WO2023123630A1

WO2023123630A1 - Multiband single-frequency laser output system

Info

Publication number: WO2023123630A1
Application number: PCT/CN2022/076627
Authority: WO
Inventors: 董金岩; 张磊; 潘伟巍
Original assignee: 上海频准激光科技有限公司
Priority date: 2021-12-31
Filing date: 2022-02-17
Publication date: 2023-07-06
Also published as: CN116417888A

Abstract

The present disclosure relates to the technical field of laser, and relates to a multiband single-frequency laser output system. The multiband single-frequency laser output system comprises a seed laser module configured to output single-frequency laser having at least two wavelengths; an amplification module configured to increase the power of the laser of each wavelength; and a conversion module configured to perform nonlinear frequency conversion on the amplified laser wavelength.

Description

A multi-band single-frequency laser output system

This disclosure claims the priority of the Chinese patent application with application date of December 31, 2021 and application number 202111668374.7, the entire content of which is incorporated by reference in this disclosure.

technical field

The present disclosure relates to the field of laser technology, in particular to a multi-band single-frequency laser output system.

Background technique

At present, the coverage of conventional fiber lasers is limited. Generally, ytterbium-doped fiber lasers can cover the range of 1000-1100nm, erbium-doped fiber lasers can cover the range of 1530-1600nm, and thulium-doped fiber lasers can cover the range of 1700-2050nm. Raman fiber lasers can partially cover the bands that cannot be covered by rare earth ion-doped fiber lasers. However, it is difficult to realize the laser output from the fiber in the visible light band and the band above 2 microns. Nonlinear frequency conversion technology, such as sum frequency technology, difference frequency technology, frequency doubling technology, etc., can greatly expand the output band of the laser, making it possible to realize the laser below the 1000nm band and the laser above the 2000nm band. In practical applications, one or several output lasers with the same or different wavelengths need to be used at the same time. For example, in the theoretical study of laser cooling OH molecules in Acta Physica, three laser wavelengths of 307.1532nm, 344.9163nm and 349.7659nm are required, corresponding to three laser systems.

Contents of the invention

In view of the above-mentioned problems in the above-mentioned related technologies, a multi-band single-frequency laser output system is provided, the multi-band single-frequency laser output system includes a seed laser module, and the seed laser module is set to output single-frequency lasers with at least two wavelengths; An amplification module, the amplification module is configured to increase the power of each wavelength of laser light; a conversion module, the conversion module is configured to perform nonlinear frequency conversion on the amplified laser wavelength.

Description of drawings

FIG. 1 is an exemplary structural diagram illustrating a multi-band single-frequency laser output system according to some embodiments of the present disclosure.

FIG. 2 is an exemplary schematic diagram illustrating a multi-band single-frequency laser output system according to one or more embodiments of the present disclosure.

FIG. 3 is an exemplary schematic diagram illustrating a multi-band single-frequency laser output system according to one or more embodiments of the present disclosure.

FIG. 4 is an exemplary schematic diagram illustrating a multi-band single-frequency laser output system according to one or more embodiments of the present disclosure.

Detailed ways

The following description with reference to the accompanying drawings is provided to facilitate a comprehensive understanding of various embodiments of the present disclosure defined by the claims and their equivalents. These examples include various specific details to facilitate understanding, but these are to be regarded as exemplary only. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the disclosure. Also, in order to briefly and clearly describe the present disclosure, descriptions of well-known functions and constructions will be omitted in the present disclosure.

An embodiment of the present disclosure provides a multi-band single-frequency laser output system. In order to facilitate understanding of the embodiments of the present disclosure, the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

A multi-band single-frequency laser output system, the multi-band single-frequency laser output system is constructed by connecting the seed laser module, amplification module, conversion module, etc. through optical fibers, using technologies such as multi-seed laser generation, injection, multi-band amplification, and multi-band frequency conversion The method realizes that a laser system outputs single-frequency laser in multiple bands.

