A Tunable Band-Stop Filter Based on Photonic Crystal

Abstract

The invention discloses a tunable band-stop filter based on photonic crystals. The filter is mainly composed of two materials with different refractive indices, a dielectric layer and a phase-change layer, which are periodically arranged and overlapped with each other. The structural dimensions are exactly the same. The principle of the filter is that when the electromagnetic wave is incident vertically along the positive direction of the Z axis, the electromagnetic wave will be reflected and refracted countless times at the interface of the stack, thus forming a very flat, near-horizontal stop band, also known as photon Forbidden. On the basis of photonic crystals, a phase-change medium is used, so that the photonic band gap of photonic crystals is blue-shifted. The biggest advantage of this filter is that it can realize the dynamic tunability of the electromagnetic characteristics of the device. While being easy and inexpensive to manufacture, stopband filtering works extremely well.

Description

technical field [0001] The invention relates to the field of electromagnetic wave filtering characteristics in the terahertz band, in particular to a tunable band-stop filter based on photonic crystals. Background technique [0002] In recent years, great attention has been paid to innovative strategies for developing devices with stable optical properties. However, with the deepening of the application of nanophotonic devices and optoelectronic devices, in terms of integrated photonic chips, optical interconnects and even photonic integrated circuits, the optical characteristics of solid-state have been out of touch with practical applications. This requires the introduction of active features into the device to increase the flexibility of dynamic adjustment, so more and more researchers have begun to pay attention to the tunable characteristics of the device. [0003] The concept of photonic crystal was proposed by S.John and E.Yablonovitch respectively in 1987, and it ha...

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Problems solved by technology

However, these schemes are difficult to achieve effective active tuning

[0005] For example, the material used in the article (Ahmed, Shaban, & Aly, 2017) is lithium niobate (LN). When it is connected to the electrode, although it can also achieve the tuning function, it uses an ultra-high bias voltage, which is in In practical application, it is a difficult problem

Another example is that the material used in the article (Phys et al., 2017) is liquid crystal. When this device is connected to electrodes, it can also achieve better tuning function, but the most important point is that the design and manufacture of liquid crystal-based layers face high Complexity and difficulty in integrating, which is against the direction of future development

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