Optical fiber spectrometer and in-situ water measurement instrument comprising same

Abstract

An optical fiber spectrometer, comprising a housing, and a slit assembly, a collimating lens, a grating module, a focusing lens module, a reflector module, and a linear array photoelectric detector module which are arranged in the housing; the slit assembly, the collimating lens, the grating module, the focusing lens module, the reflector module, and the linear array photoelectric detector module are provided on the inner periphery of the housing; and during use, incident light passes through the slit assembly, the collimating lens, the grating module, the focusing lens module, the reflector module, and the linear array photoelectric detector module to form a spectrum detection light path. According to the optical fiber spectrometer of the present invention, the angle of the reflector module can be adjusted, and the plane layout of the light path is reduced, so that the optical fiber spectrometer has an elongated appearance and thus can be used in a use scene with limited geometric dimensions.

Description

Fiber optic spectrometer and in-situ water measuring instrument thereof Technical Field

[0001] The present invention belongs to the technical field of optical analysis instruments, and in particular relates to a fiber optic spectrometer and an in-situ water measuring instrument thereof. Background Art

[0002] The optical system structure of a conventional fiber optic spectrometer currently on the market includes a slit module, a collimator, a grating, a focusing lens, and a CCD photodetector. The optical path of this conventional fiber optic spectrometer is a Czerny-Turner (CT) structure, and its optical components are arranged on the same plane. Although it is possible to use small-sized optical components to create a conventional small CT optical path fiber optic spectrometer, the compression of its geometric dimensions on a plane is greatly limited, making it difficult to achieve a slender appearance. Therefore, for some applications that require a small and slender fiber optic spectrometer, such as in-situ water measurement applications, where the sealed cylindrical probe is immersed in water, a slender fiber optic spectrometer is required. This conventional CT optical path spectrometer is difficult to meet practical needs. Similarly, conventional M optical path fiber optic spectrometers have the same shortcomings because their optical components are also arranged on the same plane.

[0003] Therefore, it is necessary to develop a small and slender fiber optic spectrometer for in-situ water quality measurement in different scenarios that can be immersed. Technical issues

[0004] The purpose of the present invention is to provide a fiber optic spectrometer and an in-situ water meter thereof, which solves the problem that the plane layout of the optical path of the existing CT optical path and M optical path fiber optic spectrometer is relatively large, and the optical components are arranged on the same plane, which cannot meet the application of small-sized and slender fiber optic spectrometers. Technical Solutions

[0005] In order to achieve the above-mentioned purpose, the technical solution of the present invention is implemented as follows: a fiber optic spectrometer includes a shell and a slit assembly, a collimator, a grating module, a focusing mirror module, a reflector module and a linear array photodetector module arranged in the shell, the slit assembly, the collimator, the grating module, the focusing mirror module, the reflector module and the linear array photodetector module are arranged on the inner periphery of the shell; when in use, the incident light passes through the slit assembly, the collimator, the grating module, the focusing mirror module, the reflector module and the linear array photodetector module to form a spectral detection optical path.

[0006] In some embodiments, the slit assembly, the grating module, the focusing mirror module, the linear array photodetector module, the collimating mirror and the reflector module are sequentially arranged on the inner periphery of the shell; when in use, the incident light passes through the slit assembly, the collimating mirror, the grating module, the focusing mirror module, the reflector module and the linear array photodetector module in sequence to form a CT-type optical path.

[0007] In some embodiments, the reflector module is provided in two, and the slit assembly, the collimating mirror, the focusing mirror module, the linear array photodetector module, one of the reflector modules, the grating module and the other reflector module are sequentially arranged on the inner periphery of the shell. When in use, the incident light passes through the slit assembly, the other reflector module, the collimating mirror, the grating module, the focusing mirror module, one of the reflector modules and the linear array photodetector module in sequence to form an M-shaped optical path.

[0008] In some embodiments, the slit assembly includes a fiber coupling connector and a slit, wherein the fiber coupling connector is used to fix the optical fiber or the coupling lens.

