WO2022222234A1 - 一种基于液晶的可调谐激光器 - Google Patents

一种基于液晶的可调谐激光器 Download PDF

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WO2022222234A1
WO2022222234A1 PCT/CN2021/098062 CN2021098062W WO2022222234A1 WO 2022222234 A1 WO2022222234 A1 WO 2022222234A1 CN 2021098062 W CN2021098062 W CN 2021098062W WO 2022222234 A1 WO2022222234 A1 WO 2022222234A1
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liquid crystal
straight waveguide
resonant
light
tunable laser
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PCT/CN2021/098062
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English (en)
French (fr)
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吴佳辰
黄文彬
黄敏
刘晓同
徐忻怡
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苏州大学
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
    • H01S3/16—Solid materials
    • H01S3/1686—Liquid crystal active layer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/081—Construction or shape of optical resonators or components thereof comprising three or more reflectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/081—Construction or shape of optical resonators or components thereof comprising three or more reflectors
    • H01S3/0813—Configuration of resonator
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
    • H01S3/16—Solid materials

Definitions

  • the present invention relates to a laser, in particular to a liquid crystal-based tunable laser.
  • WGM optical microcavity of Whispering-Gallery Modes uses the principle of total optical reflection to achieve strong confinement of the light field, so that a mode with a high quality factor is generated in the resonator cavity, which constrains the light field well. on the micrometer scale. Therefore, WGM optical microcavity devices are considered to have very broad application prospects in the fields of nonlinear optics, optical communication, and optical sensing detection. Optical microcavity lasers have attracted more and more attention because of their small mode volume, low power consumption, high speed, and easy integration.
  • Tunable lasers are key components of modern optical fiber communication systems, optical sensing systems and spectral analysis systems.
  • the structure, material, process and other parameters of the resonator, gain medium and tunable filter device will affect the tuning effect and the working efficiency of the laser.
  • Tunable optical microcavity doped lasers need to be tuned by fiber gratings or fiber ring mirrors, which are greatly affected by the outside world.
  • the present invention proposes a liquid crystal-based tunable laser.
  • a liquid crystal-based tunable laser comprising: a pump light source and a photonic chip, the photonic chip comprising: a liquid crystal substrate layer, a liquid crystal guiding core layer disposed on the surface of the liquid crystal substrate layer, and a driving electrode;
  • the liquid crystal guide layer is a liquid crystal layer doped with a gain medium, and the liquid crystal guide layer is distributed with:
  • the optical transmission straight waveguide, the input end of the optical transmission straight waveguide is used to input the pump light source;
  • Optical output straight waveguide the output end of the optical output straight waveguide is used to output light of any wavelength
  • a resonant cavity including: one or more resonant microcavities cascaded with each other, the resonant cavity is respectively coupled to the optical transmission straight waveguide and the optical output straight waveguide;
  • the driving electrode is used to drive the liquid crystal molecular arrangement in the liquid crystal substrate layer, the light transmission straight waveguide part of the liquid crystal guiding core layer, the light output straight waveguide part and the resonant cavity part to change and change the refractive index of the corresponding part.
  • the invention discloses a liquid crystal-based tunable laser, which belongs to a chip-integrated laser, and has the advantages of simple structure, high integration degree, small volume, multi-stage cascade and high output efficiency.
  • the variation range of the liquid crystal refractive index of the liquid crystal substrate layer and the liquid crystal guiding core layer is between 1.55 and 1.7.
  • wavelength tunability can be effectively achieved.
  • the size of the included angle is 0 to ⁇ .
  • the total reflection propagation of light in the waveguide medium and the gain medium is realized, wherein the waveguide medium is a liquid crystal material, and the gain material can be a material with optical gain such as dye, perovskite material, and conjugated polymer.
  • the refractive index of the liquid crystal of the liquid crystal guiding core layer is greater than that of the liquid crystal of the liquid crystal substrate layer.
  • the radius of the resonant microcavity is more than 4um
  • the diameter of the optical transmission straight waveguide and/or the optical output straight waveguide is more than 2um
  • the overall structure of the tunable laser is above 20um.
  • the output wavelength covers light in the wavelength band of 380 nm to 780 nm, so that the output light in the visible light band can be tunable.
  • the liquid crystal guiding core layer is also distributed with:
  • the optical input straight waveguide, the input end of the optical transmission straight waveguide is used to input the pump light source;
  • the filter includes: one or more filter microcavities cascaded with each other, and the filter is respectively transmissively coupled with the optical input straight waveguide and the optical transmission straight waveguide.
  • the output efficiency is improved, and the incident light is filtered first.
  • the driving electrodes include:
  • the resonant cavity driving electrode is used to drive the change of the arrangement of liquid crystal molecules in the resonant cavity part of the liquid crystal guiding core layer;
  • the straight waveguide driving electrode is used to drive the liquid crystal molecular arrangement change in the light transmission straight waveguide part, the light output straight waveguide part and the light input straight waveguide part of the liquid crystal guiding core layer;
  • the substrate layer driving electrode is used to drive the liquid crystal molecular arrangement change in the liquid crystal substrate layer.
  • the driving electrode adopts a plurality of independent control modules to ensure the accuracy of control and the stability of the control system.
  • the driving electrodes are ITO glass with electrode patterns, and the electrode patterns correspond to the distribution of each part on the liquid crystal conducting core layer.
  • the structure of the resonant microcavity or the filter microcavity is one or more of the following:
  • Ring microcavity structure triangular microcavity structure, square microcavity structure, hexagonal microcavity structure, elliptical microcavity structure, stadium type microcavity structure.
  • multiple resonant microcavities or filter microcavities are cascaded in one or more of series integration, parallel integration, multi-segment integration, and array integration.
  • FIG. 1 is a schematic structural diagram of a tunable laser provided by an embodiment of the present invention.
  • FIG. 2 is a schematic diagram of a microring provided by an embodiment of the present invention.
  • FIG. 3 is a schematic diagram of a resonance mode provided by an embodiment of the present invention.
  • FIG. 4 is a second schematic structural diagram of a tunable laser provided by an embodiment of the present invention.
  • FIG. 5 is the arrangement of liquid crystal molecules and the patterned electrodes of the first resonant microring part provided by the embodiment of the present invention.
