Theoretical Study of Operational Limits of High - Speed Quantum Dot Lasers Report

A comprehensive theory of the modulation response of quantum dot (QD) lasers is developed. The factors limiting the modulation bandwidth are identified and the highest possible bandwidth is calculated. The highest bandwidth increases directly with overlap integral of the electron and hole wave functions in a QD, number of QD-layers, and surface density of QDs in a layer, and is inversely proportional to the inhomogeneous line broadening caused by the QD-size dispersion. At 10% dispersion and 100% overlap, the upper limit for the modulation bandwidth in a single QD-layer laser is as high as 60 GHz. The carrier capture from the waveguide region into QDs strongly limits the modulation bandwidth. As a function of the capture cross-section, the modulation bandwidth asymptotically approaches its highest value when the cross-section increases infinitely (the case of instantaneous capture). With reducing the capture cross-section, the modulation bandwidth decreases and becomes zero at a certain nonvanishing value of the cross-section. The use of multiple-layers with QDs significantly enhances the modulation bandwidth. The internal optical loss, which increases with carrier density in the waveguide region, considerably reduces the modulation bandwidth. With internal loss cross-section increasing and approaching its maximum tolerable value, the modulation bandwidth decreases and becomes zero. (a) Papers published in peer-reviewed journals (N/A for none) Enter List of papers submitted or published that acknowledge ARO support from the start of the project to the date of this printing. List the papers, including journal references, in the following categories: Paper Received Z. N. Sokolova, I. S. Tarasov, L. V. Asryan. Effect of the number of quantum wells in the active region on the linearity of the light-current characteristic of a semiconductor laser, Semiconductors, (08 2012): 1044. doi: 10.1134/S1063782612080222 2012/08/29 01:18:37 17 Yuchang Wu, Robert A. Suris, Levon V. Asryan. Effect of internal optical loss on the modulation bandwidth of a quantum dot laser, Applied Physics Letters, (03 2012): 0. doi: 10.1063/1.3697683 2012/03/27 01:18:06 16 Z. N. Sokolova, I. S. Tarasov, L. V. Asryan. Capture of charge carriers and output power of a quantum well laser, Semiconductors, (11 2011): 0. doi: 10.1134/S1063782611110261 2012/03/02 01:50:10 15 Levon Asryan, Yuchang Wu, Robert Suris. Carrier capture delay and modulation bandwidthin an edge-emitting quantum dot laser, Proc. International Symposium “Nanostructures: Physics and Technology”, (06 2011): 19. doi: 2011/08/10 23:46:51 14 Levon V. Asryan, Yuchang Wu, and Robert A. Suris. Carrier capture delay and modulation bandwidth in an edge-emitting quantum dot laser, Applied Physics Letters, (03 2011): . doi: 2011/04/07 20:54:09 13 Levon V. Asryan, Yuchang Wu, and Robert A. Suris. Capture delay and modulation bandwidth in a quantum dot laser, Proc. SPIE Photonic West, (01 2011): . doi: 2011/04/07 20:30:43 12 Levon V. Asryan. Double Tunneling-Injection Quantum Dot Laser: Temperature-Stable, High-Power, and High-Speed Operation, Proceedings of IEEE Photonics Society Winter Topical Meetings, (01 2010): . doi: 2011/04/07 17:10:48 11 Levon V. Asryan, Robert A. Suris. Maximum modulation bandwidth of a quantum dot laser, Proc. International Symposium "Nanostructures: Physics and Technology", (06 2010): . doi: 2010/07/22 21:13:54 10 Levon V. Asryan, Robert A. Suris. Upper limit for the modulation bandwidth of a quantum dot laser, Applied Physics Letters, (06 2010): . doi: 2010/06/07 14:41:14 9 Levon V. Asryan, Robert A. Suris. Theory of relaxation oscillations and modulation response of a quantum dot laser, Proceedings of the Society for Photo-Optical Instrumentation Engineering, (01 2010): . doi: 2010/04/15 00:15:45 8 Dae-Seob Han, Levon V. Asryan. Double tunneling-injection quantum dot laser: Effect of the wetting layer, Proceedings of the Society for Photo-Optical Instrumentation Engineering, (01 2010): . doi: 2010/04/15 00:06:55 7 Dae-Seob Han, Levon V Asryan. Output power of a double tunneling-injection quantum dot laser, Nanotechnology, (01 2010): . doi: 2010/04/14 23:56:34 6 Dae-Seob Han, Levon V. Asryan. Effect of the Wetting Layer on the Output Power of a Double Tunneling-Injection Quantum-Dot Laser, IEEE Journal of Lightwave Technology, (12 2009): . doi: 2010/04/14 23:48:06 5