second single-mode fiber coupler 3, a third single-mode fiber coupler 10, a fourth single-mode fiber coupler 35, Polarization maintaining fiber coupler 6, first optical fiber adapter 5, second optical fiber adapter 33, polarization switcher 7, first acousto-optic frequency shifter 8, second acousto-optic frequency shifter 11, first semiconductor optical amplifier 9, Second semiconductor optical amplifier 12, first optical delay line 16, second optical delay line 14, first polarization beam splitter 15, second polarization beam splitter 17, third polarization beam splitter 19, polarization maintaining fiber circulator 18 , single-mode fiber circulator 29, first fiber collimator 20, second fiber collimator 21, third fiber collimator 30, polarization beam splitter prism 25, rectangular prism 22, first reflector 23, second reflector Mirror 32, scanning galvanometer 26, first lens 27, second lens 24, third lens 31, whole eye 28 to be measured, first polarization controller 4, second polarization controller 13, third polarization controller 34, Mach-Zehnder interferometer-type calibration unit 37 , high-bandwidth balanced photodetector 36 , high-speed data acquisition card 38 , and computer 39 . the

The frequency-sweeping light source 1 is connected to the input end of the Mach-Zehnder interferometer type calibration unit 37 and the input end of the second single-mode fiber coupler 3 respectively through the first single-mode fiber coupler 2, and the Mach-Zehnder interferometer type calibration unit The circuit output of 37 is connected with one of the input signal channels of high-speed data acquisition card 38; One of the input ends of the coupler 10 is connected; the first polarization controller 4 is connected to the input end of the first optical fiber adapter 5, and the output end of the first optical fiber adapter 5 is connected to one of the input ends of the polarization maintaining fiber coupler 6; One of the output ends of the polarization maintaining fiber coupler 6 is connected to the 7 input ends of the polarization state switcher, and the output end of the polarization state switcher 7 is connected to the input end of the first acousto-optic frequency shifter 8, and the first acousto-optic frequency shifter 8 The output end of the first semiconductor optical amplifier 9 is connected to the input end of the first semiconductor optical amplifier 9, and the output end of the first semiconductor optical amplifier 9 is connected to the other input end of 6 of the polarization-maintaining optical fiber coupler to form a switch between different polarization states with odd and even times of optical circulation. A gain-compensated optical path mismatch loop cavity. The other output of the polarization-maintaining fiber coupler 6 is connected to the input of the first polarization beam splitter 15; one of the output terminals of the first polarization beam splitter 15 is connected to the input of the first optical delay line 16, and the other output end is connected with one of the input ends of the second polarization beam splitter 17, the output end of the first optical delay line 16 is connected with the other input end of the second polarization beam splitter 17, and the output end of the second polarization beam splitter 17 Connect the input end of the polarization maintaining optical fiber circulator 18. The first output end of the polarization maintaining fiber circulator 18 is connected to the input end of the third polarization beam splitter 19, and the two output ends of the third polarization beam splitter 19 are respectively connected to the first fiber collimator 20 and the second fiber collimator 21 The second output end of the polarization-maintaining optical fiber circulator 18 is connected to the input end of the second fiber optic adapter 33, and the output end of the second fiber optic adapter 33 is connected to one of the input ends of the fourth single-mode fiber coupler 35; the third single-mode fiber One of the output ends of the coupler 10 is connected to the input end of the second acousto-optic frequency shifter 11, and the output end of the second acousto-optic frequency shifter 11 is connected to the input end of the second semiconductor optical amplifier 12, and the second semiconductor optical amplifier 12 The output end is connected to the input end of the second polarization controller 13, the output end of the second polarization controller 13 is connected to the input end of the second optical delay line 14, and the output end of the second optical delay line 14 is connected to the third single-mode optical fiber The other input end of the coupler 10 is connected to form a reference arm gain compensation type optical path mismatch loop cavity, and the other output end of the third single-mode optical fiber coupler 10 is connected to the input end of the single-mode optical fiber circulator 29, the single-mode The first output end of the optical fiber circulator 29 is connected to the input end of the third fiber collimator 30, the second output end of the single-mode optical fiber circulator 29 is connected to the input end of the third polarization controller 34, and the third polarization controller 34 The output end is connected to the other input end of the fourth single-mode fiber coupler 35; two output ends of the fourth single-mode fiber coupler 35 are respectively connected to two input ends of the high-bandwidth balanced photodetector 36, and the high-bandwidth balanced photoelectric detector The circuit output end of the detector 36 is connected with another input signal channel of the high-speed data acquisition card 38 ; the output end of the high-speed data acquisition card 38 is connected with the computer 39 . The trigger signal output end of the sweeping light source 1 is connected with the trigger signal input end of the high-speed data acquisition card 38 . the

