| 摘要 |
PURPOSE:To simplify a switching unit by switching a fixed current source which outputs a predetermined current value capable of flashing an arbitrary semiconductor laser by the switching unit composed of an emitter-grounded transistor circuit. CONSTITUTION:A switching element 31 which switches a fixed current source 11 by supplying a driving current Id to the active region of a laser element 1a is provided. The element 31 is set to an OFF state while a variable current source 21 is held in a controlling state by determining a bias current Ib of a forward current If by feeding back when the element 31 is ON, thereby stopping the supply of the current Id of the current If. Thus, since only the current Ib is supplied to a laser element 1a, it is deenergized. Then, the element 31 is again returned to the ON state to supply both the currents Ib and Id to the element 1a, and it is reenergized. Thus, transistors which perform switching functions can be reduced. |
