Topic
Extinction ratio
About: Extinction ratio is a research topic. Over the lifetime, 8541 publications have been published within this topic receiving 111908 citations.
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Papers
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TL;DR: The design, fabrication, and characterization of a compact photonic crystal nanobeam drop filter based on the tunneling effect of the degenerate modes with an extinction ratio larger than 10 dB and a quality factor of ∼5000 have been experimentally demonstrated.
Abstract: The design, fabrication, and characterization of a compact photonic crystal nanobeam drop filter based on the tunneling effect of the degenerate modes are presented The degeneracy was achieved by tuning the coupling distance between the nanobeam and input/output waveguides The tunneling effect of degenerate resonances with different symmetries has been verified experimentally Channel drop filters with an extinction ratio larger than 10 dB and a quality factor of ∼5000 have been experimentally demonstrated
38 citations
TL;DR: A lateral-apodized add-drop filter is demonstrated in a multimode asymmetric waveguide Bragg grating that utilizes two individual superposed gratings with the same sidewall corrugation depth.
Abstract: A lateral-apodized add–drop filter is demonstrated in a multimode asymmetric waveguide Bragg grating. This design utilizes two individual superposed gratings with the same sidewall corrugation depth. The strong side lobes of the grating filter are efficiently suppressed by mapping the target apodization profile into lateral shifts between the periods of the two gratings. Compared with other apodized technology, this device is easier to be realized. Experimental results show that the side-lobes suppression ratio can reach 18.5 dB, and a bandwidth of 9.5 nm is achieved by a large corrugation width of 150 nm. The insertion loss at the drop port is only 0.8 dB, and the extinction ratio is up to 24 dB at the through port.
38 citations
TL;DR: In this article, the authors show that waveguide coupling to a planar microstructure with a sufficiently long and flat coupling sidewall enables directional wave vector coupling in the micro-structure.
Abstract: We show silicon polygonal microdisk resonators with laterally coupled waveguides Our two-dimensional (2-D) finite-difference time-domain (FDTD) simulations and spatial Fourier analysis reveal that waveguide coupling to a planar microstructure with a sufficiently long and flat coupling sidewall enables directional wave vector coupling in the microstructure Similar analysis shows that waveguide coupling to a polygonal microresonator flat sidewall enables preferential coupling to only a few resonance modes in large-sized polygonal microresonators Our experiments on silicon waveguide-coupled 50-mum octagonal microresonators demonstrate only two dominant modes, with a Q of about 10 4 and an extinction ratio (ER) of about 15 dB We also demonstrate square and hexagonal silicon microresonators with nearly single dominant modes, a Q of the order of 103, and an ER exceeding 10 dB
38 citations
TL;DR: In this paper, a 3D polarizing beam splitter based on a silicon nitride (Si3N4) vertical directional coupler is experimentally demonstrated, where a new planarization technique by incorporating conventional chemical-mechanical lapping with a dry-etching process is developed, in order to obtain a flat film surface for the second Si3N 4 core deposition after the first-layer waveguide is formed.
Abstract: A 3-D polarizing beam splitter based on a silicon nitride (Si3N4) vertical directional coupler is experimentally demonstrated. A new planarization technique by incorporating conventional chemical-mechanical lapping with a dry-etching process is developed, in order to obtain a flat film surface for the second Si3N4 core deposition after the first-layer waveguide is formed. Both the Si3N4 layer thicknesses are 200 nm. As there is a material refractive index mismatch between the vertically separated waveguides, the polarization splitter can be realized with a bottom waveguide width of 1.55 μm and a top core width of 1.35 μm. The transverse electric (TE) polarized light can be transmitted completely to the cross-layer output-port, whereas the transverse magnetic (TM) polarized wave outputs mostly from the port at the input layer. A high-extinction ratio and a wide operation bandwidth can be achieved. An extinction ratio of 26 dB for the cross-layer output-port at 1550-nm wavelength and that of 16 dB for the input-layer output-port are obtained. There is an excess coupling loss of for the TE light, but a 1-dB loss for the TM wave.
38 citations
TL;DR: In this paper, a novel polarization converter using a triangular waveguide is proposed and analyzed by the imaginary distance beam-propagation method based on Yee's mesh and the finite-difference time-domain method.
Abstract: A novel polarization converter using a triangular waveguide is proposed and analyzed by the imaginary-distance beam-propagation method based on Yee's mesh and the finite-difference time-domain method. The polarization conversion length is investigated as a function of relative refractive index difference. It is found, for a silicon core embedded in a silica cladding, that the conversion length is 2 mum, while the insertion loss is 0.5 dB at a wavelength of 1.55 mum. The extinction ratio is more than 20 dB over a wide wavelength range of 1.25 to 1.65 mum. Using a geometrically expanded model, the polarization conversion behavior is verified in the experiment at a microwave frequency of 15 GHz. Finally, reasonable polarization conversion is obtained with a modified structure, in which the two corners of the triangular waveguide are cut and the cut plane is aligned with a square input (output) waveguide.
38 citations