Coexisting periodic attractors in injection locked diode lasers

We present experimental evidence for coexisting periodic attractors in a semiconductor laser subject to external optical injection. The coexisting attractors appear after the semiconductor laser has undergone a Hopf bifurcation from the locked steady state. We consider the single mode rate equations and derive a third order differential equation for the phase of the laser field. We then analyze the bifurcation diagram of the time periodic states in terms of the frequency detuning and the injection rate and show the existence of multiple periodic attractors.Comment: LaTex, 14 pages, 6 postscript figures include

Industry Representational Organisations and Market Reforms in Selected Coffee Producing Countries

Liberalisation of developing country agricultural markets has created a need for industry representative organisations (IROs), both to articulate industry concerns to government and to aid in implementation of sector policies. We consider the roles of IROs is a group of African coffee producing countries, and examine the extent to which pre-existing parastatal organisations have been able to fulfil these functions. We also compare the effectiveness of these organisations with their longer established Latin America counterparts, and ask to what extent the Latin American experience is replicable in Africa. The paper makes recommendations with regard to future roles for IROs. This paper is based on a study undertaken by Gilbert and ter Wengel for the World Bank and the Common Fund for Commodities (CFC). We are grateful to Jan van Hilten and Rob Simmons for comments on the initial draft of the paper. The views expressed are those of the authors alone, and not those of either the World Bank or the CFC. (Résumé d'auteur