| 1. |
- Song, Jun, et al.
(författare)
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Echelle grating demultiplexers with reduced return loss by using chirped diffraction order design
- 2006
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 18:14, s. 1506-1508
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Tidskriftsartikel (refereegranskat)abstract
- A design for echelle grating demultiplexers is presented to reduce the return loss. The input waveguide is placed on the minimal intensity position of the diffraction envelope. Then, by further chirping the diffraction order for each facet, we minimize the envelope intensity for other adjacent diffraction orders, which can contribute to a negligible return loss for a large spectral width. The present design is appropriate for multifrequency laser or multistage demultiplexer applications.
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| 2. |
- Song, Jun, et al.
(författare)
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Effects of surface roughness on the performance of an etched diffraction grating demultiplexer
- 2006
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Ingår i: Journal of the Optical Society of America A: Optics and Image Science, and Vision. - 1084-7529. ; 23:3, s. 646-650
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Tidskriftsartikel (refereegranskat)abstract
- The fabrication tolerance of surface roughness on the performance [such as the insertion loss, the polarization-dependent loss (PDL), and the chromatic dispersion] of an etched diffraction grating demultiplexer is analyzed by using an accurate method of moments. The results show that both the insertion loss and the chromatic dispersion rapidly increase as the roughness of the grating facets increases. Appropriate residual roughness of the shaded facets can reduce the PDL of the demultiplexer, and the mechanism for the existence of an optimal residual roughness is explained.
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| 3. |
- Song, Jun, et al.
(författare)
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Etched diffraction grating demultiplexers with large free-spectral range and large grating facets
- 2006
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 18:24, s. 2695-2697
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Tidskriftsartikel (refereegranskat)abstract
- A design for etched diffraction grating demultiplexers is presented to obtain both large grating facets and a larger free-spectral range (FSR) using the optimal chirped diffraction orders for different facets. The large grating facets by using a large diffraction order contribute to lowering the manufacturing difficulty, and can provide lower polarization-dependent loss. However, usually the large diffraction order must lower the FSR of the device by all means. Based on the present design, the FSR can overlay the whole diffraction envelop for a special order, but avoid the influence of the adjacent diffraction envelops. Calculations indicate that the extinction ratio between the operated order and adjacent orders can attain a 35 dB or so, which makes the crosstalk from channels in adjacent envelops to those in the operated diffraction envelop acceptable.
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| 4. |
- Song, Jun, et al.
(författare)
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Sidelobe suppression design of etched diffraction grating demultiplexers using optimized air trenches in front of each output waveguide
- 2006
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Ingår i: Journal of the Optical Society of America A: Optics and Image Science, and Vision. - 1084-7529. ; 23:10, s. 2645-2649
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Tidskriftsartikel (refereegranskat)abstract
- An etched diffraction grating (EDG) demultiplexer with high sidelobe suppression is designed. Sidelobes resulting from two adjacent wavelengths are suppressed by etching two optimized rectangular air trenches in front of each output waveguide that can induce large resonance loss in the adjacent wavelength but have little influence on the operational wavelength. The designed EDG demultiplexer can suppress crosstalk to less than 50 dB in theory.
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| 5. |
- Wang, Zhechao, et al.
(författare)
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Experimental demonstration of an ultracompact polarization beam splitter based on a bidirectional grating coupler
- 2009
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Ingår i: 2009 Asia Communications and Photonics Conference and Exhibition, ACP 2009. - 9781557528773 ; , s. 5377257-
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Konferensbidrag (refereegranskat)abstract
- A bidirectional grating serving both as a polarization beam splitter and a vertical coupler for Silicon on Insulator nanophotonic circuits is fabricated and characterized. The measured coupling efficiency is as high as 43%. The demonstrated device has a large 3-dB bandwidth and a high extinction ratio between two orthogonal polarizations.
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| 6. |
- Wang, Zhechao, et al.
(författare)
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Ultracompact low-loss coupler between strip and slot waveguides
- 2009
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 34:10, s. 1498-1500
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Tidskriftsartikel (refereegranskat)abstract
- We present both theoretical and experimental results of an ultracompact waveguide coupler that is capable of highly efficient coupling of light from strip waveguides to slot waveguides, and vice versa. By optimizing the geometrical parameters, it is possible to achieve extremely low-loss coupling. A coupling efficiency of 97% has been obtained experimentally while keeping the overall size down to the range below 10 mu m. Further analysis shows that the proposed coupler has relatively high tolerance to fabrication errors and is wavelength insensitive. (C) 2009 Optical Society of America
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| 7. |
- Zhu, Ning, et al.
(författare)
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A hybrid modeling for the theoretical analysis of reflections in a multimode-interference coupler based on silicon-on-insulator nanowires
- 2008
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Ingår i: Optics Communications. - : Elsevier BV. - 0030-4018 .- 1873-0310. ; 281:11, s. 3099-3104
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Tidskriftsartikel (refereegranskat)abstract
- A hybrid method combining the three-dimensional (3D) beam propagation method (BPM) and a 3D finite-difference time-domain (FDTD) method is presented for the simulation of multimode-interference (MMI) couplers based on silicon-on-insulator (SOI) nanowires. This hybrid method makes it possible to have a robust analysis for the reflection properties while avoiding a time-consumed computation with a simplex 3D-FDTD simulation. The reflected power is sensitive to both the length and the width of the MMI coupler and thus one should choose the optimal values for good self-imaging. Furthermore, the reflection could be reduced by introducing tapers between the MMI section and the access waveguides.
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| 8. |
- Zhu, Ning, et al.
(författare)
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Bragg grating-assisted optical triplexer using two silicon nanowire-based directional couplers
- 2009
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Ingår i: 2009 Asia Communications and Photonics Conference and Exhibition, ACP 2009. - Washington, D.C. : OSA. - 9781557528773 ; , s. 5377094-
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Konferensbidrag (refereegranskat)abstract
- A triplexer based on silicon nanophotonic wire structure consisting of two Bragg grating-assisted directional couplers is proposed. The device has low loss, low crosstalk, and a footprint of only 210 x40 μm, The 1-dB bandwidth for the three channels located at 1310, 1490 and 1550 nm are 110, 20, and 20 nm, respectively.
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| 9. |
- Zhu, Ning, et al.
(författare)
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Cross-Order Echelle Grating Triplexer Based on Amorphous Silicon Nanowire Platform
- 2008
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Ingår i: 2008 7TH INTERNATIONAL CONFERENCE ON THE OPTICAL INTERNET (COIN). - NEW YORK : IEEE. - 9784885522307 ; , s. 37-38
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Konferensbidrag (refereegranskat)abstract
- We present fabrication and measurement results of an ultracompact silicon-on-insulator-based echelle-grating triplexer, which uses different diffraction orders to cover a large spectral range from 1.3 mu m to 1.5 mu m, with a footprint of 150 mu m x 200 mu m.
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| 10. |
- Zhu, Ning, et al.
(författare)
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Design of a polarization-insensitive echelle grating demultiplexer based on silicon nanophotonic wires
- 2008
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Ingår i: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 20:9-12, s. 860-862
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Tidskriftsartikel (refereegranskat)abstract
- A polarization-insensitive design of an echelle grating (or etched diffraction grating) demultiplexer based on silicon nanowires is proposed in the present letter, by introducing a polarization compensation area in its free propagation region. The polarization-dependent wavelength shift of the present device has been compensated at the whole spectral range. For a design with nine channels and 10-nm channel spacing, when the wavelength shift at the central channel 1550 nm is. completely compensated, the wavelength shifts of the two edge channels are only 0.14 and 0.15 nm, which are acceptable.
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