Subsurface disorder and electro-optical properties of proton-exchanged LiNbO3 waveguides produced by different techniques

Кострицкий, С. М.; Korkishko, Yu. N.; Fedorov, V. A.; Mitrokhin, V. P.; Sevostyanov, О. G.; Chirkova, I. М.; Stepanenko, Oleksandr; Micheli, Marc de

doi:10.2971/jeos.2014.14055

Cited by 10 publications

(22 citation statements)

References 19 publications

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“…37 Soft Proton Exchange (SPE) is an interesting alternative to get, with one fabrication step only, waveguides presenting a surface index increase in the range from 3×10 -2 to 5×10 -2 . 38 Electro-optical operation with surface SPE waveguide is much easily achievable than with RPE waveguides; 39 moreover, higher changes of refractive index resulted in less bending losses 40 and higher nonlinear efficiency.…”

Section: It Stimulates Development Of Alternative Poling Techniques Smentioning

confidence: 99%

Periodic domain patterning by electron beam of proton exchanged waveguides in lithium niobate

Chezganov

Vlasov

Neradovskiy

et al. 2016

Applied Physics Letters

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International audienceFormation of domain structure by electron beam irradiation in congruent lithium niobate covered by surface dielectric layer with planar and channel waveguides produced by Soft Proton Exchange (SPE) process has been studied. Formation of domains with arbitrary shapes as a result of discrete switching has been revealed. The fact was attributed to ineffective screening of depolarization field in the crystals presenting a surface layer modified by the SPE process. The dependences of the domain sizes as a function of the dose and the distance between irradiated areas have been measured. Finally, we have demonstrated that electron beam patterning using surface resist layer can produce high quality periodical poling after channel waveguide fabrication. Second harmonic generation with normalized nonlinear conversion efficiency up to 48%/(W cm 2) has been achieved in such waveguides

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Section: It Stimulates Development Of Alternative Poling Techniques Smentioning

confidence: 99%

Periodic domain patterning by electron beam of proton exchanged waveguides in lithium niobate

Chezganov

Vlasov

Neradovskiy

et al. 2016

Applied Physics Letters

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“…The confocal microscope integrated into the Raman spectrometer, along with the precision and repeatability of the computer-controlled To determine the phase composition of the waveguides, we took into account the data provided by Raman spectroscopy, knowing that each H x Li 1−x NbO 3 phase has a specific spectrum [9][10][11][12]. Proton exchange influences both vibration modes in Raman spectra, causing intensity reduction of some of the Raman lines, the appearance of new ones, and the appearance of disorder-induced broadening of some Raman bands [9][10][11][12][13][14][15][16][17][18]. The Raman spectra were measured with a LabRAM HR800 spectrometer (Horiba Scientific, Jobin Yvon S.A.S.…”

Section: Samples Fabrication and Index Profiles Reconstructionmentioning

confidence: 99%

“…It is worth noting that the "paraelectric band" at 690 cm −1 is a specific feature of the β i -phases [9,10,[12][13][14][15][16]. For example, in Proton Exchange (PE) waveguides with β iphases, the double peak (630 and 690 cm −1 ) is observed [9,[12][13][14]17].…”

Section: Raman Spectroscopymentioning

confidence: 99%

“…Various methods were used to study the H x Li 1−x NbO 3 phases in proton-exchanged LiNbO 3 optical waveguides: X-ray diffraction, M-lines mode spectroscopy, secondary ion mass spectrometry, thermo-gravimetric analysis, differential scanning calorimetry, forward recoil spectrometry, Rutherford backscattering spectrometry, Raman spectroscopy, IR reflection spectroscopy, IR absorption spectroscopy, and UV-VIS absorption spectroscopy . The existence of six to seven phases of H x Li 1−x NbO 3 (depending on the crystallographic orientation of the main surface of the crystal plate) has been established in waveguides fabricated using various proton exchange techniques, including Proton Exchange, Annealed Proton Exchange, Soft Proton Exchange, Vapor-phase Proton Exchange, and High Index Soft Proton Exchange [9,10,15,19,22,25,27]. The specific Raman and IR reflection/absorption spectra are observed for each phase [9][10][11][12][13][14][15][16][17]19,21,24].…”

