Abstract
A novel architecture for an optical phase modulator is presented and experimentally demonstrated. This approach relies on a commercially available integrated Mach-Zehnder interferometer structure with Semiconductor Optical Amplifiers (MZI-SOA) and it is based in cross-phase modulation effect (XPM). The feasibility of the proposed optical phase modulator is experimentally investigated using different scenarios of input power and bit rates.

Abstract
An all-optical clocked set-reset flip-flop is experimentally demonstrated. It is based on a hybrid-integrated S-R latch and two additional Mach-Zehnder interferometer structures with semiconductor optical amplifiers acting as AND logic gates. The switching behaviour of the synchronous S-R flip-flop was investigated and 18 dB extinction ratio performance was achieved.

Abstract
In this study, the authors present an innovative gain clamping method to mitigate Erbium-doped fibre amplifiers transients under bursty or packetised traffic. This method is based on a lasing technique by means of a continuous wave feedback signal reflected on a fibre Bragg grating. The clamping was assessed using on a range of re-injected powers from -30 to -5 dBm and able to fully mitigate the packet transients. The performance of the system at 2.5 and 10.0 Gb/s was appraised for different inter-packets times being observed in all cases an improvement in the Q factor. Additionally, a study that includes a characterisation of the transients (gain excursion and decaying time) with the inter-packet parameters and a comparison with theory was also presented.

Abstract
Database query languages on relations (for example SQL) make it possible to join two relations. This operation is very common in desktop/server database systems but unfortunately query processing systems in networked embedded computer systems currently do not support this operation; specifically, the query processing systems TAG, TinyDB, Cougar do not support this. We show how a prioritized medium access control (MAC) protocol can be used to efficiently execute the database operation join for networked embedded computer systems where all computer nodes are in a single broadcast domain. © 2010 IEEE.

Abstract
Skeletal muscle presents an internal fibrous structure. The existence of muscle fibers surrounded by interstitial fluid originates an internal step refractive index profile that causes light scattering. One way to minimize this effect inside a muscle is to perform an optical clearing treatment, using an adequate solution that presents a refractive index higher than the interstitial fluid. We have studied muscle spectral transmittance during sample immersion in propylene glycol. With the collection of transmittance spectra registered during a period of 20 minutes of immersion we could represent spectral transmittance evolution for several wavelengths and verify that the tissue samples have become more translucent. The optical clearing effect created in the tissue samples was characterized by an increase of 45% above the natural transmittance and the variations observed in tissue mass, pH and global refractive index. We also identified the initial mechanisms of agent diffusion into the tissue and consequent tissue dehydration from the spectral transmittance evolution. The histological analysis of variations caused in the internal structure of the tissues permitted to better explain the optical clearing effect created. Considering a mathematical model developed in previous studies, we could estimate the amount of agent that was inserted into the tissue samples.

Abstract
It is known that the fibrous structure of muscle causes light scattering. This phenomenon occurs due to the refractive index discontinuities located between muscle fibers and interstitial fluid. To study the possibility of reducing light scattering inside muscle, we consider its spectral transmittance evolution during an immersion treatment with an optical clearing solution containing ethanol, glycerol, and distilled water. Our methodology consists of registering spectral transmittance of muscle samples while immersed in that solution. With the spectral data collected, we represent the transmittance evolution for some wavelengths during the treatment applied. Additionally, we study the variations that the treatment has caused on the samples regarding tissue refractive index and mass. By analyzing microscopic photographs of tissue cross section, we can also verify changes in the internal arrangement of muscle fibers caused by the immersion treatment. Due to a mathematical model that we develop, we can explain the variations observed in the studied parameters and estimate the amount of optical clearing agent that has diffused into the tissue samples during the immersion treatment. At the end of the study, we observe and explain the improvement in tissue spectral transmittance, which is approximately 65% after 20 min. (C) 2010 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3486539]