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CN104483289B - Birefringence detection device and birefringence detection method based on sweep frequency optical coherence tomography technology - Google Patents

Birefringence detection device and birefringence detection method based on sweep frequency optical coherence tomography technology Download PDF

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CN104483289B
CN104483289B CN201410775281.8A CN201410775281A CN104483289B CN 104483289 B CN104483289 B CN 104483289B CN 201410775281 A CN201410775281 A CN 201410775281A CN 104483289 B CN104483289 B CN 104483289B
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陈翰
胡才雨
孙小菡
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Southeast University
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Abstract

本发明公开了一种基于扫频光学相干层析技术的双折射率检测装置及其方法。包括扫频激光器、光调制器、掺铒光纤放大器、耦合器、第一光纤、第二光纤、偏振复用合波器,半导体光放大器、环路器、偏振控制器、光探测器、微波信号滤波器、微波信号放大器、微波信号分路器、示波器和汇聚透镜。本发明着眼于新型光电子技术,尤其是微波光子学的发展与创新对光学相干层析的结构设计改变,提出一种基于双环光电振荡器的扫频偏振光学相干层析双折射率检测技术,实现了对生物组织的双折射率变化的检测转变为对微波信号频率的测量。同时本发明使用了半导体光放大器,利用其双折射效应来补偿光电混合环形结构谐振腔长度变化,实现了应力、温度可校准的检测。

The invention discloses a double refraction index detection device and method based on frequency-sweeping optical coherence tomography technology. Including swept frequency laser, optical modulator, erbium-doped fiber amplifier, coupler, first optical fiber, second optical fiber, polarization multiplexer, semiconductor optical amplifier, circulator, polarization controller, optical detector, microwave signal Filters, microwave signal amplifiers, microwave signal splitters, oscilloscopes and converging lenses. The present invention focuses on the new optoelectronic technology, especially the development and innovation of microwave photonics to change the structural design of optical coherence tomography, and proposes a double-ring photoelectric oscillator-based scanning polarization optical coherence tomography birefringence detection technology to realize The detection of birefringence changes in biological tissues is transformed into the measurement of microwave signal frequency. Simultaneously, the invention uses a semiconductor optical amplifier, uses its birefringence effect to compensate the length change of the resonant cavity of the photoelectric hybrid ring structure, and realizes the calibrated detection of stress and temperature.

Description

基于扫频光学相干层析技术的双折射率检测装置及其方法Birefringence detection device and method based on swept frequency optical coherence tomography

技术领域technical field

本发明涉及的是一种基于扫频偏振光学相干层析技术的双折射率检测装置及检测方法。The invention relates to a birefringence detection device and detection method based on frequency-sweeping polarization optical coherence tomography technology.

背景技术Background technique

随着人们对于生活质量要求的不断提高,在医疗检测中对无损伤、安全无害的检测方式的需求也就越来越强烈,一些传统医学影像方法在成像时需要添加专门的显影剂等帮助成像的物质或者借助X射线等辐射源,这些外界因素的加入或多或少会对人体造成伤害。而OCT(偏振光学相干层析,optical coherence tomography,文中简称OCT)技术利用光作为成像手段,通过干涉的方法获取生物组织背向散射光,对组织成像并获得组织内部信息,如双折射信息、组织的光谱信息、血液多普勒信息等;只需借助光这个媒介,无需添加任何外加的显影剂,不需要进行生理切片等创伤手段进行探测,属无损检测,因而较其它影像技术更为安全,被称为“光学活检”。目前,OCT已发展出四个分支,包括:时域OCT、傅里叶域OCT、平行光束OCT和功能OCT。With the continuous improvement of people's requirements for the quality of life, the demand for non-invasive, safe and harmless detection methods in medical detection is becoming more and more intense. Some traditional medical imaging methods need to add special developer and other assistance during imaging. Imaging substances or radiation sources such as X-rays, the addition of these external factors will more or less cause harm to the human body. OCT (optical coherence tomography, optical coherence tomography, referred to as OCT in the text) technology uses light as an imaging method to obtain backscattered light from biological tissue through interference, image the tissue and obtain internal information of the tissue, such as birefringence information, Spectral information of tissues, blood Doppler information, etc.; it only needs to use the medium of light, without adding any additional contrast agent, and does not need to perform traumatic means such as physiological slices for detection. It is a non-destructive test, so it is safer than other imaging technologies , known as an "optical biopsy". At present, OCT has developed four branches, including: time domain OCT, Fourier domain OCT, parallel beam OCT and functional OCT.

时域OCT,时域OCT是OCT家族中发展最早的形式,OCT的其它分支都是由其演变而成的;傅里叶域OCT:傅里叶域OCT在时域OCT的基础上取消了纵向扫描,而在光接收端,使用光谱仪代替光电探测器;在傅里叶域OCT中,干涉图是以光学频率函数的形式进行探测的。通过参考臂中一个固定的光学延迟,样品中不同深度反射回的光会产生与不同频率分量产生干涉图样。再通过傅里叶变换就可以解出不同深度的反射情况,这样一来就可以产生样品的一个深度分布(A-扫描)。根据光源和探测类型的不同,傅里叶域OCT可以分为:谱域OCT和扫频OCT。平行光束OCT,与其它OCT不同,照在平行光束OCT干涉仪两臂的不是光点而是平行光束;相应地在光接收端使用了一组而不是一个光电探测器,这使得它可以取消横向扫描,只利用纵向扫描形成二维图像,缩短了成像时间;功能OCT:功能OCT不仅可以采集普通OCT所关注的组织反射率信息,形成灰度图像,对其它由于病变引起的组织特性变化也十分敏感,对这些附加信息的提取能够为医学诊断提供更多的依据,提高诊断效率。按照所提取的组织特性不同,功能OCT可分为多普勒OCT和偏振OCT。Time-domain OCT, time-domain OCT is the earliest form in the OCT family, and other branches of OCT are evolved from it; Fourier-domain OCT: Fourier-domain OCT cancels the longitudinal direction on the basis of time-domain OCT scanning, while at the light-receiving end, a spectrometer is used instead of a photodetector; in Fourier-domain OCT, the interferogram is detected as a function of optical frequency. With a fixed optical delay in the reference arm, light reflected back at different depths in the sample produces an interference pattern with different frequency components. Then the reflection at different depths can be solved by Fourier transform, so that a depth distribution (A-scan) of the sample can be generated. According to different light sources and detection types, Fourier domain OCT can be divided into: spectral domain OCT and frequency sweep OCT. Parallel-beam OCT, unlike other OCT, what shines on the two arms of the parallel-beam OCT interferometer is not a light spot but a parallel beam; correspondingly, a group of photodetectors is used instead of a photodetector at the light-receiving end, which makes it possible to cancel the lateral Scanning only uses longitudinal scanning to form a two-dimensional image, which shortens the imaging time; functional OCT: functional OCT can not only collect the tissue reflectance information that ordinary OCT focuses on, and form a grayscale image, it is also very sensitive to other changes in tissue characteristics caused by lesions. Sensitive, the extraction of these additional information can provide more basis for medical diagnosis and improve diagnostic efficiency. According to the extracted tissue characteristics, functional OCT can be divided into Doppler OCT and polarization OCT.

