STABILITY FACTORS FOR TUNEABLE MULTI-SECTION SEMICONDUCTOR LASERS

A method is described for qualifying a multisection semiconductor laser using measurements of excursions from stable operating conditions to neighbouring mode boundaries at which the laser undergoes mode-hopping. These excursions are measured when the laser is characterised to provide a measure of the stability and hence the quality of the laser, and to facilitate statisctical analysis of the quality of a batch of lasers from a given wafer. The values of the excursions may be re-measured during the life of the laser using a curtailed version of the characterising procedure rapidly to monitor aging or other deterioration of the laser.