  • FIG. 6 is the arrangement of liquid crystal molecules and the patterned electrodes of the light transmission straight waveguide part provided by the embodiment of the present invention.
  • FIG. 7 is an experimental diagram of the wavelength of the output wave provided by the specific embodiment of the present invention.
  • FIG. 8 is an experimental diagram of the output wave wavelength provided by the second embodiment of the present invention.
  • 1- optical transmission straight waveguide 2- optical output straight waveguide, 3- resonant cavity, 31- first resonant micro-ring, 32- second resonating micro-ring, 4- filter, 41- first filtering micro-ring 42 -Second filter microring, 5-optical input straight waveguide, 6-drive electrode.
  • ordinal numbers “first”, “second”, etc. to describe common objects merely refers to different instances of similar objects, and is not intended to imply that objects so described must have temporal, spatial, ordinal aspects, or be in any order. other ways in the given order.
  • a liquid crystal-based tunable laser includes: a pump light source and a photonic chip, and the photonic chip includes: a liquid crystal a substrate layer, a liquid crystal guiding core layer disposed on the surface of the liquid crystal substrate layer, and a driving electrode 6;
  • the liquid crystal guide layer is a liquid crystal layer doped with a gain medium, and the liquid crystal guide layer is distributed with:
  • optical transmission straight waveguide 1 the input end of the optical transmission straight waveguide 1 is used to input the pump light source;
  • the optical output straight waveguide 2, the output end of the optical output straight waveguide 2 is used to output light of any wavelength
  • the resonant cavity 3 includes: one or more resonant microcavities cascaded with each other, and the resonant cavity 3 is respectively coupled to the optical transmission straight waveguide 1 and the optical output straight waveguide 2 through transmission;
  • the driving electrode 6 is used to drive the liquid crystal molecular arrangement in the liquid crystal substrate layer, the light transmission straight waveguide part of the liquid crystal guiding core layer, the light output straight waveguide part 2 and the resonator cavity 3 part to change the refractive index of the corresponding parts.
  • the laser can emit laser light spontaneously through resonance by adding a pump light source.
  • the above-mentioned gain material may be a material with optical gain, such as a dye, a perovskite material, and a conjugated polymer.
  • the pump light source is input from the input end of the optical transmission straight waveguide 1, the optical transmission straight waveguide 1 is transmissively coupled with the resonant cavity 3, and the resonant cavity 3 is also transmissively coupled with the optical output straight waveguide 2, and the output end of the optical output straight waveguide 2 outputs any arbitrary output. wavelength of light.
  • the wavelength of the pump source can be monochromatic light or mixed light.
  • the pump light source includes the near-infrared band to the near-ultraviolet band, and the input light can be a mixed light source, but only the light of a specific band can be coupled into the resonant microcavity of the resonant cavity 3.
  • the input light is coupled into the liquid crystal guide core layer composed of liquid crystal molecules by means of transmission coupling, and the transmission coupling coefficient can be controlled by controlling the distance between the straight waveguide and the resonant cavity 3 .
  • the arrangement change of the liquid crystal can realize the functions of the waveguide and the resonant cavity 3, which can be realized by the integration of the photo-alignment technology, and can be driven by a lower voltage.
  • liquid crystal is used as the light transmission and modulation medium, and functions such as waveguide and resonator 3 are realized by arranging the molecular orientation of liquid crystal microdomains. This makes the laser wavelength tunable.
  • the transmission coupling mode is adopted between the resonant cavity 3 and the optical transmission straight waveguide 1 and the optical output straight waveguide 2 , and the transmission coupling coefficient is controlled by controlling the distance between the straight waveguide and the resonant cavity 3 .
  • a detection element such as a spectrometer can be placed at the output end of the light output straight waveguide 2, and the detection range includes the near-infrared band to the near-ultraviolet band.
  • the invention discloses a liquid crystal-based tunable laser, which belongs to a chip integrated laser, has a simple structure, a high degree of integration, a small volume, can realize multi-stage cascade, high output efficiency, and a large free spectral range, and can meet various requirements.
  • the requirements for the use of the wavelength band are to achieve full coverage of the ultraviolet to the near-infrared band.
  • liquid crystal refractive index variation ranges of the liquid crystal substrate layer and the liquid crystal guiding core layer are both between 1.55 and 1.7.
  • the orientation of liquid crystal molecules in the entire chip is patterned by photo-alignment technology, and the birefringence property of liquid crystal and voltage driving are used to realize the change of the refractive index of the liquid crystal core layer and the liquid crystal substrate layer with the orientation of the liquid crystal molecules. And change, the refractive index changes in the range of 1.55 to 1.7, which can effectively achieve wavelength tunability.
  • the total reflection propagation of light in the waveguide medium and the gain medium is realized.
  • the diameter of the optical transmission straight waveguide 1 and/or the optical output straight waveguide 2 is more than 2um;
  • the overall structure of the tunable laser is above 20um.
  • the output wavelength covers light in the wavelength band of 380 nm to 780 nm, so that the output light in the visible light band can be tunable.
  • the radius of the resonant cavity 3 and the resonant wavelength series vary widely, so in order to To achieve tunable output light in the visible light band, the radius of the resonant microcavity needs to be more than 4um, the diameter of the straight waveguide needs to be more than 2um, and the overall structure of the tunable laser needs to be more than 20um to effectively output light in the wavelength range from 380nm to 780nm. .
  • the effective refractive index of the resonant cavity 3 is adjusted by voltage driving, and the resonant wavelength series will change at this time, realizing the modulation of the resonant wavelength and realizing the dynamic modulation of the laser broadband wavelength.
  • the optical alignment technology precision of liquid crystal molecules can reach 0.1um, so the structural precision of the laser can also reach 0.1um.
  • the spacing can reach more than 0.1um.
  • the guiding core layer is further distributed with:
  • optical input straight waveguide 5 the input end of the optical transmission straight waveguide 1 is used to input the pump light source;
  • the filter 4 includes: one or more filter microcavities cascaded with each other, and the filter 4 is respectively coupled to the optical input straight waveguide 5 and the optical transmission straight waveguide 1 through transmission.
  • the output efficiency is improved, and the incident light is filtered first.
  • the 4 tunable filters in the existing tunable laser need to introduce additional optical devices, which increases the complexity and insertion loss of the system.
