2023 Vol. 6, No. 5

Cover story: Jiang SL, Chen FF, Zhao Y, Gao SF, Wang YY et al. Broadband all-fiber optical phase modulator based on photo-thermal effect in a gas-filled hollow-core fiber. Opto-Electron Adv 6, 220085 (2023).

All-optical modulation is an attractive but challenging topic in optical communication, sensing, laser, and signal processing. Recently, Professor Wei Jin and Dr. Shoulin Jiang in the Photonics Research Center at the Shenzhen Research Institute of the Hong Kong Polytechnic University reported a broadband all-fiber optical phase modulator based on the light-gas interaction in a hollow-core fiber (HCF). The proposed all-optical phase modulator is driven by a control light beam rather than an electrical signal, which is immune to electromagnetic interference. An insertion loss about 0.6 dB within C+L band and a half-wave power about 289 mW at 100 kHz is achieved, respectively. The gas-filled HCF-based all-optical modulator has a response time at μs scale, which is 2–3 orders better than the 2D-material-coated microfiber-based all-optical modulators. Due to the intrinsic limitation of the thermal conduction process, it is quite challenging to achieve modulation bandwidth over 1 MHz using this method. It may have promising applications in fiber optic interferometer-based phase demodulation systems in particular for harsh environments and remote applications, as well as for all-fiber actively Q-switched lasers, which do not require very high modulation bandwidth. The broad transmission bands of the state-of-the-art HCFs in combination with the many available gas species would also allow the development of all-optical modulators from ultraviolet to mid-infrared, which are quite challenging to realize with solid-state materials.

Back coverstory: Zhang H, Feng L, Wang FY, Liu MZ, Zhang YY et al. Janus aramid nanofiber aerogel incorporating plasmonic nanoparticles for highefficiency interfacial solar steam generation. Opto-Electron Adv 6, 220061 (2023).

Global demands for freshwater are steadily increasing to meet the growth of human population, development of industrial manufacture and expansion of agricultural irrigation. Traditional water production techniques, such as reverse osmosis and multi-stage flash, rely on costly infrastructures and high consumption of electric or fossil energy. Innovation of low-cost, energy-efficient and eco-friendly water desalination and purification devices has now been a key issue for future human lives. Interfacial solar steam generation (ISSG) is a novel and potential solution to global freshwater crisis. Here, Professor Ting Xu’s group from Nanjing University demonst- rates a highly scalable Janus aramid nanofiber aerogel (JANA) as a high-efficiency ISSG device based on the commercial Kevlar threads and Au nanoparticle. JANA performs near-perfect broadband optical absorption, rapid photothermal conversion and effective water transportation. Owning to these features, efficient desalination of salty water and purification of municipal sewage are successfully demonstrated using JANA. In addition, benefiting from the mechanical property and chemical stability of constituent aramid nanofibers, JANA not only possess outstanding flexibility and fire-resistance properties, but its solar steaming efficiency is also free from the influences of elastic deformations and fire treatments. JANA provides a promising platform for mass-production of high-efficiency ISSG devices with supplementary capabilities of convenient transportation and long-term storage, which could further promote the realistic applications of ISSG technology.


2024 Vol. 7, No. 3

ISSN (Print) 2096-4579
ISSN (Online) 2097-3993
CN 51-1781/TN
Prof. Xiangang Luo
Executive Editor-in-Chief: