Dr. Stephen P. Hegarty Profile

Dr. Stephen P. Hegarty

at Tyndall National Institute

SPIE Involvement:

Author

Publications (33)

Proceedings Article | 1 April 2020 Presentation + Paper

Relaxation oscillations suppression and undamping in a hybrid photonic crystal laser

Anton Kovalev, Sharon Butler, Andrei Bakoz, Stephen Hegarty, Liam O’Faolain, Evgeny Viktorov

Proceedings Volume 11356, 113560P (2020) https://doi.org/10.1117/12.2556531

KEYWORDS: Photonic crystals, Semiconductor lasers, Laser resonators, Silicon, Silicon photonics, Hybrid silicon lasers

Read Abstract +

As demand towards cloud-based services and high-performance computations grows, it imposes requirements on data center performance, and efficiency. Taking advantage of the mature CMOS process technology, and the fact that silicon is the basic material of electronics industry, silicon photonics makes possible production photonic integrated circuits that satisfy these requirements. Here we explore the short-cavity hybrid laser consisting of a III-V amplifier integrated with a silicon photonic crystal (PhC) cavity reflector by so-called butt-coupling approach. The laser possesses great stability characteristics meeting the criteria for data center interconnect applications. The PhC reflector having a Q-factor of 10⁴ at the lasing wavelength 1535 nm can be considered as a narrow-bandwidth filter. The laser demonstrates single mode and eventless operation without any dynamics on the background, and smooth radiofrequency spectrum without evidence of relaxation oscillation frequency. The latter fact is beneficial for many applications, and indicates extremely high damping in PhC laser, where the photon cavity lifetime is greatly improved by the high-Q PhC cavity reflector. We confirm our experimental observations by theory based on delay differential equation model for a single-section semiconductor laser. We reveal the effective damping of the laser, when the detuning between the filter peak and the laser cavity mode is small, and the imaginary parts of the model eigenvalues equal zero. It is possible to undamp the relaxation oscillations forcing self-Q-switched operation in the laser owing to the cumulative action of the alpha-factor and the narrow filter. In conclusion, we experimentally and theoretically demonstrated that relaxation oscillations can be suppressed in the short-cavity semiconductor laser with a narrow intracavity frequency filter. Additionally, on the basis of our analysis we expect the undamping of relaxation oscillations, and self-pulsations when the cavity mode is detuned from the filter peak frequency. The results might be useful for applications in data communications.

Proceedings Article | 4 March 2019 Presentation

Direct frequency modulation of photonic crystal laser by thermal tuning with low-intensity modulation (Conference Presentation)

Sharon Butler, Praveen K. Singaravelu, Andrei Bakoz, Alexandros Liles, Ben O'Shaughnessy, Evgeny Viktorov, Liam O'Faolain, Stephen Hegarty

Proceedings Volume 10923, 109230J (2019) https://doi.org/10.1117/12.2509729

KEYWORDS: Modulation, Photonic crystals, Frequency modulation, Laser crystals, Photonic integrated circuits, Resonators, Reflectivity, Silicon, Reflectors, Electro optics

Read Abstract +

Proceedings Article | 9 May 2018 Paper

Frequency modulated external cavity laser with photonic crystal resonator and microheater

Sharon Butler, Andrei Bakoz, Alexandros Liles, Evgeny Viktorov, Liam O'Faolain, Stephen Hegarty

Proceedings Volume 10682, 106822D (2018) https://doi.org/10.1117/12.2319142

KEYWORDS: Modulation, Laser resonators, Photonic crystals, Resonators, Frequency modulation, Silicon, Heterodyning, Semiconductor lasers

Read Abstract +

Proceedings Article | 22 February 2017 Paper

Excited state spectral blowup induced by carrier dynamics in the ground state of a quantum dot laser

Bryan Kelleher, David Goulding, Boguslaw Tykalewicz, Stephen Hegarty, Ilya Dubinkin, Nikita Federov, Thomas Erneux, Evgeny Viktorov

Proceedings Volume 10098, 1009818 (2017) https://doi.org/10.1117/12.2252476

KEYWORDS: Quantum dot lasers, Semiconductor lasers, Carrier dynamics, Laser optics, Bistability, Switching, Stereolithography, Tunable lasers, Picosecond phenomena, Quantum dots, Physics, Information technology