  • the filter 4 of the present invention adopts the same manufacturing process and liquid crystal as the resonant cavity 3. material, which greatly reduces the difficulty of processing, and can be integrated by using photo-alignment technology, and can be driven at a lower voltage.
  • the driving electrodes include:
  • the resonant cavity driving electrode is used to drive the change of the arrangement of liquid crystal molecules in the resonant cavity part of the liquid crystal guiding core layer;
  • the straight waveguide driving electrode is used to drive the liquid crystal guiding core layer to change the arrangement of liquid crystal molecules in the light transmission straight waveguide 1 part, the light output straight waveguide 2 part, and the light input straight waveguide 5 part;
  • the substrate layer driving electrode is used to drive the liquid crystal molecular arrangement change in the liquid crystal substrate layer.
  • the driving electrode adopts a plurality of independent control modules to ensure the accuracy of control and the stability of the control system.
  • the driving electrodes are ITO glass with electrode patterns, and the electrode patterns correspond to the distribution of each part on the liquid crystal guiding core layer.
  • the driving electrodes are ITO glass.
  • the electrode patterning method can be performed by patterning and orienting the ITO glass, so that the electrode pattern corresponds to the liquid crystal arrangement pattern on the liquid crystal guiding core layer. Electrode patterning and liquid crystal patterning alignment can be achieved by area exposure.
  • the driving electrodes can adopt but are not limited to the following two driving methods:
  • One is the electric field driving of the electrodes, which uses the electro-optic effect of the liquid crystal to drive the liquid crystal molecules to rotate by applying a voltage.
  • the refractive index changes to change the resonance wavelength, and the alignment direction of the liquid crystal molecules in the light transmission straight waveguide 1 part of the liquid crystal core layer changes, so that there is a switch between the filter 4 and the laser part that does not include the filter 4;
  • photosensitive materials such as azo materials
  • the straight waveguide driving electrode of the optical transmission straight waveguide 1 can control whether the incident light can propagate in the straight waveguide, the aperture angle of the incident light, and the transmission coupling coefficient with the resonant microcavity, while the straight waveguide of the light output straight waveguide 2
  • the driving electrode can control the intensity of the output light wave and the transmission coupling coefficient with the resonant microcavity.
  • the driving electrode of the resonant cavity can control the effective refractive index of each resonant microcavity, so that the resonance conditions of the resonant cavity 3 are changed, thereby changing the resonant wavelength and Laser output range.
  • the remaining features and techniques are the same, except that the structure of the resonant microcavity or the filtering microcavity is one or more of the following:
  • microcavity structures such as annular microcavity structure, triangular microcavity structure, square microcavity structure, hexagonal microcavity structure, elliptical microcavity structure, stadium type microcavity structure, etc.
  • the remaining features and technologies are the same, the difference is that multiple resonant microcavities or filter microcavities are integrated through series integration, parallel integration, multi-segment integration, and array integration. cascade in one or more ways.
  • Different cascading methods may have the advantages of expanding the free spectral range, reducing crosstalk, flat passband, high stability, and small dispersion, but there may also be losses caused by center wavelength mismatch, high processing accuracy requirements, and temperature polarization. cause problems such as reduced stability.
  • Different cascading methods have their own advantages and disadvantages.
  • the pump source is modulated by the micro-ring structure of double straight waveguides, so that the laser outputs tunable light; the driving electrode pair is used to modulate the pump source.
  • the waveguide medium is modulated, thereby changing the effective refractive index of the resonant cavity 3 to output monochromatic light of any wavelength.
  • the liquid crystal guide core layer at the part of the double straight waveguide formed by the light transmission straight waveguide 1 and the light output straight waveguide 2 is formed by arranging liquid crystal molecules arranged at a certain angle to form a stepped waveguide structure. It is greater than the liquid crystal refractive index of the liquid crystal substrate layer, so as to realize the total reflection propagation of light in the waveguide medium and the gain medium.
  • the liquid crystal guiding core layer at part 3 of the resonant cavity is formed by arranging liquid crystal molecules whose alignment directions are at a certain angle to form a stepped waveguide resonant cavity.
  • the resonant cavity 3 includes: a first resonant micro-ring 31 resonating cavity and a second resonating micro-ring 32 resonating cavity.
  • the light of the pump source 2 is coupled from the optical transmission straight waveguide 1 into the resonant cavity of the first resonant microring 31, and oscillates and propagates in the resonant cavity.
  • the resonant cavity of the first resonant micro-ring 31 and the resonating cavity of the second resonating micro-ring 32 form resonance, so that the wave propagating in the resonating cavity of the first resonating micro-ring 31 is coupled into the resonating cavity of the first resonating micro-ring 31, and in the resonating cavity 3 Oscillation propagation.
  • the wave in the resonant cavity of the second resonant microring 32 is finally coupled into the optical output straight waveguide 2 for output.
  • the resonant microcavity adopts a series integration method, which has excellent performance indicators in various aspects but is difficult to prepare.
  • different cascading methods can be completed by the same liquid crystal photo-alignment technology.
  • the incident light can be filtered first, that is, the mixed light is input in the pump source 1 and filtered in the filter 4, so that the light before entering the resonator is similar to the monochromatic light, and the gain medium is increased by increasing the utilization.
  • the filter 4 includes: a first filter microring 41 resonant cavity and a second filter microring 42 resonant cavity.
  • Free spectral range refers to the spectral range between two resonant wavelengths.
  • FSR in is the length of cavity 3, and ⁇ m is the resonant wavelength of the cavity R is the radius of the resonant cavity, m is the number of resonances, and n eff is the effective refractive index of the resonant cavity 3 .
  • a resonant wave ⁇ 1 exists in the resonant cavity of the first resonant microring 31 , and after the resonant cavity of the first resonating microring 31 and the resonating cavity of the second resonating microring 32 form resonance, there is a resonance in the resonant cavity of the second resonating microring 32 wave ⁇ 2 , the condition for resonance is At this time, the resonant wave ⁇ 2 in the resonant cavity of the second resonant microring 32 is finally coupled into the optical output straight waveguide 2 for output.
  • the transmissive structural resonator is composed of two straight waveguides coupled with a micro-ring, and the coupled structural model is shown in Figure 2.
  • the transmissive resonator has two output ends, namely the through end and the drop end.
