CN216652273U - Vital sign device based on single-ended single-fiber Michelson fiber interferometer - Google Patents

Abstract

The utility model relates to a vital sign device based on a single-ended single-fiber Michelson optical fiber interferometer, comprising a light source, a photoelectric detector, an optical fiber coupler, a single-ended single-fiber Michelson optical fiber interferometer, a micro-control unit MCU and a terminal; The optical fiber coupler is connected with the light source, the photodetector and the single-ended single-fiber Michelson fiber interferometer respectively; the photodetector is also connected with the terminal through the MCU. The utility model combines the reference arm and the interference arm without separate arrangement, effectively avoids the influence of the environment on the reference arm, and has a single-ended single-fiber minimalist structure; not only coherent light sources but also incoherent light sources are available.

Description

Vital sign device based on single-ended single-fiber Michelson fiber interferometer

technical field

The utility model relates to the technical field of vital sign parameter monitoring, in particular to a vital sign device based on a single-ended single-fiber Michelson fiber interferometer.

Background technique

Vital signs, including heart rate and respiration rate, are important parameters for maintaining normal physical activity, and are also important indicators for doctors to judge the severity of the disease. In health care, measuring the patient's heart rate and breathing rate is an essential step, especially in health care that requires continuous monitoring of heart rate and breathing rate. However, the current monitors used for patient care need to be in direct contact with the patient's skin when measuring respiration rate and heart rate. Generally, electrodes are attached to the body, and tape with sensors is also required. Not only does this cause pain or discomfort to the patient, leading to patient unease and poor compliance, but more importantly, the patient cannot be measured for long-term vital signs parameters, thus limiting many new applications.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a vital sign device based on a single-ended single-fiber Michelson fiber interferometer without isolating the sensing arm and the reference arm, with low cost and high sensitivity.

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

A vital sign device based on a single-ended single-fiber Michelson fiber interferometer, comprising a light source, a photodetector, an optical fiber coupler, a single-ended single-fiber Michelson optical fiber interferometer, a micro-control unit MCU and a terminal; the optical fiber coupler and The light source, the photodetector and the single-ended single-fiber Michelson fiber interferometer are respectively connected; the photodetector is also connected to the terminal through the MCU.

Further, the light source adopts FP, DFB, VECEL light source or incoherent broadband light source.

Further, the optical fiber coupler adopts a 1×2 optical fiber coupler, two ends of the 1×2 optical fiber coupler are connected to the output end of the light source, and one end is connected to the input end of the single-ended single-fiber Michelson fiber interferometer, Terminal 3 is connected to the photodetector.

Further, the single-ended single-fiber Michelson fiber interferometer includes a single-mode fiber and a fiber reflection lens; the single-ended single-fiber Michelson fiber interferometer is installed in the curved part.

Further, the upper and lower surfaces of the curved part have a concave-convex structure.

Further, the bending part is a mesh part.

Compared with the prior art, the utility model has the following beneficial effects:

1. The core and the cladding of the single-ended single-fiber Michelson fiber interferometer sensor adopted by the present invention serve as both the reference arm and the sensing arm, without isolating the sensing arm and the reference arm, with low cost and high sensitivity;

2. The utility model effectively avoids the influence of the environment on the reference arm, and has a minimalist structure of single-ended single-fiber; not only coherent light sources but also incoherent light sources are available.

Description of drawings

Fig. 1 is the structural representation of the present utility model;

2 is a schematic structural diagram of a single-ended single-fiber Michelson fiber interference sensor in an embodiment of the present invention;

3 is a schematic diagram of a package of a single-ended single-fiber Michelson fiber interference sensor in an embodiment of the present invention;

FIG. 4 is the original test data in an embodiment of the present invention.

Detailed ways

The present utility model will be further described below in conjunction with the accompanying drawings and embodiments.

Please refer to FIG. 1 , the present utility model provides a vital sign device based on a single-ended single-fiber Michelson fiber interferometer, including a light source, a photodetector, a 1×2 coupler, a single-ended single-fiber Michelson fiber interferometer, a micro-controller Unit MCU and terminal: The light source 11 is connected to the 2 ports of the 1×2 coupler through the transmission fiber, and then the 1 port of the coupler is connected to the single-ended single-fiber Michelson fiber interferometer 13 through the transmission fiber; 3 ports of the 1×2 coupler 12 It is connected to the photodetector 14; the MCU15 is connected to the photodetector 14, and the host computer/smartphone 16 is connected to the MCU15 to transmit data through Bluetooth. The host computer is generally a PC or a smart phone, and carries a vital sign parameter extraction and analysis algorithm module. Vital sign parameter extraction and analysis algorithms can also be performed in the MCU15.

Preferably, the light source adopts FP, DFB, VECEL light source or incoherent broadband light source. All fibers are single mode fibers.

Preferably, the optical fiber coupler adopts a 1×2 optical fiber coupler, two ends of the 1×2 optical fiber coupler are connected to the output end of the light source, one end is connected to the input end of a single-ended single-fiber Michelson fiber interferometer, and three ends are connected. Connect with photodetector.

