隨著各式網路需求快速的發展，例如高速商業網路、光纖到家或是光纖與無線通訊整合應用，光纖通訊流量需求逐年快速成長。在各種光學擷取網路技術中，因為成本的考量，目前以被動光學網路被最多研究團隊重視與討論。而為了滿足快速成長的網路需求，正交分頻多工技術也開始被考慮為下一世代被動光學網路的調變格式。
為了提升被動光學網路的系統表現，例如傳輸速度、誤碼率或是成本效益等，大多數的研究團隊都專注在中央機房傳輸設計或是用戶端的接收設計。因此，各種光學的調變與接收機制被提出來討論；然而，為了增加系統表現而更改用戶端的設計，往往伴隨著巨大的建置成本。在本論文研究中，我們提出了二個升級模組的概念：第一個是在遠端遙控端，我們透過簡單的被動光學原件，可以達到加倍通道的傳輸量以及用戶數的偏振態解多工模組；另一個是，透過空間路由的方式解決反向散射干擾的升級模組。兩個被提出的架構都不需要更動用戶端的設計，同時可以與分波多工系統相容；也因此可以提供系統供應商一個可以依照其市場需求的升級方案。
最後一個研究計畫是能均一化用戶下傳表現的強度調變系統。由於雙邊帶的訊號在傳輸後會受到射頻衰減的問題；不同頻率、不同接收位置的用戶也因此會有不同的訊號表現。然而，這樣不公平的接收表現不利於一般的商業模型。在本論文中，首次提出利用多載波分碼多址的調變格式來使0-100公里中各個使用者能有接近的接收表現。此外多載波分碼多址不僅與正交分頻多工擁有相同的通道容量與頻譜效益，其接收表現還可以透過數位演算法的方式進行進一步的提升，以獲得更好的系統功率預算值。

As the fast soaring of modern applications, e.g. high speed business networks, fiber to the home or fiber-wireless integration, the data rate requirement rapidly increases with the years in optical access networks. Due to its cost-effective nature, passive optical network (PON) attracts lots of attention by researchers. Meanwhile, to meet the future data rate requirement, orthogonal frequency division multiplexing (OFDM) is widely investigated and considering as one of the candidate signal formats for next generation PONs.
To enhance the performance of PON systems, including channel capacity, bit-error rate (BER) performance, and cost-effectiveness or so on, most of researchers focus on the transmitter design in the central office (CO) or the receiver design at optical network units (ONUs). Therefore, lots of modulation formats and/or receiving mechanisms are proposed for future requirements. However, enhancing the performance via modifying ONUs’ design always requires huge capital expenditures (CAPEX). In this dissertation, we propose two upgrade module concepts. First, in the powered remote node (RN), we can double the channel capacity and user numbers by passive optical polarization de-multiplexing implementation. The other one is a back propagation mitigation function by spatial routing. Both of them are highly compatible with existing wavelength division multiplexing (WDM) PON without any modification of ONUs’ design. System vendors can therefore upgrade the system depending on their marketing targets.
In the final chapter, an intensity modulation direct detection (IMDD) system is proposed with uniform downstream receiving performance among subscribers. In general, due to the double side band nature of IM signals, distinct users among different subcarrier in different locations will receive different BER performance caused by radio frequency fading loss. However, it is harmful to ordinary business model. Thus, we propose a multicarrier code division multiple access (MC-CDMA) signal format to uniform BER performance among subscribers ranging from 0 to 100 km. Moreover, the MC-CDMA signals’ performance can be further enhanced by appropriate digital signal processing. Therefore, power budget, which is typically limited by the worst user case, of the proposed MC-CDMA PON is improved with respect to the IMDD OFDM-PON.

[1] I. P. Kaminow, T. Li, and A. E. Willner, Optical Fiber Telecommunications VIB, 6th ed. (Academic, 2013), Chap. 22.
[2] J.-H. Yan, Y.-W. Chen, K.-H. Shen, and K.-M. Feng, “An experimental demonstration for carrier reused bidirectional PON system with adaptive modulation DDO-OFDM downstream and QPSK upstream signals,” Opt. Exp., vol. 21, no. 23, pp. 28154-28166, Nov. 2013.
