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Detection, correction ease light coupling (10/18/2004) |
Dutch electronics giant Philips has revealed details of a new method for coupling light into a light guide using error-detecting and correcting systems (WO 2004/055564). First, a rectangular light guide is mated with an x-axis optical fibre and a y-axis optical fibre. Two discrete (x- and y-axis) photodetectors sense light that couples out of the light guide into the x- and y-axis fibres. According to the filing, an error detector compares the outputs of the x-axis and the y-axis photodetectors to produce error signals that depend on the x-, y- and z-axis positional errors. An error-correcting system subsequently adjusts the relative position of the light guide and the light directed into it. (fibers.org) |
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Electrically Driven Single-Cell Photonic Crystal Laser (9/15/2004) |
Korea Scientists reported the experimental demonstration of an electrically driven, single-mode, low threshold current (260 ¦ÌA) photonic band gap laser operating at room temperature. The electrical current pulse is injected through a sub-micrometer-sized semiconductor wire at the center of the mode with minimal degradation of the quality factor. As a small step toward a thresholdless laser or a single photon source, this wavelength-size photonic crystal laser may be of interest to photonic crystals, cavity quantum electrodynamics, and quantum information communities. (Science Magzine) |
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Cut glass plate with a laser (8/31/2004) |
Rorze Systems Corporation,Korea invents the optimal way to cut glass sheets with a laser,which is the subject of patent application WO 2004/060823. This Korean firm believes
the first step is to irradiate the glass plate with a 0.05-0.2 J/mm2 spot from a carbon dixode laser.
The plate is then cooled with water to generate a scribe line. A second 0.1-0.5 J/mm2 carbon dixode beam
follows the scribe line to cut the glass. The inventors say that the optimal laser spot size in
both cases is between 20 to 200 mm2. (optics.org) |
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