of the rf input signal to the receiver as such the reference lock module 208 and the single rf mode optical loop 212 form an oscillator having a resonant frequency at the frequency set by the frequency control signal thus the filter 206 is coarsely tuned to the expected frequency of the rf input once the filter 206 is locked to the reference signal and oscillating at the selected frequency the filter 114 switches to the signal lock mode wherein the controller opens the second rf switch 204 and closes the first rf switch 200 in this manner the rf input signal is coupled to the signal lock module 210 and the rf reference signal is disconnected from the reference lock module 208 in the signal lock mode the signal lock module 210 uses the rf input signal to finely tune the filter 206 to center upon the frequency of the rf input signal the combination of the signal lock module 210 and the single rf mode optical loop 212 form a high q bandpass filter centered at the center frequency of the rf input signal the filter can be rapidly retuned to another signal by switching to the reference lock mode and using the controller to change the operating frequency of the reference lock module for example in a radar application the radar transmission signal may be used as the reference signal to coarsely lock a rf photonic filter to the frequency of transmission the reflected signal from an object will have a frequency that is slightly higher or lower than the frequency of transmission during signal lock mode the reflected rf signal is rapidly.