近年來，雙折射光纖在通訊系統以及光纖感測器應用上受到相當大的矚目。在本
篇論文中，我們成功地利用選擇性封孔技術和真空吸引方法，將折射率液體以及
染料掺雜的液晶，分別選擇性地填入部份的光子晶體光纖的空氣孔洞當中，製作
了半填雙折射光子晶體光纖和中線結構的液晶光子晶體光纖。
我們首先量測了半填光子晶體光纖的彎曲損耗，得知當彎曲方向為0°方向
時，由於折射率差的挶限機制而有較小的損耗。另外，相較於全填的光子晶體光
纖，半填的結構因為減少液體填充孔洞的數量，可以得到較低的彎曲損耗。接著
我們利用了桑亞克光纖迴路(Sagnac fiber loop)來量測半填雙折射光子晶體光纖
以及中線的液晶光子晶體光纖的雙折射特性。我們得到半填光子晶體光纖的雙折
射率在波長 1411 nm 下為2.39×10^-4。此外，我們透過量測得到此半填光子晶體
光纖對溫度、張力、扭轉的敏感度分別為： -0.614 nm/°C、0.466 pm/με 和 -0.316
nm/deg。對於溫度、張力和扭轉的高敏感度顯示了此半填光子晶體光纖具有應用
在光纖感測器的能力。
另一方面，我們也量測了中線液晶光子晶體光纖在施加光線以及改變溫度下
雙折射率的變化。在外在光線施加下，我們觀察到雙折射率從2.8×10^-3 變化到
4.12×10^-3；而利用外在溫度，雙折射率變化可以從2.3×10^-3 改變到 3.3×10^-3。根
據量測結果，我們證明了此中線填充液晶光子晶體光纖之雙折射率具有光調變以
及溫度調變的能力。

Birefringent fibers have attracted considerable attention in recent years for their
potential applications in communication and sensing. In this thesis we selectively
infiltrate high-index liquids or liquid crystals (LCs) into specified air holes of the
photonic crystal fibers (PCFs) by using a selective blocking technique and the vacuum
filling method to form half-filled birefringent PCFs and central-filled liquid crystal
PCF (LCPCF).
We first measure the bending loss of the half-filled PCF. Smaller bending loss
was obtained as the PCF was bent in 0° due to the dominat index-guiding. Compared
with the full-filled PCF, the half-filled PCF possesses a smaller bending loss for the
reduction of liquid-filled air holes. The birefringent properties of the half-filled PCF
and the LCPCF were then measured in cooperation with the Sagnac fiber loop. We
can obtain the birefringence of the half-filled PCF of 2.39×10^-4 at λ = 1411 nm, and
the sensitivity to temperature, strain, and torsion can be obtained as -0.614 nm/°C,
0.466 pm/με, and -0.316 nm/deg. These large sensitivities make the half-filled PCF
useful in sensing applications.
We also measured the birefringence of the central-filled LCPCF with variant
laser irradiation and temperature. The optical and thermal birefringence variations
from 2.8×10^-3 to 4.12×10^-3 and from 2.3×10^-3 to 3.3×10^-3 can be oberserved,
respectively. The optically and thermally tunable birefringence of the central-filled
LCPCF was experimentally demonstrated.

1 Introduction 1
1.1 Polarization-maintaining Fibers ……........................1
1.2 Birefringent Photonic Crystal Fibers ……………….2
1.3 Fluid-filled PCFs ……………………………………...4
1.4 Chapter Outline ………………………………………5
2 Fabrication of Birefringent Photonic Crystal Fibers by Selective Fluid Infiltration 13
2.1 Overview …………………………………..................13
2.2 Selective Blocking Technique ……….....................13
2.3 Vacuum Filling Method …………….........................14
2.4 Birefringent Half-Filled Photonic Crystal Fiber .…15
2.5 Birefringent Central-Filled Photonic Crystal Fiber ....................................................................................16
3 Measurement of Birefringent Half-filled Photonic Crystal Fibers 28
3.1 Overview …………………………………………......28
3.2 Measurement for Bending Loss ………………….28
3.3 Sagnac Loop Interferometer .........….......................30
3.4 Measurement for Temperature Sensitivity …........35
3.5 Measurement for Strain Sensitivity ……………….36
3.6 Measurement for Torsion Sensitivity ……………..38
4 Photo-Controllable Birefringent Central-filled Photonic Crystal Fiber 58
4.1 Overview ……………………………………..............58
4.2 Liquid-Crystal-filled PCFs …………………………58
4.3 Optical Tunability of the Central-filled LCPCF …..60
4.4 Temperature Tunability of the Central-filled LCPCF.................................................................................62
5 Conclusions 72
Bibliography 74

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