Optical waveguide switch

Abstract

Techniques are described to form an optical waveguide switch that could reach a very high extinction ratio. In particular, this disclosure describes an asymmetric MZI, in which different waveguide capacitor structures are used in two arms of the MZI: a first arm with a waveguide capacitor to achieve the mainly phase modulation and a second arm with a waveguide capacitor to achieve mainly the magnitude modulation, respectively. Using the asymmetric MZI in accordance with this disclosure, one can design an algorithm to achieve almost unlimited extinction ration during the switching operation.

Description

technical field [0001] The invention relates to an optical waveguide switch, in particular to an optical waveguide switch adopting an MZI structure. Background technique [0002] It is a common technique to construct an optical waveguide switch or modulator using a Mach-Zehnder interferometer (MZI) structure. In US Pat. No. 7,817,881, the concept of a waveguide container is introduced. Free carriers can be stored in the waveguide core of this waveguide container to modulate the refractive index of the waveguide material. [0003] In silicon photonics, the free carrier dispersion effect is applied to modulate the refractive index of silicon, so MZI structures can be used to form switches or amplitude modulators. However, in the free carrier dispersion effect, the injected free carriers can affect not only the real part of the refractive index, but also the imaginary part of the refractive index, that is, it will cause light attenuation while modulating the phase. Due to the...

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Problems solved by technology

However, in the free-carrier dispersion effect, the injected free carriers can affect not only the real part of the refractive index but also the imaginary part of the refractive index, i.e., it causes attenuation of light while modulating the phase

Due to the difference in optical power when the beams output by the two arms of the MZI interfere, the optical switch composed of the MZI cannot achieve a very high extinction ratio.

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