"UCSB Nanotech Tech Talks | Dr. Renan Moreira, ULL Technologies & Grégoire Coiffard, UCSB"

Renan Moreira, ULL Tech & Grégoire Coiffard, UCSB,

December 5th (Thursday), 12:00pm
Engineering Science Building (ESB), Rm 1001

“Ultra-low Loss Photonic Integrated Circuits Based on Si3N4 Waveguides”
Dr. Renan Moreira, Ultra-low Loss Technologies

Abstract: Photonic integrated circuits (PICs) play a major role in the advancement of optical systems. One of the main constraints of PICs is the high propagation loss of optical waveguides; therefore, achieving “fiber-like” losses on-chip would allow for major improvement in the overall chip performance. ULL technologies’ mission is to commercialize ultra-low loss photonic integrated circuits and provide access to this highly specialized technology. Our disruptive technology will revolutionize photonic systems for communications, computing and sensing. The design of such waveguides and optical circuits requires a balance of numerous tradeoffs between mode-size, bending radius, and footprint, to name a few. Herein, we present the design and fabrication of PICs using our ultra-low loss waveguide platform.

“The Fabrication of 20,000 Pixel Kinetic Inductance Detector Arrays for Near-IR to Visible Astronomy”
Grégoire Coiffard, UCSB

Abstract: Most of the photodetectors used for near-IR to visible astronomy are based on semiconductor materials. Thanks to decades of investment and development, mega-pixel scale arrays are widely available today. These detectors are sensitive to photons that have energy equal to or greater than the semiconductor gap energy, typically on the order of 1 eV (1.2 um) and they are not well suitable for individual photon detection. As an advancement in photodetection technology, we are making arrays where each pixel has an energy gap ~5000x smaller than semiconductor-based technology enabling sensitivity to photons deeper into the IR energies (5 um). They are each sensitive to single photons allowing registration of the photon arrival time and avoiding noise associated with the readout of pixels which did not receive any photons (dark current/read noise). Each pixel is a superconducting resonant circuit, called a Microwave Kinetic Inductance Detector (MKID). Because the energy gap gets smaller as the superconducting transition temperature (Tc) is decreased, we make our MKIDs of superconductors having Tc between 1 K and 0.12 K. So far our biggest MKID photodetector array, currently installed at the Subaru telescope (Mauna Kea, Hawaii), has 20,000 pixels. In this talk, I describe the MKID principles of operation, key array fabrication steps, other important superconductor material properties in addition to Tc and science results from the 20,000 pixel array.

About Renan Moreira, ULL Tech & Grégoire Coiffard, UCSB:

Moreira Biography: Dr. Renan Moreira is a co-founder of Ultra-low Loss Technologies. He has several years of experience in the design and fabrication of photonic devices. His graduate research work focused on the design of ultra-low loss waveguides and their application towards integrated optical delay line circuits. Before Ultra-low Loss Technologies, Dr. Moreira worked as a senior design scientist at Freedom Photonics LLC, where he led several programs in the areas of microwave photonics, PNT device, and tunable lasers for a variety of applications. Dr. Moreira received his PhD and M.S. in electrical engineering from UCSB and a B.S. in electrical engineering from University of Texas at San Antonio.

Coiffard Biography: Grégoire Coiffard graduated from Grenoble Institute of Technology with a specialty in physics and nano-science in 2015. He worked on an instrument for radio astronomy currently installed at the IRAM 30-meter telescope in Spain. In 2016 he joined Mazin Lab at UCSB where he is now working on near-IR to visible superconducting detectors.

Hosted by: Professor Jonathan Klamkin