The past two decades have witnessed the stagnation of the clock speed of microprocessors followed by the recent faltering of Moore’s law as nanofabrication technology approaches its unavoidable physical limit. Vigorous efforts from various research areas have been made to develop power-efficient and ultrafast computing machines in this post-Moore’s law era. With its unique capacity to integrate complex electro-optic circuits on a single chip, integrated photonics has revolutionized the interconnects and has shown its striking potential in optical computing. Here, we propose an electronic-photonic computing architecture for a wavelength division multiplexing-based electronic-photonic arithmetic logic unit, which disentangles the exponential relationship between power and clock rate, leading to an enhancement in computation speed and power efficiency as compared to the state-of-the-art transistors-based circuits. We experimentally demonstrate its practicality by implementing a 4-bit arithmetic logic unit consisting of 8 high-speed microdisk modulators and operating at 20 GHz. This approach paves the way to future power-saving and high-speed electronic-photonic computing circuits.

A novel technique to perform dynamic strain measurement with a Brillouin optical time-domain reflectometry (BOTDR) sensing system based on short-time Fourier transform (STFT) is proposed. Unlike traditional frequency scanning methods, the proposed system samples the Brillouin backscattering signal directly after it has been downconverted to the intermediated frequency (IF) region. The Brillouin frequency shift (BFS) of the sensing fibre was reconstructed from the recorded time-domain data continuously without dead-time, which provided a much higher refreshing rate of the strain measurement. Therefore, dynamic strain variation over an optical fibre can be measured with a single-end structure that is more flexible and reliable. A 16.7 Hz strain variation on a 12 m section was successfully detected at the end of a 270 m sensing fibre with 4 m spatial resolution and 45 με uncertainty.Introduction: Distributed optical fibre sensors based on Brillouin scattering have attracted significant interest in the past few decades. By monitoring the Brillouin frequency shift (BFS) of the scattering signal generated by an injected probe pulse, the sensors can detect temperature and strain simultaneously [1, 2] along the entire length of a sensing fibre. Generally, there are two main kinds of technologies, namely, Brillouin optical time-domain reflectometry (BOTDR) and Brillouin optical timedomain analysis (BOTDA). Traditionally, both technologies require a time-consuming frequency scanning of the entire Brillouin gain spectrum (BGS) to obtain the BFS, which restricts the application of both technologies to static measurement only. Moreover, because of the weak spontaneous Brillouin backscattering signal, a great amount of average is needed even if coherent detection is introduced in the BOTDR sensing system [3]. For the BOTDA system, the signal is stronger because of the high stimulated Brillouin gain. Similar signal-to-noise ratio (SNR) can be achieved with much shorter integration time, that provide this technique with the potential for dynamic strain detection [4][5][6][7], especially when it works with the help of the slope-assisted technique. However, the requirement of having a two-end structure and the inability of straintemperature distinction [8] decrease its attraction and also limit its application realm.As a substitution for frequency scanning, Fourier transform was introduced to a BOTDR system. The BGS spectrum can be obtained without frequency scanning. In the literature [9], it takes 1 s to measure the temperature by using the Brillouin fibre laser and Fourier transform technique with 1024 data averages. Apparently, if one records the down-shifted backscattering power continuously with good SNR, the one-end measurement of the dynamic strain variation could be achieved.In this Letter, a dynamic strain-sensing BOTDR system based on short-time Fourier transform (STFT) is proposed and demonstrated. The BFS of the sensing fibre can be reconstructed from the recorded time-domain data continuously without dead-time, which...

We propose a plasmonic nano-optical conveyor belt for peristaltic transport of nano-particles. Instead of illumination from the top, waveguide-coupled excitation is used for trapping particles with a higher degree of precision and flexibility. Graded nano-rods with individual dimensions coded to have resonance at specific wavelengths are incorporated along the waveguide in order to produce spatially addressable hot spots. Consequently, by switching the excitation wavelength sequentially, particles can be transported to adjacent optical traps along the waveguide. The feasibility of this design is analyzed using three-dimensional finite-difference time-domain and Maxwell stress tensor methods. Simulation results show that this system is capable of exciting addressable traps and moving particles in a peristaltic fashion with tens of nanometers resolution. It is the first, to the best of our knowledge, report about a nano-optical conveyor belt with waveguide-coupled excitation, which is very important for scalability and on-chip integration. The proposed approach offers a new design direction for integrated waveguide-based optical manipulation devices and its application in large scale lab-on-a-chip integration.

Due to the projected saturation of Moore's law, as well as the drastically increasing trend of bandwidth with lower power consumption, silicon photonics has emerged as one of the most promising alternatives that has attracted a lasting interest due to the accessibility and maturity of ultra-compact passive and active integrated photonic components. In this Letter, we demonstrate a ripple-carry electro-optic 2-bit full adder using microdisks, which replaces the core part of an electrical full adder by optical counterparts and uses light to carry signals from one bit to the next with high bandwidth and low power consumption per bit. All control signals of the operands are applied simultaneously within each clock cycle. Thus, the severe latency issue that accumulates as the size of the full adder increases can be circumvented, allowing for an improvement in computing speed and a reduction in power consumption. This approach paves the way for future high-speed optical computing systems in the post-Moore's law era.

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