Compact and low-latency instantaneous frequency measurement using 38 cm bismuth-oxide fiber and fiber Bragg gratings

We demonstrated a compact and low-latency photonic approach for broadband RF signal frequency measurement. The photonic approach does not require high-speed electronics for gigahertz RF signal measurement. Frequency-to-intensity mapping is achieved based on a two-tap finite-impulse-response filter architecture, where the time delay between signals is provided by fiber Bragg grating array. With four-wave mixing (FWM) as an optical broadband mixer, sinusoid frequency response is transferred to a DC output, where FWM is achieved in a 38 cm bismuth-oxide fiber. Thus, the resultant signal does not consist of any high-frequency component and no high-speed oscilloscope is needed for the measurement.