2-μm numerical analysis of linear-cavity FP structures based on fiber Bragg gratings.

The linewidth performance of all-fiber, linear-cavity Fabry–Perot structures based on fiber Bragg gratings operating at 2-μm band has been investigated numerically. The output linewidth performance of two symmetrical and asymmetrical cavities has been theoretically studied and comprehensively compared. The numerical analysis is based on the transmission matrix method with the simplified parameters. The simulation results show that cavity lengths, cavity lengths ratio, grating lengths, grating lengths ratio, as well as index modulation depths, affect the output linewidth performance. The tolerance ability of the asymmetrical structure is first proposed and investigated under 1 mm accuracy, and single-frequency output can be realized by properly adjusting the properties of the proposed composite linear cavity structure. [ABSTRACT FROM AUTHOR]