先進分佈式回饋雷射晶片之開發應用於光通訊及光感測系統

Abstract

本論文旨在探討與實現多種先進分佈式回饋 (DFB) 雷射晶片架構，針對光通訊領域如量子加密通訊、低軌道衛星光通訊、矽光子、共封裝光學，以及光感測應用如LiDAR、太赫茲感測，提出高效能、高穩定性及緊湊尺寸的雷射解決方案。 第一章提出研究動機，介紹半導體雷射的基礎理論、DFB雷射的操作原理以及自建的半導體雷射模擬平台，用以奠定後續研究的理論基礎。 第二章成功開發出600 µm短腔1.55 µm窄線寬DFB雷射，透過strain-induced InGaAsP主動區與多階段SCH波導設計，有效壓制雷射相位噪音。實驗顯示此雷射閾值電流最低達8.7 mA，PCE高達28.5\%，輸出功率超過60 mW。在50–175 mA間可連續調諧331 GHz頻率，SMSR穩定於50 dB以上，透過長短延遲DSHI驗證本質線寬低於20 kHz，適用於量子加密通訊與低軌道衛星光通訊平台。 第三章延伸1.55 µm DFB雷射元件的應用場景，首先驗證DFB雷射奈秒脈衝操作於Eye-Safe LiDAR系統，成功達成峰值功率6.3 W、脈衝寬度20.4 ns、單脈衝能量128 nJ的高穩定輸出。DFB雷射具備優異波長穩定性，適合低成本ToF-LiDAR等戶外測距之應用。再者，針對LEO光通訊需求，雷射輸出功率達125.76 mW、最大3 dB頻寬為6.12 GHz，並能低噪音傳輸12 Gb/s NRZ訊號。此外，透過兩段Bragg光柵設計的單晶片DW-DFB雷射產生穩定0.277–0.283 THz拍頻，具備高光功率、PDM< 1 dB、SMSR超過36 dB，本質線寬分別達117.33 kHz與70.59 kHz，展現太赫茲無線通訊與感測潛力。

第四章針對AI數據中心應用設計1.31 µm短腔高功率DFB雷射，以支援CPO系統之ELSFP規格。實驗顯示於25°C時最大功率達125 mW、PCE高於36%、相對強度噪音低至-159 dB/Hz，操作溫度至105°C仍能維持20 mW以上之功率，展示其適合用於高速交換器光源模組。 第五章開發高速直接調製能力的1.31 µm DFB雷射，採AlGaInAs材料系統與優化磊晶結構，提升微分增益以及響應頻率。成功展示未冷卻條件下穩定傳輸50 Gb/s NRZ和70 Gb/s PAM-4，RIN低於-147.14 dB/Hz，並透過TDECQ數值驗證其符合IEEE 802.3bs對200G乙太網路之要求。 本論文透過半導體元件模擬、磊晶設計、元件製作與特性驗證，展示不同波長與功能之DFB雷射潛力，奠定未來緊湊尺寸、高效率、高頻寬、低雜訊、低功耗光電整合平台的技術基礎。

This dissertation explores advanced distributed feedback (DFB) laser chip architectures, presenting efficient, highly stable, and compact solutions for optical communications, including quantum encryption, LEO satellite links, silicon photonic, and co-packaged optics, as well as sensing applications such as LiDAR and terahertz sensing. Chapter 1 presents the research motivation and introduces the basic theories of semiconductor lasers, the operating principles of DFB lasers, and the self-constructed semiconductor laser simulation platform, which is used to lay the theoretical foundation for the subsequent research. Chapter 2 introduces a 600-µm short-cavity 1.55-µm DFB laser with an exceptionally low intrinsic linewidth below 20 kHz, high efficiency (PCE of 28.5%), and output power exceeding 60 mW, ideal for quantum encryption and satellite communications. Chapter 3 demonstrates the 1.55-µm laser’s versatility in LiDAR, achieving stable nanosecond pulses (peak power 6.3 W, pulse width 20.4 ns), and in terahertz applications with a monolithic dual-wavelength DFB laser generating stable THz beat frequencies (0.277–0.283 THz), high SMSR (> 36 dB), and linewidths as low as 70.59 kHz. Chapter 4 presents a 1.31-µm short-cavity, high-power DFB laser for AI data-center applications, achieving >125 mW output power, high efficiency (>36% PCE), and maintaining performance at elevated temperatures (105°C). Chapter 5 focuses on a directly modulated 1.31-µm DFB laser with optimized AlGaInAs epitaxy, enabling stable, uncooled data transmission up to 70 Gb/s PAM-4, compliant with IEEE 802.3bs standards for 200G Ethernet. Through detailed device simulations, epitaxial design, fabrication, and characterization, this thesis establishes a solid technical foundation for future compact-size, high-efficiency, high-bandwidth, low-noise, and energy-efficient integrated photonic platforms.