Title:
【発明の名称】レーザダイオードの制御方式
Document Type and Number:
Japanese Patent JP2550447
Kind Code:
B2
Abstract:
A laser diode (10) in which a cathode is connected to the ground side of a positive power source and an anode is connected to the plus voltage side of the positive power source through a control circuit and whose light emission is driven such that its light-emission is controlled. A maximum current to drive the laser diode (10), for instance, a write current (Iw) is supplied to the laser diode by a disgorging type constant current source (12-1). In the reading mode, a differential current between the write current (Iw) and a read current (Ir) is sucked from the disgorging type constant current source (12-1) by a sucking type constant current source (12-2), thereby allowing the read current (Ir) to flow into the laser diode (10). In the writing mode, a current switch (14-1) is connected to the sucking type constant current source (12-2) of the differential current and is switched in accordance with write data. Further, in a manner similar to the laser diode side, the disgorging type constant current source (12-1) and the sucking type constant current source (12-2) are also connected through a current switch (14-4) to a photodiode (22) to monitor a light emission amount in a unit of the laser diode (10). An APC is made operative by a monitor light corresponding to a read power, thereby reducing a fluctuation of a light amount due to a temperature or a time-dependent change. In the reading mode, a modulation is executed at a frequency which is one or more digit higher than a frequency for the write data, thereby reducing influences by noises of the laser diode or backtalk noises.
Inventors:
MINAMI AKIRA
TANAKA SHIGEYOSHI
TANAKA SHIGEYOSHI
Application Number:
JP11148691A
Publication Date:
November 06, 1996
Filing Date:
May 16, 1991
Export Citation:
Assignee:
FUJITSU LTD
International Classes:
G11B7/00; G11B7/0045; G11B7/005; G11B7/125; G11B7/126; H01S5/042; (IPC1-7): G11B7/125; G11B7/00; H01S3/096
Domestic Patent References:
| JP4157632A | ||||
| JP4240787A |
Other References:
【文献】特開平-220144(JP,A)
Attorney, Agent or Firm:
Susumu Takeuchi (1 person outside)