JPS5687389A - Protection of semiconductor laser - Google Patents

Protection of semiconductor laser

Info

Publication number
JPS5687389A
JPS5687389A JP16428479A JP16428479A JPS5687389A JP S5687389 A JPS5687389 A JP S5687389A JP 16428479 A JP16428479 A JP 16428479A JP 16428479 A JP16428479 A JP 16428479A JP S5687389 A JPS5687389 A JP S5687389A
Authority
JP
Japan
Prior art keywords
temperature
output
semiconductor laser
comparator
signal generator
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
JP16428479A
Other languages
Japanese (ja)
Inventor
Isamu Shibata
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.)
Ricoh Co Ltd
Original Assignee
Ricoh Co 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 Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP16428479A priority Critical patent/JPS5687389A/en
Publication of JPS5687389A publication Critical patent/JPS5687389A/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
    • H01S5/06825—Protecting the laser, e.g. during switch-on/off, detection of malfunctioning or degradation

Landscapes

  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Semiconductor Lasers (AREA)

Abstract

PURPOSE:To prevent an increase in the excessive injection current of a semiconductor laser element or the like by protecting the element against the flow of current until the temperature of the element reaches a predetermined temperature. CONSTITUTION:The temperature of a semiconductor laser element 22 is detected by a thermistor 21 and the temperature is compared with an output in a standard signal generator 25 by a comparator 24 to maintain the temperature of the element 22 at a previously set temperature by driving a temperature control element 26 by the difference. The output in the comparator 24 is positively coded by an absolute value circuit 27 and compared with the output in a standard signal generator 29 by a comparator 28. And the element 22 is driven by a fixed injection current by operating a DC power source 30 when the output in the absolute value circuit 27 becomes lower than that in the standard signal generator 29 or when the temperature of the element 22 reaches in the range of a predetermined temperature with a set temperature as the central figure.
JP16428479A 1979-12-18 1979-12-18 Protection of semiconductor laser Pending JPS5687389A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP16428479A JPS5687389A (en) 1979-12-18 1979-12-18 Protection of semiconductor laser

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP16428479A JPS5687389A (en) 1979-12-18 1979-12-18 Protection of semiconductor laser

Publications (1)

Publication Number Publication Date
JPS5687389A true JPS5687389A (en) 1981-07-15

Family

ID=15790168

Family Applications (1)

Application Number Title Priority Date Filing Date
JP16428479A Pending JPS5687389A (en) 1979-12-18 1979-12-18 Protection of semiconductor laser

Country Status (1)

Country Link
JP (1) JPS5687389A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58182286A (en) * 1982-04-16 1983-10-25 Sanyo Electric Co Ltd Semiconductor laser element drive circuit
JPH02244685A (en) * 1989-03-15 1990-09-28 Nec Corp Ld module protecting method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58182286A (en) * 1982-04-16 1983-10-25 Sanyo Electric Co Ltd Semiconductor laser element drive circuit
JPH02244685A (en) * 1989-03-15 1990-09-28 Nec Corp Ld module protecting method

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