WO2018035813A1 - Dual-frequency optical source - Google Patents

Abstract

A dual-frequency optical source, comprising a pump unit (10), a coupling unit (20), and a resonant cavity unit disposed on an output optical path of the coupling unit (20). The resonant cavity unit comprises a common optical path section and a non-common optical path section. A gain medium (30) is provided at the common optical path section. The non-common optical path section comprises a first section (401) and a second section (402) configured for independent transmission and having different optical path lengths. The common optical path section and the first section (401) form a first resonant cavity. The common optical path section and the second section (402) form a second resonant cavity. The dual-frequency optical source further comprises an output unit (50) used to output a laser beam of a first frequency generated by the first resonant cavity and a laser beam of a second frequency generated by the second resonant cavity. By employing the special resonant cavity unit, and sharing the pump unit and gain medium between the two resonant cavities, the dual-frequency optical source of the present invention generates laser beams of different frequencies, and enables heterodyne interference with laser beams of two frequencies. The present invention facilitates frequency adjustment, provides a large frequency range for adjustment, and has excellent resistance to interference.

Description

 Dual frequency light source

 [0001] The present invention belongs to the field of optical technologies, and in particular, to a dual-frequency light source.

 Background technique

 [0002] The development of laser technology has strongly promoted the development of optical communication, nonlinear optics, high-resolution optics, etc., especially in precision interferometry. Precision interferometry mainly uses the laser wavelength as the "ruler" and uses the interference principle to measure various parameters such as acceleration, displacement, angular displacement and so on. Since the wavelength of light is on the order of nm, its resolution is unmatched by electrical and magnetic components. Laser interferometers are widely used in precision and ultra-precision length measurement due to their unique large measurement range, high resolution and high measurement accuracy. The lasers used primarily for laser interference are single-frequency lasers and dual-frequency lasers. The laser measuring instrument used earlier is a single-frequency interferometer based on a single-frequency laser, but the interferometer is seriously affected by environmental factors, especially in the measurement environment, and the measurement distance is longer, which is more affected. Mainly because it produces a constant current signal, the attenuation of the luminescence energy, the presence of air turbulence, and the change of the background light intensity at large distances will cause the beam to shift, which inevitably causes the laser beam to The intensity changes, resulting in a drift of DC light intensity and level. Since single-frequency interferometers are largely limited by DC amplifier drift, optical receiver sensitivity, and laser power fluctuations, single-frequency laser interferometers are difficult to exploit in high-precision measurements.

 [0003] The dual-frequency laser interferometer developed on the basis of a single-frequency laser interferometer is a heterodyne interferometer, and its most remarkable feature is the use of carrier technology to convert the measured physical quantity information into a frequency modulated or amplitude modulated signal. It overcomes the problem of DC drift of the measurement signal of ordinary single-frequency interferometer, has many advantages such as small signal noise, anti-environment interference, allowing multi-channel multiplexing of light source, etc. It is widely used in advanced manufacturing industry and nanotechnology field as distance measurement and speed measurement. , vibration measurement, shape measurement, real position measurement and control.

[0004] Currently used dual-frequency lasers mainly include Zeeman dual-frequency laser, dual longitudinal mode dual-frequency laser, and birefringence dual-frequency laser proposed by Professor Zhang Shulian of Tsinghua University. The Zeeman dual-frequency laser utilizes the Zeeman effect, which refers to the phenomenon that if the light source is placed in a magnetic field, the line from the source will split. Zeeman dual-frequency laser output frequency difference is generally below 1MHz, generally not used for high-speed precision laser heterodyne interferometry. The double longitudinal mode laser realizes the laser output of two longitudinal modes in one laser cavity by controlling the cavity length of the laser, etc., and the vertical mode frequency difference can reach 600MHz-lGHz (corresponding laser tube length is 150mm-250mm) . The birefringence dual-frequency laser is an optical element with a birefringence effect such as quartz crystal, calcite, etc. inserted in a single longitudinal mode laser cavity, so that the laser in the cavity is split into o-light and e with different optical resonant cavity lengths. Light, these two orthogonal linearly polarized dual-frequency laser oscillating outputs have a frequency difference between 3 and 40 MHz, and the required frequency difference can be obtained by adjusting the stress of the birefringent crystal.

