Serial Data Signals Research Articles

High-speed serial deep learning through temporal optical neurons.

Deep learning is able to functionally mimic the human brain and thus, it has attracted considerable recent interest. Optics-assisted deep learning is a promising approach to improve forward-propagation speed and reduce the power consumption of electronic-assisted techniques. However, present methods are based on a parallel processing approach that is inherently ineffective in dealing with the serial data signals at the core of information and communication technologies. Here, we propose and demonstrate a sequential optical deep learning concept that is specifically designed to directly process high-speed serial data. By utilizing ultra-short optical pulses as the information carriers, the neurons are distributed at different time slots in a serial pattern, and interconnected to each other through group delay dispersion. A 4-layer serial optical neural network (SONN) was constructed and trained for classification of both analog and digital signals with simulated accuracy rates of over 79.2% with proper individuality variance rates. Furthermore, we performed a proof-of-concept experiment of a pseudo-3-layer SONN to successfully recognize the ASCII codes of English letters at a data rate of 12 gigabits per second. This concept represents a novel one-dimensional realization of artificial neural networks, enabling a direct application of optical deep learning methods to the analysis and processing of serial data signals, while offering a new overall perspective for temporal signal processing.

Ultra‐Efficient and Broadband Nonlinear AlGaAs‐on‐Insulator Chip for Low‐Power Optical Signal Processing

AbstractFour‐wave mixing (FWM) is a versatile optical nonlinear parametric process that enables a plethora of signal processing functionalities in optical communication. Realization of efficient and broadband all‐optical signal processing with ultra‐low energy consumption has been elusive for decades. Although tremendous efforts have been put into developing various material platforms, it has remained a challenge to obtain both high efficiency and broadband operation. Here, an aluminum gallium arsenide nonlinear chip with high FWM conversion efficiency per length per pump power and an ultra‐broad bandwidth is presented. Combining an ultra‐high material nonlinearity and strong effective nonlinear enhancement from a high‐index‐contrast waveguide layout, an ultra‐high conversion efficiency of −4 dB is obtained in a 3‐mm‐long nano‐waveguide. Taking advantage of high‐order dispersion, a scheme is presented to realize an ultra‐broad continuous conversion bandwidth covering 1280–2020 nm. A microresonator is also utilized to demonstrate a conversion efficiency enhancement gain of more than 50 dB with respect to a waveguide device, which significantly reduces the power consumption. Moreover, wavelength conversion of an optical serial data signal is performed at a bit rate beyond terabit‐per‐second, showing the capabilities of this III‐V semiconductor material for broadband optical signal processing.

Crystal‐less oscillator calibration using serial data as frequency reference

A frequency calibration method for a crystal-less current-controlled ring oscillator is presented. It uses a serial data signal from another chip as the frequency reference. The proposed calibration circuit is composed of the coarse calibration and the fine calibration circuit. The coarse calibration circuit controls a binary weighted biasing current source array, while the fine calibration circuit generates a pulse-width-modulation (PWM) signal to control a switched biasing current source. The duty cycle ratio of the PWM signal is obtained by measuring the frequency ratio error between the oscillator output and the reference signal. An auto-correlation-based method is proposed to calculate the frequency ratio error. The 8 MHz ring oscillator in together with the calibration circuit has been fabricated in a 0.13 μm CMOS process. Measured results on 24 chips show that the relative frequency error is reduced to 0.0239% (mean offset + 3σ) after calibration. The reported oscillator shows advantages in accuracy, power consumption and chip area.

In brief

PAGE 995 The use of long coherent integration times in CZT-based algorithms could have applications for GPS systems operating in weak signal environments. A down-sampling data operation introduced by researchers in China demonstrates that the same signal acquisition can be achieved with a lower carrier-to-noise ratio and reduced computational effort. PAGE 991 Researchers in the UK working with semiconductor-based terahertz emitters have observed that temperature dependent polarity reversal within the material is an intrinsic property. Terahertz emission from various emitters over a range of temperatures revealed the semiconductor's inversion is not influenced by metallic contact, and creates potential for these devices to compete with commercial antennas. Signal detection probability improves with extended coherent integration times. PAGE 1007 A novel design for a simpler, more flexible, high performance microstrip power-divider (PD) has been implemented and tested by researchers in China. The device is composed of two dual-mode filtering PDs lacking any additional matching network, and provides significant design utility and size reduction with applications in wireless communications systems. Spectrometer set up for temperature dependence measurement of metal emitters. PAGE 967 Researchers from China have developed a frequency calibration method for a crystal-less current-controlled ring oscillator utilising a serial data signal from another chip as a reference. This newly presented auto-correlation method outperforms similar literature designs in terms of calibration accuracy, power consumption, and circuit area. Measured and simulated performances of power-divider device channels. PAGE 969 A purely digital approach to ultra-narrow pulse control for use in the picosecond and gigahertz domains has been presented by researchers in China. The digital synthesis method converts pulse-width control to the relative delay control between two signals, and can be applied to ultra-wideband communication systems and pulse radar. Frequency histograms before and after chip signal calibration. Diagram of ideal and real sharpener edge signal outputs.

Silicon Photonics for Signal Processing of Tbit/s Serial Data Signals

In this paper, we describe our recent work on signal processing of terabit per second optical serial data signals using pure silicon waveguides. We employ nonlinear optical signal processing in nanoengineered silicon waveguides to perform demultiplexing and optical waveform sampling of 1.28-Tbit/s data signals as well as wavelength conversion of up to 320-Gbit/s data signals. We demonstrate that the silicon waveguides are equally useful for amplitude and phase-modulated data signals.

A flexible FFT algorithm to process serial data signals using personal computer

AbstractThe aim of the paper is to demonstrate the possibility of using Personal Computer PC‐DOS (or generally MS‐DOS) for real time (or quasi real time) signal processing of serial data adding a simple A/D conversion card and the mathematical co‐processor XXX87.We have realized an assembly written FFT routine derived from a radix‐4 algorithm by Morris (1979). This algorithm is an autogenerated algorithm. This means that it is modified by another running off‐line algorithm according to the number of FFT points. The program is organized as subroutine to be called by high level language in different procedures.This approach reduces the computational time which is particularly useful when many Fourier transforms on different data array are required.Here reported are two biomedical applications of the routine for the spectral analysis of Doppler ultrasound velocimetry and for the surface electromiography (E.M.G.).