本发明所提出基于扫频偏振光学相干层析技术的双折射率检测方法及装置,核心技术是采用微波光子学领域的新型光电振荡方式产生微波信号的方法,将对生物组织的双折射率变化的检测转变为对微波信号频率的测量,其检测方法及装置结构不同于目前OCT检测方法。1982年,Neyer和Voges首次提出了利用输出端的光信号反馈控制电光调制器的这种环形结构来实现振荡器的光电振荡器原理和结构。1994年,美国喷气动力实验室的X.Steve.Yao和Lute Maleki等人提出并演示了第一个光电振荡器结构,产生了高质量的微波信号。2000年,Yao和Maleki提出通过增加光纤环路(长光纤和短光纤)形成一个光滤波器的双环路光电振荡器结构来降低相位噪声。本发明所提出的检测方法及装置采用偏振复用型双环光电振荡器方案,利用其产生的低相位噪声、稳定、频谱干净的微波信号,把被测生物组织作为谐振腔的一部分加入到光纤反馈回路中形成振荡,将对生物组织的双折射率变化的检测转变为对微波信号频率的测量,利用基频的N次谐波进行测量。偏振OCT可以得到普通OCT所忽略的组织双折射信息,健康的生物组织具有规律的双折射分布,而病变的生物组织,其双折射分布遭到破坏,甚至完全丧失双折射性质。在本发明实施例装置中被测生物组织的双折射率变化越显著,输出微波的频率间隔越小,而利用振荡基频的N次谐波测量,比传统偏振OCT检测方法测量范围更广,测量精度更高,这使其在医学领域有着很好的应用前景。The birefringence detection method and device based on the frequency-sweeping polarization optical coherence tomography proposed by the present invention, the core technology is a method of generating microwave signals using a new photoelectric oscillation method in the field of microwave photonics, which will change the birefringence of biological tissues The detection is transformed into the measurement of microwave signal frequency, and its detection method and device structure are different from the current OCT detection method. In 1982, Neyer and Voges proposed for the first time the principle and structure of an optoelectronic oscillator that uses the optical signal feedback at the output to control the ring structure of the electro-optic modulator to realize the oscillator. In 1994, X.Steve.Yao and Lute Maleki of the Jet Propulsion Laboratory of the United States proposed and demonstrated the first photoelectric oscillator structure, which produced high-quality microwave signals. In 2000, Yao and Maleki proposed to reduce phase noise by adding fiber loops (long fiber and short fiber) to form a dual-loop OEO structure of an optical filter. The detection method and device proposed by the present invention adopt the scheme of polarization multiplexing double-loop photoelectric oscillator, and use the microwave signal with low phase noise, stability and clean frequency spectrum generated by it to add the measured biological tissue as a part of the resonant cavity to the optical fiber feedback Oscillation is formed in the circuit, and the detection of the birefringence index change of the biological tissue is transformed into the measurement of the frequency of the microwave signal, and the Nth harmonic of the fundamental frequency is used for measurement. Polarized OCT can obtain tissue birefringence information that is ignored by ordinary OCT. Healthy biological tissues have regular birefringence distribution, while diseased biological tissues have their birefringence distribution destroyed or even completely lose their birefringence properties. In the device of the embodiment of the present invention, the more significant the change of the birefringence index of the measured biological tissue is, the smaller the frequency interval of the output microwave is, and the measurement range of the Nth harmonic of the fundamental frequency of oscillation is wider than that of the traditional polarization OCT detection method. The measurement accuracy is higher, which makes it have a good application prospect in the medical field.

本发明所提出基于扫频偏振光学相干层析技术的双折射率检测方法及装置,考虑到了在实际测量过程中,光电振荡器中光纤的传输特性参数容易受到环境因素的干扰而发生变化的现象。从传输损耗、带宽以及抗电磁干扰特性方面看,光纤是传送微波信号的理想介质,然而环境温度、压力以及弯曲均会导致光纤折射率变化,积累的传输延迟变化将直接导致微波信号的相位噪声和相位漂移。实验研究表明,光纤折射率随温度的变化率约为40ps/(km×℃),对于长度为100m的光纤,温度变化1℃相应的延迟约为4ps。压力对光纤传输相位的影响更为明显,实验研究表明,光纤折射率随压强的变化率约为70ps/(km×MPa),对于长度为100m的光纤,压强变化1MPa相应的延迟约为7ps。考虑到短时间内环境参数不会发生突变,因此相位延迟漂移影响着测量结果长期稳定性及重复性,其引起的误差大小随着测量时间增长、应力、温度变化的增大而增大。因此如何针对偏振OCT方案中电路及光路的特点,设计相应的相位漂移补偿及抑制技术,从而进一步提高偏振OCT技术的检测精度是目前在OCT应用中亟需解决的问题。The birefringence detection method and device based on frequency-swept polarization optical coherence tomography proposed by the present invention take into account the phenomenon that the transmission characteristic parameters of the optical fiber in the photoelectric oscillator are easily disturbed by environmental factors and change during the actual measurement process . In terms of transmission loss, bandwidth, and anti-electromagnetic interference characteristics, optical fiber is an ideal medium for transmitting microwave signals. However, ambient temperature, pressure, and bending will cause changes in the refractive index of optical fibers, and the accumulated transmission delay changes will directly lead to phase noise of microwave signals. and phase shift. Experimental studies have shown that the rate of change of optical fiber refractive index with temperature is about 40 ps/(km×°C). For an optical fiber with a length of 100 m, the delay corresponding to a temperature change of 1°C is about 4 ps. The influence of pressure on the optical fiber transmission phase is more obvious. Experimental studies have shown that the rate of change of optical fiber refractive index with pressure is about 70ps/(km×MPa). For an optical fiber with a length of 100m, the delay corresponding to a pressure change of 1MPa is about 7ps. Considering that the environmental parameters will not change suddenly in a short period of time, the phase delay drift affects the long-term stability and repeatability of the measurement results, and the error caused by it increases with the increase of measurement time, stress and temperature changes. Therefore, how to design the corresponding phase drift compensation and suppression technology according to the characteristics of the circuit and optical path in the polarization OCT scheme, so as to further improve the detection accuracy of the polarization OCT technology is an urgent problem to be solved in the current OCT application.

发明内容Contents of the invention

技术问题:本发明所要解决的技术问题是:提供一种基于扫频偏振光学相干层析技术的双折射率检测装置,可对应力和温度进行校准,降低应力和温度变化对检测精度带来的影响;同时还提供该检测装置的检测方法,将对生物组织的双折射率变化的检测转变为对微波信号频率进行测量。Technical problem: The technical problem to be solved by the present invention is to provide a birefringence detection device based on frequency-swept polarization optical coherence tomography, which can calibrate stress and temperature, and reduce the impact of stress and temperature changes on detection accuracy. Influence; at the same time, the detection method of the detection device is also provided, which converts the detection of the birefringence index change of the biological tissue into the measurement of the frequency of the microwave signal.

