SEMICONDUCTOR LASER DEVICE

PURPOSE:To obtain a single mode oscillation having low oscillation threshold current and high stability forming an N type or P type or non-conductive region of a depth reaching an active region in contact with an end face of a resonator. CONSTITUTION:It is assumed that the right sides of P type regions 8 and 9 are N type regions. A P type or I type region 12 is formed in a depth deeper than that reaching an active layer 3 in contact with the end face 10 of a resonator in the N type region, but is not contacted with the region 9, is formed as near as possible in a length to be superposed with the crank-shaped bent part 11 in an end face direction vertical to the direction of the resonator. When a voltage is applied to both P type and N type electrodes in this manner, a most current flow only to the P-N juntion parallel to the direction of the resonator, and does not accordingly flow through the P-N junction parallel to the end face bent at the crank. Accordingly, a reactive current can be eliminated, with the result that the laser of low threshold current can be obtained.