All-optical modulation of Fano-like resonances in apodized fiber Bragg grating using Er/Yb doped fiber

Abstract

A novel all-optical scheme for fast modulation of Fano-like resonance using Er/Yb doped fiber (EYDF) is proposed and demonstrated experimentally. In the integrated system, an apodized fiber Bragg grating (AFBG) is inserted into one arm of the fiber Mach-Zehnder interferometer (MZI), and the asymmetric Fano-like resonances is generated by the interference between the MZI mode and AFBG mode. In addition, a section of EYDF is inserted into the other arm of the MZI to control the phase difference between the two arms of the MZI. By adjusting the power of optical pump applied to the EYDF, the transmission spectrum lineshapes of the integrated device can be effectively modulated into asymmetric Fano-like resonances, symmetric transmission dip or electromagnetically induced transparency (EIT)-like resonances, which has a fast response speed. The proposed all-optical Fano-like modulation scheme is simple in structure, and has advantages of remote control and long-term stability, providing potential applications in the fields of fast and slow light, optical filters and fiber sensing.

Influence of light source modulation on detection performance of trace-level SF6 fault gas using photoacoustic spectroscopy

“…In this study, a cylindrical single-pass PAS was used to investigate the effects of light source modulation methods on the performance of PAS gas detection system. We initially analyze The mechanisms of square wave signal-based intensity modulation and sawtooth wave signal superimposed with sinusoidal signal-based second harmonic wavelength modulation were analyzed [20][21][22], and the harmonic component order were established, following by using H 2 S as the target gas. The PAS experiments was conducted under these modulation methods, comparing the PA signal amplitudes under multiple conditions (modulation frequency and PC length), thereby analyzing the suitability of modulation methods for different experimental conditions and application scenarios.…”