技术方案:为解决上述技术问题,本发明采用的技术方案是:Technical scheme: in order to solve the above technical problems, the technical scheme adopted in the present invention is:

一种基于扫频偏振光学相干层析双折射率的检测装置,该检测装置包括扫频激光器、光调制器、掺铒光纤放大器、耦合器、第一光纤、第二光纤、偏振复用合波器,半导体光放大器、环路器、偏振控制器、光探测器、微波信号滤波器、微波信号放大器、微波信号分路器、示波器和汇聚透镜;扫频激光器的输出端与光调制器的输入端连接,光调制器的输出端与掺铒光纤放大器的输入端连接,掺铒光纤放大器的输出端与耦合器的输入端连接,耦合器的输出端分别通过第一光纤和第二光纤与偏振复用合波器的输入端连接,进一步,所述的第一光纤和第二光纤的长度不相等。偏振复用合波器的输出端与半导体光放大器的输入端连接,半导体光放大器的输出端与环路器的第一端口连接,环路器的第二端口通过透镜将光聚焦到生物样品上,并且通过透镜将反射光送回环路器的第二端口,环路器的第三端口与偏振控制器的输入端连接,偏振控制器的输出端与光探测器的输入端连接,光探测器的输出端与微波信号滤波器的输入端连接,微波信号滤波器的输出端与微波信号放大器的输入端连接,微波信号放大器的输出端与分路器的输入端连接,分路器的第一输出端口与示波器的输入端连接,分路器的第二输出端口与光调制器的微波调制端连接。A detection device based on frequency-sweeping polarization optical coherence tomography birefringence, the detection device includes a frequency-sweeping laser, an optical modulator, an erbium-doped fiber amplifier, a coupler, a first optical fiber, a second optical fiber, and a polarization multiplexer Semiconductor optical amplifiers, circulators, polarization controllers, optical detectors, microwave signal filters, microwave signal amplifiers, microwave signal splitters, oscilloscopes and converging lenses; the output of the swept laser and the input of the optical modulator The output end of the optical modulator is connected to the input end of the erbium-doped fiber amplifier, the output end of the erbium-doped fiber amplifier is connected to the input end of the coupler, and the output end of the coupler is respectively connected to the polarized fiber through the first optical fiber and the second optical fiber. The input end of the multiplexer is connected, further, the lengths of the first optical fiber and the second optical fiber are not equal. The output end of the polarization multiplexer is connected to the input end of the semiconductor optical amplifier, the output end of the semiconductor optical amplifier is connected to the first port of the circulator, and the second port of the circulator focuses the light onto the biological sample through the lens , and send the reflected light back to the second port of the circulator through the lens, the third port of the circulator is connected to the input terminal of the polarization controller, the output terminal of the polarization controller is connected to the input terminal of the photodetector, and the photodetector The output end of the microwave signal filter is connected with the input end of the microwave signal filter, the output end of the microwave signal filter is connected with the input end of the microwave signal amplifier, the output end of the microwave signal amplifier is connected with the input end of the splitter, and the first splitter One output port is connected with the input end of the oscilloscope, and the second output port of the splitter is connected with the microwave modulation end of the optical modulator.

一种上述的基于扫频偏振光学相干层析技术的双折射率检测方法,该检测方法包括以下过程:利用扫频激光器发出连续的光波,光波经光调制器调制和掺铒光纤放大器放大后,通过耦合器耦合进入第一光纤和第二光纤中,偏振复用合波器将第一光纤和第二光纤输出的调制光信号分成偏振态相互正交的两束信号,两束信号分别对准半导体光放大器的横电模和横磁模,通过控制半导体光放大器的偏置电流,获得补偿后的垂直偏振光调制信号,利用环路器将补偿后的垂直偏振光调制信号穿过透镜射向生物组织样品,然后该垂直偏振光调制信号由生物组织样品反射,形成携带生物组织信息的反射光,反射光穿过透镜,返回环路器中,由环路器的第三端口传至偏振控制器中,偏振控制器控制反射光的传输偏振态,经光探测器输出微波信号,微波信号经微波信号滤波器滤波后,由微波信号放大器放大,通过分路器分路为两路,一路反馈至光调制器中,形成闭环光电振荡回路,另一路输出至示波器中,测量微波信号的频率。A kind of above-mentioned birefringence detection method based on frequency-sweeping polarization optical coherence tomography technology, this detection method comprises the following process: Utilize frequency-sweeping laser to send continuous light wave, after light wave is modulated by light modulator and erbium-doped fiber amplifier amplifies, Coupled into the first optical fiber and the second optical fiber through the coupler, the polarization multiplexer divides the modulated optical signal output by the first optical fiber and the second optical fiber into two signals whose polarization states are orthogonal to each other, and the two signals are respectively aligned The transverse electric mode and transverse magnetic mode of the semiconductor optical amplifier, by controlling the bias current of the semiconductor optical amplifier, obtain the compensated vertically polarized light modulation signal, and use the circulator to send the compensated vertically polarized light modulation signal through the lens to the Biological tissue sample, then the vertically polarized light modulation signal is reflected by the biological tissue sample to form reflected light carrying biological tissue information, the reflected light passes through the lens, returns to the circulator, and is transmitted to the polarization control by the third port of the circulator In the device, the polarization controller controls the transmission polarization state of the reflected light, and the microwave signal is output by the optical detector. After the microwave signal is filtered by the microwave signal filter, it is amplified by the microwave signal amplifier. To the optical modulator to form a closed-loop photoelectric oscillation circuit, and the other output to the oscilloscope to measure the frequency of the microwave signal.

进一步,所述的基于扫频偏振光学相干层析技术的双折射率检测装置,第一光纤和第二光纤的长度不相等。Further, in the described birefringence detection device based on frequency-swept polarization optical coherence tomography, the lengths of the first optical fiber and the second optical fiber are not equal.

进一步,所述的基于扫频偏振光学相干层析技术的双折射率检测装置的检测方法,第一光纤和第二光纤所输出的调制光信号由偏振复用合波器生成垂直偏振的调制光信号,两个垂直偏振方向分别对准半导体光放大器的横电模和横磁模方向。半导体光放大器是一种对外来光子产生受激辐射放大的光电子器件,其本质是一种处于粒子数反转条件下的半导体增益介质。通过控制半导体光放大器的偏置电流,控制其双折射效应,以补偿受应力、温度影响而使光电混合环形结构谐振腔长度发生的变化,实现校准检测。Further, in the detection method of the birefringence detection device based on frequency-swept polarization optical coherence tomography, the modulated light signals output by the first optical fiber and the second optical fiber are used to generate vertically polarized modulated light by a polarization multiplexer Signal, the two vertical polarization directions are respectively aligned with the transverse electric mode and transverse magnetic mode directions of the semiconductor optical amplifier. A semiconductor optical amplifier is an optoelectronic device that generates stimulated radiation amplification for external photons, and its essence is a semiconductor gain medium under the condition of particle population inversion. By controlling the bias current of the semiconductor optical amplifier and controlling its birefringence effect, the change of the length of the resonant cavity of the photoelectric hybrid ring structure is compensated by the influence of stress and temperature, and the calibration detection is realized.

进一步,所述的基于扫频偏振光学相干层析技术的双折射率检测装置的检测方法,所经过半导体光放大器实现应力、温度补偿后的垂直偏振光调制信号,经过环路器穿过汇聚透镜射向生物组织样品,反射光受生物组织样品的背向散射率和双折射率共同影响,使得光电混合的环形结构谐振腔参数发生改变,进而改变了其振荡产生的微波信号的频率,从而实现了对生物组织的双折射率变化的检测转变为在示波器中测量微波信号的频率。Further, in the detection method of the birefringence detection device based on frequency-sweeping polarization optical coherence tomography technology, the vertically polarized light modulation signal after the semiconductor optical amplifier realizes stress and temperature compensation passes through the circulator and passes through the converging lens The reflected light is affected by the backscattering rate and birefringence of the biological tissue sample, which changes the parameters of the optical-electrical hybrid ring structure resonator, and then changes the frequency of the microwave signal generated by its oscillation, thus realizing The detection of birefringence changes in biological tissue was transformed into measuring the frequency of microwave signals in an oscilloscope.