[0009] In some embodiments, the grating module includes a grating bracket and a grating arranged on the grating bracket, the grating bracket is arranged on the shell, the grating bracket includes a base, a bracket and a rotating shaft, the bracket and the grating are arranged on the base, and the grating is tightly attached to the bracket, the rotating shaft is arranged at the lower end of the base, and the rotating shaft is connected to the shell.

[0010] In some embodiments, an adjustment notch is provided at the upper end of the bracket, and a positioning block is provided on the base near the grating; fixing holes are also provided on both sides of the adjustment notch at the upper end of the bracket.

[0011] In some embodiments, the reflector module includes a reflector bracket and a reflector disposed on the reflector bracket, and the reflector bracket is disposed on the housing.

[0012] In some embodiments, the reflector bracket includes a bracket body, a limit block and a rotating shaft, the limit block is fixed on one side of the bracket body, the rotating shaft is located on the side of the bracket body close to the limit block and is connected to the bracket body, and the rotating shaft is arranged on the shell.

[0013] In some embodiments, a first limiting plate and a second limiting plate for limiting the reflector are extended from the upper edge of the bracket body, and the reflector is arranged in a space formed by the first limiting plate and the second limiting plate.

[0014] Another technical solution of the present invention is achieved as follows: it includes an in-situ water measuring probe housing, the optical fiber spectrometer, a xenon lamp, a control circuit, a transmitting end sealing window, a receiving end sealing window, and an in-situ water measuring probe gap, the optical fiber spectrometer, the xenon lamp, and the control circuit are sealed in the in-situ water measuring probe housing, the transmitting end sealing window is used to seal the through hole of the in-situ water measuring probe housing on the side of the xenon lamp; the receiving end sealing window is used to seal the through hole of the in-situ water measuring probe housing on the side of the optical fiber spectrometer; the transmitting end sealing window and the receiving end sealing window form the in-situ water measuring probe gap, and the optical fiber spectrometer, the xenon lamp, the transmitting end sealing window and the receiving end sealing window are located on the same optical axis to allow light to pass through. Beneficial effects

[0015] Compared to the prior art, the fiber optic spectrometer of the present invention differs in that the optical components are not arranged on the same plane. The addition of an angle-adjustable reflector module significantly reduces the planar layout of the optical path, resulting in a slender fiber optic spectrometer suitable for use in scenarios with limited geometric dimensions. Therefore, the fiber optic spectrometer of the present invention is applied to immersive in-situ water meters for water quality measurement in various scenarios, such as surface water, groundwater, and offshore seawater, to achieve online water quality monitoring without secondary contamination. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a schematic diagram of a CT optical path fiber spectrometer in Example 1 of the present invention;

[0017] FIG2 is a schematic diagram of an M-path optical fiber spectrometer in Example 2 of the present invention;

[0018] FIG3 is a schematic structural diagram of a grating module according to an embodiment of the present invention;

[0019] FIG4 is a schematic structural diagram of a reflector module according to an embodiment of the present invention;

[0020] FIG5 is another structural schematic diagram of a reflector module according to an embodiment of the present invention;

[0021] FIG6 is a schematic structural diagram of a linear array photoelectric detector module according to an embodiment of the present invention;

[0022] FIG7 is a schematic structural diagram of an in-situ water measuring instrument in Example 3 of the present invention;

[0023] FIG8 is a spectrum diagram of the in-situ tester in Example 3 of the present invention.

[0024] In the figure, 1. slit assembly, 2. collimating mirror, 3. grating module, 31. grating bracket, 311. base, 312. bracket, 3121. adjustment notch, 3122. fixing hole, 32. grating, 4. focusing mirror module, 5. reflector module, 51. reflector bracket, 511. bracket body, 5111. first limit plate, 5112. second limit plate, 512. limit block, 52. reflector, 6. linear array photoelectric detector module, 61. linear array photoelectric detector sensitive surface. Best Mode for Carrying Out the Invention

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] In the description of the present invention, it should be clarified that the terms "vertical", "transverse", "longitudinal", "front", "rear", "left", "right", "up", "down", "horizontal", etc. indicating orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not mean that the device or element referred to must have a specific orientation or position, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. 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. Example

