PURPOSE: To convert intensity-modulated light into another intensity-modulated light having another wavelength and the same pattern by providing a laterally injected waveguide crossing a saturable absorption waveguide, reflectivity adjusting layers on the end face of a distributed feedback laser, and another reflectivity adjusting layer on the end face of a second gain waveguide.
CONSTITUTION: As the voltage applied across a saturable absorption waveguide 104 is dropped, the light loss in the waveguide 103 increases and, at the same time, the light returning to a distributed feedback laser 102 from the side face of the waveguide 104 on a second gain waveguide 105 side decreases. Because of the two effects, the optical output from the side face of the waveguide 104 on the waveguide 105 side decreases. When the currents injected to the laser 102, gain waveguides 103 and 104, and a laterally injected waveguide 106 are respectively controlled to 80mA, 30mA, and 100mA and the voltage applied across the waveguide 104 is controlled to -1.0V, light is made incident to the waveguide 106. The intensity of outgoing light from a laser 102 can be modulated based on the relation between the intensity of incident light and optional output.
NONAKA KOJI
KUROKAWA TAKASHI
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