Volume Bragg Grating-Based Tunable Er,Yb Fiber Lasers Covering the Whole C- and L-Band

High power and widely wavelength tunable operation of cladding-pumped Er,Yb fiber lasers are demonstrated with operating wavelength covering the whole C- and L-band and spectral linewidth FWHM of less than ~0.3 nm over the whole tuning range. Wavelength tuning is realized by the use of an external cavity containing a volume Bragg grating with peak reflectivity 99% at 1650 nm. A tuning range of 45.5 nm from 1533.5 to 1579 nm is obtained for a 7 m Er,Yb fiber. Output power up to 23.8 W is generated at 1565.7 nm for 142.4 W of launched pump power. Using a longer gain fiber of 17 m, the operating wavelength shifted toward the long wavelength side, covering a tuning range of over 67 nm from 1556.7 to 1624.4 nm. A maximum output power of 24.9 W at 1567.5 nm is achieved for the launched pump power of 126.5 W.