Fig. 1 is an exemplary structure diagram of a multi-band single-frequency laser output system provided according to some embodiments of the present disclosure. As shown in Figure 1, in some embodiments, the multi-band single-frequency laser output system may include a seed laser module 1, and the seed laser module is configured to output a single-frequency laser with at least two wavelengths. Laser; an amplification module 2, the amplification module is configured to increase the power of each wavelength of the laser; a conversion module 4, the conversion module is configured to perform nonlinear frequency conversion on the amplified laser wavelength. According to some embodiments of the present disclosure, the multi-band single-frequency laser output system may further include an optical fiber 3 configured to inject the amplified laser light into the conversion module. The multi-band single-frequency laser may include, but not limited to, a laser with a band below 1000 nm and/or a laser with a band above 2000 nm. The seed laser module 1 may include but not limited to a single-frequency seed laser module and the like. The amplifying module 2 may include but not limited to a broadband amplifying module and the like. The conversion module 4 may include but not limited to a frequency conversion module and the like. The optical fiber 3 may include but not limited to an energy transmission optical fiber and the like.

According to some embodiments of the present disclosure, the seed laser module 1 can output single-frequency lasers with at least two wavelengths based on one seed laser; or output single-frequency lasers with at least two wavelengths based on different seed lasers. The outputting lasers of at least two wavelengths based on different seed lasers specifically includes: combining outputs of different seed lasers by beam combining technology, and then outputting lasers of at least two wavelengths. The seed laser may be a single-frequency laser, including but not limited to fiber seed laser, semiconductor seed laser or other solid-state lasers. For example, the seed laser may include a pump laser, a pump optical coupler, a distributed feedback fiber Bragg grating, and the like. The output of the seed laser may comprise different wavelengths in the same radiation band, or different wavelengths in different radiation bands.

According to some embodiments of the present disclosure, the amplification module 2 may include an amplifier, which may be a fiber amplifier based on rare earth ion gain, including but not limited to ytterbium-doped fiber amplifiers, erbium-doped fiber amplifiers, thulium-doped fiber amplifiers, etc.; Or it can be a fiber amplifier based on nonlinear effects, including but not limited to a Raman fiber amplifier; or it can be a single-stage amplifier, or it can be a multi-stage amplifier. For example, the amplifier may include a pump source, a gain fiber, a pump signal combiner, a pump light filter, an isolator, and the like. Determine whether lasers of different wavelengths are covered based on the bandwidth of the amplifier, if so, amplify the lasers of at least two wavelengths through the amplifier; if not, amplify the lasers of at least two wavelengths respectively through at least two amplifiers in parallel, and Bundling is performed by combining beams. The beam combining manner may include wavelength division multiplexing beam combining, polarization beam combining, and the like.

In some embodiments, for the seed laser of one wavelength, the target power can be achieved through a single-stage amplifier; when the single-stage amplifier cannot meet the requirements, the power of the seed laser of this wavelength can be amplified to the target power by cascading multi-stage amplifiers.

In some embodiments, for the seed laser light of at least two wavelengths, when the bandwidth of one amplifier covers the at least two wavelengths, one amplifier is used to amplify the power; if one amplifier cannot be realized, at least two amplifiers can be used to amplify the power respectively The seed laser light of the at least two wavelengths reaches a target power.

According to some embodiments of the present disclosure, the conversion module 4 may apply an optical frequency conversion technology based on nonlinear effects. The conversion module 4 may include a mode matching lens, a temperature control module, a nonlinear crystal, a beam splitter, a collimator lens and the like. The frequency conversion performed by the conversion module may apply related technologies, including one or a combination of sum frequency process, difference frequency process and frequency multiplication process. The conversion module can use a nonlinear crystal to achieve frequency conversion, and determine whether to cover lasers of different wavelengths based on the coverage bandwidth of the crystal. If so, realize frequency conversion through one crystal; if not, realize frequency conversion through cascading multiple crystals. In some embodiments, the laser light output by the amplifying module may pass through multiple crystals in sequence, and the crystals of different periods may not have a sequence in the optical path. As an example, each crystal can cooperate with independent temperature control to realize a multi-wavelength nonlinear frequency conversion process. The nonlinear crystals include but not limited to bulk crystals, waveguides and the like. In some embodiments, by selecting a suitable fundamental frequency light and a nonlinear frequency conversion method, laser light of any wavelength band can be generated.

