Dual pump brillouin laser for RoF millimeterwave carrier generation with tunable resolution

Conventional Brillouin based carrier generator may produce optical wavelengths at the spacing of 10 GHz (odd) or 20 GHz (even), which in turn will be heterodyned for microwave/millimeter wave (mm-wave) generation. Therefore, in the scenario where both odd and even order carriers are required, two laser units have to be utilized. In this paper, a new type of Brillouin fiber laser is proposed with bidirectional pumping by using two seed lasers. This technique enables single laser unit to generate both odd and even order wavelengths that results in the possibility of varying the resolution of the laser. The laser resolution can be changed by switching the seed laser 2 OFF for even order carrier generation, while the odd order carrier generation can be performed by operating the seed laser 2 at the same wavelength as seed laser 1. A ~30 GHz carrier generation was performed in the proposed laser unit by switching to odd order generation. Meanwhile, a 40 GHz carrier was generated by both odd and even order options of the laser, where the odd order exhibits a power level of -7 dBm with many residual components, while the even order generated high purity carrier with a power level of 8 dBm, resulting in an improvement 15 dB.