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:
Apr. 09, 1996
Filed:
Feb. 16, 1995
David A Ackerman, Hopewell, NJ (US);
Leonard J Ketelsen, Clinton, NJ (US);
AT&T Corp., Murray Hill, NJ (US);
Abstract
A DFB laser with improved loss grating is disclosed. The grating contains periodically patterned first and second semiconductor layers that are embedded in semiconductor material of composition selected to provide relatively low loss for the laser radiation. The composition of the first layer is selected to provide a relatively high refractive index and loss for the laser radiation, and the composition of the second layer is selected to provide relatively low refractive index and loss for the laser radiation. The thicknesses of the first and second layers are selected such that the real part of the coupling constant .vertline..kappa.'.vertline. is less than the imaginary part of the coupling constant .vertline..kappa.'.vertline.. In preferred embodiments .vertline..kappa.'.vertline..ltoreq.0.5.vertline..kappa.'.vertline., even.ltoreq.0.2.vertline..kappa.'.vertline..