CN110676683B

CN110676683B - Acousto-optic electromechanical linkage multi-wavelength tunable synchronous light source

Info

Publication number: CN110676683B
Application number: CN201910982331.2A
Authority: CN
Inventors: 曾和平; 杨康文; 沈悦
Original assignee: East China Normal University; Chongqing Institute of East China Normal University; University of Shanghai for Science and Technology
Current assignee: East China Normal University; Chongqing Institute of East China Normal University; University of Shanghai for Science and Technology
Priority date: 2019-10-16
Filing date: 2019-10-16
Publication date: 2021-04-16
Anticipated expiration: 2039-10-16
Also published as: CN110676683A

Abstract

The invention discloses an acousto-optic electromechanical linkage multi-wavelength tunable synchronous light source, which comprises a reflecting element, a dispersion element, an optical switch, a gain medium, an output coupler, a mode locking device, a pumping source, a wavelength division multiplexer, a polarization controller, different types of optical switches, different types of parametric media, a 2 x 1 beam combiner and delay modules on different branches, wherein the reflecting element, the dispersion element, the optical switch, the gain medium, the output coupler and the mode locking device are sequentially arranged along a light path. The pump light resonant cavity is composed of a reflecting element, a solid medium can be used as a gain medium in the cavity, and a pump source is additionally arranged to enable the cavity to be excited and radiated to generate laser with specific wavelength. The optical switch is added in the cavity to realize the switching of different optical paths, and the stable multi-wavelength pulse is output by combining the frequency conversion effect generated by the nonlinear action in different parametric media, and finally the acousto-optic electromechanical linkage multi-wavelength tunable synchronous light source is realized.

Description

Acousto-optic electromechanical linkage multi-wavelength tunable synchronous light source

Technical Field

The invention belongs to the technical field of ultrafast optics and laser, and particularly relates to an acousto-optic electromechanical linkage multi-wavelength tunable synchronous light source.

Background

With the development of science and technology, people have more and more extensive application of laser, so that the production and life of people are changed by the laser, and the development of various fields of national economy is promoted. In many fields of laser technology, multi-wavelength laser has the advantage of simultaneously outputting multiple wavelengths, can be used in the fields of terahertz generation, biological imaging and the like, has the advantages that single-wavelength laser does not have, and is an important direction for laser development all the time. The single-wavelength laser only has single-energy photons, and can not meet the requirements of some practical applications and scientific and technological development, so that the single-wavelength laser is limited to be realized only by combining lasers with different wavelengths, and has more related instruments in practical use, complex and complicated operation and is not beneficial to popularization and use.

The limitation of the realization of the multi-wavelength tunable light source is that the method for realizing the tunable multi-wavelength is that the multi-wavelength is directly adjusted in the oscillator, which easily causes the unlocking of the mode-locked laser, and the tunable wavelength range is limited by the gain bandwidth of the gain medium, and the tunable range is not large. In the early stage, the tunable multi-wavelength of the laser is realized mainly by adding wavelength tunable elements such as an F-P cavity, a dielectric film filter, an acousto-optic filter and the like into a resonant cavity of the laser. These free-space tuning devices are typically non-fiber structures with large insertion losses that reduce the efficiency, integration, and compactness of the laser. Recently, people adopt all-fiber filters to replace space tuners, so that loss can be effectively reduced, and integration is facilitated. However, the tunable fiber grating represented by the long-period fiber grating is relatively expensive to manufacture, and is limited by the strain characteristics of the fiber grating itself, and the wavelength tuning range is small.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the acousto-optic electromechanical linkage multi-wavelength tunable synchronous light source which has the advantages of compact structure, stable performance, rich wavelengths, continuous tuning and capability of simultaneously exciting multiple energy photons.