Section: Introductionmentioning

confidence: 99%

“…The existence of six to seven phases of H x Li 1−x NbO 3 (depending on the crystallographic orientation of the main surface of the crystal plate) has been established in waveguides fabricated using various proton exchange techniques, including Proton Exchange, Annealed Proton Exchange, Soft Proton Exchange, Vapor-phase Proton Exchange, and High Index Soft Proton Exchange [9,10,15,19,22,25,27]. The specific Raman and IR reflection/absorption spectra are observed for each phase [9][10][11][12][13][14][15][16][17]19,21,24]. Therefore, for identification of any H x Li 1−x NbO 3 phase in waveguides fabricated by other techniques, such as the case of our HiVac-VPE [1][2][3] or Reverse Proton Exchange [24], it is sufficient to use optical spectroscopy data.…”

Section: Introductionmentioning

confidence: 99%

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Phase Composition of HiVac-VPE Lithium Niobate Optical Waveguides Identified by Spectroscopic Investigations

Rambu,

Kostritskii,

Fedorov

et al. 2024

Materials

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High-index contrast lithium niobate waveguides, fabricated by the High Vacuum Vapor-phase Proton Exchange (HiVac-VPE) technique, are very promising for increasing both the optical nonlinear and electro-optical efficiencies of photonic integrated devices. So as to play this role effectively, it is mandatory to know the crystallographic phase composition of waveguides and the position of protonated layers for appropriate tailoring and optimization based on the intended applications. In addition, the estimation of structural disorder and electro-optical properties of the waveguides are also of high interest. Benefiting from Raman spectroscopy, IR reflection, IR absorption, and UV-VIS absorption, the HxLi1−xNbO3 phase compositions, as well as the structural disorder in waveguides, were determined. Based on experimental data on the shift of the fundamental absorption edge, we have quantitatively estimated the electro-optic coefficient r13 in as-exchanged waveguides. The electro-optical properties of the waveguides have been found to be depending on the phase composition. The obtained results allow for reconsidering the proton exchange fabricating process of photonic nonlinear devices and electro-optic modulators based on high-index contrast channel waveguides on the LiNbO3 platform.

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UV laser-induced poling inhibition in proton exchanged LiNbO $$_{3}$$ 3 crystals

et al. 2017

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distortion of the ideal domain shape and size thus making fabrication of fine domains challenging [3].Poling inhibition (PI) induced by UV laser irradiation [6,7] in congruent (CLN) and MgO-doped LN can overcome the limitation of EFP by reducing the aspect ratio of the inverted domains allowing for the fabrication of finer domain structures. This method is capable of producing domains with a moderate depth (a few microns below the surface) that can be controlled, to some extent, by the UV laser exposure [8]. UV laser irradiation of the +z polar surface of the crystal results in a local increase of the coercive field by causing migration of lithium ions due to (1) diffusion in the temperature gradients [9] and (2) drift in the pyro-electric field [10]. Consequently, a uniform electric field applied along the z direction will invert the inherent polarisation of the crystal everywhere apart from the volume that has been affected by the UV laser irradiation, which remains poling inhibited. The depth of the PI domains suggests that such structures will be suitable for optical waveguide systems; therefore, it is important to investigate whether poling inhibition is applicable with established waveguide fabrication methods.In this paper, we are investigating the impact of the UVinduced PI procedure on proton exchanged (PE) waveguides, which are fabricated in z-cut LN substrates. Proton exchange is a well-established method for the fabrication of low-loss waveguides, which are resistive to photorefractive damage [11]. PE waveguides are formed by the replacement of lithium ions with protons from a benzoic acid melt (up to a depth of ∼1 µm), which increases the extraordinary refractive index of the crystal [12,13]. The main question that this work attempts to address is whether the UV laser irradiation will produce sufficient coercive field contrast for selective poling, as in the case of poling inhibition of undoped crystals [6,7]. Here, we present Abstract The applicability of the UV laser-induced poling inhibition method for ferroelectric domain engineering in proton exchanged lithium niobate planar waveguides is investigated. Our results indicate that intense UV irradiation of proton exchanged lithium niobate samples can, indeed, produce poling inhibited domains in this material under certain irradiation conditions. However, there is strong indication that the temperature gradient that is formed during UV irradiation modifies the local proton concentration leading to changes in the refractive index profile of the original planar waveguide.

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Subsurface disorder and electro-optical properties of proton-exchanged LiNbO3 waveguides produced by different techniques

Cited by 10 publications

References 19 publications

Periodic domain patterning by electron beam of proton exchanged waveguides in lithium niobate

Periodic domain patterning by electron beam of proton exchanged waveguides in lithium niobate

Phase Composition of HiVac-VPE Lithium Niobate Optical Waveguides Identified by Spectroscopic Investigations

UV laser-induced poling inhibition in proton exchanged LiNbO $$_{3}$$ 3 crystals

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