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We introduce and provide experimental verification for a new model and representation of pump absorption in rare-earth-doped double-clad fibers based on underlying physics. The model allows for simple evaluation of wavelength resolved, length dependent absorption.

Improved nonlinear fiber designs have recently demonstrated intrinsically stable phase-matching. They remove dispersion variation limits, enabling efficient devices, for example a low-threshold oscillator tunable across wavelengths from 1.7-2.1 microns.

Simulations show that resonant shunt cores for suppression of higher-order modes in hollow-core fibers can be applied broadly, to cores larger than 19-cell and core thicknesses larger than half the lattice web thickness.

We present a single-mode hollow-core fiber with loss of 5.7 dB/km for low latency transmission. We demonstrated penalty-free transmission over 1 and 300 m at 10 Gb/s and 120 Gb/s without optimization of launch conditions.

We introduce a 3-parameter model to accurately capture the recently proposed, physically based, distribution function representation of pump absorption in rare-earth-doped double-clad fibers. This model allows for simple evaluation of wavelength resolved, length dependent absorption.

Long-term stable, sub-femtosecond timing distribution over a 1.2-km polarization-maintaining (PM) fiber-optic link using balanced optical cross-correlators for link stabilization is demonstrated. Novel dispersion-compensating PM fiber was developed to construct a dispersion-slope-compensated PM link, which eliminated slow timing drifts and jumps previously induced by polarization mode dispersion in standard single-mode fiber. Numerical simulations of nonlinear pulse propagation in the fiber link confirmed potential sub-100-as timing stability for pulse energies below 70 pJ. Link operation for 16 days showed ~0.6 fs RMS timing drift and during a 3-day interval only ~0.13 fs drift, which corresponds to a stability level of 10(-21).

Fibers with symmetric bend compensated claddings are proposed, and demonstrate performance much better than conventional designs. These fibers can simultaneously achieve complete HOM suppression, negligible bend loss, and mode area >1000 square microns. The robust single-modedness of these fibers offers a path to overcoming mode instability limits on high-power amplifiers and lasers. The proposed designs achieve many of the advantages of our previous (asymmetric) bend compensation strategy in the regime of moderately large area, and are much easier to fabricate and utilize.

We present here key technologies for an all-optical timing distribution system with sub-femtosecond precision. Timing distribution over a 1.2-km polarization-maintaining, fiber-optic link using balanced optical cross-correlators (BOC) for link stabilization was demonstrated for 16 days with 0.6 fs RMS timing drift and during a 3-day interval only 0.13 fs drift. Jitter characterization of two identical commercial femtosecond lasers using the BOC method verified sub-100-as timing jitter for frequencies above than 1 kHz. Preliminary operation of a fiber-coupled, hybrid-integrated BOC using periodically-poled KTiOPO4 (PPKTP) waveguides indicate great potential for improved BOC timing sensitivities and overall system efficiency and robustness.

The paper presents monolithic fiber-optic CPA systems - where the mode-locked oscillator, pulse stretcher, pulse shaper, pulse picker, and all amplifier stages are comprised of fusion spliced fiber devices - emitting up to 300 μJ compressed pulse output with duration

Improvements to a ground-based 40W 1.55 micron uplink transmitter for the Lunar Laser Communications Demonstration (LLCD) are described. The transmitter utilizes four 10 W spatial-diversity channels to broadcast 19.4 - 38.9 Mbit/s rates using a variable-duty cycle 4-ary pulse position modulation. At the lowest rate, with a 32-to-1 duty cycle, this leads to 320 W peak power per transmitter channel. This paper discusses a simplification of the transmitter that uses super-large-area single mode fiber and polarization control to mitigate high peak power nonlinear impairments.