In order to achieve the purpose, the invention adopts the following technical scheme:

an acousto-optic electromechanical linkage multi-wavelength tunable synchronous light source is characterized in that the light source is sequentially provided with a reflection element, a dispersion element, a first optical switch, a gain medium, a first output coupler, a mode locking device and a pumping source which acts on the gain medium independently along a light path, seed light is output by the first output coupler, sequentially enters the wavelength division multiplexer, a second output coupler, a polarization controller and a second optical switch along the light path, and is divided into two branches by the second optical switch, the first branch sequentially enters a first parameter medium along the light path, is divided into two delay loops by a third optical switch, and respectively passes through the first delay device and the second delay device, and the two delay loops return to the wavelength division multiplexer on the light path through a first beam combiner to form an annular loop cavity; the second branch circuit gets into second parameter medium, rethread fourth photoswitch along the light path in proper order and falls into two delay circuit, respectively through third delay unit, fourth delay unit, and two delay circuit get back to the wavelength division multiplexer that gets into on a light path again through the second beam combiner, form another annular circuit chamber, wherein:

the reflection element, the dispersion element, the first optical switch, the gain medium, the mode locking device, the first output coupler and the pumping source jointly form a main resonant cavity to output seed pulses, the light generates dispersion through the dispersion element and is combined with the first optical switch to realize small-range continuous tuning in the cavity, the gain medium is used as a working substance for providing energy level transition, and the energy is provided for the working substance through the pumping source to realize population inversion and generate stimulated radiation; adding a mode locking device to enable the laser to generate ultrashort pulses, and finally outputting seed light by a first output coupler;

the wavelength division multiplexer is used for converging the multiple paths of light paths into one path of light path, and seed light generated by the main resonant cavity passes through the wavelength division multiplexer and forms a loop with the second output coupler, the polarization controller, the second optical switch, the first parameter medium, the third optical switch, the first delay device and the first beam combiner respectively; and the second output coupler, the polarization controller, the second optical switch, the first parametric medium, the third optical switch, the second time delay device and the first beam combiner form another loop; then the second output coupler, the polarization controller, the second optical switch, the second parametric medium, the fourth optical switch, the third time delay device and the second beam combiner form a loop; the optical fiber coupler, the polarization controller, the second optical switch, the second parametric medium, the fourth optical switch, the fourth time delay device and the second beam combiner form a last loop, and four optical annular loops are formed;

the second output coupler is used for forming a loop of the parametric resonant cavity and realizing multi-wavelength tunable pulse output;

a polarization controller for adjusting the polarization state of light to satisfy the condition of different four-wave mixing occurring in the gain medium;

the second optical switch is used for forming different optical paths and can switch different parametric resonant cavities by controlling the optical switch;

the first parametric medium and the second parametric medium which are high nonlinear substances are respectively arranged on two branches divided by the second optical switch, and the light generates nonlinear action in the first parametric medium and the second parametric medium to expand the spectrum;

the third optical switch and the fourth optical switch are used for switching different time delay devices to form four loops;

a first delay device, a second delay device, a third delay device and a fourth delay device are respectively arranged in four loops formed by a third optical switch and a fourth optical switch and used for realizing the functions of optical parametric amplification and narrowing filtering, and the continuous tuning output of optical pulses is realized by moving the position of a mechanical translation stage in the delay devices and changing the cavity length;

and the first beam combiner and the second beam combiner are used for combining the light paths and forming a closed loop with the wavelength division multiplexer.

The first optical switch, the second optical switch, the third optical switch and the fourth optical switch can adopt mechanical optical switches, acousto-optic switches or electro-optic switches, selection can be carried out by combining different requirements, a plurality of optical paths can be formed by adding the optical switches in the optical paths, and the optical switches are used for switching different optical paths so as to output pulses with different wavelengths.

The first parameter medium and the second parameter medium are solid nonlinear media such as lithium niobate crystals or photonic crystal fibers, and nonlinear effects are generated between the first parameter medium and the second parameter medium and the input seed pulse by utilizing the nonlinear characteristics of the first parameter medium and the second parameter medium, so that the spectrum is expanded, and the effect of switching the optical path by the optical switch is combined to realize the output of the multi-wavelength synchronous light source.