[0027] A fiber optic spectrometer provided in Example 1 of the present invention, as shown in Figure 1, includes a housing and a slit assembly 1, a collimating mirror 2, a grating module 3, a focusing mirror module 4, a reflector module 5 and a linear array photodetector module 6 arranged in the housing. The slit assembly 1, the grating module 3, the focusing mirror module 4, the linear array photodetector module 6, the collimating mirror 2 and the reflector module 5 are sequentially arranged on the inner periphery of the housing; when in use, the incident light passes through the slit assembly 1, the collimating mirror 2, the grating module 3, the focusing mirror module 4, the reflector module 5 and the linear array photodetector module 6 in sequence to form a CT-type optical path.

[0028] Using this solution, the fiber optic spectrometer of the present invention differs from existing technologies in that the optical components are not located on the same plane. Adjusting the position of the internal optical components as needed reduces the size of the fiber optic spectrometer and makes it slender. The fiber optic spectrometer of the present invention can be applied to immersive in-situ water meters for water quality measurement in various scenarios, such as surface water, groundwater, and offshore water, enabling online water quality monitoring without secondary contamination.

[0029] In the specific implementation process of this embodiment, the slit assembly 1 includes a fiber coupling joint and a slit, and the fiber coupling joint is used to fix the optical fiber or the coupling lens.

[0030] More specifically, the slit assembly 1 consists of a fiber coupling connector and a slit. The fiber coupling connector is used to secure an optical fiber or coupling lens, which guides the measured light into the slit assembly 1. After passing through the slit, the measured light forms a thin linear light beam that travels to the collimator 2. After being collimated by the collimator 2, the measured light beam travels to the grating module 3. After being diffracted and split by the grating module 3, the light beam forms a spatially continuously distributed monochromatic light beam that travels to the focusing module 4. After being focused by the focusing module 4, the light beam travels to the reflector module 5. After being reflected by the reflector module 5 at a certain angle, such as 45 degrees, the light beam travels to the linear array photodetector 6, where it is focused to form a linear continuously distributed monochromatic light beam. After undergoing photoelectric conversion by the linear array photodetector 6, the measured spectrum is output as an electrical signal.

[0031] In the specific implementation process of this embodiment, as shown in Figure 3, the grating module 3 includes a grating bracket 31 and a grating 32 arranged on the grating bracket 31. The grating bracket 31 is arranged on the shell. The grating bracket 31 includes a base 311, a bracket 312 and a rotating shaft. The bracket 312 and the grating 32 are arranged on the base 311, and the grating 32 is tightly attached to the bracket 312. The rotating shaft is arranged at the lower end of the base 311, and the rotating shaft is connected to the shell.

[0032] In the specific implementation process of this embodiment, as shown in Figure 3, the upper end of the bracket 312 is provided with an adjustment notch 3121, and a positioning block 3111 is provided on the base 311 near the grating 32; the upper end of the bracket 312 is also provided with fixing holes 3122 on both sides of the adjustment notch 3121.

[0033] More specifically, the grating 32 is fixed to the grating bracket 31 by a positioning block 3111, and a tool is used to adjust the rotation of the grating bracket 31 by adjusting the notch 3121. The rotation of the grating bracket 31 is achieved by a rotating shaft, and the rotating shaft is placed in the hole of the CT optical path folding fiber spectrometer in a tight fit. The rotation of the grating bracket 31 is used to adjust the position of the spectral light in the X-axis direction of the linear array photodetector 6 (that is, the direction in which the pixels of the linear array photodetector 6 are arranged in sequence); when the adjustment of the grating bracket 31 is completed, screws are used to fix the grating bracket 31 to the CT optical path folding fiber spectrometer through the fixing holes 3122 on both sides of the adjustment notch 3121. This embodiment is not limited to screws, bolts or pins, and can also be fixed in other fitting ways.

[0034] In a specific implementation process of this embodiment, as shown in FIG. 4 and FIG. 5 , the reflector module 5 includes a reflector bracket 51 and a reflector 52 provided on the reflector bracket 51 . The reflector bracket 51 is provided on the housing.