Cellular proliferation in the prostatic ducts and acini presents a morphological continuum from benign proliferation without cytological atypia (hyperplasia) to proliferations with different degrees of dysplasia. The term prostatic intraepithelial neoplasm (P.I.N.) indicates the theoretical morphological extremity of that continuum. The criteria for differentiating P.I.N. into three grades are to be found in the cytological and architectural aspect as well as the integrity of the basal cell layer and the basal membrane. Clinically P.I.N. is strongly associated with prostatic carcinoma and diagnosis should be followed by further investigations for a co-existing carcinoma. All the elements (age, severity of P.I.N., P.S.A., D.R.E. and T.R.U.S. characteristics) which may be used for correct follow-up are discussed, as well as possible therapeutic options.

From 1987 to 1992, over 6,000 men aged between 50 and 79 years underwent mass screening for early diagnosis of prostatic carcinoma. They were also given an “epidemiological” questionnaire drawn up by a Urologist, which included information regarding civil status, fertility, working conditions, eating and smoking habits as well as tumours in the family. With regard to the latter, it appeared that 11% of patients with cancer have a positive family history against 2.2% in healthy men and 1.8% in individuals with benign prostatic hypertrophy. In order to investigate this aspect, 46 next of kin (brothers, sons) of patients with prostatic carcinoma (mean age 60 years, range 44–76) were enrolled in the study and subjected to DRE, TRUS and PSA assay. Patients with an alteration of one or more of the above-mentioned parameters (6 patients) underwent an echoguided biopsy (of nodule or normal). Only one (aged 52 years, PSA 12.1, DRE negative, TRUS small hypoechogenic area, prostatic volume 80 cc) had grade 2 PIN. Prostatectomy performed on the patient in another hospital showed that he had fibromyo-glandular hyperplasia. Results are discussed and compared with those reported in literature.

In literature it is estimated that only 20% of prostatic carcinoma are clinically important and indicators of biological aggressiveness of the neoplasm would therefore seem necessary. We considered 44 radical prostatectomies that were performed in our Division between 1989 and 1996. A histological section was selected for each patient on which the expression of C-erb B2 and p53 were tested with immunohistochemical methods. In these patients, who were homogeneous as far as surgical criteria are concerned, no subgroups with different progression were found.

Novel nonlinear fiber designs allow drastic reduction in dispersion variations. This removes a key obstacle to fiber-based parametric processes, which accumulate efficiently only if phase matched at each position along the fiber.

A 1.2-km timing-stabilized, polarization-maintaining fiber link based on balanced optical cross-correlation was demonstrated with ∼0.9 fs RMS timing jitter over 16 days and ∼0.2 fs RMS timing jitter over 3 days.

Single-frequency and narrow-linewidth pulse amplification is demonstrated in an erbium-doped higher-order mode fiber with effective area of 6000m2 and output long-period grating for re-conversion of the output beam back to the fundamental mode.

A partially bend-compensated index profile can accomplish robust single-modedness for fibers with A eff ∼1000μm2, much larger than conventional designs, and does not require asymmetric fabrication or oriented deployment.

We describe femtosecond laser systems optimized for high value applications in precision industrial micro-machining. Unprecedented system performance and reliability are enabled by novel fiber-optic architectures and integrated autonomous software control systems.

We report on recent development of core-and cladding-pumped multicore fiber amplifiers suitable for amplifying space division multiplexed signals. Amplification, noise properties of these amplifiers are shown, and scopes for further development will be discussed.

We demonstrate a 19-cell hollow core fiber with essentially single-mode propagation and 7.5 dB/km loss using a PRISM (Perturbed Resonance for Improved Single Modedness) design. This approach has potential for further loss reduction.

We demonstrate the first measured hollow-core fiber employing Perturbed Resonance for Improved Single Modedness (PRISM). The fiber has fundamental-mode loss of 7.5 dB/km, while other modes of the 19-lattice-cell core see loss >3000dB/km.

