Research On New-type Phase-Shifted Fiber Bragg Gratings And Their Applications

In recent years,as the application demand extends,fiber systems and fiber devices are required to operate in extreme environments,especially in the high-temperature environment.Phase-shifted fiber Bragg gratings(PSBGs),as outstanding in-fiber bandpass filters and wavelength selectors,have attracted extensive attention in the fields of optical communications,fiber lasers,and optical sensing.However,most conventional PSBGs can not survive under the high temperature.Aiming at the problem,we propose two different types of new-type PSBGs.One is phase-shifted type-IIa fiber Bragg grating(PSBG-IIa),and the other is super-structure phase-shifted fiber Bragg grating.First,PSBG-IIa is achieved by a two-step fabrication technology named as the structure-breaking method.The notch signal within the stopband is as narrow as 4.8 pm,which could be designed and adjusted flexibly by controlling the phase-mask translation precisely.Then the PSBG-IIa is inserted into the cavity structure of a distributed Bragg reflector(DBR)fiber laser.Due to PSBG-IIa's high-temperature resistance as well as the narrowband notch,the DBR fiber laser is enabled to demonstrate a single longitudinal mode and single polarization laser output that can stabilize robustly at 500 ?.The results reveal that the proposed grating qualifies as a high-quality in-fiber bandpass filter with high-temperature resistance,providing a device foundation for the generation,transmission,and acquisition of fiber signals in extreme environments.Second,we propose and implement a new-type superstructure phase-shifted fiber Bragg grating.Investigating its temperature characteristics,we reveal,for the first time,the temperature memory effect of the fiber Bragg grating.The grating can memorize the information of highest ambient temperature,up to 500 ?,within a certain period of time,through its dual-resonance structure..Notably,the memory effect is immune to the cross-sensitivity.Subsequently,the impact of negative refractive index component on this memory effect is proposed and preliminarily verified.Eventually,taking advantage of the rapid response characteristics of its temperature memory function,we demonstrate the application of this grating in one-dimensional data storage.The results manifest that this grating has great application potential in the fields of energy source,geological prospecting and data storage.