[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Photonic signal processing offers the prospect of realizing extremely high multigigahertz sampling frequencies, overcoming inherent electronic limitations. This stems from the intrinsic excellent delay properties of optical delay lines. These processors provide new capabilities for realizing high time-bandwidth operation and high-resolution performance. In-fiber signal processors are inherently compatible with fiber-optic microwave systems and can provide connectivity with built-in signal conditioning. Fundamental principles of photonic signal processing, including sampling, tuning, and noise, are discussed. Structures that can extend the performance of photonic signal processors are presented, including methods for improving the filter shape characteristics of interference mitigation filters, techniques to increase the stopband attenuation of bandpass filters, and methods to achieve large free spectral range. Several photonic signal processors, including high-resolution microwave filters, widely tunable filters, arbitrary waveform generators, and fast signal correlators, are discussed. Techniques to solve the fundamental noise problem in photonic signal processors are described, and coherence-free structures for few-tap notch filters are discussed. Finally, a new concept for realizing multiple-tap coherence-free processor filters, based on a new frequency-shifting technique, is presented. The structure not only eliminates the phase-induced intensity noise limitation, but can also generate a large number of taps to enable the achievement of processors with high performance and high resolution.

Photonic signal processing of microwave signals

Micro-combs: A novel generation of optical sources

This paper reviews the recent advances in the field of radio frequency signal processing using photonic devices and subsystems or microwave photonic (MWP) signal processing. We focus our attention on the results reported during the last six years, as previous work has been adequately addressed in previous review papers. After a brief introduction to the basic concepts involved in MWP signal processing, we focus our attention on the most significant advances reported by different research groups in overcoming their main limitation factors. Recent advances in the emergent topic of integrated MWP signal processors are also covered and the novel approaches toward the evaluation of the main figures of merit are discussed. New proposed applications and future directions of work are also considered.

Microwave Photonic Signal Processing

This paper presents the fundamental principles and recent advances in the field of photonic filtering of microwave signals using discrete-time incoherent processing. We also provide a comprehensive review of the fundamentals, applications, and current state of the art.

Discrete-time optical Processing of microwave signals

Photonic signal processing offers the advantages of large time-bandwidth capabilities to overcome inherent electronic limitations. In-fibre signal processors are inherently compatible with fibre optic microwave systems that can integrate with wireless antennas, and can provide connectivity with in-built signal conditioning and electromagnetic interference immunity. Recent methods in wideband and adaptive signal processing, which address the challenge of realising programmable microwave photonic phase shifters and true-time delay elements for phased array beamforming; ultra-wideband Hilbert transformers; single passband, widely tunable, and switchable microwave photonic filters; and ultra-wideband microwave photonic mixers, are described. In addition, a new microwave photonic mixer structure is presented, which is based on using the inherent frequency selectivity of the stimulated Brillouin scattering loss spectrum to suppress the carrier of a dual-phase modulated optical signal. Results for the new microwave photonic mixer demonstrate an extremely wide bandwidth operation of 0.2 to 20 GHz and a large conversion efficiency improvement compared to the conventional microwave photonic mixer.

Microwave photonic signal processing.

Photonic signal processing offers a new powerful paradigm for processing high bandwidth signals, overcoming inherent electronic limitations. Recent new methods in wideband signal processors including high-resolution, arbitrary response, tunability and low noise processing, are presented.

A new optically controlled phased array beamforming technique based on phase modulations of wavelength-division-multiplexed (WDM) single sideband modulated light with carrier using a two-dimensional array liquid crystal on silicon (LCoS) pixels device, is presented. It realizes multiple wideband photonic microwave phase shifters, operates over a wide frequency range, and simultaneously integrates the array phase taper and the array amplitude taper within a single unit. The beamforming is software programmable. Experimental results demonstrate multiple independent microwave phase shifters that operate simultaneously over a 10- to 20-GHz frequency range, and results demonstrate beamsteering in a four-element optically controlled beam steering array at 18 GHz.

Photonic Beamforming Based on Programmable Phase Shifters With Amplitude and Phase Control

A new and simple structure for a single passband microwave photonic filter is presented. It is based on using an electro-optical phase modulator and a tunable optical filter and only requires a single wavelength source and a single photodetector. Experimental results are presented that demonstrate a single passband, flat-top radio-frequency filter response without free spectral range limitations, along with the capability of tuning the center frequency and filter bandwidth independently.

Single passband microwave photonic filter with wideband tunability and adjustable bandwidth

A new microwave photonic filter that solves the problem of realising a single bandpass RF response is presented. The filter is based on using phase modulation together with a pair of gratings, and eliminates the baseband response and periodic spectral response of typical FIR filters. Experimental results demonstrate a single passband square-type bandpass filter response, and operation to high frequencies.

Xiaoke Yi

Papers

Microwave photonic signal processing.

Photonic signal processing of microwave signals

Photonic Beamforming Based on Programmable Phase Shifters With Amplitude and Phase Control

Single passband microwave photonic filter with wideband tunability and adjustable bandwidth

Microwave photonic filter with single bandpass response