CN114236884A - Lithium niobate-based high-speed high-threshold acousto-optic modulator - Google Patents
Lithium niobate-based high-speed high-threshold acousto-optic modulator Download PDFInfo
- Publication number
- CN114236884A CN114236884A CN202111587131.0A CN202111587131A CN114236884A CN 114236884 A CN114236884 A CN 114236884A CN 202111587131 A CN202111587131 A CN 202111587131A CN 114236884 A CN114236884 A CN 114236884A
- Authority
- CN
- China
- Prior art keywords
- acousto
- lithium niobate
- optic
- niobate crystal
- light
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/11—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on acousto-optical elements, e.g. using variable diffraction by sound or like mechanical waves
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
Abstract
The invention relates to a high-speed high-threshold acousto-optic modulator based on lithium niobate, belonging to the field of photoelectron; the acousto-optic modulator comprises an acousto-optic medium, a bonding layer, a transducer and a surface electrode; the sound passing surface of the acousto-optic medium is provided with the transducer through the bonding layer, the surface of the transducer is plated with the surface electrode, the acousto-optic medium is a lithium niobate crystal, the axis of the lithium niobate crystal [100] is vertical to the sound passing surface of the acousto-optic medium, the axis of the lithium niobate crystal [010] is positioned in the sound passing surface of the acousto-optic medium, and the included angle between the axis of the lithium niobate crystal [010] and incident light is 0.5 +/-0.3 degrees; meanwhile, the invention also plates an anti-reflection film on the light transmission surface of the acousto-optic medium, so that the utilization rate of the acousto-optic device on the light energy is improved, and the invention can better meet the modulation requirement of high speed and high threshold value.
Description
Technical Field
The invention relates to a high-speed high-threshold acousto-optic modulator based on lithium niobate, belonging to the field of photoelectrons.
Background
The acousto-optic modulator is an acousto-optic device for controlling laser intensity change, and is mainly formed from surface electrode, transducer, bonding layer, acousto-optic medium, matching network and high-frequency socket. The high-frequency socket is connected with the matching network through a lead, the surface electrode is arranged on the surface of the transducer, and the acousto-optic medium is connected with the transducer through a bonding layer. Radio frequency signals are transmitted to the electrode of the transducer through the high-frequency socket, the matching network and the gold wire (or the silicon-aluminum wire), the transducer converts the radio frequency signals into ultrasonic waves and transmits the ultrasonic waves to the acousto-optic medium, a refractive index grating is formed in the medium, and incident light and the refractive index grating generate acousto-optic interaction to generate diffracted light.
The tellurium oxide crystal has higher acousto-optic merit value and stable performance, is a common acousto-optic dielectric material for manufacturing an acousto-optic modulator, but the defect that the tellurium oxide crystal has lower acoustic wave speed and laser damage resistance threshold value cannot meet the requirement of rapid development.
Disclosure of Invention
In order to solve the technical problems, the invention provides a high-speed high-threshold acousto-optic modulator based on lithium niobate. The technical scheme is as follows:
the device comprises an acousto-optic medium, a bonding layer, a transducer and a surface electrode; the sound passing surface of the acousto-optic medium is provided with a transducer through a bonding layer, the surface of the transducer is plated with a surface electrode, the acousto-optic medium is a lithium niobate crystal, the [100] axis of the lithium niobate crystal is vertical to the sound passing surface of the acousto-optic medium, the [010] axis of the lithium niobate crystal is positioned in the sound passing surface of the acousto-optic medium, and the included angle between the [010] axis of the lithium niobate crystal and incident light is 0.5 +/-0.3 DEG
The lithium niobate crystal is used as an acousto-optic medium material instead of the traditional tellurium oxide crystal, although the acousto-optic merit value of the lithium niobate crystal is lower and is only one fifth of that of the tellurium oxide crystal, the lithium niobate crystal has high sound velocity and high laser damage resistance threshold, and can better meet the modulation requirement of high speed and high threshold.
Further, the lithium niobate crystal may include a normal lithium niobate crystal, a near stoichiometric lithium niobate crystal or a doped lithium niobate crystal.
