Numerical analysis of temperature-controlled terahertz power splitter
© The Author(s) 2017
Received: 15 November 2016
Accepted: 31 March 2017
Published: 12 April 2017
As a significant terahertz functional device, terahertz beam splitters with high performance are highly required to meet the need for terahertz communication, terahertz image, and terahertz sensor systems.
The proposed 1×6 power splitter becomes 1×4 power splitter with the aid of the localized temperature change at the frequency of 1.0THz. The total output power is equivalent to 97.8% of the input power for the six-channel splitter and 95.4% for the four-channel splitter. The dimension of the device is of 35a×27a.
A temperature-controlled terahertz power divider based on photonic crystal multimode interference structure and Y-junction photonic crystal waveguides is an efficient mechanism for the power divider of terahertz waves. The proposed device paves a promising way for the realization of terahertz wave integrated device.
With the rapid development of terahertz technology, it becomes very critical and urgent to control the terahertz wave transmission efficiently. Nowadays, to manipulate the terahertz wave propagation has been one of the intensively hot research topics in both science and engineering fields. The devices for manipulation the terahertz wave include such as filters, power dividers, switches, de-multiplexers, absorbers, modulators, and so forth [1–5]. Power splitter is one key component in terahertz wave communication system, therefore, it becomes particularly important to study a terahertz power divider with high performance. In recent years, there have some research reports on the power divider in the literatures [6–12]. For example, in , C. Berry et. al. proposed a terahertz beam splitter using sub-wavelength silver grating fabricated on a high-density polymer substrate. In , C. Homes et. al. employed a thick silicon wafer as beam splitter for far-infrared and terahertz spectroscopy. In , B. Ung et. al. fabricated a terahertz beam-splitter based on low-density polyethylene plastic sheeting coated with a conducting silver layer. In  J.Li et. al. designed a terahertz wave polarization beam splitter using a cascaded multimode interference structure. In  T. Niu et. al. demonstrated a terahertz beam splitter based on periodic sub-array. For current beam splitters, there still exist some problems, such as large dimensions, the need for multilayer structures, and with non-tunable, etc. As a significant terahertz functional device, terahertz beam splitters with high performance are highly required to meet the need for terahertz communication, terahertz image, and terahertz sensor systems.
In order to be more intuitive understanding, a commercial available software module Rsoft FullWave with the finite-difference time-domain method, is employed to simulate the terahertz wave propagation in the proposed device (see Fig. 1). The perfectly matched layers are located around the designed structure as the absorbing boundary condition. The fineness of the finite-difference time-domain cells (i.e. Δx and Δy) are set as 0.05. The Δt coefficient is 0.95 and the total calculation time is 50,000. In order to excite photonic crystal waveguide mode in the device, a continuous wave source is lunched at the input port of the photonic crystal waveguide.
Results and discussions
Output power of each output port
To sum up, we have designed a temperature-controlled power splitter based on photonic crystal operating in the terahertz regime. The terahertz wave power splitter was evaluated using plane wave expansion and finite-difference time-domain method. The calculated and simulated results shows that the proposed power splitter constituted by four Y-junctions and a multi-mode interference structure with embedded localized temperature-controlled photonic crystal, which can be tuned by changing the external applied temperature. The numerical simulation results are quite consistent with the analytical predictions. The design proposed here is more amenable to fabrication and also offers greater flexibility in applications of terahertz manipulation devices.
The authors would like to thank anonymous reviewers for their valuable comments to make the paper suitable for publication.
This work was supported by the National Natural Science Foundation of China Grant No. 61379024.
YL designed and performed simulations, and analyzed data. JL performed simulations, prepared the finally drafted the manuscript and the revised manuscript. Both authors read and approved the final manuscript.
The authors declare that they have no competing interest.
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