PURPOSE: To set and reset a semiconductor laser by emitting two types of specific external input lights to the laser, and controlling optical bistable characteristic in the output light properties of the laser to the intensity of the first external input light according to the intensity of the second external input light.
CONSTITUTION: An external input light 1 (optical intensity X1) having a wavelength λ1 (frequency f1) and an external input light 2 (optical intensity X2) having a wavelength λ2 (frequency f2) are incident to a semiconductor laser 3 to be oscillated with a wavelength λ0 (frequency f0), and output lights 4-6 (optical intensities (Y0-Y2) corresponding to the wavelengths l0, λ1 and l0 are obtained as output lights. Here, (f0-f1)<(f0-f2) is satisfied. That is, lights having a longer wavelength than the oscillation wavelength of the laser and different two wavelengths l1, l2 are simultaneously emitted to the laser 3 to control bistability in the light input/output characteristics of the laser. Thus, an optical memory function, a flip-flop operation, etc., can be realized without using a semiconductor laser of a specific structure.
TAKIZAWA KUNIHARU
KIKUCHI HIROSHI
FUJIKAKE HIDEO
