兩段式分佈回饋型雷射之射頻動態行為與參數提取

Abstract

我們在單片的兩段式分佈回饋雷射中嵌入6.5對的布拉格光柵做為共振腔的反射鏡，藉由獨立調變主要雷射跟從屬雷射的波長，可以產生四波混合現象並且達到產生可調變的微波訊號。組合不同的主要雷射跟從屬雷射電流可以產生不同的操作模態，例如：單模態、多模態、周期一、周期二和混亂態。當將主要雷射跟從屬雷射的注入電流以每2mA為間距個別由16mA調變至80mA互相結合，並藉由光頻譜分析儀與電頻譜分析儀記錄微波訊號，如此可以得到一個33×33的訊號動態行為圖。量測到的單模訊號頻率分佈可以從15GHz到50GHz，50GHz是光子偵測器可操作的最高頻率，但透過計算光頻譜量測值，單模頻率最高可達70GHz。藉由分析比例方程式與頻譜數據可以擬合得到雷射內部的重要參數，此種方法可達到非破壞性的量測。藉由全區域操作圖，可以在原件上找到合適的組合電流來應用在適合的地方。

We embedded the 6.5 pair’s distributed Bragg grating which substitutes for reflector in cavity into monolithic two-section distributed feedback laser. By independent modulation wavelength of master and slave lasers, the phenomenon of four-wave-mixing can be generated and the chip can generate tunable microwave signal which correspond the FWM. The combination of different driving currents for master and slave lasers can generate a wide range of different operational modes such as signal mode, multimode, period one, period two and chaos mode. When the driving current are turned from 16mA to 80mA with 2mA in each laser and the signal is recorded by optical and electrical spectrum analyses, the dynamic behavior of microwave signal can be mapped by 33×33 mesh. The frequency of detected single mode signal can continuously cover from 15GHz to 50GHz, limited by photodetector bandwidth. The measured optical four-wave-mixing pattern indicates that a 70GHz signal can be generated by this device. By analyzing the rate equation and fitting the spectrum data, the important laser internal parameters can be extracted. This method can be reached non-destructive measurement. With the full operational map at hand, the suitable current combination can be applied to the device for proper applications.