Lithium Niobate Optical Waveguides and Microwaveguides

Abstract

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 electrooptical (EO) lithium niobate waveguides throughout the years, from Ti-indiffused waveguides 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-toimplement technique using a circular precision saw to produce thin ridge waveguides or suspended membranes with low losses.

Channel Waveguides in Lithium Niobate and Lithium Tantalate

“…The output near-field profiles imaged by a 40× microscope objective are shown in Figure 11. The near-field beam profiles indicate multimode propagation within the channel, [33] which is consistent with the refractive index contrast (∆n o~0 .1) provided by the lithium tantalate substrate and lithium niobate channels. Numerical simulations were performed using BeamPROP (part of the RSoft Photonics CAD Suite, USA) which is based on a finite difference beam propagation method assuming 10 nm step sizes in the x, y and z directions.…”

Halide Perovskites: Advanced Photovoltaic Materials Empowered by a Unique Bonding Mechanism

“…Perovskites form a wide class of compounds where nearly all atoms of the periodic table can fit into their chemical formula ABX 3 . The most studied perovskites were, for a long time, the oxides (X = O) due to their numerous applications including sonars (piezoelectric PbZr x Ti 1−x O 3 -PZT), [15] photonics (electro-optic LiNbO 3 ), [16] capacitors (dielectric permittivity, BaTiO 3 ), [17] and infrared detectors (pyroelectric LiTaO 3 , PbTiO 3 ). [18] Only very recently, a surge of interest has been stirred focusing on halide perovskites and their potential for optoelectronic devices, most notably at present for PV applications.…”

Tuning between Proper and Hybrid-Improper Mechanisms for Polar Behavior in CsLn2Ti2NbO10 Dion-Jacobson Phases

“…Ferroelectrics are widely used in applications such as sonars and sensors, 1 electrooptics, 2 capacitors, 3 and memory devices, 4 making them materials of significant technological importance. From an academic perspective, the origins of their switchable polarization are fascinating as they hold the key to designing new classes of polar materials.…”