From September 1992 to February 1994, 1441 men aged between 50 and 70 years underwent screening with PSA and ER measurement for early diagnosis of prostatic carcinoma. A neoplasm was diagnosed in 1.73% (25/1441) of cases, which being found at an early stage, made it possible to perform prostatectomy and radical radiotherapy on 37.5% and 16.6% of patients respectively. The incidence of the disease was higher than in a previous screening with just ER dosage (1.73% vs 1.1%). Combined PSA and ER also gave higher sensitivity, specificity, overall accuracy and predictiveness compared to the methods taken individually. This combination seems preferable, in view of the greater efficacy and “practicability” compared to protocols which involve the use of USTR, which is less practicable on a large scale due to the length of time required and high costs. The utility of periodic determination of PSA levels in those over fifty years old is emphasised, both for oncological screening controls and to increase the diagnostic accuracy of other clinical tests.

Early-stage prostate cancer is usually asymptomatic and therefore, in the past, has often gone undetected, unless diagnosed by a digital rectal examination. Recently, in order to improve the detection of early stage disease, new tests have been introduced, namely prostate specific antigen and transrectal ultrasound. Considerable debate exists not only about the usefulness of the screening but also about the routine use of these tests. In this article the features of these tests, single or in combination are discussed, and how to perform follow-up of the patient already submitted to screening for prostatic carcinoma.

We perform detailed measurements of the higher-order-mode content of a low-loss, hollow-core, photonic-bandgap fiber. Mode content is characterized using Spatially and Spectrally resolved (S2) imaging, revealing a variety of phenomena. Discrete mode scattering to core-guided modes are measured at small relative group-delays. At large group delays a continuum of surface modes and core-guided modes can be observed. The LP11 mode is observed to split into four different group delays with different orientations, with the relative orientations preserved as the mode propagates through the fiber. Cutback measurements allow for quantification of the loss of different individual modes. The behavior of the modes in the low loss region of the fiber is compared to that in a high loss region of the fiber. Finally, a new measurement technique is introduced, the sliding-window Fourier transform of high-resolution transmission spectra of hollow-core fibers, which displays the dependence of HOM content on both wavelength and group delay. This measurement is used to illustrate the HOM content as function of coil diameter.

A cladding pumped multicore erbium-doped fiber amplifier for simultaneous amplification of 6 channels is demonstrated. Peak gain over 32 dB has been obtained at a wavelength of 1560 nm and the bandwidth measured at 20-dB gain was about 35 nm. Numerical modeling of cladding pumped multicore erbium-doped amplifier was also performed to study the properties of the amplifier. The results of experiment and simulation are found to be in good agreement.

The leading Alzheimer's disease (AD) therapeutics to date involves inhibitors of acetylcholinesterase (AChE), which should, in principle, elevate cholinergic signaling and limit inflammation. In spite of the effectiveness in 20%-30% of AD patients, more attention has been paid to find new anti-AChE agents from medicinal plants. Galanthamine, contained in the bulbs and flowers of Galanthus and related genera like Narcissus, represents a good example. The aim of this study is to review the role of possible AChE inhibitors (AChEI) present in plants traditionally used in European medicine for improving memory. Starting from Galanthamine, properties of Melissa species, Salvia officinalis, Arnica chamissonis and Ruta graveolens are discussed to point to the role of these plants as potential sources for the development of therapeutic agents for AD.

A new urea-containing metal-organic framework (MOF) was synthesized to act as a heterogeneous catalyst. Ureas are well-known for self-recognition and aggregation behavior, resulting in loss of catalytic competency. The catalyst spatial isolation achievable in a porous MOF environment suggests a potentially general solution. The combination of a symmetrical urea tetracarboxylate strut, 4,4'-bipyridine, and Zn(NO(3))(2)·6H(2)O under solvothermal conditions afforded a new microporous MOF (NU-601). This material is indeed an effective hydrogen-bond-donor catalyst for Friedel-Crafts reactions between pyrroles and nitroalkenes, whereas a homogeneous urea is much less competent. The higher rates of reaction of small substrates relative to larger ones with NU-601 strongly suggest that catalysis primarily occurs within the pores of this new material rather than on its exterior. To the best of our knowledge, this approach is the first example of specific engineering of successful hydrogen-bonding catalysis into a MOF material.

