Rui Tang

Unitary optical processors (UOPs) are task-specific computing units that can ultimately enable ultrafast and energy-efficient unitary matrix-vector multiplications based on the interference between coherent optical beams. The UOP using multiport directional couplers (MDCs) holds great promise in large-scale integration because of its unique robustness against fabrication errors. Here, we demonstrate a 10-port robust UOP on a silicon photonic chip, which is so far the largest-scale UOP using mult

Reconfigurable unitary optical mode converters that can convert multiple orthogonal spatial modes into different orthogonal modes without fundamental optical loss are important for mode-division-multiplexed (MDM) optical communication, imaging, and quantum computation. In this letter, we propose a novel integrated reconfigurable unitary optical mode converter, which consists of cascaded multimode interference couplers and phase shifter arrays. We numerically investigate its ability to realize ar

We present, to the best of our knowledge, the first experimental demonstration of reconfigurable all-optical on-chip multi-input-multi-output three-mode demultiplexing based on multi-plane light conversion. The demultiplexer consists of cascaded phase shifter arrays and multimode interference couplers integrated on a compact silicon chip. By optimizing the phase shifters, reconfigurable three-mode demultiplexing is experimentally realized with wavelength-dependent loss of less than 3 dB and moda

We propose a narrow-spectral-linewidth silicon photonic wavelength-tunable laser with a novel external wavelength-tunable filter, which consists of two silicon ring resonators with different circumferences and a highly asymmetric Mach-Zehnder interferometer (MZI), the two optical paths of which have significantly different lengths. Calculations and experimental results indicated that the gain difference between longitudinal modes was increased by the highly asymmetric MZI. Consequently, a narrow

Photonic integrated circuits (PICs) are emerging as a promising tool for accelerating matrix multiplications in deep learning. Previous PIC architectures, primarily focusing on the matrix-vector multiplication (MVM), have large hardware errors that increase with the device scale. In this work, we propose a novel PIC architecture for MVM, which features an intrinsically small hardware error that does not increase with the device scale. Moreover, we further develop this concept and propose a PIC a

In order to design large digital circuits using quantum-dot cellular automata (QCA) cells, CAD tools and automated design methodology for QCA circuits are essential. This paper presents a QCA circuits design methodology based on traditional CMOS circuit design flow. This QCA circuit design methodology utilizes the current CMOS circuit design tools such as HSPICE and Synopsys design compiler. The QCA cell SPICE model is built for timing checking and accurate simulation. The basic QCA layout algor

This paper describes a SPICE model development methodology for Quantum-Dot Cellular Automata (QCA) cells and presents a SPICE model for QCA cells. The model is validated by simulating the basic logic gates such as inverter and majority voter. A full-adder is designed with QCA cells using the SPICE model as a test vehicle and the function is verified successfully. The proposed model makes it possible to design and simulate QCA combinational circuits and hybrid circuits of QCA and other NANO devic

Programmable linear optical processors (LOPs) can have widespread applications in computing and information processing due to their capabilities of implementing reconfigurable on-chip linear transformations. A conventional LOP that uses a mesh of Mach-Zehnder interferometers (MZIs) requires $2N+3$ stages of phase shifters for $N\ifmmode\times\else\texttimes\fi{}N$ matrices. However, it is beneficial to reduce the number of phase-shifter stages to realize a more compact and lower-loss LOP, especi

Photonic integrated circuits are emerging as a promising platform for accelerating matrix multiplications in deep learning, leveraging the inherent parallel nature of light. Although various schemes have been proposed and demonstrated to realize such photonic matrix accelerators, the in situ training of artificial neural networks using photonic accelerators remains challenging due to the difficulty of direct on-chip backpropagation on a photonic chip. In this work, we propose a silicon microring

We propose a novel reconfigurable integrated optical mode (de)multiplexer using cascaded multiport directional couplers and phase shifter arrays. Large fabrication tolerance and scalability up to 16-mode (de)multiplexing are demonstrated.

A novel phase-locked-loop (PLL) topology for pulse width modulation (PWM) technique in high speed I/O circuits is presented in this paper. The VCO of the PLL generates the eight phase clocks of the same frequency. A simple level shifter structure is used to amplify the VCO output signal to the full voltage swing and guarantee 50% duty cycle for a wide range of frequency. The performance of the charge-pump and phase- frequency detector is improved from the previous research. The proposed PLL can

This paper presents a jitter analysis method for PWM (pulse width modulation) scheme in high-speed serial links. The data rate of PWM with N different pulse widths (PWM-N) scheme is (log <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> N) times (symbol rate). However it increases the timing jitter of the transmitted signal. The timing jitter is determined by the pulse widths of PWM symbols and the characteristics of the communication channel.

Abstract. This paper presents a novel family of rigorous and flexible mathematical self-calibration additional parameters (APs) for airborne camera calibration. It is pointed out, that photogrammetric self-calibration can – to a very large extent – be considered as a function approximation problem in mathematics. Based on the mathematical approximation theory, we suggest that Fourier series (trigonometric polynomials) be the optimal mathematical basis functions for camera self-calibration. The w

Abstract Optical phase shifters are essential elements in photonic integrated circuits (PICs) and function as a direct interface to program the PICs. Non‐volatile phase shifters, which can retain information without a power supply, are highly desirable for low‐power static operations. Here a non‐volatile optical phase shifter is demonstrated by driving a III‐V/Si hybrid metal‐oxide‐semiconductor (MOS) phase shifter with a ferroelectric field‐effect transistor (FeFET) operating in the source foll