| 摘要 |
PURPOSE:To shorten an aging time largely, and to simplify screen by changing radio waves applied to a semiconductor laser, obtaining a current value, in which an optical output from a laser reaches the maximum of a secondary difference section by currents, and using the current value as the oscillating threshold currents of the laser. CONSTITUTION:An optical output L from a laser is measured while varying currents I applied to a semiconductor laser, and a current I-optical-output L characteristic curve 3 shown in the graph is obtained. A secondary difference section curve 10 by currents I by the curve 3 is acquired, a current value (b) at a point 11 representing the maximum value in the curve 10 is obtained, and the current value (b) is employed as oscillating threshold currents Ith. Consequently, oscillating threshold currents Ith can be settled at one value to one semiconductor laser. Accordingly, oscillating threshold currents can be fixed at a physical significant one value to one semiconductor laser, thus making an aging time in screening largely shorter than conventional devices, then simplifying screening. |