[0035] In the specific implementation process of this embodiment, as shown in Figures 4 and 5, the reflector bracket 51 includes a bracket body 511, a limit block 512 and a rotating shaft. The limit block 512 is fixed on one side of the bracket body 511, and the rotating shaft is located on the side of the bracket body 511 close to the limit block 512 and is connected to the bracket body 511. The rotating shaft is arranged on the shell.

[0036] During the specific implementation of this embodiment, as shown in Figures 4 and 5, a first limiting plate 5111 and a second limiting plate 5112 for limiting the reflector 52 are extended from the upper edge of the bracket body 511, and the reflector 52 is arranged in a space formed by the first limiting plate 5111 and the second limiting plate 5112.

[0037] More specifically, the reflector 52 is fixed to the reflector bracket 51 and positioned within the space formed by the first and second limit plates 5111, 5112. The first and second limit plates 5111, 5112 limit the reflector 52 in two directions on the same plane. The reflector bracket 51 is rotated by adjusting the limit blocks 512 to adjust the position of the spectral light along the Y-axis of the linear array photodetector 6 (i.e., perpendicular to the direction in which the pixels of the linear array photodetector 6 are arranged).

[0038] Furthermore, as shown in FIG4 , the limit block 512 and the bracket body 511 are L-shaped. The limit block 512 is sequentially provided with a through hole and a screw hole. The limit block 512 is connected to the housing via two connectors. The connectors may be screws or other fastening or jacking components. The connectors are placed into the through holes and tightened to mate with the screw holes on the housing to provide a fastening force. In addition, the connectors are placed into the screw holes and tightened to contact the housing to provide a jacking force. The reflector bracket 51 is rotated and locked by adjusting the tightness of the two connectors. The reflector bracket 51 rotates around a rotating shaft, which is tightly fitted into a hole on the CT optical path fiber spectrometer.

[0039] Furthermore, as shown in Figure 5, the limit block 512 and the bracket body 511 are T-shaped, and there are two through holes symmetrically arranged on the limit block 512. The limit block 512 is connected to the shell through two connecting parts. The connecting parts are screws or other fastening parts. The two connecting parts are placed in the through holes, and the two connecting parts are alternately tightened to match the screw holes on the shell. The rotation of the reflector bracket 51 and the locking and fixing of the reflector bracket 51 are achieved by adjusting the tightness of the two connecting parts. The reflector bracket 51 rotates around the rotating shaft, and the rotating shaft is placed in the hole on the CT optical path fiber spectrometer in a tight fit.

[0040] In the specific implementation process of this embodiment, as shown in FIG6 , a linear array photoelectric detector module 6 is provided with a linear array photoelectric detector photosensitive surface 61 .

[0041] More specifically, the linear array photodetector module 6 includes a linear array photodetector photosensitive surface 61 having a horizontal X-axis and a vertical Y-axis. The linear array photodetector module 6 can be a device such as a CCD, CMOS, or APD array. The linear array photodetector photosensitive surface 61 can be composed of pixels of different sizes, such as 256, 512, 1024, and 2048 pixels. The focused light to be measured is imaged onto the linear array photodetector photosensitive surface 61, perpendicular to the vertical Y-axis of the linear array photodetector photosensitive surface 61, and forms a linear continuous distribution of monochromatic light along the horizontal X-axis of the linear array photodetector photosensitive surface 61. After photoelectric conversion by the linear array photodetector module 6, the measured spectrum can be output as an electrical signal, i.e., the distribution of light intensity along the pixels of the linear array photodetector photosensitive surface 61. If the wavelength of the fiber optic spectrometer of the present invention is calibrated using a standard lamp, the spectrum can also be expressed as the distribution of light intensity along the wavelength.

