An arbitrary wavelength tuning technique of microcavity lasers in a wide band range

In this paper, a Raman laser is proposed based on a high-Q silica microcavity, and arbitrary wavelength tuning is realized by fine and coarse tuning. The mechanical tuning range is extended to 5.5 GHz by designing the geometry of the microcavity. Axial discrete tuning in a wideband range is achieved by coupling different transverse modes. The wavelength of the Raman laser is tuned arbitrary in a range of 38.6 nm with the tuning accuracy about 50 MHz. This study extends the application of microcavity Raman laser to the field of tunable lasers and high dynamic range sensors.