Analog Coupled Oscillator Based Weighted Ising Machine.

We report on an analog computing system with coupled non-linear oscillators which is capable of solving complex combinatorial optimization problems using the weighted Ising model. The circuit is composed of a fully-connected 4-node LC oscillator network with low-cost electronic components and compatible with traditional integrated circuit technologies. We present the theoretical modeling, experimental characterization, and statistical analysis our system, demonstrating single-run ground state accuracies of 98% on randomized MAX-CUT problem sets with binary weights and 84% with 5-bit weight resolutions. Solutions are obtained within 5 oscillator cycles, and the time-to-solution has been demonstrated to scale directly with oscillator frequency. We present scaling analysis which suggests that large coupled oscillator networks may be used to solve computationally intensive problems faster and more efficiently than conventional algorithms. The proof-of-concept system presented here provides the foundation for realizing such larger scale systems using existing hardware technologies and could pave the way towards an entirely novel computing paradigm.

Monolithic integration of a nanomechanical resonator to an optical microdisk cavity.

We report a Silicon nano-opto-mechanical device in which a nanomechanical doubly-clamped beam resonator is integrated to an optical microdisk cavity. Small flexural oscillations of the beam cause intensity modulations in the circulating optical field in the nearby microdisk cavity. By monitoring the corresponding fluctuations in the cavity transmission via a fiber-taper, one can detect these oscillations with a displacement sensitivity approaching 10 fm·Hz-1/2 at an input power level of 50 µW. Both the in-plane and out-of-plane fundamental flexural resonances of the beam can be read out by this approach - the latter being detectable due to broken planar symmetry in the system. Access to multiple mechanical modes of the same resonator may be useful in some applications and may enable interesting fundamental studies.

Sensitive micromechanical displacement detection by scattering evanescent optical waves.

We describe a simple approach to detect small mechanical displacements by scattering evanescent optical waves confined around an optical waveguide. Our experimental setup consists of a microcantilever brought into the proximity of a tapered optical fiber. The scattering of evanescent waves and hence the optical transmission through the tapered fiber is strongly dependent on the separation between the fiber and the microcantilever, allowing for sensitive detection of the small oscillations of the microcantilever. Our approach does not require a coherent laser source, yet it provides a displacement sensitivity of ~260fmHz(-1/2) at a small power level of 38microW. It is suitable for scanning probe microscopy and could eventually be adapted to nanomechanical resonators.