GB1363029A - Method of and an arrangement for modulating directly a semiconductor laser - Google Patents

Method of and an arrangement for modulating directly a semiconductor laser

Info

Publication number
GB1363029A
GB1363029A GB4653272A GB4653272A GB1363029A GB 1363029 A GB1363029 A GB 1363029A GB 4653272 A GB4653272 A GB 4653272A GB 4653272 A GB4653272 A GB 4653272A GB 1363029 A GB1363029 A GB 1363029A
Authority
GB
United Kingdom
Prior art keywords
mode
output beam
optical
modes
peaks
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.)
Expired
Application number
GB4653272A
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.)
Hitachi Ltd
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Publication of GB1363029A publication Critical patent/GB1363029A/en
Expired 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
    • H01S5/062—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes
    • H01S5/06209—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in single-section lasers
    • H01S5/06213—Amplitude modulation

Landscapes

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

Abstract

1363029 Lasers HITACHI Ltd 9 Oct 1972 [8 Oct 1971] 46532/72 Heading H1C A semi-conductor laser modulator has its bias current adjusted to a value producing an output beam with a particular TE mode, and a modulating current of a selected value is superposed on the bias current so as to cause the output beam to change to a different TE mode, the output beam being applied through an optical path capable of transmitting one only of the modes. A stripe electrode semi-conductor is used which is either a GaAs PN junction, Fig. 1 (not shown), or a GaAs-GaApAs double heterostructure, Fig. 2a (not shown). Two of the modes TE 00 , TE 01 , TE 02 are preferably used, Fig. 1b the intensities shown being across the beam emitting region of the semiconductor face. Mode selection in the optical path may be effected by a pair of optical fibres 22, 24, Fig. 3b, aligned with the beam emitting region of the semi-conductor face so as to pass the two peaks, respectively, of a TE o1 mode beam 20. Due to the phase difference of the two peaks the equal intensities received by a photodetector cancel out and no electrical output is passed to a signal receiver. When a modulating current is superposed on the laser bias current the output beam is changed to either the TE oo or TE o2 mode. In either case the optical fibres then transmit radiation of lesser intensity but of the same phase, and the photo-detector is able to respond. The lens 26 in the radiation path is optional. An alternative arrangement, Fig. 4b, uses a single optical guide of such limited cross-section that only the central peak of the even order TE 00 or TE 02 modes is transmitted. Modulation changes the output beam to an odd order mode, the optical guide being unable to transmit this mode due to its displaced intensity peaks. Alternatively the optical guide may be replaced by a guide transmissive of the lowest mode order only. The arrangement may be used in a PCM system.
GB4653272A 1971-10-08 1972-10-09 Method of and an arrangement for modulating directly a semiconductor laser Expired GB1363029A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7871171A JPS5132463B2 (en) 1971-10-08 1971-10-08

Publications (1)

Publication Number Publication Date
GB1363029A true GB1363029A (en) 1974-08-14

Family

ID=13669436

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4653272A Expired GB1363029A (en) 1971-10-08 1972-10-09 Method of and an arrangement for modulating directly a semiconductor laser

Country Status (2)

Country Link
JP (1) JPS5132463B2 (en)
GB (1) GB1363029A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8757816B2 (en) 2010-10-04 2014-06-24 Hitachi Consumer Electronics Co., Ltd. Laser projector and method of scanning laser beam

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8757816B2 (en) 2010-10-04 2014-06-24 Hitachi Consumer Electronics Co., Ltd. Laser projector and method of scanning laser beam

Also Published As

Publication number Publication date
JPS4844087A (en) 1973-06-25
JPS5132463B2 (en) 1976-09-13
DE2248975B2 (en) 1975-10-02
DE2248975A1 (en) 1973-05-10

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee