No abstract

SudarshanSivaramakrishnan received the B.S.E. degree in electrical engineering and the B.S. degree in mathematics in 2010, and the M.S.E. degree in electrical engineering in 2012, from the University of Michigan, Ann Arbor. He is currently pursuing the Ph.D. degree in electrical engineering within the concentration of optics/photonics. His research work includes fiber lasers and nonlinear optics. electrical engineering with a minor in optics from the University of Michigan, Ann Arbor, in 2012, with the study of passive and active fiber laser array coherent beam combining. He is currently a Researcher with IMRA America, Inc., working on rare-earthdoped ultrafast fiber oscillators and amplifiers, and frequency comb systems.Almantas Galvanauskas is currently a Professor with the Electrical Engineering and Computer Science Department, University of Michigan. He has been involved in fiber lasers for over 20 years, and has over 200 publications, including approximately 30 patents and patent applications. He had pioneered ultrashort-pulse fiber CPA, and his work had resulted in demonstrating several record-breaking achievements in performance of fiber lasers. Prior to joining the University of Michigan, he spent eight years in industrial R&D. His current work spans areas from novel fiber designs to advanced fiber laser systems, including spatially, temporally, and time multiplexing of ultrashort pulse signals, and new fiber laser applications, such as high-intensity laser plasma produced EUV and X-ray generation, and particle generation and laser plasma acceleration.

No abstract

We show that coupled mode-locked semiconductor lasers can operate in a subharmonic regime in which the two lasers pulsate in an anti-phase manner at one-half the fundamental mode-locking frequency of the solitary lasers. In the subharmonic mode, each pulse has almost twice the energy carried by the isolated lasers in the fundamental mode-locked regime and is also significantly shorter in duration. Depending on the unsaturated gain and coupling strength, the lasers can also exhibit bistability, perfect synchronization, and delayed synchronization, as well as three-halves and five-halves harmonic mode locking. The observed behaviors are robust and persist in the presence of noise.

Two laboratory projects for an introductory service course in Electrical Engineering (EE) for non-EE engineering majors relate the abstract concepts of Fourier spectra and transfer functions of filters to the students' favorite applications-creating and listening to the sounds of music. The projects include: (a) use of technology/software available on the Internet for the production of sounds and editing of audio files; (b) lab measurements of the waveforms and spectra of music, along with listening to the sounds; (c) soldering a multi-functional passive filter circuit and measurements of its transfer functions; (d) listening to the sounds of music without filters, through the software filters and through the real, soldered filters, and (e) comparison of the effects of these two types of filters on the sensory perception of the sounds of music. Here we explain the content of each project and its place in the sequence of rigorous measurements of standard signals; provide examples of lab data, and summarize the feedback from students and from the lab instructors in a large class.