1. A broadband discrete spectrum optical source comprising: a gain medium having a wavelength dependent gain spectrum, a feedback cavity including at least two reflectors, wherein reflectivity of at least a first reflector is higher at wavelengths corresponding to the band edges than at mid-band of said gain spectrum, and wherein the reflectivity of the first reflector is substantially higher than the reflectivity of a second reflector; and the gain medium is disposed within the feedback cavity such that a light generated by adjusting the gain of the gain medium undergoes multiple reflections thereby, generating an output light having discrete emission lines with high output power over a bandwidth extended beyond the band edges of said gain spectrum.