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Investigations on the laser cutting of LiNbO3
摘要： In this work, we study the precision cutting technology of LiNbO3 which is belonged to brittle materials and difficult to machine. By using a femtosecond laser, we explore the influence of wavelengths on the cutting quality, the surface and cross-section morphology of the specimens were examined by optical microscopy and have been measured. Subsequently, two optimization processing solutions have been designed to cut LiNbO3 with high quality and high reproducibility, the thermal effect and chipping have been reduced obviously. At last, the complete cut through the plate of LiNbO3 has been achieved.
关键词： LiNbO3,Thermal influence,Femtosecond laser,Laser cutting
更新于2025-09-19 17:13:59
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3D polarization-dependent waveguide arrays in LiNbO3 crystal produced by femtosecond laser writing
摘要： Waveguide arrays are basic photonic elements in integrated optics. We propose a 3D hybrid-integrated waveguide array based on the femtosecond laser writing of lithium niobate (LiNbO3) crystals by engineering the layout of laser-induced tracks. The cross section of the structure is a cross-shaped geometry. The light propagation through this waveguide array shows polarization-dependent behaviors, which enables mode-coupling along either the vertical or the horizontal direction under excitation of linearly polarized light. This work opens new way to produce polarization-dependent optical devices in photonic systems by using femtosecond laser writing of LiNbO3.
关键词： Femtosecond laser writing,waveguide arrays,polarization-dependent devices,lithium niobate (LiNbO3)
更新于2025-09-19 17:13:59
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Good-Quality and High-Efficiency Dicing for Thick LiNbO3 Wafers Using Picosecond Laser Pulses
摘要： Lithium niobate (LiNbO3) has become popular with applications in electronics and communication industries due to its excellent electro-optical and nonlinear properties. This paper presents the influence of laser power, repetition frequency, number of subpulses, depth of each pass, and scanning velocity in picosecond laser dicing on multiple characteristics of LiNbO3 using the Taguchi method. By means of analysis of variance and analysis of relations between the characteristics, the optimal ps-laser-dicing parameter is obtained with good quality and high efficiency, which is applied to LiNbO3 products. The result indicates that picosecond laser dicing provides an alternative to machine thick LiNbO3 wafers with narrow kerf width, micro chipping, smooth surface, and high productivity.
关键词： thick lithium niobate,picosecond laser,LiNbO3 wafers,laser dicing,dicing quality optimization
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Cherenkov Generation of Wideband Terahertz Radiation using a Sub-Micron LiNbO <sub/>3</sub> Slab Waveguide
摘要： Terahertz (THz) radiation is critical to the areas of security, medicine, communications, and consumer applications. THz generation is often achieved using lithium niobate, LiNbO3, since it has a high nonlinear coefficient in this regime (d33=180 pm/V [1]). Dramatic improvement to the generation efficiency has been achieved by incorporating this material into waveguiding configurations [2,3], since waveguides allow the pump pulse to remain confined over large distance (millimeters or longer). To date, waveguides investigated for THz generation utilize transverse core dimensions larger than a few microns. However, when the waveguide core is sub-wavelength with respect to the pump wavelengths, as well as the generated THz wavelengths, another benefit is observed: substantial broadening of the generated THz bandwidth. Here, we report on a sub-wavelength SiO2-LiNbO3-SiO2 slab waveguide that produces wideband THz radiation and emits it in the form of Cherenkov waves. The investigated LiNbO3 slab waveguide has transverse core dimensions of 720 nm × 4 mm and a length of 100 μm. This waveguide is excited using an electric field pulse having a duration of 50 fs and a central-wavelength of 780 nm. Figure 1(a) shows the generated THz electric field pulse, which has the short duration of <1 ps. The power spectrum of the generated THz pulse is shown in Fig. 1(b), having a central-frequency of 6.9 THz and a full-width half-maximum (FWHM) bandwidth of 2.1 THz. Notably, LiNbO3 has a strong phonon resonance at 7.6 THz [4]. However, since the generated THz radiation is emitted as Cherenkov waves, it exits the sub-wavelength LiNbO3 core after propagating a distance much less than a wavelength. This characteristic minimizes the high loss of the LiNbO3 phonon resonance, allowing for generation to occur directly at this phonon resonance. As such, the sub-wavelength nature of the LiNbO3 core allows for dramatic improvement to the THz radiation bandwidth. The data is Fig. 1 is obtained by performing finite-difference time-domain simulations. Experimental verification of this result is currently underway. In this experimental work, the LiNbO3 slab waveguide instead has a length of 1 cm and the excitation pulses will have energies ranging up to 200 nJ.
