High repetition frequency subcarrier laser

Abstract

Seed laser enters a lens to converge a light beam through optical fiber coupling, is subjected to light path turning through a reflecting mirror I, a reflecting mirror II, a reflecting mirror III and a spectroscope I, enters a polaroid so as to enter an upper light path, and sequentially passes through the polaroid I, an optical isolator, a 1 / 2 wave plate and a polarization cylinder. A pumping source emits continuous light which oscillates in a resonant cavity formed by a reflector V and an OC coupling mirror, laser is generated through a gain medium crystal, and pulse laser is generated through electro-optical modulation; the pulse laser and the seed laser are modulated to generate pulse laser carrying subcarrier signals, the OC coupling mirror outputs laser, the frequency doubling crystal performs frequency doubling on the laser to form laser with half wavelength, the laser with original wavelength is filtered out through the spectroscope penetrating through the half wavelength, and finally the spectroscope II changes a light path to output the pulse laser carrying subcarriers. According to the invention, a subcarrier laser signal with high repetition frequency and short pulse can be generated, and the requirement of an underwater laser ranging modulation signal is met.

Description

Technical Field

[0001] The invention relates to a high repetition rate subcarrier laser, in particular to a high repetition rate subcarrier laser with a compact structure, which generates a high repetition rate and short pulse subcarrier laser signal and is suitable for underwater operation, and belongs to the field of laser devices. Background Art

[0002] The ocean has always been rich in natural resources and precious wealth. In recent years, with the rapid development of marine resource development, there has been a huge demand for three-dimensional imaging of marine targets in the fields of seabed topography and geomorphology mapping, marine plant biomass monitoring, national defense and military, etc. Lasers have many advantages such as high collimation, high resolution, monochromaticity and good coherence, and can be widely used in the fields of marine resource surveying, seabed mapping and underwater target detection.

[0003] The brightness, stability, power and wavelength of the laser light source directly affect the detection range, accuracy and resolution of the laser system. Underwater laser long-distance transmission requires high repetition rate, short pulse and high energy. In addition, the laser light source with high repetition rate can effectively reduce the volume of the system and improve the practicality of the system. The blue-green laser with a wavelength between 470nm and 580nm has a lower attenuation degree than other wavelengths when transmitted in water, so it is very suitable as a laser light source for underwater operations. Summary of the invention

[0004] The technical problem to be solved by the present invention is a high repetition rate subcarrier laser, which has the characteristics of compact structure, generating high repetition rate and short pulse subcarrier laser signal and being suitable for underwater operation.

[0005] In order to solve the above technical problems, the technical solution of the present invention is: a high repetition rate subcarrier laser, the innovation of which is: the high repetition rate subcarrier laser includes a seed laser optical path and a pulse laser optical path, the seed laser optical path is incident on the pulse laser optical path after being turned through the polarizer II on the pulse laser optical path; The seed laser optical path includes, in order along the optical path advancing direction, a seed laser, a lens directly opposite to the seed laser, a reflector I with an acute angle of continuous light incident on the lens, a polarizer I directly opposite to the reflector I, an optical isolator directly opposite to the polarizer I, a 1 / 2 wave plate directly opposite to the optical isolator, a reflector II with an acute angle of continuous light incident on the 1 / 2 wave plate, a polarizing tube directly opposite to the reflector II, a reflector III with an acute angle of continuous light incident on the polarizing tube, and a reflector IV with an acute angle of continuous light incident on the reflector III, wherein the reflector IV turns the optical path with an acute angle of continuous light incident on the polarizer II; The pulse laser optical path includes, in sequence along the optical path advancing direction, a pump source, a reflector V pumped by the pump source, an electro-optical Q-switch directly opposite to the reflector V, a quarter wave plate directly opposite to the electro-optical Q-switch, a polarizer II directly opposite to the quarter wave plate, an OC coupling mirror directly opposite to the polarizer II via a working substance, a double frequency crystal directly opposite to the OC coupling mirror, a beam splitter I having an acute angle of continuous light incident on the double frequency crystal, and a beam splitter II having an acute angle of continuous light incident on the beam splitter I.

[0006] Preferably, the seed laser is a picosecond seed laser, and the seed laser is incident on the lens through optical fiber coupling to converge the light beam.