  • the input laser be E 1
  • E 2 the straight end of the resonator
  • E 4 the other part of the light energy coupled into the resonator
  • this part of the light is in In the cavity transmission around the ring, each time it passes through the coupling region, a part of the light energy is coupled to the straight waveguide, and is output through the downlink port of the resonant cavity, denoted as E 5 ; while the other part of the light continues to transmit around the ring, denoted as E 3 , and finally A closed loop of light is formed.
  • the resonant modes circulate in each resonator and can interact.
  • one cavity can be viewed as the spectral fidelity value of the resonant wavelength of the other cavity. Therefore, when the resonance conditions of two isolated cavities are satisfied, some resonance modes are enhanced while others are weakened, a phenomenon known as the Vernier effect.
  • the conditional formula for resonance is expressed as:
  • the electro-optical modulation driving of the double-ring structure liquid crystal is used to realize the functions of the microcavity laser.
  • the cascade mode used is shown in Figure 4.
  • the effective refractive index range of the liquid crystal guiding core layer and the liquid crystal substrate layer liquid crystal can reach 1.55 to 1.70, and the variation of the effective refractive index can reach about 0.2.
  • the three-layer waveguide structures of the first resonant microring 31 resonant cavity, the second resonating microring 32 resonant cavity and the double straight waveguide are all symmetrical structures, and the liquid crystals are arranged vertically to achieve The purpose of the maximum modulation amount, and there are patterned electrodes at the bottom of the integrated chip to achieve voltage modulation of liquid crystal molecules.
  • the natural light is incident on the pump source 1, and after being filtered by the filter 4, it enters the optical transmission straight waveguide 1.
  • the optical transmission straight waveguide 1 has a medium refractive index of 1.7 and an external medium with a refractive index of 1.55, forming a three-layer waveguide structure, which is incident from the incident end. and propagates through total reflection.
  • the refractive index of the medium of the optical transmission straight waveguide 1 is n 2
  • the refractive index of the outer medium is n 1 ;
  • the refractive index of the external medium of the first resonant microring 31 is n 3
  • the internal refractive index of the medium is n' 3
  • the effective refractive index is n 4 ;
  • the refractive index of the external medium of the second resonant micro-ring 32 is n 5
  • the internal refractive index of the medium is n' 5
  • the effective refractive index is n 6 ;
  • the refractive index of the medium of the light output straight waveguide 2 is n 8
  • the refractive index of the outer medium is n 7 .
  • the resonance formula of cavity 3 It can be obtained that the wavelength of the resonant wave coupled into the first resonant microring 31 is 502 nm, and the modulus is 200.
  • the resonant wave propagates in the micro-ring resonant cavity 3 , resonates with the second resonating micro-ring 32 , and is coupled into the second resonating micro-ring 32 .
  • Resonance relationship It can be obtained that the radius of the second resonant microring 32 is 5um, the effective refractive index of the initial refractive index is 1.600, and the distance between the second resonating microring 31 is 100 nm.
  • the wavelength of the resonant wave coupled into the second resonant microring 32 is 502 nm and the modulus is 100.
  • the distance between the second resonant micro-ring 32 and the optical output straight waveguide 2 is 100 nm, the resonant wave is coupled into the optical output straight waveguide 2 for total reflection and transmission, and a 502 nm monochromatic wave is output from the output end of the optical output straight waveguide 2 to realize a monochromatic wave.
  • the light output function is shown in Figure 7.
  • the liquid crystal can be electro-optically modulated by the patterned electrodes, the effective refractive index of the straight waveguide and the resonant cavity 3 can be changed, and then the wavelength of the resonant wave can be significantly changed to realize the dynamic modulation function.
  • the effective refractive index of the first resonant microring 31 is changed to 1.700
  • the wavelength of the resonant wave is changed to 628 nm
  • the modulus is changed to 170
  • the effective refractive index of the second resonant microring 32 is changed to 1.700
  • the wavelength of the resonant resonant wave becomes 628 nm
  • the modulus becomes 85
  • the wavelength of the monochromatic light at the output also becomes 628 nm, completing the tunable function of the laser, as shown in Figure 8.
  • the refractive indices of the first resonant microring and the second resonating microring can also be different according to the difference of the applied voltages, so as to realize modulation of other wavelengths.
  • the invention is a tunable laser based on liquid crystal.
  • the spectrum of the laser includes the near-infrared band to the near-ultraviolet band, but the output light is monochromatic light, the spectral half-width is 500GHz, and the output light wavelength range is 380nm to 780nm.
  • the invention can realize the laser tunable broadband wavelength dynamic modulation output function, the main working band can cover the near-ultraviolet to near-infrared band and the optical communication band under low voltage driving, and the volume is small and easy to integrate.