关键词： wideband THz generation,Terahertz radiation,LiNbO3,Cherenkov waves,sub-wavelength waveguide
更新于2025-09-12 10:27:22
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[IEEE 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Fukuoka, Japan (2019.7.7-2019.7.11)] 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Antenna-Coupled Electrode Electro-Optic Modulator and 28 GHz-Band Wireless Signal Transfer over Fiber for 5G Mobile Systems
摘要： Signal conversion from 28 GHz-band wireless to optical signals and transfer over optical fiber were demonstrated successfully using a newly-designed antenna-coupled electrode LiNbO3 electro-optic modulator, which is suitable for uplinks in 5G mobile front-haul.
关键词： antenna,5G mobile systems,optical modulator,LiNbO3,radio-over-fiber,Microwave photonics
更新于2025-09-11 14:15:04
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Emerging Waveguide Technology || Lithium Niobate Optical Waveguides and Microwaveguides
摘要： Lithium niobate has attracted much attention since the 1970s due to its capacity to modify the light by means of an electric control. In this chapter, we review the evolution of electro-optical (EO) lithium niobate waveguides throughout the years, from Ti-indiffused wave-guides to photonic crystals. The race toward ever smaller EO components with ever-lower optical losses and power consumption has stimulated numerous studies, the challenge consisting of strongly confining the light while preserving low losses. We show how waveguides have evolved toward ridges or thin film-based microguides to increase the EO efficiency and reduce the driving voltage. In particular, a focus is made on an easy-to-implement technique using a circular precision saw to produce thin ridge waveguides or suspended membranes with low losses.
关键词： integrated optics,photonics,optical graded icing,electro-optics,LiNbO3
更新于2025-09-11 14:15:04
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A Tunable Low-Power Oscillator Based on High-Q Lithium Niobate MEMS Resonators and 65-nm CMOS
摘要： This paper presents a comprehensive guide to co-design piezoelectric RF-micro-electromechanical system (MEMS) resonators and CMOS for enabling voltage-controlled MEMS oscillators (VCMOs) that harness the best benefits out of both platforms. The analysis, focusing on understanding different tradeoffs among the tuning range, power consumption, gain, and phase noise, is generic to any kind of piezoelectric resonators and specific for Colpitts VCMOs. As a result of this paper, the first VCMO based on the heterogeneous integration of a high-Q lithium niobate (LiNbO3) micromechanical resonator and CMOS has been demonstrated. A LiNbO3 resonator array with a series resonance at 171.1 MHz, a Q of 410, and an electromechanically coupling factor of 12.7% is adopted, while the TSMC 65-nm RF LP CMOS technology is used to implement the feedback and tuning circuitry with an active area of 220 × 70 μm2. The frequency tuning of the VCMO is achieved by programming a binary weighted digital capacitor bank and a varactor that are both connected in series to the resonator. The best measured phase noise performance of the VCMO is ?72 and ?153 dBc/Hz at 1 kHz and 10-MHz offsets from 178.23- and 175.83-MHz carriers, respectively. The VCMO consumes a dc current of 60 μA from a 1.2-V supply while realizing a tuning range of 2.4 MHz (～1.4% fractional tuning range). Such VCMOs can be applied to enable ultralow power, low phase noise, and wideband RF signal synthesis for emerging applications in Internet of Things.