Referring to Figure 2, in this embodiment, the single-ended single-fiber Michelson fiber interferometer is integrally connected to form a single continuous strip with a core and a cladding, one end is connected to port 1 of a 1×2 fiber coupler, and the other An optical fiber with a Michelson fiber interferometer configuration at one end is installed in the upper and lower bending parts. Preferably, the upper and lower bending parts can be mesh parts or other concave-convex parts, the function of which is to increase the external disturbance to the optical fiber. The single-ended single-fiber Michelson fiber interferometer is made of a single-mode fiber with an inner and outer core diameter of 9/125um or a fiber of other sizes by tapering and fusion sintering; the diameter of the taper waist of the double-tapered fiber is 50 microns; Michael The fiber reflection lens in the Xun fiber interferometer is 300 microns in diameter, and the sensor length is less than 15 cm. The optical fiber reflection lens can be coated with a metal film to improve the reflectivity.

In this embodiment, the MCU can be connected to a host computer or a mobile phone through a wireless transmission method such as Bluetooth, so as to ensure the portability of the overall device. The vital sign parameter extraction and analysis algorithm module in the host computer or mobile phone is used to process the original signal output by the photodetector, and then obtain the vital sign parameter information.

Example 1:

In this embodiment, a single-ended single-fiber Michelson fiber-based interferometer adopts a double-tapered fiber-optical fiber reflection lens structure, the structure of which is shown in FIG. 2 .

The single-mode optical fiber selected is the Single-mode Optical Fiber ITU-T G.652.D model of CORNING Company, with a core diameter of 9 microns and a cladding diameter of 125 microns. The distance from the biconical fiber to the fiber reflection lens is denoted as L. According to the principle of total reflection of light, in general, light is confined in the fiber core for propagation. In the Michelson fiber interferometer with this structure, the incident light just propagates in the core before reaching the bi-taper fiber, and when it reaches the bi-taper fiber, the cladding mode is excited due to the mismatch of the mode field diameters. The light that originally only transmitted in the core is divided into two beams and transmitted forward, one part is still transmitted along the core, and the other part enters the cladding. When light is transmitted to the fiber reflective lens, the cladding and core modes are reflected and transmitted along the core and cladding. When the core mode and cladding mode returning along the original path meet the taper waist in the double-cone fiber again, the light in the cladding and the light in the core are coupled again to form interference.

Its theoretical formula is as follows:

是耦合系数，

是传感臂和参考臂的相位差。耦合系数

、传感臂和参考臂的相位差

随着外界环境变量的变化而变化，从而通过检测I_out就可以知晓外界被测量的变化情况。与其它发明不同，本发明主要是利用外界环境变量（振动幅度和频率)扰动光纤反射透镜使耦合系数和相位发生变化从而I_out发生变化。通过解调I_out信号即可得到外界环境变量（比如振动的幅度和频率)。where I _out and I _in are the light intensity of the outgoing light and the light intensity of the incident light, respectively,

is the coupling coefficient,

is the phase difference between the sensing arm and the reference arm. Coupling coefficient

, the phase difference between the sensing arm and the reference arm

It changes with the changes of the external environment variables, so that the measured changes in the outside world can be known by detecting I _out . Different from other inventions, the present invention mainly utilizes external environmental variables (vibration amplitude and frequency) to disturb the optical fiber reflection lens to change the coupling coefficient and phase so that _Iout changes. The external environmental variables (such as the amplitude and frequency of vibration) can be obtained by demodulating the I _out signal.

The host computer or mobile phone can obtain vital sign parameter information by analyzing the signal collected by the photodetector.

The above are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (8)

1. a vital sign device based on single-ended single-fiber Michelson optical fiber interferometer, is characterized in that, comprises light source, photodetector, optical fiber coupler, single-ended single-fiber Michelson optical fiber interferometer, micro-control unit MCU and terminal; The optical fiber coupler is respectively connected with the light source, the photodetector and the single-ended single-fiber Michelson fiber interferometer; the photodetector is also connected with the terminal through the MCU. 2 . The vital sign device based on a single-ended single-fiber Michelson fiber interferometer according to claim 1 , wherein the light source adopts an FP, DFB, VECEL light source or an incoherent broadband light source. 3 . 3. The vital sign device based on a single-ended single-fiber Michelson fiber interferometer according to claim 1, wherein the fiber coupler adopts a 1×2 fiber coupler, and 2 of the 1×2 fiber coupler are used. The end is connected to the output end of the light source, the 1 end is connected to the input end of the single-ended single-fiber Michelson fiber interferometer, and the 3 end is connected to the photodetector. 4. The vital sign device based on a single-ended single-fiber Michelson fiber interferometer according to claim 1, wherein the single-ended single-fiber Michelson fiber interferometer comprises a single-mode biconical fiber and a fiber reflection lens; The single-ended single-fiber Michelson fiber interferometer is mounted in a curved part. 5 . The vital sign device based on a single-ended single-fiber Michelson fiber interferometer according to claim 4 , wherein the curved part has a concave-convex structure. 6 . 6 . The vital sign device based on a single-ended single-fiber Michelson fiber interferometer according to claim 4 , wherein the bending part is a mesh part. 7 . 7 . The vital sign device based on a single-ended single-fiber Michelson fiber interferometer according to claim 4 , wherein the optical fiber reflection lens adopts a metal or dielectric film-coated optical fiber reflection lens with a mirror function. 8 . 8 . The vital sign device based on a single-ended single-fiber Michelson fiber interferometer according to claim 4 , wherein the fiber reflection lens has a reflectivity of 10%-100%. 9 .

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