CLEO:2013 Conference Report
Ryo Suzuki, 1st year master student, Tanabe Laboratory
June 20, 2013
We gave a poster presentation at CLEO:2013 (Conference on Lasers and Electro-Optics) held in San Jose, U.S.A. from June 9 to 14, 2013, and attended presentations on related research. We also visited Yamamoto Laboratory at Stanford University. We report on our participation in these conferences.
San Jose, where the conference was held, is the central city of Silicon Valley, where Hewlett-Packard and other world-class IT companies are concentrated. Although it was the first time for me to visit the U.S. mainland, I was able to participate in the conference with relative peace of mind. As for the contents of the presentations, there were many topics on micro optical resonators, which are rarely seen at conferences in Japan, and I was able to experience firsthand the speed and high level of research being conducted by researchers around the world.
Presentation (poster) report]
I gave a poster presentation titled "Octagonal toroidal microcavity for mechanically robust coupling with optical fiber. Since it was late in the day, from 18:30 to 20:30, food and alcohol were served next to the venue, and discussions were held in a friendly atmosphere. On average, their prior knowledge of silicatroids was limited to the level that they had heard of silicatroids, although they were not familiar with them. Since I had memorized a template of possible questions and answers, I felt that I was able to exceed the minimum line of answering the questions asked by the audience. However, I was not able to engage in in-depth discussions due to my limited English skills. For example, I was asked about potential applications of Optomechanics, but I was not able to express my response well, which was very regrettable. I will try to improve my English in the future, as it is quite possible that I will go to international conferences again during my master's program.
Research focused on...
QM1A.4 Xiao Group "Ultralow-threshold cavity Raman laser via free-space excitation"
This is an experiment of Raman laser using a toroidal resonator. Although Raman lasers are not novel, as presented by the Vahala Group in 2002, the key point of this study is a coupling method that does not use tapered fibers. As the title of the paper says "free-space excitation," the input/output is performed by focusing the light with a lens as shown in the figure below. If the toroidal resonator is circular, the input and output directions are different and this method cannot be used. Therefore, the direction is controlled by intentionally generating distortion. However, even with this distortion, a Q value on the order of 108 is achieved.
ATh5A.1 Bergman Group "Simplified Platform for Microring-Sensing using Wavelength Locking"
This research was published as a post-deadline paper. Sensing applications of optical resonators are performed by observing the shift in the resonance wavelength caused by the attachment of target particles. The observation has been performed using wavelength tunable lasers or broadband lasers, but a method using a single wavelength laser is proposed here. The system consists of a silicon microring resonator with a voltage-controlled heater attached to it, enabling the resonance wavelength to be controlled by heat. As shown in the figure below, a laser with a single wavelength is input with the wavelength shifted by Δλ0 from the resonance wavelength, the resonance wavelength is changed by the heater, and the wavelength change until the light couples is measured. In other words, if there is no object attached, coupling occurs when Δλ0 is changed, and if an object is attached, coupling occurs when Δλ0-ΔλRS is changed. This ΔλRS is the wavelength shift due to particle adhesion, and is determined by the magnitude of the voltage.
QTh4E.3 Kippenberg Group "Soliton mode-locking in optical microresonators"
Among the many presentations on optical frequency comb, the trend since the end of last year seems to be soliton mode-locking in these resonators. When coupling sweeps from short wavelengths to long wavelengths, noise is reduced from a certain point and mode-locking occurs. Half of the presentation is about a 2012 Nature Photonics paper from the same group, "Universal formation dynamics and noise of Kerr-frequency combs in microresonators The importance of understanding this paper was apparent.