Electrically wavelength adjustable DBR laser for background-free Raman spectroscopy at 785 nm
An electrically wavelength tunable DBR ridge-waveguide laser suitable for multi-wavelength excitation Raman spectroscopy near 785 nm is presented. The 3 mm long device consists of a 2.2 µm wide ridge waveguide and a 10th order DBR surface grating. Resistors implemented near the grating enable flexible wavelength tuning by Joule heating. At 25°C heat sink temperature, laser emission with 100 mW optical output power and a spectral width of 20 pm is obtained. A current of 0.6 A applied to the resistors results in 2.2 nm wavelength tuning. Single emission wavelengths can be adjusted with time constants of about 500 ms.
André Müller received his Ph.D. degree in Photonics Engineering from the Technical University of Denmark in 2013 for his work on suitable methods for power scaling of frequency converted diode lasers. He then joined Ferdinand-Braun-Institut gGmbH where he is still working in the field of diode lasers and micro-integration of optical components for diode laser based light sources for spectroscopic applications.