Tunable laser sources for (D)WDM

Abstract

For several years tunable lasers and other WDM sources has been as one of the hottest components topics in photonics, but like other areas the downturn has hit hard. In this paper we will describe the latest developments in the area of optical sources for DWDM systems, including tunable lasers and multiwavelength sources, and we will look at the companies (still) competing in this area. We will start by introducing the basic technologies used for DWDM sources. After that we will give an overview of the source options, and discuss tuning methods and wavelength control issues. The source options under discussion will include monolithic tunable lasers, hybrid structures and external cavity lasers, wavelength selectable laser arrays, tunable VCSELs, and non-semiconductor alternatives. Numerous examples will be shown, and the characteristics and performance of the various devices will be discussed. The key performance parameters, such as tuning range, power and switching speed will be related to the expected areas of application. These areas include sparing, fixed wavelength transmitter replacement, and use in wavelength switched networks.