有益效果:与现有技术相比,本发明具有以下有益效果:Beneficial effects: compared with the prior art, the present invention has the following beneficial effects:

(1)本发明所提出基于扫频偏振光学相干层析技术的双折射率检测方法及装置,实现了对生物组织的双折射率变化的检测转变为对微波信号频率的测量,核心技术是采用微波光子学领域的新型光电振荡方式产生微波信号的方法,检测方法及装置结构不同于目前OCT已发展出四个分支,包括:时域OCT、傅里叶域OCT、平行光束OCT和功能OCT。(1) The birefringence detection method and device based on swept frequency polarization optical coherence tomography proposed by the present invention realizes the transformation of the detection of birefringence changes in biological tissues into the measurement of microwave signal frequency. The core technology is to use The new photoelectric oscillation method in the field of microwave photonics produces microwave signals. The detection method and device structure are different from the current OCT. Four branches have been developed, including: time domain OCT, Fourier domain OCT, parallel beam OCT and functional OCT.

(2)本发明所提出基于扫频偏振光学相干层析技术的双折射率检测方法及装置,采用偏振复用型双环光电振荡器方案。在这种双环结构的光电振荡器中,振荡器起振的振荡模式间隔由短光纤环路决定,相位噪声则由长光纤环路决定,双环振荡器可以得到模式间隔大且相位噪声低的振荡信号。利用其产生的低相位噪声、稳定、频谱干净的微波信号,把被测生物组织作为谐振腔的一部分加入到光纤反馈回路中形成振荡,将对生物组织的双折射率变化的检测转变为对微波信号频率的测量,利用基频的N次谐波进行测量。在本发明实施例装置中被测生物组织的双折射率变化越显著,输出微波的频率间隔越小,而利用振荡基频的N次谐波测量,比传统偏振OCT检测方法测量范围更广,测量精度更高,这使其在医学领域有着很好的应用前景。(2) The birefringence detection method and device based on frequency-swept polarization optical coherence tomography proposed by the present invention adopts a polarization multiplexing double-loop photoelectric oscillator scheme. In this kind of double-ring structure optoelectronic oscillator, the oscillation mode interval of the oscillator is determined by the short fiber loop, and the phase noise is determined by the long fiber loop. The double-ring oscillator can obtain oscillation with a large mode interval and low phase noise. Signal. Using the low-phase-noise, stable, and clean-spectrum microwave signals generated by it, the measured biological tissue is added to the optical fiber feedback loop as a part of the resonant cavity to form oscillations, and the detection of birefringence changes in biological tissue is converted to microwave The measurement of the signal frequency is carried out by using the Nth harmonic of the fundamental frequency. In the device of the embodiment of the present invention, the more significant the change of the birefringence index of the measured biological tissue is, the smaller the frequency interval of the output microwave is, and the measurement range of the Nth harmonic of the fundamental frequency of oscillation is wider than that of the traditional polarization OCT detection method. The measurement accuracy is higher, which makes it have a good application prospect in the medical field.

(3)本发明所提出基于扫频偏振光学相干层析技术的双折射率检测方法及装置,针对在OCT系统中普遍存在的环境因素影响,尤其是应力和温度变化对相关光路带来的精度下降现象,提出一种基于半导体光放大器的应力和温度可校准技术。光信号及电信号在传输介质中传播,其必然造成信号的相位延迟,当介质特性参数不变时,其传播延迟固定,因此可通过校正的方法将相位延迟消除。半导体光放大器是一种对外来光子产生受激辐射放大的光电子器件,其本质是一种处于粒子数反转条件下的半导体增益介质。利用其可控的双折射效应,来补偿双环光电振荡器的谐振腔长度变化,实现了其应力、温度可校准检测。(3) The birefringence detection method and device based on swept-frequency polarization optical coherence tomography proposed by the present invention is aimed at the influence of environmental factors that are ubiquitous in OCT systems, especially the accuracy brought by stress and temperature changes on the relevant optical path drop phenomenon, a stress and temperature calibratable technique based on semiconductor optical amplifiers is proposed. The propagation of optical and electrical signals in the transmission medium will inevitably cause the phase delay of the signal. When the characteristic parameters of the medium are constant, the propagation delay is fixed, so the phase delay can be eliminated by correction. A semiconductor optical amplifier is an optoelectronic device that generates stimulated radiation amplification for external photons, and its essence is a semiconductor gain medium under the condition of particle population inversion. The controllable birefringence effect is used to compensate the change of the resonant cavity length of the double-ring photoelectric oscillator, and the calibrated detection of its stress and temperature is realized.

附图说明Description of drawings

图1为本发明的结构示意图。图中有:扫频激光器1、光调制器2、掺铒光纤放大器3、耦合器4、第一光纤5、第二光纤6、偏振复用合波器7,半导体光放大器8、环路器9、第一端口901、第二端口902、第三端口903、偏振控制器10、光探测器11、微波信号滤波器12、微波信号放大器13、微波信号分路器14、第一输出端口1401、第二输出端口1402、示波器15、汇聚透镜16。Fig. 1 is a structural schematic diagram of the present invention. In the figure are: frequency-sweeping laser 1, optical modulator 2, erbium-doped fiber amplifier 3, coupler 4, first optical fiber 5, second optical fiber 6, polarization multiplexer 7, semiconductor optical amplifier 8, looper 9. First port 901, second port 902, third port 903, polarization controller 10, photodetector 11, microwave signal filter 12, microwave signal amplifier 13, microwave signal splitter 14, first output port 1401 , a second output port 1402 , an oscilloscope 15 , and a converging lens 16 .

图2为本发明实施例中,测量某一生物组织样品时装置输出的微波信号频谱图。Fig. 2 is a spectrum diagram of the microwave signal output by the device when measuring a certain biological tissue sample in an embodiment of the present invention.

图3为本发明实施例中,测量某一生物组织样品时装置输出的微波信号波形图与相位噪声图。Fig. 3 is a microwave signal waveform diagram and a phase noise diagram output by the device when measuring a certain biological tissue sample in an embodiment of the present invention.

图4为本发明实施例中,测量某一生物组织样品时应力、温度校准情况下装置输出的微波信号频率分布图与相位噪声分布图。Fig. 4 is a distribution diagram of frequency distribution and phase noise of microwave signals output by the device under the condition of stress and temperature calibration when measuring a certain biological tissue sample in an embodiment of the present invention.

具体实施方式detailed description

下面结合附图,对本发明的实施例作详细说明。本实施例在以本发明技术方案为前提下进行实施,给出了详细的实施方式和具体的操作过程,但本发明的保护范围不限于下述的实施例。Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. This embodiment is carried out on the premise of the technical solution of the present invention, and the detailed implementation and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