[3] Y.-W. Chen, J.-H. Yan, K.-P. Huang, and K.-M. Feng, “A Carrier Centralized Hybrid Long Reach PON with DDO-OFDM Downstream and Nyquist-WDM Upstream,” in Proc. CLEO, San Jose, CA, 2014, paper STu1J.3.
[4] Y.-W. Chen, C.-Y. Tseng, S.-J. Liu, and K.-M. Feng, “PDM DDO-OFDM with Self-Polarization Diversity for the Backhaul of Radio-over-Fiber System,” in Proc. OFC, 2016, paper Th4A.2.
[5] Y.-W. Chen, Y.-T. Liao, T.-N. Lai, M.-F. Chang and K.-M. Feng, “Power Budget Enhancement in an IMDD PON Downstream with Multicarrier Code Division Multiple Access,” in Proc. CLEO, San Jose, CA, 2016, paper JTh2A.120.
[6] Y.-W. Chen, J.-H. Yan, Y.-M. Wang, M.-F. Chang, and K.-M. Feng, “Back Propagation Isolation Design in a Carrier Centralization WDM IFoF Fiber-Wireless Convergence,” in Proc. CLEO, San Jose, CA, 2016, paper STh1F.4.
[7] Y.-W. Chen, Y.-T. Liao, and K.-M. Feng, “Experimental demonstration of Asynchronous PON Upstream via Multicarrier Code Division Multiple Access,” in Proc. CLEO, San Jose, CA, 2016, paper SF2F.2.
[8] D.-Z. Hsu, C.-C. Wei, H.-Yu Chen, W.-Y. Li, and J. Chen, “Cost-effective 33-Gbps intensity modulation direct detection multi-band OFDM LR-PON system employing a 10-GHz-based transceiver,” Opt. Exp., vol. 19, no. 18, pp. 17546-17556, Aug. 2011.
[9] K. Kanonakis, I. Tomkos, T. Pfeiffer, J. Prat, and P. Kourtessis, “ACCORDANCE: A Novel OFDMA-PON Paradigm for Ultra-High Capacity Converged Wireline-Wireless Access Networks,” in Proc. ICTON, Munich, 2010, paper Tu.A1.2.
[10] N. Cvijetic, A. Tanaka, P. N. Ji, K. Sethuraman, S. Murakami, and T. Wang, “SDN and OpenFlow for Dynamic Flex-Grid Optical Access and Aggregation Networks,” J. Lightw. Technol., vol. 32, no. 4, pp. 864-870, Feb. 2014.
[11] Y. Takushima, K. Y. Cho, and Y. C. Chung, “Design Issues in RSOA-based WDM PON,” in Proc. IPGC, Singapore, 2008.
[12] G. de Valicourt, D. Maké, J. Landreau, M. Lamponi, G. H. Duan, P. Chanclou, and R. Brenot, “High Gain (30 dB) and High Saturation Power (11 dBm) RSOA Devices as Colorless ONU Sources in Long-Reach Hybrid WDM/TDM-PON Architecture,” IEEE Photon. Technol. Lett., vol. 22, no. 3, pp. 191-193, Feb. 2010.
[13] C. W. Chow, C. H. Yeh, L. Xu, and H. K. Tsang, “Rayleigh Backscattering Mitigation Using Wavelength Splitting for Heterogeneous Optical Wired and Wireless Access,” IEEE Photon. Technol. Lett., vol. 22, no. 17, pp. 1294-1296, Sep. 2010.
[14] S.-C. Lin, S.-L. Lee, H.-H. Lin, G. Keiser, and R. J. Ram, “Cross-Seeding Schemes for WDM-Based Next-Generation Optical Access Networks,” J. Lightw. Technol., vol. 29, no. 24, pp. 3727-3736, Dec. 2011.
