Patent ID: 8014428

Claim:
A mode-locked laser for generating laser pulses, the mode-locked laser comprising: an optical coupler; a first optical path capable of carrying optical signals from and to the optical coupler, the first optical path including an optical amplifier that is arranged so that saturation of optical amplification causes amplitude modulation of light, the optical amplifier having a saturation time that is shorter than a pulse transition period of the mode-locked laser and being arranged for recovery of amplifying properties after the saturation within a period of time that is shorter than the pulse transition period of the mode-locked laser; and a second optical path capable of carrying optical signals from and to the optical coupler, the second optical path including an optical isolator; wherein the first optical path has a non-linear property and is arranged so that, when a light pulse that is received from the second optical path is split by the optical coupler into component light pulses that are directed in opposite directions in the first optical path, the component light pulses experience differing shifts in phase and wherein the mode-locked laser is arranged so that mode-locked lasing is initiated by a light pulse that is amplitude modulated by the optical amplifier.