Laser pumped atom frequency standard with a high frequency stability

摘要

PURPOSE:To stabilize an output micro wave frequency for a long time by sweeping the frequency of a phase modulation micro wave impressed on a light/micro wave double resonance part, integrating the synchronous detection output of a transmission pumping optical strength in the resonance part, which is outputted in correspondence with the frequency, and controlling the frequency of a laser so that the integrated value comes to zero. CONSTITUTION:An output VPSD from the synchronous detector 8 is inputted to an arithmetic and control unit 11 through an A/D converter. Since the arithmetic and control unit 11 sweeps back and forth the frequency of the micro wave impressed on a micro wave cavity resonator 3 with a resonance frequency as a center, a voltage impressed on a voltage control crystal oscillator 5 is changed and VPSD which is inputted in correspondence with the sweeping of the frequency of the micro wave is integrated. Since the integrated value corresponds to a value showing asymmetry, the value is fed back to the current source for driving laser 10 through the D/A converter, a current injected to the laser 1 is changed and the integrated value is set to zero when the integrated value is not zero. Thus, the micro wave resonance frequency can be stabilized for a long time.