After the low-coherence light emitted by the frequency-sweeping light source 1 enters the first single-mode fiber coupler 2, part of the light enters the Mach-Zehnder interferometer-type calibration unit 37, and the other part of the light passes through the second single-mode fiber coupler 3 and is divided into two paths. One path of light enters the polarization-maintaining fiber coupler 6 after passing through the first polarization controller 4 and the first fiber adapter 5, and the other path of light enters the third single-mode fiber coupler 10; Enter the first polarization beam splitter 15, the light by the first polarization beam splitter 15 is divided into two paths, one path enters the second polarization beam splitter 17 through the first optical path delay line 16, and the other path directly enters the second polarization beam splitter 17, from The light emitted by the second polarization beam splitter 17 enters the input end of the polarization maintaining optical fiber circulator 18, and the light entering the polarization maintaining optical fiber circulator 18 enters the input end of the third polarization beam splitter 19 through the first output end, from the third polarization beam splitter The light emitted by device 19 enters the input ends of the first fiber collimator 20 and the second fiber collimator 21 respectively; the light emitted from the first fiber collimator passes through polarization beam splitter prism 25, scanning vibrating mirror 26 and first lens After 27, it enters the whole eye 28 to be measured, and the light emitted from the second fiber collimator 21 passes through the rectangular prism 22, the first reflector 23, the second lens 24, the polarization beam splitter prism 25, the scanning vibrating mirror 26 and the first lens After 27, it is injected into the whole eye 28 to be tested. Since the optical mechanism designs of the two paths of light are different, the two paths of light are respectively focused on the anterior segment of the eye and the retina area of the eye. The light reflected back from the whole eye 28 to be measured may be reflected back to the third polarization beam splitter through two collimating mirrors at the same time because its polarization state may be changed by the biological tissue of the eye. Therefore, in order to prevent the generation of false images and improve For detection efficiency, the optical path difference of the two optical mechanisms needs to be strictly matched. The light reflected back from the third polarization beam splitter 19 passes through the first output end of the polarization-maintaining fiber circulator 18, the second output end of the polarization-maintaining fiber circulator 18 and the second optical fiber adapter 33 and injects into the fourth single-mode fiber coupling One of the input ends of the device 35; another part of the light output from the polarization maintaining fiber coupler 6 passes through the polarization state switcher 7, the first acousto-optic frequency shifter 8 and the first semiconductor optical amplifier 9 and then enters the polarization maintaining fiber for the second time Coupler 6, the light that enters the polarization maintaining fiber coupler 6 for the second time is also divided into two parts, respectively arrives at the fourth single-mode fiber coupler 35 along the above-mentioned path and enters the polarization maintaining fiber coupler 6 for the third time, thereby By analogy, the light that enters the polarization-maintaining fiber coupler 6 for the N-1 time also reaches the fourth single-mode fiber coupler 35 along the above path and enters the polarization-maintaining fiber coupler 6 for the N-th time. The same light entering the third single-mode fiber coupler 10 also splits a part of light into the input end of the single-mode fiber circulator 29, and the light entering the single-mode fiber circulator 29 enters the third fiber collimator through the first output port After 30, it enters the third lens 31 and the second reflector 32, and the reflected light passes through the first output end, the second output end and the third polarization controller 34 of the single-mode fiber circulator 29 in sequence, and then enters the fourth polarization controller 34. Single mode fiber coupler 35. Another part of the light output from the third single-mode fiber coupler 10 passes through the second acousto-optic frequency shifter 11, the second semiconductor optical amplifier 12, the second polarization controller 13 and the second optical delay line 14 and enters for the second time The 3rd single-mode fiber coupler 10, the 10 light that enters the 3rd single-mode fiber coupler for the second time is also divided into two parts, respectively arrives the 4th single-mode fiber coupler 35 along the above-mentioned path and the 3rd time enters the 3rd single-mode fiber coupler 35. Single-mode fiber coupler 10, and so on, the light that N-1 enters the 3rd single-mode fiber coupler 10 also arrives the 4th single-mode fiber coupler 35 along the above-mentioned path and enters the 3rd single-mode fiber coupler N time device 10. All the above-mentioned light entering the fourth single-mode fiber coupler 35 interferes, and the interference signal is detected by a high-bandwidth balanced photodetector 36, and the interference signal measured by the two-way unit is synchronously collected by a high-speed data acquisition card 38, and the collected signal It is transmitted to the internal memory of the computer 39 for data processing, and the output end of the high-speed data acquisition card 38 is connected with the computer 39. The trigger signal of the high-speed data acquisition card 38 is generated by the frequency-sweeping light source 1. In the figure, the solid line part is an optical fiber, the dotted line part is a circuit connection line, and the bold solid line part represents a polarization-maintaining optical fiber. the

