Flexible integration of free-standing nanowires into silicon photonics

Abstract

Silicon photonics has been developed successfully with a top-down fabrication technique to enable large-scale photonic integrated circuits with high reproducibility, but is limited intrinsically by the material capability for active or nonlinear applications. On the other hand, free-standing nanowires synthesized via a bottom-up growth present great material diversity and structural uniformity, but precisely assembling free-standing nanowires for on-demand photonic functionality remains a great challenge. Here we report hybrid integration of free-standing nanowires into silicon photonics with high flexibility by coupling free-standing nanowires onto target silicon waveguides that are simultaneously used for precise positioning. Coupling efficiency between a free-standing nanowire and a silicon waveguide is up to ~97% in the telecommunication band. A hybrid nonlinear-free-standing nanowires–silicon waveguides Mach–Zehnder interferometer and a racetrack resonator for significantly enhanced optical modulation are experimentally demonstrated, as well as hybrid active-free-standing nanowires–silicon waveguides circuits for light generation. These results suggest an alternative approach to flexible multifunctional on-chip nanophotonic devices.

Low‐Power Continuous‐Wave Second Harmonic Generation in Semiconductor Nanowires

“…In the NW‐PPC cavity, NWs' SHG is more than two orders of magnitude stronger than the THG in the silicon slab, though they only couple with less than 1% of the cavity mode. Semiconductor NWs have been integrated onto photonic chips to serve as waveguides, couplers, and switchings . Here, with the assistance of a silicon PPC cavity, the power requirement of SHG in NWs is reduced significantly.…”

Threshold reduction and yield improvement of semiconductor nanowire lasers via processing-related end-facet optimization

“…5 Recent progress has led to an increase in efficacy of semiconductor nanowire lasers through both improved nanowire geometry and optimized active region absorption. [6][7][8][9][10][11][12][13][14] In many applications it is necessary to transfer the wires to a structured 15 or lower index substrate such as silica aerogel, 16 indium tin oxide (ITO) 7 or SiO 2 , 17 and, while many efforts have contributed to the improvement of lasing operation, the impact of different nanowire transfer techniques on nanowire geometry and, consequently optical performance has so far not been addressed.…”

Single‐Crystalline Perovskite Microlasers for High‐Contrast and Sub‐Diffraction Imaging

“…The semiconductor nanowires have been integrated as light sources and nonlinear devices into on‐chip photonic circuits . By monitoring the spectrum, nanowire lasers can also be utilized as optical sensors and optical routers . However, despite the reduction of cost and the improvements on flexibility, the device performances in these applications are usually interior to their top‐down fabricated monolithic counterparts …”