Further, the doped lithium niobate crystal comprises doped magnesium oxide (MgO), and the concentration of the doped magnesium oxide is 2 mol% -5 mol%; or doped with zinc oxide (ZnO) with the concentration of 3mol percent to 6.5mol percent; or doped indium oxide (In)2O3) The concentration is 1mol percent to 1.5mol percent; or doped scandium oxide (Sc)2O3) The concentration is 1mol percent to 1.5mol percent; or doped with iron oxide (Fe)2O3) Which isThe concentration is 2mol percent to 4mol percent.
Furthermore, the invention also plates an antireflection film on the light passing surface of the acousto-optic medium according to the wavelength of light.
Optionally, when the light wavelength is visible light and near infrared band, the film material of the antireflection film is hafnium oxide (H)fO2) With silicon dioxide (SiO)2)。
Optionally, when the optical wavelength is in the short and medium wavelength bands, the film material of the antireflection film is hafnium oxide (H)fO2) And yttrium fluoride (YbF).
Further, before plating the antireflection film, plating aluminum oxide (A1) on the light passing surface of the acousto-optic medium2O3) And the transition layer is used for improving the adhesive force of the antireflection film and ensuring the laser damage resistance threshold of the lithium niobate crystal.
The invention has the beneficial effects that:
(1) the light pulse rise time is improved. When the ultrasonic longitudinal wave propagates along the direction of lithium niobate crystal [100], the sound wave speed is as high as 6570m/s, which is 1.6 times of the tellurium oxide longitudinal wave speed (4200m/s), and the sound wave speed is inversely proportional to the light pulse rise time of the acousto-optic device, so that under the same condition, the light pulse rise time of the lithium niobate acousto-optic device is only 1/1.6 of the light pulse rise time of the tellurium oxide acousto-optic device, that is, the light pulse rise time of the lithium niobate acousto-optic device is improved by nearly 40%.
(2) The capability of the acousto-optic device for bearing high-power laser is improved. Taking 1064nm continuous laser as an example, the tellurium oxide crystal can only bear less than 10W/mm2The common lithium niobate crystal can bear about 40W/mm2The acousto-optic device made of the doped lithium niobate crystal can bear 200W/mm2Obviously, the acousto-optic device based on the lithium niobate crystal greatly improves the capacity of bearing high-power laser.
(3) The acousto-optic merit value of the lithium niobate crystal is improved. The invention changes the light transmission direction and the lithium niobate crystal [010]]The angle between the axes is such that the incident o-ray is incident along the lithium niobate crystal [100]]The sound wave of the axial transmission has the best effect of acousto-optic interaction, and the acousto-optic merit value of the incident o light is 7.3 multiplied by 10-15S3The sound-light merit value of the lithium niobate crystal is improved by 5 percent compared with that of the conventional lithium niobate crystal. The acousto-optic merit value is in direct proportion to the diffraction efficiency of the acousto-optic device, so that the acousto-optic device based on the new cut lithium niobate crystal can obtain higher diffraction efficiency under the same condition. The higher the diffraction efficiency, the higher the utilization rate of the incident light energy, and the better the performance of the acousto-optic device.
(4) The adhesive force of the antireflection film is improved. According to the antireflection film theory, hafnium (H) oxide is used on the light passing surface of lithium niobatefO2) Silicon dioxide (SiO)2) Plating visible light and near infrared wave band (400 nm-2000 nm) reflection reducing film or using hafnium oxide (H)fO2) The yttrium fluoride (YbF) plating short and medium wave (2000 nm-5000 nm) antireflection film can raise the utilization rate of acousto-optic device to light energy, and further, said invention also includes a layer of aluminium oxide (A1) plated on the light-passing surface of lithium niobate crystal2O3) And the transition layer is plated with an antireflection film according to the light wavelength requirement, so that the adhesive force of the antireflection film is improved, and the stability of the antireflection film is ensured.
Drawings
FIG. 1 is a schematic structural diagram of a lithium niobate-based high-speed high-threshold acousto-optic modulator of the present invention;
in the figure, 1 is an acousto-optic medium, 2 is incident light, 3 is a sound-passing surface, 4 is a bonding layer, 5 is a transducer, 6 is a surface electrode, 7 is diffraction light, 8 is 0-order light, and 9 is a light-passing surface.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, a lithium niobate-based high-speed high-threshold acousto-optic modulator comprises an acousto-optic medium 1, a bonding layer 4, a transducer 5 and a surface electrode 6; the sound passing surface 3 of the acousto-optic medium 1 is provided with a transducer 5 through a bonding layer 4, the surface of the transducer 5 is plated with a surface electrode 6, and the acousto-optic medium 1 is a lithium niobate crystal.
