scholarly journals Polarization-Independent Optoelectronic Modulator Based on Graphene Ridge Structure

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2559
Author(s):  
Shiliang Guo ◽  
Xin Li ◽  
Zechen Guo ◽  
Xingtao Zhao ◽  
Shuhan Meng ◽  
...  

In this paper, we propose a polarization-independent optoelectronic modulator based on the electrical absorption effect of graphene. Firstly, we use the simulation software COMSOL Multiphysics to design the structure, and find via changing the applied voltage on both ends of the graphene that the equivalent refractive index of graphene can be changed, thus changing the light absorption capacity of the modulator. The waveguides in the transverse magnetic (TM) and transverse electric (TE) modes have almost the same extinction coefficient by making a double-layer graphene ridge structure in the center of the silicon-based waveguide, which can achieve approaching modulation depth in the TM and TE modes. At 1550 nm wavelength, the two-dimensional cross-section of the structure is analyzed by the FEM method using COMSOL Multiphysics to obtain the effective refractive index of the structure. The simulation results show that when the distance between the double-layer graphene isolation layer is d = 20 nm, the TE and TM modes can achieve extinction ratios up to 110 dB over the wide communication band by selecting appropriate “ON” and “OFF” switching points. The bandwidth is 173.78 GHz and the insertion loss is only 0.0338 dB.

Nanophotonics ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 2377-2385 ◽  
Author(s):  
Zhao Cheng ◽  
Xiaolong Zhu ◽  
Michael Galili ◽  
Lars Hagedorn Frandsen ◽  
Hao Hu ◽  
...  

AbstractGraphene has been widely used in silicon-based optical modulators for its ultra-broadband light absorption and ultrafast optoelectronic response. By incorporating graphene and slow-light silicon photonic crystal waveguide (PhCW), here we propose and experimentally demonstrate a unique double-layer graphene electro-absorption modulator in telecommunication applications. The modulator exhibits a modulation depth of 0.5 dB/μm with a bandwidth of 13.6 GHz, while graphene coverage length is only 1.2 μm in simulations. We also fabricated the graphene modulator on silicon platform, and the device achieved a modulation bandwidth at 12 GHz. The proposed graphene-PhCW modulator may have potentials in the applications of on-chip interconnections.


2019 ◽  
Vol 14 (5) ◽  
pp. 515-519 ◽  
Author(s):  
Zhou Dapeng ◽  
Xiao Binggang ◽  
Xiao Lihua ◽  
Guo Fenglei ◽  
Wang Xiumin

2021 ◽  
Author(s):  
Farooq Abdulghafoor Khaleel ◽  
Shelan Khasro Tawfeeq

Abstract In this paper, a double-layer approach is proposed to design a compact four states polarization-independent grating coupler (GC). The proposed polarization-independent GC is designed to couple a 700 nm polarized light propagated in a 150 nm Gallium Phosphide (GaP) waveguide to a polarization-maintaining fiber (PMF). The double-layer approach is based on the deposition of GaP gratings designed to couple the transverse magnetic (TM) light over the GaP gratings designed to couple the transverse electric (TE) light. The two layers are separated by a Hydrogen silsesquioxane (HSQ) with an optimum thickness of 20 nm. The proposed method resulted in relatively high coupling efficiencies (CEs) of 39.2%, 31.1%, and 23.3% for the TE, TM, and 45º/-45º linearly polarized light, respectively. The polarization-dependent loss (PDL) is 1 dB, 1.26 dB, and 2.26 dB corresponds to TE-TM, TM-45º/-45º, and TE-45º/-45º, respectively. The performance of the double-layer approach is numerically verified by the two-dimensional (2D) finite element algorithm (FEM) using COMSOL software. The proposed method suggests a novel and simple approach to design a compact four states polarization-independent GC that could be used in integrated (on-chip) photonic communication circuits.


2021 ◽  
Author(s):  
Farooq Abdulghafoor Khaleel ◽  
Shelan Khasro Tawfeeq

Abstract In this paper, a double-layer approach is proposed to design a compact four states polarization-independent grating coupler (GC). The proposed polarization-independent GC is designed to couple a 700 nm polarized light propagated in a 150 nm Gallium Phosphide (GaP) waveguide to a polarization-maintaining fiber (PMF). The double-layer approach is based on the deposition of GaP gratings designed to couple the transverse magnetic (TM) light over the GaP gratings designed to couple the transverse electric (TE) light. The two layers are separated by a Hydrogen silsesquioxane (HSQ) with an optimum thickness of 20 nm. The proposed method resulted in relatively high coupling efficiencies (CEs) of 39.2%, 31.1%, and 23.3% for the TE, TM, and 45º/-45º linearly polarized light, respectively. The polarization-dependent loss (PDL) is 1 dB, 1.26 dB, and 2.26 dB corresponds to TE-TM, TM-45º/-45º, and TE-45º/-45º, respectively. The performance of the double-layer approach is numerically verified by the two-dimensional (2D) finite element algorithm (FEM) using COMSOL software. The proposed method suggests a novel and simple approach to design a compact four states polarization-independent GC that could be used in integrated (on-chip) photonic communication circuits.


2017 ◽  
Vol 137 (11) ◽  
pp. 415-416 ◽  
Author(s):  
Tomoki Shimizu ◽  
Yoshiaki Kanamori ◽  
Kazuhiro Hane

2020 ◽  
Vol 330 ◽  
pp. 01005
Author(s):  
Abderrahmane AISSA ◽  
Mohamed Amine MEDEBBER ◽  
Khaled Al-Farhany ◽  
Mohammed SAHNOUN ◽  
Ali Khaleel Kareem ◽  
...  

Natural convection of a magneto hydrodynamic nanofluid in a porous cavity in the presence of a magnetic field is investigated. The two vertical side walls are held isothermally at temperatures Th and Tc, while the horizontal walls of the outer cone are adiabatic. The governing equations obtained with the Boussinesq approximation are solved using Comsol Multiphysics finite element analysis and simulation software. Impact of Rayleigh number (Ra), Hartmann number (Ha) and nanofluid volume fraction (ϕ) are depicted. Results indicated that temperature gradient increases considerably with enhance of Ra and ϕ but it reduces with increases of Ha.


2019 ◽  
Vol 125 (7) ◽  
pp. 073104 ◽  
Author(s):  
Shahram Bahadori-Haghighi ◽  
Rahim Ghayour ◽  
Mohammad Hossein Sheikhi

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