Read Abstract +

Proceedings Article | 20 February 2017 Presentation + Paper

Sub-wavelength gratings for mid-infrared wavlength range around 10 microns

Brian Hogan, Stephen Hegarty, Liam Lewis, Javier Romero Vivas, Tomasz Ochalski, Guillaume Huyet

Proceedings Volume 10113, 101130D (2017) https://doi.org/10.1117/12.2251937

KEYWORDS: Reflectors, Optical design, Electron beam lithography, Mirrors, Optical components, Optical filters, Polarizers, Telecommunications, Biological research, Biosensing, Reflectivity, Germanium, Refractive index, Etching, Optical lithography, Silicon, Lithography, Photoresist materials, Mid-IR

Read Abstract +

Proceedings Article | 28 April 2016 Paper

Lasing dynamics of photonic crystal reflector laser

Andrei Bakoz, A. Liles, E. Viktorov, L. O'Faolain, T. Habruseva, G. Huyet, S. Hegarty

Proceedings Volume 9892, 989204 (2016) https://doi.org/10.1117/12.2227560

KEYWORDS: Photonic crystals, Optical filters, Semiconductor lasers, Reflectors, Optical amplifiers, Reflectivity, Modulation, Waveguides, Frequency modulation, Reflection

Read Abstract +

Proceedings Article | 28 April 2016 Paper

Dual state antiphase excitability in optically injected quantum dot lasers

B. Kelleher, D. Goulding, B. Tykalewicz, N. Fedorov, I. Dubinkin, S. Hegarty, G. Huyet, T. Erneux, E. Viktorov

Proceedings Volume 9892, 98920V (2016) https://doi.org/10.1117/12.2227537

KEYWORDS: Laser optics, Semiconductor lasers, Quantum dot lasers, Switching, Mode locking, Quantum optics, Lasers, Ultrafast phenomena, Switches, Numerical simulations, Quantum dots, Stereolithography, Indium arsenide, Tunable lasers

Read Abstract +

Proceedings Article | 9 March 2016 Paper

Convective Nozaki-Bekki holes in a long cavity laser

Svetlana Slepneva, Ben O'Shaughnessy, Stephen Hegarty, Bryan Kelleher, Sergio Rica, Guillaume Huyet

Proceedings Volume 9732, 97320F (2016) https://doi.org/10.1117/12.2209403

KEYWORDS: Optical coherence tomography, Modulation, Tunable lasers, Mode locking, Semiconductor lasers, Light sources, Optical isolators, Laser applications, Optical semiconductors

Read Abstract +

Proceedings Article | 4 March 2016 Paper

Coherence properties of fast frequency swept lasers revealed via full electric field reconstruction

Thomas Butler, David Goulding, Svetlana Slepneva, Ben O’Shaughnessy, Bryan Kelleher, Stephen Hegarty, Hong Chou Lyu, Karol Karnowski, Maciej Wojtkowski, Andrei Vladimirov, Guillaume Huyet

Proceedings Volume 9742, 97420K (2016) https://doi.org/10.1117/12.2209615

KEYWORDS: Systems modeling, Optical coherence tomography, Mode locking, Interferometry, Semiconductor lasers, Optical filters, Electronic filtering, Tunable filters, Chaos, Laser applications, Phase measurement, Laser metrology, Terahertz radiation, Laser development, Laser optics

Read Abstract +

Proceedings Article | 4 March 2016 Paper

Lasing state hysteresis in a two-state quantum dot laser via optical injection

Bryan Kelleher, David Goulding, Bogsulaw Tykalewicz, Nikita Fedorov, Ilya Dubinkin, Stephen Hegarty, Guillaume Huyet, Thomas Erneux, Evgeny Viktorov

Proceedings Volume 9742, 97420D (2016) https://doi.org/10.1117/12.2212596

KEYWORDS: Quantum dot lasers, Laser optics, Bistability, Lasers, Semiconductor lasers, Indium arsenide, Pulsed laser operation, Systems modeling, Laser systems engineering, Physics, Stereolithography, Numerical simulations, Quantum dots

Read Abstract +

Proceedings Article | 16 March 2015 Paper

Optothermal excitabilities and instabilities in quantum dot lasers

Evgeny Viktorov, Thomas Erneux, Boguslaw Tykalewicz, David Goulding, Stephen Hegarty, Guillaume Huyet, Bryan Kelleher

