Injection locking in an optomechanical coherent phonon source

Abstract

Spontaneous locking of the phase of a coherent phonon source to an external reference is demonstrated in a deeply sideband-unresolved optomechanical system. The high-amplitude mechanical oscillations are driven by the anharmonic modulation of the radiation pressure force that result from an absorption-mediated free-carrier/temperature limit cycle, i.e., self-pulsing. Synchronization is observed when the pump laser driving the mechanical oscillator to a self-sustained state is modulated by a radiofrequency tone. We employ a pump-probe phonon detection scheme based on an independent optical cavity to observe only the mechanical oscillator dynamics. The lock range of the oscillation frequency, i.e., the Arnold tongue, is experimentally determined over a range of external reference strengths, evidencing the possibility to tune the oscillator frequency for a range up to 350 kHz. The stability of the coherent phonon source is evaluated via its phase noise, with a maximum achieved suppression of 44 dBc/Hz at 1 kHz offset for a 100 MHz mechanical resonator. Introducing a weak modulation in the excitation laser reveals as a further knob to trigger, control and stabilize the dynamical solutions of self-pulsing based optomechanical oscillators, thus enhancing their potential as acoustic wave sources in a single-layer silicon platform.

Thermal Properties of Nanocrystalline Silicon Nanobeams

“…Since the heat dissipation rate  obtained by µ-TDTR is not strictly equivalent to the thermal decay rate th in optomechanical devices due to the added contribution of the suspended central section and gold pad and their heat capacity. The nanobeams studied here have been extensively used as a platform for OM experiments, including self-pulsing 6,8 , chaotic behaviour 7 , injection locking 42 and synchronisation 43 , among others 23,27 . In this context, nonlinear dynamics involving self-pulsing limit cycle has played a key role.…”

“…The nanobeams studied here have been extensively used as a platform for OM experiments, including self-pulsing, [6,8] chaotic behavior, [7] injection locking, [42] and synchronization, [43] among others. [23,27] In this context, non-linear dynamics involving self-pulsing limit cycle have played a key role.…”

“…All measurements are performed in an anti‐vibration cage at ambient temperature and atmospheric air pressure. More details of the measurement system to characterize OM cavities are given in previous work [ 42 ] and a schematic of the setup is shown in Supporting Information.…”

Nanophotonic Reservoir Computing for COVID-19 Pandemic Forecasting

“…At present, vast amounts of photonic reservoir computing are concentrated on time-delayed RC architecture with semiconductor lasers (SLs) [20,23,[27][28][29][30], such as quantum dot laser [23], Fabry-Perot laser [20], and two-element phased laser array [27]. Intriguingly, with the progress of nanophotonic technology, it is particularly compelling that nanophotonic devices have incomparable advantages over semiconductor lasers in terms of scalability, com-plementary metal oxide semiconductor (CMOS) compatibility, monolithic integration and mass production [22,[31][32][33]. Thereby, the nanophotonic devices are promising candidates to consider for the COVID-19 forecast of high-efficiency nanophotonic reservoir computing.…”

Optomechanical Synchronization across Multi-Octaves Frequency Spans

“…Since its observation by Huygens in the 17 th century, the synchronization of widely distinct systems have been shown to share remarkably universal features [1,2], fostering its exploration across many disciplines [3][4][5]. With the recent convergence among optical, mechanical and electrical waves using scalable microfabrication technologies, synchronization has emerged as a powerful tool targeted not only at technological applications, such as phaselock loops (PLLs) in radio-based communications [6][7][8], but also at developing the fundamentals of chaotic systems [9], injection locking [10][11][12], electro and optomechanical devices [13][14][15][16][17][18][19][20], nonlinear dynamics [21][22][23][24][25], network coupling [26][27][28][29], and quantum synchronization [30][31][32][33][34][35].…”