Slowing down the velocity of light has raised fundamental questions related to our understanding of light-matter interactions as well as promised new possibilities for photonic devices. Within the framework of NATEC we have demonstrated that slow light can be used to control and increase the gain coefficient of an active semiconductor waveguide. The results indicate a route towards realizing ultra-compact optical amplifiers for linear as well as nonlinear applications in integrated photonics but also identifies challenges that require further research in such structures.

Schematic of an active membrane exposed to a focused pump beam (green) and the fibre collecting light from a taper. b-d) SEM images showing b) the taper, c) the active material in the center of the membrane, and d) the photonic crystal membrane.

We work on the following topics:

• The demonstration of slow-light enhanced gain
• The study of saturation effects in slow-light photonic crystal amplifiers
• Gain limitation due to fundamental gain-index coupling
• Lasing in Anderson localized modes
• Pump-probe dynamics in quantum-dash semiconductor optical amplifiers

Relevant NATEC papers:

S. Ek, P. Lunnemann, Y. Chen, E. Semenova, K. Yvind, and J. Mork, “Slow-light-enhanced gain in active photonic crystal waveguides.,” Nat. Commun., 5, 5039, (2014).

J. Liu, P. D. Garcia, S. Ek, N. Gregersen, T. Suhr, M. Schubert, J. Mørk, S. Stobbe, and P. Lodahl, “Random nanolasing in the Anderson localized regime.”, Nat. Nanotechnol. 9, 285–9 (2014).

J. Mørk and T. R. Nielsen, “On the use of slow light for enhancing waveguide properties”, Opt. Lett. 35, 2834–2836 (2010).

J. Grgic, J. R. Ott, F. Wang, O. Sigmund, A.-P. Jauho, J. Mørk, and N. A. Mortensen, “Fundamental Limitations to Gain Enhancement in Periodic Media and Waveguides”, Phys. Rev. Lett. 108, 183903 (2012).

Y. Yu, M. Heuck, S. Ek, N. Kuznetsova, K. Yvind, J. Mork, and J. Mørk, “Experimental demonstration of a four-port photonic crystal cross-waveguide structure”, Appl. Phys. Lett. 101, pages (2012).

P. Lunnemann, S. Ek, K. Yvind, R. Piron, and J. Mørk, “Nonlinear carrier dynamics in a quantum dash optical amplifier”, New J. Phys. 14, 013042 (2012).

Y. Chen and J. Mørk, “Theory of carrier depletion and light amplification in active slow light photonic crystal waveguides”, Opt. Express 21, 29392–29400 (2013).