Patent ID: 7957436

Claim:
A laser for generating laser light pulses comprising: a cavity having a ring topology containing an active optical gain medium and spectral filtering means for limiting the bandwidth of light passing through the gain medium; delay means for delaying light by a predetermined delay time (Δt); means for extracting a portion of laser light from the cavity, launching said portion into said delay means and returning the delayed portion to the optical gain medium; control means operable to activate the gain medium for a first time period to produce a first laser light pulse (LP 1 ) having a duration that is less than the delay time (Δt), and activate the gain medium for a second time period while said portion of the first light pulse that has been delayed by the delay means is traversing the gain medium, thereby to produce a second laser light pulse (LP 2 ) having a shorter duration and faster risetime than the first laser light pulse (LP 1 ); and output means for outputting the second laser light pulse (LP 2 ).