利用反射式光放大器建構雙向次載波多工傳輸系統

Bidirectional Subcarrier Multiplexing Transport Systems Based on RSOA

陳楷仁(Kai-Jen Chen)

指導教授 ： 呂海涵

國立臺北科技大學/電資學院/光電工程系研究所/碩士(2010年)

摘要

在此篇論文中，利用反射式光放大器建構完成一雙向的傳輸系統，長距離被動光纖網路的傳輸系統可以有效降低早期被動光纖網路的傳輸成本，光反射式放大器可放大雷射光強度，並且可以載送信號，達成雙向傳輸系統。
首先我們將反射式半導體光放大器置於用戶端，再將下行的CATV訊號載入CATV外部調變機，藉此CATV信號得以載入光纖。光信號經由光放大器傳送，頭端至節點的傳送距離為60公里單模光纖後，進入用戶端的CATV光接收器做訊號處理，即可量測載波雜訊比(CNR)、載波二次合成拍差比(CSO)與載波三次合成拍差比(CTB)。
之後光的訊號藉由反射式光放大器做上行傳輸，訊號直接調變至反射式半導體光放大器，載入的訊號有正交分頻多工訊號和假隨機二位元序列訊號，上行的光信號經過光放大器後，傳送60公里的單模光纖並進入頭端的光接收器。此傳輸系統在下行訊號方面，可以得到良好的載波雜訊比(CNR)、載波二次合成拍差比(CSO)與載波三次合成拍差比(CTB)，上行訊號也可滿足無錯的要求。

關鍵字

光纖有線電視 ； 正交分頻多工 ； 光纖微波 ； 反射式光放大器 ； 次載波多工

並列摘要

In this thesis, a bidirectional CATV/radio-on-fiber (ROF) long reach transport system based on reflective semiconductor optical amplifier (RSOA) is proposed and demonstrated. Transmission performances over 60 km of standard single mode fiber (SMF) were investigated. System downstream performances evaluated by carrier-to-noise ratio (CNR), composite second order (CSO), composite triple beat (CTB) and upstream performance evaluated by bit error rate (BER).
Directly modulated RSOA with orthogonal frequency division multiplexing (OFDM) – quadrature amplitude modulation (QAM) signal and non-return-to-zero (NRZ) with pseudo random binary sequence (PRBS) were proposed and demonstrated. OFDM signal efficiently increases the data rate of transport system. Good performances of CNR, CSO, CTB and error-free were achieved for a 60 km bidirectional SMF transmission.

並列關鍵字

Fiber-optical CATV ； orthogonal frequency division multiplexing ； radio-on-fiber ； reflective semiconductor optical amplifier ； subcarrier multiplexing

參考文獻

[1] H. H. Lu, H. L. Ma, Y. W. Chuang, Y. C. Chi, C. W. Liao and H. C. Peng, “Employing injection-locked Fabry-Perot laser diodes to improve bidirectional WDM-PON performances,” Opt. Commun., vol. 270, pp. 211-216, 2007.

[2] C. Desem, “Composite second order distortion due to self-phase modulation in externally modulated optical AM-SCM systems operating at 1550 nm,” Electron. Lett., vol. 33, pp. 2055-2056, 1994.

[3] R. P. Davey, D. Nesset, A. Rafel, D.B. payne and A. Hill, “Designing long reach optical access networks,” BT Technology Journal, vol. 24, pp. 13-18, 2006.

[4] C. S. Choi, H. S. Kang, W. Y. Choi, D. H. Kim and K. S. Seo, “Phototransistors based on InP HEMTs and their applications to millimeter-wave radio-on-fiber systems,” IEEE Trans. Microw. Theory Tech., vol. 53, pp. 256-263, 2005.

[5] H. Ku and J. S. Kenney, “Estimation of error vector magnitude using two-tone intermodulation distortion measurements,” in IEEE MTT-S Int. Microw. Symp. Digest, vol. 1, pp. 17-20, 2001.