A terahertz photonic crystal fiber coupler

A photonic crystal fiber and coupler technology, which is applied in the field of terahertz transmission, can solve the problems of long length and achieve stable performance, low polarization-dependent loss, and simple fiber structure

Inactive Publication Date: 2011-12-21
JIANGSU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the length of this optical fiber is nearly 20 cm, which is too long for terahertz waves that are easily absorbed by the medium.

Method used

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  • A terahertz photonic crystal fiber coupler
  • A terahertz photonic crystal fiber coupler
  • A terahertz photonic crystal fiber coupler

Examples

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Embodiment 1

[0036] Take the outer layer air hole 2 diameter d 1 and inner air hole 3 diameter d 2 Satisfy d 1 = d 2 = d . Take the fiber parameter as: hole period Λ =240 μm, air hole diameter d =144 μm. at wavelength lambda =300 μm, get its x The polarized coupling length is 1.968 cm, y The polarized coupling length is 2.193 cm. Pick x The coupling length of the polarization is the length of the fiber coupler, so the curve of the bandwidth of the coupler changing with the wavelength is obtained as Figure 8 shown. Under the premise that the insertion loss is required to be less than 3.4 dB, the bandwidth range of this coupler can be obtained from 295 to 330 μm, and the bandwidth is 35 μm. by x Polarization is used as an example to illustrate the size of the output energy of the coupler. The calculated absorption loss is 2.558 dB, plus the insertion loss of 3 dB through the coupler, the output energy is 5.558 dB. After conversion, the output energy of the single-sided ...

Embodiment 2

[0038] Take the outer layer air hole 2 diameter d 1 and inner air hole 3 diameter d 2 Satisfy d 1 > d 2 . The air hole period is Λ =200 μm, the normalized diameter of outer air pores d 1 / Λ =0.85, the normalized diameter of the air hole in the inner layer d 2 / Λ= 0.45, i.e. d 1 =170 μm, d 2 =90 μm. At this time, the fiber x The coupling length of the polarization mode is 0.636 cm, y The polarization mode is 0.653 cm. because fiber x with y The coupling length difference of polarization is very small, so the length of the fiber is taken asx Polarized coupling length, its bandwidth change curve is as follows Figure 9 shown. As shown in the figure, when the wavelength is in the range of 285-325 μm, the insertion loss of the coupler is less than 3.4 dB, and the bandwidth is 40 μm. by x Taking polarization as an example, it can be concluded that at the central wavelength of 300 μm, the output energy of the output terminal on one side is 41.43% of the t...

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Abstract

The invention discloses a terahertz photonic crystal fiber coupler. Including cladding and core, the core is three, surrounded by the inner air hole (3) at the apex of the regular hexagon, wherein the first core (4) is formed by the center of the matrix material (1) , the second core (5) and the third core (6) are symmetrically located on both sides of the first core (4); the network of outer air holes (2) is located around the inner air holes, and the adjacent holes are equally spaced; the first fiber core (4) is the input end, the second fiber core (5) and the third fiber core (6) are the output ends; the inner air hole (3) Same as the hole period Λ of the outer layer air holes (2), the relationship between the diameter d1 of the outer layer air holes (2) and the diameter d2 of the inner layer air holes (3) satisfies d1≥d2. The invention has the advantages of working in a wide wavelength range, stable output, low transmission loss and polarization-dependent loss, and the like.

Description

technical field [0001] The invention relates to terahertz transmission technology, in particular to a terahertz coupler based on an optical fiber structure. Background technique [0002] Terahertz (THz for short) waves are located between the microwave and infrared bands in the electromagnetic spectrum, and refer to electromagnetic waves with a frequency in the range of 0.1-10 THz (wavelength 30-3000 μm) (1 THz=10 12 Hz). Terahertz waves play an important role in high data rate communications, spectroscopy applications, medical and biological detection, etc. Terahertz waves are easily absorbed by dielectric materials, such as polymethyl methacrylate (PMMA) with an absorption loss of 4.3 cm at 0.5 THz -1 ; The absorption loss of high-density polyethylene (HDPE) in the 0.1-3THz band is less than 1 cm -1 , better than polymethyl methacrylate; and polytetrafluoroethylene (Teflon), which has a lower absorption loss, still has an absorption loss of 0.3 cm at 1 THz (that is, a ...

Claims

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Application Information

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IPC IPC(8): G02B6/036
Inventor 陈明阳付晓霞张永康
Owner JIANGSU UNIV
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