| Recently, there has been renewed interest in fiber taper due to its potential to be a building block for micro and nano photonic devices with unique optical and mechanical properties. This thesis is concerned with the study of two key applications which are optical filtering and sensing. Since the exploding demand of broadband optical communications system, the incorporation of fiber taper as a tunable filter in Brillouin-erbium fiber laser further extends the tunability and number of lasing wavelength in the multi-wavelength laser. Apart from that, it serves as sensor to monitor and inspect the structural health of civil infrastructure.;A new method of tuning a multi-wavelength fiber laser by incorporating fiber taper is experimentally demonstrated. As a tunable filter, the biconical fiber taper and in-line two tapers interferometer are incorporated into the Brillouin-erbium doped fiber laser system to position the self-lasing cavity modes. Subsequently, by injecting the Brillouin pump near to the tunable self-lasing cavity modes, it suppresses the modes and generates stable cascaded Brillouin-stokes lines. Interestingly, not only wavelength shifting, the bandwidth of the self-lasing cavity mode is tunable by compressing the in-line two tapers MZI. Therefore, the number fo lasing wavelength is switchable to the maximum number of 12 while maintaining the extinction ratio of 20 dB. |
