Daivid Fowler

ORCID: 0000-0003-4576-5819
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About
Contact & Profiles
Research Areas
  • Photonic and Optical Devices
  • Semiconductor Lasers and Optical Devices
  • Advanced Photonic Communication Systems
  • Photonic Crystals and Applications
  • Semiconductor Quantum Structures and Devices
  • Advanced Fiber Laser Technologies
  • Advanced Fiber Optic Sensors
  • Optical Network Technologies
  • Quantum and electron transport phenomena
  • Advanced Optical Imaging Technologies
  • Nanowire Synthesis and Applications
  • Optical Coherence Tomography Applications
  • Advanced Optical Sensing Technologies
  • Optical Coatings and Gratings
  • Neural Networks and Reservoir Computing
  • Spectroscopy and Laser Applications
  • Advanced MEMS and NEMS Technologies
  • Terahertz technology and applications
  • Physics of Superconductivity and Magnetism
  • Quantum chaos and dynamical systems
  • GaN-based semiconductor devices and materials
  • Photorefractive and Nonlinear Optics
  • Quantum, superfluid, helium dynamics
  • Nonlinear Dynamics and Pattern Formation
  • Gyrotron and Vacuum Electronics Research

CEA LETI
2015-2024

CEA Grenoble
2015-2024

Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2015-2024

Université Grenoble Alpes
2015-2024

Institut polytechnique de Grenoble
2014-2023

Centre de Nanosciences et de Nanotechnologies
2023

Institut des Nanotechnologies de Lyon
2019

Centre National de la Recherche Scientifique
2010-2016

Université Paris-Sud
2010-2011

Engineering and Physical Sciences Research Council
2011

In this work, we present two-dimensional beam steering in the near-infrared using a SiN integrated circuit, containing optical phased arrays. Beam was achieved over range of 17.6° × 3°, at fixed wavelength 905 nm. The first dimension steered via phase differences between array channels. second accessed by actively switching various sub-devices output diffraction gratings with different periods. characterisation performed on wafer-level test station.

10.1364/oe.27.005851 article EN cc-by Optics Express 2019-02-15

Silicon photonics is one of the most prominent technology platforms for integrated and can support a wide variety applications. As we move towards mature industrial core technology, present integration silicon nitride (SiN) material to extend capabilities our platform. Depending on application being targeted, have developed several strategies incorporation SiN. We these processes, as well key components dedicated In particular, use SiN athermal multiplexing in optical transceivers datacom...

10.3390/app9020255 article EN cc-by Applied Sciences 2019-01-11

We present the design procedure and experimental results of thermally tunable double ring resonators for integrated wavelength division multiplexing applications. A detailed analytical model specific rings is described, a modified racetrack geometry using Bezier bends used to reduce bending loss. demonstrate devices with free-spectral-range up 2.4 THz (19 nm) around 1550 nm nonadjacent channel rejection higher than 35 dB. The also presented doped silicon heaters, allowing device be as filter...

10.1109/jphot.2017.2662480 article EN cc-by-nc-nd IEEE photonics journal 2017-02-01

This paper aims to present the design and achieved results on a CMOS electronic photonic integrated device for low cost, power, transparent, mass-manufacturable optical switching. An unprecedented number of components (more than 1000), each individually electronically controlled, allows realization transponder aggregator which interconnects up eight transponders four direction colorless-directionless-contentionless ROADM. Each supports 12 200-GHz spaced wavelengths, can be independently...

10.1109/jstqe.2016.2547322 article EN IEEE Journal of Selected Topics in Quantum Electronics 2016-03-29

The field of near-eye see-through devices has recently received significant media attention and financial investment.However, demonstrated to date suffer from practical limitations resulting the conventional optics on which they are based.Potential manufacturers seek surpass these using novel optical schemes.In this paper, we propose such a potentially disruptive technology that may be used for application.Conceptually, our scheme is situated at interface geometric incoherent refractive...

10.1364/optica.5.001200 article EN cc-by Optica 2018-10-04

The availability of low-loss optical interfaces to couple light between standard fibers and high-index-contrast silicon waveguides is essential for the development chip-integrated nanophotonics.Input output couplers based on diffraction gratings are attractive coupling solutions.Advanced grating coupler designs, with Bragg or metal mirror underneath, low-and high-index overlays, multi-level multi-layer layouts, have proven less useful due customized complex fabrication, however.In this work,...

