Quantum technologies harness nonclassical features of particles, here, photons, to develop novel, efficient, and precise devices for information processing applications. Superposition, entanglement, as well as the coherent manipulation of quantum states are at the heart of the second quantum revolution (quantum 2.0) which targets the development of secure cryptographic systems, complex computation protocols, and more. Emerging quantum architectures rely on the realistic implementation of photonic schemes which are scalable, resource-efficient, and compatible with CMOS technologies as well as fiber networks. This work demonstrates current schemes utilized for time-/frequency-bin entanglement generation and processing by leveraging existing telecommunications and integrated photonics infrastructures.

Advances in the field of deep learning have been thrilling to witness but come with an increasingly unsustainable appetite for computing resources. Thus, the generality and accuracy of deep learning is also its Achilles’ heel. Novel approaches to computation are therefore needed to address the slowing growth in compute performance and efficiency of electronic hardware in order to keep pace with the rapid advances in deep learning innovation. In this talk, I will present two complementary computing approaches which leverage photonic crossbar arrays and phase-change materials to perform low latency and high efficiency matrix operations for applications in deep learning.

We unraveled a novel optical bistable state in amorphous silicon nanocuboids, featuring an abrupt super-linear jump of scattering intensity during hysteretic switching. The effective intensity dependency reaches 19th power, leading to an nonlinear index n2 as large as 5 μm2/mW, 7-order larger than the bulk value and well explained through coupled electromagnetic and photothermal simulation. Combining the ultralarge super-linear response with dark-field laser scanning microscopy, 3.5-times resolution enhancement was achieved, without any need of temporal/spatial excitation modulation. This hysteresis scattering not only sets a benchmark in optical super-resolution technique, but also suggests further optical signal processing potentials.

We establish a systematic framework of photonic device discovery using a physics-based deep learning approach. The computationally expensive physics simulations are removed from the critical loop to generate data and perform one-time training of the deep learning models. Consequently, the trained deep learning models achieve massive speed up on the iterative design process. Our approach reduces the computational time from days to minutes. Using a silicon power divider as an example, we demonstrate discovery of a spectrum of devices that simultaneously satisfy compact footprints, ultralow losses, ultrawide bandwidth, and exceptional robustness against fabrication randomness.

GeSn alloys are the most promising direct band gap semiconductors to demonstrate full CMOS-compatible laser integration with a manufacturing from Group-IV materials. Since the first demonstration of lasing with GeSn alloys up to 100 K, many researches were devoted to increase the laser operation up to room temperature. We will discuss the band sructure requirements and the practical issues that have to be addressed in order to reach robust gain with increasing temperature. We show that misfit defects managment and strain engineering are key ingredients. For that purpose we developped a GeSn-On-Insulator platform, that combine strain engineering , defective interfacial layer removal and laser resonator designs ad fabrication. Here we show that room temperature lasing, up to 300 K, can be obtained in microdisk resonators fabricated on a GeSnOI layer both with using high Sn-content in the gain medium, e. g. 17% or with applying tensile strain to a layer with lower Sn-content of 14%.

Upgraded particle colliders will require high bandwidth readout capable of withstanding extremely high levels of radiation. Optical links Silicon photonics is a promising solution, but conventional high-speed modulators cannot survive radiation damage. Preliminary results show hardening techniques capable of enduring 1 Grad of total ionizing dose, but without yet demonstrating high speed modulation. Ring resonator modulators were designed with various radiation hardness by design techniques and irradiated. Most promising is a highly doped ring resonator modulator with an 18 GHz bandwidth that survived 300 MRad of total ionizing dose.

In this communication we will present the first semiconductor laser grown on a Si photonics platform in a butt-coupling configuration. A GaSb-based diode laser (DL) was grown on a patterned Si photonics wafer equipped with SiN waveguides. Growth and device fabrication challenges arising from the template architecture were overcome to demonstrate several mW outpower of emitted light in continuous wave operation at room temperature. In addition, around 10% of light was coupled into the SiN waveguides, in good agreement with theoretical calculations. This work paves the way to future on-chip sensors.

Through the combination of nanoscale Mie-resonance and photothermal/thermo-optical effect, plus a nanosecond excitation source that matches the thermal relaxation time of a silicon nanostructure, we demonstrated an ultra-large nonlinear index n2 = 1 um^2/mW, six-orders larger than the value in bulk. Under a confocal laser scanning scheme, unexpected sharp transition of scattering intensity is unveiled, suggesting a rapid temperature transient. The super-continuum wavelength tunability offers high-efficiency excitation among nano-silicon with various sizes. This robust and ultra-large nonlinearity shall be useful in optical switching and super-resolution mapping of semiconductor nanophotonic structures.

Materials and device components necessary to build a mid-infrared platform sensor system will be discussed. The talk will focus on fundamental and technological challenges, along with possible solutions, for the realization of such a platform.

This was conference presentation was presented at Photonics West 2023.

The advent of 300mm fabrication tools and immersion lithography for photonics may change the game and the practical use of ring resonator based devices. We implemented such ring resonators on our 300 mm SOI platform for Silicon photonics using immersion lithography. We show that such technology offers unprecedented level of uniformity and reproducibility within a die but also from die to die. Such performances allowed us to combine and cascade ring resonators to fabricate high rejection filters in Coupled Resonator Optical Waveguide (CROW) configurations. Such high rejection filters are thus very promising candidates for quantum photonics, and more particularly in circuits based on photons pair generation, where pump rejection filters with over 100dB of rejection are needed.