[0005] Among the above three dual-frequency lasers, the common feature is that the laser frequency adjustment is difficult, and the frequency difference adjustment range is limited. For example, the Zeeman frequency difference can only be adjusted in a relatively small range, the double longitudinal mode. The laser frequency difference can only be adjusted over a relatively large range, while the birefringence dual frequency can only be adjusted in a certain range in the middle. In addition, the laser resonators of the two frequencies of these dual-frequency lasers are completely shared in the geometric optical path, and the two frequencies interact with each other. When changing one frequency of the laser, it often affects another frequency, and is difficult to adjust the frequency.

 [0006] An object of the present invention is to provide a dual-frequency light source, which aims to solve the problem that the frequency adjustment range of the conventional dual-frequency light source is small and the frequency adjustment is difficult.

 Problem solution

 Technical solution

 The present invention is achieved by a dual-frequency light source comprising a pumping unit for generating pump light, a resonant cavity unit, and a coupling unit for coupling the pumping light to the resonant cavity unit The resonant cavity unit includes a common optical path segment and a non-common optical path segment, the common optical path segment is provided with a gain medium, and the non-common optical path segment includes a first segment and a first transmission that are independently transmitted and have different optical paths. a second segment, the common optical path segment and the first segment form a first resonant cavity, the common optical path segment and the second segment form a second resonant cavity, and the coupling unit will be the pump a light beam is coupled into the gain medium to effect particle beam inversion of the gain medium, the dual frequency light source further comprising a first frequency laser and the second resonant cavity for generating the first resonant cavity An output unit that produces a second frequency laser output.

 Advantageous effects of the invention

 Beneficial effect

The dual frequency light source provided by the present invention has the following advantages: [0009] 1. The dual-frequency light source has two resonant cavities (a first resonant cavity and a second resonant cavity), and the two resonant cavities have a common part (common path optical section), and also have different parts (first sub-point) Segment and second segment), the optical paths of the first segment and the second segment are different, causing the first cavity and the second cavity to generate different frequencies, and obtaining a dual-frequency laser, the dual-frequency source is different from two independent The combination of the single-frequency light source, the first resonant cavity and the second resonant cavity share the same gain medium and the same pumping unit, so that the generated dual-frequency laser can realize heterodyne interference and can be used for precise measurement of various physical quantities, and The laser generated by two independent single-frequency lasers cannot interfere with heterodyne.

 [0010] 2. Since the non-common optical path is present, the first segment and the second segment are independent of each other, so adjusting the frequency of one of the laser resonators does not affect the frequency of the other laser cavity, so the frequency is changed conveniently. Able to achieve wideband frequency adjustment range;

 [0011] 3. Due to the existence of the common optical path segment, the external environment change such as temperature has substantially the same influence on the frequency of the two resonant cavities, and the heterodyne interference is performed by using the first frequency laser and the second frequency laser, and the frequency difference is This effect can be counteracted, so the dual-frequency source has a strong anti-interference.

 Brief description of the drawing

 DRAWINGS

 1 is a schematic structural diagram of a first dual-frequency light source according to a first embodiment of the present invention;

2 is a schematic structural diagram of a second dual-frequency light source according to a first embodiment of the present invention;

3 is a schematic structural diagram of a first dual-frequency light source according to a second embodiment of the present invention;

4 is a schematic structural diagram of a second dual-frequency light source according to a second embodiment of the present invention;

5 is a schematic structural diagram of a third dual-frequency light source according to a second embodiment of the present invention;

6 is a schematic structural diagram of a dual-frequency light source according to a third embodiment of the present invention.

