A widely tunable multiwavelength single-longitudinal-mode fiber laser based on Rayleigh and Brillouin scattering effects is proposed and experimentally demonstrated. The amplified Rayleigh backscattering of seed light serves as the original Brillouin pump while the Rayleigh and Brillouin scattering in the single mode fiber provide randomly distributed feedback. When the seed light wavelength varies in C-band with the power of −8 dBm, the fiber laser can generate more than nine lasing lines with narrow linewidth and their maximum power fluctuation is less than 2.4 dB. The lasing lines are stable, rigidly separated by 10.852 GHz.
We present a scheme for on-chip optical mode conversion in a hybrid photonic-phononic waveguide. Both
propagating optical and acoustic wave can be tightly confined in the hybrid waveguide, and the acoustooptical
interaction can be enhanced to realize optical mode conversion within a chip-scale size. The
theoretical model of the acousto-optic interaction is established to explain the mode conversion. The
numerical simulation results indicate that the high efficient mode conversion can be achieved by adjusting
the intensity of the acoustic wave. We also show that the mode conversion bandwidth can be dramatically
broadened to 13 THz by adjusting the frequency of the acoustic wave to match phase condition of the
acousto-optic interaction. This mode converter on-chip is promising in order to increase the capacity of
silicon data busses for on-chip optical interconnections.