Ultracompact polarization splitter-rotator based on an asymmetric directional coupler.
ABSTRACT An ultracompact polarization splitter-rotator based on an asymmetric directional coupler has been designed and analyzed. The device consists of one channel waveguide and one vertical slot waveguide, which couple to each other to form the asymmetric directional coupler. The coupling length is only 17.4 μm, and the polarization extinction ratio, with its largest value of 18 dB, is more than 15 dB in the operating wavelength range from 1515 to 1560 nm. The TM-to-TE conversion efficiency can reach up to 95% (0.02 dB) at 1550 nm wavelength.
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ABSTRACT: A novel silicon-on-insulator (SOI) polarization splitter-rotator is proposed based on mode-evolution tapers and a mode-sorting asymmetric Y-junction. The tapers are designed to adiabatically convert the input TM0 mode into the TE1 mode, which will evolve into the TE0 mode in the wide output arm while the input TE0 mode excites the TE0 mode in the narrow arm. The numerical simulation results show that the mode conversion efficiency increases with the lengths of the tapers and the Y-junction for the output waveguide widths in a large range. This proposed device has < 0.4 dB insertion loss with > 12 dB extinction ratio in an ultra-broad wavelength range from 1350 nm to 1750 nm. With such a broad operating bandwidth, this device offers potential applications for polarization diversity operating across every communication bands. Fabrication tolerance analysis is also performed in terms of the device width variation, the slab height variation and the variation of the upper-cladding refractive index.Optics Express 06/2014; 22(11):13565-13571. DOI:10.1364/OE.22.013565 · 3.53 Impact Factor
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ABSTRACT: In this letter, we propose a hybrid plasmonic polarization rotator (PR) utilizing asymmetrical directional coupling between a hybrid plasmonic waveguide and a strip Si dielectric waveguide (DW), which features ultracompact size, low insertion loss (IL), and silicon-on-insulator compatibility. The coupling length is only 11.2 μm, much shorter than the PRs based on asymmetrical directional coupling between two strip DWs on the same silicon core layer with the same coupling gap. The presented PR shows a high polarization conversion efficiency (PCE) of 99.9% at 1550 nm with an IL of 0.136 dB, which is extremely low in the reported plasmonic PRs. In addition, it yields the PCE better than 96% and the IL lower than 0.42 dB over a bandwidth of 60 nm.IEEE Photonics Technology Letters 02/2015; 27(3):229-232. DOI:10.1109/LPT.2014.2365294 · 2.18 Impact Factor
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ABSTRACT: A novel silicon-on-insulator (SOI) polarization splitter-rotator (PSR) with a large fabrication tolerance is proposed based on cascaded multimode interference (MMI) couplers and an assisted mode-evolution taper. The tapers are designed to adiabatically convert the input TM0 mode into the TE1 mode, which will output as the TE0 mode after processed by the subsequent MMI mode converter, 90-degree phase shifter (PS) and MMI 3 dB coupler. The numerical simulation results show that the proposed device has a < 0.5 dB insertion loss with < −17 dB crosstalk in C optical communication band. Fabrication tolerance analysis is also performed with respect to the deviations of MMI coupler width, PS width, slab height and upper-cladding refractive index, showing that this device could work well even when affected by considerable fabrication errors. With such a robust performance with a large bandwidth, this device offers potential applications for CMOS-compatible polarization diversity, especially in the booming 100 Gb/s coherent optical communications based on silicon photonics technology.Optics Express 11/2014; 22(23):27869-27879. DOI:10.1364/OE.22.027869 · 3.53 Impact Factor