[15] H.-H. Lin, C.-Y. Lee, S.-C. Lin, S.-L. Lee, and G. Keiser, “WDM-PON Systems Using Cross-Remodulation to Double Network Capacity with Reduced Rayleigh Scattering Effects,” in Proc. OFC/NFOEC, San Diego, CA, 2008, paper OTuH6.
[16] Z. Zhou, S. Xiao, T. Qi, P. Li, M. Bi, and W. Hu, “25-GHz-Spaced DWDM-PON With Mitigated Rayleigh Backscattering and Back-Reflection Effects,” IEEE Photon. J., vol. 5, no.4, Aug. 2013.
[17] S. Gosselin, A. Pizzinat, X. Grall, D. Breuer, E. Bogenfeld, S. Krauß, J. Alfonso T. Gijón, A. Hamidian, N. Fonseca, and B. Skubic, “Fixed and Mobile Convergence: Which Role for Optical Networks?,” IEEE J. Opt. Commun. Netw., vol. 7, no. 11, pp. 1075-1083, Nov. 2015.
[18] Y.-W. Chen, J.-H. Yan, Y.-M. Wang, M.-F. Chang, W.-R. Peng, and K.-M. Feng, "Over 210 Gb/s PDM multiband DDO-OFDM LR-PON downstream with simple self-polarization diversity," Opt. Exp., vol. 23, no. 14, pp. 18525-18533, Jul. 2015.
[19] S. M. Zafi, S. Shah, A. W. Umrani, and A. A. Memon, “Performance comparison of OFDM, MC-CDMA and OFCDM for 4G wireless broadband access and beyond,” in Proc. PIERS, 2011, pp. 1396–1399.
[20] Y. Zhou, T.-S. Ng, J. Wang, K. Higuchi and M. Sawahashi, “OFCDM: a promising broadband wireless access technique,” Commun. Mag., vol. 46, no. 3, pp. 38-49, Mar. 2008
[21] R. A. Shafik, S. Rahman, and R. Islam, “On the extended relationships among EVM, BER and SNR as performance metrics,” in proc. ICECE, 2006, pp. 408-411.
[22] J. Lowery, “Amplified-spontaneous noise limit of optical OFDM lightwave systems,” Opt. Exp., vol. 16, no. 2, pp. 860-865, Jan. 2008.
[23] A. Ali, H. Paul, J. Leibrich, W. Rosenkranz, and K.-D. Kammeyer, “Optical Biasing in Direct Detection Optical-OFDM for Improving Receiver Sensitivity,” in Proc. OFC/NFOEC, San Diego, CA, 2010, paper CF1F.5.
[24] J.-H. Yan, Y.-W. Chen, B.-C. Tsai, and K.-M. Feng, “A Multiband DDO-OFDM System with Spectral Efficient Iterative SSBI Reduction DSP,” IEEE Photon. Technol. Lett., vol. 28, no. 2, pp. 119-122, Oct. 2016.
[25] W.-R. Peng, I. Morita, H. Takahashi, and T. Tsuritani, “Transmission of high-speed (> 100 Gb/s) direct-detection optical OFDM superchannel,” J. Lightw. Technol., vol. 30, no. 12, pp. 2025-2034, 2012.
[26] K. Grobe and J. Elbers, “PON in adolescence: from TDMA to WDM-PON,” IEEE Commun. Mag., vol. 46, no. 1, pp. 26-34, Jan. 2008.
[27] N. Cvijetic, M.-F. Huang, E. Ip, Y. Shao, Y.-K. Huang, M. Cvijetic, and T. Wang, “Coherent 40Gb/s OFDMA PON for long-reach (100+ km) high-split ratio (>1:64) optical access/metro networks,” in Proc. OFC/NFOEC, Los Angeles, CA, 2012, paper OW4B.8.
[28] N. Cvijetic, M. Cvijetic, M.-F. Huang, E. Ip, Y.-K. Huang, and T. Wang, “Terabit Optical Access Networks Based on WDM-OFDMA-PON,” J. Lightw. Technol., vol. 30, no. 4, pp. 493-503, Feb. 2012.
