Optical fiber type photodetector, detection system, test system and preparation method

Abstract

The present invention discloses a fiber-optic photodetector, a detection system, a test system and a preparation method. Among them, the fiber-optic photodetector includes an optical fiber and a probe; the probe is arranged at the first end of the optical fiber; a Fabry-Perot interferometric cavity is formed between the first end face and the second end face of the probe; the probe is made of a one-dimensional semiconductor material; the probe is parallel to the optical fiber, and the end face of the first end of the probe corresponds to the end face of the first end of the optical fiber, so that the Fabry-Perot interferometric cavity of the probe is coupled with the optical fiber. In this application, the detection of external light is realized through the modulation of the signal light on the detection light; the influence of dark current on the device is effectively avoided; at the same time, the response time of the detector is greatly improved, and it has the characteristic of sub-millisecond fast response; the detector has a simple structure, is easy to manufacture, and the material is inexpensive; the probe is used for detection, and the diameter of the probe is smaller than that of the optical fiber, so that the detector can detect the light at any position that the probe can reach.

Description

Technical Field

[0001] The present invention relates to the technical field of photodetectors, and particularly to a fiber optic photodetector, a detection system, a test system and a preparation method thereof. Background Art

[0002] A photodetector is a device that converts an optical signal into an electrical signal. Its main principle is that the conductivity of the irradiated material changes due to light radiation, and it is widely used in the fields of optical communication, chemical analysis, optical imaging and biosensing. Photodetectors mainly utilize the photoelectric effect of semiconductor materials. When the energy of incident photons is greater than the band gap of the material, it can absorb photons and generate electron-hole pairs. Under the action of an external electric field, electrons and holes are separated and move directionally, thus generating a photocurrent.

[0003] Traditional photodetectors, such as ultraviolet detectors, use current as the signal source, and inevitably introduce dark current, resulting in reduced sensitivity and slow response of the device. Summary of the Invention

[0004] In order to overcome the problems existing in the prior art, the present invention provides a fiber optic photodetector, comprising:

[0005] An optical fiber;

[0006] A probe disposed at the first end of the optical fiber;

[0007] A Fabry-Perot interference cavity is formed between the first end face and the second end face of the probe; the probe is made of a semiconductor material;

[0008] The probe is parallel to the optical fiber, and the end face of the first end of the probe corresponds to the end face of the first end of the optical fiber so that the Fabry-Perot interference cavity of the probe is coupled with the optical fiber.

[0009] As an improvement of the fiber optic photodetector provided by the present invention, the detector further comprises a tubular structure, the first end of the tubular structure is fixed to the optical fiber; the first end of the probe is located inside the tubular structure, and the second end of the probe protrudes from the tubular structure.

[0010] As an improvement of the fiber optic photodetector provided by the present invention, the tubular structure is a glass tube; the glass tube is located at the first end of the optical fiber, and the end face of the first end of the glass tube is fused with the end face of the first end of the optical fiber.

[0011] As an improvement of the fiber optic photodetector provided by the present invention, the optical fiber comprises a core located inside; the first end of the probe corresponds to the core at the end face of the first end of the optical fiber; the probe is made of a one-dimensional semiconductor material.

[0012] As an improvement of the optical fiber photoelectric detector provided by the present invention, the end face of the first end of the probe is adjacent to the end face of the first end of the optical fiber.

[0013] As an improvement of the optical fiber photoelectric detector provided by the present invention, the optical fiber is a single-mode optical fiber.

[0014] As an improvement of the optical fiber photoelectric detector provided by the present invention, the probe material is any one of ZnO, AlN and GaN.

[0015] As an improvement of the optical fiber photoelectric detector provided by the present invention, the inner diameter of the glass tube matches the diameter of the probe.