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Abstract

本发明公开一种基于液晶的可调谐激光器，包括：泵浦光源和光子芯片，光子芯片包括：液晶衬底层、设置于液晶衬底层表面的液晶导芯层以及驱动电极；液晶导芯层上分布有：光传输直波导，光传输直波导的输入端用于输入泵浦光源；光输出直波导，光输出直波导的输出端用于输出任意波长光；谐振腔，包括：一个或多个互相级联的谐振微腔，谐振腔分别与光传输直波导和光输出直波导透射耦合；驱动电极用于驱动液晶衬底层、液晶导芯层的光传输直波导部分、光输出直波导部分及谐振腔部分内液晶分子排布变化，改变其对应部分的折射率。本发明公开一种基于液晶的可调谐激光器结构简洁，集成化程度高，体积小，可以实现多级级联，输出高效率高。

Description

一种基于液晶的可调谐激光器 技术领域
本发明涉及一种激光器，具体涉及一种基于液晶的可调谐激光器。
背景技术
回音壁模式(Whispering-Gallery Modes，简称WGM)的光学微腔利用光学全反射的原理来实现对光场的强限制，使得谐振腔内产生品质因子较高的模式，将光场很好地约束在微米量级。因此，WGM光学微腔器件被认为在非线性光学、光通信、光传感检测等领域具有非常广泛的应用前景。光学微腔激光器因为具有小的模式体积、低功耗、高速率、易于集成等特点，越来越受到重视。
可调谐激光器是现代光纤通讯系统、光学传感系统和光谱分析系统的关键部件，结构主要包括泵浦源、谐振腔、增益介质和可调谐滤波器件。谐振腔、增益介质和可调谐滤波器件的结构、材料、工艺等参数均会影响调谐效果和激光器工作效率。
传统可调谐光学微腔激光器存在以下问题：
1)可调谐光学微腔拉曼激光器由于采用声光调制，精细度和自由光谱区难以同时满足小型化、高效率、易集成的要求。
2)可调谐光学微腔掺杂激光器需要利用光纤光栅或光纤环形镜调谐，受到外界影响较大。
发明内容
为了解决上述技术问题，本发明提出了一种基于液晶的可调谐激光器。
为了达到上述目的，本发明的技术方案如下：
一种基于液晶的可调谐激光器，包括：泵浦光源和光子芯片，光 子芯片包括：液晶衬底层、设置于液晶衬底层表面的液晶导芯层以及驱动电极；
液晶导芯层为掺杂有增益介质的液晶层，且液晶导芯层上分布有：
光传输直波导，光传输直波导的输入端用于输入泵浦光源；
光输出直波导，光输出直波导的输出端用于输出任意波长光；
谐振腔，包括：一个或多个互相级联的谐振微腔，谐振腔分别与光传输直波导和光输出直波导透射耦合；
驱动电极用于驱动液晶衬底层、液晶导芯层的光传输直波导部分、光输出直波导部分及谐振腔部分内液晶分子排布变化，改变其对应部分的折射率。
本发明公开一种基于液晶的可调谐激光器属于芯片化集成激光器，结构简洁，集成化程度高，体积小，可以实现多级级联，输出高效率高。
在上述技术方案的基础上，还可做如下改进：
作为优选的方案，液晶衬底层及液晶导芯层的液晶折射率变化范围均在1.55至1.7之间。
采用上述优选的方案，可以有效实现波长可调谐。
作为优选的方案，液晶导芯层内液晶分子与液晶衬底层内液晶分子之间存在夹角，夹角大小为0至π。
采用上述优选的方案，实现光在波导介质和增益介质中的全反射传播，其中波导介质为液晶材料，增益材质为可以为染料、钙钛矿材料、共轭聚合物等具有光学增益的材料。
作为优选的方案，液晶导芯层液晶折射率大于液晶衬底层液晶折射率。
采用上述优选的方案，实现光在波导介质和增益介质中的全反射传播。
作为优选的方案，谐振微腔的半径在4um以上；
光传输直波导和/或光输出直波导的直径在2um以上；
可调谐激光器的整体结构在20um以上。
采用上述优选的方案，输出波长涵盖380nm至780nm波段的光，实现可见光波段的输出光可调谐。
作为优选的方案，液晶导芯层上还分布有：
光输入直波导，光传输直波导的输入端用于输入泵浦光源；
滤波器，包括：一个或多个互相级联的滤波微腔，滤波器分别与光输入直波导和光传输直波导透射耦合。
采用上述优选的方案，提高输出效率，对入射光先进行滤波操作。
作为优选的方案，驱动电极包括：
谐振腔驱动电极，用于驱动液晶导芯层谐振腔部分内液晶分子排布变化；
直波导驱动电极，用于驱动液晶导芯层光传输直波导部分、光输出直波导部分、光输入直波导部分内液晶分子排布变化；
衬底层驱动电极，用于驱动所述液晶衬底层内液晶分子排布变化。
采用上述优选的方案，驱动电极采用多个独立的控制模组，保证控制的精确性和控制系统的稳定。
作为优选的方案，驱动电极为具有电极图案的ITO玻璃，且电极图案与液晶导芯层上各部分的分布相对应。
采用上述优选的方案，可以有效进行驱动。
作为优选的方案，谐振微腔或滤波微腔的结构为以下一种或多种：
环形微腔结构、三角形微腔结构、方形微腔结构、六角形微腔结构、椭圆微腔结构、体育场型微腔结构。
采用上述优选的方案，可以实现谐振或滤波。
作为优选的方案，多个谐振微腔或滤波微腔通过串联集成、并联集成、多段集成、阵列集成中的一种或多种方式进行级联。
采用上述优选的方案，根据具体情形选择合适的集成方式。
附图说明
为了更清楚地说明本发明实施例的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，应当理解，以下附图仅示出了本发明的某些实施例，因此不应被看作是对范围的限定，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他相关的附图。
图1为本发明实施例提供的可调谐激光器的结构示意图之一。
图2为本发明实施例提供的微环原理图。
图3为本发明实施例提供的共振模式原理图。
图4为本发明实施例提供的可调谐激光器的结构示意图之二。
图5为本发明实施例提供的第一谐振微环部分的液晶分子排布及图案化电极。
图6为本发明实施例提供的光传输直波导部分的液晶分子排布及图案化电极。
图7为本发明具体实施例一提供的输出波波长的实验图。
图8为本发明具体实施例二提供的输出波波长的实验图。
其中：1-光传输直波导，2-光输出直波导，3-谐振腔，31-第一谐振微环，32-第二谐振微环，4-滤波器，41-第一滤波微环42-第二滤波微环，5-光输入直波导，6-驱动电极。