[0042] The workflow provided by Example 1 of the present invention is as follows: the measured light forms a thin linear light after passing through the slit and is emitted to the collimator 2; after being collimated by the collimator 2, it is emitted to the grating module 3, and after being diffracted and split by the grating module 3, it forms a spatially continuously distributed monochromatic light and is emitted to the focusing lens module 4; the rotation of the grating bracket 31 is adjusted by adjusting the notch 3121 to adjust the position of the spectral light in the X-axis direction of the linear array photodetector 6; after being focused by the focusing lens module 4, it is emitted to the reflector module 5; the rotation of the reflector bracket 51 is achieved by adjusting the limit block 512 to adjust the Y-axis position of the spectral light in the linear array photodetector 6; after being reflected by the reflector module 5 at a certain angle, such as 45 degrees, it is emitted to the linear array photodetector 6 and focused on the linear array photodetector 6 to form a linear continuously distributed monochromatic light. The formed optical path is a CT optical path. After photoelectric conversion by the linear array photodetector 6, the measured spectrum is output as an electrical signal. Example

[0043] A fiber optic spectrometer provided in Example 2 is shown in Figure 2. Two reflector modules 5 are provided. The slit assembly 1, the collimating mirror 2, the focusing mirror module 4, the linear array photodetector module 6, one of the reflector modules 5, the grating module 3 and the other reflector module 5 are sequentially arranged on the inner circumference of the shell. When in use, the incident light passes through the slit assembly 1, the other reflector module 5, the collimating mirror 2, the grating module 3, the focusing mirror module 4, one of the reflector modules 5 and the linear array photodetector module 6 in sequence to form an M-shaped optical path.

[0044] The difference between this embodiment 2 and embodiment 1 is that this embodiment 2 has two reflector modules 5, and uses optical fiber or coupling lens to guide the measured light into the slit assembly 1. After passing through the slit, the measured light forms a thin linear light and is emitted to a reflector module 5 at 45 degrees. After being reflected by the 45-degree reflector module 5, it is emitted to the collimator 2 at an angle of 45 degrees. After being collimated by the collimator 2, it is emitted to the grating module 3. After being diffracted and split by the grating module 3, it forms a spatially continuously distributed monochromatic light and is emitted to the focusing mirror module 4; after being focused by the focusing mirror module 4, it is emitted to another reflector module 5; after being reflected by the other reflector module 5 at a certain angle, such as 45 degrees, it is emitted to the linear array photodetector 6, and is focused on the linear array photodetector 6 to form a linear continuously distributed monochromatic light. After photoelectric conversion by the linear array photodetector 6, the measured spectrum can be output in the form of an electrical signal.

[0045] The workflow provided by Example 2 of the present invention is as follows: the light to be measured forms a thin linear light after passing through the slit and is emitted to a 45-degree reflector module 5. After being reflected by the 45-degree reflector module 5, it is emitted to the collimator 2 at a 45-degree angle. After being collimated by the collimator 2, it is emitted to the grating module 3. After being diffracted and split by the grating module 3, it forms a monochromatic light continuously distributed in space and is emitted to the focusing lens module 4. The rotation of the grating bracket 31 is adjusted by adjusting the notch 3121 to adjust the position of the spectral light in the X-axis direction of the linear array photodetector 6. After passing through the focusing lens After focusing, the light from the module 4 is directed to another reflector module 5; the rotation of the reflector bracket 51 is achieved by adjusting the limit block 512 to adjust the Y-axis position of the spectral light on the linear array photodetector 6; after being reflected at a certain angle, such as 45 degrees, by the other reflector module 5, the light is directed to the linear array photodetector 6 and focused on the linear array photodetector 6 to form a linear continuously distributed monochromatic light. The formed optical path is an M-type optical path. After photoelectric conversion by the linear array photodetector 6, the measured spectrum is output in the form of an electrical signal. Example

[0046] Embodiment 3 of the present invention provides an in-situ water measuring instrument, as shown in Figure 7. In Figure 7, a is an in-situ water measuring probe housing, b is the optical fiber spectrometer in Examples 1 and 2, c is a xenon lamp, d is a control circuit, e is a receiving end sealing window, f is a transmitting end sealing window, and g is an in-situ water measuring probe gap. The in-situ water measuring instrument includes an in-situ water measuring probe housing a, the optical fiber spectrometer b in Examples 1 and 2, a xenon lamp c, a control circuit d, a receiving end sealing window e, a transmitting end sealing window f, and an in-situ water measuring probe gap g. The optical fiber spectrometer b, the xenon lamp c, and the control circuit d are sealed in the in-situ water measuring probe housing a. The transmitting end sealing window f is used to seal the through hole of the in-situ water measuring probe housing a on the side of the xenon lamp c; the receiving end sealing window e is used to seal the through hole of the in-situ water measuring probe housing a on the side of the optical fiber spectrometer b; the transmitting end sealing window f and the receiving end sealing window e form the in-situ water measuring probe gap g. The optical fiber spectrometer b, the xenon lamp c, the transmitting end sealing window f, and the receiving end sealing window e are located on the same optical axis to allow light to pass through.