The first time delay device, the second time delay device, the third time delay device and the fourth time delay device adopt different structures to match with corresponding lengths, and change the length of the resonant cavity through moving the position, so that the optical parametric amplification and narrowing filtering effects are realized, and the continuous tuning output of optical pulses is realized.

The invention can realize free switching of a plurality of optical paths by flexibly using the optical switch in the resonant cavity, for example, by using a mechanical optical switch, and can realize the function of fixed-point tuning wavelength in a small range by using different types of fiber Bragg gratings in different optical paths in the optical fiber optical path. Multi-wavelength tuning can also be achieved using acousto-optic switches, where the refractive index of the medium changes periodically with the acoustic wave action, forming an optical "phase grating" where the grating pitch is equal to the acoustic wavelength. When light waves pass through the medium, diffraction of the light occurs. The intensity, frequency, direction and the like of the diffracted light can be changed by controlling the ultrasonic field, and the grating is added after the acousto-optic modulation crystal to realize the continuous tuning of the wavelength. The electro-optical switch is used for realizing the light path conversion, the electro-optical effect or the electric absorption effect of the crystal material is used for changing the refractive index of the material and the phase of light under the action of an electric field, and then the interference or the polarization of the light is used for changing the light intensity or the light path conversion to switch different light paths, so that different resonant cavity loops are formed, and the wavelength which can be realized is expanded.

In the invention, various optical switches are combined to realize the resonance of a plurality of optical paths, the wave band of an output light source of the whole resonant cavity is expanded, and high-nonlinearity optical fibers are combined and used, and the nonlinear effect generated by the high-nonlinearity optical fibers, such as a four-wave mixing effect, breaks the limitation of a gain medium band and can realize the conversion to light with lower frequency or higher frequency. The optical switch controls that different light paths are respectively provided with a section of gain optical fiber, and multicolor synchronous lasers with different wavelengths, different gain coefficients and different output powers can be realized by flexibly selecting the types of the gain optical fibers (such as optical fibers doped with ytterbium, erbium, thulium, holmium and other elements), the lengths of the gain optical fibers and the doping concentrations of the gain optical fibers. Meanwhile, the structure of the non-shared gain optical fiber can inhibit the unfavorable nonlinear effects of gain narrowing, amplified spontaneous radiation, gain competition and the like, and improve the stability of output power. Meanwhile, the optical parameter is amplified and narrowed by combining a time delay device, and the continuous tuning effect is realized.

The invention has the beneficial effects that:

1. the invention adopts an integrated structure, utilizes the optical switch, overcomes the limitation that a plurality of lasers are needed to realize different wavelengths in actual use, and can directly output wide-range multi-wavelength tunable laser pulses.

2. The invention flexibly uses the optical switch, combines the cavity structure of the resonant cavity, utilizes the advantages of various optical switches, can form a plurality of optical paths, and forms the light source with compact structure, small loss and strong controllability.

3. The invention can adopt an all-fiber structure, can greatly reduce the volume of a laser light source, is convenient to integrate the whole light path into a very small space, improves the stability and is suitable for being used in complex environments except ultra-clean laboratories.

4. The invention realizes the precise synchronization of multi-channel ultrashort pulse based on the nonlinear ultrafast modulation action in the gain medium in the resonant cavity, the response speed of the nonlinear effect is very fast, the order of picosecond or even femtosecond is reached, the synchronization precision can be greatly improved, and the high-precision synchronous pulse which is several orders of magnitude higher than the prior electronic circuit synchronization mode is realized.

5. The invention utilizes the nonlinear function which can be generated in different types of gain media used on different light paths to obtain the conversion of large-range frequency pulses, and then combines with an optical switch to switch different resonance branches to realize the selection of multi-range wavelength pulses.

