Optical pulse generator using gain-switched semiconductor laser

An optical pulse generator for generating ultrashort optical pulses comprising:

• a semiconductor laser having a resonant cavity containing at least an active layer, a cladding layer and two pair of electrodes, wherein said resonant cavity includes a current injection region having one pair of said two pair of electrodes for injecting current into said active layer and a current non-injection region having said other pair of electrodes for applying a reverse bias voltage to said active layer, wherein said current injection region and said current non-injection region are electrically isolated from each other;
• a pulse current source for injecting pulse current into said current injection region for generating laser light;
• a voltage source for applying a reverse bias voltage to said current non-injection region for controlling the absorption coefficient of laser light;
• and
• a wavelength conversion element comprising an optical waveguide which is disposed in a surface portion of said wavelength conversion element;
• wherein said optical waveguide is aligned so as to generate a second harmonic wave of a fundamental wave from said optical waveguide, when the fundamental wave is coupled to said optical waveguide and is guided by said optical waveguide;
• whereby a gain in said current injection region increases and an absorption in said current non-injection region decreases in a gain-switching manner so as to generate ultrashort optical pulses and whereby said ultrashort optical pulse guided in said optical waveguide serves as a fundamental wave for said wavelength conversion element;
• and
• whereby ultrashort optical pulses consisting of the second harmonic wave of the fundamental wave are outputted from said optical waveguide.