Fig. 1. Schematic of MSL filter

Fig. 2. Transmission spectrum of MSL filter obtained by simulation and experiment

Fig. 3. Schematic of experimental setup for fused tapering by oxyhydrogen flame

Fig. 4. The experimental setup of switchable erbium-doped fiber laser

Fig. 5. Output spectra of single wavelength

Fig. 6. Output spectra of single wavelength matched with MSL spectrum

Fig. 7. Output spectra of double wavelength

Fig. 8. Output spectra of triple wavelength

Fig. 9. Output spectra of quadruple wavelength

Fig. 10. Measurement of laser stability

Fig. 11. Measurement of laser stability after adding an isolator

Fig. 12. Measured laser output versus pump power