Microwave photonics is an interdisciplinary research between radio-frequency (RF) engineering and photo-electronics, as shown in Figure 1. An RF input signal is imposed in an optical signal simply by using an external electo-optic modulator. The signal is then all-optically processed through photonic devices and emitted through photo-receiver as RF output. Its main field of applications is very diverse, exploring over broadband wireless networks, radar/satellite communications, sensors and warfare systems and extensively studied over the last few years.
Major advantages of microwave photonics over pure RF engineering systems.
- Significantly reduced size, weight, low and frequency-independent propagation loss in network links, immunity to electromagnetic waves and high capacity for broadband signals.
- Wide range operation frequency over the entire microwave (tens of GHz) and millimeter waves (hundreds of GHz) and a ultra-large signal bandwidth with fast processing and low loss.
A variety of research topics has been theoretically and experimentally investigated in microwave photonics as followings.
- Photonic generation of microwaves and millimeter waves and its detection.
- All-optical processing and controlling of RF signals.
- Development of photonic analogue-to-digital convertor.
- Radio-over-fiber systems.
Research activity of our group has been focused on the development of dynamic photonic delay lines, based on two main techniques: Brillouin slow and fast light and dynamic Brillouin grating reflectors in optical fibers. In particular, wide-range tunable true time delay has been experimentally demonstrated simply by combining slow light and photonic phase-shifter based on stimulated Brillouin scattering in optical fibers, designated separate carrier tuning technique.
Capmany, J., & Novak, D. (2007). Microwave photonics combines two worlds. Nature photonics, 1(6), 319.
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Yao, J. (2009). Microwave photonics. Journal of Lightwave Technology, 27(3), 314-335.
- Morton, P. A., & Khurgin, J. B. (2009). Microwave photonic delay line with separate tuning of the optical carrier. IEEE Photonics Technology Letters, 21(22), 1686-1688.
Sancho, J., Chin, S., Sagues, M., Loayssa, A., Lloret, J., Gasulla, I., … & Capmany, J. (2010). Dynamic microwave photonic filter using separate carrier tuning based on stimulated Brillouin scattering in fibers. IEEE Photonics Technology Letters, 22(23), 1753-1755.
Chin, S., Thévenaz, L., Sancho, J., Sales, S., Capmany, J., Berger, P., … & Dolfi, D. (2010). Broadband true time delay for microwave signal processing, using slow light based on stimulated Brillouin scattering in optical fibers. Optics express, 18(21), 22599-22613.