Embodiments of the invention

 The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

 [0019] The specific implementation of the present invention is described in detail below with reference to specific embodiments:

Referring to FIG. 1 , an embodiment of the present invention provides a dual-frequency light source, which is specifically capable of generating two different frequencies. The light source of the laser includes a pump unit 10, a coupling unit 20, and a cavity unit, wherein the pump unit 10 emits pump light, and the coupling unit 20 couples the pump light to the cavity unit. The resonant cavity unit includes a common optical path segment and a non-common optical path segment, wherein the common optical path segment is provided with a gain medium 30, and the non-common optical path segment includes a first segment 401 and a second segment that are independently transmitted and have different optical paths. The segment 402, the common optical path segment and the first segment 401 form a first resonant cavity, and the common optical path segment and the second segment 402 form a second resonant cavity, the dual-frequency light source further comprising a second resonant cavity The first frequency laser and the output unit 50 of the second frequency laser output generated by the second cavity. The dual-frequency light source is a dual-cavity light source, that is, a first resonant cavity and a second resonant cavity, and the two resonant cavityes have a common optical path, and there is also an independent non-shared optical path, that is, the first segment 401 and The second segment 402, because the optical paths of the first segment 401 and the second segment 402 are different, causes the first cavity and the second cavity to generate a first frequency laser and a second frequency laser having different frequencies. Also, since the two resonant cavities share the same gain medium 30 and pump unit 10, the dual-frequency source is different from the conventional combination of two single-frequency sources.

 [0021] Specifically, there are many means for forming the first segment 401 and the second segment 402 to form a certain optical path difference, for example, the first segment 401 and the second segment 402 have the same transmission medium and different lengths, or The first segment 401 and the second segment 402 have the same transmission medium, the same length but a crystal that changes the optical path on the first segment 401 or the second segment 402, etc., and the embodiment is not limited to the above. The means produces an optical path difference.

 [0022] The dual-frequency light source provided by the embodiment of the invention has the following advantages:

 [0023] 1. The dual-frequency light source has two resonant cavities (a first resonant cavity and a second resonant cavity), and the two resonant cavities have a common part (common path optical section), and also have different parts (first sub-point) Segment 401 and second segment 402), the optical paths of the first segment 401 and the second segment 402 are different to generate different frequencies, and a dual-frequency laser is obtained, which is different from the combination of two independent single-frequency sources. The first resonant cavity and the second resonant cavity share the same gain medium 30 and the same pumping unit 10, so that the generated dual-frequency laser can realize heterodyne interference and can be used for precise measurement of various physical quantities, and two independent The laser generated by the single-frequency laser cannot interfere with heterodyne.

 [0024] 2. Since there is a non-common optical path, the first segment 401 and the second segment 402 are independent of each other, so adjusting the frequency of one of the laser resonators does not affect the frequency of the other laser cavity, so the frequency is changed conveniently. , can also achieve broadband frequency adjustment range;

[0025] 3. Due to the existence of a common optical path segment, the influence of external environment changes such as temperature on the frequency of the two resonant cavities Basically the same, in the heterodyne interference using the first frequency laser and the second frequency laser, the frequency difference can offset this effect, so the dual-frequency source has strong anti-interference.

 As a modification of the embodiment of the present invention, as shown in FIG. 3, when the pump unit and the coupling unit are free space, the dual-frequency light source further includes a pumping unit 10 and the coupling unit 20 disposed between the pump unit 10 and the coupling unit 20 . A collimating focusing unit 60 for collimating and focusing the pumping light into the coupling unit 20. Specifically, the type and structure of the coupling unit 20 can be reasonably selected according to the transmission medium (fiber or free space) of the dual-frequency source.

