Power-Independent Microwave Instantaneous Frequency Measurement Based on Combination of Brillouin Gain and Loss Spectra

Abstract

Photonics-assisted microwave instantaneous frequency measurement (IFM) is considered as a promising technique for detecting an unknown radiofrequency (RF) signal, which has advantages of broad frequency measurement range and fast processing speed. Up to date, there is no photonics-assisted IFM system that can essentially measure an unknown RF signal timefrequency information with power fluctuating seriously. Moreover, the measurement accuracy and frequency modulation recognition are not as good as those of traditional electronic methods. Here, we propose an IFM scheme based on the combination of Brillouin gain spectrum (BGS) and Brillouin loss spectrum (BLS), which is RF-power-independent with high measurement efficiency. The combination of BGS and BLS to construct the amplitude comparison function (ACF) can reduce the influence of RF signal power fluctuation within 21.27 dB by single-shot measuring. When an appropriate frequency interval with frequency domain monotonous power of microwave comb signal is modulated on the pump lightwave, the IFM accuracy of the unknown signal reaches about 1 MHz. After the initial calibration of the system, it can recognize the time-frequency variation of single tone signal, linear frequency modulated signal (LFM), nonlinear frequency modulated signal (NLFM), and Costas signal. This scheme will help to promote the application of the IFM in the field of spectrum reconnaissance and reception.

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

“…This is confirmed by the materials presented in this review and was determined by a large amount of recent publications devoted to integrated implementations of photonic systems [80][81][82][83]. (3) An overview of existing works on IFM systems shows that they also cover the issues of the instantaneous frequency measurement of multiple microwave signals simultaneously [4,37,39,49,84,85], linear frequency-modulated signals [86][87][88], pulse signals [89,90] and other special types of signals [87,88,90] that use frequency and amplitude discriminators of resonance type. Such issues are among the most important areas for research into the construction of a fully functional photonic radar.…”

Broadband Microwave Photonic Frequency Measurement Based on Optical Spectrum Manipulation and Stimulated Brillouin Scattering

“…Compared with electronic technology, microwave photonic technology has incomparable advantages on its well-known features, such as high frequency, wide band, immunity to electromagnetic interference and small size [5], [6]. In recent years, this technology has been extensively researched, and the frequency measurement based on it has attracted much attention [7]- [10].…”

“…The principle of the frequency measurement method based on SBS [9], [10], [17], [27], [28] is that the SBS is used to generate selective gain or loss on the first-order sideband of phase-modulated signal which is related to the frequency of the signal to be measured, so as to complete the PM-to-AM conversion, build the mapping relationship between frequency and power, and finally obtain the frequency to be measured by detecting the microwave signal power after frequency beating. .…”