Photonic doppler velocimetry (PDV) system for ultra-high-speed instantaneous measurement

A photonic doppler velocimetry (PDV) system for ultra-high-speed instantaneous measurement, comprising:

• a laser velocity interferometry module;
• a microwave photonic module;
• and
• a data acquisition and signal processing module;
• wherein the laser velocity interferometry module comprises a continuous wave laser, a circulator, a fiber optic probe, and a first photodetector;
• the continuous wave laser is connected to a first port of the circulator;
• a second port of the circulator is connected to the fiber optic probe;
• and a third port of the circulator is connected to the first photodetector;
• the microwave photonic module comprises a femtosecond-pulse laser, a first dispersion optical fiber, a second dispersion optical fiber, a Mach-Zehnder (M-Z) modulator, and an optical fiber amplifier;
• the femtosecond-pulse laser is connected to the first dispersion optical fiber;
• the first dispersion optical fiber is connected to the M-Z modulator;
• the M-Z modulator is connected to the second dispersion optical fiber;
• the second dispersion optical fiber is connected to the optical fiber amplifier;
• the data acquisition and signal processing module comprises a second photodetector, an oscilloscope, and a computer;
• the second photodetector is connected to the oscilloscope;
• the oscilloscope is connected to the computer;
• and
• the laser velocity interferometry module further comprises an electrical amplifier, an electrical filter and a power divider;
• the first photodetector is connected to the electrical amplifier;
• the electrical amplifier is connected to the electrical filter;
• the electrical filter is connected to the power divider;
• a 0° phase-shift electrical signal of the power divider is connected to a first port of the M-Z modulator, and a 90° phase-shift electrical signal of the power divider is connected to a second port of the M-Z modulator;
• and the optical fiber amplifier is connected to the second photodetector.