Massachusetts Institute of Technology

Carlos Andres Rios Ocampo

Juejun Hu

Derek Kita

Tian Gu

Mikhail Shalaginov

Yifei Zhang

Xiaoming Qiu

Reversible phase-change materials (PCMs) can be added to or incorporated into meta-lenses, wave plates, waveguides, gratings, and other optical components to form active optical devices with controllable and adjustable optical characteristics. Local heating can be used to induce solid-state phase changes and large refractive index changes in the PCMs. The phase and index changes can provide large changes in the device's optical characteristics. Optical devices with PCM can be used for imaging applications, orbital angular momentum control, photonic integrated circuits and optical communication systems, beam steering, and other application.

Optical devices with phase-change materials

We disclose an on-chip photonic spectroscopy system capable of dramatically improving the signal-to-noise ratio (SNR), dynamic range, and reconstruction quality of Fourier transform spectrometers. Secondly, we disclose a system of components that makes up a complete on-chip RF spectrum analyzer with low-cost and high-performance.

High-performance on-chip spectrometers and spectrum analyzers

An optical coherence tomography (OCT) engine includes a digital Fourier-Transform (dFT) spectrometer, a tunable delay line, and a high-speed optical phased array (OPA) scanner integrated onto a single chip. The broadband dFT spectrometer offers superior signal-to-noise ratio (SNR) and fine axial resolution; the tunable delay line ensures large imaging depth by circumventing sensitivity roll-off; and the OPA can scan the beams at GHz rates without moving parts. Unlike conventional spectrometers, the dFT spectrometer employs an optical switch network to retrieve spectral information in an exponentially scaling fashion&#x2014;its performance doubles with every new optical switch added to the network. Moreover, it also benefits from the Fellgett's advantage, which provide a significant SNR edge over conventional spectrometers. The tunable delay line balances the path length difference between the reference and sample arms, avoiding any need to sample high-frequency spectral fringes.

Growing community of inventors

Somerville, MA, United States of America

Carlos Andres Rios Ocampo