A wavelength tunable mode-locked laser system including a complex laser cavity
comprising a broadband reflective mirror at one end and a wavelength chirped selective
mirror at the other end. The system further includes a gain element and a low finesse
Fabry-Perot etalon element inside the laser cavity. The gain element may be a semiconductor
laser chip, with a broadband high reflection coating at one end and a partially
reflecting coating at its other end. The gain element has a well-defined length,
such that its longitudinal modes match a required optical frequency grid. The system
also includes an active modulation element applied externally on said complex laser
cavity to provide mode-locking of a specific cavity length among said defined predetermined
cavity lengths, such that all possible optical frequencies emitted by the laser
system are stabilized to the linear grid dictated by the Fabry-Perot longitudinal
modes, that could be in accordance with the International Telecommunications Union Standards.