Enhanced Electro-Optic Property in ${\rm LiNbO}_{3}$ by Electric Field Domain Inversion
TL;DR: In this paper, a Mach-Zehnder interferometric setup is used and the voltage required for phase reversal of the fringe pattern is noted for single domain and domain inverted sample.
Abstract: Change in the value of half-wave voltage of ${\rm LiNbO}_{3}$ ( $z$ -cut) before and after high electric field domain inversion at room temperature has been reported. For verification, a Mach–Zehnder interferometric setup is used and the voltage required for phase reversal of the fringe pattern is noted for single domain and domain inverted sample. The technique of the used domain inversion process is discussed and confirmation of the domain inversion is also done. As the half-wave voltage decreases after domain inversion, it may be assumed that the overall electro-optic property of ${\rm LiNbO}_{3}$ has been enhanced. This might possibly been caused by the internal field compensating the spontaneous polarization of the crystal.
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TL;DR: In this article, the domain inversion is used in a simple fashion to improve the performance of a Z-cut highly integrated LiNbO3 optical modulator (LNOM).
Abstract: Abstract In this paper, the domain inversion is used in a simple fashion to improve the performance of a Z-cut highly integrated LiNbO3 optical modulator (LNOM). The Z-cut modulator having ≤3V$ \\le 3 \\;{\\rm{V}}$ switching voltage and bandwidth of 15GHz$15 \\;{\\rm{GHz}}$ for an external modulator in which traveling-wave electrode length Lm${L_{\\rm{m}}}$ imposed the modulating voltage, the product of Vπ${V_\\pi}$ and Lm${L_{\\rm{m}}}$ is fixed for a given electro-optic material (EOM). An investigation to achieve a low Vπ${V_\\pi}$ by both magnitude of the electro-optic coefficient (EOC) for a wide variety of EOMs has been reported. The Sellmeier equation (SE) for the extraordinary index of congruent LiNbO3 is derived. The predictions related to phase matching are accurate between room temperature and 250 °C and wavelength ranging from 0.4 to 5 μm. The SE predicts more accurate refractive indices (RI) at long wavelengths. The different overlaps between the waveguides for the Z-cut structure are shown to yield a chirp parameter that can able to adjust 0–0.7. Theoretical results are perfectly verified by simulated results.
3 citations
Cites background from "Enhanced Electro-Optic Property in ..."
...Since electric field poled lithium niobate (LN) was first demonstrated [12], it is very much interesting to use periodically poled LiNbO3 (PPLN) for optical applications [13]....
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TL;DR: In this article, the temperature stability of the LiNbO3 modulator under dynamic electric field is studied and dynamic thermal insensitive (TI) propagating orientation is sought, and an effective method is developed to find the thermally insensitive orientations.
Abstract: The electro-optical crystals exhibit thermally insensitive optic propagation orientations, which satisfy the demand of outdoor industry and military applications. With the aid of wave coupling theory, the temperature stability of the LiNbO3 modulator under dynamic electric field is studied and dynamic thermal insensitive (TI) propagating orientation is sought. It is found that a number of propagation orientations have a dramatically different temperature property when the electric field is varied significantly. The temperature drift of light intensity in specific static TI orientation is raise by 3 orders of magnitude. While for dynamic TI orientation, the effect of the electric field is very limited and the temperature drift of modulated intensity can be controlled below 0.3%. The change of electric field orientation does not influence the temperature characteristics of dynamic TI orientation. An effective method is developed to find the thermally insensitive orientations. And the method is suitable for any type of electro-optic crystal with an applied electric field along arbitrary directions.
3 citations
TL;DR: A simple interferometric technique for measurement of the internal field (IF) in a ferroelectric crystal has been proposed in this article, where the electro-optic property of lithium niobate is exploited for quantitative analysis of its internal field.