[0016] The present application also proposes a fiber-optic photoelectric detection system, comprising: the fiber-optic photoelectric detector as described above, as well as a signal light source and a circulator; the signal light source is connected to the first end of the circulator; the second end of the circulator is connected to the second end of the optical fiber, for inputting signal light into the photoelectric detector; the signal light emitted by the signal light source enters the fiber core after passing through the circulator, and is then shot into the probe; after the light is shot, it is reflected between the two end faces of the first end and the second end of the probe, and the incident light and the reflected light interfere to form an interference peak, which is coupled and transmitted back to the fiber core; the reflected light is output via the fiber core and the third end of the circulator.

[0017] As an improvement of the optical fiber photoelectric detection system provided by the present invention, the optical signal source is a tunable laser, which transmits the optical signal through single-wavelength light.

[0018] As an improvement of the fiber-optic photoelectric detection system provided by the present invention, the detection system also includes a photoelectric detector; the photoelectric detector is connected to the third end of the circulator and is used to convert the optical signal output by the detector into an electrical signal; the detection system also includes an oscilloscope, which is connected to the photoelectric detector.

[0019] As an improvement of the optical fiber photoelectric detection system provided by the present invention, the detection system further includes a spectrometer, and the spectrometer is connected to the third end of the circulator.

[0020] The present application also proposes a test system for an optical fiber photoelectric detector, comprising: the optical fiber photoelectric detector as described above, as well as a signal light source, a circulator, a test light source, and a photoelectric detector; the signal light source is connected to the first end of the circulator; the second end of the circulator is connected to the second end of the optical fiber, and is used to input signal light to the photoelectric detector; the test light source is used to output test light, and the test light is irradiated on the surface of the probe; the photoelectric detector is connected to the third end of the circulator, and is used to convert the optical signal output by the detector into an electrical signal.

[0021] As an improvement to the test system of the fiber-optic photodetector provided by the present invention, the test system further includes an oscilloscope, and the oscilloscope is connected to the photodetector.

[0022] As an improvement to the test system of the fiber-optic photodetector provided by the present invention, the test system further includes an optical chopper and an optical path system; the test light emitted by the test light source is irradiated onto the probe surface after passing through the optical chopper and the optical path system.

[0023] As an improvement to the test system of the fiber-optic photodetector provided by the present invention, the test light source is used to output ultraviolet light.

[0024] This application also proposes a preparation method for a fiber-optic photodetector, including the following steps:

[0025] Remove the coating layer of the optical fiber and cut the end face of the optical fiber flat.

[0026] Fix the first end of the tubular structure to the optical fiber, leaving a certain length of the tubular structure.

[0027] Transfer the probe into the tubular structure, couple the first end of the probe with the end face of the optical fiber, make the end face of the first end of the probe correspond to the core of the end face of the first end of the optical fiber, and expose the second end of the probe from the tubular structure.

[0028] As an improvement to the preparation method of the fiber-optic photodetector provided by the present invention, the tubular structure is a glass tube; the method for fixing the first end of the tubular structure to the optical fiber includes:

[0029] Remove the protective layer of the glass tube and cut the end face of the first end of the glass tube flat.

[0030] Perform discharge fusion on the end face of the first end of the glass tube and the end face of the optical fiber after cutting, so that the glass tube is fixedly connected to the optical fiber cladding.

[0031] As an improvement to the method for transferring the probe into the tubular structure provided by the present invention, the method for transferring the probe into the tubular structure includes:

[0032] Use a focused ion beam to cut the end faces of both ends of the probe to ensure the flatness of both ends.

[0033] After fixedly connecting the glass tube to the optical fiber, adsorb the probe with a tungsten wire, transfer the probe into the glass tube, and make the end face of the first end of the probe adjacent to the end face of the first end of the optical fiber, so that the probe can be well coupled with the end face of the optical fiber.

