title: Self-validating technique for the measurement of the linewidth enhancement factor in semiconductor lasers.
abstract: A new method for measuring the linewidth enhancement factor (α-parameter) of semiconductor lasers is proposed and discussed. The method itself provides an estimation of the measurement error, thus self-validating the entire procedure. The α-parameter is obtained from the temporal profile and the instantaneous frequency (chirp) of the pulses generated by gain switching. The time resolved chirp is measured with a polarization based optical differentiator. The accuracy of the obtained values of the α-parameter is estimated from the comparison between the directly measured pulse spectrum and the spectrum reconstructed from the chirp and the temporal profile of the pulse. The method is applied to a VCSEL and to a DFB laser emitting around 1550 nm at different temperatures, obtaining a measurement error lower than ± 8%.
authors.affiliation: Departamento de Tecnología Fotónica, Universidad Politécnica de Madrid, ETSI de Telecomunicación, Ciudad Universitaria 28040 Madrid, Spain. antonio.consoli@tfo.upm.es
authors.forename: Antonio
authors.initials: A
authors.lastname: Consoli
authors.forename: Borja
authors.initials: B
authors.lastname: Bonilla
authors.forename: Jose Manuel G
authors.initials: JM
authors.lastname: Tijero
authors.forename: Ignacio
authors.initials: I
authors.lastname: Esquivias
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000295:instrumentation* / Q000379:methods*; D054023:Lasers, Semiconductor