Dynamic single-transverse-mode properties of varying ridge width DFB laser arrays

Controlling the lasing wavelength by varying the ridge width is a simple and versatile technique for realizing practical WDM laser arrays. The purpose of this letter is to report the dynamic transverse mode properties of such laser arrays. We show that it is possible to maintain single-mode lasing even for ridges wide enough to support multiple transverse modes. As a result, we were able to increase the tuning range in the array without introducing any detrimental effects on their single-mode properties.