Proceedings Volume 9357, 935704 (2015) https://doi.org/10.1117/12.2079843

KEYWORDS: Quantum dot lasers, Semiconductor lasers, Tunable lasers, Laser stabilization, Laser optics, Refractive index, Switches, Nonlinear optics, Optoelectronics, Neodymium

Read Abstract +

Proceedings Article | 16 March 2015 Paper

Phase and frequency dynamics of Fourier domain mode locked OCT lasers

B. Kelleher, David Goulding, Svetlana Slepneva, Ben O'Shaughnessy, T. Butler, S. Hegarty, A. Vladimirov, G. Huyet

Proceedings Volume 9357, 93570Z (2015) https://doi.org/10.1117/12.2079152

KEYWORDS: Mode locking, Optical coherence tomography, Oscilloscopes, Analytical research, Semiconductors, Numerical simulations, Zoom lenses, Tunable lasers, Optical semiconductors, Optical isolators

Read Abstract +

Proceedings Article | 16 March 2015 Paper

Ultrafast dynamic switching between two lasing states in quantum dot lasers

Boguslaw Tykalewicz, David Goulding, Stephen Hegarty, Guillaume Huyet, Evgeny Viktorov, Bryan Kelleher

Proceedings Volume 9357, 93570M (2015) https://doi.org/10.1117/12.2078973

KEYWORDS: Switching, Quantum dot lasers, Ultrafast phenomena, Stereolithography, Semiconductor lasers, Laser optics, Switches, Modulation, Quantum wells, Laser damage threshold

Read Abstract +

Proceedings Article | 2 March 2015 Paper

Phase evolution and instantaneous linewidth of a Fourier domain mode locked laser

S. Slepneva, B. O'Shaughnessy, T. Butler, B. Kelleher, D. Goulding, S. Hegarty, A. Vladimirov, G. Huyet

Proceedings Volume 9312, 93123A (2015) https://doi.org/10.1117/12.2078949

KEYWORDS: Optical coherence tomography, Laser applications, Mode locking, Analytical research, Laser optics, Numerical simulations, Coherence (optics), Optical isolators, Optical simulations, Optical semiconductors

Read Abstract +

Proceedings Article | 2 March 2015 Paper

Phase and frequency dynamics of a short cavity swept-source OCT laser

Thomas Butler, D. Goulding, S. Slepneva, B. O'Shaughnessy, B. Kelleher, H-C. Lyu, S. Hegarty, A. Vladimirov, K. Karnowski, M. Wojtkowski, G. Huyet

Proceedings Volume 9312, 93123C (2015) https://doi.org/10.1117/12.2077184

KEYWORDS: Optical coherence tomography, Mode locking, Tunable lasers, Interferometry, Chaos, Laser development, Analytical research, Modeling, Coherence (optics), Numerical simulations

Read Abstract +

Proceedings Article | 2 May 2014 Paper

Wider-frequency combs generation, noise reduction, and repetition rate tuning in quantum-dot mode-locked lasers

T. Habruseva, D. Arsenijević, D. Bimberg, Guillaume Huyet, S. Hegarty

Proceedings Volume 9134, 91340F (2014) https://doi.org/10.1117/12.2052351

KEYWORDS: Mode locking, Frequency combs, Modulation, Denoising, Hybrid optics, Semiconductor lasers, Laser optics, Optical filters, Laser applications, Picosecond phenomena

Read Abstract +

Proceedings Article | 2 May 2014 Paper

All-optical switching with a dual state quantum dot laser

Boguslaw Tykalewicz, David Goulding, Stephen Hegarty, Guillaume Huyet, Bryan Kelleher

Proceedings Volume 9134, 91341B (2014) https://doi.org/10.1117/12.2052360

KEYWORDS: Stereolithography, Switching, Quantum dot lasers, Semiconductor lasers, Analytical research, Laser optics, Lasers, Laser damage threshold, Polarization, Quantum dots

Read Abstract +

Proceedings Article | 2 May 2014 Paper

Time-resolved reconstruction of dynamical pulse trains using multiheterodyne detection

T. Butler, B. Tykalewicz, D. Goulding, B. Kelleher, Guillaume Huyet, S. Hegarty

Proceedings Volume 9134, 91341D (2014) https://doi.org/10.1117/12.2052386

KEYWORDS: Modulation, Phase measurement, Oscilloscopes, Phase shift keying, Modulators, Pulsed laser operation, Fermium, Frequency modulation, Frequency combs, Mode locking