6. The invention adopts the optical switch control mode to switch different optical switches to realize different optical path resonances, can operate independently and is not interfered by other branches, thereby ensuring the long-term stable operation of each branch resonant cavity and further improving the stability of the whole system.

7. The invention combines the cavity structure of the optical parametric oscillation cavity and the time delay device to obtain the continuously tuned spectrum output.

8. The gain media of each branch in the resonant cavity are independent, and multi-channel pulse laser output with multiple wave bands and multiple parameters can be realized by adopting different types of gain media.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of an implementation of a different type of optical switch;

FIG. 3 is a schematic illustration of the effect of nonlinear effects produced using highly nonlinear fibers;

FIG. 4 is a schematic view of the spatial structure of the present invention;

FIG. 5 is a schematic view of an optical fiber structure according to the present invention;

FIG. 6 is a schematic diagram of a standing wave type parametric resonator according to the present invention.

Detailed Description

The features of the present invention and other related features are described in further detail below by way of example with reference to the accompanying drawings.

Referring to fig. 1, the present invention includes a reflective element 1, a dispersive element 2, a first optical switch 3, a gain medium 4, a mode locking device 5, a first output coupler 6, a pump source 7, a wavelength division multiplexer 8, a second output coupler 9, a polarization controller 10, a second optical switch 11, a third optical switch 14, a fourth optical switch 18, a first parametric medium 12, a second parametric medium 13, a 2 × 1 combiner 17, a 2 × 1 combiner 21 of different types, and delay devices on different branches, including a first delay device 15, a second delay device 16, a third delay device 19, and a fourth delay device 20. The pump light resonant cavity is a standing wave type resonant cavity formed by two elements with reflection property, and uses titanium sapphire crystal or rare ion doped optical fiber as gain medium, and adds pump source to implement intracavity stimulated radiation to produce light with specific wavelength, and in the cavity an optical switch is added, and can change optical path, for example, the mechanical optical switch is combined with grating to implement fixed-point tuning of light pulse with different wavelengths, or a dispersion element is added to make the light in the cavity produce dispersion to separate light with different wavelengths, and then the optical switch is combined to implement continuous tuning of seed light with different wavelengths, and the mode-locking device in the cavity is used for auxiliary laser self-mode-locking to implement output a series of continuous stable pulse series, and the commonly-used elements can be saturated absorber, etc. After a stable pulse is formed in the cavity, a first output coupler 6 outputs the stable pulse as seed light, a light path is divided into two branches by a wavelength division multiplexer 8, a second output coupler 9, a polarization controller 10 and a second optical switch 11 (an electro-optical switch, an acousto-optical switch and the like), the two branches pass through different first parametric media 12 and second parametric media 13 respectively, the branch passing through the first parametric media 12 passes through a third optical switch 14 and is divided into two branches, the two branches pass through a first delay device 15 and a second delay device 16 respectively, then a beam combiner 17 and the wavelength division multiplexer 8 form a closed loop, the other branch passing through the second parametric media 13 passes through a fourth optical switch 18 and is divided into two branches again, the two branches pass through a third delay device 19 and a fourth delay device 20 respectively, and then a beam combiner 21 and the wavelength division multiplexer 8 form a closed loop, finally, three optical switches (a second optical switch, a third optical switch and a fourth optical switch) form four different parametric oscillation loop cavities. The polarization controller 10 may be added according to an experimental scheme, and the polarization controller 10 is to modulate the polarization state of the seed light in the input parametric resonator, so that different conditions required for scalar four-wave mixing and vector four-wave mixing with a gain medium, such as a photonic crystal fiber, are realized. Different types of parametric media used on different branches, such as lithium niobate crystals or photonic crystal fibers, realize spectrum expansion by utilizing the strong nonlinear properties of the media. And finally, four parametric oscillators with annular structures are formed by using a 2X 1 beam combiner and a wavelength division multiplexer.