Abstract: A simple interferometric technique for measurement of the internal field (IF) in a ferroelectric crystal has been proposed. This technique has several advantages over the other methods used previously for evaluation of IFs in ferroelectric crystals. Here, the electro-optic property of lithium niobate is exploited for quantitative analysis of its IF. The strength of IF obtained using this technique lies within the range given in the literature. However, at frustrated domain inversion state, the measured value of IF shows a reduced value. A possible reason for this reduction based on the defect model has been discussed.
2 citations
TL;DR: In this paper, it was shown experimentally that this internal field is a function of the molecular configuration in a particular domain and also on the stability of that particular configuration. And the internal field was measured using interferometric technique, while the variation of domain configuration is brought about by room temperature high voltage electric field poling.
Abstract: Congruent lithium niobate is characterized by its internal field, which arises due to defect clusters within the crystal Here, it is shown experimentally that this internal field is a function of the molecular configuration in a particular domain and also on the stability of that particular configuration The measurements of internal field are done using interferometric technique, while the variation of domain configuration is brought about by room temperature high voltage electric field poling
1 citations
References
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TL;DR: In this article, the authors review progress in quasi-phase-matched optical parametric oscillators in bulk periodically poled LiNbO3, and demonstrate an oscillation threshold as low as 0.012 mJ with a Q-switched pump laser and pumping at greater than ten times threshold without damage.
Abstract: We review progress in quasi-phase-matched optical parametric oscillators in bulk periodically poled LiNbO3. Using the electric-field poling process, we can reliably fabricate 0.5-mm-thick crystals with uniform domain structures over a 15-mm length. Periodically poled material retains the low-loss and bulk power handling properties of single-domain LiNbO3, and quasi phase matching permits noncritical phase matching with d33, the highest-valued nonlinear coefficient. Optical parametric oscillators pumped by 1.064-μm pulsed Nd:YAG lasers have been operated over the wavelength range 1.4–4 μm with tuning by temperature or by quasi-phase-matched period. We have shown an oscillation threshold as low as 0.012 mJ with a Q-switched pump laser and pumping at greater than ten times threshold without damage. We have also demonstrated a cw doubly resonant oscillator near 1.96 μm pumped directly with a commercial cw diode laser at 978 nm.
1,167 citations
"Enhanced Electro-Optic Property in ..." refers methods in this paper
...Large numbers of optoelectronic devices like second harmonic generator, parametric oscillators, THz wave generator, modulators and beam scanners have been built using the control of ferroelectric domain process [3]–[6]....
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TL;DR: In this paper, the most important properties of lithium niobate crystals for photonic applications are reviewed, acting on stoichiometry, sample structure, doping and domain structure of the crystals, these properties are governed, and can be taylored for each specific application.
Abstract: In this paper the most important properties of lithium niobate crystals for photonic applications are reviewed. We will summarize how acting on the stoichiometry, sample structure, doping and domain structure of the crystals, these properties are governed, and can be taylored for each specific application. Finally we present a review of photonic applications in a wide spectrum of fields as lasers and non-linear optics, optical communications, optical memories, and diffractive optics.
557 citations
"Enhanced Electro-Optic Property in ..." refers methods in this paper
...Large numbers of optoelectronic devices like second harmonic generator, parametric oscillators, THz wave generator, modulators and beam scanners have been built using the control of ferroelectric domain process [3]–[6]....
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Book•
01 Jan 1989493 citations
"Enhanced Electro-Optic Property in ..." refers background in this paper
...L ITHIUM Niobate (LiNbO3) is a negative uniaxial crystal having tremendous application in integrated optics because of its ability of guided wave control via its electrooptic, acousto-optic, birefringence, non-linearity etc properties [1], [2]....
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Book•
01 Jan 1990
TL;DR: In this paper, a phase diagram for the LiO2-0-Nb^O 2O^O 5 system is presented for the single-crystal lithium niobate.