[0047] More specifically, the fiber optic spectrometer b, xenon lamp c, and control circuit d of the present invention are sealed and fixed within the in-situ water measurement probe housing a. The transmitting-end sealed window f is used to seal the through-hole of the in-situ water measurement probe housing a located on the side of the xenon lamp c and ensure the passage of measurement light. The receiving-end sealed window e is used to seal the through-hole of the in-situ water measurement probe housing a located on the side of the fiber optic spectrometer b of Examples 1 and 2 of the present invention and ensure the passage of measurement light. A gap g in the in-situ water measurement probe is formed between the transmitting-end sealed window f and the receiving-end sealed window e, ensuring that the water being measured is immersed in the measurement optical path. The broad spectrum measurement light, including ultraviolet, visible, and near-infrared light, emitted by the xenon lamp c passes through the transmitting-end sealed window f and enters the water located in the gap g in the in-situ water measurement probe. The measurement light absorbed by the water passes through the receiving-end sealed window e and enters the fiber optic spectrometer b of Examples 1 and 2 of the present invention. The fiber optic spectrometer b measures the water's absorption spectrum, and by comparing it with a pre-stored reference spectrum, the composition and concentration of the water being measured can be calculated.

[0048] Example 3 uses the M-path fiber optic spectrometer in Example 2 to measure the xenon lamp spectrum from 200 nm to 820 nm, as shown in Figure 8. It can be seen that this spectrum covers the spectrum involved in in-situ water measurement, including 220 nm and 275 nm for measuring total nitrogen, 600 nm for measuring chemical oxygen demand (COD), 660 nm for measuring ammonia nitrogen, and 700 nm for measuring total phosphorus.

[0049] The workflow provided by Example 3 of the present invention is as follows: the wide-spectrum measurement light including ultraviolet light, visible light and near-infrared light emitted by the xenon lamp c passes through the sealed window f at the transmitting end and is emitted into the water located in the gap g of the in-situ water measuring probe. The measurement light absorbed by the water passes through the sealed window e at the receiving end and enters the fiber optic spectrometer b of Examples 1 and 2 of the present invention. The absorption spectrum of the water is measured by the fiber optic spectrometer b. After comparing it with a pre-stored reference spectrum, the composition and concentration of the measured water can be calculated to achieve online water quality detection without secondary pollution.

[0050] In summary, the fiber optic spectrometer of the present invention differs from the prior art in that the optical components are not located on the same plane. The addition of the reflector module in the present invention not only allows the angle of the focused spectral beam to be adjusted but also shortens the optical path. The position of the internal optical components can be adjusted as needed, making the fiber optic spectrometer compact. The fiber optic spectrometer of the present invention is applied to in-situ water meters for water quality measurement in various scenarios, such as surface water, groundwater, and offshore seawater, to achieve online water quality detection without secondary pollution.

[0051] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims. Modes for Carrying Out the Invention

[0052] Type here a paragraph describing embodiments of the invention. Industrial Applicability

[0053] Type your industrial applicability description paragraph here. Sequence Listing Free Content

[0054] Type your sequence listing free description paragraph here.

Claims

1. A fiber optic spectrometer, characterized in that: The invention comprises a shell, and a slit assembly (1), a collimator (2), a grating module (3), a focusing mirror module (4), a reflector module (5), and a linear array photodetector module (6) arranged in the shell, wherein the slit assembly (1), the collimator (2), the grating module (3), the focusing mirror module (4), the reflector module (5), and the linear array photodetector module (6) are arranged on the inner periphery of the shell; when in use, incident light passes through the slit assembly (1), the collimator (2), the grating module (3), the focusing mirror module (4), the reflector module (5), and the linear array photodetector module (6) to form a spectral detection light path.