[0034] The fiber-optic photodetector of this application has the following beneficial effects:

[0035] The fiber optic photodetector of the present application has the signal light propagated by the optical fiber to the probe. The light reflects in the Fabry - Perot interference cavity of the probe to form interference peaks, and finally couples back to the inside of the optical fiber; the external light to be detected irradiates the surface of the probe, changing the refractive index of the semiconductor material, and the position of the interference peak also changes accordingly. Through the modulation of the signal light by the detection light, the detection of the external light is realized; there is no need to use current as the signal source, effectively avoiding the influence of dark current on the device; compared with traditional photodetectors, the response time of the detector is greatly improved at the same time.

[0036] The fiber optic photodetector of the present application is used for the detection of light and has the characteristics of fast response (sub - millisecond); the detector has a simple structure, is easy to manufacture, and uses low - cost materials.

[0037] A probe is used for detection. The diameter of the probe is smaller than that of the optical fiber, enabling the detector to detect light at any position that the probe can reach. Brief Description of the Drawings

[0038] Figure 1 It is a schematic structural diagram of the fiber optic photodetector according to an embodiment of the present invention;

[0039] Figure 2 It is a schematic structural diagram of the fiber optic photodetection system according to an embodiment of the present invention;

[0040] Figure 3 It is a schematic structural diagram of the test system of the fiber optic photodetector according to an embodiment of the present invention.

[0041] Reference Numerals:

[0042] 21 - Second laser;

[0043] 22 - Optical chopper;

[0044] 23 - Mirror;

[0045] 24 - Convex lens;

[0046] 25 - Probe;

[0047] 26 - Tubular structure;

[0048] 27 - Optical fiber; 28 - Circulator;

[0049] 29 - First laser;

[0050] 30 - Photodetector;

[0051] 31 - Oscilloscope. Detailed Description of the Invention

[0052] To enable those skilled in the art to better understand the solution of the present invention, the following will clearly and completely describe the technical solution in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0053] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0054] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0055] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] The following will further describe the technical solution of the present invention in detail through the accompanying drawings and embodiments.

[0057] Figure 1 It is a schematic structural diagram of the fiber optic photodetector 30 according to an embodiment of the present invention.

[0058] The fiber optic photodetector 30 includes an optical fiber and a probe 25.

[0059] The optical fiber 27 is used to propagate optical signals.

[0060] The probe 25 is disposed at the first end of the optical fiber 27.

[0061] The probe 25 is substantially parallel to the extending direction of the optical fiber 27, and the end face of the first end of the probe 25 is disposed corresponding to the end face of the first end of the optical fiber 27. As a preferred solution, the probe 25 and the optical fiber 27 are substantially on the same axis.

[0062] For the convenience of description, the left end of the probe 25 in Figure 1 is referred to as the first end of the probe 25. The Figure 1 right end of the optical fiber 27 in Figure 1 is referred to as the first end of the optical fiber 27, and the left end of the optical fiber 27 in

[0063] is referred to as the second end of the optical fiber 27.

[0063] The end faces of the first end and the second end of the probe 25 are parallel, and a Fabry - Perot interference cavity structure is formed between these two end faces.

[0064] The probe 25 is made of a one - dimensional semiconductor material, and the surface of the probe 25 is used for light detection.

[0065] Both the end face of the probe 25 and the end face of the optical fiber 27 have good flatness. When the probe 25 is disposed at the first end of the optical fiber 27, the end face of the first end of the probe 25 is disposed corresponding to the end face of the first end of the optical fiber 27, and the Fabry - Perot interference cavity of the probe 25 is coupled with the optical fiber 27, enabling light to propagate between the optical fiber 27 and the probe 25.

[0066] The basic working principle of the fiber - type photodetector 30 is as follows: Signal light is input at the second end of the optical fiber 27, and the signal light propagates along the optical fiber 27 to the end face of the first end of the optical fiber 27. When the end face of the first end of the optical fiber 27 is adjacent to the end face of the first end of the probe 25, the light then enters the probe 25 made of semiconductor material from the optical fiber 27. The light is reflected between the two smooth and flat end faces of the probe 25, and the incident light and the reflected light will interfere to form an interference peak, and finally be coupled back into the interior of the optical fiber.