[29] W. Shieh, “PMD-Supported Coherent Optical OFDM Systems,” IEEE Photon. Technol. Lett., vol. 19, no. 3, pp. 134-136, Feb. 2007.
[30] E. Giacoumidis, J. L. Wei, X. L. Yang, A. Tsokanos, and J. M. Tang, “Adaptive-Modulation-Enabled WDM Impairment Reduction in Multichannel Optical OFDM Transmission Systems for Next-Generation PONs,” IEEE Photon. J., vol. 2, no. 2, Apr. 2010.
[31] E. Giacoumidis, A. Kavatzikidis, A. Tsokanos, J. M. Tang, and I. Tomkos, “Adaptive Loading Algorithms for IMDD Optical OFDM PON Systems Using Directly Modulated Lasers,” IEEE J. Opt. Commun. Netw., vol. 4, no. 10, pp. 769-778, Oct. 2012.
[32] Z. Dong, X. Li, J. Yu, and N. Chi, “6128-Gb/s Nyquist-WDM PDM-16QAM Generation and Transmission Over 1200-km SMF-28 With SE of 7.47 b/s/Hz,” J. Lightw. Technol., vol. 30, no. 24, pp. 4000-4005, Dec. 2012.
[33] T. Hirooka, P. Ruan, P. Guan, and M. Nakazawa, “Highly dispersion-tolerant 160 Gbaud optical Nyquist pulse TDM transmission over 525 km,” Opt. Exp., vol. 20, no.14, pp. 15001-15007, Jul. 2012.
[34] Z. Dong, J. Yu, H.-C. Chien, N. Chi, L. Chen, and G.-K. Chang, “Ultra-dense WDM-PON delivering carrier-centralized Nyquist-WDM uplink with digital coherent detection,” Opt. Exp., vol. 19, no. 12, pp. 11100-11105, Jaun. 2011.
[35] P. C. Schindler, R. M. Schmogrow, M. Dreschmann, J. Meyer, D. Hillerkuss, I. Tomkos, J. Prat, H.-G. Krimmel, T. Pfeiffer, P. Kourtessis, J. Becker, C. Koos, W. Freude, and J. Leuthold, “Flexible WDM-PON with Nyquist-FDM and 31.25 Gbit/s per Wavelength Channel Using Colorless, Low-Speed ONUs,” in Proc. OFC, Anaheim, CA, 2013, paper OW1A.5.
[36] K. Kikuchi, “Polarization-demultiplexing algorithm in the digital coherent receiver,” in proc. LEOS, 2008, pp. 101-102.
[37] S. Gosselin, A. Pizzinat, X. Grall, D. Breuer, E. Bogenfeld, J. T. Gijón, A. Hamidian, and N. Fonseca, “Fixed and Mobile Convergence: Which Role for Optical Networks?,” in Proc. OFC, 2015, paper Th3H.2.
[38] C. Liu, A. Yi, M. Zhu, J. Wang, L. Zhang, S.-C. Shin, Z. Dong, H.-C. Chien, J. Yu, C. Su, G. Gu, A. Ng'Oma, G.-K. Chang, “A novel direct-modulation envelope-detection Pol-Mux MIMO RoF system based on blind equalization techniques,” in Proc. OFC/NFOEC, Anaheim, CA, 2013, paper OM3D.6.
[39] M. Zhu, F. Li, F. Lu, J. Yu, C. Su, G. Gu, and G.-K. Chang, “Wavelength Resource Sharing in Bidirectional Optical Mobile Fronthaul,” J. Lightw. Technol., vol. 33, no. 5, pp. 3182-3188, Aug. 2015.
[40] C.-W. Chow, C.-H. Yeh, C.-H. Wang, F.-Y. Shih, C.-L. Pan, and S. Chi, “WDM extended reach passive optical networks using OFDM-QAM,” Opt. Exp., vol. 16, no. 16, pp. 12096-12101, Aug. 2008.
[41] G. P. Agrawal, Nonlinear fiber optics, 5th ed. Oxford, UK, 2013.
