Abstract: A photonic integrated circuit device includes a lasing cavity for resonating at a plurality of discrete wavelengths and an optical feedback cavity operably coupled to the lasing cavity via a front surface of the lasing cavity. The optical feedback cavity has a reflective element for reflecting light, at least partially, back into the lasing cavity to form a resonant Fabry-Perot cavity between the front surface and the reflective element. The optical feedback cavity includes a variable phase shifting element adapted for receiving an input signal to control a phase shift of light propagating in the optical feedback cavity. The amount of light entering the lasing cavity from the optical feedback cavity is low enough to avoid dynamic instability of the lasing cavity. The reduction in light is obtained using an attenuator.