Fig. 1: Vibration cancellation concept.
From: Magic cancellation point for vibration resilient ultrastable microwave signal synthesis
a The vibration canceled ODFD system comprises SBS laser light generated along the two orthogonal polarization axes of fiber (slow and fast) and heterodyned against two comb lines. A vibration applied to the system causes the two SBS lasers to fluctuate in the same direction with equal magnitude. b The SBS lasers and the comb lines interfere to produce two separate beat notes at microwave frequencies. The beat notes fluctuate via the applied vibration, with the polarity of the movement dependent on which comb lines form the beat (shown here to be in the same direction). c The two RF beat notes are sent to a mixer, and the difference frequency is selected. The applied vibration is canceled in the resulting difference, thereby yielding no fluctuation of the RF tone. d The comb lines, formed by electro-optic modulation at a frequency frep, are stabilized to the RF difference frequency, suppressing the effects of vibration on the derived microwave signal.
