A tuneable ring laser having a ring cavity, wherein the ring cavity comprises at least one ring resonator having a waveguide for guiding waves, a phase modulator having a waveguide for guiding waves, one or more power couplers for coupling the waves in, and out of, the at least one ring resonator, wherein a cross section of the waveguides of the at least one ring resonator and the phase modulator is configured as PIN diodes and act as an electro-refractive modulator such that the tuneable ring laser is tuneable by applying a reverse bias voltage.

In a first embodiment, an external cavity tunable laser, comprising a silicon photonics circuit comprising one or more resonators having one or more p-i-n junctions; wherein a voltage is applied to one or more of the p-i-n junctions. In a second embodiment, a method of operating an external cavity tunable laser, comprising sweeping out free-carriers from a resonator of the tunable laser by applying a voltage to a p-i-n junction of a waveguide of the resonator.

In a first embodiment, an external cavity tunable laser, comprising a silicon photonics circuit comprising one or more resonators having one or more p-i-n junctions; wherein a voltage is applied to one or more of the p-i-n junctions. In a second embodiment, a method of operating an external cavity tunable laser, comprising sweeping out free-carriers from a resonator of the tunable laser by applying a voltage to a p-i-n junction of a waveguide of the resonator.

A laser device according to the present invention may comprise: a pumping laser supply unit for emitting a pumping laser having a nano-second pulse width; and a laser output unit disposed at one side of the pumping laser supply unit and generating an output laser which is pumped by the pumping laser to have a nano-second pulse width corresponding to the pulse width of the pumping laser.

A laser device according to the present invention may comprise: a pumping laser supply unit for emitting a pumping laser having a nano-second pulse width; and a laser output unit disposed at one side of the pumping laser supply unit and generating an output laser which is pumped by the pumping laser to have a nano-second pulse width corresponding to the pulse width of the pumping laser.