关键词： RF-micro-electromechanical system (MEMS),lithium niobate (LiNbO3),phase noise,oscillator,Internet of Things (IoT)
更新于2025-09-10 09:29:36
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High-Pressure Synthesis, Crystal Structure, Chemical Bonding, and Ferroelectricity of LiNbO <sub/>3</sub> -Type LiSbO <sub/>3</sub>
摘要： A polar LiNbO3 (LN)-type oxide LiSbO3 was synthesized by a high-temperature heat treatment under a pressure of 7.7 GPa and found to exhibit ferroelectricity. The crystal structural re?nement using the data of synchrotron powder X-ray di?raction and neutron di?raction and the electronic structure calculation of LN-type LiSbO3 suggest a covalent-bonding character between Sb and O. When comparing the distortion of BO6 in LN-type ABO3, the distortions of SbO6 in LiSbO3 and SnO6 in ZnSnO3, which included a B cation with a d10 electronic con?guration, were smaller than those of BO6 in LN-type oxides having the second-order Jahn?Teller active B cation, e.g., LiNbO3 and ZnTiO3. The temperature dependence of the lattice parameters, second harmonic generation, dielectric permittivity, and di?erential scanning calorimetry made it clear that a second-order ferroelectric?paraelectric phase transition occurs at a Curie temperature of Tc = 605 ± 10 K in LN-type LiSbO3. Further, ?rst-principles density functional theory calculation suggested that perovskite-type LiSbO3 is less stable than LN-type LiSbO3 under even high pressure, and the ambient phase of LiSbO3 directly transforms to LN-type LiSbO3 under high pressure. The phase stability of LN-type LiSbO3 and the polar and ferroelectric properties are rationalized by the covalent bonding of Sb?O and the relatively weak Coulomb repulsion between Li+ and Sb5+.
关键词： high-pressure synthesis,LiNbO3-type oxide,covalent bonding,ferroelectricity,second-order Jahn?Teller effect,LiSbO3
更新于2025-09-10 09:29:36
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Dynamical behavior of self-accelerating beams in LiNbO3 crystal with background illumination
摘要： We theoretically study the propagations and interactions of an Airy beam, soliton, and nonlinear self-accelerating beam in LiNbO3 crystal modulated by a shorter wavelength background beam. Simulations indicate that the self-accelerating beam and Airy beam can effectively propagate even in self-defocusing media, and the finite-energy Airy beam can generate bright solitons in a self-focusing medium. When two counter-shift Airy beams interact under appropriate conditions, fusion solitons, breathing solitons, and soliton pairs are generated. If we allow a photovoltaic soliton to collide with an Airy beam, X-type waves and soliton deflection occur at a specific phase shift and beam interval. Moreover, we find that the dynamics of two truncated nonlinear self-accelerating beams tend to exhibit straight propagation with attraction and repulsion in the in- and out-of-phase cases, respectively. These results are significant for applications related to optical routing and optical switches.
关键词： optical routing,LiNbO3 crystal,optical switches,Airy beam,nonlinear self-accelerating beam,soliton
更新于2025-09-09 09:28:46
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Flexible dual-mode SAW strain sensor based on crystalline LiNbO3 thin film
摘要： This work presents the development of flexible dual-mode surface acoustic wave (SAW) sensor based on single crystalline thin film lithium niobate (TF-LN). Numerical modeling is conducted to investigate the SAW propagation and the effects on strain sensitivity. The dependence of strain sensitivity on angles between the applied strain and SAW propagation direction is analyzed numerically and experimentally, showing that the maximum strain sensitivity is at 45° rather than longitudinal direction. 128° Y-cut TF-LN (~50 μm), obtained by micromachining technique, is utilized as the piezoelectric substrate to fabricate the SAW strain sensors with dual mode, namely Rayleigh mode and thickness shear mode (TSM). The sensor has excellent flexibility and demonstrates remarkable capability for an ultra-wide range strain measurement up to ±3000 με. Temperature effects on resonant frequency and strain sensitivity are investigated in the range of 25 ~ 100 ℃, and similar temperature characteristics are observed for the dual modes. A method of beat frequency between the dual modes is introduced which is able to eliminate the temperature effect on strain sensing, an on-chip temperature influence removing capability. All the results clearly show that this sensor exhibits great potential for applications in flexible electronics and microsystems.
关键词： dual-mode,temperature cancellation,flexible strain sensor,LiNbO3 thin film,surface acoustic wave
更新于2025-09-09 09:28:46