Embodiment one

Fig. 2 is an exemplary schematic diagram of a multi-band single-frequency laser output system according to Embodiment 1 of the present disclosure. As shown in Figure 2, according to some embodiments of the present disclosure, 1-1 of the seed laser module 1 is two cascaded distributed feedback fiber Bragg gratings, which can be set to radiate 10mw 1909.4861nm and 15mw 1985.6964nm single-frequency seeds Laser: 1-2 of the seed laser module 1 is a distributed feedback fiber Bragg grating, which can be set to radiate 10mw 1080nm single-frequency seed laser. The 1080nm and 1909.4861nm/1985.6964nm single-frequency seed lasers of different wavelength bands are respectively injected into the amplifier 2-1 and the amplifier 2-2 of the amplification module 2. Amplify the 10mw 1080nm single-frequency seed laser in the amplifier 2-1 (for example, ytterbium-doped fiber amplifier), and the amplified power is 6w; put the 10mw 1909.4861nm and 15mw 1985.6964nm single-frequency seed laser in the amplifier 2- 2 (for example, thulium-doped fiber amplifier) for mixed wavelength amplification, the amplified power is 5w. 1080nm and 1909.4861nm/1985.6964nm are coupled into the same optical fiber 3 through a beam combiner and injected into the conversion module 4 . In the first crystal 4-1, the sum-frequency conversion is realized. Among them, the sum frequency of 1080nm and 1909.4861nm produces 689.8326nm, and the power is about 2w; the sum frequency of 1080nm and 1985.6964nm produces 699.5318nm, and the power is about 2w. Further, frequency doubling conversion of 689.8326nm and 699.5318nm is realized in the second crystal 4-2 to generate 344.9163nm and 349.7659nm single-frequency lasers of 100 milliwatts. In summary, a single laser system can achieve two-band single-frequency laser output by sharing the seed laser, shared amplifier, and shared nonlinear frequency conversion, and the whole system is simpler and more reliable.

As an example, Embodiment 1 may specifically include that the same laser simultaneously outputs lasers with two wavelengths of 344.9163nm and 349.7659nm, and it is set that the lasers cool OH molecules.

Embodiment two

Fig. 3 is an exemplary schematic diagram of a multi-band single-frequency laser output system according to Embodiment 2 of the present disclosure. As shown in Figure 3, according to some embodiments of the present disclosure, 1-1 of the seed laser module 1 is two cascaded distributed feedback fiber Bragg gratings, which can be set to radiate 10mw 1545.827nm and 10mw 1545.755nm single-frequency seeds Laser: 1-2 of the seed laser module 1 is a distributed feedback fiber Bragg grating, which can be set to radiate 10mw 1900nm single-frequency seed laser. The 1900nm and 1545.827nm/1545.755nm single-frequency seed lasers of different wavelength bands are respectively injected into the amplifier 2-1 and the amplifier 2-2 of the amplification module 2 . The 1900nm single-frequency seed laser of 10mw is amplified in amplifier 2-1 (for example, thulium-doped fiber amplifier), and the power after amplification is 5w; For example, an erbium-doped fiber amplifier) performs mixed wavelength amplification, and the amplified power is 5w. 1900nm and 1545.827nm/1545.755nm are coupled into the same optical fiber 3 through a beam combiner and injected into the conversion module 4 . The sum frequency conversion is realized in the conversion module 4, wherein, the sum frequency of 1900m and 1545.827nm produces 852.356nm, and the power is about 2w; the sum frequency of 1900nm and 1545.755nm produces 852.334nm, and the power is about 2w. As an example, dual wavelengths of 852.356nm and 852.334nm can be set as a cooling follow-back pump for cesium atoms.