具体实施方式
下面结合附图详细说明本发明的优选实施方式。
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普 通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
使用序数词“第一”、“第二”等等来描述普通对象仅仅表示涉及类似对象的不同实例，并且并不意图暗示这样被描述的对象必须具有时间上、空间上、排序方面或者以任意其它方式的给定顺序。
另外，“包括”元件的表述是“开放式”表述，该“开放式”表述仅仅是指存在对应的部件，不应当解释为排除附加的部件。
为了达到本发明的目的，一种基于液晶的可调谐激光器的其中一些实施例中，如图1所示，一种基于液晶的可调谐激光器包括：泵浦光源和光子芯片，光子芯片包括：液晶衬底层、设置于液晶衬底层表面的液晶导芯层以及驱动电极6；
液晶导芯层为掺杂有增益介质的液晶层，且液晶导芯层上分布有：
光传输直波导1，光传输直波导1的输入端用于输入泵浦光源；
光输出直波导2，光输出直波导2的输出端用于输出任意波长光；
谐振腔3，包括：一个或多个互相级联的谐振微腔，谐振腔3分别与光传输直波导1和光输出直波导2透射耦合；
驱动电极6用于驱动液晶衬底层、液晶导芯层的光传输直波导部分、光输出直波导2部分及谐振腔3部分内液晶分子排布变化，改变其对应部分的折射率。
激光器通过外加泵浦光源，能够通过谐振自发出射激光。
上述增益材质为可以为染料、钙钛矿材料、共轭聚合物等具有光学增益的材料。
泵浦光源从光传输直波导1的输入端输入，光传输直波导1与谐振腔3透射耦合，且谐振腔3还与光输出直波导2透射耦合，光输出直波导2的输出端输出任意波长光。
泵浦源波长可以为单色光或混合光。泵浦光源包含近红外波段至近紫外波段，输入光可以为混合光源，但只有特定波段的光才能耦合 进入谐振腔3的谐振微腔中。输入光采用透射耦合的方式耦合进入液晶分子构成的液晶导芯层，可以通过控制直波导和谐振腔3之间的距离控制透射耦合系数。
液晶的排布变化可以实现波导和谐振腔3的功能，利用光取向技术一体化实现，较低电压即可驱动。在光子芯片中使用液晶作为光传输和调制介质，通过排布液晶微区分子指向，实现波导和谐振腔3等功能，并利用液晶的电光调制效应，使得波导介质、增益介质折射率可调，进而使得激光器实现波长可调谐。
谐振腔3与光传输直波导1和光输出直波导2之间采用透射耦合方式，通过控制直波导和谐振腔3之间的距离控制透射耦合系数。光输出直波导2输出端可以放置如光谱仪的探测元件，探测范围包含近红外波段至近紫外波段。
本发明公开一种基于液晶的可调谐激光器属于芯片化集成激光器，结构简洁，集成化程度高，体积小，可以实现多级级联，输出高效率高，且自由光谱范围大，可以满足多种波段的使用要求，实现紫外到近红外波段的全覆盖。
为了进一步地优化本发明的实施效果，在另外一些实施方式中，其余特征技术相同，不同之处在于，液晶衬底层及液晶导芯层的液晶折射率变化范围均在1.55至1.7之间。
采用上述优选的方案，液晶分子在整个芯片的取向由光取向技术形成图案化排列，利用液晶的双折射性质和电压驱动实现液晶导芯层和液晶衬底层折射率随液晶分子的取向方式的变化而变化，折射率变化区间为1.55至1.7，可以有效实现波长可调谐。
为了进一步地优化本发明的实施效果，在另外一些实施方式中，其余特征技术相同，不同之处在于，液晶导芯层内液晶分子与液晶衬底层内液晶分子之间存在夹角，夹角大小为0至π。
采用上述优选的方案，实现光在波导介质和增益介质中的全反射 传播。
为了进一步地优化本发明的实施效果，在另外一些实施方式中，其余特征技术相同，不同之处在于，液晶导芯层液晶折射率大于液晶衬底层液晶折射率。
采用上述优选的方案，实现光在波导介质和增益介质中的全反射传播。
为了进一步地优化本发明的实施效果，在另外一些实施方式中，其余特征技术相同，不同之处在于，谐振微腔的半径在4um以上；
光传输直波导1和/或光输出直波导2的直径在2um以上；
可调谐激光器的整体结构在20um以上。
采用上述优选的方案，输出波长涵盖380nm至780nm波段的光，实现可见光波段的输出光可调谐。
由于谐振腔3的谐振频率由谐振腔3的有效折射率、半径、谐振波长级数决定，而有效折射率的变化范围有限、谐振腔3的半径和谐振波长级数变化范围较大，所以为了实现可见光波段的输出光可调谐，谐振微腔的半径需要达到4um以上，直波导的直径需要达到2um以上，可调谐激光器的整体结构需要达到20um以上，才能够有效输出波长380nm至780nm波段的光。
当谐振腔3的半径确定后，电压驱动调节谐振腔3的有效折射率，此时谐振波长级数会发生变化，实现谐振波长的调制，实现激光器宽波段波长动态调制。液晶分子的光取向技术精度可以到0.1um，所以激光器的结构精度也可以达到0.1um。谐振腔3和直波导之间的间距越小、不同谐振微腔之间的间距越小，则透射耦合系数越大，所以谐振腔3和直波导之间的间距、不同谐振微腔之间的间距可达0.1um以上。
为了进一步地优化本发明的实施效果，在另外一些实施方式中，其余特征技术相同，不同之处在于，导芯层上还分布有：
光输入直波导5，光传输直波导1的输入端用于输入泵浦光源；
滤波器4，包括：一个或多个互相级联的滤波微腔，滤波器4分别与光输入直波导5和光传输直波导1透射耦合。
采用上述优选的方案，提高输出效率，对入射光先进行滤波操作。
现有的可调谐激光器中的可调谐滤波器4件需引入额外光学器件，增大了系统的复杂度和插入损耗，本发明的滤波器4采用的是和谐振腔3相同的制作工艺和液晶材料，大大减小了加工难度，可以利用光取向技术一体化实现，较低电压即可驱动。
进一步，驱动电极包括：
谐振腔驱动电极，用于驱动液晶导芯层谐振腔部分内液晶分子排布变化；
直波导驱动电极，用于驱动液晶导芯层光传输直波导1部分、光输出直波导2部分、光输入直波导5部分内液晶分子排布变化；
衬底层驱动电极，用于驱动液晶衬底层内液晶分子排布变化。
采用上述优选的方案，驱动电极采用多个独立的控制模组，保证控制的精确性和控制系统的稳定。
进一步，驱动电极为具有电极图案的ITO玻璃，且电极图案与液晶导芯层上各部分的分布相对应。
采用上述优选的方案，可以有效进行驱动。
