MOCCA Publications

Francesco Rinaldo Talenti, Stefan Wabnitz, Inès Ghorbel, Sylvain Combrié, Luca Aimone-Giggio, and Alfredo De Rossi
“Fast dispersion tailoring of multimode photonic crystal resonators”

Authors introduce a numerical procedure which permits us to drastically accelerate the design of multimode photonic crystal resonators. Specifically, we demonstrate that the optical response of an important class of such nanoscale structures is reproduced accurately by a simple, one-dimensional model within the entire spectral range of interest. This model can describe a variety of tapered photonic crystal structures. Orders of magnitude faster to solve, our approach can be used to optimize certain properties of the nanoscale cavity. Here we consider the case of a nanobeam cavity, for which the confinement results from the modulation of its width. The profile of the width is optimized in order to flatten the resonator dispersion profile (so that all modes are equally spaced in frequency). This result is particularly relevant for miniaturizing parametric generators of nonclassical light, optical nanocombs, and mode-locked laser sources. Our method can be easily extended to complex geometries, described by multiple parameters.

The article can be read following this link
Journal link (no open access) link


Konstantinos Pantzas, Sylvain Combrié, Myriam Bailly, Raphaël Mandouze, Francesco Rinaldi Talenti, Abdelmounaim Harouri, Bruno Gérard, Grégoire Beaudoin, Luc Le Gratiet, Gilles Patriarche, Alfredo de Rossi, Yoan Léger, Isabelle Sagnes, Arnaud Grisard
“Continuous-Wave Second-Harmonic Generation in Orientation-Patterned Gallium Phosphide Waveguides at Telecom Wavelengths”
ACS Photonics, 2022, 9, 6, 2032–2039, published 13 May 2022

A new process to produce orientation-patterned gallium phosphide (OP-GaP) on GaAs with almost perfectly parallel domain boundaries is presented. Taking advantage of the chemical selectivity between phosphides and arsenides, OP-GaP is processed into suspended shallow-ridge waveguides. Efficient second-harmonic generation from telecom wavelengths is achieved in both Type-I and Type-II polarisation configurations. The highest observed conversion efficiency is 200% W–1 cm–2, with a bandwidth of 2.67 nm in a 1 mm-long waveguide. The variation of the conversion efficiency with wavelength closely follows a squared cardinal sine function, in excellent agreement with theory, confirming the good uniformity of the poling period over the entire length of the waveguide.

The article can be read following this link.

Open access link here.

Sergey Sergeyev, Stanislav Kolpakov, and Yury Loika
“Vector harmonic mode-locking by acoustic resonance”
Photonics Research, Volume 9, Issue 8, pp. 1432-1438 (2021);

For an Er-doped fiber laser, for the first time, to the best of our knowledge, authors demonstrate both experimentally and theoretically a novel mechanism of harmonic mode-locking based on the electrostriction effect leading to excitation of the torsional acoustic modes in the transverse section of the laser. The exited torsional acoustic modes modulate the fiber birefringence that results in synchronization of oscillations at the harmonic modes and the linewidth narrowing with the increased signal-to-noise ratio of 30 dB. By adjusting the in-cavity birefringence based on tuning the polarization controller, authors enable the selection of the harmonic mode to be stabilized..

The article can be read following this link


Misha Sumetsky and Victor Vassiliev
“Angstrom-precise fabrication of surface nanoscale axial photonics (SNAP) microresonators with a flame”
Laser Physics Letters, Volume 19, published 7 April 2022

Aston University team demonstrated the fabrication of surface nanoscale axial photonics bottle microresonators with angstrom precision using a flame. They observed strongly unscalable behavior of the whispering gallery mode cutoff wavelengths with different radial quantum numbers along the fibre length.

The article can be read following this link.

J. M. Chavez-Boggio, D. Bodenmüller, A. Baig, S. Ahmed, T. Hansson, F. Talenti, S. Wabnitz, D. Modotto
“Frequency comb generation in silicon nitride ring resonators with amplitude modulated pump”
Proc. SPIE 11672, Laser Resonators, Microresonators, and Beam Control XXIII, 1167206 (5 March 2021);

The article investigates frequency comb generation in silicon nitride ring resonators by using a pump subject to a weak amplitude modulation. It shows that a partial locking is obtained when the external modulation frequency differs from the resonator free-spectral-range by up to hundreds of MHz.

Keywords: Frequency comb, silicon nitride ring resonators, amplitude modulated pump, coherence.

The article can be read following this link


Gabriel Marty, Sylvain Combrié, Fabrice Raineri and Alfredo De Rossi
“Photonic crystal optical parametric oscillator”
Nature Photonics, 15, January 2021, pp. 53–58

Teams at Thales and C2N have developed a new miniaturized source of light called Photonic Crystal Optical Parametric Oscillator. An Optical Parametric Oscillator (OPO) is similar to a laser as it generates coherent light, namely photons having the same frequency, direction and polarization, except that here photons are emitted in pairs. These pairs are correlated, meaning that their perturbations (e.g. fluctuation of their frequency) are not independent. This property is exploited in many ways, in particular to decrease the noise in sensitive measurements (quantum sensing), to encode and encrypt information (quantum communication) and also to perform computing. More info.

The article can be read following this link.