Abstract: A photonic integrated circuit-based dual frequency comb source, an integrated system for dual comb spectroscopy and corresponding method are disclosed. The dual comb source includes, on a same substrate of the photonic integrated circuit, a first and second semiconductor integrated mode-locked laser, a master laser, and connection arrangement between the master laser and each of the first and second mode-locked laser. The master laser is configured for generating a lasing line for simultaneous optical injection-locking of the first and second mode-locked laser, the first and second mode-locked laser are configured for generating a first and second frequency comb respectively, and the connection arrangement is suitable for coherently transferring lasing light from the master laser to each mode-locked laser. The mode-locked lasers include a gain section and a saturable absorber section to provide mode-locking, and an extended optical cavity formed in the substrate.