All the devices and the connection thereof can be built by optical fiber light paths and can adopt polarization maintaining optical fibers.

The optical switch can be a mechanical optical switch, an acousto-optic switch, an electro-optic switch and other devices, and the change of the optical path is realized by adjusting the optical switch to form the resonance of different optical paths.

The dispersion element 2 can adopt a prism to realize the dispersion of light and separate the light with different wavelengths.

The mode locking device 5 can be a saturable absorber, and the self-mode locking of the laser is realized.

The parametric medium can adopt a high nonlinear medium, such as lithium niobate crystals and the like or photonic crystal fibers, the frequency range of light is expanded by utilizing the nonlinear effect generated in the medium, and multi-wavelength tuning is realized by combining a delay module.

The output coupler 9 may be an optical fiber coupler with an output ratio of 1:9 or 5:95, or a coupler formed by coating a coated lens made of a material allowing a reflectance of 5% to light and a transmittance of 95%.

The polarization modulator 10 may adopt a half-wave plate, and the polarization state of light is changed by rotating the wave plate.

The time delay device can realize the functions of optical parametric amplification and narrowing filtering by utilizing a single-mode optical fiber and an electric translation stage, and realizes the continuous tuning output of optical pulses by moving the translation stage.

Fig. 2 is a schematic diagram of various types of optical switches, wherein, as shown in fig. 2a, a mechanical optical switch may be used in an optical fiber path to combine with a bragg fiber grating, and a rotary mechanical optical switch may change the optical path to combine with grating devices on different branches to implement switching of fixed wavelengths. Or, as shown in fig. 2b, an electro-optical switch is adopted, the electro-optical effect or the electric absorption effect of the dielectric material is utilized, the refractive index of the material and the phase of light are changed under the action of an electric field, then the light intensity is suddenly changed or the light path is changed by utilizing the interference, the polarization and the like of the light, the grating is combined to realize continuous tuning, and the reflecting mirror is added behind to enable the light to oscillate back and forth in the cavity. As shown in fig. 2c, an acousto-optic switch may be further employed, and an acousto-optic effect of a material is utilized, so that the material generates mechanical strain, and a refractive index of the material is periodically changed to form a bragg grating, so that input light is diffracted, output light is subjected to a dispersion action through a triple prism, an optical pulse is broadened, and a reflective device is reused to form an oscillation cavity. Various optical switches can be selected according to actual requirements, the acousto-optic switches can be continuously adjustable, the electro-optic switches can be controlled at high speed, and the mechanical switches can meet the requirement of low loss.

Fig. 3 is a schematic diagram of the effect of the nonlinear effect generated by using the high nonlinear fiber, and the optical nonlinear effect, i.e., four-wave mixing, self-phase modulation, etc., can generate signal light with a fixed frequency difference, thereby providing an idea for spectrum expansion. In the optical fiber, four-wave mixing is used as a special nonlinear effect of light, and three photons act together to generate a fourth photon so as to realize frequency conversion. For example, by using the photonic crystal fiber, four-wave mixing effects in different conversion processes can be obtained by controlling the included angle between the polarization angle of the seed light and the fast and slow axes of the fiber, and the spectrum can be expanded in a wider range. When seed light with a fixed wavelength passes through the photonic crystal fiber, scalar four-wave mixing can be generated when incident light of the seed light is parallel to the fast axis or the slow axis of the photonic crystal fiber, and two photons can be generated at the moment and respectively used as signal light and idler frequency light. When the included angle of the incident light and the fast axis or the slow axis of the photonic crystal fiber is 45 degrees, the cross phase modulation is unstable, and two photons with different frequencies are generated. The phase matching condition indicates that the four-wave mixing effect generated by different incident pump light is different, thereby generating signal light and idler light with different wavelengths. And when the wavelength of the pump light is in a certain range, five sidebands can be generated in the photonic crystal fiber at the same time, wherein two sidebands are from scalar four-wave mixing, and three sidebands are from cross-phase modulation instability, namely vector four-wave mixing. Gain optical fibers with different parameters can be adopted, and signal light with different wave bands can be obtained.

