JPS6286565U

JPS6286565U -

Info

Publication number: JPS6286565U
Application number: JP17836285U
Authority: JP
Priority date: 1985-11-19
Filing date: 1985-11-19
Publication date: 1987-06-02

Description

[Brief explanation of the drawing]

第１図は本考案の一実施例の概略構成ブロツク
図、第２図は従来例の概略構成ブロツク図、第３
図〜第５図はｄＬ／ｄＩ特性の波形図である。３……レーザダイオード、４……ホトダイオー
ド、１０……交流電源、２０……定電流回路、２
１……Ｄ／Ａ変換器、２２……Ｖ／Ｉ変換器、３
０……交流成分出力回路、３１……ロツクイン増
幅器、３２……Ａ／Ｄ変換器、４０……メモリ回
路、５０……制御部。 Fig. 1 is a schematic block diagram of an embodiment of the present invention, Fig. 2 is a schematic block diagram of a conventional example, and Fig. 3 is a schematic block diagram of a conventional example.
5 to 5 are waveform diagrams of dL/dI characteristics. 3... Laser diode, 4... Photodiode, 10... AC power supply, 20... Constant current circuit, 2
1...D/A converter, 22...V/I converter, 3
0...AC component output circuit, 31...Lock-in amplifier, 32...A/D converter, 40...Memory circuit, 50...Control unit.

Claims

[Claims for Utility Model Registration] Differential characteristics of optical output with respect to driving current (differential L-I characteristics) when an AC voltage is applied to a laser diode.
In the circuit for measuring the drive current, there is a constant current circuit that changes the digital voltage of the staircase wave by D/A to make a constant current, and a constant current circuit that extracts the alternating current component in the optical output photoelectrically converted by the photodiode and converts it to A/A. an AC component output circuit that performs D conversion;
It has a memory circuit that stores the digital output, and a control unit that supplies the staircase wave digital voltage and controls the various circuits, and the control unit sequentially reads out the output from the memory circuit, integrates it, and , a differential L-I waveform determination device for a laser diode, characterized in that it has arithmetic means for emphasizing the dip in the differential LI characteristic by subtracting from the output.