Abstract

Recently, directly UV-written erbium DFB fiber lasers were produced [1,2] and shown to be excellent signal sources for telecommunication [3]. One of their attractive properties compared to semiconductor DFB lasers is the narrow homogeneous linewidth of the gam spectrum leading to reduced crosstalk and allowing cascading of several lasers [3]. Broadening of the gain spectrum and the quantum efficiency of erbium are closely related to the codopants in the fiber core. However, for UV writing certain codopants such as germanium are assumed necessary. More investigations are therefore needed to find optimum combinations of codopants that improve the behavior of the erbium doped fiber without disabling the UV-writing.

© 1996 IEEE