 In the embodiment of the present invention, the common optical path segment includes a first common path segment on the side of the gain medium 30 and a second common path segment on the other side of the gain medium 30, that is, the gain medium 30 is located in the common On the Chengguang section, the first segment 401 and the second segment 402 in the non-common optical path segment are parallel optical paths, and are connected between the first common segment and the second common segment, specifically the first segment. One end of the segment 401 and one end of the second segment 402 are commonly connected to one end of the first common path segment, and the other end of the first segment 401 and the other end of the second segment 402 are commonly connected to one end of the second common segment . The gain medium 30 emits light to the first common section and the second common section, and forms a first frequency laser through the first resonant cavity (ie, the first common section, the second common section, and the first section 401). The two resonant cavities (the first common section, the second common section, and the second section 402) form a second frequency laser, and the first frequency laser and the second frequency laser have different frequencies and can be used for heterodyne interference.

 [0028] Further, one end of the first segment 401 and one end of the second segment 402 may be commonly connected to one end of the common optical path segment by the first beam splitting unit 701, and the other end of the first segment 401 and the first segment The other end of the two segments 402 may be commonly connected to the other end of the common optical path segment by the second optical splitting unit 702. Specifically, the type and structure of the first and second beam splitting units can be reasonably selected according to the transmission medium (optical fiber or free space) of the dual-frequency source.

 [0029] The following is divided according to different transmission media, and the present invention is further illustrated by several specific embodiments:

 [0030] Embodiment 1:

[0031] As shown in FIG. 1, the dual-frequency light source provided by the first embodiment of the present invention has the above-mentioned basic structure of the above-described dual-frequency light source, and the repeated description thereof will not be repeated here. Further, in this embodiment, the transmission mediums of the common optical path segment, the first segment 401, and the second segment 402 are all optical fibers. The pumping unit 10 is connected to the coupling unit 20 via an input fiber 801. The coupling unit 20 can be a wavelength division multiplexer. The coupling unit 20 is connected to the gain medium 30 through the first optical fiber 802. The gain medium 30 is an independent gain device. Both sides of the common optical path The first optical fiber 802 and the second optical fiber 803 may be combined with the first optical fiber 802 or the second optical fiber 803, that is, the first optical fiber 802 or the second optical fiber 803 may be included in the first optical fiber 802 or the second optical fiber 803. The gain material itself is the gain fiber. The first optical fiber 802 and the second optical fiber 803 are transmission media of a common optical path segment. The first segment 401 and the second segment 402 respectively use the third fiber 804 and the fourth fiber 805 as a transmission medium, and the other end of the first fiber 802 is connected to the first segment 4 01 through the first beam splitting unit 701 ( One end of the third optical fiber 804) and one end of the second segment 402 (fourth optical fiber 805) are connected to the first segment 401 through the second beam splitting unit 702 at the other end of the second optical fiber 803 (the third optical fiber 804) The other end and the other end of the second segment 402 (fourth fiber 805).

[0032] In this embodiment, the first beam splitting unit 701 and the second beam splitting unit 702 may adopt a coupler with a high split ratio (for example, 95:5 or more), or a circulator, and the circulator is a Multi-port device, wherein light can only be circulated in a single direction in the circulator, and the opposite direction is isolated. The circulator can accurately transmit the first frequency laser through the third optical fiber 804, so that the second frequency laser passes through the fourth Optical fiber 805 transmission

[0033] In order to further prevent the first frequency laser and the second frequency laser from being disturbed by the reverse laser, an isolator 90 may be provided on each of the third optical fiber 804 and the fourth optical fiber 805. Further, the first frequency laser and the second frequency laser in this embodiment are reversely transmitted.

 [0034] In the present embodiment, the first frequency laser and the second frequency laser are output by the output unit 50, specifically, the first segment 401 and the second segment 402 (ie, the third fiber 804 and the fourth fiber). 805) An output unit 50, that is, a first output unit 501 and a second output unit 502, are provided, as shown in FIG. It is also possible to provide the first output unit 501 and the second output unit 502 in the common optical path section to output the first frequency laser and the second frequency laser, respectively. An output unit 503 for outputting the first frequency laser and the second frequency laser may also be disposed on the common optical path segment, as shown in FIG.

