A novel method of increasing the range of 1.65µm OTDR using a Q-switched erbium fibre laser

This paper demonstrates a novel method of increasing the range of a 1.65µm optical time domain reflectometer system (OTDR). OTDR measurements at 1.65µm are more sensitive to fibre macro and micro bending losses than those produced at wavelengths 1.3 and 1.55µm. This enables problems to be identified in their early stages reducing the risk of total system failure. However, the dynamic range of current 1.65µm OTDR systems

158µJ pulses from a single transverse mode, large mode-area EDFA

We report the amplification of 10pJ-100pJ, semiconductor diode pulses up to an energy of 158µJ and peak powers >100kW in a multi-stage fibre amplifier chain based on a single-mode, large mode-area erbium doped amplifier design. These results represent the highest single-mode pulse energy ever extracted from any doped fibre system

Erbium fibre laser pumped nanosecond optical parametric oscillator

We report a periodically-poled lithium niobate optical parametric oscillator pumped by a frequency doubled Q-switched erbium-fibre laser. Pump tuning of the OPO signal with thresholds below 10µJ was demonstrated. Signal tuning range was 0.99-1.45µm

Study of linearly-chirped fibre gratings

Fibre gratings are proving to be one of the most important devices in a number of optoelectronic applications. They basically constitute generalised Bragg reflectors with well designed, adjustable reflection and dispersion characteristics. They can be used effectively for dispersion compensation in high-bit-rate, long-haul fibre-optic communication links, as well as, for the implementation of a variety of high quality fibre-optic laser cavities of various geometries. In this paper, we investigate thoroughly the reflective and dispersive properties of linearly chirped fibre gratings for use, particularly, in dispersion-management applications, such as dispersion compensation in communication links and short-pulse manipulation

Simulation of 50GHz over 50km of standard fibre using mid-point spectral inversion for dispersion compensation

Transmission of 6ps linear pulse pairs over 50km of standard fibre is demonstrated by employing midpoint spectral-inversion (phase conjugation) of the data signal to compensate dispersion effects. Pulse broadening as low as 10% and faithful reconstruction of the pulse patterns is observed and confirms the applicability of this technique to bit-rates grater than 100 Gbits

The effect of an interactive tutorial on the prescribing performance of senior medical students

Objectives: To evaluate the effectiveness of small group tutorials in teaching senior medical students the requirements of prescription writing. Design: Random allocation to interactive tutorial or didactic lecture with blinded evaluation. Subjects: All 1999 6th year medical students, the University of Adelaide. Results: The Tutorial Attenders (mean 13.3, SD 2.6) performed significantly better than the Lecture Group (mean12.2, SD 3.0) p=0.041 and the Non-attenders (mean10.7, SD 3.1) p=<0.001. The 13 individual OSCE items formed four logical subgroups, and the Tutorial Attenders performed significantly better in Prescription Writing in all comparisons. Conclusion: A single, one-hour interactive tutorial is likely to be the minimum amount of intervention that will be effective in improving prescribing skills.Anne L Tonkin, David Taverner, Jenny Latte, Christopher Doeck

High-power chirped-pulse all-fiber amplification system based on large-mode-area fiber gratings

The fabrication of large mode-area single mode fibres are crucial to developing high power all-fibre lasers and amplifiers. We report the amplification of picosecond pulses to microjoule energy levels and pulse peak powers in excess of 500kW in an all fiber Chirped Pulse Amplification (CPA) system based on novel large mode area fiber components

Experimental investigation of picosecond pulse reflection from fibre gratings

The dispersion of picosecond pulses on reflection from efficient photorefractive fiber gratings is explored experimentally. Unlike simple measurements of reflectivity, this approach allows both the amplitude and the phase of the grating response to he probed as a function of frequency

Interaction of N solitons in the massive Thirring model and optical gap system: the Complex Toda Chain Model

Using the Karpman-Solov''ev quasiparticle approach for soliton-soliton interaction I show that the train propagation of N well separated solitons of the massive Thirring model is described by the complex Toda chain with N nodes. For the optical gap system a generalised (non-integrable) complex Toda chain is derived for description of the train propagation of well separated gap solitons. These results are in favor of the recently proposed conjecture of universality of the complex Toda chain.Comment: RevTex, 23 pages, no figures. Submitted to Physical Review

Experimental demonstration of intermodal dispersion in a two-core optical fiber

The recent prediction that intermodal dispersion can play a significant role in pulse evolution in a two-core optical fiber was confirmed experimentally. A picosecond pulse at 1.548µm launched into one core of a meters-long two-core fiber was found to come out of either core of the fiber as two temporally separate pulses. By measuring the time delay between these two pulses, the intermodal dispersion in the fiber was estimated to be 1.13ps/m, in good agreement with theory