驱动电极为ITO玻璃。电极图案化方式可以通过对ITO玻璃进行图案化取向，使得电极图案和液晶导芯层上液晶排布图案相对应。电极图案化和液晶图案化对位可以通过区域曝光方式实现。驱动电极可以但不限于采用以下两种驱动方式：
一种是电极的电场驱动，利用液晶的电光效应来通过施加电压来驱动液晶分子转动，液晶导芯层谐振腔3部分和液晶衬底层内的液晶分子排列方向发生变化，使得谐振腔3的有效折射率发生变化进而改变谐振波长，液晶导芯层光传输直波导1部分内的液晶分子排列方向 发生变化可以使得滤波器4和不包括滤波器4的激光器部分之间存在开关；
一种是掺入光敏材料(例如偶氮材料)，在光场调制下，光敏材料会带来液晶导芯层和液晶衬底层内液晶分子的转动，在光场驱动时还需要控制驱动光的聚焦、波长与光敏材料对应。
进一步，光传输直波导1的直波导驱动电极可以控制入射光能否在直波导中传播、入射光的孔径角以及和谐振微腔之间的透射耦合系数，而光输出直波导2的直波导驱动电极可以控制输出光波的强度以及和谐振微腔之间的透射耦合系数，谐振腔驱动电极可以控制各谐振微腔的有效折射率，使得谐振腔3的谐振条件发生改变，进而改变谐振波长以及激光输出范围。
为了进一步地优化本发明的实施效果，在另外一些实施方式中，其余特征技术相同，不同之处在于，谐振微腔或滤波微腔的结构为以下一种或多种：
环形微腔结构、三角形微腔结构、方形微腔结构、六角形微腔结构、椭圆微腔结构、体育场型微腔结构等复杂微腔结构。
采用上述优选的方案，可以实现谐振或滤波。
为了进一步地优化本发明的实施效果，在另外一些实施方式中，其余特征技术相同，不同之处在于，多个谐振微腔或滤波微腔通过串联集成、并联集成、多段集成、阵列集成中的一种或多种方式进行级联。
采用上述优选的方案，根据具体情形选择合适的集成方式。
不同的级联方式可能会有扩大自由光谱范围、减少串扰、通带平坦、稳定性高、色散小等优点，但也可能会有中心波长失配造成的损耗、加工精度要求高、温度极化造成稳定性降低等问题。不同的级联方式都包含各自的优缺点。
以上多种实施方式可交叉并行实现。
为了更好地对本发明所公开的基于液晶的可调谐激光器进行理解，下面介绍一实施例，使用双直波导的微环结构对泵浦源进行调制，使得激光器输出可调谐光；使用驱动电极对波导介质进行调制，进而改变谐振腔3的有效折射率，实现输出任意波长的单色光。
光传输直波导1和光输出直波导2所形成的双直波导部分处的液晶导芯层采用排列方向成一定夹角的液晶分子排列而成，形成阶梯式波导结构，液晶导芯层液晶折射率大于液晶衬底层液晶折射率，从而实现光在波导介质和增益介质中的全反射传播。
谐振腔3部分处的液晶导芯层采用排列方向成一定夹角的液晶分子排列而成，形成阶梯式波导谐振腔。谐振腔3包括：第一谐振微环31谐振腔和第二谐振微环32谐振腔。
泵浦源2的光从光传输直波导1耦合进入第一谐振微环31谐振腔，并在谐振腔中振荡传播。第一谐振微环31谐振腔和第二谐振微环32谐振腔形成共振，使得第一谐振微环31谐振腔中传播的波耦合进入第一谐振微环31谐振腔，并在谐振腔3中振荡传播。第二谐振微环32谐振腔中的波最后耦合进入光输出直波导2中进行输出，通过结构设计和参数匹配，实现设定波长的单色光输出。该实施例中，谐振微腔采用了串联集成的方式，各方面性能指标优异但制备难度较大，而在不同应用场景中可以通过同样的液晶光取向技术完成不同的级联方式。
为了提高输出效率，可以先对入射光进行滤波操作，即在泵浦源1输入混合光，在滤波器4中进行滤波，使得进入谐振腔之前的光近似于单色光，调高增益介质的利用率。滤波器4包括：第一滤波微环41谐振腔和第二滤波微环42谐振腔。
自由光谱范围(FSR)，是指两个谐振波长之间的光谱范围。
FSR的定义是：
Figure PCTCN2021098062-appb-000001
其中
Figure PCTCN2021098062-appb-000002
为谐振腔3长，λ m 为谐振腔的谐振波长
Figure PCTCN2021098062-appb-000003
R为谐振腔半径，m为谐振次数，n eff为谐振腔3的有效折射率。
上述两个半径不同的谐振微环谐振腔的总FSR可以表示为：m 1FSR 1＝m 2FSR 2＝FSR total。在第一谐振微环31谐振腔中存在谐振波λ 1，在第一谐振微环31谐振腔和第二谐振微环32谐振腔形成共振后，在第二谐振微环32谐振腔中存在谐振波λ 2，共振的条件为
Figure PCTCN2021098062-appb-000004
此时第二谐振微环32谐振腔中的谐振波λ 2最后耦合进入光输出直波导2中进行输出。
当R 1、R 2确定时，n 1、n 2发生变化，要想输出调制后的λ' 1、λ' 2，则需要找到匹配的m' 1、m' 2，即为选频过程。
为了更好地理解上述内容，以下进行原理描述。
透射式结构谐振腔由两根直波导和微环耦合构成，耦合结构模型如图2所示。透射式谐振腔有两个输出端，即直通端和下路端。设输入的激光为E 1，在耦合区域有一部分光能量通过直波导直接输出，即谐振腔的直通端，记为E 2；另一部分光能量耦合进入谐振腔记为E 4，这部分光在腔内绕环传输，每次经过耦合区域时，一部分光能量耦合到直波导，通过谐振腔的下行端口输出，记为E 5；而另一部分光则继续绕环传输，记为E 3，最终形成光的闭合回路。
在稳定状态下，通过两个耦合区域的光将达到一个动态均衡状态。用谐振腔的谐振公式表达即为：
Figure PCTCN2021098062-appb-000005
如图3所示，在耦合的回音廊模腔中，共振模式在各谐振器中循环，可以相互作用。在强相互作用的情况下，一个腔可以看作是另一个腔的共振波长的谱保真值。因此，当满足两个孤立腔的共振条件时，某些共振模式会增强，而其他模式会减弱，这种现象称为游标效应。 用共振的条件公式表达即为：
Figure PCTCN2021098062-appb-000006
在其上实施例的基础上，举两个具体实施例。
实施例一：
采用双环结构液晶的电光调制驱动，实现微腔激光器的各项功能，采用的级联方式如图4所示。液晶导芯层和液晶衬底层液晶的有效折射率范围可以达到1.55至1.70，有效折射率的变化可达0.2左右。
