A unidirectional quantum cascade ring laser

Nshii, C. and Ironside, C. and Sorel, M. and Slight, T. and Zhang, S. and Revin, D. and Cockburn, J. 2010. A unidirectional quantum cascade ring laser. Applied Physics Letters. 97 (23).

Source Title

Applied Physics Letters

DOI

10.1063/1.3524200

ISSN

0003-6951

School

Department of Physics and Astronomy

URI

http://hdl.handle.net/20.500.11937/19043

Collection

Curtin Research Publications

Abstract

We report on the design, fabrication, and characterization of a unidirectional quantum cascade ring laser operating at a wavelength of around 3.4 µm at 200 K. A unidirectional operation is achieved by incorporating an "S-shaped" crossover waveguide in a manner that it couples light from the counterclockwise direction to the preferred clockwise direction. The ring laser unidirectionality is confirmed by measuring the counterpropagating wave suppression ratio (CWSR) as a function of injection current. At 1.5 times the threshold current, the CWSR is 9 that is 90% of the light is emitted in the favored (clockwise) direction. © 2010 American Institute of Physics.