Widely tunable and switchable multiwavelength erbium-doped fiber laser based on a single ring cavity

In this paper, we propose and demonstrate through numerical simulations a novel, to the best of our knowledge, widely tunable and switchable multiwavelength erbium-doped fiber laser (EDFL) operating in the 1524-1650 nm wavelength range covering the C-, L-, and U-bands. The EDFL is based on a single ring cavity and a single forward pump source operating at 980 nm wavelength. The length of the erbium-doped fiber and pumping configuration is optimized, enabling a wide tuning of 126 nm with an average lasing power of 15 dBm. Switchable multiple wavelengths are generated from the EDFL through an intracavity tunable optical filter (TOF) and a specially designed out-of-cavity comb filter (CF). Forty-nine wavelengths having average optical power and linewidth of around −10 dBm and 0.01 nm, respectively, are obtained at the output of the CF. Moreover, the free spectral range among the multiple wavelengths is adjusted easily by simply varying the frequency of sinusoidal radio frequency signal used to modulate the lasing signal obtained by tuning the intracavity TOF at a particular wavelength with the help of a dual-drive Mach-Zehnder modulator. The proposed EDFL is low cost, efficient, and highly stable with an average output power of around 15 dBm for 10% output coupling ratio over a 126 nm wide tuning range covering C-, L- and U-bands.