Example 1

Fig. 4 is a schematic diagram of a spatial structure of the present invention, in which two mirrors are used, the reflectivity of each mirror reaches 98%, and the two mirrors are used as a reflective element 1 to form a standing wave resonant cavity, and a solid nonlinear medium is used as a gain medium 4, and a pumping source 7 is provided from the outside, so that the gain medium 4 is excited to emit photons, and the photons oscillate in the resonant cavity. The first optical switch 3 is added in the main cavity, the optical output angle is deflected through the adjusting switch, light with multiple wavelengths is generated through the dispersion effect of the grating 2, light pulses with specific wavelengths are reflected by the reflecting mirror through the adjusting light path and oscillate back and forth in the resonant cavity, the gain and the loss are balanced, and the light pulses are used as the first output coupler 6 through the dichroic mirror to form stable output. The optical pulse output by the main resonant cavity passes through the dichroic mirror as a second output coupler 9, passes through a second optical switch 11, can switch two optical paths by adjusting the switch, respectively forms two optical paths through a first reflector I and a second reflector II, and respectively uses a first parameter medium 12 and a second parameter medium 13 of different types on the two optical paths, the seed light passes through the gain medium, due to the nonlinear effect of the light in the medium, the spectrum broadening is caused, and the selection of more spectra is realized. Two light paths passing through different parameter media respectively pass through a third optical switch 14 and a fourth optical switch 18, light path switching is realized by the optical switches, and then four branch paths are respectively formed by combining a plurality of reflectors and dichroic mirrors with specific parameters, wherein the third reflector III forms a branch path I, the fourth reflector IV forms a branch path II, and one dichroic mirror and one reflector are used as a beam combiner 21, wherein the dichroic mirror can realize light of a wave band generated by a resonant cavity of the branch path I and reflect light of a wave band generated by the resonant cavity of the branch path II. The fifth reflector V forms a branch and the sixth reflector VI forms a branch, and then the beam combiner 17 is composed of a dichroic mirror and reflectors, wherein the dichroic mirror can realize the light of the wave band generated by the transmission branch and the resonant cavity, and the reflection branch and the resonant cavity.

Different delay elements

15, 16, 19 and 20 are added in the four formed annular loops to serve as delay devices, so that the amplification and narrowing of optical parameters are realized respectively, and tunable multi-wavelength pulses can be output by adjusting delay positions. And then a complete closed loop is formed by using the reflecting mirror and the dichroic mirror as a wavelength division multiplexer 8, and finally the multi-wavelength tunable pulse is output by using the dichroic mirror as a second output coupler 9.

Example 2

Fig. 5 is a schematic structural diagram of an optical fiber device according to the present invention, in which a bragg fiber grating with multiple central wavelengths is used as a reflective element, and a pulse with a specific central wavelength can be selected by the bragg fiber grating, so that a pulse with a stable wavelength is output from a cavity, a first optical switch 3 is included in a main optical path, and an optical switch switches an optical path to be combined with different bragg fiber gratings, so as to realize a fixed-point wavelength adjustment, a Yb-doped gain fiber is used as a gain medium 4, a saturable absorber is used as a mode locking device 5 and forms a resonant cavity together with the bragg fiber grating, wherein a photodiode is used as a pump source 7, a fiber coupler is used as a first output coupler 6, so as to output a stable seed pulse, which is then divided into two branches by a wavelength division multiplexer 8, a second output coupler 9, a polarization controller 10, and a second optical switch 11, the two branches are respectively provided with parametric media 12 and 13 with different parameters, the photonic crystal fiber PCF can be used for realizing spectrum broadening, and the polarization modulator 10 is used for tuning the polarization of the seed light input into the photonic crystal fiber, so that the angle between the seed light and the fast axis or the slow axis of the photonic crystal fiber can be changed, different requirements of scalar four-wave mixing or vector four-wave mixing are realized, and a wider adjustable spectrum range is obtained. And then, a third optical switch 14 and a fourth optical switch 18 are used for respectively forming two branches, each branch is added with a