 [0035] In this embodiment, the laser is transmitted in the resonant cavity with loss. In order to avoid the optical power difference between the first resonant cavity and the second resonant cavity being too large, each of the third optical fiber 804 and the fourth optical fiber 805 may be An adjustable attenuation unit 100 is provided, or an adjustable attenuation unit 100 is provided on either one.

[0036] In this embodiment, a single longitudinal mode unit 110 may be disposed on the first optical fiber 802 or the second optical fiber 803 of the common optical path segment, or in the first segment 401 and the second segment 402 (ie, A single longitudinal mode unit 110 is disposed on each of the three optical fibers 804 and the fourth optical fiber 805) for implementing a single longitudinal mode of the laser to achieve a high phase of the laser Dry, even close to an ideal coherent light source. Specifically, the single longitudinal mode unit 110 may be a narrow band filter, or may be a unit composed of two collimating lenses and an FP interferometer therebetween.

[0037] Embodiment 2:

 The second embodiment of the present invention also has the basic structure of the dual-frequency light source described above, and is not repeated here. Different from the first embodiment, the optical transmission medium of the dual-frequency light source of the embodiment is a full free space. As shown in Fig. 3, the transmission mediums of the common optical path section, the first segment 401 and the second segment 402 are free spaces. The pumping unit 10 outputs the pump light to the coupling unit 20 in the air, or is further transmitted to the coupling unit 20 through the collimating focusing unit 60, and the pumping light enters the common path optical section via the coupling unit 20. The gain medium 30 is located in the common optical path segment, and may be located on the first common path segment or the second common path segment. One end of the first segment 401 and one end of the second segment 402 pass through the first beam splitting unit 701. One end of the first common section is connected, and the other end of the first section 401 and the other end of the second section 402 are connected to one end of the second common section by the second beam splitting unit 702. The transmission medium of the first common section, the second common section, the first section 401 and the second section 402 are all free spaces.

 [0039] The gain medium 30 may be an independent gain device, or the gain medium 30 may be a gain gas, and the gain gas is sealed by a container, and the two ends of the container are directly connected to adjacent devices without gaps, or the container is The ends are sealed and there is a free space from adjacent devices.

 Further, a collimation focusing unit 60 may be disposed between the pump unit 10 and the coupling unit 20.

 [0041] Further, the coupling unit 20 can adopt a two-color mirror. As shown in FIG. 3, the pump light is incident into the common optical path segment through the dichroic mirror, and the plurality of mirrors 120 and the dichroic mirror form a closed optical path. One part of the optical path is a common optical path section, and the other part is a non-common optical path section, that is, a first segment 401 and a second segment 40 2 . The common optical path segment is divided into a first common section and a second common section by a non-common optical path segment, and both ends of the first segment 401 and the second segment 402 pass through the first combined light splitting unit 701, respectively. And the second combined light splitting unit 702 is connected between the first common section and the second common section. The first common section, the second common section and the first section 401 are first resonant cavities, and the first common section, the second common section and the second section 402 are second resonant cavities.

 Referring to FIG. 3, regarding the laser output, an output unit that can output the first frequency laser and the second frequency laser may be disposed in the common optical path section. Specifically, it may be an output mirror 504 having two output directions. The first frequency laser and the second frequency laser can be directly outputted in the two output directions.

[0043] Further referring to FIG. 4, a prism 505 and a half reverse may be further disposed after the output mirror 504. The half mirror 506 can output the first frequency laser and the second frequency laser in the same direction. Specifically, a prism 505 is disposed in one output direction of the output mirror 504, and a half-reverse half mirror 506 is disposed in another output direction of the output mirror 504. The first frequency laser is reflected by the prism 505 to the half-reverse half mirror 506, and second The frequency laser is output directly from the output mirror 504 to the half mirror half 506, and the two laser beams are output in the same direction at the half mirror half 506, and are separated by using 吋.