As shown in Fig. 2, it is the structural diagram of the polarization state switcher described in the utility model, this polarization state switcher comprises the 4th fiber optic collimator mirror 40, half-wave plate 41, the 5th fiber optic collimator mirror 42, sample arm circulation cavity The light in each cycle needs to pass through the fourth fiber collimator 40 to exit, pass through the half-wave plate 41, and then be coupled back to the fiber by the fifth fiber collimator 42. The switching of the polarization state is realized by converting the S-channel light and the P-channel light by the half-wave plate. the

As shown in Figure 3, it is the schematic diagram of the whole-eye imaging of the system described in the utility model; since the sample arm and the reference arm of the frequency-sweeping optical coherence tomography system are respectively provided with gain compensation type optical path loss with different carrier frequency Therefore, based on the extremely high-speed stepping of the reference light and the sample light in the optical path mismatching recirculation cavity, multiple zero-path reference positions will be generated, as shown in Figure 3, respectively a, b, c, d , the odd and even light cycles are for different light polarization states (P light and S light), the light of different polarization states is focused on different positions of the whole eye, and the light of different ring cavity orders corresponds to different depth regions of the whole eye. Therefore, the system enables real-time whole-eye OCT imaging with high sensitivity. In addition, by adjusting the polarization states of different ring cavity-level secondary lights, setting different ring cavity optical path differences, setting different initial zero optical path points, and setting light focusing methods for different channels, we can realize a variety of axial scanning modes, As shown in Figure 3, when N=0, N=2 is the S channel light, N=1, N=3 is the P channel light, there can be 4 axial scanning modes, the same selection when N=0, N =2 is P channel light, N=1, N=3 is S channel light, there are also 4 axial scanning modes. the

As shown in Fig. 4, it is the data processing flowchart of the system described in the present invention, because the amount of carrier frequency is greater than the optical path mismatch of the ring cavity, the multiple data with the whole-eye structure information collected in the depth domain The secondary interference signals of the ring cavity can be completely distinguished in the frequency domain. And in order to avoid the influence of artificial carrier frequency on the sample structure information carried by the original interference signal, and ensure that the axial resolution of the system in the entire eye range is close to the theoretical value. Firstly, the collected calibration interference spectrum signal should be directly interpolated in wavenumber space based on the spectral phase information to obtain enough sampling points of the OCT imaging signal distributed at equal wavenumber intervals; The interferometric spectral signal of the whole eye can be restored by directly performing Fourier transform on the sampling points distributed at equal wavenumber intervals to recover the depth structure information of the whole eye corresponding to the order of the ring cavity; finally, by stitching the OCT images of multiple ring cavity orders , so as to realize the real-time imaging of whole-eye frequency-swept OCT. the