Random perturbations play an important role in the crosstalk of multicore fibers, and can be captured by statistical coupled-mode calculations. In this approach, phase matching contributes a multiplicative factor to the average crosstalk, depending on the perturbation statistics and any intentional heterogeneity of neighboring cores. The impact of perturbations is shown to be qualitatively different depending on whether they are gradually varying, or have short-length (centimeter-scale) variations. This insight implies a novel crosstalk suppression strategy: fast modulation of a bend perturbation by spinning the fiber can disrupt the bend-induced phase matching.

We demonstrate 2688-km multi-span transmission using wavelength-division multiplexing (WDM) of ten 50-GHz spaced 128-Gb/s PDM-QPSK signals, space-division multiplexed (SDM) in a low-crosstalk 76.8-km seven-core fiber, achieving a record net aggregate per-fiber-spectral-efficiency-distance product of 40,320 km·b/s/Hz. The demonstration was enabled by a novel core-to-core signal rotation scheme implemented in a 7-fold, synchronized recirculating loop apparatus.

Higher order modes for large-mode-area, high power fiber amplifiers are reviewed. Results from amplification of both CW and nanosecond pulsed signals in Er-doped HOM fibers with effective areas as large as 4000 μm2 are presented.

We demonstrate the first measured dual-hollow-core photonic bandgap silica fiber. We examine its bend-induced coupling characteristics both theoretically and experimentally. Varying the bend diameter of the fiber allows control of the resonant coupling wavelength.

We discuss the optical fiber properties and system impact of new transmission fibers, including low-loss ultra-large-area fibers for above 100-Gbit/s coherent systems, and multicore fibers for spatially multiplexed DWDM transmissions.

New fibers are being designed to carrying many spatially multiplexed signals, and thus drastically increase the capacity per fiber in long-haul communications. Current design research includes quite different approaches to managing the tradeoff between crosstalk and mode density. Fiber irregularity and length variation have a crucial on performance, and will ultimately determine the performance limits of space-division-multiplexing fibers.

Continuous wave and nanosecond pulse amplification in a higher-order-mode, Er-doped-fiber amplifier with 6000 μm2 effective area is demonstrated. Both 1480nm pump and 1560nm signal propagate in the LP 0, 14 mode.

From April 1989 to April 1994 we performed a mass-screening for early diagnosis of prostatic carcinoma (by D.R.E.) on 7303 men aged 50-79 years. Moreover we evaluated the prevalence of obstructive urinary symptoms and clinically significant B.P.H. We found a prevalence rate of benign prostatic hyperplasia of 17.3% (1259/7303). The most commonly found were incomplete bladder emptying, dribbling and weak stream force. The prevalence of urinary symptoms rose significantly with increasing age and prostate size (evaluated also by T.R.U.S. on 480 men). We haven't found clear correlations between BPH and occupational or environmental risk factors. Despite the good knowledge about the development of pathological B.P.H., there is little agreement about the definition of the clinical patterns of the disease. For Garraway, B.P.H. is an enlargement of the prostate gland for an equivalent weight >20 g. in the presence of symptoms of urinary dysfunction and/or a urinary peak flow rate < 15 ml/s. Our study presents some correlations with Garraway's experience, making use of clinical and morphological evaluations. A correct clinical and social interpretation of the disease will be feasible only by comparing populations with similar diagnostic and therapeutical patterns.

The authors have carried out a retrospective analysis of all patients who underwent radical prostatectomy during the last 3 years, to evaluate autologous blood predeposit in urological surgery. Even if all the patients underwent preoperative blood predeposit and on average 2.45 units were collected per patient, the patients transfused with homologous blood were 41.6%. To reduce the percentage of patients who are transfused with homologous blood, the authors believe that, accepting a haemoglobin threshold value of 11 g/dl in the immediate preoperative stage and through a blood letting programme, which respects the physiological time for the organism's recovery, it is possible to reach the goal of 4 bleedings in selective urological surgery. In this study, 4 units of autologous blood predeposit on average are able to cover 60% of the estimated losses.

