摘要
本論文介紹以蚊子法(mosquito method)製成之漸變式折射率高分子聚合物光波導設計4通道 × 25-Gbps單模光學連接收發模組之光學系統。本系統整合了雷射驅動晶片、轉組放大晶片、分散式回饋雷射與光檢測器於陶瓷基板，並覆晶封裝於印刷電路板，且以主動式對位法連接光學主動元件與高分子聚合物波導，再以PMT connector連接高分子聚合物波導與單模光纖。
本高分子聚合物波導之設計，包含漸變折射率圓柱波導、對單模光纖耦合之波導橢球結構、主被動元件間距匹配彎曲波導結構、45度微反射面與圓拱形波導截面聚光結構等，藉此達到設計適用於遠距離傳輸之單模光學連接收發模組。
此設計之光學模擬結果為:發射端之4通道平均光學插入損耗 3.30 dB，接收端之光學插入損耗 1.50 dB，由發射端到接收端之4通道平均總光學插入損耗 4.80 dB。光學主動元件在錯位損耗增加 1 dB情況下，在光軸上平均錯位容忍度為4微米(遠離波導)，非光軸上平均錯位容忍度為±4.2微米，單模光纖光軸上錯位容忍度大於+20微米(遠離波導)，非光軸上錯位容忍度為±2.1微米。由上述可知主動式封裝之精準度滿足此設計之要求。
;Abstract
The design of the optical system for 4-channel × 25-Gbps single-mode optical interconnect module based on mosquito-method-made graded-index polymer optical waveguide is proposed. The diver IC, transimpedance amplifier (TIA), DFB lasers, and photodetectors were integrated on the ceramic substrate, which was flip-chip mounted on the printed circuit board. The DFB lasers/photodetectors, and polymer waveguide were connected by active alignment process. Furthermore, PMT connector was using to connect the polymer waveguide with the single-mode fiber (SMF).
The graded-index circular single-mode waveguide (GI-CSMWG) design of single-mode optical interconnect module include the ellipsoid structure for WG-SMF coupling, the bending waveguide for separation-matching, and the 45° micro-reflector with cambered-surface focusing design of core. These designs of the single-mode optical interconnect module made longer transmission distance.
The optical simulation result of optical insertion loss for transmitting part is -3.30 dB, for receiving part is -1.50 dB, and for whole optical interconnect module is -4.80 dB. The average 1-dB optical-axis-parallel alignment tolerances of DFB laser and photodetector are ±4 micron, and optical-axis-perpendicular part are ±4.2 micron. The 1-dB optical-axis-parallel alignment tolerance of SMF is more than +20 micron (to be remove from WG), and optical-axis-perpendicular part is ±2.1 micron. As a result, the design can meet the variability of the active alignment process.
