Temperature characteristics of surface micromachined MEMS-VCSEL with large tuning range

Several Applications for tunable laser diodes have strict constraints in terms of overall power consumption. Furthermore, the implementation in harsh environments with large temperature fluctuations is necessary. Due to the constraint in power consumption, the application of active cooling might not be an option. For this reason we investigate the temperature characteristics of an electrically pumped MEMS-VCSEL with wide continuous wavelength tuning. For the first time, a mode hop free single mode (side mode suppression ratio (SMSR) > 40dB) tuning range of 45nm at 70°C is demonstrated with a MEMS-VCSEL. An increase of the tuning range from 85nm at 20°C to 92nm at 40°C is measured and explained. In contrast to fixed wavelength VCSEL, the investigated device shows a negative temperature induced wavelength shift of -4.5nmK(-1), which is caused by the MEMS-mirror. At 1560nm, the fibre-coupled optical output power is above 0.6mW over the entire temperature range between 20°C to 70°C and shows a maximum of > 3mW at 20°C.