Renal bacterial infection spans a continuum of severity from uncomplicated acute pyelonephritis to frank abscess formation. It can be a multi-focal process, with different portions of the kidney exhibiting different degrees of inflammation. The radiologic diagnosis of acute renal infections is based upon IVU, US and CT. In this investigation, the contribution of IVU, US and CT is evaluated in 3 patients with acute multifocal pyelonephritis and renal abscesses. The lack of specificity of IVU and the high false negative rate of US make them unsatisfactory diagnostic tools for patients clinically suspected of having multifocal pyelonephritis or renal abscess. CT is more sensitive for the detection of acute renal inflammatory diseases and for defining the extent of disease, thereby helping programme early and accurate therapy.

An increase in the incidence of prostate cancer can be expected in proportion to the increase in the elderly population, with a relative increase in expense. In our territory about Lit. 1,275,000,000 a year are spent on managing patients with the disease (0.6% of the total health service budget). Hospitalisation and medical treatment costs account for 49.2 and 41.6% respectively. On the one hand the wide-scale use of LH-RH analogues increases the social costs of the disease (also in comparison to countries like the U.S.A. and Sweden). On the other, it will perhaps produce a saving by lengthening the quiescent stage of the disease and by reducing post radical prostatectomy morbidity. Prostate cancer costs in Western countries will probably remain very high and will be conditioned by new diagnostic techniques, their widespread use and the types of treatment. After an initial increase in expense, early diagnosis (also through mass screening) and early, radical therapy with consequently reduced morbidity, may in the future provide a better quality of life at acceptable costs.

Fibers with asymmetrical bend compensation offer to completely remove the tradeoff between mode area and single-modedness, with potentially huge impact on high-power amplification. These fibers would be difficult to fabricate, but are the only fundamental-mode strategy that can remove the bend-distortion limitations on mode-area scaling. Here, we show that even imperfect fibers can achieve essentially complete HOM suppression for areas of 2000 square microns or larger. Ultimate performance limits due to finite cladding size and fabrication imperfections are calculated.

We demonstrate super-accurate fabrication of high Q-factor microresonators by nanoscale modification of the optical fiber radius and refractive index. The achieved fabrication accuracy is better than 2 angstroms in variation of the effective fiber radius.

We describe a new multicore fiber (MCF) having seven single-mode cores arranged in a hexagonal array, exhibiting low crosstalk among the cores and low loss across the C and L bands. We experimentally demonstrate a record transmission capacity of 112 Tb/s over a 76.8-km MCF using space-division multiplexing and dense wavelength-division multiplexing (DWDM). Each core carries 160 107-Gb/s polarization-division multiplexed quadrature phase-shift keying (PDM-QPSK) channels on a 50-GHz grid in the C and L bands, resulting in an aggregate spectral efficiency of 14 b/s/Hz. We further investigate the impact of the inter-core crosstalk on a 107-Gb/s PDM-QPSK signal after transmitting through the center core of the MCF when all the 6 outer cores carry same-wavelength 107-Gb/s signals with equal powers, and discuss the system implications of core-to-core crosstalk on ultra-long-haul transmission.

