Spectroscopic Studies of Erbium-Titanium Codoping of Lithium Niobate Waveguides for Active Device Applications,
Abstract
Erbium doped optical fibres have proved to be very useful optical amplifiers and are currently being installed in optical communications systems. The prospect of extending the concept to integrated optical formats and doping electro-optic materials such as Lithium Niobate with rare earth laser active ions has attracted considerable interest. The device objectives are to produce laser media with modulation capabilities. In this paper we discuss a convenient technique which combines fabrication of the waveguide with Er doping. A waveguide Er laser fabricated in LiNbO3 has recently been demonstrated. The technique used to dope the waveguide with Er was diffusion doping where a thin layer approx. 10.7 nm, of Er metal is deposited on the surface of the z-cut LiNbO3; the coated LiNbO3 is then placed in a furnace a 1060 C for 80 hours. The Er diffuses into the top 5 micrometers layer of the material. Subsequently Ti waveguides are fabricated in the doped material by the usual methods. An important point is that inhomogeneous doping of the waveguide is obtained by this method compared to the homogeneous doping that is obtained if the Er is introduced at the crystal growth stage. If we compare the Er laser with the Nd laser an important difference is that the Er laser is a three level laser compared to the Nd laser which is a four level laser. Consequently if an Er doped part of the laser medium is not pumped and thereby is not contributing gain it is contributing loss. Whereas in the Nd laser unpumped parts of the laser medium do not contribute loss.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1992
- Accession Number
- ADP008217
Entities
People
- C. N. Ironside
- Fangjie Zhou
- P. S. Jiang
- R. M. Delarue
- T. Han
Organizations
- University of Glasgow