Read Abstract +

Proceedings Article | 2 May 2014 Paper

Feedback-generated periodic pulse trains in quantum dot lasers

Evgeny Viktorov, David Goulding, Stephen Hegarty, Guillaume Huyet, Thomas Erneux, Bryan Kelleher

Proceedings Volume 9134, 91341F (2014) https://doi.org/10.1117/12.2052405

KEYWORDS: Quantum dot lasers, Semiconductor lasers, Mode locking, Laser optics, Quantum dots, Semiconductors, Pulsed laser operation, Attenuators, Feedback control, Information technology

Read Abstract +

Proceedings Article | 28 April 2010 Paper

40-GHz GaInNAs-based passively mode-locked laser diode

K. Haring, J. Thoma, T. Ochalski, S. Hegarty, J. Puustinen, J. Viheriälä, G. Huyet, M. Guina

Proceedings Volume 7720, 772017 (2010) https://doi.org/10.1117/12.854473

KEYWORDS: Gallium arsenide, Quantum wells, Mode locking, Semiconductor lasers, Picosecond phenomena, Silicon, Waveguides, Cladding, Luminescence, Etching

Read Abstract +

Proceedings Article | 28 April 2010 Paper

Quantum-dot mode-locked lasers with dual mode optical injection

Tatiana Habruseva, Natalia Rebrova, Stephen Hegarty, Guillaume Huyet

Proceedings Volume 7720, 77200Z (2010) https://doi.org/10.1117/12.854338

KEYWORDS: Mode locking, Laser optics, Modulators, Picosecond phenomena, Pulsed laser operation, Modes of laser operation, Tunable lasers, Heterodyning, Interference (communication), Laser applications

Read Abstract +

Proceedings Article | 27 April 2010 Paper

Numerical and experimental study of quantum dot mode-locked lasers with single mode optical injection

Natalia Rebrova, Tatiana Habruseva, Stephen Hegarty, Guillaume Huyet

Proceedings Volume 7720, 77200G (2010) https://doi.org/10.1117/12.854049

KEYWORDS: Picosecond phenomena, Mode locking, Quantum dots, Laser optics, Semiconductor lasers, Singular optics, Pulsed laser operation, Laser applications, Tunable lasers, Numerical simulations

Read Abstract +

Proceedings Article | 23 January 2010 Paper

Quantum-dot mode-locked lasers with optical injection

Tatiana Habruseva, Shane O'Donoghue, Natalia Rebrova, Stephen Hegarty, Guillaume Huyet

Proceedings Volume 7608, 760803 (2010) https://doi.org/10.1117/12.846854

KEYWORDS: Mode locking, Laser optics, Pulsed laser operation, Radio optics, Gallium arsenide, Modes of laser operation, Quantum optics, Semiconductor lasers, Quantum wells, Optical testing

Read Abstract +

Proceedings Article | 8 February 2007 Paper

Robust passively mode-locked quantum-dot lasers with low timing jitter

Maria Todaro, Jean-Philippe Tourrenc, Stephen Hegarty, Carmel Kelleher, Brian Corbett, Guillaume Huyet, John McInerney

Proceedings Volume 6485, 64850L (2007) https://doi.org/10.1117/12.714265

KEYWORDS: Mode locking, Picosecond phenomena, Tolerancing, Pulsed laser operation, Semiconductor lasers, Modulation, Control systems, Temperature metrology, Quantum dot lasers, Indium arsenide

Read Abstract +

Proceedings Article | 14 April 2006 Paper

Phase amplitude coupling of semiconductor lasers

David Goulding, Stephen Hegarty, Guillaume Huyet

Proceedings Volume 6184, 618416 (2006) https://doi.org/10.1117/12.662788

KEYWORDS: Semiconductor lasers, Refractive index, Tunable lasers, Absorption, Modulation, Laser damage threshold, Signal to noise ratio, Semiconductors, Chemical species, Semiconductor materials

Read Abstract +

Proceedings Article | 1 September 2004 Paper

Damping and feedback characteristics of quantum dot semiconductor lasers

Guillaume Huyet, Stephen Hegarty, David O'Brien, Alexander Uskov, S. Melnik, Olwen Carroll, John McInerney, Thorsten Kettler, Matthias Laemmlin, Dieter Bimberg, Victor Ustinov, Sergey Mikhrin, Alexey Zhukov, Alexey Kovsh

