High-speed Arbitrary Waveform Generator Research Articles

A Photonics-Assisted Binary/Quaternary Phase-Coded Microwave Signal Generator Applicable to Digital I/O Interfaces.

A photonics-assisted binary/quaternary phase-coded microwave signal generator with fundamental/doubling reconfigurable carrier frequency applicable to digital I/O interfaces is proposed and has been verified by experiments. This scheme is based on a cascade modulation scheme, which is used to reconfigure fundamental/doubling carrier frequency and load the phase-coded signal, respectively. By controlling the radio frequency (RF) switch and the bias voltages of the modulator, the switching of the fundamental or doubling carrier frequency can be realized. When the amplitudes and sequence pattern of the two independent coding signals are set reasonably, binary or quaternary phase-coded signals can be realized. The sequence pattern of coding signals is applicable to digital I/O interfaces and can be directly generated through the IO interfaces of FPGA instead of an expensive high-speed arbitrary waveform generator (AWG) or other digital-to-analog conversion (DAC) systems. A proof-of-concept experiment is carried out, and the performance of the proposed system is evaluated from the aspects of phase recovery accuracy and pulse compression capability. In addition, the influence of residual carrier suppression and polarization crosstalk in non-ideal states on phase shifting based on polarization adjustment has also been analyzed.

Control and Readout Software for Superconducting Quantum Computing

Being important parts of the superconducting quantum computer, the high-speed arbitrary waveform generator (AWG), ultraprecision dc source, and high-speed digitizer are used to manipulate the qubit. The complexity of an experimental setup increases rapidly as the number of qubits grows. Cumbersome instrument management, distortion of signals, and inefficiency of data transmission are gradually highlighted and become the bottlenecks in scaling up the number of qubits. In addition, fault-tolerant quantum computing has real-time feedback requirements of qubit states. To deal with these challenges, we propose an instrument management software design in this paper. The software maps the resources of separate instruments to a unified virtual instrument, achieving the scalability of the instruments. The processing and correction of signals are deployed on a server, which automatically corrects the distortion of the signals. By designing a multi-threaded mechanism for the AWG and a custom-defined data-link protocol for the digitizer, the efficiency of the software meets the requirements of experiments. Cooperating with the AWG and digitizer, the software provides the real-time feedback capability using an instruction compiler. Thus, the software meets the requirements of superconducting quantum computing, as demonstrated through its application to a 12-bit quantum experiment.

Silicon-organic hybrid (SOH) modulators for intensity-modulation / direct-detection links with line rates of up to 120 Gbit/s.

High-speed interconnects in data-center and campus-area networks crucially rely on efficient and technically simple transmission techniques that use intensity modulation and direct detection (IM/DD) to bridge distances of up to a few kilometers. This requires electro-optic modulators that combine low operation voltages with large modulation bandwidth and that can be operated at high symbol rates using integrated drive circuits. Here we explore the potential of silicon-organic hybrid (SOH) Mach-Zehnder modulators (MZM) for generating high-speed IM/DD signals at line rates of up to 120 Gbit/s. Using a SiGe BiCMOS signal-conditioning chip, we demonstrate that intensity-modulated duobinary (IDB) signaling allows to efficiently use the electrical bandwidth, thereby enabling line rates of up to 100 Gbit/s at bit error ratios (BER) of 8.5 × 10-5. This is the highest data rate achieved so far using a silicon-based MZM in combination with a dedicated signal-conditioning integrated circuit (IC). We further show four-level pulse-amplitude modulation (PAM4) at lines rates of up to 120 Gbit/s (BER = 3.2 × 10-3) using a high-speed arbitrary-waveform generator and a 0.5 mm long MZM. This is the highest data rate hitherto achieved with a sub-millimeter MZM on the silicon photonic platform.

