Low-threshold monomode ion-exchanged waveguide lasers in neodymium-doped BK-7 glass

Abstract

The ion exchange technique has been advanced as method of fabrication of active integrated optic devices in glass substrates. Multimode waveguides have previously been made in rare-earth doped glasses and optically pumped to provide amplifying media or lasers. However lasers fabricated using single-mode waveguides have lower thresholds than multimode devices. In this paper we report the first demonstration of a monomode ion exchanged laser in neodymium doped BK-7 glass. The technique is suitable for batch processing of devices at low cost. In addition the waveguide fields can be easily perturbed in the planar geometry enabling a variety of devices such as modulators, ring and coupled-cavities, and wavelength multiplexers to be integrated. Development of active integrated optic devices in glass has been hampered by lack of rare-earth doped glasses with suitable ion exchange chemistry. In our case this drawback has been removed by selecting an ion-exchangeable glass and doping it with the required rare-earth ions. This also allows variation of the dopant concentration to optimise laser performance. BK-7 was chosen as the basic glass because of its good optical quality and excellent ion exchange properties with silver, potassium and caesium ions which allow waveguides with a wide range of numerical apertures to be easily fabricated.
In our studies BK-7 glass was doped with 2 wt% neodymium oxide to form the substrate. Single-transverse-mode waveguide lasers were fabricated in the substrate by potassium ion exchange.

More information

Identifiers

ORCID for J.S. Wilkinson: orcid.org/0000-0003-4712-1697

Catalogue record

Export record

Altmetrics