Proceedings Volume 5452, (2004) https://doi.org/10.1117/12.545457

KEYWORDS: Semiconductor lasers, Quantum dots, Laser optics, Quantum wells, Microwave radiation, Measurement devices, Laser stabilization, Calcium, Optical isolators, Quantum dot lasers

Read Abstract +

Proceedings Article | 1 September 2004 Paper

Bistable systems with noise and delay

David Curtin, Stephen Hegarty, David Goulding, John Houlihan, Thomas Busch, Cristina Masoller, Guillaume Huyet

Proceedings Volume 5452, (2004) https://doi.org/10.1117/12.545491

KEYWORDS: Vertical cavity surface emitting lasers, Polarization, Systems modeling, Switching, Switches, Stochastic processes, Polarizers, Signal to noise ratio, Optoelectronics, Bistability

Read Abstract +

Proceedings Article | 14 June 2004 Paper

Reduced sensitivity to external feedback in quantum dot lasers

Guillaume Huyet, David O'Brien, Stephen Hegarty, John McInerney, Dieter Bimberg, Christian Ribbat, V. Ustinov, S. Mikhrin, A. Kovsh, A. V. Uskov

Proceedings Volume 5361, (2004) https://doi.org/10.1117/12.533016

KEYWORDS: Semiconductor lasers, Quantum dots, Quantum wells, Laser optics, Quantum dot lasers, Microwave radiation, Measurement devices, Laser stabilization, Optical isolators, Waveguides

Read Abstract +

Proceedings Article | 25 May 2004 Paper

Distribution of residence times in bistable noisy systems with time-delayed feedback

John Houlihan, Guillaume Huyet, Thomas Busch, Stephan Hegarty, David Goulding, David Curtin, Cristina Masoller

Proceedings Volume 5471, (2004) https://doi.org/10.1117/12.547017

KEYWORDS: Switching, Polarization, Vertical cavity surface emitting lasers, Switches, Systems modeling, Stochastic processes, Polarizers, Signal to noise ratio, Particles, Optoelectronics

Read Abstract +

Proceedings Article | 11 May 2004 Paper

High-power ultra-fast single- and multi-mode quantum dot lasers with superior beam profile

Roman Sellin, Dieter Bimberg, Victor Ustinov, Nikolai Ledentsov, Ilia Kaiander, Matthias Kuntz, Matthias Lämmlin, Kay Tan, Claudio Marinelli, Mark Thompson, Adrian Wonfor, Richard Penty, Ian White, David O'Brien, Stephan Hegarty, Guillaume Huyet, John McInerney, J. Kenton White

Proceedings Volume 5365, (2004) https://doi.org/10.1117/12.528296

KEYWORDS: Quantum wells, Semiconductor lasers, Gallium arsenide, Mode locking, Waveguides, Gallium, Modulation, Laser damage threshold, Cladding, Diodes

Read Abstract +

Proceedings Article | 7 July 1998 Paper

High-frequency fluctuations in semiconductor lasers with optical feedback

Guillaume Huyet, Stephen Hegarty, John McInerney

Proceedings Volume 3283, (1998) https://doi.org/10.1117/12.316709

KEYWORDS: Semiconductor lasers, Laser damage threshold, Laser optics, Signal analyzers, Modes of laser operation, Statistical analysis, Transient nonlinear optics, Microwave radiation, Statistical modeling, Mirrors

Read Abstract +

Proceedings Article | 20 April 1998 Paper

Off-axis emission from native-oxide-confined VCSELs

Stephen Hegarty, Guillaume Huyet, John McInerney, Hong Hou, Kent Choquette

Proceedings Volume 3286, (1998) https://doi.org/10.1117/12.305460

KEYWORDS: Tin, Vertical cavity surface emitting lasers, Oxides, Near field, Quantum wells, Near field optics, Lithium, Laser applications, Laser resonators, Resonators

Read Abstract +

Proceedings Article | 6 June 1997 Paper

Polarization dynamics and intensity noise in VCSELs

Stephen Hegarty, Guillaume Huyet, John McInerney, Hua Li

Proceedings Volume 2994, (1997) https://doi.org/10.1117/12.275561

KEYWORDS: Polarization, Vertical cavity surface emitting lasers, Switching, Anisotropy, Magnetism, Radio optics, Photodiodes, Bistability, Quantum wells, Power supplies

Read Abstract +

Showing 5 of 33 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years