[0007] Preferably, the pump source generates a pulsed laser through the reflector V and the electro-optical Q-switch, the pulsed laser and the seed laser on the seed laser optical path generate a pulsed laser carrying a subcarrier signal through the polarizer II, the pulsed laser carrying the subcarrier signal is output through the OC coupling mirror, the laser is frequency-doubled into a laser with half the wavelength through the doubled frequency crystal, and then the laser with the original wavelength is filtered out through the half-wavelength beam splitter I, and finally the optical path is changed through the beam splitter II and the laser is output.

[0008] Preferably, the reflector I and the reflector II, as well as the reflector II and the reflector III, are symmetrically placed on the seed laser optical path.

[0009] Preferably, the angle at which continuous light is incident on the lens to the reflector I is 45°; the angle at which continuous light is incident on the 1 / 2 wave plate to the reflector II is 45°; and the angle at which continuous light is incident on the polarizing tube to the reflector III is 45°.

[0010] Preferably, the angle at which the continuous light is incident on the reflector III onto the reflector IV is 34°.

[0011] Preferably, the pump source adopts a 808nm semiconductor diode.

[0012] Preferably, the working material is a neodymium-doped yttrium aluminum garnet optical crystal; the electro-optical Q-switching switch is a KD*P crystal; and the double frequency crystal is an LBO crystal.

[0013] Preferably, the angle at which the continuous light from the frequency doubler crystal is incident on the beam splitter I is 45°; the angle at which the continuous light from the beam splitter I is incident on the beam splitter II is 45°.

[0014] Preferably, the reflector IV turns the light path so that the continuous light incident angle is 56° and is incident on the polarizer II.

[0015] The advantages of the present invention are as follows: the pump source generates pulsed laser through the reflector V and the electro-optical Q-switch, the seed laser on the pulsed laser and seed laser optical path generates pulsed laser carrying subcarrier signal through the polarizer II, the pulsed laser carrying subcarrier signal is output through the OC coupling mirror, the laser is frequency-doubled to half wavelength laser through the doubled frequency crystal, the original wavelength laser is filtered out through the half wavelength beam splitter I, and finally the optical path is changed through the beam splitter II and the laser is output. The present invention can generate high repetition rate, short pulse subcarrier laser signal, meet the needs of underwater laser ranging modulation signal, and has a wide range of application prospects.

[0016] Compared with existing technologies: 1. The design structure is compact and stable. Reflector I, reflector II, reflector III, beam splitter I, reflector V and beam splitter II are used to ensure that the cavity volume is not too large. The laser cavity structure is compact and fewer components are used overall, making its structure stable and suitable for use in complex environments.

[0017] 2. The present invention uses electro-optical Q-switching to generate pulsed laser, and modulates the 30 MHz seed laser signal onto the pulsed laser to carry a subcarrier signal, which can not only meet the needs of underwater operations, but also has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0019] Figure 1 It is a structural schematic diagram of a high repetition rate subcarrier laser of the present invention.

[0020] In the figure: 1-seed laser, 2-lens, 3-reflector I, 4-polarizer I, 5-optical isolator, 6-1 / 2 wave plate, 7-reflector II, 8-polarization tube, 9-reflector III, 10-reflector IV, 11-reflector V, 12-electro-optical Q-switch, 13-1 / 4 wave plate, 14-polarizer II, 15-working material, 16-OC coupling mirror, 17-double frequency crystal, 18-beam splitter I, 19-beam splitter II. DETAILED DESCRIPTION

