Optical amplifier arrangement

摘要

An optical amplifier (10) which integrates a pre-amplifier (46) and a power amplifier (48) in a single rectangular active medium (14) to enable amplification of low power ultra-short pulses to optimal power levels. A seed beam passes through the amplification medium along a first pre-amplification path (32) making multiple traverses of the medium. It is imaged back along the first path to make a double pass of the medium as a pre-amplifier. The beam is then re-imaged into the medium again on a second power amplification path, making multiple traverses of the medium in a single pass. The paths are different but overlap so that efficient power extraction is achieved. Embodiments based on all passive components are described.