Ultra-High Temperature Gratings

Regenerated gratings seeded by type-I gratings are shown to withstand temperatures beyond 1000 ℃. The method of regeneration offers a new approach to increasing temperature resistance of stable fibre Bragg and other gratings. These ultra-high temperature （UHT） gratings extend the applicability of silicate based components to high temperature applications such as monitoring of smelters and vehicle and aircraft engines to high power fibre lasers.

Stable CW Single-Mode Photonic Crystal Fiber DFB Ring Laser

We demonstrate stable single-mode CW operation of a DFB ring laser based on Er3＋ doped photonics crystal fiber （PCF）. The incorporation of a ring cavity allows one single mode to lase and also suppresses the unwanted effect of self-pulsing. Such a narrow linewidth source in PCF has great potential in spectroscopy.

Structure formation dynamics in drawing silica photonic crystal fibres

The special features of photonic crystal fibres（PCFs）are achieved by their air hole structures.PCF structure is determined and formed by its origin preform design and drawing process.Therefore,structure formation dynamics in drawing PCF is important for the fabrication of PCF achieving desirable structure and thus the intended feature.This paper will investigate structure formation dynamics of PCF drawing in relation to key parameters and conditions,such as hole dimension,temperature,pressure,etc.

Additive Manufacturing Fiber Preforms for Structured Silica Fibers with Bismuth and Erbium Dopants

Dear Editor Silica optical fibers have attracted a lot of attention because they are widely used in communications and sensing,and forming today’s internet backbone.Driving much of the Internet-of-Things(IoT)evolution,optical fibers are expanding from a single function transmission technology to perform multiple functions and a growing need for various custom-design application-specific optical fibers.Current optical fiber manufacturing based on chemical vapor deposition(CVD)technologies together with stack-and-draw approaches used for structured optical fibers faces numerous challenges in enabling more complex geometries multimaterial composite fibers and multicore fibers.The additive manufacturing,or 3D printing,offers a solution to address all those challenges,and may potentially disrupt the optical fibers fabrication and bring in an evolution to IoT.

Optical Sensing： the Last Frontier for Enabling Intelligence in Our Wired up World and Beyond

Consigned to the shadows of telecommunications, optical sensing has often taken a back seat in a young person＇s mind when considering the importance of photonics, or optics, to the advancement of the society and of knowledge. Here, I touch on briefly how broad optical sensing and sensing generally has become and how and why it is becoming the catalyst for the convergence of many technologies and in the process raising significant philosophical questions about the transformation of our society and indeed ourselves. In doing so I touch on many of the complexities in real life that influence the breakthroughs we see today, including a healthy speculation and critique on our society and an awareness of the motivations to improve it that drive many of them.

Room Temperature Sol-Gel Fabrication and Functionalization for Sensor Applications

The structure and physical properties of a thin titania sol-gel layer prepared on silicon and silica surfaces were examined. Spectroscopic （FTIR, UV-VIS spectroscopy）, refractive index （ellipsometry） and microscopic （light microscopy and SEM/EDS） tools were used to examine both chemical uniformity and physical uniformity of the sol-gel glass layers. The conditions for the fabrication of uniform layers were established, and room temperature dopant incorporation was examined. The absorption bands of porphyrin-containing titania sol-gel layers were characterized. By addition of a metal salt to the titania layer, it was possible to metallate the free-base porphyrin within and change the UV-VIS absorbance of the porphyrin, the basis of metal detection using porphyrins. The metalloporphyrins were detected by localized laser ablation inductive coupled mass spectroscopy （LA-ICP-MS）, indicating fairly uniform distribution of metals across the titania surface.

Early Warning Smartphone Diagnostics for Water Security and Analysis Using Real-Time pH Mapping

Early detection of environmental disruption, unintentional or otherwise, is increasingly desired to ensure hazard minimization in many settings. Here, using a field-portable, smartphone fluorimeter to assess water quality based on the pH response of a designer probe, a map of pH of public tap water sites has been obtained. A custom designed Android application digitally processed and mapped the results utilizing the global positioning system （GPS） service of the smartphone. The map generated indicates no disruption in pH for all sites measured, and all the data are assessed to fall inside the upper limit of local government regulations, consistent with authority reported measurements. This implementation demonstrates a new security concept： network environmental forensics utilizing the potential of novel smartgrid analysis with wireless sensors for the detection of potential disruption to water quality at any point in the city. This concept is applicable across all smartgrid strategies within the next generation of the Internet of Things and can be extended on national and global scales to address a range of target analytes, both chemical and biological.

Grating Writing in Structured Optical Fibers

Grating writing in structured optical fibers is reviewed. Various laser sources have been used including UV and near IR nanosecond and femtosecond lasers, each enabling different material processing regimes. The issue of scattering is modeled through simulation and compared with experiment. Good agreement has been established.

Advances and New Applications Using the Acousto-Optic Effect in Optical Fibers

This work presents a short review of the current research on the acousto-optic mechanism applied to optical fibers. The role of the piezoelectric element and the acousto-optic modulator in the excitation of flexural and longitudinal acoustic modes in the frequency range up to 1.2 MHz is highlighted. A combination of the finite elements and the transfer matrix methods is used to simulate the interaction of the waves with Bragg and long period gratings. Results show a very good agreement with experimental data. Recent applications such as the writing of gratings under the acoustic excitation and a novel viscometer sensor based on the acousto-optic mechanism are discussed.