In the embodiment of the invention, the material of the traditional acousto-optic medium is replaced by the tellurium oxide crystal, although the acousto-optic merit value of the lithium niobate crystal is lower and is only one fifth of that of the tellurium oxide crystal, the sound velocity of the lithium niobate crystal is fast, the laser damage resistance threshold is higher, and the modulation requirement of high speed and high threshold can be better met.
In the embodiment of the present invention, the lithium niobate crystal may be a doped lithium niobate crystal or an undoped lithium niobate crystal, where the undoped lithium niobate crystal may be divided into a normal lithium niobate crystal and a stoichiometric ratio lithium niobate crystal, where the normal lithium niobate crystal is a normal lithium niobate crystal, that is, a lithium niobate crystal on which doping treatment, stoichiometric ratio treatment, and other treatments have not been performed.
Compared with the conventional lithium niobate crystal with the same component, the performance of the lithium niobate crystal with the stoichiometric ratio in the aspects of electro-optic coefficient, nonlinear optical coefficient, periodic polarization reversal voltage, applied photorefractive and the like is greatly improved.
Compared with the conventional lithium niobate crystal and the stoichiometric ratio lithium niobate crystal, the doped lithium niobate crystal has a higher laser damage resistance threshold than the undoped lithium niobate crystal (the common lithium niobate crystal and the stoichiometric ratio lithium niobate crystal), and can meet the laser modulation requirement of higher power.
In the embodiment of the invention, the doped lithium niobate crystal in the acousto-optic medium 1 has a plurality of different doping modes, and can comprise doped magnesium oxide (MgO), wherein the concentration of the doped magnesium niobate crystal is 2 mol% -5 mol%; or doped with zinc oxide (ZnO) with the concentration of 3mol percent to 6.5mol percent; or doped indium oxide (In)2O3) The concentration is 1mol percent to 1.5mol percent; or doped scandium oxide (Sc)2O3) The concentration is 1mol percent to 1.5mol percent; or doped with iron oxide (Fe)2O3) The concentration is 2mol percent to 4mol percent. The doping mode can generally improve the laser damage resistance threshold of the doped lithium niobate crystal by more than 5 times compared with the common lithium niobate crystal.
In the preferred embodiment of the invention, a new crystal tangent is applied to the lithium niobate crystal to improve the acousto-optic merit value of the lithium niobate crystal. When the lithium niobate crystal is used for manufacturing an acousto-optic device, the commonly used crystal tangential direction is as follows: light transmission direction and lithium niobate crystal [010]]The angle between the axes is 35 deg., when the incident e-ray is incident with the edge 100]The effect of acousto-optic interaction of sound waves transmitted by the shaft is optimal, and the optimal value of incident e acousto-optic light is 6.95 multiplied by 10-15S3In terms of/kg. In the present invention, however, the light transmission direction is changed to the lithium niobate crystal [010]]The included angle between the axes designs a new tangential direction of the lithium niobate crystal: let lithium niobate crystal [100]]Sound surface 3, lithium niobate crystal with axis vertical to acousto-optic medium [010]]The axis is positioned in the sound passing surface 3 of the acousto-optic medium, and the incident light 2 and the lithium niobate crystal [010]]The included angle theta between the axes is 0.5 degrees +/-0.3 degrees, a radio frequency signal (RF) is transmitted to the transducer 5 through the surface electrode, the transducer 5 absorbs the radio frequency signal and converts the radio frequency signal into ultrasonic vibration, and the ultrasonic vibration is transmitted into the acousto-optic medium 1 through the bonding layer 4 to form an ultrasonic longitudinal wave in the acousto-optic medium 1, and the ultrasonic longitudinal wave is along the lithium niobate crystal [100]]The ultrasonic wave propagates in the axial direction, incident light 2 and ultrasonic longitudinal wave generate acousto-optic interaction to generate diffracted light 7, and the rest light except the diffracted light 7 in the incident light 2 is 0-order light 8. At this time, incident o light and lithium niobate crystal [100]]The sound wave generating acousto-optic interaction effect of axial transmission (sound velocity 6570m/s) is optimal, and the acousto-optic merit value of incident o light is 7.3 multiplied by 10-15S3Per kg; ultrasonic longitudinal wave edge crystal [100]]The axis propagates.
In the preferred embodiment of the invention, considering that the refractive index of the lithium niobate crystal is as high as 2.2, and the single-side residual reflection reaches 14% under the condition of no film coating, the light utilization rate is greatly influenced, so an antireflection film must be plated on the light transmission surface 9 of the lithium niobate crystal, and the utilization rate of the acousto-optic device on the light energy is improved. In order to improve the adhesion of an antireflection film and ensure the laser damage resistance threshold of the lithium niobate crystal, a layer of aluminum oxide (A1) is plated on the light passing surface 9 of the lithium niobate crystal firstly (the invention)2O3) And plating an antireflection film on the transition layer according to the light wavelength requirement. For visible light and near infrared wave band (400 nm-2000 nm), the antireflection film material on the light-passing surface 9 of the lithium niobate crystal is made of hafnium oxide (H)fO2) With silicon dioxide (SiO)2) Composition is carried out; for short and medium wave (2000 nm-5000 nm), the antireflection film material on the light passing surface 9 of the lithium niobate crystal is made of hafnium oxide (H)fO2) And yttrium fluoride (YbF).
In a specific embodiment of the invention, the invention utilizes 5 mol% MgO-doped lithium niobate crystal to manufacture a high-speed high-threshold acousto-optic modulator, the sound velocity is 6570m/s when ultrasonic longitudinal wave propagates along the crystal [100] axis, and the rising time of the light pulse reaches 96ns for the light beam with the diameter of 1 mm. Under the same condition, the sound speed of the acousto-optic modulator made of the tellurium oxide crystal is only 4200m/s, and the rise time of the light pulse needs 154 ns. It is clear that the new acousto-optic modulator improves the light pulse rise time by nearly 40%.
The high-speed high-threshold sound-light modulator can bear 200W/mm2The 1064nm laser can only bear less than 10W/mm of the conventional tellurium oxide acousto-optic modulator2The 1064nm laser obviously improves the capability of bearing high-power laser by the acousto-optic device based on the lithium niobate crystal.
The above examples of the present invention are merely illustrative of the present invention and are not intended to limit the embodiments of the present invention. Variations and modifications in other variations will occur to those skilled in the art upon reading the foregoing description. Not all embodiments are exhaustive. All obvious changes and modifications of the present invention are within the scope of the present invention.
In the description of the present invention, it is to be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "other end", "upper", "one side", "top", "inner", "outer", "front", "center", "both ends", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "disposed," "connected," "fixed," "rotated," and the like are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; the terms may be directly connected or indirectly connected through an intermediate, and may be communication between two elements or interaction relationship between two elements, unless otherwise specifically limited, and the specific meaning of the terms in the present invention will be understood by those skilled in the art according to specific situations.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (7)
1. A lithium niobate-based high-speed high-threshold acousto-optic modulator comprises an acousto-optic medium, a bonding layer, a transducer and a surface electrode; the sound passing surface of the acousto-optic medium is provided with a transducer through a bonding layer, and the surface of the transducer is plated with a surface electrode, and the acousto-optic medium is a lithium niobate crystal, the [100] axis of the lithium niobate crystal is vertical to the sound passing surface of the acousto-optic medium, the [010] axis of the lithium niobate crystal is positioned in the sound passing surface of the acousto-optic medium, and the included angle between the [010] axis of the lithium niobate crystal and incident light is 0.5 +/-0.3 degrees.
2. The lithium niobate-based high-speed high-threshold acousto-optic modulator according to claim 1, wherein the lithium niobate crystal comprises a near stoichiometric lithium niobate crystal or a doped lithium niobate crystal.
3. The lithium niobate-based high-speed high-threshold acousto-optic modulator of claim 2, wherein the doped lithium niobate crystal comprises doped magnesium oxide (MgO) with a concentration of 2 mol% to 5 mol%; or doped zinc oxide (ZnO) in a concentration of3 mol% -6.5 mol%; or doped indium oxide (In)2O3) The concentration is 1mol percent to 1.5mol percent; or doped scandium oxide (Sc)2O3) The concentration is 1mol percent to 1.5mol percent; or doped with iron oxide (Fe)2O3) The concentration is 2mol percent to 4mol percent.