Embodiment Three

Fig. 4 is an exemplary schematic diagram of a multi-band single-frequency laser output system according to Embodiment 3 of the present disclosure. As shown in FIG. 4 , according to some embodiments of the present disclosure, 1-1 in the figure can generate two single-frequency seed lasers of 10mw 1560nm and 15mw 1550nm, and 1-2 can generate 20mw 1064nm single-frequency seed laser. The gain fiber of the laser module 2 is an erbium-ytterbium co-doped gain fiber, and the erbium-ytterbium co-doped gain fiber can provide gains for 1064nm, 1550nm, and 1560nm three bands, and the length of the gain fiber can be reasonably controlled, so that the lasers of the three bands can be They are all amplified to the watt level; then, they are injected into the nonlinear frequency conversion module 4 through the optical fiber 3, and a difference frequency crystal is designed in the conversion module 4, and a difference frequency process occurs, wherein the difference frequency of 1064nm laser and 1550nm laser can generate 3393.416nm laser ; 1064nm laser and 1560nm laser can generate 3346.452nm laser by difference frequency. In the third embodiment, one system can simultaneously generate single-frequency lasers in two bands.

It should be noted that the above description of the multi-band single-frequency laser output system is only for convenience of description, and does not limit the present disclosure to the scope of the illustrated embodiments. It can be understood that, for those skilled in the art, based on the principle of the device, without departing from the principle, any combination of each structure may be made, or sub-structures may be combined with other structures to implement the functions of the above-mentioned devices and operations. Various corrections and changes in form and detail have been made. For example, the multi-band single-frequency laser output system may include realizing multi-band single-frequency laser output below 1000 nm and/or above 2000 nm. Such modifications are within the protection scope of the present disclosure.

To sum up, the multi-band single-frequency laser output system of the present disclosure constructs a multi-band single-frequency laser output system by connecting the seed laser module, amplification module, conversion module, etc. through an optical fiber, and utilizes multiple seed lasers to generate, inject, and multi-band amplify, Multi-band frequency conversion and other technical means enable a laser system to output multiple bands of single-frequency laser.

It should be noted that the above-mentioned embodiments are only used as examples, and the present disclosure is not limited to such examples, but various changes can be made.

Claims

A multi-band single-frequency laser output system, including:

A seed laser module, the seed laser module is configured to output a single-frequency laser with at least two wavelengths;

an amplifying module, the amplifying module is configured to increase the power of each wavelength laser;

A conversion module, the conversion module is configured to perform nonlinear frequency conversion on the amplified laser wavelength.
The system according to claim 1, wherein the seed laser module outputs single-frequency lasers with at least two wavelengths based on one seed laser; or outputs single-frequency lasers with at least two wavelengths based on different seed lasers.
The system according to claim 2, wherein said outputting lasers of at least two wavelengths based on different seed lasers specifically comprises: combining outputs of different seed lasers using beam combining technology, and then outputting lasers of at least two wavelengths.
The system according to claim 2, wherein the seed laser is a single-frequency laser, including a fiber seed laser, a semiconductor seed laser, and a solid-state laser.
The system according to claim 1, wherein the amplifier is a fiber amplifier based on rare earth ion gain, including an ytterbium-doped fiber amplifier, an erbium-doped fiber amplifier, and a thulium-doped fiber amplifier; or a fiber amplifier based on nonlinear effects, including Raman fiber amplifier; or a single-stage amplifier, or a multi-stage amplifier.
The system according to claim 5, wherein it is determined based on the bandwidth of the amplifier whether to cover laser light of different wavelengths, if so, amplify the laser light of at least two wavelengths through the amplifier; if not, at least two of the amplifiers in parallel , separately amplify the laser light of at least two wavelengths, and combine the beams through beam combining technology, the beam combining methods include wavelength division multiplexing beam combining and polarization beam combining.
The system of claim 1, wherein the transformation module applies a non-linear effect based optical frequency transformation technique.
The system according to claim 7, wherein the frequency conversion performed by the conversion module includes one or a combination of sum frequency process, difference frequency process and frequency multiplication process.
The system according to claim 7, wherein the conversion module uses a nonlinear crystal to realize frequency conversion, and determines whether to cover lasers of different wavelengths based on the coverage bandwidth of the crystal, and if so, realizes frequency conversion through a crystal; if not, The frequency conversion is realized by cascading multiple crystals; the nonlinear crystal at least includes a block crystal and a waveguide.
The system according to any one of claims 1-9, wherein laser light of any wavelength band is generated by selecting an appropriate fundamental frequency light and a nonlinear frequency conversion method.