There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Microwave photonics, which brings together the worlds of radiofrequency engineering and optoelectronics, has attracted great interest from both the research community and the commercial sector over the past 30 years and is set to have a bright future. The technology makes it possible to have functions in microwave systems that are complex or even not directly possible in the radiofrequency domain and also creates new opportunities for telecommunication networks. Here we introduce the technology to the photonics community and summarize recent research and important applications.

Microwave photonics combines two worlds

Course Description This is an advanced course in which we explore the field of Statistical Optics. Topics covered include such subjects as the statistical properties of natural (thermal) and laser light, spatial and temporal coherence, effects of partial coherence on optical imaging instruments, effects on imaging due to randomly inhomogeneous media, and a statistical treatment of the detection of light. Development of this more comprehensive model of the behavior of light draws upon the use of tools traditionally available to the electrical engineer, such as linear system theory and the theory of stochastic processes.

http://ieeexplore.ieee.org/iel5/3/23094/01073023.pdf

Statistical optics

Broadband and low loss capability of photonics has led to an ever-increasing interest in its use for the generation, processing, control and distribution of microwave and millimeter-wave signals for applications such as broadband wireless access networks, sensor networks, radar, satellite communitarians, instrumentation and warfare systems. In this tutorial, techniques developed in the last few years in microwave photonics are reviewed with an emphasis on the systems architectures for photonic generation and processing of microwave signals, photonic true-time delay beamforming, radio-over-fiber systems, and photonic analog-to-digital conversion. Challenges in system implementation for practical applications and new areas of research in microwave photonics are also discussed.

Microwave Photonics

We describe recent progress in integrated microwave photonics in wideband signal processing applications with a focus on the key signal processing building blocks, the realization of monolithic integration, and cascaded photonic signal processing for analog radio frequency (RF) photonic links. New developments in integration-based microwave photonic techniques, that have high potentialities to be used in a variety of sensing applications for enhanced resolution and speed are also presented.

https://www.mdpi.com/2304-6732/4/4/46/pdf

Integrated Microwave Photonics for Wideband Signal Processing

A new photonic signal processor topology is presented, which achieves high-Q value microwave bandpass filtering. It significantly increases the Q by means of a small free spectral range passive filter, while still operating the active stage with a large gain margin. The filter response demonstrates very high resolution microwave signal filtering with a measured Q value of 983.

High-Q optical microwave filter

New photonic filter structures for interference mitigation of microwave signals are presented. These novel fibre-based filters have a parallel topology, and overcome the problem of synthesising both a narrow stopband and a very-wide and flat passband. Results for these filters showed a stopband 6-dB width of 10 MHz at a frequency of 1.5 GHz, with flat passband, and a shape factor for -40 dB interference rejection of 7.8, which is the lowest reported for a photonic filter.

Photonics-based interference mitigation filters

A new structure for storing a radio frequency (RF) signal utilising a fibre-optic delay line is presented. It is based on a frequency shifting recirculating delay line loop for the RF pulse storage, which prevents lasing and enables multiple recirculations and long storage time to be realised. The new photonic RF memory (PRFM) can realise a long reconfigurable storage time, wide instantaneous bandwidth and high dynamic range. Experimental demonstration of the frequency shifting loop based PRFM has been carried out for the first time, showing a long and reconfigurable storage time of more than 300 μs with high signal fidelity.

Photonic Radio Frequency Memory Using Frequency Shifting Recirculating Delay Line Structure

A new noise mitigation design strategy for spectrum sliced microwave photonic filters is presented. It is based on making the spectral slice bandwidths narrower than the modulation frequency and making the spacing between slices larger than the photodetector bandwidth. Advantages of this approach are that it is particularly simple, it does not require additional components, and it does not distort the signal. A detailed theoretical model of the relative intensity noise in spectrum sliced photonic signal processors is presented, including the effects of modulation, dispersion, and multislice stochastic sources. The phenomenon of modulation-induced noise translation in spectrum-sliced photonic signal processors is also reported for the first time. Results show that the new design strategy for noise mitigation can realize a significant increase in the SNR for a filter operating at 6.3 GHz

Robert A. Minasian

Papers

Integrated Microwave Photonics for Wideband Signal Processing

High-Q optical microwave filter

Photonics-based interference mitigation filters

Photonic Radio Frequency Memory Using Frequency Shifting Recirculating Delay Line Structure

Noise Mitigation in Spectrum Sliced Microwave Photonic Signal Processors