Hiring Institution
École Centrale de Lyon (EC Lyon)

PhD-Awarding Institutions
École Centrale de Lyon (EC Lyon)
The University of Sydney (USYD)

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Option 1

Pure-Quartic Solitons in Integrated photonic platform for telecom band operation

Optical solitons are wave packets that can propagate without changing shape. These pulses have underpinned numerous applications, ranging from telecommunications and spectroscopy to ultrashort pulse generation. Conventionally, solitons rely on the balance between the Kerr nonlinearity and negative second-order dispersion (β₂< 0) as it is the dominant dispersion effects in typical optical waveguides. However, the energy of such solitons is fundamentally capped by the soliton area theorem leaving important high-energy, nonlinear applications out of reach.

The Usyd group has recently observed and generated a novel class of optical solitons, called pure-quartic soliton (PQS). Unlike conventional solitons, they arise from the interplay between Kerr nonlinearity and negative fourth-order dispersion (β₄ < 0). Subsequent studies showed that PQSs can have substantially higher energy – by a few orders of magnitude, than conventional solitons, while offering the same coherence and stability.

This project aims to build on these recent discoveries, and to transfer this new physics of PQSs to integrated photonic platforms in the telecom band (~ 1.5 µm), i.e Microring resonators or dispersion engineered waveguides in Lithium Niobate or Si3N4 recently developed by INL/ CEA-Leti. The direct on-chip generation of high-energy pulses, by using the enhancement, inherent to PQSs, instead of adding technological complexity, could unlock new nonlinear capabilities in integrated photonics.

The work will have elements of: (i) theory/waveguide design and (ii) optical characterization and device benchmarking using both experimental and numerical tools.

There will be opportunities to travel and interact with our partners on a national and international level (both Europe/France and Australia) including European industry (CEA-LETI and others).

Option 2

Pure-Quartic Solitons in Integrated photonic platform for Mid-Infrared applications

Many applications such as spectroscopy, gas detection, environmental surveillance, free space communication etc require bright sources in the mid-infrared (mid-IR – in the molecular fingerprint region beyond 3 um).

The INL/CEA-Leti consortium (in collaboration with Australian Universities) has already demonstrated the ability to generate broad Mid-IR supercontinuum based on soliton propagation (solitons generally rely on the balance between the Kerr nonlinearity and negative second-order dispersion β₂< 0) in dispersion engineered integrated SiGe waveguides.

However, the energy of such solitons is fundamentally capped by the soliton area theorem leaving important high-energy, nonlinear applications out of reach.

The Usyd group has recently observed and generated a novel class of optical solitons, called pure-quartic soliton (PQS). Unlike conventional solitons, they arise from the interplay between Kerr nonlinearity and negative fourth-order dispersion (β₄< 0). Subsequent studies showed that PQSs can have substantially higher energy – by a few orders of magnitude, than conventional solitons, while offering the same coherence and stability.

This project aims to build on these recent discoveries, and to transfer this new physics of PQSs to the SiGe integrated photonic platform in the Mid-IR band (between 3 and 13 µm) developed by INL/ CEA-Leti. The direct on-chip generation of high-energy pulses, by using the enhancement, inherent to PQSs, instead of adding technological complexity, could unlock new nonlinear capabilities and applications in this wavelength range.

The work will have elements of: (i) theory/waveguide design and (ii) optical characterization and device benchmarking using both experimental and numerical tools.

There will be opportunities to travel and interact with our partners on a national and international level (both Europe/France and Australia) including European industry (CEA-LETI and others).

Option 3

Pure-Quartic Solitons in Integrated active photonic crystal structures

Optical solitons are wave packets that can propagate without changing shape1. These pulses have underpinned numerous applications, ranging from telecommunications and spectroscopy to ultrashort pulse generation. Conventionally, solitons rely on the balance between the Kerr nonlinearity and negative second-order dispersion (β₂< 0) as it is the dominant dispersion effects in typical optical waveguides. The Usyd group has recently observed and generated a novel class of optical solitons, called pure-quartic soliton (PQS). These arise from the interplay between Kerr nonlinearity and negative fourth-order dispersion (β₄ < 0), providing substantially higher pulse energy – by a few orders of magnitude, than conventional solitons, while offering the same coherence and stability.

This project aims to build on these recent discoveries, and to transfer this new physics of PQSs to integrated photonic platforms in the telecom band (~ 1.5 µm) that include an active gain medium. Planar III-V photonic crystals will be explored to that aim, as they allow for a fine control of the underlying photonic dispersion by simply adjusting the position of the air holes that surround the linear defect. Such structures have been used to create slow light regimes conducive to enhance optical nonlinearities, but could also promote the existence of these PQSs. III-V Quantum wells will be combined with these new dispersion regimes, so as to investigate the opportunities of such promising photonic design structures for the generation of short optical pulses within compact platforms.

The work will have elements of: (i) theory/photonic design, (ii) device fabrication in clean room environment and (iii) optical characterization and device benchmarking using both experimental and numerical tools.

There will be opportunities to travel and interact with our partners on a national and international level (both Europe/France and Australia) including European industry (CEA-LETI and others).

Christian Grillet
Christelle Monat
Antoine Runge
Prof. Martijn de Sterke

Physics, Photonics, Nonlinear Optics