Spectrum detection device and method based on fixed air gap etalon

Abstract

The invention relates to a spectrum detection device and method based on a fixed air gap etalon, and belongs to the technical field of optical atmosphere data measurement. According to the invention, the fixed air gap etalon with a steep transmittance curve is used as a core component, and the spectral characteristic measurement of a measured optical signal is realized by using the transmittance change of echo signals under different frequencies and different broadening under the fixed air gap etalon; the device can realize high-precision identification and extraction of atmospheric scattering signal information, and provides support for application verification of an optical atmospheric data sensing technology based on direct detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical atmospheric data measurement, and in particular relates to a spectrum detection device and method based on a fixed air gap etalon. Background Art

[0002] In the field of optical atmospheric data measurement, active laser detection technology is used to measure atmospheric parameters through the linear information of atmospheric scattering signals. It is necessary to design a set of spectral detection devices with extremely high spectral resolution to extract spectral information of laser detection signals. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] Aiming at the high-precision and high-resolution measurement requirements faced in the field of optical atmospheric data detection, the present invention proposes a spectral detection device based on a fixed air gap etalon to achieve high-precision recognition and extraction of atmospheric scattering signal information.

[0005] (II) Technical solution

[0006] In order to solve the above technical problems, the present invention provides a design method for a spectrum detection device based on a fixed air gap etalon, the device uses the transmittance change of echo signals under different frequencies and different broadening under the fixed air gap etalon to achieve the spectral characteristic measurement of the measured light signal, the device is designed to include a collimating lens 1, a spectroscope group 2, a fixed air gap etalon 3, a receiving optical element 4 and a detector 5;

[0007] The fixed air gap etalon 3 comprises two completely parallel circular plates, and four positions uniformly distributed circumferentially on one of the plates are coated to form four detection channels. When parallel light is incident, interference fringes are generated, so that the transmittance of the fixed air gap etalon 3 changes regularly. The center frequency, bandwidth, and free spectrum range parameters of the transmittance curve are determined by the gap between the two plates.

[0008] The detection light signal is input by the collimating lens 1. The light signal output by the collimating lens 1 after collimation is equally divided by the spectroscope group 2 and enters each detection channel of the fixed air gap etalon 3 respectively. Then, the light signal output by each detection channel is coupled to the detector 5 by the receiving optical element 4 located at the rear end of the fixed air gap etalon 3 for signal recognition, thereby realizing the detection of the spectral characteristics of the measured light signal.

[0009] Preferably, the fixed air gap standard adjusts the gap value of each detection channel through coating, so that there is a fixed difference in each transmittance curve, and the transmittance curve of each detection channel has the following characteristics: 1) having the same free spectrum range and bandwidth parameters, 2) the peak-to-peak spacing between center frequencies is equal and arranged in ascending order; 3) the product of the peak-to-peak spacing and the detection channel is equal to the free spectrum spacing.

[0010] Preferably, the fixed air gap etalon 3 further comprises a housing, and the two flat plates are fixed on the inner wall of the housing. The light aperture of each detection channel of the fixed air gap etalon 3 is 30 mm, and the diameter of the fixed air gap etalon 3 is 160 mm.

[0011] Preferably, the parameters of the fixed air gap etalon are set as follows: the free spectrum range is 10.2 GHz, the bandwidth is 1.7 GHz, and the center frequencies of the detection channels are 0 GHz, 2.55 GHz, 5.1 GHz, and 7.65 GHz, respectively.

[0012] Preferably, the input end of the collimating lens 1 is an optical fiber input, with specific parameters of NA0.22 and a core diameter of 105 microns. The diameter of the light spot output by the collimating lens 1 after collimating the optical signal is 25 mm.

[0013] Preferably, the optical diameter of the beam splitter assembly 2 is 25 mm.

[0014] Preferably, the device has a spectral detection capability with a single measurement period of 10.2 GHz and a resolution better than 1.7 GHz.

[0015] The invention also provides a spectrum detection device designed based on the method.

[0016] The invention also provides a method for using the device.

[0017] The present invention also provides an optical atmospheric data measurement method implemented based on the device.

[0018] (III) Beneficial effects

[0019] A spectral detection device based on a fixed air gap etalon provided by the present invention uses a fixed air gap etalon with a steep transmittance curve as a core component, and utilizes the transmittance changes of echo signals under different frequencies and different broadenings under the fixed air gap etalon to achieve spectral feature measurement of the measured light signal. The device can achieve high-precision recognition and extraction of atmospheric scattering signal information, and provide support for the application verification of optical atmospheric data sensing technology based on direct detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a front view of the spectrum detection device of the present invention;

[0021] Figure 2 is a side view of the spectrum detection device of the present invention;

[0022] Figure 3 Schematic diagram of a fixed air gap etalon in the device of the present invention, wherein a is a side view of the etalon, and b is a schematic diagram of a detection channel on the etalon;

[0023] Figure 4 Schematic diagram of the transmittance curve of the spectral detection device under typical parameters. DETAILED DESCRIPTION

[0024] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0025] The present invention provides a spectrum detection device based on a fixed air gap etalon, which utilizes the transmittance changes of echo signals with different frequencies and different broadenings under the fixed air gap etalon to achieve the measurement of the spectrum characteristics of the measured light signal.

[0026] The spectrum detection device is composed of a collimating lens 1, a beam splitter group 2, a fixed air gap standard 3, a receiving optical element 4 and a detector 5. The structural diagram of each component is shown in FIG. Figure 1 , Figure 2 shown.