4. The lithium niobate-based high-speed high-threshold acousto-optic modulator according to claim 1, wherein an antireflection film is plated on a light-passing surface of the acousto-optic medium according to the wavelength of light.
5. The lithium niobate-based high-speed high-threshold acousto-optic modulator according to claim 4, wherein when the wavelength of light is in the visible and near infrared bands, the material of the anti-reflection film is hafnium oxide (H)fO2) With silicon dioxide (SiO)2)。
6. The lithium niobate-based high-speed high-threshold acousto-optic modulator according to claim 4, wherein when the wavelength of light is in the short and medium wavelength band, the material of the anti-reflection film is hafnium oxide (H)fO2) And yttrium fluoride (YbF).
7. The lithium niobate-based high-speed high-threshold acousto-optic modulator according to claim 4, 5 or 6, further comprising plating alumina (A1) on the light-passing surface of the acousto-optic medium before plating the anti-reflection film2O3) And a transition layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111587131.0A CN114236884A (en) | 2021-12-23 | 2021-12-23 | Lithium niobate-based high-speed high-threshold acousto-optic modulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111587131.0A CN114236884A (en) | 2021-12-23 | 2021-12-23 | Lithium niobate-based high-speed high-threshold acousto-optic modulator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114236884A true CN114236884A (en) | 2022-03-25 |
Family
ID=80761932
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111587131.0A Pending CN114236884A (en) | 2021-12-23 | 2021-12-23 | Lithium niobate-based high-speed high-threshold acousto-optic modulator |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114236884A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114725767A (en) * | 2022-04-11 | 2022-07-08 | 哈尔滨工业大学 | Electro-optical Q-switch based on relaxor ferroelectric single crystal |
-
2021
- 2021-12-23 CN CN202111587131.0A patent/CN114236884A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114725767A (en) * | 2022-04-11 | 2022-07-08 | 哈尔滨工业大学 | Electro-optical Q-switch based on relaxor ferroelectric single crystal |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5853880B2 (en) | Light modulator | |
| CN111487793B (en) | Z-cut LNOI electro-optical modulator capable of improving modulation efficiency and application thereof | |
| CN114236884A (en) | Lithium niobate-based high-speed high-threshold acousto-optic modulator | |
| JP6033196B2 (en) | Manufacturing method of optical components | |
| JP3848093B2 (en) | Optical waveguide device, optical wavelength conversion device, and optical waveguide device manufacturing method | |
| JPS6014222A (en) | Optical wavelength converting element | |
| CN107305297A (en) | Broadband travelling-wave electrooptic modulator based on lithium niobate monocrystal film | |
| CN113419364B (en) | Groove auxiliary type acousto-optic modulator based on lithium niobate film | |
| CN217360480U (en) | Polarization-preserving double-crystal low-frequency acousto-optic frequency shifter | |
| JP4557264B2 (en) | Wavelength conversion element | |
| JP2000267056A (en) | Waveguide type optical device | |
| JPH0523413B2 (en) | ||
| CN212206096U (en) | Y-branch optical waveguide modulator chip | |
| JP6630852B2 (en) | Uses and devices of quaternary molybdenum / tungsten tellurate crystals | |
| CN215833739U (en) | Broadband frequency doubling waveguide device based on birefringence phase matching | |
| CN113031317A (en) | Miniaturized high extinction ratio modulation device and use method thereof | |
| JPH06308437A (en) | Optical control element | |
| JP2012078507A (en) | Optical waveguide element | |
| JP2004245991A (en) | Optical waveguide device and structure combining the same and optical transmission member | |
| JPS6150291B2 (en) | ||
| JPH0212135A (en) | Second harmonic wave generating element | |
| WO2023087211A1 (en) | Saw resonator and saw filter | |
| JP5099347B2 (en) | Light modulator | |
| JPH0523412B2 (en) | ||
| Liu et al. | Ultra-wide bandwidth thin film lithium niobate modulator with benzocyclobutene (BCB) bottom cladding and low-loss buried edge couplers |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |