title: Saturated gain spectrum of VECSELs determined by transient measurement of lasing onset.
abstract: We describe time-resolved measurements of the evolution of the spectrum of radiation emitted by an optically-pumped continuous-wave InGaAs-GaAs quantum well laser, recorded as lasing builds up from noise to steady state. We extract a fitting parameter corresponding to the gain dispersion of the parabolic spectrum equal to -79 ± 30 fs2 and -36 ± 6 fs2 for a resonant and anti-resonant structure, respectively. Furthermore the recorded evolution of the spectrum allows for the calculation of an effective FWHM gain bandwidth for each structure, of 11 nm and 18 nm, respectively.
authors.forename: C Robin
authors.initials: CR
authors.lastname: Head
authors.forename: Keith G
authors.initials: KG
authors.lastname: Wilcox
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Turnbull
authors.forename: Oliver J
authors.initials: OJ
authors.lastname: Morris
authors.forename: Edward A
authors.initials: EA
authors.lastname: Shaw
authors.forename: Anne C
authors.initials: AC
authors.lastname: Tropper