[0027] The core of the spectral detection device is a fixed air gap etalon 3 with four detection channels, refer to Figure 3 The fixed air gap etalon 3 is composed of two completely parallel circular plates. Four positions evenly distributed circumferentially on one of the plates are coated to form four detection channels. When parallel light is incident, interference fringes will be generated in the outgoing light due to the interference phenomenon, causing the transmittance of the etalon to change regularly. The parameters of the transmittance curve, such as the center frequency, bandwidth, and free spectral range, are determined by the gap distance between the two plates.

[0028] The fixed air gap standard adjusts the gap distance value of each detection channel through coating, so that there are fixed differences in each transmittance curve. The transmittance curve of each detection channel has the following characteristics: 1) having the same free spectral range (FSR) and bandwidth parameters, 2) the peak-to-peak spacing between center frequencies is equal and arranged in ascending order; 3) the product of the peak-to-peak spacing and the detection channel is equal to the free spectral spacing.

[0029] The spectral detection device with the above characteristics constitutes a periodic spectral detection device with a measurement range of free spectral spacing and a spectral resolution better than the peak-to-peak spacing, which can realize high-precision spectral signal recognition in a small range and meet the requirements of the optical atmospheric data measurement system.

[0030] The parameters of the fixed air gap etalon for setting the spectrum detection device are: free spectrum range is 10.2GHz, bandwidth is 1.7GHz, and the relative center frequencies of each detection channel are 0GHz, 2.55GH, 5.1GHz, and 7.65GHz respectively. The transmittance curve is shown in Figure 4 As shown, a single measurement cycle of 10.2 GHz and a spectral detection capability with a resolution better than 1.7 GHz are achieved.

[0031] The detection light signal is input by the collimating lens 1, and after being equally divided by the spectroscope group 2, it enters each detection channel of the fixed air gap etalon 3 respectively, and then is coupled to the detector 5 by the receiving optical element 4 located at the rear end of the fixed air gap etalon 3, thereby realizing the effective detection of the spectral characteristics.

[0032] The input end of the collimating lens 1 of the spectrum detection device is an optical fiber input, with specific parameters of NA0.22, core diameter of 105 microns, and the spot diameter output by the collimating lens 1 after collimating the light signal is 25mm. The optical diameter of the beam splitter group 2 is 25mm, the aperture of each detection channel of the fixed air gap etalon 3 is 30mm, and the diameter of the fixed air gap etalon 3 is 160mm (including the shell). The optical signal of each detection channel is coupled to the detector 5 by the receiving optical element 4 at the rear end for signal recognition.

[0033] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A design method for a spectral detection device based on a fixed air gap etalon, characterized in that: The device utilizes the transmittance change of echo signals with different frequencies and different widths under a fixed air gap etalon to achieve spectral feature measurement of the measured light signal. The device is designed to include a collimating lens (1), a beam splitter group (2), a fixed air gap etalon (3), a receiving optical element (4) and a detector (5); The fixed air gap etalon (3) comprises two completely parallel circular plates, and four positions uniformly distributed circumferentially on one of the plates are coated respectively to form four detection channels. When parallel light is incident, interference fringes are generated, so that the transmittance of the fixed air gap etalon (3) changes regularly. The center frequency, bandwidth and free spectrum range parameters of the transmittance curve are determined by the gap between the two plates. The detection light signal is inputted by a collimating lens (1). The light signal outputted by the collimating lens (1) is equally divided by a beam splitter group (2) and then enters each detection channel of a fixed air gap etalon (3). Then, the light signal outputted by each detection channel is coupled to a detector (5) by a receiving optical element (4) located at the rear end of the fixed air gap etalon (3) for signal recognition, thereby realizing the detection of the spectral characteristics of the measured light signal.

2. The method according to claim 1, characterized in that The fixed air gap etalon adjusts the gap value of each detection channel by coating, so that there is a fixed difference between each transmittance curve, and the transmittance curve of each detection channel has the following characteristics: 1) have the same free spectrum range and bandwidth parameters, 2) the peak-to-peak spacing between the center frequencies is equal and arranged in ascending order; 3) the product of the peak-to-peak spacing and the detection channel is equal to the free spectrum spacing.

3. The method according to claim 2, characterized in that The fixed air gap etalon (3) also comprises a shell, two flat plates are fixed on the inner wall of the shell, the light aperture of each detection channel of the fixed air gap etalon (3) is 30 mm, and the diameter of the fixed air gap etalon (3) is 160 mm.

4. The method according to claim 3, characterized in that The parameters of the fixed air gap etalon are set as follows: the free spectrum range is 10.2 GHz, the bandwidth is 1.7 GHz, and the center frequencies of the detection channels are 0 GHz, 2.55 GHz, 5.1 GHz, and 7.65 GHz, respectively.

5. The method according to claim 4, characterized in that The input end of the collimating lens (1) is an optical fiber input, with specific parameters of NA0.22 and a core diameter of 105 microns. The diameter of the light spot output by the collimating lens (1) after collimating the optical signal is 25 mm.

6. The method according to claim 5, characterized in that The optical diameter of the beam splitter group (2) is 25 mm.

7. The method according to claim 6, characterized in that The device has a spectral detection capability with a single measurement period of 10.2 GHz and a resolution better than 1.7 GHz.

8. A spectrum detection device designed based on the method according to any one of claims 1 to 7.

9. A method of using the device as claimed in claim 8.

10. A method for measuring optical atmospheric data based on the device according to claim 8.

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