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Prakash S R, Kumar R, Mitra A. Reconfigurable and spectrally switchable perfect absorber based on a phase-change material. APPLIED OPTICS 2022; 61:2888-2897. [PMID: 35471366 DOI: 10.1364/ao.451285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
In this paper, we propose a lithography-free spectrally tunable prefect absorber based on an asymmetric Fabry-Perot cavity using Ge2Sb2Te5 (GST), a phase-change material, as the cavity layer. The proposed device shows a maximum absorption of 99.7% at 1550 nm, at a particular angle of incidence and polarization when the phase of GST is in the amorphous state. The absorption spectrum is spectrally switched to longer wavelength when the phase of GST is transformed from amorphous to crystalline. The tuning range is about 866 nm, and the maximum absorption is maintained above 99% in the whole tuning range. The crystallinity ratio of GST is varied by applying voltage pulses of different amplitudes and durations. The electrothermal cosimulations show that the phase change is obtained in the whole GST layer. Furthermore, by reamorphization of GST, the absorption spectrum can be switched back, enabling a reconfigurable perfect absorber. This work shows a viable path toward achieving a tunable perfect absorber covering a 1550 nm communication wavelength window as well as an emerging optical communication window around 2 µm wavelength.
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Abstract
In this work, we have proposed and designed a 1 × 1 optical switch based on the optical phase-change material, Ge2Sb2Se4Te1 (GSST), for GSST-assisted silicon racetrack microring. Its optical power can periodically be exchanged between the straight silicon waveguide and the GSST/Si hybrid racetrack waveguide due to the formed directional coupling structure. By changing GSST from the crystalline state to the amorphous state, the switch shifts from the ON state to the OFF state, and vice versa. With finite-difference time-domain method optimization, the proposed switch shows an extinction ratio of 18 dB at 1547.4 nm. The insert losses at the ON and OFF states are both less than 1 dB. The proposed switch unit has the potential to build an N × N switch matrix.
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Li Y, Liu FR, Han G, Chen QY, Zhang YZ, Xie XX, Zhang LL, Lian YB. Design of an electric-driven nonvolatile low-energy-consumption phase change optical switch. NANOTECHNOLOGY 2021; 32:405201. [PMID: 34171853 DOI: 10.1088/1361-6528/ac0ead] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
Traditional optical switches relying on the weak, volatile thermo-optic or electro-optic effects of Si or SiN waveguides show a high consumption and large footprint. In this paper, we reported an electric-driven phase change optical switch consisting of a Si waveguide, Ge2Sb2Te5(GST) thin film and graphene heater suitable for large-scale integration and high-speed switching. The reversible transition between the amorphous and crystalline states was achieved by applying two different voltage pulses of 1.4 V (SET) and 4 V (RESET). The optical performance of the proposed switch showed a high extinction ration of 44-46 dB in a wide spectral range (1525-1575 nm), an effective index variation of Δneff = 0.49 and a mode loss variation of Δα = 15 dBμm-1at the wavelength of 1550 nm. In thermal simulations, thanks to the ultra-high thermal conductivity of graphene, the proposed switch showed that the consumption for the SET process was only 3.528 pJ with a 1.4 V pulse of 5 ns, while a 4 V pulse of 1.5 ns was needed for RESET process with a consumption of 1.05 nJ. Our work is helpful to analyze the thermal-conduction phase transition process of on-chip phase change optical switches, and the design of the low-energy-consumption switch is conducive to the integrated application of photonic chips.
