Lasing dynamics of very long (13.5mm) tapered laser emitting at 975 nm

Mode-locked semiconductor laser technology is a promising technology candidate considered by European Space Agency (ESA) for optical metrology systems and other space applications in the context of high-precision optical metrology, in particular for High Accuracy Absolute Long Distance Measurement. For these applications, we have designed, realized and characterized a multi-section monolithic-cavity tapered laser diode with a record cavity length of 13.5mm. The laser operates at 975nm wavelength with average output power up to 600mW. It is based on a MOVPE grown laser structure with Aluminium free active region enabling high optical gain, low internal losses and low series resistance. It reaches passive mode-locking operation on fundamental cavity round trip frequency of 2.88GHz with chirped pulse width of 6.2ps and time bandwidth product of 8 for the average output power of 250mW. Alongside with passive mode-locking operation, we discuss other lasing regimes in these very long tapered lasers.