[0044] Further referring to FIG. 5, an output unit, that is, a first output unit 501 and a second output unit 502, may be respectively disposed in the first segment 401 and the second segment 402, respectively outputting a first frequency laser and a second Frequency laser.

 [0045] In this embodiment, the first output unit 501 and the second output unit 502 may also be disposed in the common optical path segment.

, respectively outputting the first frequency laser and the second frequency laser, which are not shown in the figure.

[0046] Further, an isolator may be disposed on each of the first segment 401 and the second segment 402 as in the first embodiment.

90.

 Further, a single longitudinal mode unit 110 may be disposed on each of the first segment 401 and the second segment 402 as in the first embodiment, or a single longitudinal mode unit 110 may be disposed in the common optical path segment.

Further, the adjustable attenuation unit 100 may also be disposed on the first segment 401 or the second segment 402 as in the first embodiment. Alternatively, an adjustable attenuation unit 100 is provided on each of the first segment 401 and the second segment 402.

[0049] Embodiment 3:

 [0050] The third embodiment of the present invention also has the basic structure of the dual-frequency light source described above, and is not repeated here. Different from the first embodiment, the optical transmission medium of the dual-frequency light source of the embodiment adopts optical fiber and free space mixing. . As shown in FIG. 6, the common optical path segment adopts a free space, and a circular optical path is formed by the dichroic mirror and the plurality of mirrors 120. The first segment 401 and the second segment 402 are optical fibers, specifically, the first segment 401 and The second segment 402 is transmitted using a fifth fiber 806 and a sixth fiber 807, respectively. The gain medium 30 is located in the free space of the common optical path segment, and the gain medium 30 can be an independent gain device or a gain gas. The gain gas is sealed by a container, and the two ends of the container are directly connected to adjacent devices without gaps, or The ends of the container are sealed and there is a free space from adjacent devices. Both ends of the fifth optical fiber 806 and the sixth optical fiber 807 are connected between the first common path section and the second common path section through the first combined light splitting unit 701 and the second combined light splitting unit 702, respectively.

[0051] Of course, the common optical path segment can also be set to optical fiber transmission, and the first segment 401 and the second segment 402 are set. Set to free space transfer. In this case, the gain medium 30 is an independent gain device, and the gain medium 30 can also be combined with the fiber of the common optical path segment, that is, the common optical path segment adopts a gain fiber.

Further, regarding the output of the dual-frequency laser, an output unit 50 capable of outputting the first frequency laser and the second frequency laser may be disposed in the common optical path section. The first output unit 501 and the second output unit 502 may be disposed in the common optical path segment to output the first frequency laser and the second frequency laser respectively, and the first output may be respectively disposed on the fifth optical fiber 806 and the sixth optical fiber 807. The unit 501 and the second output unit 502 output the first frequency laser and the second frequency laser, respectively.

 Referring to FIG. 6 , the output unit 50 is disposed in the common optical path segment 吋, and includes an output mirror 504 , and may further include a prism 505 and a half reverse half lens 506 , specifically, the first frequency laser and the second frequency. The laser can be output through the output mirror 504 in different directions. It is also possible to provide a half-reverse half mirror 506 in one output direction of the output mirror 504, and a prism 505 in the other output direction, through which the first frequency laser light is reflected to the half-reverse half mirror 506, and the second frequency laser light is outputted by the output mirror 504. Directly outputted to the half mirror half 506, the two laser beams are output in the same direction at the half mirror half 506, and are separated by using 吋.

 Further, an isolator 90 may be disposed on each of the first segment 401 and the second segment 402 as in the first embodiment.

