A Reconfigurable Surface-Plasmon-Based Filter/Sensor Using D-Shaped Photonic Crystal Fiber.

A reconfigurable surface-plasmon-based filter/sensor using D-shaped photonic crystal fiber is proposed. Initially a D-shaped PCF is designed and optimized to realize the highly birefringence and by ensuring the single polarization filter. A tiny layer of silver is placed on the flat surface of the D-shaped fiber with a small half-circular opening to activate the plasmon modes. By the surface plasmon effect a maximum confinement loss of about 713 dB/cm is realized at the operating wavelength of 1.98 µm in X-polarized mode. At this wavelength the proposed fiber only allows Y-polarization and filters the X-polarization using surface plasmon resonance. It is also exhibiting maximum confinement loss of about 426 dB/cm at wavelength 1.92 µm wavelength for Y-polarization. At this 1.92 µm wavelength the proposed structure attenuated the Y-polarization completely and allowed X-polarization alone. The proposed PCF polarization filter can be extended as a sensor by adding an analyte outside this filter structure. The proposed sensor can detect even a small refractive index (RI) variation of analytes ranging from 1.34-1.37. This sensor provides the maximum sensitivity of about 5000 nm/RIU; it enables this sensor to be ideally suited for various biosensing and industrial applications.

Quantum key based burst confidentiality in optical burst switched networks.

The optical burst switching (OBS) is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS). This paper deals with employing RC4 (stream cipher) to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks.

6-Fluoropyridoxal polymer conjugates: novel 19F pH indicators for magnetic resonance spectroscopy.

Fluorinated macromolecular probes (6-fluoropyridoxal-polymer conjugates) have been synthesized and characterized as potential pH indicators for magnetic resonance spectroscopy and imaging applications. The 19F pH sensor 2-fluoro-5-hydroxy-3-(hydroxymethyl)-6-methyl-4-pyridinecarboxal-+ ++dehyde (6-fluoropyridoxal; 2) has been conjugated to carrier molecules (polyamino dextran, polylysine, and albumin) by reductive alkylation for enhanced vascular retention and tissue targeting. The pH indicator polymer conjugates were purified by exhaustive dialysis and isolated in good yields (66-84%). The 6-fluoropyridoxal-polymer conjugates exhibit excellent 19F pH sensitivity and pKa suitable for in vivo studies. The potential application of these polymeric indicators has been demonstrated in whole blood. These novel macromolecular pH probes offer a new approach for studying tissue physiology.