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Laser diode driving circuit

A technology of laser diodes and driving circuits, applied in circuits, lasers, laser components, etc., can solve the problems of low ground terminal b impedance, inability to completely remove noise, etc., to prevent amplitude changes, reliably remove noise, and reduce current output Effect

Inactive Publication Date: 2009-08-26
SUMITOMO ELECTRIC IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At this time, the filter circuit 10 was originally intended to remove noise, but the noise flowing through the laser diode driver IC may not be completely removed due to the low impedance of the ground terminal b of the laser diode driver IC.

Method used

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  • Laser diode driving circuit
  • Laser diode driving circuit
  • Laser diode driving circuit

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Experimental program
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Embodiment Construction

[0025] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0026] figure 1 It is a circuit diagram showing a laser diode (hereinafter referred to as "LD") driving circuit 1 of the present invention.

[0027] The LD drive circuit 1 includes: an amplifying circuit composed of two transistors FET1 and FET2; a third transistor FET3 controlling the pulse modulation amplitude; a fourth transistor FET4 setting the LD bias current; resistors R and R inserted into the load of the amplifying circuit respectively. LD; and a filter circuit 2 commonly connected to said resistors R and LD.

[0028] The path P1 from the power supply, LD, and the first transistor FET1 to the ground is called the first current path P1, and the path P2 from the power supply, the resistor R, and the second transistor FET2 to the ground is called the second current path P2.

[0029] A burst signal for high-speed on-off control of the LD from a signal ...

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PUM

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Abstract

PROBLEM TO BE SOLVED: To provide a driving circuit of a laser diode capable of surely eliminating noise without adversely affecting the current amplifying action of the driving circuit of the laser diode. SOLUTION: The driving circuit of the laser diode is provided with a first current route P1 from a power source, the laser diode LD, and a first transistor FET1 to the ground; and a second current route P2 from the power source, a resistor R, and a second transistor FET2 to the ground. To the FET1 and the FET 2, the input signals of phases opposite to each other for respectively controlling currents flowing through the current routes P1 and P2 are supplied. A filter circuit 2 is inserted between the power source and a common contact (a) of the laser diode LD and the resistor R.

Description

technical field [0001] The present invention relates to a laser diode drive circuit applied to an optical transmission device using a semiconductor laser (referred to as a laser diode). Background technique [0002] In recent years, the speed of optical communication has been increased, and with this increase, the speed of the pulse signal composed of 0 and 1 digital signals for communication purposes supplied to the laser diode drive circuit has also been increased. Specifically, the 0, 1 digital signal bit interval of the pulse signal is shortened to about 1 to 10 nanoseconds. The laser diode drive circuit converts the electrical amplitude of the pulse signal into the strength of the laser diode drive current. When there is noise in the driving current of the laser diode driving circuit, which disturbs the optical signal waveform, a filter circuit for removing noise must be added to the current path. [0003] In the prior art, when removing the noise of the laser diode d...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01S5/042H01S5/06
CPCH01S5/0427H01S5/06203H01S5/06817
Inventor 川西康之
Owner SUMITOMO ELECTRIC IND LTD