10.1364/oe.27.026239 article EN cc-by Optics Express 2019-08-30

Single-mode optical coupling between fiber and photonic integrated circuit (PIC) requires precision alignment bonding, significantly adds to the cost of packaging. This article describes how a pair micro-lens arrays—one on Si-PIC other fiber-array—can be used achieve fiber-to-PIC grating-coupling with an insertion-loss 1.7 dB (i.e., efficiency 68%) at 1300 nm, 1 tolerance <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math...

10.1109/lpt.2017.2757082 article EN IEEE Photonics Technology Letters 2017-10-02

Abstract Three dimensional sensing is essential in order that machines may operate and interact with complex dynamic environments. Solid-state beam scanning devices are seen as being key to achieving required system specifications terms of range, resolution, refresh rate cost. Integrated optical phased arrays fabricated on silicon wafers a potential solution, but demonstrated system-level performance currently rely expensive widely tunable source lasers. Here, we combine nitride photonics...

10.1038/s44172-024-00224-1 article EN cc-by Communications Engineering 2024-06-04

We experimentally demonstrate beam steering in an optical phased array (OPA) featuring a mixture of individual and cascaded phase modulator architecture embedded the binary splitter tree. show equivalent forming 16 channel OPA with separate applied voltages 16ch 6 control voltages. A 32ch 10 is also demonstrated. These results illustrate flexible means designing significantly fewer electrical connections than count, while minimizing impact waveguide errors on output quality.

10.1109/jlt.2022.3154971 article EN Journal of Lightwave Technology 2022-02-28

A silicon photonics platform that uses a CMOS foundry line is described. Fabrication process following modular integration scheme which leads to flexible platform, allowing different device combinations. complete library demonstrated for 1310 nm applications with state of the art performances. PDK includes specific photonic features and compatible commercial EDA tools has been developed an MPW shuttle service. Finally evolutions such as offer extension 1550 or new modules introduction are presented.

10.1117/12.2228744 article EN Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE 2016-05-13

We report ultra-low propagation losses in silicon sub-micrometric waveguides on a 200 mm CMOS compatible photonics platform. show median C-band (O-band) as low 0.1 dB/cm and 0.7 (0.14 1.1 dB/cm) monomode rib strip waveguides, respectively, thanks to H2 smoothing annealing. In addition the significant loss reduction, we that performance characteristic of main passive active components platform are preserved or even improved by process.

10.1109/jlt.2020.3030123 article EN Journal of Lightwave Technology 2020-10-12

We present the wafer-level characterization of a 256-channel optical phased array operating at 1550 nm, allowing sequential testing different OPA circuits without any packaging steps. Using this, we establish that due to random fabrication variations, nominally identical must be individually calibrated. With this constraint in mind, methods significantly reduce time needed calibrate each circuit. In particular, show for an scale, genetic optimization algorithm is already >3x faster than...

10.1364/oe.464540 article EN cc-by Optics Express 2022-07-19

We study the effects of dissipation on electron transport in a semiconductor superlattice with an applied bias voltage and magnetic field that is tilted relative to axis. In previous work, we showed that, although fields are stationary, they act like terahertz plane wave, which strongly couples Bloch cyclotron motion electrons within lowest miniband. As consequence, exhibit unique type Hamiltonian chaos, creates intricate mesh conduction channels (a stochastic web) phase space, leading large...

10.1103/physreve.77.026209 article EN Physical Review E 2008-02-12

Integrated laser sources compatible with microelectronics represent currently one of the main challenges for silicon photonics. Using Smart Cut<sup>TM</sup> technology, we have fabricated first time 200 mm optical Germanium-On-Insulator (GeOI) substrates which consist a thick layer germanium (typically greater than 500 nm) on top buried oxide (around 1 µm). From this, suspended microbridges efficient Bragg mirror cavities. The high crystalline quality Ge should help to avoid mechanical...

10.1117/12.2079393 article EN Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE 2015-02-27

We exploit the modal confinement properties of metal-metal ridge waveguides to investigate effect reducing thickness active laser cores in both terahertz and mid-infrared quantum cascade lasers. Devices with regions over 55 times thinner than free-space emission wavelength are demonstrated. They show only a modest increase threshold current density compared conventional-thickness devices. The limited is possibly due parasitic channel addition radiative channel. These structures could be...