2. The optical fiber spectrometer according to claim 1, characterized in that: The slit assembly (1), the grating module (3), the focusing mirror module (4), the linear array photoelectric detector module (6), the collimating mirror (2) and the reflecting mirror module (5) are sequentially arranged on the inner periphery of the housing; when in use, incident light sequentially passes through the slit assembly (1), the collimating mirror (2), the grating module (3), the focusing mirror module (4), the reflecting mirror module (5) and the linear array photoelectric detector module (6) to form a CT type optical path.

3. The optical fiber spectrometer according to claim 1, characterized in that: The reflector module (5) is provided in two pieces, and the slit assembly (1), the collimator (2), the focusing lens module (4), the linear array photoelectric detector module (6), one of the reflector modules (5), the grating module (3) and the other reflector module (5) are sequentially arranged on the inner periphery of the housing; when in use, incident light sequentially passes through the slit assembly (1), the other of the reflector modules (5), the collimator (2), the grating module (3), the focusing lens module (4), one of the reflector modules (5) and the linear array photoelectric detector module (6) to form an M-shaped optical path.

4. The optical fiber spectrometer according to any one of claims 1 to 3, characterized in that: The slit assembly (1) comprises an optical fiber coupling joint and a slit, wherein the optical fiber coupling joint is used to fix the optical fiber or the coupling lens.

5. The optical fiber spectrometer according to claim 4, characterized in that: The grating module (3) comprises a grating bracket (31) and a grating (32) arranged on the grating bracket (31), wherein the grating bracket (31) is arranged on the housing; the grating bracket (31) comprises a base (311), a bracket (312) and a rotating shaft, wherein the bracket (312) and the grating (32) are arranged on the base (311), and the grating (32) is closely attached to the bracket (312), and the rotating shaft is arranged at the lower end of the base (311), and the rotating shaft is connected to the housing.

6. The optical fiber spectrometer according to claim 6, characterized in that: An adjustment notch (3121) is provided at the upper end of the bracket (312), and a positioning block (3111) is provided on the base (311) at a position close to the grating (32); fixing holes (3122) are also provided at the upper end of the bracket (312) on both sides of the adjustment notch (3121).

7. The optical fiber spectrometer according to any one of claims 1 to 3, characterized in that: The reflector module (5) comprises a reflector bracket (51) and a reflector (52) arranged on the reflector bracket (51); the reflector bracket (51) is arranged on the housing.

8. The optical fiber spectrometer according to claim 7, characterized in that: The reflector bracket (51) comprises a bracket body (511), a limit block (512) and a rotating shaft, wherein the limit block (512) is fixedly arranged on one side of the bracket body (511), the rotating shaft is located on a side of the bracket body (511) close to the limit block (512) and is connected to the bracket body (511), and the rotating shaft is arranged on the shell.

9. The optical fiber spectrometer according to claim 8, characterized in that: A first limiting plate (5111) and a second limiting plate (5112) for limiting the position of the reflecting mirror (52) are extended from the upper edge of the bracket body (511), and the reflecting mirror (52) is arranged in a space formed by the first limiting plate (5111) and the second limiting plate (5112).

10. An in-situ water measuring instrument, characterized in that: It includes an in-situ water measuring probe housing, an optical fiber spectrometer as described in any one of claims 1 to 9, a xenon lamp, a control circuit, a transmitting end sealing window, a receiving end sealing window, and an in-situ water measuring probe gap. The optical fiber spectrometer, the xenon lamp, and the control circuit are sealed in the in-situ water measuring probe housing. The transmitting end sealing window is used to seal the through hole of the in-situ water measuring probe housing on one side of the xenon lamp; the receiving end sealing window is used to seal the through hole of the in-situ water measuring probe housing on one side of the optical fiber spectrometer; the transmitting end sealing window and the receiving end sealing window form the in-situ water measuring probe gap, and the optical fiber spectrometer, the xenon lamp, the transmitting end sealing window, and the receiving end sealing window are located on the same optical axis to allow light to pass through.

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