[42] L. Mehedy, M. Bakaul, and A. Nirmalathas, “Single-Channel Directly Detected Optical-OFDM Towards Higher Spectral Efficiency and Simplicity in 100 Gb/s Ethernet and Beyond,” IEEE J. Opt. Commun. Netw., vol. 3, no. 5, pp. 426-434, May 2011.
[43] W.-R. Peng, “Analysis of Laser Phase Noise Effect in DirectDetection Optical OFDM Transmission,” J. Lightw. Technol., vol. 28, no. 17, pp. 2526-2536, Sep. 2010.
[44] ITU-T Recommendation G.975.1, Appendix I.9, 2004.
[45] X. Steve Yao, L.-S. Yan, B. Zhang, A. E. Willner, and J. Jiang, “All-optic scheme for automatic polarization division demultiplexing,” Opt. Exp., vol. 15, no. 12, pp. 7407-7414, Jun. 2007.
[46] C.-C. Wei, C.-T. Lin, C.-Y. Wang, and F.-M. Wu, “A novel polarization division multiplexed OFDM system with a direct-detection BLAST-aided receiver,” in Proc. OFC, 2013, paper. JTh2A.49.
[47] D. Qian, N. Cvijetic, J. Hu, and T. Wang, “108 Gb/s OFDMA-PON With Polarization Multiplexing and Direct Detection,” J. Lightw. Technol., vol. 28, no. 4, pp. 484-493, Feb. 2010.
[48] C. Xie, “PMD Insensitive Direct-Detection Optical OFDM Systems Using Self-Polarization Diversity,” in Proc. OFC, 2008, paper. OMM2.
[49] W.-R. Peng, K.-M. Feng, and A. E. Willner, “Direct-Detected Polarization Division Multiplexed OFDM Systems with Self-Polarization Diversity,” in Proc. LEOS, 2008, paper. MH3.
[50] M. Martinelli, “A universal compensator for polarization changes induced by birefringence on a retracing beam,” Opt. Commun., vol. 72, no. 6, pp. 341-344, 1989.
[51] P. Drexler and P. Fiala, “Utilization of Faraday mirror in fiber optic current sensors,” Radioengineering, vol. 17, no. 4, pp. 101–107, 2008.
[52] M. Bourennane, F. Gibson, A. Karlsson, A. Hening, P. Jonsson, T. Tsegaye, D. Ljunggren, and E. Sundberg, “Experiments on long wavelength (1550nm) "plug and play" quantum cryptography systems,” Opt. Exp., vol. 4, no. 10, pp. 383-387, 1999.
[53] R. E. Wagner, C. D. Poole, H. J. Schulte, N. S. Bergano, V. P. Nathu, J. M. Amon, R. L. Rosenberg, and R. C. Alfmess, “Polarizcrrion Measurements on a 147 km Lightwave Undersea Cable,” in Proc. OFC, 1986, paper PD7-1.
[54] H.-Y. Chen, C.-C. Wei, I-C. Lu, H.-H. Chu, Y.-C. Chen, and J. Chen, “High-Capacity and High-Loss-Budget OFDM Long-Reach PON Without an Optical Amplifier,” IEEE J. Opt. Commun. Netw., vol. 7, no. 1, pp. A59-A65, Jan. 2015.
[55] N. Cvijetic, “OFDM for Next-Generation Optical Access Networks,” J. Lightw. Technol., vol. 30, no. 4, pp. 384-398, Feb. 2012.
[56] N. Cvijetic, D. Qian, and J. Hu, “100 Gb/s Optical access based on optical orthogonal frequency-division multiplexing,” Commun. Mag., vol. 47, no. 7, pp. 70-77, Jul. 2010.
[57] C. W. Chow, C. H. Yeh, and J. Y. Sung, “OFDM RF power-fading circumvention for long-reach WDM-PON,” Opt. Exp., vol. 22, no. 20, pp. 24392-24397, Oct. 2014
[58] T. Minn and K.-Y. Siu, “Dynamic Assignment of Orthogonal Variable-Spreading-Factor Codes in W-CDMA,” J. Sel. Area. Comm., vol. 18, no. 8, pp. 1429-1440, Aug. 2015.