Coherent Fiber Optic
This research is organized in three large projects:
spatial division multiplexing (SDM), energy-efficient transmission, and novel
transmission schemes. The SDM project aims at finding efficient transmission
schemes over parallel optical channels. The energy efficiency project involves
close collaborations with the E2 and CSE departments for a holistic view of the
energy consumption of optical links. The novel transmission scheme project includes demonstrations of
frequency comb-based transmission with record spectral efficiency of 11.5
This research utilizes the unique
features of phase-sensitive optical amplifiers - producing nearly no excess
noise and the ability to mitigate transmission fiber nonlinearities.
Significant reach extension in long-haul fiber transmission was demonstrated
using QPSK and QAM signals. Additional benefits of distributed Raman
amplification, few-mode fibers, and processing in highly nonlinear integrated
waveguides are investigated. Very high sensitivity receivers for free-space optical
communication were demonstrated.
focuses on laser frequency comb technology for
applications in fiber-optic communication systems and ultrafast metrology.
Record transmission reach using an integrated frequency comb generator as the
multi-wavelength light source was recently demonstrated. The technology for hybrid
integration with silicon photonics integrated circuits is also being developed.
VCSELs and Optical
Here, vertical-cavity surface-emitting lasers (VCSELs)
and associated technologies for applications in datacom and life science are
being developed. VCSEL-based transmitters with record speed and efficiency were
demonstrated. Dense arrays of high-speed VCSELs enabled record capacity
multicore fiber interconnects. Single-channel speed above 100 Gbps was demonstrated by using multilevel modulation. Heterogeneous integration of hybrid
vertical-cavity lasers on silicon demonstrated the potential of such lasers as
efficient light sources for silicon photonic integrated circuits.
This research focuses on light-emitters from
wide-bandgap materials for ultraviolet and visible wavelengths. Devices such as resonant-cavity
light-emitting diodes and microcavity lasers, from both planar and
nanostructured materials are investigated for applications in solid-state
lighting, visible light communication and medical diagnosis. Novel fabrication
techniques for GaN-based VCSELs, thin-film LEDs, and membrane based emitters
are being developed.
Epitaxy of Novel
The research focuses on epitaxial growth of high
quality dilute-bismides for lasers and bismuth-telluride topological insulator
(TI) for spintronic device applications. The first long-wavelength GaAsBi
quantum well lasers operating at room temperature were demonstrated, as well as
spin injection from GaAs into 3D Bi2Te3 TIs.