[0021] The high repetition rate subcarrier laser of the present invention comprises a seed laser 1 optical path and a pulse laser optical path, wherein the seed laser 1 optical path is turned and incident on the pulse laser optical path through a polarizer II 14 on the pulse laser optical path; the seed laser 1 optical path comprises, in order along the advancing direction of the optical path, a seed laser 1, a lens 2 directly opposite to the seed laser 1, a reflector I3 with an acute angle of continuous light incident on the lens 2, a polarizer I4 directly opposite to the reflector I3, an optical isolator 5 directly opposite to the polarizer I4, a 1 / 2 wave plate 6 directly opposite to the optical isolator 5, a reflector II 7 with an acute angle of continuous light incident on the 1 / 2 wave plate 6, a polarization tube 8 directly opposite to the reflector II 7, a reflector III 9 with an acute angle of continuous light incident on the polarization tube 8, and a reflector III 9 with an acute angle of continuous light incident on the reflector III 9. The reflector IV10 has an acute angle of incidence, and the reflector IV10 turns the optical path with the continuous light incident angle being an acute angle to be incident on the polarizer II14; the pulse laser optical path includes, in order along the optical path advancing direction, a pump source, a reflector V11 pumped by the pump source, an electro-optical Q-switched switch 12 directly opposite to the reflector V11, a 1 / 4 wave plate 13 directly opposite to the electro-optical Q-switched switch 12, a polarizer II14 directly opposite to the 1 / 4 wave plate 13, an OC coupling mirror 16 directly opposite to the polarizer II14 via the working substance 15, a double frequency crystal 17 directly opposite to the OC coupling mirror 16, a beam splitter I18 with a continuous light incident angle of an acute angle to the double frequency crystal 17, and a beam splitter II19 with a continuous light incident angle of an acute angle to the beam splitter I18.

[0022] The pump source generates pulsed laser through the reflector V11 and the electro-optical Q-switch 12, and the seed laser 1 on the optical path of the pulsed laser and the seed laser 1 generates a pulsed laser carrying a subcarrier signal through the polarizer II14, and the pulsed laser carrying the subcarrier signal is output through the OC coupling mirror 16, and the laser is doubled into a laser with half the wavelength through the double frequency crystal 17, and then the laser with the original wavelength is filtered out through the half-wavelength beam splitter I18, and finally the optical path is changed through the beam splitter II19 and the laser is output. The present invention can generate a high repetition rate, short-pulse subcarrier laser signal, meet the needs of underwater laser ranging modulation signals, and has a wide range of application prospects.

[0023] The seed laser 1 is a picosecond seed laser. The seed laser 1 is incident on the lens 2 through optical fiber coupling to converge the light beam. The reflector I3 and the reflector II7, as well as the reflector II7 and the reflector III9 are symmetrically placed on the optical path of the seed laser 1. The angle of incident light from the lens 2 to the reflector I3 is 45°; the angle of incident light from the 1 / 2 wave plate 6 to the reflector II7 is 45°; the angle of incident light from the polarization tube 8 to the reflector III9 is ​​45°; the angle of incident light from the reflector III9 to the reflector IV10 is 34°.

[0024] The pump source is a 808nm semiconductor diode. The working material 15 is a neodymium-doped yttrium aluminum garnet optical crystal; the electro-optical Q-switch 12 is a KD*P crystal; the frequency doubler crystal 17 is an LBO crystal. The frequency doubler crystal 17 is incident on the beam splitter I 18 with a continuous light angle of 45°; the beam splitter I 18 is incident on the beam splitter II 19 with a continuous light angle of 45°. The reflector IV 10 is incident on the polarizer II 14 with a continuous light incident angle of 56°.

[0025] In the present invention, reflector Ⅰ3 and reflector Ⅱ7, reflector Ⅱ7 and reflector Ⅲ9 are placed symmetrically respectively, and the incident angles of continuous light of reflector Ⅰ3, reflector Ⅱ7, reflector Ⅲ9, beam splitter Ⅰ18 and beam splitter Ⅱ19 are all 45°, the incident angle of beam splitter Ⅰ18 is 34°, and the incident angle of polarizer Ⅱ14 is 56°. Multiple reflectors are used to ensure that the volume of the laser cavity is not too large.

[0026] Specifically: the picosecond seed laser 1 is a 1064nm laser that enters the upper optical path from the lower optical path. The working material 15 used in the upper optical path is Nd:YAG crystal to generate a laser with a wavelength of 1064nm, and a pulsed laser is generated through an electro-optical Q-switched switch 12, wherein the Q-switched frequency is 10Hz; the pulse laser and the seed laser 1 generate a 1064nm pulsed laser carrying a subcarrier signal through modulation, and the laser is output from the OC coupling mirror 16, and then the 1064nm laser is frequency-doubled into a 532nm laser through the LBO doubled frequency crystal 17, and then a beam splitter I 18 that only passes through 532nm is used to prevent the previous 1064nm laser from entering the subsequent optical path, and finally a 532nm pulsed laser carrying a subcarrier is output through a beam splitter II 19.