Claims (1)

1. the full eye of the bifocus based on ring cavity frequency sweep OCT Real Time Image System: comprise swept light source, the first single-mode optical-fibre coupler, the second single-mode optical-fibre coupler, the 3rd single-mode optical-fibre coupler, the 4th single-mode optical-fibre coupler, polarization-maintaining fiber coupler, the first fiber adapter, the second fiber adapter, the polarization state switch, first sound optical frequency shift device, rising tone optical frequency shift device, the first semiconductor optical amplifier, the second semiconductor optical amplifier, the first optical path delay line, the second optical path delay line, the first polarizing beam splitter, the second polarizing beam splitter, the 3rd polarizing beam splitter, the polarization maintaining optical fibre device that goes in ring, the single-mode fiber circulator, the first optical fiber collimator, the second optical fiber collimator, the 3rd optical fiber collimator, polarization splitting prism, corner cube prism, the first reflecting mirror, the second reflecting mirror, scanning galvanometer, first lens, the second lens, the 3rd lens, full eye to be measured, the first Polarization Controller, the second Polarization Controller, the 3rd Polarization Controller, Mach-Zehnder interferometer is demarcated unit, high bandwidth balance photodetector, high-speed data acquisition card and computer,

it is characterized in that: swept light source demarcates the input of unit with Mach-Zehnder interferometer respectively by the first single-mode optical-fibre coupler and the input of the second single-mode optical-fibre coupler is connected, and the circuit output end that Mach-Zehnder interferometer is demarcated unit is connected with one of them input signal channel of high-speed data acquisition card, two outfans of the second single-mode optical-fibre coupler are connected with the input of the first Polarization Controller and one of them input of the 3rd single-mode optical-fibre coupler respectively, the first Polarization Controller connects the input of the first fiber adapter, and the outfan of the first fiber adapter is connected with one of them input of polarization-maintaining fiber coupler, one of them outfan of polarization-maintaining fiber coupler connects the input of polarization state switch, the outfan of polarization state switch connects the input of first sound optical frequency shift device, the outfan of first sound optical frequency shift device connects the input of the first semiconductor optical amplifier, the outfan of the first semiconductor optical amplifier is connected with another input of polarization-maintaining fiber coupler, forms the gain compensation type path mismatch torus with different polarization states switching under odd even time light recurrent state, another outfan of polarization-maintaining fiber coupler connects the input of the first polarizing beam splitter, one of them outfan of the first polarizing beam splitter is connected with the input of the first optical path delay line, another outfan is connected with one of them input of the second polarizing beam splitter, the outfan of the first optical path delay line is connected with another input of the second polarizing beam splitter, and the outfan of the second polarizing beam splitter connects the input of the belt device of polarization maintaining optical fibre, the first outfan of the belt device of polarization maintaining optical fibre connects the input of the 3rd polarizing beam splitter, and two outfans of the 3rd polarizing beam splitter connect respectively the first optical fiber collimator and the second optical fiber collimator, the second outfan of the belt device of polarization maintaining optical fibre connects the input of the second fiber adapter, and the outfan of the second fiber adapter connects one of them input of the 4th single-mode optical-fibre coupler, one of them outfan of the 3rd single-mode optical-fibre coupler connects the input of rising tone optical frequency shift device, the outfan of rising tone optical frequency shift device connects the input of the second semiconductor optical amplifier, the outfan of the second semiconductor optical amplifier connects the input of the second Polarization Controller, the outfan of the second Polarization Controller connects the input of the second optical path delay line, the outfan of the second optical path delay line is connected with another input of the 3rd single-mode optical-fibre coupler, form reference arm gain compensation type path mismatch torus, another outfan of the 3rd single-mode optical-fibre coupler connects the input of single-mode fiber circulator, the first outfan of single-mode fiber circulator connects the input of the 3rd optical fiber collimator, the second outfan of single-mode fiber circulator connects the input of the 3rd Polarization Controller, the outfan of the 3rd Polarization Controller connects another input of the 4th single-mode optical-fibre coupler, two outfans of the 4th single-mode optical-fibre coupler connect respectively two inputs of high bandwidth balance photodetector, and the circuit output end of this high bandwidth balance photodetector is connected with another input signal channel of high-speed data acquisition card, the outfan of high-speed data acquisition card is connected with computer, the triggering signal outfan of swept light source is connected with high-speed data acquisition card triggering signal input,

