http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Research on the physical origin of nonlinear gain in semiconductor lasers
Since the invention of semiconductor diode lasers, the issue regarding the physical origin of gain nonlinearity in these devices has been a subject of great controversy. An important aspect of this research to investigate the cause of gain nonlinearity in semiconductor laser. The nonlinearity in the gain medium caused by the optical density at an arbitrary wavelength is calculated using Maxwell's equations. In this calculation, we assume that stimulated emission induced a perturbation in the dielectric function through some physical process (or processes). The contending process is generally thought to be spectral-hole burning or hot carriers, each characterized by a certain relaxation time constant. The goal of this research is to determine this relaxation time constant, τ, and infer, from the magnitude of x, the physical process responsible for the nonlinear gain. Measurement of gain nonlinearity were made on a wavelength-tunable traveling-wave ring laser. It was found for the first time that the dominant process is spectral-hole burning with τ=50 femtosecond. Hot carriers process was also evident from the data, but its magitude is only 10~20 % of spectral-hole burning. We also show (Appendix D) that our result does not contradict the time domain experiment of the MIT group. We conclude that their nonlinear parameters may not be the only possible set that fits their data.
"Major subject: Electrical Engineering."