費比布洛雷射二極體與摻鉺光纖放大器之互注鎖定原理與應用

Abstract

這篇論文分析了在掺鉺光纖放大器或雷射（EDFA或EDFL）中，藉由使用費比布洛雷射二極體作為超窄帶通濾波器，理論和實驗證實了互注鎖定EDFL-FPLD和EDFA-FPLD連結的側模抑制和線寬縮小。以放大迴授迴路為基礎，藉由使用自相干頻譜的分析，EDFA-FPLD連結的3-dB線寬可被量測出來為3.4 MHz。不像EDFLFPLD連結，EDFA-FPLD連結幾乎沒有拍模雜訊的干擾。這是由於在EDFA-FPLD連結中，不再形成共振腔的架構，但這會輕微地付出側模抑制比（~42 dB）下降的代價。在EDFA-FPLD連結中最大的輸出功率為20毫瓦，此時FPLD輸入功率為0.1毫瓦。 另一方面，在OC-48傳輸速率上，藉由操作注入鎖定之費比布洛二極體在小於臨界電流時，NRZ至PRZ格式轉換機制是由於NRZ訊號受到外注鎖定使得有效臨界電流下降。當外注功率為-2 dBm，外注波長匹配FPLD以及RF的驅動功率在24.4 dB時，最大的消失率為12.2 dB。在外注功率為6 dBm時，PRZ訊號有最佳的側模抑制比40 dB，最短的脈衝寬44 ps，最小的時脈擾動0.4 ps，以及載子頻率在5 kHz有相對低的相位雜訊-100 dBc/Hz。當位元誤碼率為10-9，有1.2 dB轉換功率的損失。另可藉著使用這樣NRZ至PRZ格式的轉換器，一個全光式邏輯的或閘操作可被達成。

In this thesis, the theory and experiment for side-mode suppression and linewidth reduction of mutually injection-locked EDFL-FPLD and EDFA-FPLD links are demonstrated by using Fabry-Perot laser diode (FPLD) as a resonant ultra-narrow band-pass filter in an Erbium-doped fiber amplified or laser (EDFA or EDFL). Based on the amplified feedback injection loop, the 3-dB linewidth of 3.4 MHz for the EDFA-FPLD link is determined by using self-heterodyne interferometric spectral analysis. The EDFA-FPLD link exhibits a nearly mode-beating noise free performance as compared to the EDFL-FPLD link. This is due to the release of the resonant cavity configuration in the EDFL-FPLD link at a cost of slightly lower side-mode suppression ratio (~42 dB). The maximum output power of the EFDA-FPLD link is 20 mW under an FPLD input power of 0.1 mW. On the other hand, nonreturn-to-zero (NRZ) format data is transformed into a pseudo-return-to-zero (PRZ) format data at OC-48 data rate by injection-locking an Fabry-Perot laser diode operated at below threshold condition. The mechanism of the NRZ-to-PRZ format transformer results from the reduction of the effective threshold current due to the injection locking of the incoming NRZ data. With -2 dBm, wavelength-matched power injected into the FPLD, the maximum extinction ratio of 12.2 dB was obtained at the RF driving power of 24.4 dB. The best side mode suppression ratio of 40 dB, the shortest pulsewidth of 44 ps, the lowest timing jitter of 0.4 ps, and relatively low phase noise of -100 dBc/Hz at 5 kHz offset from carrier frequency of the PRZ data under injection power of 6 dBm were also obtained. Power penalty measured at a bit-error rate of 10-9 was 1.2 dB. In applications, by using such an NRZ-to-PRZ transformer an all-optical logical OR operation is also demonstrated.