Triplexer based on heterojunction photonic crystal coupler waveguide

Abstract

The invention discloses a triplexer based on a heterojunction photonic crystal coupler waveguide. The triplexer comprises a first photonic crystal unit and a second photonic crystal unit connected with each other, the first photonic crystal unit is provided with a main waveguide and two lower waveguides, the two lower waveguides are respectively located at two sides of the main waveguide, the axesof the two lower waveguides are overlapped and vertical to the axis of the main waveguide, the second photonic crystal unit is provided with an upper waveguide, the axis of the upper waveguide and the axis of the main waveguide are overlapped, a coupling micro-cavity is respectively arranged between the main waveguide and the two lower waveguides and between the main waveguide and the upper waveguide, and passive silicon defect dielectric cylinders are respectively arranged in the three coupling micro-cavities. According to the triplexer, multichannel filtering is realized by employing heterojunction type photonic crystal materials; and through adjustment of the radiuses and the deviation amounts of the passive silicon defect dielectric cylinders in the two micro-cavities, the transmittance is improved, the insertion loss is reduced, and the target light wave transmittance is increased.

Description

technical field [0001] The invention relates to a single-fiber three-way optical device, in particular to a single-fiber three-way optical device based on a heterojunction photonic crystal coupling cavity waveguide. Background technique [0002] With the increasing demand for bandwidth of data services, traditional optical devices can no longer meet the high-speed development of communication networks. In modern optical communication systems, the single-fiber three-way optical device is a core device of PON FTTH. Its performance directly affects the quality of communication. Its main function is to transmit analog CATV signals with a wavelength of 1550nm and digital signals with a wavelength of 1490nm. Coupled with the terminal user transmission signal with a wavelength of 1310nm into one optical fiber, so as to realize the "three-network integration" service. [0003] At present, single-fiber three-way optical devices in practical applications are coupled by discrete compo...

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Problems solved by technology

However, there are few reports on multi-channel drop filters based on photonic crystals. The wavelengths that can be operated are generally relatively single, the structure is relatively complex, and there is still a certain loss in the communication band, which indirectly reduces the transmission of the required light waves. The specific defects are as follows:

[0006] 1. Traditional single-fiber three-way optical devices are coupled by discrete components. The integration level is relatively low, and errors are prone to occur in the processing process, thereby reducing the coupling efficiency and causing serious losses. The device packaging is difficult and the production efficiency is low. , there are problems such as the filter is easy to scratch, the scrap rate and cost are high, and it is not suitable for the development of photonic integration in the future;

[0007] 2. Due to the unreasonable design of material parameters such as the dielectric constant ratio, lattice structure, and medium filling ratio of different media, the photonic band gap is narrow, and the corresponding wavelength λ range partially meets the communication band range, making the filtering frequency band relatively single , cannot meet the requirements of the multiplexing system;

[0008] 3. The overall structural design of the microcavity and the coupling with the waveguide will easily cause the loss of part of the light wave energy. There is a filter design scheme based on the photonic crystal microring structure, which has a complex structure, and this structure is easy to excite at the corner of the ring area. Other modes, thus reducing the efficiency of the drop filter, increasing the loss, and reducing the transmittance

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