CN216652273U

CN216652273U - Based on single-ended single-fiber Michelson optical fiber interferometer vital sign device

Info

Publication number: CN216652273U
Application number: CN202120928786.9U
Authority: CN
Inventors: 陈智浩; 熊灿军
Original assignee: Quanzhou Normal University
Current assignee: Fujian Yingyu Technology Co ltd
Priority date: 2021-04-30
Filing date: 2021-04-30
Publication date: 2022-06-03
Anticipated expiration: 2031-04-30

Abstract

The utility model relates to a vital sign device based on a single-ended single-fiber Michelson optical fiber interferometer, which comprises 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, wherein the single-ended single-fiber Michelson optical fiber interferometer is connected with the MCU; the optical fiber coupler is respectively connected with the light source, the photoelectric detector and the single-ended single-fiber Michelson optical fiber interferometer; and the photoelectric detector is also connected with the terminal through the MCU. The reference arm and the interference arm are combined without being separately arranged, so that the influence of the environment on the reference arm is effectively avoided, and the reference arm has a simple structure with a single end and a single fiber; not only coherent light sources but also incoherent light sources are available.

Description

Based on single-ended single-fiber Michelson optical fiber interferometer vital sign device

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 optical fiber interferometer.

Background

The vital signs including heart rate, respiratory rate, etc. are important index parameters for maintaining normal activities of the body and also important index for doctors to judge the severity of the illness. In health care, measuring the heart rate and the respiration rate of a patient is an essential step, especially in health care where continuous monitoring of the heart rate and the respiration rate is required. However, in the current monitor for patient care, when measuring the respiration rate and the heart rate, the monitor needs to be directly contacted with the skin of the patient, generally, electrodes are adhered on the body, and adhesive tapes with sensors need to be bound. Not only does this cause pain or discomfort to the patient, resulting in patient discomfort and poor compliance, but more importantly, the inability to take long-term vital sign parameter measurements of the patient, limits many new applications.

Disclosure of Invention

In view of this, the present invention provides a single-ended single-fiber michelson optical fiber interferometer based vital sign apparatus, which does not need to isolate a sensing arm and a reference arm, and has low cost and high sensitivity.

In order to achieve the purpose, the utility model adopts the following technical scheme:

a vital sign device based on a single-ended single-fiber Michelson optical fiber interferometer comprises 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 respectively connected with the light source, the photoelectric detector and the single-ended single-fiber Michelson optical fiber interferometer; and the photoelectric detector is also connected with the terminal through the MCU.

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

Furthermore, the optical fiber coupler is a 1 × 2 optical fiber coupler, 2 ends of the 1 × 2 optical fiber coupler are connected to the output end of the light source, 1 end is connected to the input end of the single-ended single-fiber michelson optical fiber interferometer, and 3 ends are connected to the photodetector.

Further, the single-ended single-fiber michelson fiber interferometer comprises a single-mode fiber and a fiber reflecting lens; the single-ended single-fiber Michelson optical fiber interferometer is arranged in the bending part.

Further, the upper surface and the lower surface of the bending part are provided with concave-convex structures.

Further, the bending part adopts a gauze part.

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

1. the fiber core and the cladding of the single-ended single-fiber Michelson optical fiber interferometer sensor are used as a reference arm and a sensing arm, the sensing arm and the reference arm do not need to be isolated, and the single-ended single-fiber Michelson optical fiber interferometer sensor is low in cost and high in sensitivity;

2. the utility model effectively avoids the influence of the environment on the reference arm and has a simple structure with single end and single fiber; not only coherent light sources but also incoherent light sources are available.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of a single-ended single-fiber Michelson optical fiber interferometric sensor according to an embodiment of the utility model;

FIG. 3 is a schematic diagram of a single-ended single-fiber Michelson optical fiber interferometric sensor package according to an embodiment of the utility model;

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

Detailed Description

The utility model is further explained below with reference to the drawings and the embodiments.

Referring to fig. 1, the present invention provides a vital sign device based on a single-ended single-fiber michelson optical fiber interferometer, which includes a light source, a photodetector, a 1 × 2 coupler, a single-ended single-fiber michelson optical fiber interferometer, a micro control unit MCU, and a terminal: the light source 11 is connected with the 2 ports of the 1 × 2 coupler through a transmission optical fiber, and then the 1 port of the coupler is connected with the single-ended single-fiber Michelson optical fiber interferometer 13 through the transmission optical fiber; the 3 ports of the 1 × 2 coupler 12 are connected with the photodetector 14; the MCU15 is connected with the photoelectric detector 14, and the upper computer/smart phone 16 is connected with the MCU15 through Bluetooth to transmit data. The upper 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 may also be performed in the MCU 15.

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 is a 1 × 2 optical fiber coupler, wherein 2 ends of the 1 × 2 optical fiber coupler are connected to the output end of the light source, 1 end is connected to the input end of the single-ended single-fiber michelson optical fiber interferometer, and 3 ends are connected to the photodetector.