10.1063/1.3560980 article EN Applied Physics Letters 2011-03-07

We propose a procedure for characterizing fabrication deviations within chip and among different chips in wafer silicon photonics technology. In particular, independent measurements of SOI thickness waveguide width can be mapped through the wafer, allowing precise non-destructive characterization how these variations are distributed along surface wafer. These critical most wavelength-dependent integrated devices, like microring resonators, filters, etc. also show that technique allows...

10.1364/oe.24.006265 article EN cc-by Optics Express 2016-03-11

Currently, one of the main challenges in field silicon photonics is fabrication efficient laser sources compatible with microelectronic technology. An alternative to complexity integration group III-V compounds advancing from high tensile strains applied germanium leading improved emission properties by transforming material an indirect a direct bandgap semiconductor. Theory predicts this transformation occurs at around 4.7% uniaxial strain or 2.0% bi-axial strain. Here, we report on...

10.1117/12.2212597 article EN Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE 2016-03-14

We study the conductivity of a two-dimensional electron gas in modulation-doped n-type ${\mathrm{GaAs}}_{1\ensuremath{-}y}{\mathrm{N}}_{y}/(\mathrm{AlGa})\mathrm{As}$ quantum well heterostructures. find that nature electrical conduction ${\mathrm{GaAs}}_{1\ensuremath{-}y}{\mathrm{N}}_{y}$ channel is band-like or hopping-like depending on N content, carrier concentration, and temperature. show when there sufficient concentration channel, occurs through extended band states...

10.1103/physrevb.69.153305 article EN Physical Review B 2004-04-15

We show that the manipulation of band structure GaAs by incorporation a small amount N provides powerful means tailoring dynamics conduction electrons. observe and model theoretically strong negative differential velocity (NDV) effect occurs when electrons are accelerated an electric field in highly nonparabolic Ga(AsN). The NDV is fundamentally different from occurring superlattice Bloch oscillators transferred electron devices, potential interest for emitters detectors high-frequency radiation.

10.1103/physrevb.72.033312 article EN Physical Review B 2005-07-15

We show that GHz acoustic waves in semiconductor superlattices can induce THz electron dynamics depend critically on the wave amplitude. Below a threshold amplitude, drags electrons through superlattice with peak drift velocity overshooting produced by static electric field. In this regime, single perform drifting orbits frequency components. When amplitude exceeds critical threshold, an abrupt onset of Bloch-like oscillations causes negative differential velocity. The also affects...

10.1103/physrevb.81.235313 article EN Physical Review B 2010-06-09

Providing host Application-specific integrated circuit (ASIC) (e.g., microprocessors, switches, or field-programmable gate array (FPGAs)) with terabit per second optical transmission capabilities has emerged as a new requirement in exascale cloud data centers and high-performance computing. The combination of silicon photonics (Si-Phot) 3-D interconnecting technologies stands unique solution for fulfilling this need while addressing the key factors success that are more Gb/s/cm <sup...

10.1109/tcpmt.2016.2514320 article EN IEEE Transactions on Components Packaging and Manufacturing Technology 2016-01-25

Terahertz frequency photonic-crystal quantum cascade lasers allow directional and controllable surface emission while at the same time functioning efficiently well above liquid nitrogen temperature. Through an in-depth understanding of mechanism underlying emission, we demonstrate optimized devices with significantly reduced absolute threshold currents. We are able to reduce device area by more than a factor two, maintaining angularly narrow, single-lobed divergence ≈10°×10°. The emit...

10.1063/1.3489941 article EN Applied Physics Letters 2010-09-27

Various aspects of grating coupler development are presented to illustrate how the performance and yield this key component our silicon photonics platform has improved over recent years. The device design concept, fabrication testing discussed in order give a more general insight into challenges faced increasing maturity level platforms. In particular, we will highlight some areas which tools solutions developed for CMOS electronics industry have proven inapplicable case photonics, requiring...

10.1117/12.2511845 article EN 2019-03-04

Near-eye displays have become a technology of high interest for Augmented, Virtual and Mixed reality due to the unique immersive experience they provide user. The majority these devices use macroscopic optical elements that make them bulky heavy. Our team has proposed disruptive near-eye display concept uses self-focusing effect project an image user's retina. To form image, emissive points are generated from dense photonic integrated circuit embedded within lens pair smart glasses. In this...

10.1117/12.2649858 article EN 2023-03-16
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