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An analog photonic link with the compensation of the dispersion-induced power fading is proposed and demonstrated based on phase modulation to intensity modulation conversion in a Sagnac loop. Due to the velocity mismatch of the modulator, only the incident light wave along the clockwise direction is effectively modulated by the radio frequency signals, while the counterclockwise light wave is not modulated. After combining the two light waves in a polarizer, an intensity modulated optical signal is generated, which can be directly detected. In addition, the phase difference between the two light waves can be adjusted through the polarization controller before the polarizer. This feature is used to shift the frequency response of a dispersive link to compensate the dispersion-induced power fading at any working frequency. Experimental results show that the power fading after transmission over both 25 and 50 km lengths of fiber in a conventional intensity modulated link can be successfully compensated in the proposed link, and thus, a high and constant link gain over a large frequency range is achieved. The spur-free dynamic ranges of the link before and after fiber transmission are also measured.Index Terms-Analog photonic link (APL), chromatic dispersion, phase modulation to intensity modulation (PM-IM) conversion, power fading, radio over fiber (RoF), spur free dynamic range (SFDR). She is an author or coauthor of more than 50 research papers. Her research interests include chaotic optical communication, complex system and complex network, semiconductor lasers, and microwave photonics.Yong Wang received the B.E. degree in communication engineering in 1988 from Xidian University, Xi'an, China, and the M.S. degree in electrical circuit and system in 1991 from the Nanjing

Remediation of soil and groundwater contaminated with toxic metals has been a major environmental challenge for decades. Yet, cost-effective and sustainable in situ remediation technologies remain lacking. Over the last 15 years or so, an innovative in situ remediation strategy has shown promising by means of stabilized nanoparticles. Stabilized nanoparticles are prepared using novel stabilizers that facilitate the deliverability and transport of nanoparticles in the subsurface. This study reviews synthesis and characterization of some model stabilized nanoparticles and their application for remediation of metal-contaminated soil and water. Fate and transport of these stabilized nanoparticles in groundwater and soil are also examined. Lastly, this review identifies the key knowledge gaps such as lack of field data pertaining to the long-term effectiveness of the immobilized metals and impacts of the delivered nanoparticles on the biogeochemical conditions in the subsurface. The information may facilitate further development of this promising remediation technology.

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