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Affiliation(s)
- Y Li
- Key Laboratory of Trans-scale Laser Manufacturing (Beijing University of Technology), Ministry of Education, Beijing 100124, People's Republic of China
- Beijing Engineering Research Center of Laser Technology, Beijing University of Technology, Beijing 100124, People's Republic of China
- Institute of Laser Engineering, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, People's Republic of China
| | - F R Liu
- Key Laboratory of Trans-scale Laser Manufacturing (Beijing University of Technology), Ministry of Education, Beijing 100124, People's Republic of China
- Beijing Engineering Research Center of Laser Technology, Beijing University of Technology, Beijing 100124, People's Republic of China
- Institute of Laser Engineering, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, People's Republic of China
| | - G Han
- Key Laboratory of Trans-scale Laser Manufacturing (Beijing University of Technology), Ministry of Education, Beijing 100124, People's Republic of China
- Beijing Engineering Research Center of Laser Technology, Beijing University of Technology, Beijing 100124, People's Republic of China
- Institute of Laser Engineering, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, People's Republic of China
| | - Q Y Chen
- Key Laboratory of Trans-scale Laser Manufacturing (Beijing University of Technology), Ministry of Education, Beijing 100124, People's Republic of China
- Beijing Engineering Research Center of Laser Technology, Beijing University of Technology, Beijing 100124, People's Republic of China
- Institute of Laser Engineering, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, People's Republic of China
| | - Y Z Zhang
- Key Laboratory of Trans-scale Laser Manufacturing (Beijing University of Technology), Ministry of Education, Beijing 100124, People's Republic of China
- Beijing Engineering Research Center of Laser Technology, Beijing University of Technology, Beijing 100124, People's Republic of China
- Institute of Laser Engineering, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, People's Republic of China
| | - X X Xie
- Key Laboratory of Trans-scale Laser Manufacturing (Beijing University of Technology), Ministry of Education, Beijing 100124, People's Republic of China
- Beijing Engineering Research Center of Laser Technology, Beijing University of Technology, Beijing 100124, People's Republic of China
- Institute of Laser Engineering, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, People's Republic of China
| | - L L Zhang
- Key Laboratory of Trans-scale Laser Manufacturing (Beijing University of Technology), Ministry of Education, Beijing 100124, People's Republic of China
- Beijing Engineering Research Center of Laser Technology, Beijing University of Technology, Beijing 100124, People's Republic of China
- Institute of Laser Engineering, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, People's Republic of China
| | - Y B Lian
- Key Laboratory of Trans-scale Laser Manufacturing (Beijing University of Technology), Ministry of Education, Beijing 100124, People's Republic of China
- Beijing Engineering Research Center of Laser Technology, Beijing University of Technology, Beijing 100124, People's Republic of China
- Institute of Laser Engineering, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, People's Republic of China
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Ali N, Panepucci RR, Xie Y, Dai D, Kumar R. Electrically controlled 1 × 2 tunable switch using a phase change material embedded silicon microring. APPLIED OPTICS 2021; 60:3559-3568. [PMID: 33983284 DOI: 10.1364/ao.418358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
Phase change material Ge2Sb2Te5 (GST) has recently emerged as a highly promising candidate for photonic device applications owing to its high optical contrast, self-holding bi-stability, and fast material response. Here, we propose and analyze a 1×2 tunable switch using a GST embedded silicon microring resonator exploiting high optical contrast during GST phase change and a high thermo-optic coefficient of amorphous phase GST. Our device exhibits high extinction ratios of 25.57 dB and 18.75 dB at through and drop ports, respectively, with just a 1 µm long GST layer. The two states of the switch are realizable by electrically inducing phase change in GST. For post phase change from amorphous to crystalline and vice versa, the fall time down the 80% of phase transition temperature is ∼66ns and ∼45ns, respectively. The resonance wavelength shift per unit active length is 0.661 nm/µm, and the tuning efficiency is 1.16 nm/mW. The large wavelength tunability (4.63 nm) of the proposed switch makes it an attractive option for reconfigurable photonic integrated circuits.
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Liu X, Liu D, Dai D. Silicon polarization beam splitter at the 2 μm wavelength band by using a bent directional coupler assisted with a nano-slot waveguide. OPTICS EXPRESS 2021; 29:2720-2726. [PMID: 33726463 DOI: 10.1364/oe.403932] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 09/17/2020] [Indexed: 06/12/2023]
Abstract
A silicon-based polarizing beam splitter (PBS) working at the 2 μm wavelength band is proposed and demonstrated experimentally by using a bent directional coupler assisted with a nano-slot waveguide. The nano-slot width is chosen as 180 nm so that the present PBS can be fabricated with MPW foundries. In theory, the designed PBS has extinction ratios (ERs) of >15 dB and >30 dB for TM- and TE- polarizations in the wavelength range of 1825-2020 nm, respectively. For the fabricated PBS, the excess losses (ELs) are low (∼0.5 dB) while the measured results show the ERs are >15 dB and >20 dB for TM- and TE-polarizations in the wavelength band of 1860-1980 nm.
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