JPS6250998B

PURPOSE:To enable to vary the oscillating wavelength with one element by altering the period of diffraction lattice in one direction in a distributed feedback type structure and providing a plurality of electrodes in the altering direction. CONSTITUTION:In a semiconductor laser, 7-1-7-10 are positive electrodes, broken lines indicate the direction of grooves of diffraction grating 5 in the crystal. The period of the grating is constant in y direction and continuously variable in x direction. The light output is cleaved in the crystal at one end of the electrode, and produced therefrom. In such a structure, when the adjacent two positive electrodes are simultaneously driven by the currents at the suitable rate, an oscillation can be obtained at the intermediate value of the wavelengths corresponding to the respective electrodes. Further, a plurality of positive electrodes which are not adjacent are simultaneously driven to simultaneously obtain the oscillating wavelengths corresponding to the electrodes. In this manner, one element can readily produce an oscillation with arbitrary wavelength in the gain spectrum of the active substance.