Improvement of liquid crystal tunable lenses with weakly conductive layers using multifrequency driving

A common technique to realize the gradient electric field profile that is required in liquid crystal tunable lenses is the use of a weakly conductive layer. Thanks to this layer, an applied voltage with a certain frequency allows us to obtain a refractive index profile that is required for the lens operation. Due to the limited degrees of freedom, however, it is not possible to avoid aberrations in a weakly conductive layer-based tunable lens for a continuously tunable focal length. In this work, we discuss the use of additional higher frequency components in the voltage signal to reduce the lens aberrations drastically. (C) 2020 Optical Society of Americ

Micro-transfer printing of lithium niobate on silicon nitride

Successful micro-transfer printing of lithium niobate on a silicon nitride platform is demonstrated. A proof of concept electro-optical modulator is fabricated using this hybrid integration method which shows a half-wave voltage-length product VπLπ=5.5 Vcm and insertion losses of 7 dB

High-Efficiency Second Harmonic Generation in Heterogeneously-Integrated Periodically-Poled Lithium Niobate on Silicon Nitride

Wavelength conversion processes such as spontaneous parametric down conversion (SPDC) and optical parametric amplification (OPA) are key elements in integrated quantum optics. On-chip integration of these function-alities would allow for increased performance and huge scaling opportunities. However, CMOS-compatible plat-forms such as silicon and silicon nitride (SiN) lack a $chi$(2) nonlinearity due to their inversion symmetry. This work provides a solution by heterogeneously integrating periodically poled lithium niobate (PPLN) onto SiN waveguides through micro-transfer printing (textmuTP) [1]. The textmuTP method is a scalable back-end process, allowing the fabrication of the photonic integrated circuit to remain CMOS-compatible.info:eu-repo/semantics/publishe

Reliable micro-transfer printing method for heterogeneous integration of lithium niobate and semiconductor thin films

High-speed Pockels modulation and second-order nonlinearities are key components in optical systems, but CMOS-compatible platforms like silicon and silicon nitride lack these capabilities. Micro-transfer printing of thin-film lithium niobate offers a solution, but suspending large areas of thin films for long interaction lengths and high-Q resonators is challenging, resulting in a low transfer yield. We present a new source preparation method that enables reliable transfer printing of thin-film lithium niobate. We demonstrate its versatility by successfully applying it to gallium phosphide and silicon, and provide an estimate of the transfer yield by subsequently printing 25 lithium niobate films without fail.info:eu-repo/semantics/publishe

Pillar-Based High-Yield Heterogeneous Integration of Lithium Niobate and Gallium Phosphide Thin Films

Several established photonic platforms lack a nonzero Pockels and nonlinear coefficient. We developed a micro-transfer printing method to heterogeneously integrate thin-film lithium niobate and gallium phosphide with an experimentally shown transfer yield of near-unity.info:eu-repo/semantics/publishe

Filling the gap of silicon nitride photonic platform functionalities using micro-transfer printing

International audienceIn this work we demonstrate the heterogeneous integration of active devices on the SiN photonic platform using micro-transfer printing and we will discuss the remaining technological challenge

Gold-induced photothermal background in on-chip surface enhanced stimulated Raman spectroscopy

Surface enhanced Raman spectroscopy (SERS) and stimulated Raman spectroscopy (SRS) are well established techniques capable of boosting the strength of Raman scattering. The combination of both techniques (surface enhanced stimulated Raman spectroscopy, or SE-SRS) has been reported using plasmonic nanoparticles. In parallel, waveguide enhanced Raman spectroscopy has been developed using nanophotonic and nanoplasmonic waveguides. Here, we explore SE-SRS in nanoplasmonic waveguides. We demonstrate that a combined photothermal and thermo-optic effect in the gold material induces a strong background signal that limits the detection limit for the analyte. The experimental results are in line with theoretical estimates. We propose several methods to reduce or counteract this background. (C) 2021 Optical Society of Americ

High-Speed Lithium Niobate Modulator on Silicon Nitride using Micro-Transfer Printing

A high-speed modulator on silicon nitride is demonstrated using 2 mm-long micro-transfer printed lithium niobate coupons. This device has a 3-dB bandwidth ANDgt;50GHz, and an insertion loss of 3.3 dB that allowed us to transmit 70 Gb/s.info:eu-repo/semantics/publishe

Heterogeneous integration of a high-speed lithium niobate modulator on silicon nitride using micro-transfer printing

Integrated photonic systems require fast modulators to keep up with demanding operation speeds and increasing data rates. The silicon nitride integrated photonic platform is of particular interest for applications such as datacom, light detection and ranging (LIDAR), quantum photonics, and computing owing to its low losses and CMOS compatibility. Yet, this platform inherently lacks high-speed modulators. Heterogeneous integration of lithium niobate on silicon nitride waveguides can address this drawback with its strong Pockels effect. We demonstrate the first high-speed lithium niobate modulator heterogeneously integrated on silicon nitride using micro-transfer printing. The device is 2 mm long with a half-wave voltage Vπ of 14.8 V. The insertion loss and extinction ratio are 3.3 and 39 dB, respectively. Operation beyond 50 GHz has been demonstrated with the generation of open eye diagrams up to 70 Gb/s. This proof-of-principle demonstration opens up possibilities for more scalable fabrication of these trusted and performant devices.info:eu-repo/semantics/publishe