Aberration properties in a chirped grating for coarse wavelength division demultiplexing
ABSTRACT We studied the imaging performance of a chirped grating for a demultiplexer designed for coarse wavelength division multiplexing using a wavefront aberration analysis and the ray tracing simulation. The demultiplexer was composed of a chirped grating, cylindrical lenses, and a waveguide. The best image point and the spot shape focused by the chirped grating were effectively calculated with the wavefront aberration. We applied the aberration analysis to design a waveguide to connect branched beams to photodetectors, and we confirmed the demultiplexing performance experimentally.
SourceAvailable from: Niru K Nahar[Show abstract] [Hide abstract]
ABSTRACT: A scheme is presented here to lower the free-space coupling loss to large mode area (LMA) photonic crystal fiber (PCF). A numerical study (using optics software for layout and optimization/beam propagation method) has been performed which demonstrates that the major source of coupling loss is due to the aberrations present in the optical system (using bulk optics) creating a source beam with appropriate size to couple into the LMA-35. We show that by carefully choosing a single or multiple aspheric lenses the wavefront aberrations can be minimized and the coupling loss into the LMA-PCF can be reduced to only 0.5 dB.IEEE Transactions on Components, Packaging, and Manufacturing Technology 10/2011; 1(10):1553-1557. DOI:10.1109/TCPMT.2011.2165712 · 1.24 Impact Factor
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ABSTRACT: A chirped grating segmented into partitions each having a constant blaze angle to use in a demultiplexer for coarse wavelength division multiplexing with multimode optical fibers is developed. Its designed configuration utilizes a resonance region to achieve high diffraction efficiency and large dispersion. The width, blaze angle, and diffraction order of each partition were optimized by vector diffraction analysis. The diffraction loss of the manufactured grating was less than 1.5 dB, and polarization-dependent loss was less than 0.6 dB within a wavelength width of at least 70 nm. It is confirmed that a demultiplexer with the developed chirped grating had a wide passband and low cross talk.Applied Optics 06/2007; 46(15):2817-24. DOI:10.1364/AO.46.002817 · 1.69 Impact Factor