Referring to fig. 2, in this embodiment, a single-ended single-fiber michelson fiber interferometer is integrally connected in a single continuous form, and has a core and a cladding, one end of the single-ended single-fiber michelson fiber interferometer is connected to a 1 port of a 1 × 2 fiber coupler, and the other end of the single-ended single-fiber michelson fiber interferometer is installed in upper and lower bending members. Preferably, the upper and lower curved members may be gauze members or other concavo-convex members, which function to increase external perturbations on the optical fibers. The single-ended single-fiber Michelson optical fiber interferometer is prepared by tapering and melting sintering a single-mode optical fiber with the inner core diameter of 9/125um or optical fibers with other sizes; the diameter of the cone waist of the biconical optical fiber is 50 micrometers; the diameter of a fiber reflecting lens in the Michelson fiber interferometer is 300 micrometers, and the length of a sensor is smaller than 15 centimeters. The fiber optic reflective lens may be metallized to improve reflectivity.

In this embodiment, the MCU may be connected to the host computer or the mobile phone through wireless transmission such as bluetooth, so as to ensure the portability of the whole device. And the vital sign parameter extraction and analysis algorithm module in the upper computer or the mobile phone is used for processing the original signal output by the photoelectric detector and then obtaining vital sign parameter information.

Example 1:

in this embodiment, a single-end single-fiber michelson-based optical fiber interferometer is adopted, and a biconical fiber-optical fiber reflecting lens structure is adopted, and the structure is shown in fig. 2.

The Single-mode Optical Fiber ITU-T G.652.D model of CORNING corporation is selected as the Single-mode Optical Fiber, the diameter of the Fiber core is 9 microns, and the diameter of the cladding is 125 microns. Wherein the distance from the biconic fiber to the fiber reflecting lens is denoted as L. Generally, light propagates while being confined in the core by the principle of total reflection of light. In the Michelson fiber interferometer with the structure, incident light only propagates in the fiber core when not reaching the biconical fiber, and a cladding mode is excited due to mismatching of mode field diameters when reaching the biconical fiber. The light originally transmitted only in the core is divided into two beams to be transmitted forward, one part is still transmitted along the core, and the other part enters the cladding. When light is transmitted to the fiber reflecting lens, the cladding mode and the core mode are reflected to be transmitted along the core and the cladding. When the core mode and the cladding mode returning along the original path meet the taper waist in the biconical fiber again, the light in the cladding and the light in the core are coupled again to form interference.

The theoretical formula is as follows:

in the formula I_outAnd I_inRespectively the intensity of the outgoing light and the intensity of the incoming light,

is the coefficient of the coupling, and,

is the phase difference of the sensing arm and the reference arm. Coefficient of coupling

Figure DEST_PATH_605953DEST_PATH_IMAGE004

Phase difference of sensing arm and reference arm

Figure DEST_PATH_523094DEST_PATH_IMAGE006

Changes along with the change of the external environment variable, thereby passing throughDetection I_outThe outside measured change situation can be known. Different from other inventions, the utility model mainly utilizes external environment variables (vibration amplitude and frequency) to disturb the fiber reflecting lens to change the coupling coefficient and the phase so as to obtain the I_outA change occurs. By demodulation of I_outThe signal can then derive the external environment variables (such as amplitude and frequency of vibration).

The upper computer or the mobile phone can obtain the vital sign parameter information by analyzing the signals collected by the photoelectric detector.

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.

Claims

1. A vital sign device based on a single-ended single-fiber Michelson optical fiber interferometer is characterized by 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 respectively connected with the light source, the photoelectric detector and the single-ended single-fiber Michelson optical fiber interferometer; and the photoelectric detector is also connected with the terminal through the MCU.

2. The single-ended single-fiber michelson optical fiber interferometer-based vital sign device of claim 1, wherein the light source is a FP, DFB, VECEL or incoherent broadband light source.

3. The vital sign device based on the single-ended single-fiber michelson optical fiber interferometer of claim 1, wherein the optical fiber coupler is a 1 x 2 optical fiber coupler, wherein 2 ends of the 1 x 2 optical fiber coupler are connected to the output end of the light source, 1 end is connected to the input end of the single-ended single-fiber michelson optical fiber interferometer, and 3 ends are connected to the photodetector.

4. The single-ended single-fiber michelson optical fiber interferometer-based vital sign device of claim 1, wherein the single-ended single-fiber michelson optical fiber interferometer comprises a single-mode biconic optical fiber and a fiber reflecting lens; the single-ended single-fiber Michelson fiber optic interferometer is mounted within a curved member.

5. The single-ended single-fiber michelson optical fiber interferometer-based vital sign device of claim 4, wherein the curved member has a concave-convex structure.

6. The single-ended single-fiber Michelson-based optical fiber interferometer-based vital sign device of claim 4, wherein the bending member is a mesh member.

7. The single-ended single-fiber Michelson optical fiber interferometer-based vital sign device of claim 4, wherein the optical fiber reflecting lens is a metal or dielectric film coated optical fiber reflecting lens with a mirror function.

8. The single-ended single-fiber michelson optical fiber interferometer-based vital sign device of claim 4, wherein the fiber optic reflective lens has a reflectivity of 10% -100%.