Patent ID: 8442079

Claim:
A method of driving a semiconductor laser device comprising: (a) a laminated structure in which a first compound semiconductor layer having a first conductive type and composed of a GaN base compound semiconductor, a third compound semiconductor layer having an emission region and a saturable absorption region composed of the GaN base compound semiconductor, and a second compound semiconductor layer having a second conductive that is different from the first conductive type and composed of the GaN base compound semiconductor are successively laminated; (b) a second electrode formed on the second compound semiconductor layer; and (c) a first electrode electrically connected to the first compound semiconductor layer, wherein the laminated structure is formed on a compound semiconductor substrate having polarity, the third compound semiconductor layer includes a quantum well structure having a well layer and a barrier layer, the well layer has a depth of 1 nm or more and 10 nm or less, the barrier layer has an impurity doping density of 2×10 18 cm −3 or more and 1×10 20 cm −3 or less, and generating an optical pulse in the emission region by passing a current from the second electrode to the first electrode via the laminated structure, and wherein the second electrode is separated into at least a first portion and a second portion by a separation groove, and a value of electric resistance between the first portion and the second portion of the second electrode is 1×10 2 Ω or more.