Abstract: Introduction Physico-chemical properties of lithium metaniobate: Phase diagram for the Li^O2-0-Nb^O 2O^O5 system Crystal structure of lithium metaniobate Crystal-chemical features of metaniobates of alkali metals Phase formation in LN Crystals Methods of obtaining single crystals of lithium niobate Peculiarities of growth of LN single crystals Synthesis of the charge and preparation of the melt Choice of the optimum conditions for growth Growth conditions for LN crystals of a constant radius High-temperature annealing and formation of single-domains in crystal The Stepanov technique Electric phenomena arising in crystallization of LN Defect structure of single-crystal lithium niobate: Morphology and macro-defects Point defects in LN Formation of F centres in LN crystals Twinning in LN crystals The domain structure of lithium metaniobate crystals: Ferroelectric domains in lithium metaniobate Selective etching of LN crystals Growth domain structure Formation of a stationary domain structure Depolarisation mechanisms of lithium metaniobate crystals The influence of temperature gradients on domain formation in the process of crystal growth and annealing The effect of annealing on the near-surface domain structure The regular domain structure in LN crystals Electrical properties of lithium metaniobate: Electric conductivity Dielectric properties Thermal diffusion in lithium niobate crystals Relaxation phenomena in lithium niobate crystals Electric fields in lithium niobate crystals Electric effect and relaxation polarization of lithium niobate Thermionic emission of lithium niobate single crystals Effective ion charges and spontaneous electric moment of lithium niobate Optical and electro-optical properties of lithium metaniobate single crystals Optical properties of lithium metaniobate Electro-optical effect in dielectric crystals Phenomenological theory of the electro-optical effect Establishment of electro-optic coefficients Specific features of lithium niobate crystals applications in electro-optical devices Nonlinear optical properties of lithium niobate: Elements of nonlinear optics Methods used to establish nonlinear coefficients Relationship of birefringence and phase-matching temperature to lithium niobate crystal composition Criteria for nonlinear-optical quality of crystals Enhancement of SHG in lithium niobate crystals with periodic laminar ferroelectric domains Photoelectrical and photo-refractive properties: Model representations of the photo-refractive effect Occurrence of optical distortion in lithium niobate crystals exposed to cw laser radiation Occurence of optical distortion in lithium niobate exposed to pulsed laser radiation Laser-induced physical effects in lithium niobate Photo-induced distortion of the crystal structure in lithium niobate Optical inhomogeneity of crystals and methods of its investigation Nature of optical inhomogeneity Electrically induced optical inhomogeneity of crystals Doping and heat treatment effects on crystal optical inhomogeneity Methods used to observe optical inhomogeneities in lithium niobate crystals Conclusions References Index
207 citations
"Enhanced Electro-Optic Property in ..." refers background in this paper
...The effects observed could be attributed to the long relaxation time transients and direction dependence of the internal field within congruent LiNbO3 produced by compensating monocharges [15]....
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TL;DR: In this paper, the intrinsic electrical, elastic, optical, and structural properties of antiparallel domain walls in the trigonal ferroelectrics lithium niobate and lithium tantalate were studied.
Abstract: Domains and domain walls are a fundamental property of interest in ferroelectrics, magnetism, ferroelastics, superconductors, and multiferroic materials. Unlike magnetic Bloch walls, ideal ferroelectric domain walls are well accepted to be only one to two lattice units wide, over which polarization and strain change across the wall. However, walls in real ferroelectrics appear to show unexpected property variations in the vicinity of domain walls that can extend over micrometer length scales. This chapter specifically reviews the local electrical, elastic, optical, and structural properties of antiparallel domain walls in the trigonal ferroelectrics lithium niobate and lithium tantalate. It is shown that extrinsic point defects and their clustering play a key role in the observed local wall structure and influence macroscale properties by orders of magnitude. The review also raises broader and yet unexplored fundamental questions regarding intrinsic widths, defect–domain wall interactions, and static versus dynamic wall structure.
205 citations
"Enhanced Electro-Optic Property in ..." refers background in this paper
...It is known [11], [12] that application of an external high electric field shifts the Li+ and Nb5+ ions to the opposite lattice positions and thus invert the direction of spontaneous polarization....
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