如图5和6所示，第一谐振微环31谐振腔、第二谐振微环32谐振腔和双直波导的三层波导结构采用的均为对称结构，液晶排列方式均为垂直排列以实现最大调制量的目的，且集成芯片底部有图案化电极以实现电压调制液晶分子。
采用自然光入射泵浦源1，经过滤波器4滤波后进入光传输直波导1中，光传输直波导1介质折射率为1.7，外部介质折射率为1.55，构成三层波导结构，从入射端入射并全反射传播。
光传输直波导1部分介质折射率为n 2，其外部介质折射率为n 1；
第一谐振微环31外部介质折射率为n 3，其内部质折射率为n' 3，有效折射率为n 4；
第二谐振微环32外部介质折射率为n 5，其内部质折射率为n' 5，有效折射率为n 6；
光输出直波导2部分介质折射率为n 8，其外部介质折射率为n 7。
第一谐振微环31半径为10um，初始有效折射率为n 4＝1.600，和光传输直波导1之间的间距为100nm。由谐振腔3的谐振公式
Figure PCTCN2021098062-appb-000007
Figure PCTCN2021098062-appb-000008
可得，耦合进入第一谐振微环31的谐振波波长为502nm，模数为200。
谐振波在微环谐振腔3中传播，和第二谐振微环32发生共振，耦合进入第二谐振微环32。由共振的关系式
Figure PCTCN2021098062-appb-000009
可得，第二谐 振微环32半径为5um，初始折射率有效折射率为1.600，和第一谐振微环31之间的间距为100nm。
同样由谐振腔3的谐振公式
Figure PCTCN2021098062-appb-000010
可得，耦合进入第二谐振微环32的谐振波波长为502nm，模数为100。
第二谐振微环32和光输出直波导2的间距为100nm，谐振波耦合进入光输出直波导2并进行全反射传输，从光输出直波导2输出端输出502nm的单色波，实现了单色光输出功能，如图7所示。
由于液晶可由图案化电极进行电光调制，改变直波导和谐振腔3的有效折射率，进而可以显著改变谐振波的波长，实现动态调制功能。
在实施例二中，将第一谐振微环31的有效折射率改变为1.700，谐振波的波长变为628nm，模数变为170，而第二谐振微环32的有效折射率变为1.700，共振的谐振波波长变为628nm，模数变为85，输出端的单色光波长也变为628nm，完成了激光器的可调谐功能，如图8所示。第一谐振微环和第二谐振微环的折射率也可根据两者施加电压的不同而采用不同的折射率，进而实现其他波长的调制。
本发明一种基于液晶的可调谐激光器，激光器的光谱包含近红外波段至近紫外波段，但输出光为单色光，光谱半宽为500GHz，输出光波长范围为380nm至780nm。本发明可以实现激光可调谐的宽波段波长动态调制输出功能，低电压驱动下主要工作波段可以覆盖近紫外至近红外波段、光通信波段，且体积小、易于集成。
上述实施例只为说明本发明的技术构思及特点，其目的在于让本领域普通技术人员能够了解本发明的内容并加以实施，并不能以此限制本发明的保护范围，凡根据本发明精神实质所作的等效变化或修饰，都应涵盖在本发明的保护范围内。

Claims (10)

  1. 一种基于液晶的可调谐激光器，其特征在于，包括：泵浦光源和光子芯片，所述光子芯片包括：液晶衬底层、设置于所述液晶衬底层表面的液晶导芯层以及驱动电极；
    所述液晶导芯层为掺杂有增益介质的液晶层，且所述液晶导芯层上分布有：
    光传输直波导，所述光传输直波导的输入端用于输入泵浦光源；
    光输出直波导，所述光输出直波导的输出端用于输出任意波长光；
    谐振腔，包括：一个或多个互相级联的谐振微腔，所述谐振腔分别与所述光传输直波导和光输出直波导透射耦合；
    所述驱动电极用于驱动所述液晶衬底层、液晶导芯层的光传输直波导部分、光输出直波导部分及谐振腔部分内液晶分子排布变化，改变其对应部分的折射率。
  2. 根据权利要求1所述的基于液晶的可调谐激光器，其特征在于，
    所述液晶衬底层及液晶导芯层的液晶折射率变化范围均在1.55至1.7之间。
  3. 根据权利要求1所述的基于液晶的可调谐激光器，其特征在于，
    所述液晶导芯层内液晶分子与所述液晶衬底层内液晶分子之间存在夹角，夹角大小为0至π。
  4. 根据权利要求1所述的基于液晶的可调谐激光器，其特征在于，
    所述液晶导芯层液晶折射率大于所述液晶衬底层液晶折射率。
  5. 根据权利要求1所述的基于液晶的可调谐激光器，其特征在于，
    所述谐振微腔的半径在4um以上；
    所述光传输直波导和/或光输出直波导的直径在2um以上；
    所述可调谐激光器的整体结构在20um以上。
  6. 根据权利要求1-5任一项所述的基于液晶的可调谐激光器，其特征在于，所述液晶导芯层上还分布有：
    光输入直波导，所述光传输直波导的输入端用于输入泵浦光源；
    滤波器，包括：一个或多个互相级联的滤波微腔，所述滤波器分别与所述光输入直波导和光传输直波导透射耦合。
  7. 根据权利要求6所述的基于液晶的可调谐激光器，其特征在于，所述驱动电极包括：
    谐振腔驱动电极，用于驱动所述液晶导芯层谐振腔部分内液晶分子排布变化；
    直波导驱动电极，用于驱动所述液晶导芯层光传输直波导部分、光输出直波导部分、光输入直波导部分内液晶分子排布变化；
    衬底层驱动电极，用于驱动所述液晶衬底层内液晶分子排布变化。
  8. 根据权利要求7所述的基于液晶的可调谐激光器，其特征在于，所述驱动电极为具有电极图案的ITO玻璃，且所述电极图案与所述液晶导芯层上各部分的分布相对应。
  9. 根据权利要求6所述的基于液晶的可调谐激光器，其特征在于，
    所述谐振微腔或滤波微腔的结构为以下一种或多种：
    环形微腔结构、三角形微腔结构、方形微腔结构、六角形微腔结构、椭圆微腔结构、体育场型微腔结构。
  10. 根据权利要求6所述的基于液晶的可调谐激光器，其特征在于，多个所述谐振微腔或滤波微腔通过串联集成、并联集成、多段集成、阵列集成中的一种或多种方式进行级联。
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