[0067] To avoid the air gap between the end face of the first end of the probe and the end face of the first end of the optical fiber from being too large, which would cause the light field to quickly dissipate to both sides, the end face of the first end of the probe is adjacent to the end face of the first end of the optical fiber, enabling good coupling between the optical fiber 27 and the probe 25 for the propagation of light. The adjacency can be that there is a small gap between the faces or that the faces are in direct contact. The size of the gap between the end face of the first end of the probe and the end face of the first end of the optical fiber affects the coupling efficiency. Ideally, when the end face of the first end of the probe is in direct contact with the end face of the first end of the optical fiber, the coupling efficiency is good.

[0068] If the gap between the end face of the first end of the probe and the end face of the first end of the optical fiber is large, the coupling efficiency is too low. Due to the limitation of the resolution of existing instruments, the detected signal may not be observable and recognizable on existing instruments. To ensure a certain coupling efficiency and make it easy to observe on the instrument, the gap between the end face of the first end of the probe and the end face of the first end of the optical fiber can be appropriately adjusted. In a specific embodiment, the gap between the end face of the first end of the probe and the end face of the first end of the optical fiber can be set to 0 to 10 micrometers.

[0069] Taking ultraviolet light detection as an example, when the fiber optic photodetector 30 is placed in a light detection environment, the probe 25 of the one-dimensional semiconductor material is irradiated by ultraviolet light, which changes the refractive index of the one-dimensional semiconductor material, and the position of the interference peak also changes accordingly, and the light intensity at the original interference peak also changes. The detection of ultraviolet light is achieved through the change amount of the interference peak and the change of the light intensity.

[0070] The Fabry-Perot interferometer cavity of the probe 25 is coupled with the optical fiber 27 to enable light to propagate between the optical fiber 27 and the probe 25; the signal light is propagated from the optical fiber 27 to the probe 25, and the light reflects in the Fabry-Perot interferometer cavity to form an interference peak, and finally is coupled back to the inside of the optical fiber; the external light to be detected irradiates the surface of the probe 25, which changes the refractive index of the semiconductor material, and the position of the interference peak also changes accordingly, thereby realizing the detection of external light;

[0071] The fiber optic photodetector 30 of the present application modulates the detection light through the signal light, does not need to use current as the signal source, and effectively avoids the influence of dark current on the device; at the same time, compared with traditional photodetectors, the response time of the detector is greatly improved;

[0072] The fiber optic photodetector 30 of the present application uses the probe 25 for detection. The diameter of the probe 25 is small, so that the detector can detect the light at any position that the probe can reach.

[0073] In the probe 25 of this specific embodiment, it is a one-dimensional semiconductor material, which is a material with very excellent optical properties. Under light radiation, the generation and recombination of photo-generated carriers greatly improve the response time of the device, and it has the characteristic of fast response; at the same time, its absorption coefficient is large and the preparation cost is low.

[0074] In this specific embodiment, the optical fiber 27 is preferably a single-mode optical fiber. The single-mode optical fiber used for light transmission can also be replaced by other types of optical fibers, but it is necessary to ensure that the mode propagated by the optical fiber 27 is mainly single-mode.

[0075] The optical fiber 27 includes a core located in the innermost layer, as well as a cladding and a coating layer. When the probe 25 is arranged at the first end of the optical fiber 27, the position of the probe 25 corresponds to that of the core to facilitate the propagation of light.

[0076] In a specific embodiment, the probe 25 is made of ZnO material. The probe 25 can also be selected from other one-dimensional semiconductor materials with similar properties such as AlN, GaN, etc. In this specific embodiment, the diameter of the probe 25 can be in the micron, sub-micron, or nano scale.

[0077] In a specific embodiment, the probe 25 is a micro-rod with a diameter of 3 - 7 μm. The optical fiber 27 correspondingly is a micro-nano single-mode optical fiber.