 [0055] Further, a single longitudinal mode unit 110 may be disposed on each of the first segment 401 and the second segment 402 as in the first embodiment, or a single longitudinal mode unit 110 may be disposed in the common optical path segment.

[0056] Further, the adjustable attenuation unit 100 may be disposed on the first segment 401 or the second segment 402 as in the first embodiment, or may be disposed on the first segment 401 and the second segment 402. The attenuation unit 100 is adjusted.

[0057] The dual-frequency light source provided by the embodiment of the present invention uses a special resonant cavity unit, that is, two resonant cavities share the same pumping unit 10 and the gain medium 30, that is, lasers of different frequencies can be obtained, and the dual-frequency laser can be used. Heterodyne interference. Compared with the traditional dual-frequency light source, the frequency adjustment is easy, the adjustment range is large, and the interference resistance is strong.

 The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the present invention. Within the scope of protection of the invention.

Claims

 Claim A dual frequency light source, comprising: a pumping unit for generating pump light, a resonant cavity unit, and a coupling unit for coupling the pumping light to the resonant cavity unit; the resonant cavity unit a common optical path segment and a non-common optical path segment, wherein the common optical path segment is provided with a gain medium, and the non-common optical path segment includes a first segment and a second segment that are independently transmitted and have different optical paths. The common optical path segment and the first segment form a first resonant cavity, the common optical path segment and the second segment form a second resonant cavity, and the coupling unit couples the pump light to the a particle beam inversion of the gain medium is implemented in the gain medium, the dual-frequency light source further comprising a first frequency laser for generating the first cavity and a second frequency laser generated by the second cavity Output unit for output. A dual-frequency light source according to claim 1, further comprising a collimating focusing unit disposed between said pumping unit and said coupling unit. The dual-frequency light source according to claim 1, wherein the common optical path segment comprises a first common path segment on one side of the non-common optical path segment and another side of the non-common optical path segment a second common section, the first segment and the second segment are connected in parallel between the first common segment and the second common segment, and the light emitted by the gain medium passes through the first resonance The cavity forms the first frequency laser, and the light emitted by the gain medium forms the second frequency laser through the second cavity. The dual-frequency light source according to claim 1, wherein said output unit is disposed in said common path optical path. The dual-frequency light source according to claim 4, wherein said output unit is an output unit that can simultaneously output said first frequency laser and said second frequency laser. A dual-frequency light source according to claim 4, wherein said output unit comprises a first output unit for outputting a first frequency laser and a second output unit for outputting a second frequency laser. A dual-frequency light source according to claim 1, wherein said first segment and said second segment are each provided with said output unit. A dual-frequency light source according to claim 1, wherein: one end of said first segment and One end of the second segment is commonly connected to one end of the common optical path segment by a first beam splitting unit, and the other end of the first segment and the other end of the second segment are shared by a second beam splitting unit Connected to the other end of the common optical path segment.  [Claim 9] The dual-frequency light source according to claim 1, wherein an isolator is provided on each of the first segment and the second segment. [Claim 10] The dual-frequency light source according to claim 1, wherein a single longitudinal mode unit is disposed in the common optical path section, or one of the first segment and the second segment is disposed in each Single longitudinal mode unit [Claim 11] The dual-frequency light source according to claim 1, wherein an adjustable attenuation unit is provided in the first segment and/or the second segment. The dual-frequency light source according to any one of claims 1 to 11, wherein the transmission medium of the common optical path segment, the first segment and the second segment is an optical fiber. The dual-frequency light source according to any one of claims 1 to 11, wherein the transmission medium of the common optical path segment, the first segment and the second segment is a free space. The dual-frequency light source according to any one of claims 1 to 11, wherein the transmission medium of the common optical path segment is a free space, and the first segment and the second segment are The transmission medium is an optical fiber; or the transmission medium of the common optical path segment is an optical fiber, and the transmission medium of the first segment and the second segment is a free space.