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:
Dec. 16, 1997
Filed:
Apr. 29, 1996
Applicant:
Inventors:
Assignee:
British Telecommunications public limited company, London, GB;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01S / ; G02B / ; G02B / ;
U.S. Cl.
CPC ...
372102 ; 372 92 ; 372108 ; 385 14 ; 385 42 ; 385130 ; 385131 ; 359589 ; 359590 ;
Abstract
An optical filter is formed from at least two gratings (102,103) located in a waveguide region (104) of a` semiconductor optical device (101). Each grating has a multiple peak optical passband. The gratings are spaced apart in the waveguide region and form an optical cavity having a comb-filter characteristic. The gratings may be located in the active region of an optical gain element and in a preferred example are superstructure gratings (SSGs). A number of filters may be joined together in series.