| A fiber ring laser, using erbium-ytterbium co-doped double clad fiber is proposed and demonstrated to produce a medium power multiwavelength fiber laser. The experimental results show that the ring resonator configuration can produce more output power compared to a laser based on bidirectional pumping scheme in Fabry-Perot resonator configuration. To stabilize the lasing lines we used an unpumped erbium doped fiber as saturable absorber. A sagnac loop interferometer is used as a filter inside the cavity and its effect has been explored. We can produce a maximum four lasing lines which are stable for more than 2 hours when observed through OSA with a resolution of 0.05 nm. The maximum output power obtained from the laser is more than 100 mW. Our best result at room temperature is simultaneous oscillations of two single-mode laser wavelengths with a maximum output power of 60 mW when observed through a scanning Fabry-Perot spectrum analyzer of resolution 27 MHz. |
