Abstract
A high-birefringent (Hi-Bi) Sagnac loop interferometer for torsion measurement is demonstrated. The sensing head is formed by a section of standard single mode fiber spliced between the output ports of a Hi-Bi coupler at 3 dB. The sensing configuration is characterized in torsion, temperature and strain. The results obtained indicate the viability of a torsion sensor independent of the temperature and strain cross-sensitivity effects. Additionally, in the proposed configuration all measurements are performed without the need of a polarization controller, a device most often required in standard Sagnac loops applied for sensing.

Abstract
This paper reflects on review of smart sensor activities for biomedical applications. The rise of biotechnology has provided innovative development of new therapies and detection methods for life threatening diseases. As a worldwide research focus, there is especially a strong interest in the use of microsystems in health care, particularly as smart implantable devices. Recent years have seen an increasing activity of hip and knee replacement and other type of implants, which are some of the most frequently performed surgical procedures in the world. Loosening of hip prosthesis is the dominant issue for many patients who undergo a hip arthroplasty. Artificial joints are subject to chronic infections associated with bacterial biofilms, which only can be eradicated by the traumatic removal of the implant followed by sustained intravenous antibiotic therapy. This review focuses on the clinical experience using all kinds of smart implants like orthopedic implants instrumented with strain gauges, retina implant system using image sensors. Technical design improvements will enhance function, quality of life, and longevity of total knee arthroplasty and all other kind of implants. Application of biocompatible nanomaterials in implantable biosensors for continuous monitoring of metabolites is an area of sustained scientific and technological interests. Crown Copyright

Abstract
An interferometer based on a D-shape chaotic optical fiber for measurement of multiparameters was proposed. The sensing structure relied on a D-shape fiber section spliced in between two singlemode fibers and interrogated in transmission. The optical spectrum was composed by multiple interference loss peaks, which were sensitive to the refractive index, temperature and strain-maximum sensitivities of 95.2 nm/RIU, 10.5 pm/ and -3.51 pm/µe, respectively, could be achieved. © The Author(s) 2012.

Abstract
It is described a large-core air-clad photonic crystal fiber-based sensing structure using the outer cladding as a light guide, which is highly sensitive to refractive index. The sensing head is based on multimodal interference, and relies on a single mode/large-core air-clad photonic crystal fiber/single mode fiber configuration. Using this configuration and controlling the light to travel in a segment of the outer cladding multimode fiber, it was possible to implement a sensing head and the results were obtained independently from variations of temperature, strain and refractive index. (c) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:10091011, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26726

Abstract
This article analyzes experimentally the limitations observed in a 45 km Raman amplified 4 x 40 Gb/s transmission system operating under multiple pump and single high pump power configurations. A signal-to-noise ratio of 19.2 dB, an extinction ratio of 10.4 dB and a jitter of 1097 fs are achieved for moderate pump powers and higher order stimulated Brillouin scattering lines give rise to system degradation for pump power levels more than 0.5 W. (C) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:14031407, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26827

Abstract
The Bruggeman effective medium is used to study the transition to hyperbolic dispersion of visible light in thin-film metal-dielectric composite metamaterial of varying mixing proportion. This transition is experimentally demonstrated by the detection of the swap between the refracted birefringence components in fabricated composites of silver nanowires embedded in anodic aluminium oxide. Three refraction regimes are observed in a single composite using excitation radiation on both sides of the transition.