如图1所示,本发明的一种基于扫频偏振光学相干层析技术的双折射率检测装置,包括扫频激光器1、光调制器2、掺铒光纤放大器3、耦合器4、第一光纤5、第二光纤6、偏振复用合波器7,半导体光放大器8、环路器9、偏振控制器10、光探测器11、微波信号滤波器12、微波信号放大器13、微波信号分路器14、示波器15和汇聚透镜16。扫频激光器1的输出端与光调制器2的输入端连接,光调制器2的输出端与掺铒光纤放大器3的输入端连接,掺铒光纤放大器3的输出端与耦合器4的输入端连接,耦合器4的输出端分别通过第一光纤5和第二光纤6与偏振复用合波器7的输入端连接,偏振复用合波器7的输出端与半导体光放大器8的输入端连接,半导体光放大器8的输出端与环路器9的第一端口901连接,环路器9的第二端口902通过汇聚透镜16将光聚焦到生物样品上,并且通过透镜16将反射光送回环路器9的第二端口902,环路器9的第三端口903与偏振控制器10的输入端连接,偏振控制器10的输出端与光探测器11的输入端连接,光探测器11的输出端与微波信号滤波器12的输入端连接,微波信号滤波器12的输出端与微波信号放大器13的输入端连接,微波信号放大器13的输出端与微波信号分路器14的输入端连接,微波信号分路器14的第一输出端口1401与示波器15的输入端连接,微波信号分路器14的第二输出端口1402与光调制器2的微波调制端连接。As shown in Figure 1, a kind of birefringence detection device based on frequency-sweeping polarization optical coherence tomography of the present invention comprises frequency-sweeping laser 1, light modulator 2, erbium-doped fiber amplifier 3, coupler 4, first Optical fiber 5, second optical fiber 6, polarization multiplexer 7, semiconductor optical amplifier 8, looper 9, polarization controller 10, optical detector 11, microwave signal filter 12, microwave signal amplifier 13, microwave signal splitter Router 14, oscilloscope 15 and converging lens 16. The output end of frequency-sweeping laser 1 is connected with the input end of optical modulator 2, and the output end of optical modulator 2 is connected with the input end of erbium-doped fiber amplifier 3, and the output end of erbium-doped fiber amplifier 3 is connected with the input end of coupler 4 Connect, the output end of the coupler 4 is connected with the input end of the polarization multiplexer 7 through the first optical fiber 5 and the second optical fiber 6 respectively, the output end of the polarization multiplexer 7 is connected with the input end of the semiconductor optical amplifier 8 connected, the output end of the semiconductor optical amplifier 8 is connected to the first port 901 of the circulator 9, the second port 902 of the circulator 9 focuses the light onto the biological sample through the converging lens 16, and sends the reflected light to the biological sample through the lens 16. Back to the second port 902 of the circulator 9, the third port 903 of the circulator 9 is connected to the input end of the polarization controller 10, the output end of the polarization controller 10 is connected to the input end of the photodetector 11, and the photodetector The output end of 11 is connected with the input end of microwave signal filter 12, and the output end of microwave signal filter 12 is connected with the input end of microwave signal amplifier 13, and the output end of microwave signal amplifier 13 is connected with the input end of microwave signal splitter 14 The first output port 1401 of the microwave signal splitter 14 is connected to the input end of the oscilloscope 15 , and the second output port 1402 of the microwave signal splitter 14 is connected to the microwave modulation end of the optical modulator 2 .

上述的基于扫频偏振光学相干层析技术的双折射率检测方法,包括以下过程:利用扫频激光器1发出连续的光波,光波经光调制器2调制和掺铒光纤放大器3放大后,通过耦合器4耦合进入第一光纤5和第二光纤6中,偏振复用合波器7将第一光纤5和第二光纤6输出的调制光信号分成偏振态相互正交的两束信号,两束信号分别对准半导体光放大器8的横电模和横磁模,通过控制半导体光放大器8的偏置电流,获得补偿后的垂直偏振光调制信号,利用环路器9将补偿后的垂直偏振光调制信号穿过汇聚透镜16射向生物组织样品,然后该垂直偏振光调制信号由生物组织样品反射,形成携带生物组织信息的反射光。反射光中携带了生物组织样品的背向散射率和双折射率。反射光穿过汇聚透镜16,返回环路器9中,由环路器9的第三端口903传至偏振控制器10中,偏振控制器10控制反射光的传输偏振态,经光探测器11输出微波信号,微波信号经微波信号滤波器12滤波后,由微波信号放大器13放大,通过微波信号分路器14分路为两路,一路1402反馈至光调制器2中,形成闭环光电振荡回路,另一路1401输出至示波器15中,测量微波信号的频率。The above-mentioned birefringence detection method based on frequency-sweeping polarization optical coherence tomography technology includes the following process: Utilize frequency-sweeping laser 1 to send continuous light waves, after light waves are modulated by light modulator 2 and amplified by erbium-doped fiber amplifier 3, through coupling The optical fiber 4 is coupled into the first optical fiber 5 and the second optical fiber 6, and the polarization multiplexer 7 divides the modulated optical signals output by the first optical fiber 5 and the second optical fiber 6 into two signals whose polarization states are orthogonal to each other. The signals are respectively aligned with the transverse electric mode and the transverse magnetic mode of the semiconductor optical amplifier 8, and the compensated vertically polarized light modulation signal is obtained by controlling the bias current of the semiconductor optical amplifier 8, and the compensated vertically polarized light is converted by the circulator 9 The modulated signal passes through the converging lens 16 to the biological tissue sample, and then the vertically polarized light modulated signal is reflected by the biological tissue sample to form reflected light carrying biological tissue information. The reflected light carries the backscattering rate and birefringence of the biological tissue sample. The reflected light passes through the converging lens 16, returns to the circulator 9, and is transmitted to the polarization controller 10 by the third port 903 of the circulator 9. The polarization controller 10 controls the transmission polarization state of the reflected light, and passes through the photodetector 11 Output microwave signal, the microwave signal is filtered by the microwave signal filter 12, amplified by the microwave signal amplifier 13, divided into two paths by the microwave signal splitter 14, and one path 1402 is fed back to the optical modulator 2 to form a closed-loop photoelectric oscillation circuit , the other channel 1401 is output to the oscilloscope 15 to measure the frequency of the microwave signal.

进一步,所述的第一光纤5和第二光纤6的长度不相等。在光电振荡器系统中,光纤环路的储能时间决定了振荡器的品质因子,因此振荡器的相位噪声受到光纤延迟线的长度即延迟时间的影响。虽然可以通过增加光纤长度来降低相位噪声,但实际上当振荡器产生的频率满足一定条件时,会产生不同阶数的起振模式。由此可见,随着光纤长度的增加,波模数量也会增加,波模之间的频率间隔就会变小。理论上可以用一个足够窄的滤波器去除不需要的模式,但由于高品质因子的微波滤波器目前难以实现,因此结果不甚理想,所以使用长光纤的光电振荡器会产生不需要的模式。通过增加光纤环路(第一光纤5和第二光纤6)形成一个光滤波器的双环路光电振荡器结构来降低相位噪声,在这种双环结构的光电振荡器中,振荡器起振的振荡模式间隔由短光纤环路决定,相位噪声则由长光纤环路决定,双环振荡器可以得到模式间隔大且相位噪声低的振荡信号。Further, the lengths of the first optical fiber 5 and the second optical fiber 6 are not equal. In the optoelectronic oscillator system, the energy storage time of the fiber loop determines the quality factor of the oscillator, so the phase noise of the oscillator is affected by the length of the fiber delay line, that is, the delay time. Although the phase noise can be reduced by increasing the fiber length, in fact, when the frequency generated by the oscillator meets certain conditions, different orders of oscillation modes will be generated. It can be seen that as the length of the fiber increases, the number of wave modes will also increase, and the frequency interval between the wave modes will become smaller. It is theoretically possible to use a sufficiently narrow filter to remove unwanted modes, but the results are not ideal because microwave filters with high quality factors are currently difficult to achieve, so the use of long optical fiber optical oscillators will generate unwanted modes. The phase noise is reduced by increasing the optical fiber loop (the first optical fiber 5 and the second optical fiber 6) to form a double-loop photoelectric oscillator structure of an optical filter. In the photoelectric oscillator of this double-ring structure, the oscillation of the oscillator starts The mode interval is determined by the short fiber loop, and the phase noise is determined by the long fiber loop. The double-loop oscillator can obtain an oscillation signal with a large mode interval and low phase noise.

