Microwave photonics is an interdisciplinary research between radiofrequency (RF) engineering and photo-electronics, as shown in Figure 1. An RF input singal is imposed in an optical signal simply by using an external elelcto-optic modulator. The signal is then all-optically processed through photonic devices and emitted through photo-reciever as RF output. Its main field of applications is very divrese, exloreing 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 freqeuncy-independent propagation loss in network liks, 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 generationof 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.