An InP ring resonator with an experimentally demonstrated quality factor (Q) of the order of 10⁶ is reported for the first time. This Q value, typical for low loss technologies such as silica-on-silicon, is a record for the InP technology and improves the state-of-the-art of about one order of magnitude. The cavity has been designed aiming at the Q-factor maximization while keeping the resonance depth of about 8 dB. The device was fabricated using metal-organic vapour-phase-epitaxy, photolithography and reactive ion etching. It has been optically characterized and all its performance parameters have been estimated. InP waveguide loss low as 0.45 dB/cm has been measured, leading to a potential shot noise limited resolution of 10 °/h for a new angular velocity sensor.

This paper describes a fabrication process for realizing Indium-Phosphide-based photonic-integrated circuits (PICs) with a high level of integration to target a wide variety of optical applications. To show the diversity in PICs achievable with our open-access foundry process, we illustrate two examples: a fully-integrated 20 Gb/s dual-polarization electro-absorption-modulated laser, and a balanced detector composed of avalanche photodiodes for detection of 28 Gb/s optical signals. On another note, datacenters are increasingly relying on hybrid integration of PICs from different technology platforms to increase transmission capacity, while simultaneously lowering cost, size, and power consumption. Several technology platforms require surface coupling rather than the traditional edge coupling to couple the light from one PIC to another. To accommodate the surface-coupling approach in our integration platform, we have developed a strategy to transfer the following optical Input/Output devices into our fabrication process: grating couplers, and vertical mirrors. In addition, we introduced etched facets into the process to improve the usability of our edge-coupling elements. We believe that the additional flexibility in Input/Output interfacing combined with the integration of multiple devices onto one PIC to reduce the number of PIC-to-PIC alignments can contribute significantly to the development of compact, low-cost, and high-performance datacenter modules.

Photonic integrated circuits (PICs) play a key role in a wide range of applications. Very often, the performance of PICs depends strongly on the state of polarization of light. Classically, this is regarded as undesirable, but more and more applications emerge that make explicit use of polarization dependence. In either case, the characterization of the polarization properties of a PIC can be a nontrivial task. We present a way of characterizing PICs in terms of their full Müller matrix, yielding a complete picture of their polarization properties. The approach is demonstrated by carrying out measurements of fabricated PICs.

Solid state LiDAR systems traditionally rely on costly active components for efficient beam scanning. In this study, we propose a cost-effective, purely passive steering approach using apodized slanted grating couplers. Through apodization, we achieve a uniform upward emission profile and enhanced upward transmission. Theoretical calculations indicate successful steering of 91.5$^\circ$x42.8$^\circ$. Experimental results closely match theoretical predictions, validating the capabilities of our passive steering concept. Additionally, the grating couplers, with a length of 3mm, enable a farfield FWHM of 0.026$^\circ$, further enhancing sensing resolution.