进一步,所述的第一光纤5和第二光纤6的输出的调制光信号由偏振复用合波器7生成垂直偏振的调制光信号,两个垂直偏振方向分别对准半导体光放大器8的横电模和横磁模方向。较强的双折射效应使得半导体光放大器8表现出相当的偏振相关性,通过控制半导体光放大器8偏置电流的改变,其横电模和横磁模式下折射率差也发生改变,使得通过半导体光放大器8后的偏振垂直的光调制信号引入不同的时延,以补偿受应力、温度影响而使光电混合环形结构谐振腔长度发生的变化,保证所产生微波信号频率和相位的稳定性,实现校准检测。Further, the output modulated optical signals of the first optical fiber 5 and the second optical fiber 6 are generated by the polarization multiplexer 7 to generate vertically polarized modulated optical signals, and the two vertical polarization directions are respectively aligned with the transverse direction of the semiconductor optical amplifier 8. Electric and transverse magnetic mode directions. The strong birefringence effect makes the semiconductor optical amplifier 8 exhibit considerable polarization dependence. By controlling the change of the bias current of the semiconductor optical amplifier 8, the refractive index difference between the transverse electric mode and the transverse magnetic mode also changes, so that through the semiconductor optical amplifier 8 Different time delays are introduced into the vertically polarized optical modulation signal after the optical amplifier 8 to compensate for the change in the length of the resonant cavity of the photoelectric hybrid ring structure due to the influence of stress and temperature, so as to ensure the stability of the frequency and phase of the generated microwave signal and realize Calibration detection.

进一步,所述的经过半导体光放大器8实现应力、温度补偿后的垂直偏振光调制信号,经过环路器9穿过汇聚透镜16射向生物组织样品,反射光受生物组织样品的背向散射率和双折射率共同影响,使得光电混合的环形结构谐振腔参数发生改变,进而改变了其振荡产生的微波信号的频率,从而实现了对生物组织的双折射率变化的检测转变为在示波器15中测量微波信号的频率。Further, the vertically polarized light modulation signal after the semiconductor optical amplifier 8 realizes stress and temperature compensation is directed to the biological tissue sample through the circulator 9 through the converging lens 16, and the reflected light is affected by the backscattering rate of the biological tissue sample. Together with the birefringence index, the parameters of the optical-electrical hybrid ring structure resonator are changed, and then the frequency of the microwave signal generated by its oscillation is changed, so that the detection of the change of the birefringence index of biological tissue is transformed into an oscilloscope15 Measures the frequency of microwave signals.

本发明所提出的检测方法及装置中,在已知微波信号滤波器12中心频率的前提下,微波信号分路器1402端口输入至光调制器2端口的微波信号fOEO由频率模式竞争决定,取决于两段单模光纤分别在横电模和横磁模式下引入的延时,分别记为τTE和τTM,考虑开环状态有:In the detection method and device proposed by the present invention, under the premise that the center frequency of the microwave signal filter 12 is known, the microwave signal f OEO input from the port of the microwave signal splitter 1402 to the port of the optical modulator 2 is determined by frequency mode competition, Depends on the delays introduced by the two sections of single-mode fiber in the transverse electric mode and transverse magnetic mode respectively, denoted as τ TE and τ TM , considering the open-loop state:

式(1) Formula 1)

其中,k和m分别为正整数。输入的偏振垂直的光调制信号分别对准半导体光放大器8的横电模和横磁模式方向。较强的双折射效应使得半导体光放大器8表现出相当的偏振相关性。通过控制半导体光放大器8偏置电流的改变,其横电模和横磁模式下折射率差也发生改变,使得通过半导体光放大器8后的偏振垂直的光调制信号引入不同的时延τTE,SOA和τTM,SOA,用于补偿应力和温度变化的影响,保证所产生微波信号频率和相位的稳定性。fOEO可以进一步表示为:Wherein, k and m are positive integers respectively. The input vertically polarized optical modulation signals are respectively aligned with the transverse electric mode and transverse magnetic mode directions of the semiconductor optical amplifier 8 . The strong birefringence effect makes the semiconductor optical amplifier 8 exhibit considerable polarization dependence. By controlling the change of the bias current of the semiconductor optical amplifier 8, the refractive index difference between the transverse electric mode and the transverse magnetic mode also changes, so that the vertically polarized optical modulation signal passing through the semiconductor optical amplifier 8 introduces different time delays τ TE, SOA and τ TM,SOA are used to compensate the influence of stress and temperature changes, and ensure the stability of the frequency and phase of the generated microwave signal. f OEO can be further expressed as:

式(2) Formula (2)

其中,τ′TE表示经过补偿之后的横电模式的时延,τ′TE=τTETE,SOA;τ′TM表示经过补偿之后的横磁模式的时延,τ′TM=τTMTM,SOAAmong them, τ′ TE represents the time delay of the transverse electric mode after compensation, τ′ TETETE,SOA ; τ′ TM represents the time delay of the transverse magnetic mode after compensation, τ′ TMTMTM,SOA .

补偿后的垂直偏振光调制信号经生物组织样品背向散射,由环路器9返回,光信号中携带了生物组织样品的背向散射率和双折射率信息,所产生的横电模式下的延时变化τTE,sample和横磁模式下的延时变化τTM,sample,最终导致系统输出微波信号频率的变化。返回的光信号传输至偏振控制器10控制其传输偏振态,经光探测器输出微波信号,再经微波信号滤波器12滤波后由微波信号放大器13放大,之后通过分路器14分路,一路反馈至光调制器2形成闭环光电振荡回路,另一路输出至示波器15进行测量。The compensated vertically polarized light modulation signal is backscattered by the biological tissue sample and returned by the circulator 9. The optical signal carries the backscattering rate and birefringence information of the biological tissue sample, and the generated transverse electric mode The delay change τ TE,sample and the delay change τ TM,sample in the transverse magnetic mode will eventually lead to a change in the frequency of the microwave signal output by the system. The returned optical signal is transmitted to the polarization controller 10 to control its transmission polarization state, and the microwave signal is output by the optical detector, and then filtered by the microwave signal filter 12 and amplified by the microwave signal amplifier 13, and then split by the splitter 14, one way It is fed back to the optical modulator 2 to form a closed-loop photoelectric oscillation circuit, and the other output is sent to the oscilloscope 15 for measurement.