[0078] The diameter of the probe 25 and the diameter of the core can be the same or different, and this application does not limit this. For better understanding, here is a simple explanation of the mode mismatch between the probe and the optical fiber: The probe and the optical fiber are equivalent to two waveguides. The modes in each waveguide can be solved for the guided modes and higher-order modes (solved by Maxwell's equations) based on their own material properties, the shape of the end face, the material of the surrounding medium, etc. When these two waveguides are coupled, it can be understood that under the corresponding boundary conditions (different mode boundary conditions are different), the electric fields of the two waveguides are integrated, and according to theoretical calculations, corresponding calculated values will be obtained. When the probe 25 is coupled with the optical fiber 27, ideally the coupling efficiency is 1; however, in actual situations, it is very difficult to achieve a coupling efficiency of 1. Therefore, it is only necessary to ensure a certain coupling efficiency so that the detected signal can be easily observed and recognized on existing instruments.

[0079] Preferably, a carrier can be provided at the optical fiber 27 to facilitate the fixing of the probe 25. Specifically, the tubular structure 26 can be used as the carrier, and the first end of the tubular structure 26 is fixed to the optical fiber 27. The first end of the probe 25 is located inside the tubular structure 26 to facilitate the coupling of the end face of the optical fiber 27 and the end face of the probe 25; the second end of the probe 25 protrudes from the tubular structure 26 for light detection.

[0080] In this application, the tubular structure 26 can be a glass tube. By fusing the end face of the first end of the glass tube with the end face of the first end of the optical fiber 27, the glass tube is fixedly connected to the optical fiber 27. It can be understood that the glass tube is fixedly connected to the outer layer of the optical fiber 27, thus avoiding the core.

[0081] The function of the tubular structure 26 is to be fixed to the optical fiber 27 at one end and at the same time serve as the carrier of the probe 25. The tubular structure 26 can also have other structures. It can be understood that the above-described embodiment of the glass tube does not serve as a limitation on the tubular structure 26 and its connection method.

[0082] The probe 25 can be inserted inside the glass tube. The glass tube has a certain length to facilitate the fixation and clamping of the probe 25. In a specific embodiment, the length of the glass tube is 30μm ± 10μm. The inner diameter of the glass tube matches the diameter of the probe 25, so that the probe 25 can be inserted into the glass tube but will not fall out.

[0083] After the probe 25 is inserted into the glass tube, the end face of the first end of the probe 25 is adjacent to the end face of the first end of the optical fiber 27.

[0084] The embodiment of the present application also provides a fiber-optic photoelectric detection system, which includes the fiber-optic photoelectric detector 30 as described above, a signal light source, and a circulator 28.

[0085] Among them, the signal light source is used to input signal light to the photoelectric detector 30.

[0086] The signal light source is connected to the first end of the circulator 28, and the second end of the circulator 28 is connected to the second end of the optical fiber 27. The signal light emitted by the signal light source enters the core through the circulator 28 and is coupled into the probe 25 at the end face. After the light enters the probe 25, it is reflected between the two end faces of the first end and the second end of the probe 25. The incident light and the reflected light interfere to form an interference peak and are coupled back to the core. The reflected light is output through the core and the third end of the circulator 28.

[0087] As Figure 2 shown, the signal light source of the present application is the first laser 29, and this laser transmits optical signals through single-wavelength light. The first laser 29 is a tunable laser.

[0088] In one embodiment, the detection system further includes a photoelectric detector 30. The photoelectric detector 30 is connected to the third end of the circulator 28 and is used to convert the optical signal output by the detector into an electrical signal.

[0089] For convenient observation, the detection system further includes an oscilloscope 31. The oscilloscope 31 is connected to the photoelectric detector 30, and the change in the voltage of the electrical signal can be observed through the oscilloscope 31.

[0090] Alternatively, a spectrometer can be used to replace the above photoelectric detector 30 plus oscilloscope 31.

