Abstract

Over the last decade, fibre-based devices incorporating single or multiple linear directional couplers have been the subject of theoretical and experimental investigation. These include fibre resonators [1-6] and linear [4] and nonlinear [7] loop mirrors. Except in [6] and [7], the devices involve linear propagation of a continuous wave (cw) or long pulse input. Only [7] studies operation with narrow pulses. Fibres have been incorporated in laser systems since the development of the soliton laser [8]. Recently, lasers with rare earth doped (neodymium [9] or erbium [10]) fibres as the active medium have been developed. All the above laser systems involve linear coupling to and from the fibre.

© 1991 Optical Society of America