JPS55110086A - Light output cut-off detecting system - Google Patents

Light output cut-off detecting system

Info

Publication number
JPS55110086A
JPS55110086A JP1600379A JP1600379A JPS55110086A JP S55110086 A JPS55110086 A JP S55110086A JP 1600379 A JP1600379 A JP 1600379A JP 1600379 A JP1600379 A JP 1600379A JP S55110086 A JPS55110086 A JP S55110086A
Authority
JP
Japan
Prior art keywords
circuit
current
emitting element
light emitting
reference value
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP1600379A
Other languages
Japanese (ja)
Inventor
Masakazu Mori
Sadao Ifukuro
Yasuo Nagai
Toshiyuki Yamashita
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujitsu Ltd
Original Assignee
Fujitsu Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP1600379A priority Critical patent/JPS55110086A/en
Publication of JPS55110086A publication Critical patent/JPS55110086A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
    • H01S5/068—Stabilisation of laser output parameters
    • H01S5/0683—Stabilisation of laser output parameters by monitoring the optical output parameters
    • H01S5/06832—Stabilising during amplitude modulation

Landscapes

  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Semiconductor Lasers (AREA)
  • Led Devices (AREA)
  • Dc Digital Transmission (AREA)
  • Optical Communication System (AREA)

Abstract

PURPOSE:To detect a light output cut stably and accurately with respect to the light signal mark rate variation by a simple and low-cost structure. CONSTITUTION:In comparing the light output from a light emitting element with the refernce value, the reference value is not set at a fixed voltage but it is made variable corresponding to the drive voltage or the drive current of the light emitting element. To a conventional detector circuit are added newly current switching circuit 21, including a pair of transistors Q3, Q4, DC amplifier 22 and CR circuit 23. A reference value to be fed to comparator circuit 15 is formed by means of these circuits. Circuit 21 is of the same structure as circuit 12 and it takes out from Q4 a current which is exactly equivalent to the drive current to be fed to light emitting element 11 via Q2. The variation in this equivalent current is DC amplified (22), its average value is taken by circuit 23, and it is made as a variable reference value. CR circuit 14 is provided corresponding to circuit 23. When one of poor frequency response characteristics is used for monitoring light receiving element 13, circuit 14 is not needed, and the output of element 13 shows the average value. At this time, the time constant of circuit 23 is adjusted at about 100kHz. By this structure, erroneous judgment can be eliminated.
JP1600379A 1979-02-16 1979-02-16 Light output cut-off detecting system Pending JPS55110086A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1600379A JPS55110086A (en) 1979-02-16 1979-02-16 Light output cut-off detecting system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1600379A JPS55110086A (en) 1979-02-16 1979-02-16 Light output cut-off detecting system

Publications (1)

Publication Number Publication Date
JPS55110086A true JPS55110086A (en) 1980-08-25

Family

ID=11904432

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1600379A Pending JPS55110086A (en) 1979-02-16 1979-02-16 Light output cut-off detecting system

Country Status (1)

Country Link
JP (1) JPS55110086A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5769228A (en) * 1980-10-18 1982-04-27 Fuji Electric Co Ltd Deterioration detection system for optical transmitting circuit
JPS5860843A (en) * 1981-10-06 1983-04-11 Natl Aerospace Lab Fault judging circuit
JPS59239A (en) * 1982-06-25 1984-01-05 Nec Corp Pulse code modulation signal cut-off detecting circuit

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5769228A (en) * 1980-10-18 1982-04-27 Fuji Electric Co Ltd Deterioration detection system for optical transmitting circuit
JPS6351424B2 (en) * 1980-10-18 1988-10-13 Fuji Denki Kk
JPS5860843A (en) * 1981-10-06 1983-04-11 Natl Aerospace Lab Fault judging circuit
JPS59239A (en) * 1982-06-25 1984-01-05 Nec Corp Pulse code modulation signal cut-off detecting circuit

Similar Documents

Publication Publication Date Title
JPS6410704A (en) High frequency detecting circuit
JPS55110086A (en) Light output cut-off detecting system
JPS559143A (en) Temperature detector
JPS51127774A (en) Temperature compensation circuit for radiant ray detector
JPS5698913A (en) Temperature control circuit for amplifier
GB1261735A (en) Feedback amplifier arrangements
JPS5552605A (en) Detector circuit
ES459130A1 (en) Receiver for a HF-intrusion detection system
JPS5551349A (en) Sodium ionization detector
JPS5773429A (en) Parallel operation system of switching power supply
JPS55138665A (en) Detecting system of operation fault of heating source
JPS5471503A (en) Monitor system of photo reception level
SU485368A1 (en) Radiometric flaw detector
JPS5432925A (en) Signal processing circuit
JPS55162069A (en) Fault detector for electric temperature detector
JPS5466894A (en) Banknote color detecting apparauts
KR920007127Y1 (en) Dropout detecting circuit
JPS5765968A (en) Drop-out detecting circuit
JPS51145381A (en) Temperature detecting circuit
JPS54131981A (en) Automatic control circuit of photo detecting sensitivity
JPS6442904A (en) High frequency power monitor
JPS5672509A (en) Dc gain control device
JPS54101277A (en) Prober for semiconductor wafer
JPS5451492A (en) Output stabilizing system for semiconductor laser
JPS55150019A (en) Automatic control circuit for optical output