delay device

15, 16, 19 and 20, the delay devices can be formed by a single-mode polarization-maintaining optical fiber and an optical fiber translation stage, the narrowing filtering of optical parameters and the amplification of a parametric oscillator are realized by adjusting the translation stage, and four annular loops are formed in total. Finally, a closed ring cavity is formed by the

combiners

17 and 21, respectively. The device in the light path all uses the optical fiber structure, relies on the optical fiber to connect the light path, integrates higher, makes the light path loss littleer by the optical fiber butt fusion, and the core thought of structure relies on photoswitch to realize the purpose of switching different resonant cavities, combines the output that the nonlinear effect realized the tunable synchronous light source of multi-wavelength.

Example 3

Fig. 6 is a schematic structural diagram of another embodiment of the present invention, which shows a schematic cavity diagram of a parametric resonator using a standing wave cavity, and demonstrates the diversity and expansibility of the present invention. The parametric resonant cavity is mainly a standing wave cavity structure formed by semi-transmitting and

semi-reflecting elements

22 and 23 and reflecting

elements

24 and 25 which transmit seed light and can reflect signal light in the resonant cavity. The parametric cavity includes a second output coupler 9 which is capable of outputting a proportional pulse while maintaining oscillation of the cavity. And the two branches can use different first parametric media and second parametric media, respectively utilize different nonlinear effects to realize spectrum expansion, and then control and switch

different delay devices

15, 16, 19 and 20 through a third optical switch 14 and a fourth optical switch 18, and finally combine two delay devices into the same parametric resonant cavity through

beam combiners

17 and 21. The whole device mainly changes the light path by means of various types of

optical switches

3, 11, 14 and 18 to realize different light path switching, combines

parameter media

12 and 13 with different parameters to realize the purpose of expanding the output spectrum by utilizing the nonlinear action of the parameter media, and finally outputs multi-wavelength tunable pulses through the second output coupler 9 to provide the acousto-optic electromechanical linkage multi-wavelength tunable synchronous light source.

Claims

1. The acousto-optic electromechanical linkage multi-wavelength tunable synchronous light source is characterized in that the light source is sequentially provided with a reflecting element (1), a dispersion element (2), a first optical switch (3), a gain medium (4), a first output coupler (6), a mode locking device (5) and a pumping source (7) which acts on the gain medium (4) independently along a light path, seed light is output by the first output coupler (6), enters a wavelength division multiplexer (8), a second output coupler (9), a polarization controller (10) and a second optical switch (11) along the light path in sequence, and is divided into two branches by the second optical switch (11), the first branch enters a first parameter medium (12) along the light path in sequence and is divided into two delay loops through a third optical switch (14), and the two delay loops pass through a first delay device (15) and a second delay device (16) respectively, and return to the same light path through a first beam combiner (17) 8) Forming an annular loop cavity; the second branch circuit gets into second parameter medium (13), rethread fourth photoswitch (18) in proper order along the light path and divides into two delay circuit, passes through third delay unit (19), fourth delay unit (20) respectively, and two delay circuit get back to and get into wavelength division multiplexer (8) on a light path again through second beam combiner (21), form another annular circuit chamber, wherein:

