High performances of very long (13.5mm) tapered laser emitting at 975nm
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 realised a multi-section monolithic-cavity tapered laser diode with a record cavity length of 13.5 mm. The laser operates at 975 nm wavelength. It is designed for the emission of ultra-short optical pulses (<1 ps) at a repetition rate of 3 GHz with an average optical power of 600 mW. 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. The first results obtained under CW pumping of such centimetre-long laser at 20 degrees C heatsink temperature show the lasing threshold current as low as 1.27 A and the differential external efficiency as high as 0.55 W/A.