Arbitrary two-dimensional spectrally encoded pattern generation—a new strategy for high-speed patterned illumination imaging

Patterned illumination is now a proven technique in optical metrology and imaging, and is widely employed in both industrial and biological applications. However, existing techniques are unable to meet the pressing need for higher imaging rates. To address this challenge, we propose and demonstrate two-dimensional (2D) mechanical-scan-free arbitrary patterned illumination by 2D spectral encoding. The illumination pattern is flexibly generated at high speed by spectral shaping together with wavelength-to-2D space mapping. Performance optimization of this new patterned illumination scheme (e.g., pattern distortion and resolution) is generally an ill-defined problem involving multiple interrelated parameters. We demonstrate proof-of-principle experiments based on a multiobjective optimization routine using a genetic algorithm to validate our optimization model as well as to show the feasibility of patterned illumination by use of spectral interferometry. Adopting the wisdom of high-speed arbitrary waveform generation routinely practiced in telecommunications as well as ultrafast wavelength-sweep mechanisms, the proposed method could have an impact on advanced imaging modalities, particularly when speed is of a critical concern.

An arbitrary waveform generator based chirped pulse Fourier transform spectrometer operating from 260 to 295 GHz

The performance of a chirped-pulse Fourier transform millimeter-wave spectrometer operating from 260 to 295GHz is described. The spectrometer uses a high-speed arbitrary waveform generator (AWG) to create both a chirped excitation pulse and the single-frequency local oscillator (LO) used for the final down conversion detection stage. The mm-wave excitation source is an active multiplier chain (factor of 24 frequency multiplication) with power output of greater than 10mW across the 260–295GHz frequency range. The LO, produced by a separate active multiplier chain (factor of 12 frequency multiplication), drives a subharmonic mixer which downconverts the molecular emission to the microwave region for digitization on a 100GS/s digital oscilloscope. All frequency sources in the experiment are locked to a 10MHz Rb-disciplined oscillator providing direct frequency calibration for molecular transitions in the Fourier transform frequency-domain spectrum. Benchmark measurements are presented on ethyl cyanide and 1-butyne and are used to illustrate advantages and tradeoffs compared with direct absorption millimeter-wave spectroscopy.

An All-Optical Transformer From Differential NRZ Data to Ultra-Wideband Pulse Stream

We propose and experimentally demonstrate a compact and cost-effective scheme based on a fiber Sagnac structure to realize real time conversion from differential nonreturn-to-zero (NRZ) data to ultra-wideband (UWB) pulse stream. The proposed conversion system for the UWB signal generation consists of a single-wavelength laser, a phase modulator, several polarization controllers, and optical couplers. Due to the optical interference between the two phase-modulated light waves with slight phase difference in the Sagnac loop, two sharp optical pulses with opposite polarities are obtained. With proper time delay, a UWB monocycle pulse stream is generated from the original differential NRZ data. Our proposed method gives a reliable, easy, and low-cost transformer from differential NRZ signal to UWB pulse stream, and no high-speed arbitrary waveform generator (AWG) is required in this all-optical transformer.

Toward a High-Speed Arbitrary Waveform Generation by a Novel Photonic Processing Structure

A new photonics-based method for high-speed arbitrary waveform generation is presented. It is based on generating high-speed short optical pulse samples and a grating and delay structure for amplitude weighting and time delaying the optical samples. In order to increase the number of samples, a novel delay-attenuation-coupling processing method is presented for realizing high resolution in waveform generation. Results are given for sawtooth waveform generation with fast fall time of 10% of period and waveform linearity deviation of 1%, demonstrating the high resolution and wide-band capabilities of this technique.

Arbitrary waveform generator for turbulence experiments

We have built a computer-controlled high-speed arbitrary waveform generator which has a bandwidth of 50 MHz. High-speed arbitrary waveform generators have a wide variety of possible applications. We built our waveform generator in order to produce repetitive, synthesized ‘‘noise’’ which can have any kind of statistical properties we desire. We have found this device to be quite useful in studying nonlinear mode coupling effects which occur when a weak warm beam interacts with waves on a slow wave structure.