2,134 research outputs found
The Rise and Fall of Fences: The Overbroad Protection of the Anticybersquatting Consumer Protection Act
Jonathan Ward discusses viability of two means for resolution of disputes related to cybersquatting. Cybersquatting occurs when a party registers a domain name that contains someone else\u27s trademark and then attempts to profit by selling or licensing the name to that party. Cybersquatting tends to be classified as direct cybersquatting and typosquatting, and actions involving domain name conflicts fall in four categories: 1) trademark infringement, 2) confusion of source, 3) dilution of a famous mark, and 4) bad faith registration. Recognizing the growing issue of cybersquatting, Congress passed the Anitcybersquatting Consumer Protection Act in 1999, which provided a litigious avenue for dispute resolution. Around the same time, ICANN (the assignor of domain names) adopted the Uniform Domain Name Dispute Resolution Policy, which provided an alternative dispute resolution avenue through arbitration. Mr. Ward presents a comparison between these two options, and concludes that the best method depends on which channel of recourse offers the most benefits at the lowest cost
Complete polarization control for a nanofiber waveguide using directional coupling
Optical nanofiber waveguides are widely used for near-field delivery and
measurement of light. Despite their versatility and efficiency, nanofibers have
a critical drawback - their inability to maintain light's polarization state on
propagation. Here, we design a directional coupler consisting of two crossed
nanofibers to probe the polarization state at the waist region. Directionality
of coupling occurs due to asymmetric dipolar emission or spin-locking when the
evanescent field pattern breaks the mirror symmetry of the crossed-nanofiber
system. We demonstrate that, by monitoring the outputs from the directional
coupler, two non-orthogonal polarization states can be prepared at the
nanofiber waist with a fidelity higher than 99%. Based on these states, we
devise a simple and reliable method for complete control of the polarization
along a nanofiber waveguide.Comment: 8 pages, 8 figure
All-Optical Nanopositioning of High-Q Silica Microspheres
A tunable, all-optical, coupling method has been realized for a
high-\textit{Q} silica microsphere and an optical waveguide. By means of a
novel optical nanopositioning method, induced thermal expansion of an
asymmetric microsphere stem for laser powers up to 171~mW has been observed and
used to fine tune the microsphere-waveguide coupling. Microcavity displacements
ranging from (0.612~~0.13) -- (1.5 0.13) m and nanometer scale
sensitivities varying from (2.81 0.08) -- (7.39 0.17) nm/mW, with
an apparent linear dependency of coupling distance on stem laser heating, were
obtained. Using this method, the coupling was altered such that different
coupling regimes could be explored for particular samples. This tunable
coupling method, in principle, could be incorporated into lab-on-a-chip
microresonator systems, photonic molecule systems, and other nanopositioning
frameworks.Comment: 6pages,4figure
Cavity ring-up spectroscopy for dissipative and dispersive sensing in a whispering gallery mode resonator
In whispering gallery mode resonator sensing applications, the conventional
way to detect a change in the parameter to be measured is by observing the
steady state transmission spectrum through the coupling waveguide.
Alternatively, cavity ring-up spectroscopy (CRUS) sensing can be achieved
transiently. In this work, we investigate CRUS using coupled mode equations and
find analytical solutions with a large spectral broadening approximation of the
input pulse. The relationships between the frequency detuning, coupling gap and
ring-up peak height are determined and experimentally verified using an
ultrahigh \textit{Q}-factor silica microsphere. This work shows that
distinctive dispersive and dissipative transient sensing can be realised by
simply measuring the peak height of the CRUS signal, which might improve the
data collection rate
Optomechanical Transduction and Characterization of a Silica Microsphere Pendulum via Evanescent Light
Dissipative optomechanics has some advantages in cooling compared to the
conventional dispersion dominated systems. Here, we study the optical response
of a cantilever-like, silica, microsphere pendulum, evanescently coupled to a
fiber taper. In a whispering gallery mode resonator the cavity mode and motion
of the pendulum result in both dispersive and dissipative optomechanical
interactions. This unique mechanism leads to an experimentally observable,
asymmetric response function of the transduction spectrum which can be
explained using coupled-mode theory. The optomechanical transduction, and its
relationship to the external coupling gap, are investigated and we show that
the experimental behavior is in good agreement with the theoretical
predictions. A deep understanding of this mechanism is necessary to explore
trapping and cooling in dissipative optomechanical systems.Comment: 5 page
Thermo-optical tuning of whispering-gallery modes in Er:Yb co-doped phosphate glass microspheres
We demonstrate an all-optical, thermally assisted technique for broad-range tuning of whispering gallery modes in microsphere resonators fabricated from an Er:Yb co-doped phosphate glass (IOG-2). The microspheres are pumped at 978 nm and the heat generated by absorption of the pump expands the cavity, thereby altering the cavity size and refractive index. We demonstrate a significant nonlinear tuning range of greater than 700 GHz of both C- and L-band cavity emissions via pumping through a tapered optical fibre. Finally, we show that large linear tuning up to ∼488 GHz is achievable if the microsphere is alternatively heated by coupling laser light into its support stem
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