The Q-Tc interval duration on the electrocardiogram is recognized to differ between the sexes. In vitro data and data from humans before and after puberty and menopause suggest that sex hormones play a role in the longer Q-Tc intervals in women, or conversely, the shorter Q-Tc intervals in men. Direct investigations of sex hormone effects on the Q-Tc interval in humans, however, are limited and reach conflicting conclusions. Our objective was to determine effects of testosterone on ECG Q-T intervals of older men and older women. ECG's from 84 older men and older women in double-blind placebo-controlled investigations of testosterone supplementation for the treatment of chronic heart failure (CHF) were analysed. Thirty men received 1000mg intramuscular long-acting testosterone undecanoate and 28 men received saline at 0, 6 and 12weeks. ECG's were recorded at baseline and 12weeks. Sixteen women received transdermal testosterone (33μg) and 10 women received matching placebo twice weekly for 24 weeks with ECG's at baseline and after 24weeks. Testosterone, but not placebo, shortened Q-T and Q-Tc intervals without heart rate changes. Q-T intervals decreased from 385±28 (mean±SD) to 382±28 ms (p0.002) and Q-Tc intervals decreased from 398±26 to 392±27 (p0.006) in men on testosterone. In women, Q-T intervals decreased from 400±25 to 397±23ms (p=0.06) and Q-Tc intervals from 415±26 to 409±27ms (p=0.3) on testosterone. Q-T intervals were longer in women compared with men under all conditions (p0.03). The data support a direct effect of testosterone to shorten Q-T intervals in older men and older women in the absence of HR changes or hypogonadal status. Mean decreases are small and unlikely to affect risks of arrhythmic events in patients receiving Q-T prolonging medications.

Spatially resolved spectral interferometry is used to measure the mode content of a Yb-doped photonic-crystal fiber rod amplifier with a 2300 μm(2) mode area. The technique, known as S(2) imaging, was adapted for the short fiber amplifier at full power and revealed a small amount of a copolarized LP(11) mode. Simulations illustrate the potential for weak mode suppression in this fiber and agree qualitatively with the measurements of S(2) and M(2). Higher-order-mode content depends on the alignment of the input signal at injection and ranged from -18 dB for optimized alignment to -13 dB when the injection alignment was offset along the LP(11) axis by 30% of the 55 μm mode-field diameter.

Achieving low crosstalk and high core density is one of the key challenges for multicore fibre. Advanced low-crosstalk designs aim for optimal mode confinement and additional phase-mismatch suppression robust to variations.

A record capacity of 112 Tb/s with 14-b/s/Hz aggregate spectral efficiency is transmitted over a 76.8-km seven-core-fiber using space-division multiplexing. Each core carries 160 107-Gb/s PDM-QPSK channels on a 50-GHz grid in the C and L bands.

We report the first experimental demonstration of space-division-multiplexed DWDM transmission of PDM-QPSK channels over a multicore fiber. A total capacity of 56-Tb/s (7×80×107-Gb/s) is transmitted over a 76.8-km seven-core-fiber with a record spectral-efficiency of 14-b/s/Hz.

Spatially and spectrally resolved mode imaging of a 19 cell photonic bandgap fiber with minimum loss at 1550 nm is demonstrated using a high resolution tunable laser and phosphor-coated CCD camera.

We experimentally demonstrate series of identical two, three, and five coupled high Q-factor Surface Nanoscale Axial Photonics (SNAP) microresonators formed by periodic nanoscale variation of the optical fiber radius. These microresonators are fabricated with a 100 \mum period along an 18 \mum radius optical fiber. The axial FWHM of these microresonators is 80 \mum and their Q-factor exceeds 107. In addition, we demonstrate a SNAP microresonator with the axial FWHM as small as 30 \mum and the axial FWHM of the fundamental mode as small as 10 \mum. These results may potentially enable the dense integration of record low loss coupled photonic microdevices on the optical fiber platform.

Dense photonic integration promises to revolutionize optical computing and communications. However, efforts towards this goal face unacceptable attenuation of light caused by surface roughness in microscopic devices. Here we address this problem by introducing Surface Nanoscale Axial Photonics (SNAP). The SNAP platform is based on whispering gallery modes circulating around the optical fiber surface and undergoing slow axial propagation readily described by the one-dimensional Schr\"odinger equation. These modes can be steered with dramatically small nanoscale variation of the fiber radius, which is quite simple to introduce in practice. The extremely low loss of SNAP devices is achieved due to the fantastically low surface roughness inherent in a drawn fiber surface. In excellent agreement with the developed theory, we experimentally demonstrate localization of light in quantum wells, halting light by a point source, tunneling through potential barriers, dark states, etc. This demonstration, prototyping basic quantum mechanical phenomena with light, has intriguing potential applications in filtering, switching, slowing light, and sensing.