Advancing the optical feed back concept: Grating enhanced external cavity diode laser

We present theoretical and experimental investigations on a new optical feedback concept for single mode diode lasers. It is based on the optical feedback from a resonant external cavity coupled to the diode laser through the 1st order diffraction of a grating. With a single mode diode laser operating at 852 nm we demonstrate a short term line width of less than 60 kHz, an overall tuneability in excess of 36.4 nm and a continuous tuning range in excess of 45 GHz, both at constant diode temperature.