Active optical frequency standard based on narrow bandwidth Faraday atomic filter

Active optical frequency standard based on narrow bandwidth Faraday atomic filter is proposed. The output laser power achieved to 42 μW. The laser frequency is determined by narrow bandwidth Faraday atomic filter, corresponding to the Cs 6²S_1/2 F=4 to 6²P_3/2 F´=4, 5 crossover transition line. The transmission of the Faraday atomic filter is 23% and the bandwidth is 52.6MHz. Considering the loss in the cavity, the linewidth of the cavity mode is 345.1MHz. The bad cavity coefficient is 6.6. Working in the bad cavity scheme, the output laser signal of active Faraday optical frequency standard is insensitive to the cavity vibration and thermal noise. Besides, we redesign an integrated structure to decrease the influence of the environmental vibration. With more steady structure, hundreds of millihertz level of the active Faraday optical frequency linewidth is expected.