Photonic crystal fiber directional coupler

Abstract

The invention discloses a photonic crystal fiber directional coupler. Host material (1), holes (2) and holes (3) form fiber cores and a cladding, wherein the holes (2) and the holes (3) are formed in the host material (1). Centers of the holes (2) and the holes (3) are respectively located on nodes of a right triangle structured grid. The number of the fiber cores is three, where the first fiber core (4) is arranged on a center area of the host material (1), the right triangle structured grid misses a hole to from the first fiber core (4), the second fiber core (5) and the third fiber core (6) are symmetrically located on two sides of the first fiber core (4), the right triangle structured grid respectively misses a hole to from the fiber core (5) and the fiber core (6), air holes around innermost layers of the fiber core (5) and the fiber core (6) are the holes (2) and the holes (3), and the relationship of the diameter d2 of the holes (3) and the diameter d1 of the holes (2) satisfies that d2 >=d1. According to the photonic crystal fiber directional coupler, the diameters of the cladding air holes (3) of the fiber cores (the fiber core (5) and the fiber core (6)) on two sides are changed, and the advantages of being wide in wavelength coverage operation, insensitive to the fiber length and low in transmission loss and polarization relevant loss and other advantages are achieved.

Description

technical field [0001] The invention relates to the technical fields of optical fiber communication and sensing, and in particular to a photonic crystal fiber directional coupler. Background technique [0002] Optical fiber and optical waveguide directional coupler, as an important optical device, is widely used in optical fiber communication, cable TV network, subscriber loop system, area network and other systems. Although there are a variety of 1×2 beam splitting devices based on Y-shaped or T-shaped structures, due to their low transmittance, an additional fine-tuning structure needs to be introduced to improve the transmittance of the beam splitter, so as to give this type of light The manufacture of beam splitters poses difficulties. In recent years, with the introduction of photonic crystal fiber (PCF), especially because of its structural design flexibility and other characteristics, it has been widely studied. Photonic crystal fiber is a new type of optical wavegu...

AI Technical Summary

Problems solved by technology

However, directional couplers that divide the energy into three with this three-core structure are rarely reported.

The main reason is that it is difficult to achieve an energy ratio of 1:1:1 (4.7 dB) in the three cores in a relatively wide operating wavelength range

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