Research On Microwave Photonic Filter And Its Sensing Technology Based On Tilted Fiber Grating

With the continuous development of information science and technology,optical systems are gradually used to process microwave signals.Under this background,an emerging discipline that combines microwave and photonics came into being.Microwave photonics has been widely used in various fields,and microwave photonic filters are an important research field in microwave photonics.Combining optics and microwave devices can achieve the purpose of processing radio frequency signals in the optical domain,and has the characteristics of large bandwidth and resistance to electromagnetic interference.In this paper,we use the special spectral structure of tilted fiber grating,propose a new structure of microwave photonic filter.Through theoretical simulation,we study the influence of key devices and their core parameters on system performance,and we designed experiments to verify the theoretical analysis results,and the experimental results confirmed that they were in good agreement with the theoretical analysis.Further,we verify the tunability of the microwave photonic filter of this structure,test the linear range of the system,and evaluate the performance of this filter.On the other hand,the application of microwave photonic filter technology to the field of optical fiber sensing has become a new research hotspot in recent years.Traditional fiber Bragg grating sensors usually use a spectrum analyzer to realize demodulation in the optical domain,and realize sensor measurement by detecting changes in wavelength with temperature and other external conditions.In fact,a small change in the optical wavelength in the optical domain will cause a large change in microwave frequency.Compared with a spectrum analyzer,an electric spectrum analyzer has better resolution,so sensors based on microwave photonic technology can greatly improve the resolution of sensory measurement.Based on this,this paper studies the experimental scheme of temperature sensing using the microwave photonic filter of this structure.As the temperature changes,the overall spectrum will be shifted,resulting in the change of the center frequency of the microwave photonic filter.Therefore,we can achieve the purpose of temperature sensing.