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:
Sep. 14, 1999
Filed:
Oct. 08, 1997
NEC Corporation, Tokyo, JP;
Abstract
First to n-th single-axial-mode LDs are arranged on a semiconductor substrate, where n.gtoreq.2. Each of the first to n-th LDs has a stripe-shaped semiconductor active layer formed on or over the substrate, a stripe-shaped semiconductor guiding layer formed on one side of the active layer, and a stripe-shaped semiconductor cladding layer formed on the other side of the active layer. The guiding layers of the first to n-th LDs have first to n-th diffraction gratings, respectively. The (k+1)-th period is equal to a sum of the k-th period and an increment, where 1.ltoreq.k S (n-1). The active layers of the first to n-th LDs have first to n-th gain peak wavelengths, respectively. The (k+1)-th gain peak wavelength is equal to a sum of the k-th gain peak wavelength and an increment. The first to n-th LDs have first to n-th oscillation wavelengths with first to n-th wavelength differences from the first to n-th gain peak wavelengths, respectively. The first to n-th wavelength differences are within a specific acceptable range for low threshold currents and low wavelength chirping. The lasing characteristic fluctuation is limited within the acceptable range independent of an oscillation wavelength span of the LDs.