Experimental demonstration of (1+1)D self-confinement and breathing soliton-like propagation in photorefractive crystals with strong optical activity

Screening-photovoltaic bright solitons in lithium niobate and associated single-mode waveguides

“…Bright solitons are much more stable than dark solitons and offer the simplest way to photo-induce slab and channel waveguides. The application of intense biases has been already tested 9,10 with other photorefractive materials, and in this letter will be applied to induce bright solitons in congruent undoped LiNbO 3 .…”

Photorefractive solitons

“…Since their first experimental observation, PR solitons have been the subject of very intense experimental and theoretical studies. They have been observed not only in commonly used noncentrosymmetric PR crystals such as BTO [32], BSO [33], [34], [113], potassium niobate [35], [114], [36], and SBN, but also in biased semiconductors [37], [115], [38] and even centrosymmetric crystals [39]. These studies resulted in the obser- vation of a great variety of interesting features.…”

“…These studies resulted in the obser- vation of a great variety of interesting features. They include such effects as the formation of dark spatial solitons [40]- [42], self-bending of solitons [25], [26], soliton propagation in optically active crystal [34], [113], [43], [44], demonstration of waveguiding properties of spatial solitons [45], [116]- [118], or modulational instability of planar wave fronts in PR crystals [46], [47]. As an example, in Fig.…”

Optical Soliton Neural Networks

“…The value of the electric field to bias strongly depends on the crystal type and its electro-optic coefficient: for example, using strontium barium niobate crystals (SBN) which have a very high electro-optic coefficient, the electric field ranges from a few hundred V/cm up to some kV/cm [26]; lithium niobate (LN) has a lower electro-optic coefficient and requires several tens of kV/cm [22]; in materials with high optical activity like Bi 12 SiO 20 (BSO), the applied bias must be as high as 55 kV/cm or higher to induce the light to reach a nonlinear polarization regime and to self-confine [27][28][29]. Chauvet et al [30,31] proposed an interesting innovative solution for the bias application: induce an internal electric field by applying a thermal gradient and take advantage of the pyroelectric effects that some crystals have, for example, LN.…”