A Scheme of Instantaneous Frequency Measurement with High Precision Assisted by Photonics

Abstract

In modern complex battlefield environment, it is important to obtain the frequency spectrum precisely. We propose an operational method of instantaneous frequency measurement (IFM) assisted by photonics, which can achieve high precision based on stimulated Brillouin scattering (SBS), giving the credit to the narrow linewidth of gain spectrum of SBS. We use MZM and DPMZM cascade to generate a tunable continuous optical signal and modulate the measured signal to the continuous optical signal and a DPMZM is used to generate pump light, the two beams of light are injected into the fiber, the stimulated Brillouin scattering (SBS) effect occurs in the optical fiber and the Brillouin gain spectrum (BGS) is formed. By setting the scanning frequency, the Brillouin gain varies with frequency and the amplitude comparison function (ACF) can be formed in the narrow line band of BGS. And the measurement of full frequency band is realized through a reference signal, the measured frequency range is limited only by photoelectric device. Estimation of multiple radio-frequency (RF) signals can also be achieved with a resolution of 250 MHz. In the numerical simulation, the average measurement error less than 1 MHz is achieved in this scheme.

Photonic-Assisted Receivers for Instantaneous Microwave Frequency Measurement Based on Discriminators of Resonance Type

“…The change in f P allows for scanning with the gain and loss contours of the harmonics of the measured frequencies positioned between the lowest and highest values of the pump laser tuning frequency, which determines the operational frequency range. After amplification/absorption, the signal power is received at the photodetector and its frequency is determined through the ACF of the corresponding sub-band, though the slope of the ACF curve is roughly the same for each channel [40].…”

“…The key differences between implementation methods lie in the choice of the physical effect and the resonance type discriminator, which are the basis of IFM implementation. According to the measurement method, there are systems based on a fiber Bragg grating (FBG) [23][24][25][26][27], FBG with a phase shift (PS-FBG) [28][29][30][31], an optical microring resonator (MRR) [32][33][34][35][36], stimulated Brillouin scattering (SBS) [4,[37][38][39][40] and Fano resonance [41].…”