after the low-coherent light that swept light source is sent enters the first single-mode optical-fibre coupler, part light enters Mach-Zehnder interferometer and demarcates unit, another part light is divided into two-way by the second single-mode optical-fibre coupler, wherein a road light enters polarization-maintaining fiber coupler after by the first Polarization Controller and the first fiber adapter, and another road light enters the 3rd single-mode optical-fibre coupler, the light that enters polarization-maintaining fiber coupler separates a part of light and enters the first polarizing beam splitter, light by the first polarizing beam splitter is divided into two-way, the first optical path delay line of leading up to enters the second polarizing beam splitter, another road directly enters the second polarizing beam splitter, enter the input of the belt device of polarization maintaining optical fibre from the light of the second polarizing beam splitter outgoing, the light that enters the belt device of polarization maintaining optical fibre enters the input of the 3rd polarizing beam splitter by the first outfan, enter respectively the input of the first optical fiber collimator and the second optical fiber collimator from the light of the 3rd polarizing beam splitter outgoing, inject full eye to be measured from the light of the first optical fiber collimator outgoing after by polarization splitting prism, scanning galvanometer and first lens, inject full eye to be measured from the light of the second optical fiber collimator outgoing after by corner cube prism, the first reflecting mirror, the second lens, polarization splitting prism, scanning galvanometer and first lens, the light that reflects from the 3rd polarizing beam splitter is again by polarization maintaining optical fibre go in ring the first outfan of device, the second outfan of the belt device of polarization maintaining optical fibre and one of them input that the second fiber adapter is injected the 4th single-mode optical-fibre coupler, enter for the second time polarization-maintaining fiber coupler from another part light of polarization-maintaining fiber coupler output after by polarization state switch, first sound optical frequency shift device and the first semiconductor optical amplifier, the light that enters for the second time polarization-maintaining fiber coupler is divided into two parts equally, arrive the 4th single-mode optical-fibre coupler and enter for the third time polarization-maintaining fiber coupler along above-mentioned path respectively, by that analogy, the light that enters polarization-maintaining fiber coupler for the N-1 time also arrives the 4th single-mode optical-fibre coupler and enters polarization-maintaining fiber coupler the N time along above-mentioned path, the same light that enters the 3rd single-mode optical-fibre coupler also separates a part of light and enters the input of single-mode fiber circulator, after entering the 3rd optical fiber collimator by the first outfan, the light that enters the single-mode fiber circulator injects the 3rd lens and the second reflecting mirror, the light that reflects, successively after the first outfan, the second outfan and the 3rd Polarization Controller of single-mode fiber circulator, enters the 4th single-mode optical-fibre coupler, pass through rising tone optical frequency shift device from another part light of the 3rd single-mode optical-fibre coupler output, the second semiconductor optical amplifier, enter for the second time the 3rd single-mode optical-fibre coupler after the second Polarization Controller and the second optical path delay line, the light that enters for the second time the 3rd single-mode optical-fibre coupler is divided into two parts equally, arrive the 4th single-mode optical-fibre coupler and enter for the third time the 3rd single-mode optical-fibre coupler along above-mentioned path respectively, by that analogy, the light that N-1 enters the 3rd single-mode optical-fibre coupler also arrives the 4th single-mode optical-fibre coupler and enters the 3rd single-mode optical-fibre coupler for the N time along above-mentioned path, above-mentioned all light that enter the 4th single-mode optical-fibre coupler interfere, interference signal is surveyed through high bandwidth balance photodetector, the measured interference signal in two-way unit is by the high-speed data acquisition card synchronous acquisition, the signal that collects is transferred in the internal memory of computer and carries out date processing, and the outfan of high-speed data acquisition card is connected with computer.

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