由此,在本发明所提出的偏振复用型双环结构中,环路总延时由三部分构成:第一光纤5和第二光纤6的长度差引入的延时、半导体光放大器8双折射率差引入的偏振延时,以及被测生物组织双折射率差引入的偏振延时。fOEO可以进一步表示为:Thus, in the polarization-multiplexing double-ring structure proposed by the present invention, the total delay of the loop is composed of three parts: the delay introduced by the length difference between the first optical fiber 5 and the second optical fiber 6, the birefringence of the semiconductor optical amplifier 8 The polarization delay introduced by the difference in the rate of polarization, and the polarization delay introduced by the birefringence difference of the measured biological tissue. f OEO can be further expressed as:

式(3) Formula (3)

其中,横电模式下时延(τ″TE=τ′TETE,sample)决定了输出微波信号fOEO的频率间隔,横磁模式下时延(τ″TM=τ′TMTM,sample)决定了输出微波信号fOEO的频率范围。在光探测器11输出端,通过对输出微波信号fOEO频率测量与分析,实现了对生物组织的双折射率变化的检测。光探测器11输出电信号表示为:Among them, the time delay (τ″ TE =τ′ TETE,sample ) in the transverse electric mode determines the frequency interval of the output microwave signal f OEO , and the time delay in the transverse magnetic mode (τ″ TM =τ′ TMTM , sample ) determines the frequency range of the output microwave signal f OEO . At the output end of the optical detector 11, by measuring and analyzing the frequency of the output microwave signal f OEO , the detection of the change of the birefringence index of the biological tissue is realized. The output electrical signal of photodetector 11 is expressed as:

式(4) Formula (4)

其中,gTE和gTM分别表示偏振复用的两个环路的复数增益,f是整个系统内部传输的微波信号频率,Vi表示回路第i次输出的微波信号的幅值,Vi-1表示回路第i-1次输出的微波信号的幅值。信号在反馈回路中循环,其输出信号Vout(2πf)瞬态表达式为:Among them, g TE and g TM represent the complex gain of the two loops of polarization multiplexing respectively, f is the frequency of the microwave signal transmitted inside the whole system, V i represents the amplitude of the microwave signal output by the loop for the ith time, V i- 1 represents the amplitude of the microwave signal output by the loop for the i-1th time. The signal circulates in the feedback loop, and the transient expression of its output signal V out (2πf) is:

式(5) Formula (5)

其中,V0是起振前微波信号的幅值。Among them, V 0 is the amplitude of the microwave signal before oscillation.

由此可推导出等效微波功率信号P(2πf)为:From this, the equivalent microwave power signal P(2πf) can be deduced as:

式(6) Formula (6)

其中,R表示回路的等效阻抗,表示横电模式下经过传输所引起的相位变化,表示横磁模式下经过传输所引起的相位变化,在满足一定振荡频率和微波功率条件后,光电振荡器起振,其中绝大部分频率的微波信号被逐渐抑制,最终输出功率最大的微波信号即光电振荡器谐振频率信号,满足P(2πfOEO)=max{P(2πf)}。在偏振OCT成像过程中,改变光源波长与强度进行纵向扫描,由生物组织样品层在组织中所处深度和双折射率的变化,可实现对不同深度生物组织样品信息的提取。光源波长与实际成像深度和系统分辨率有关。一般来说波长较短的OCT系统,具有更高的成像分辨率。但考虑到需要对较强光散射特性的样品成像时,如生物组织,工作波长较长的系统更有优势。在本发明中,选用中心波长1310或1550nm。较长的中心工作波长不会被散射影响,光能够穿透到样品更深处并返回探测器。同时,平移台搭载生物组织样品进行横向移动,二者共同作用,实现了对生物组织样品双折射率分布的二维扫描成像。Among them, R represents the equivalent impedance of the loop, Indicates the phase change caused by transmission in the transverse electric mode, Indicates the phase change caused by transmission in the transverse magnetic mode, After satisfying a certain oscillation frequency and microwave power conditions, the optoelectronic oscillator starts to oscillate, and the microwave signals of most frequencies are gradually suppressed, and finally the microwave signal with the largest output power is the resonant frequency signal of the optoelectronic oscillator, which satisfies P(2πf OEO ) =max{P(2πf)}. In the polarized OCT imaging process, the wavelength and intensity of the light source are changed for longitudinal scanning, and the information of biological tissue samples at different depths can be extracted from the changes in the depth and birefringence of the biological tissue sample layer in the tissue. The wavelength of the light source is related to the actual imaging depth and system resolution. Generally speaking, OCT systems with shorter wavelengths have higher imaging resolution. However, considering the need to image samples with strong light-scattering properties, such as biological tissue, a system with a longer operating wavelength is more advantageous. In the present invention, the center wavelength of 1310 or 1550 nm is selected. The longer central operating wavelength is not affected by scattering, allowing light to penetrate deeper into the sample and return to the detector. At the same time, the translation stage carries the biological tissue sample to move laterally, and the two work together to realize the two-dimensional scanning imaging of the birefringence distribution of the biological tissue sample.

本实施例中,扫频激光器采用Insight公司成熟的超宽带可调谐激光器作为光源,型号:SLE-101,中心波长1310nm或1550nm,扫频速率400KHz,扫频范围80nm。光调制器采用JDS Uniphase公司的10020416,工作范围是1530-1565nm。半导体光放大器采用INPHENIX公司的IPSAD1501/1504,工作范围是1510-1590nm。光探测器采用康冠公司的KG-PR-10G。微波信号滤波器使用Mini-Circuits公司的低通滤波器LFCN-113+,截止频率是11GHz。微波信号放大器采用JDSU公司的H301,工作范围是2.488-12.2GHz。In this embodiment, the frequency-sweeping laser adopts Insight's mature ultra-broadband tunable laser as the light source, model: SLE-101, center wavelength 1310nm or 1550nm, frequency-sweeping rate 400KHz, frequency-sweeping range 80nm. The optical modulator adopts 10020416 of JDS Uniphase Company, and the working range is 1530-1565nm. The semiconductor optical amplifier adopts IPSAD1501/1504 of INPHENIX Company, and the working range is 1510-1590nm. The light detector is KG-PR-10G from KTC. The microwave signal filter uses the low-pass filter LFCN-113+ of Mini-Circuits Company, and the cut-off frequency is 11GHz. The microwave signal amplifier adopts H301 of JDSU Company, and the working range is 2.488-12.2GHz.

在本实施例的装置测试中,半导体光放大器的入纤功率保持为0dBm,调谐其注入电流,对系统输出的微波信号进行了时域、频域测量。在SOA注入电流为175mA时,测得系统输出的微波信号频率为8.8GHz,频谱图如图2所示。横坐标表示微波信号频率,单位GHz,纵坐标表示微波信号功率,单位dBm。如图2附图显示边模抑制比为-68dB。数据分析表明,本发明提出的检测方法与装置,可以实现将对生物组织的双折射率变化的检测转变为对微波信号频率的测量。相应时域输出波形与相位噪声分析如图3所示。图3中,横坐标表示频率偏置,单位log Hz,即将原频率取完对数后作为横坐标,纵坐标表示单边带相位噪声,单位dBc/Hz。测试数据表明此时相位噪声小于-104dBc/Hz(@10KHz)。数据分析表明,本发明提出的检测方法与装置,可以输出相位噪声较小的微波信号,其相位稳定。以保证较高的检测分辨率。In the device test of this embodiment, the fiber input power of the semiconductor optical amplifier is kept at 0 dBm, its injection current is tuned, and the microwave signal output by the system is measured in the time domain and frequency domain. When the SOA injection current is 175mA, the measured frequency of the microwave signal output by the system is 8.8GHz, and the frequency spectrum is shown in Figure 2. The abscissa indicates the frequency of the microwave signal in GHz, and the ordinate indicates the power of the microwave signal in dBm. Figure 2 shows that the side mode suppression ratio is -68dB. Data analysis shows that the detection method and device proposed by the present invention can convert the detection of the birefringence change of biological tissue into the measurement of microwave signal frequency. The corresponding time-domain output waveform and phase noise analysis are shown in Figure 3. In Figure 3, the abscissa represents the frequency offset, and the unit is log Hz, that is, the logarithm of the original frequency is taken as the abscissa, and the ordinate represents the SSB phase noise, and the unit is dBc/Hz. The test data shows that the phase noise is less than -104dBc/Hz (@10KHz). Data analysis shows that the detection method and device proposed by the present invention can output a microwave signal with less phase noise, and its phase is stable. To ensure a higher detection resolution.

