Internally generated 21.6-GHz millimeter wave based on brillouin fiber laser

An all-optically generated millimeter wave carrier at 21.67 GHz is experimentally achieved. This frequency is realized when two consecutively generated laser wavelength are heterodyned on the 60 GHz high-speed photodiode. The mixing between the Brillouin pump and the second-order Stokes wavelengths is spaced by 1.7 nm. This spacing, which is doubled from inherently generated Stokes shift, is accomplished through the isolated circulation of the first order Stokes wave in the double Brillouin Stokes shifter built with 25-km single mode fiber. The generated millimeter carrier is measured at 21.68 GHz, and its carrier phase noise and threshold power are -58.67 dBc/Hz and 19 mw of Brillouin pump power respectively.