At Zero Point Motion we create low noise chipscale optical inertial sensors by combining photonic integrated circuit (PIC) structures with micro-electro-mechanical systems (MEMS) mechanical structures. Our technology is derived from cavity optomechanics which uses the coupling between optical resonances and mechanical motion to detect picometer to femtometre displacements, producing lower noise readout compared with capacitive devices. Our platform comprises ring resonators with whispering gallery mode resonances, that are evanescently coupled to the motion of MEMS accelerometer and vibratory gyroscope test-mass. We report on progress in realising an integrated device, with both MEMS and PIC structures die-to-die bonded and then packaged with light sources and detectors on-chip.

Here, we report on a CMOS-compatible thulium-doped high power continuous wave (CW) optical amplifier, leveraging large mode-area gain waveguides. The amplifier structure combines a silicon nitride waveguide

above which a sputtered 1250 nm-thick thulium-doped alumina gain layer is deposited. We demonstrate > 220 mW output signal power at center wavelength of 1850 nm inside a 9-cm-long amplifier. Small signal gain of > 15 dB is achieved.

We propose a novel polarization rotator concept using two-dimensional (2D) anisotropic materials, such as molybdenum trioxide, on top of 3 µm silicon waveguides. The in-plane anisotropic behavior of 500 nm thick MoO3 flake is analyzed and confirmed with Raman spectroscopy.

Silicon waveguides are a promising candidate for integrated nonlinear optics applications. Nonlinear coefficients of Silicon on Insulator (SOI) waveguides have been previously measured using techniques such as Z-scan, D-scan, Four Wave Mixing (FWM) and Self-phase modulation. However, they have several drawbacks such as they operate at high power or are cumbersome to setup and require multiple measurements to determine all the coefficients. In this work, we develop a direct and single measurement technique to characterize the nonlinear processes in SOI waveguides. This is achieved by employing a heterodyne interferometric technique to accurately measure minute nonlinear response. The measured nonlinear amplitude and phase shifts at 1550 nm wavelength are fit to extract third-order nonlinear coefficients of Two-photon absorption, Kerr nonlinear index, Free carrier absorption and Free carrier dispersion. The obtained coefficients for SOI waveguides are close to that found in literature measured using the above mentioned techniques. The advantages of this method include easy interpretation of the output signal and relatively low power of operation. It is especially advantageous for studying materials such as Phase Change Materials (PCM) in which phase changes occur dynamically. This aspect is quite promising for characterizing emerging materials for integrated photonics applications.

Ray-wave correspondence has proven a powerful tool in mesoscopic optics, in particular in the description of deformed microdisc cavities with a versatile application potential ranging from microlasers to sensors. New material classes such as graphene-based systems have enriched the field by adding Dirac Fermion optics as well as anisotropic material properties as further system parameters. The trigonally warped dispersion relation in bilayer-graphene billiards generalizes the concept of birefringence and opens unconventional ways of trajectory control in the interplay of dispersion relation and the cavity geometry as we illustrate in this contribution.