[0091] The signal light transmitted by the first laser 29 enters the optical fiber 27 through the circulator 28 and then enters the probe 25. After the light is reflected back to the circulator 28 and enters the photoelectric detector 30, finally, the change in voltage can be observed through the oscilloscope 31.

[0092] The embodiment of the present application also provides a test system for a fiber-optic photoelectric detector 30, which includes the fiber-optic photoelectric detector 30 as described above, a signal light source, a circulator 28, a photoelectric detector 30, and a test light source.

[0093] The signal light source, the circulator 28, and the photodetector 30 are as described above and will not be elaborated here.

[0094] A test light source, which is used to output test light and irradiate the test light / detection light on the surface of the probe 25. When the test system is used for the detection of ultraviolet light, the test light source is used to output ultraviolet light.

[0095] The test light / detection light irradiated on the surface of the probe 25 needs to be non - continuous light. When the test light source emits continuous light, the test system further includes an optical chopper 22. By controlling the rotation of the optical chopper 22, the switching between light - on and light - off of the detection light can be realized, so as to convert the continuous light into non - continuous "switching light" and make the light intensity undergo "enhancement and weakening" transformation.

[0096] In this application, as Figure 3 shown, the test light source is the second laser 21.

[0097] By irradiating a semiconductor material (especially a one - dimensional semiconductor material) with an externally applied "switching light", the refractive index of the material is changed, the position of the interference peak will also change accordingly, and the light intensity at the original interference peak also changes accordingly, achieving the purpose of optical intensity modulation.

[0098] The test system further includes an optical path system. The test light / detection light emitted by the test light source irradiates on the surface of the probe 25 after passing through a certain path. The optical path system may specifically include a reflector 23 and a convex lens 24.

[0099] In this specific embodiment, the second laser 21 serves as the detection optical signal. After passing through the optical chopper 22, it is focused by the reflector 23 and the convex lens 24 and then irradiates on the surface of the probe 25. By controlling the rotation of the optical chopper 22, the switching between light - on and light - off of the light irradiating on the surface of the probe 25 is realized. The waveform of the electrical signal can be seen through the oscilloscope 31, and the detection of the light to be detected (ultraviolet light) is realized through the continuous change of the high and low levels. At the same time, the response time of the fiber - type photodetector 30 can be obtained through the rising and falling edges of the high and low levels.

[0100] The embodiment of this application also provides a preparation method for a fiber - type photodetector 30, and this method includes the following steps:

[0101] S1, using a cutting knife to flatten the end face of the optical fiber 27;

[0102] S2, fixedly connecting the first end of the tubular structure 26 to the optical fiber 27, and leaving a certain length of the tubular structure 26;

[0103] S3. Transfer the probe 25 into the tubular structure 26, couple the first end of the probe 25 with the end face of the optical fiber 27, make the end face of the first end of the probe 25 correspond to the core of the end face of the first end of the optical fiber 27, and expose the second end of the probe 25 from the tubular structure 26.

[0104] When the tubular structure 26 is a glass tube, the method of fixedly connecting the first end of the tubular structure 26 with the optical fiber 27 in step S2 includes:

[0105] S21. Use a cutting tool to cut the end face of the first end of the glass tube flat.

[0106] S22. Perform discharge fusion on the end face of the first end of the glass tube and the end face of the optical fiber 27 after cutting to fixedly connect the glass tube with the cladding of the optical fiber 27.

[0107] The method of transferring the probe 25 into the tubular structure 26 in step S3 includes:

[0108] Use a focused ion beam to cut the end faces of both ends of the probe 25 to ensure the flatness of both ends.

[0109] After fixedly connecting the glass tube with the optical fiber 27, adsorb the probe 25 with a tungsten wire, transfer the probe 25 into the glass tube, so that the probe 25 can be well coupled with the end face of the optical fiber 27.