逐步增加半导体光放大器注入电流从175mA到350mA,如图4所示。图4中,横坐标表示注入电流,单位mA,纵坐标表示振荡频率,单位GHz。带有方框的曲线为微波信号频率随注入电流的变化及其拟合曲线,带有圆圈的曲线为相位噪声随注入电流的变化及其拟合曲线。图4中,测量系统输出的微波信号频率从8.8GHz变化到8.65GHz,频率范围约为150MHz,其调谐步长约15MHz,整体相位噪声水平低于-100dBc/Hz(@10KHz)。数据分析表明,本发明提出的检测方法与装置,可以通过调谐半导体光放大器注入电流,以补偿受应力、温度影响而使光电混合环形结构谐振腔长度发生的变化,保证装置所产生微波信号频率和相位的稳定性,实现本发明实施例装置的可校准检测。Gradually increase the injection current of the semiconductor optical amplifier from 175mA to 350mA, as shown in Figure 4. In FIG. 4 , the abscissa represents the injection current in mA, and the ordinate represents the oscillation frequency in GHz. The curve with a box is the change of the microwave signal frequency with the injection current and its fitting curve, and the curve with a circle is the change of the phase noise with the injection current and its fitting curve. In Figure 4, the frequency of the microwave signal output by the measurement system changes from 8.8GHz to 8.65GHz, the frequency range is about 150MHz, the tuning step is about 15MHz, and the overall phase noise level is lower than -100dBc/Hz (@10KHz). Data analysis shows that the detection method and device proposed by the present invention can compensate the change in the length of the resonant cavity of the photoelectric hybrid ring structure due to the influence of stress and temperature by tuning the injection current of the semiconductor optical amplifier, so as to ensure the frequency and frequency of the microwave signal generated by the device. The stability of the phase realizes the calibratable detection of the device of the embodiment of the present invention.

以上实施方式仅用于说明本发明,而并非对本发明的限制,有关技术领域的普通技术人员,在不脱离本发明的精神和范围的情况下,还可以做出各种变化和变型,因此所有等同的技术方案也属于本发明的范畴,本发明的专利保护范围应由权利要求限定。The above embodiments are only used to illustrate the present invention, but not to limit the present invention. Those of ordinary skill in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all Equivalent technical solutions also belong to the category of the present invention, and the scope of patent protection of the present invention should be defined by the claims.

Claims (5)

1. a kind of birefringence detection means based on sweep polarization optical coherence tomography is it is characterised in that this device bag Include frequency swept laser(1), optical modulator(2), erbium-doped fiber amplifier(3), coupler(4), the first optical fiber(5), the second optical fiber (6), palarization multiplexing wave multiplexer(7), semiconductor optical amplifier(8), circulator(9), Polarization Controller(10), photo-detector (11), microwave signal wave filter(12), microwave signal amplifier(13), microwave signal shunt(14), oscillograph(15)And remittance Poly- lens(16);
Frequency swept laser(1)Output end and optical modulator(2)Input connect, optical modulator(2)Output end and er-doped Fiber amplifier(3)Input connect, erbium-doped fiber amplifier(3)Output end and coupler(4)Input connect, coupling Clutch(4)Output end respectively pass through the first optical fiber(5)With the second optical fiber(6)With palarization multiplexing wave multiplexer(7)Input even Connect, palarization multiplexing wave multiplexer(7)Output end and semiconductor optical amplifier(8)Input connect, semiconductor optical amplifier(8) Output end and circulator(9)First port(901)Connect, circulator(9)Second port(902)By plus lens (16)Focus the light on biological sample, and pass through plus lens(16)Reflected light is sent back to circulator(9)Second port (902), circulator(9)The 3rd port(903)With Polarization Controller(10)Input connect, Polarization Controller(10)Defeated Go out end and photo-detector(11)Input connect, photo-detector(11)Output end and microwave signal wave filter(12)Input End connects, microwave signal wave filter(12)Output end and microwave signal amplifier(13)Input connect, microwave signal puts Big device(13)Output end and microwave signal shunt(14)Input connect, microwave signal shunt(14)First output Port(1401)With oscillograph(15)Input connect, microwave signal shunt(14)The second output port(1402)With light Modulator(2)Microwave modulated terminal connect.
2., according to the birefringence detection means based on sweep polarization optical coherence tomography described in claim 1, it is special Levy and be, described the first optical fiber(5)Length and the second optical fiber(6)Length unequal.
3. the birefringence detection means based on sweep polarization optical coherence tomography described in a kind of utilization claim 1 Detection method is it is characterised in that this detection method includes procedure below:Using frequency swept laser(1)Send continuous light wave, light The optically modulated device of ripple(2)Modulation and erbium-doped fiber amplifier(3)After amplification, by coupler(4)It is coupled into the first optical fiber(5) With the second optical fiber(6)In, palarization multiplexing wave multiplexer(7)By the first optical fiber(5)With the second optical fiber(6)The modulated optical signal of output is multiple With generating the modulated optical signal of vertical polarization, two vertical polarization are respectively aligned to semiconductor optical amplifier(8)Transverse electric mode With TM mode direction, by control semiconductor optical amplifier(8)Bias current, obtain compensate after vertical polarization light modulation letter Number, using circulator(9)Vertical polarization light modulating signal after compensating is passed through plus lens(16)Directive biological tissue samples, Then this vertical polarization light modulating signal is reflected by biological tissue samples, forms the reflected light carrying biological tissue's information, reflection Light passes through plus lens(16), return loop device(9)In, by circulator(9)The 3rd port(903)Reach Polarization Controller (10)In, Polarization Controller(10)Control the transmission polarization state of reflected light, through photo-detector(11)Output microwave signal, microwave is believed Number through microwave signal wave filter(12)After filtering, by microwave signal amplifier(13)Amplify, by microwave signal shunt(14) Branch is two-way, and a road feeds back to optical modulator(2)In, form closed loop optoelectronic oscillation loop, another road exports to oscillograph (15)In, the frequency of measurement microwave signal.
4. according to the detection of the birefringence detection means based on sweep polarization optical coherence tomography described in claim 3 Method is it is characterised in that described the first optical fiber(5)With the second optical fiber(6)The modulated optical signal of output closed by palarization multiplexing Ripple device(7)Generate the modulated optical signal of vertical polarization, two vertical polarization are respectively aligned to semiconductor optical amplifier(8)Horizontal stroke Electric mould and TM mode direction, by controlling semiconductor optical amplifier(8)Bias current, control its birefringence effect, with compensate Affected by stress, temperature and make what photoelectricity hybrid loop structure resonance cavity length occurred to change, realized calibration detection.
5. according to the detection of the birefringence detection means based on sweep polarization optical coherence tomography described in claim 3 Method is it is characterised in that through semiconductor optical amplifier(8)Realize stress, the vertical polarization light modulating signal after temperature-compensating, Through circulator(9)Through plus lens(16)Directive biological tissue samples, reflected light is subject to the backscattering of biological tissue samples Rate and birefringence joint effect are so that the loop configuration resonator parameter of photoelectricity mixing changes, and then change it and shake The frequency of raw microwave signal of dissipating one's fortune, thus the detection realizing the birefringence change to biological tissue is changed in oscillograph (15)The frequency of middle measurement microwave signal.
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