Waveguide lasers operating at 1084nm in neodymium-diffused lithium niobate

We report the demonstration of waveguide lasers in lithium niobate into which the active element neodymium has been introduced by thermal diffusion. The waveguides were fabricated using conventional Ti indiffusion, and optical feedback was provided by the polished endfaces alone. The absorbed power threshold of one waveguide laser was estimated at 13±3 mW for pumping at 814 nm, and its slope efficiency in terms of total lasing output as a function of absorbed pump power was estimated to be 55±8%. Laser output powers in excess of 100 mW were observed

The photoluminescence of erbium-doped silicon monoxide

Films of silicon monoxide coevaporated with erbium are shown to produce strong room temperature photoluminescence peaked at 1535nm after annealing at 600°C. Decay measurements show a double exponential function with lifetimes of 0.41ms and 2.12ms, suggesting two distinct optically active erbium sites. Photoluminescence excitation spectroscopy between 700nm and 860nm reveals a monotonic increase in photoluminescence intensity towards shorter wavelengths. This result suggests that the transfer of energy from the pump source to the erbium ions is mainly via the recombination of electron-hole pairs (photocarriers) which are created by absorption within the SiO

Limit overturning moment chuck

Limited memory capacity is one of the major constraints in Delay Tolerant Wireless Sensor Networks. Efficient management of the memory is critical to the performance of the network. This paper proposes a novel buffer management algorithm, SmartGap, a Quality of Information (QoI) targeted buffer management algorithm. That is, in a wireless sensor network that continuously measures a parameter which changes over time, such as temperature, the value of a single packet is governed by an estimation of its contribution to the recreation of the original signal. Attractive features of SmartGap include a low computational complexity and a simplified reconstruction of the original signal. An analysis and simulations in which the performance of SmartGap is compared with the performance of several commonly used buffer management algorithms in wireless sensor networks are provided in the paper. The simulations suggest that SmartGap indeed provides significantly improved QoI compared the other evaluated algorithms.QC 20150605</p

Tunable coupled-cavity waveguide laser at room temperature in Nd-diffused Ti:LiNbO₃

We report on a Y-junction channel waveguide laser, operating at room temperature, in Nd-diffused Ti:LiNbO3. Pumping was performed with a cw Ti:Al2O3 laser operating at 816 nm. With feedback provided only by the polished end faces of the device, a cw lasing threshold of ~39-mW launched pump power was obtained, with a slope efficiency of ~35%. Using 95% reflectivity mirrors at the waveguide ends, we reduced the lasing threshold to ~4 mW, with a slope efficiency of ~2.6%. Tuning of the lasing signal over a range of 2.3 nm around a center wavelength of 1092.7 nm was demonstrated, with a monolithically integrated phase modulator

An Accelerator-Based Wireless Sensor Network Processor in 130 nm CMOS

Networks of ultra-low-power nodes capable of sensing, computation, and wireless communication have applications in medicine, science, industrial automation, and security. Reducing power consumption requires the development of system-on-chip implementations that must provide both energy efficiency and adequate performance to meet the demands of the long deployment lifetimes and bursts of computation that characterize wireless sensor network (WSN) applications. Therefore, this work argues that designers should evaluate the design in terms of average power for an entire workload, including active and idle periods, not just the metric of energy-per-instruction.Engineering and Applied Science

Beat length measurement in directional couplers by thermo-optic modulation

In integrated optical directional couplers formed by two parallel waveguides, we measure the difference Δβ = βeven - βodd between the propagation constants of the 'supermodes'. They are coupled locally by heating a fine spot on one of the guides. When the spot is scanned along the coupler the output power from one of the guides is found to vary periodically. The period of variation is the modal beat length λ = 2π/Δβ. We demonstrate this technique with directional couplers fabricated by K+-exchange in glass. Beat lengths in the range of 0.6 ... 2.2 mm are measured with an accuracy of ±0.3%.<br/

Neodymium-diffused tunable Y-branch waveguide laser in LiNbO₃ operating at room temperature

Rare-earth-doped waveguide optical lasers and amplifiers have received considerable attention in recent years, both in fibre form and as channel waveguides on planar substrates. Channel waveguide geometries lend themselves ideally for applications in active integrated circuits, with the potential for photolithographic definition of complex-cavity devices and monolithically integrated modulators for tuning, line-narrowing, Q-switching and mode-locking

Diagnosis of Cystic Fibrosis: Consensus Guidelines from the Cystic Fibrosis Foundation.

OBJECTIVE: Cystic fibrosis (CF), caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, continues to present diagnostic challenges. Newborn screening and an evolving understanding of CF genetics have prompted a reconsideration of the diagnosis criteria. STUDY DESIGN: To improve diagnosis and achieve standardized definitions worldwide, the CF Foundation convened a committee of 32 experts in CF diagnosis from 9 countries to develop clear and actionable consensus guidelines on the diagnosis of CF and to clarify diagnostic criteria and terminology for other disorders associated with CFTR mutations. An a priori threshold of ≥80% affirmative votes was required for acceptance of each recommendation statement. RESULTS: After reviewing relevant literature, the committee convened to review evidence and cases. Following the conference, consensus statements were developed by an executive subcommittee. The entire consensus committee voted and approved 27 of 28 statements, 7 of which needed revisions and a second round of voting. CONCLUSIONS: It is recommended that diagnoses associated with CFTR mutations in all individuals, from newborn to adult, be established by evaluation of CFTR function with a sweat chloride test. The latest mutation classifications annotated in the Clinical and Functional Translation of CFTR project (http://www.cftr2.org/index.php) should be used to aid in diagnosis. Newborns with a high immunoreactive trypsinogen level and inconclusive CFTR functional and genetic testing may be designated CFTR-related metabolic syndrome or CF screen positive, inconclusive diagnosis; these terms are now merged and equivalent, and CFTR-related metabolic syndrome/CF screen positive, inconclusive diagnosis may be used. International Statistical Classification of Diseases and Related Health Problems, 10th Revision codes for use in diagnoses associated with CFTR mutations are included