[0110] The fiber optic photodetector 30 of the present application has the following beneficial effects:

[0111] The signal light is propagated from the optical fiber 27 to the probe 25, and light is reflected in the Fabry - Perot interferometer cavity of the probe 25 to form an interference peak, and finally coupled back to the inside of the optical fiber; the external light to be detected irradiates the surface of the probe 25, causing the refractive index of the semiconductor material to change, and the position of the interference peak will also change accordingly. By modulating the detection light with the signal light, the detection of external light is realized; effectively avoiding the influence of dark current on the device; at the same time, greatly improving the response time of the detector.

[0112] The fiber optic photodetector 30 of the present application is used for the detection of light and has the characteristics of fast response (sub - millisecond); the detector has a simple structure, is easy to manufacture, and uses low - cost materials; the detector can be directly applied to the field of light (especially ultraviolet light) detection.

[0113] Using a probe for detection, the diameter of the probe is small, so that the detector can detect light at any position that the probe can reach.

[0114] Obviously, the embodiments described above are only a part of the embodiments of this application, rather than all of them. The preferred embodiments of this application are shown in the accompanying drawings, but they do not limit the patent scope of this application. This application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosed content of this application more thorough and comprehensive. Although this application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing specific embodiments, or perform equivalent replacements on some of the technical features. Any equivalent structure that makes use of the content of the specification and drawings of this application, directly or indirectly applied in other related technical fields, is equally within the scope of patent protection of this application.

Claims

1. A preparation method of a fiber optic photodetector, characterized in that The fiber-optic photodetector includes: an optical fiber; a probe disposed at the first end of the optical fiber; the probe forms a Fabry-Perot interferometric cavity between its first-end face and second-end face; the probe is made of a one-dimensional semiconductor material; the probe is parallel to the optical fiber, and the end face of the first end of the probe corresponds to the end face of the first end of the optical fiber so that the Fabry-Perot interferometric cavity of the probe is coupled to the optical fiber; the detector further includes a tubular structure, and the first end of the tubular structure is fixed to the optical fiber; the diameter of the probe is smaller than the diameter of the optical fiber, the first end of the probe is located inside the tubular structure, and the second end of the probe extends outside the tubular structure and is exposed; the optical fiber includes a core located inside; the first end of the probe corresponds to the core at the end face of the first end of the optical fiber; the tubular structure is a glass tube, and the inner diameter of the glass tube matches the diameter of the probe; the glass tube is located at the first end of the optical fiber, and the end face of the first end of the glass tube is fused with the end face of the first end of the optical fiber; the end face of the first end of the probe is adjacent to the end face of the first end of the optical fiber, and the gap between the end face of the first end of the probe and the end face of the first end of the optical fiber is 0 to 10 micrometers; The preparation method includes the following steps: Cut the end face of the optical fiber flat; Fix the first end of the tubular structure to the optical fiber and keep a certain length of the tubular structure; Transfer the probe into the tubular structure, couple the first end of the probe with the end face of the optical fiber, make the end face of the first end of the probe correspond to the core at the end face of the first end of the optical fiber, and make the second end of the probe expose from the tubular structure; Wherein, the tubular structure is a glass tube; The method for fixing the first end of the tubular structure to the optical fiber includes: Cut the end face of the first end of the glass tube flat; Perform discharge fusion on the end face of the first end of the glass tube and the cut-flat end face of the optical fiber to fixedly connect the glass tube to the optical fiber cladding; The method for transferring the probe into the tubular structure includes: Use a focused ion beam to cut the end faces of both ends of the probe to ensure the flatness of both ends; After fixedly connecting the glass tube to the optical fiber, adsorb the probe with a tungsten wire, transfer the probe into the glass tube, and make the end face of the first end of the probe adjacent to the end face of the first end of the optical fiber so that the probe can be well coupled with the end face of the optical fiber.

2. The preparation method according to claim 1, wherein The optical fiber is a single-mode optical fiber.

3. The preparation method according to claim 1, characterized in that, The probe material is any one of ZnO, AlN, and GaN.

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