Virginia TechPochet, M.Usechak, N. G.Schmidt, J.Lester, L.2014-04-042014-04-042014-01-01Michael Pochet, Nicholas G. Usechak, John Schmidt, and Luke F. Lester, "Modulation response of a long-cavity, gain-levered quantum-dot semiconductor laser," Opt. Express 22, 1726-1734 (2014). doi: http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-22-2-17261094-4087http://hdl.handle.net/10919/46935The gain-lever effect enhances the modulation efficiency of a semiconductor laser when compared to modulating the entire laser. This technique is investigated in a long-cavity multi-section quantum-dot laser where the length of the modulation section is varied to achieve 14:2, 15:1 and 0:16 gain-to-modulation section ratios. In this work, the gain-levered modulation configuration resulted in an increase in modulation efficiency by as much as 16 dB. This investigation also found that the 3-dB modulation bandwidth and modulation efficiency are dependent on the modulation section length of the device, indicating the existence of an optimal gain-to-modulation section ratio. The long cavity length of the multi-section laser yielded a distinctive case where characteristics of both the gain-lever effect and spatial effects are observed in the modulation response. Here, spatial effects within the cavity dominated the small-signal modulation response close to and above the cavity's free-spectral range frequency, whereas the gain-lever effect influenced the modulation response throughout the entirety of the response.application/pdfenIn CopyrightBandwidth enhancementInjectionsArticle - Refereedhttp://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-22-2-1726https://doi.org/10.1364/OE.22.001726