[0027] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present application should not be determined with reference to the above description, but should be determined with reference to the appended claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a waiver of the subject matter, nor should it be considered that the inventors did not consider the subject matter to be part of the disclosed inventive subject matter.

Claims

1. A high repetition rate subcarrier laser, characterized in that: The high repetition rate subcarrier laser comprises a seed laser optical path and a pulse laser optical path, wherein the seed laser optical path is incident on the pulse laser optical path through the polarizer II on the pulse laser optical path; The seed laser optical path includes, in order along the optical path advancing direction, a seed laser, a lens directly opposite to the seed laser, a reflector I with an acute angle of continuous light incident on the lens, a polarizer I directly opposite to the reflector I, an optical isolator directly opposite to the polarizer I, a 1 / 2 wave plate directly opposite to the optical isolator, a reflector II with an acute angle of continuous light incident on the 1 / 2 wave plate, a polarizing tube directly opposite to the reflector II, a reflector III with an acute angle of continuous light incident on the polarizing tube, and a reflector IV with an acute angle of continuous light incident on the reflector III, wherein the reflector IV turns the optical path with an acute angle of continuous light incident on the polarizer II; The pulse laser optical path includes, in sequence along the optical path advancing direction, a pump source, a reflector V pumped by the pump source, an electro-optical Q-switch directly opposite to the reflector V, a quarter wave plate directly opposite to the electro-optical Q-switch, a polarizer II directly opposite to the quarter wave plate, an OC coupling mirror directly opposite to the polarizer II via a working substance, a double frequency crystal directly opposite to the OC coupling mirror, a beam splitter I having an acute angle of continuous light incident on the double frequency crystal, and a beam splitter II having an acute angle of continuous light incident on the beam splitter I.

2. A high repetition rate subcarrier laser as claimed in claim 1, characterized in that: The seed laser is a picosecond seed laser, and the seed laser is incident on the lens through optical fiber coupling to converge the light beam.

3. A high repetition rate subcarrier laser as claimed in claim 1, characterized in that: The pump source generates a pulsed laser through the reflector V and the electro-optical Q-switch. The pulsed laser and the seed laser on the seed laser optical path generate a pulsed laser carrying a subcarrier signal through the polarizer II. The pulsed laser carrying the subcarrier signal is output through the OC coupling mirror. The laser is frequency-doubled into a laser with half the wavelength through the doubled frequency crystal. The laser with the original wavelength is then filtered out through the beam splitter I that transmits half the wavelength. Finally, the optical path is changed through the beam splitter II and the laser is output.

4. A high repetition rate subcarrier laser as claimed in claim 1, characterized in that: On the seed laser optical path, the reflector I and the reflector II, as well as the reflector II and the reflector III are symmetrically placed.

5. A high repetition rate subcarrier laser as claimed in claim 1, characterized in that: The angle at which continuous light is incident on the lens to the reflector I is 45°; the angle at which continuous light is incident on the 1 / 2 wave plate to the reflector II is 45°; and the angle at which continuous light is incident on the polarizing tube to the reflector III is 45°.

6. A high repetition rate subcarrier laser as claimed in claim 1, characterized in that: The angle at which the continuous light is incident on the reflector III to the reflector IV is 34°.

7. A high repetition rate subcarrier laser as claimed in claim 1, characterized in that: The pump source adopts a 808nm semiconductor diode.

8. A high repetition rate subcarrier laser as claimed in claim 1, characterized in that: The working material is a neodymium-doped yttrium aluminum garnet optical crystal; the electro-optical Q-switching switch is a KD*P crystal; and the double frequency crystal is an LBO crystal.

9. A high repetition rate subcarrier laser as claimed in claim 1, characterized in that: The angle at which the double frequency crystal is incident on the beam splitter I with continuous light is 45°; the angle at which the beam splitter I is incident on the beam splitter II with continuous light is 45°.

10. A high repetition rate subcarrier laser as claimed in claim 1, characterized in that: The reflector IV turns the light path with a continuous light incident angle of 56° to be incident on the polarizer II.

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