The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 28, 1988
Filed:
Oct. 07, 1985
Applicant:
Inventor:
Leslie D Westbrook, Ipswich, GB;
Assignee:
British Telecommunications plc, London, GB;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01S / ;
U.S. Cl.
CPC ...
372 32 ; 372 44 ; 372 96 ;
Abstract
The emission linewidth of a semiconductor laser can be reduced by operating it at a wavelength which is less than the wavelength of maximum gain at the threshold current, .lambda. max. An assembly for carrying out such operation comprises a ridge waveguide laser provided with a distributed feedback (DFB) grating. The period of the grating is selected to give a predetermined emission wavelength to the laser which is shorter than .lambda. max.