Short reach communication systems, such as datacenters and access networks, exhibit steep capacity growth and require opto-electronic technologies with small size, low complexity, and low power consumption. Here, we demonstrate large-scale arrays of reflective surface normal electroabsorption modulators (SNEAMs). With very small active volumes, SNEAMs enable ultra-wide electro-optic bandwidth (>>65 GHz). We show modulation at 25 Gbit/s with 1 V-pp drive voltage on packaged SNEAMs and ultra-high bit-rate modulation at 107 Gbit/s with bare chips. These modulators are polarization-independent and have very low total input/output coupling loss of 0.7 dB to single-mode-fibers. We package SNEAM arrays with arrayed waveguide gratings into wavelength division multiplexing transmitters. Due to their broad wavelength range of modulation, SNEAMs do not need power hungry wavelength tuning or locking systems. Future co-integration of SNEAM arrays with low-power electronic driver arrays will enable high-capacity, low-power electro-optic engines.

We designed, fabricated and tested an optical hybrid that supports an octave of bandwidth (900-1800 nm) and below 4-dB insertion loss using multiplane light conversion. Measured phase errors are below 3-degree across a measurement bandwidth of 390 nm.

We demonstrate arrays of surface-normal electroabsorption modulators with ultrawide bandwidth (>>65 GHz), polarization insensitive response and ultralow total coupling loss to single-mode-fibers (0.7 dB). We show modulation up to 107 Gbit/s and packaging with arrayed-waveguide-gratings.

We demonstrate digital turbulence compensation using a 12-spatial mode digital coherent receiver with a multimode preamplifier that provides a 6-dB sensitivity improvement. This combination acts similarly to ideal lossless adaptive optics. Coherent superposition of 12 spatial-modes reduced median BER from 0.1 to 1×10-5 compared to traditional single-mode detection.

We show mode-multiplexed transmission over individual mode groups up to 9 groups of a 27 km long graded-index multimode fiber. We also investigate transmission distances up to 500 km using a recirculating loop arrangement for the first 6 mode groups using QPSK and 16-QAM signals.

Chip-scale OCT has the potential to enable non-invasive and continuous sensing of our surrounding environment and internal physiology. We report our recent work building a swept-source system with >90dB sensitivity at 100kHz using PLC technology.

Record high sensitivity of 90dB is achieved in a chip-scale SS-OCT system. A PLC interferometer, on-chip balanced diode pair, and ball lens coupled MEMS mirror form an ultra-compact optical engine for 3D imaging.

We demonstrate mode-multiplexed 90×90 MIMO transmission over all nine mode groups of a 26.5-km graded-index multimode fiber span, achieving a record spectral efficiency of 202 bit/s/Hz.

We show mode-multiplexed transmission over the 6 th mode group of a 50-μm graded-index multimode fiber using a multi-plane light conversion device, for transmission distances up to 90 km.

We built and characterized a pair of 45-mode multi-plane light conversion mode multiplexers. Insertion losses of 4-6dB was measured for all ports.

Fast and simple optical filtering is a prerequisite for low-cost passive optical networking using multiple wavelengths to scale to higher capacity. We demonstrate a simple electro-magnetically tuned optical filter capable of tuning across more than 700 GHz of optical spectrum in under 1 ms with low optical loss. We show successful transmission of 10.3-Gb/s modulated signals through the filter with no additional impairments. The device is straightforward to fabricate and assemble and, therefore, offers potentially low cost.

We show 72×72 MIMO based transmission over a 2 km long 50μm graded-index multimode fiber with a spectral efficiency of 72 bitls/Hz.

We design and build a mode scrambler modes based on multiplane light conversion that completely inverts the first 10 spatial modes of of a graded index multimode fiber.

Electrical resistivity measurements of the superconductor La1.80sr0.20CuO4-δ over a Wide range of temperatures and oxygen concentration, together with the analysis of superconducting properties of the material, indicate that the ceramic superconductors are high < materials in the clean limit. The granular superconducting behavior is determined by the oxygen content.