the reflection element (1), the dispersion element (2), the first optical switch (3), the gain medium (4), the mode locking device (5), the first output coupler (6) and the pumping source (7) jointly form a main resonant cavity to output seed pulses, dispersion is generated by the dispersion element (2) and is combined with the first optical switch (3) to realize continuous tuning of the range in the cavity, the gain medium (4) is used as a working substance for providing energy level transition, and energy is provided for the working substance by the pumping source (7) to realize population inversion and generate stimulated radiation; a mode locking device (5) is added to enable the laser to generate ultrashort pulses, and finally seed light is output by a first output coupler (6);

the wavelength division multiplexer (8) is used for converging a plurality of paths of light paths into one path of light path, and seed light generated by the main resonant cavity passes through the wavelength division multiplexer and forms a loop with the second output coupler (9), the polarization controller (10), the second optical switch (11), the first parameter medium (12), the third optical switch (14), the first time delay device (15) and the first beam combiner (17) respectively; and the second output coupler (9), the polarization controller (10), the second optical switch (11), the first parametric medium (12), the third optical switch (14), the second delay device (16) and the first beam combiner (17) form another loop; then the optical fiber is combined with a second output coupler (9), a polarization controller (10), a second optical switch (11), a second parametric medium (13), a fourth optical switch (18), a third time delay device (19) and a second beam combiner (21) to form a loop; the optical fiber coupler also forms a last loop with a second output coupler (9), a polarization controller (10), a second optical switch (11), a second parametric medium (13), a fourth optical switch (18), a fourth time delay device (20) and a second beam combiner (21), and four optical annular loops are formed;

the second output coupler (9) is used for forming a loop of the parametric resonant cavity and realizing multi-wavelength tunable pulse output;

a polarization controller (10) for adjusting the polarization state of the light to meet the condition that different four-wave mixing occurs in the gain medium;

the second optical switch (11) is used for forming different optical paths and switching different parametric resonant cavities by controlling the second optical switch;

a first parametric medium (12) and a second parametric medium (13) which are solid nonlinear media are respectively arranged on two branches divided by a second optical switch (11), and light is utilized to generate nonlinear action in the solid nonlinear media to expand the spectrum;

a third optical switch (14) and a fourth optical switch (18) for switching different delay devices to form four loops;

a first delay device (15), a second delay device (16), a third delay device (19) and a fourth delay device (20) are respectively arranged in four loops formed by a third optical switch and a fourth optical switch and used for realizing the functions of optical parametric amplification and narrowing filtering, and the cavity length is changed by moving the position of a mechanical translation stage in the delay devices so as to realize continuous tuning output of optical pulses;

and the first beam combiner (17) and the second beam combiner (21) are used for combining the optical paths and form a closed loop with the wavelength division multiplexer (8).

2. The acousto-optic-electro-mechanical linkage multi-wavelength tunable synchronous light source according to claim 1, wherein the first optical switch (3), the second optical switch (11), the third optical switch (14) and the fourth optical switch (18) are mechanical optical switches, acousto-optic switches or electro-optic switches, and different optical paths are switched by the optical switches to output pulses with different wavelengths.

3. The acousto-optic electro-mechanical linkage multi-wavelength tunable synchronous light source according to claim 1, wherein the first parametric medium (12) and the second parametric medium (13) are solid nonlinear media, and by utilizing nonlinear characteristics of the solid nonlinear media, nonlinear effects are generated with input seed pulses, spectrum is expanded, and the effect that an optical switch can switch an optical path is combined, so that the multi-wavelength synchronous light source is output.

4. The acousto-optic electro-mechanical linkage multi-wavelength tunable synchronous light source according to claim 1, wherein the first delay device (15), the second delay device (16), the third delay device (19) and the fourth delay device (20) adopt different structures to match corresponding lengths, and the lengths of the resonant cavities are changed by moving the positions so as to realize the functions of optical parametric amplification and narrowing filtering, thereby realizing continuous tuning output of optical pulses.

5. The acousto-optic electro-mechanical linkage multi-wavelength tunable synchronous light source according to claim 3, wherein the solid nonlinear medium is a lithium niobate crystal or a photonic crystal fiber.