公开(公告)号：JPH04240787A

公开(公告)日：1992-08-28

申请号：JP4457491

申请日：1991-01-17

Applicant: IBM

Inventor： AMANO YOSHIRO ,  SOTOZONO KAZUO ,  SHIMOUSA TATSUO

IPC: G11B7/125 ,  G11B7/126 ,  H01S5/042

Abstract: PURPOSE: To obtain a laser drive device for increasing a switching speed easily, by providing both flow-out and flow-in constant current sources and a switching means for turning laser on or off. CONSTITUTION: A write data signal Sd and its inverted signal -Sd are inputted to the bases of transistors(Tr) 41A and 41B of a switch circuit 40. When the Tr41A is turned on and the Tr41B is turned off, a switch current Isa that flows through the Tr41A becomes equal to the flow-in current Ib of a flow-in constant current source 20, and a switch current Iab that flows through the Tr41B becomes zero. As a result, a laser current I1 becomes equal to an flow-out current Ia of a flow-out constant current source 30, thus turning on a laser 50. On the other hand, when the Tr41A is turned off and the Tr41B is turned on, the switch current Isa becomes zero and the switch current Isb becomes equal to the flow-in current Ib and the flow-out current Ia , thus setting the laser current I1 to zero and turning off the laser 50.