Injection Locking of a Trapped-Ion Phonon Laser

We report on injection locking of optically excited mechanical oscillations of a single, trapped ion. The injection locking dynamics are studied by analyzing the oscillator spectrum with a spatially selective Fourier transform technique and the oscillator phase with stroboscopic imaging. In both cases we find excellent agreement with theory inside and outside the locking range. We attain injection locking with forces as low as 5(1)×10^(-24)  N so this system appears promising for the detection of ultraweak oscillating forces

Injection locking of optomechanical oscillators via acoustic waves

Injection locking is a powerful technique for synchronization of oscillator networks and controlling the phase and frequency of individual oscillators using similar or other types of oscillators. Here, we present the first demonstration of injection locking of a radiation-pressure driven optomechanical oscillator (OMO) via acoustic waves. As opposed to previously reported techniques (based on pump modulation or direct application of a modulated electrostatic force), injection locking of OMO via acoustic waves does not require optical power modulation or physical contact with the OMO and it can easily be implemented on various platforms. Using this approach we have locked the phase and frequency of two distinct modes of a microtoroidal silica OMO to a piezoelectric transducer (PZT). We have characterized the behavior of the injection locked OMO with three acoustic excitation configurations and showed that even without proper acoustic impedance matching the OMO can be locked to the PZT and tuned over 17 kHz with only -30 dBm of RF power fed to the PZT. The high efficiency, simplicity and scalability of the proposed approach paves the road toward a new class of photonic systems that rely on synchronization of several OMOs to a single or multiple RF oscillators with applications in optical communication, metrology and sensing. Beyond its practical applications, injection locking via acoustic waves can be used in fundamental studies in quantum optomechanics where thermal and optical isolation of the OMO are critical

Narrow line width frequency comb source based on an injection-locked III–V-on-silicon mode-locked laser

In this paper, we report the optical injection locking of an L-band (similar to 1580 nm) 4.7 GHz III-V-on-silicon mode-locked laser with a narrow line width continuous wave (CW) source. This technique allows us to reduce the MHz optical line width of the mode-locked laser longitudinal modes down to the line width of the source used for injection locking, 50 kHz. We show that more than 50 laser lines generated by the mode-locked laser are coherent with the narrow line width CW source. Two locking techniques are explored. In a first approach a hybrid mode-locked laser is injection-locked with a CW source. In a second approach, light from a modulated CW source is injected in a passively mode-locked laser cavity. The realization of such a frequency comb on a chip enables transceivers for high spectral efficiency optical communication. (C) 2016 Optical Society of Americ

Super-harmonic injection locking of nano-contact spin-torque vortex oscillators

Super-harmonic injection locking of single nano-contact (NC) spin-torque vortex oscillators (STVOs) subject to a small microwave current has been explored. Frequency locking was observed up to the fourth harmonic of the STVO fundamental frequency $f_{0}$ in microwave magneto-electronic measurements. The large frequency tunability of the STVO with respect to $f_{0}$ allowed the device to be locked to multiple sub-harmonics of the microwave frequency $f_{RF}$, or to the same sub-harmonic over a wide range of $f_{RF}$ by tuning the DC current. In general, analysis of the locking range, linewidth, and amplitude showed that the locking efficiency decreased as the harmonic number increased, as expected for harmonic synchronization of a non-linear oscillator. Time-resolved scanning Kerr microscopy (TRSKM) revealed significant differences in the spatial character of the magnetization dynamics of states locked to the fundamental and harmonic frequencies, suggesting significant differences in the core trajectories within the same device. Super-harmonic injection locking of a NC-STVO may open up possibilities for devices such as nanoscale frequency dividers, while differences in the core trajectory may allow mutual synchronisation to be achieved in multi-oscillator networks by tuning the spatial character of the dynamics within shared magnetic layers.Comment: 21 pages, 8 figure

Preliminary results toward injection locking of an incoherent laser array

The preliminary results of phase locking an incoherent laser array to a master source in an attempt to achieve coherent operation are presented. The techniques necessary to demonstrate phase locking are described along with some topics for future consideration. As expected, the results obtained suggest that injection locking of an array, where the spacing between adjacent longitudinal modes of its elements is significantly larger than the locking bandwidth, may not be feasible

Long wavelength VCSEL-by-VCSEL optical injection-Locking

VCSEL-by-VCSEL optical injection-locking to obtain high cut-off frequencies of 1.3 μm Vertical-Cavity Surface-Emitting Lasers (VCSELs) is demonstrated. A detailed physical explanation of the underlying mechanism is presented. VCSELs from the same wafer have been used in a master-follower configuration. Two probe stations are used in this experiment to power-up two VCSELs simultaneously. Polarization insensibility of the injection-locking is demonstrated and a novel architecture is proposed to achieve cut-off frequency doubling. For the first time a high cut-off frequency is achieved through optically injection-locking the satellite mode of a long wavelength VCSEL. Injection-locking spectra with variable injection-powers and variable detuning values have been obtained and methods have been proposed to obtain high cut-off and/or resonance frequencies. A rate-equation based model is presented. Simulations have been carried out using this model. Finally, a linear increases in the follower VCSEL cut-off frequency with increasing injected-power is demonstrated by using a semiconductor optical amplifier

Spin-transfer-torque resonant switching and injection locking in presence of a weak external microwave field for spin valves with perpendicular materials

The effects of a weak microwave field in the magnetization dynamics driven by spin-transfer-torque in spin-valves with perpendicular materials have been systematically studied by means of full micromagnetic simulations. In the system we studied, depending on the working point (bias field and current) in the dynamical stability diagram, we observe either resonant switching and injection locking. The resonant switching, observed in the switching region, occurs when the field frequency is approaching the frequency of the main pre-switching mode giving rise to an asymmetric power distribution of that mode in the sectional area of the free layer. At the resonant frequency, the switching time is weakly dependent on the relative phase between the instant when the current pulse is applied and the microwave field. The injection locking, observed in the dynamical region, is characterized by the following properties: (i) a locking bandwidth which is linearly dependent on the force locking, and (ii) a locking for integer harmonics of the self-oscillation frequency. We compare our numerical results with analytical theory for non-autonomous non-linear system obtaining a good agreement in the current region where the oscillation frequency and output power are characterized from a linear relationship

Frequency comb injection locking of mode locked lasers

The two-frequency problem of synchronization of the pulse train of a passively mode locked soliton laser to an externally injected pulse train is solved in the weak injection regime. The source and target frequency combs are distinguished by the spacing and offset frequency mismatches. Locking diagrams map the domain in the mismatch parameter space where stable locking of the combs is possible. We analyze the dependence of the locking behavior on the relative frequency and chirp of the source and target pulses, and the conditions where the relative offset frequency has to be actively stabilized. Locked steady states are characterized by a fixed source-target time and phase shifts that map the locking domain.Comment: 7 pages, 2 figure