色散補償用光纖光柵之設計與製作

Abstract

本論文嘗試以「單一週期、多相位偏移光柵」（Single-period and Multi-phase-shifted FBGs）的新概念來取代啁啾型光纖光柵，設計成色散補償用的光纖元件，企圖降低其製作難度。原理在於——將整段光纖光柵適當的固定間距切割成一連串的單一週期離散光纖光柵，以相鄰取樣點間的相位差，定出二小段光纖光柵間的相位偏移量，並以「重疊步進掃描（Overlap-step-scan）」法製作，藉以降低離散誤差。

設計上，我們由訂定目標特性反射頻譜出發，經由模擬程式將設計結果轉換為實驗參數；實驗上，在經過一系列校準參數的工作以後，接著將此參數應用到實驗設備上；測量上，則應用簡單的邁克森干涉儀架構量測相位資訊。

雖然目前製作成果並不令人滿意，但已由實驗證明「單一週期、多相位偏移光柵」的設計、製作方式，確實可以達到設計目標的色散補償現象。未來將力求克服環境擾動等誤差來源，朝向穩定製作的方向邁進，並藉由這套製作方式，使得製作任意結構光纖光柵的目標得以實現。

In this thesis we try to design the FBGs for dispersion compensating with a new concept called “Single-Period and Multi-phase-shifted FBGs” instead of Chirped FBGs to decrease the fabrication difficulties. The key is to expose the FBG segment-by-segment with the same grating but with different phase shifts between the adjacent segments. The “overlap-step-scan” method is also employed in fabrication to reduce the discretized error.

In the design, we start from the targeted reflection spectrum to obtain the experimental parameters via the simulation program. In the experiment, we apply these parameters in the experimental setup after careful calibration. In the measurement, we use a Michelson interferometer to measure the grating phase information.

Although so far the experimental results are still not very satisfied, the method of design and fabrication for “single-period and multi-phase-shifted FBGs” has been demonstrated to be able to produce the targeted dispersion compensating properties. We will continue to surmount the environmental perturbations for increasing the fabrication accuracy and to realize arbitrary FBG structures by using this method.