以陣列波導光柵(AWG)構成的編解碼器已被架構於光區域網路中(optical LAN)。為了提升系統使用者個數與強化系統私密性，我們提出一套群組波長跳頻與展時編碼系統(time-spreading and wavelength-group-hopping)，進而以陣列波導光柵為編解碼器來實現私密性較高的光纖到家(FTTH)網路。
我們將此編碼方式同時應用於時域和頻域中而發展出一套二維光碼。在時域編碼裡，我們使用傳統的質數碼(prime code)。在頻域編碼裡，質數碼及最大長度序列碼將同時運用。重要的是，此系統根據最大長度序列碼之長度將寬頻光源(BLS)分成G個波長群組。而每一個群組即為一跳頻細元(hopping chip)且符合陣列波導光柵路由器之自由頻譜區間距離(FSR interval)。在本論文中，我們利用陣列波導光柵本身具備的循環(cyclic)及自由頻譜區間(FSR)之特性，將展時與群組跳波並內嵌最大長度序列碼之編碼系統架構於光纖到家網路中。
本論文也探討到多重存取干擾(MAI)對於此系統的影響以及本系統在位元錯誤率(BER)的表現。經由比較之後，本系統之位元錯誤率也較優於傳統的質數跳頻碼(prime-hop code)。此外，群組波長跳頻與展時編碼技術同時也提供更高的私密性於光分碼多工系統。

The arrayed-waveguide grating-based (AWG-based) coder/decoder (codec) is configured over optical local-area networks (LANs). In order to increase the number of subscribers and enhance the confidentiality of the optical CDMA (OCDMA) system, we proposed a coding scheme named time-spreading and wavelength-group-hopping (TS/GH scheme), and developed an AWG-based system for excellent data confidentiality over Fiber-to-the-Home (FTTH) network.
The proposed code matrix, which is coded in time and spectral (wavelength) domain, is referred as two-dimensional (2-D) optical codes. In time domain, we utilized conventional prime code. However, both prime code and maximum-length sequence (M-sequence) code were utilized in spectral domain. Importantly, for the proposed broadband light source (BLS), the total number of available wavelengths is partitioned into G different groups based on M-sequence code length. Every group is referred as hopping chip and characterized by the free-spectral-range (FSR) interval of AWG router.
Due to cyclic property of M-sequence codes and hopping chip is characterized by the FSR of AWG router. In this thesis, we exploited the inherent cyclic and periodic FSR properties of AWG router, the proposed scheme is configured by AWG-based codec over FTTH network.
The multiple-access interference (MAI) and bit error rate (BER) of the proposed scheme are also evaluated and the result reveals that the BER of the proposed scheme is better than conventional prime-hop code (PHC). Moreover, the proposed TS/GH scheme provides higher confidentiality for OCDMA system.

References
[1] K. S. Kim, “On The Evolution of PON-Based FTTH Solutions,” Information Sciences, vol. 149/1-2, pp. 21-30, Jan. 2003.
[2] C. H. Lee, W. V. Sorin and B. Y. Kim, ” Fiber to the Home Using a PON Infrastructure (invited paper),” J. Lightwave Technol., vol. 24, no. 12, pp. 4568-4583, Dec. 2006.
[3] J. R. Stern, C. E. Hoppitt, D. B. Payne, M. H. Reeve, K. A. Oakley, “ TPON-A Passive Optical Network for Telephony,” Fourteenth European Conference on Optical Communication (ECOC'88), vol. 1, pp. 203-206, Brighton, UK, Sep. 1988.
[4] G. Kramer, B. Mukherjee, and G. Pesavento, “Ethernet PON (ePON): Design and Analysis of an Optical Access Network,” Photonic Network Communications, vol. 3, no. 3, pp.307-319, July 2001.
[5] G. Kramer and G. Pesavento, “Ethernet passive optical network (EPON): building a next-generation optical access network,” IEEE Communications Magazine, vol. 40, pp. 66-73, Feb. 2002.
[6] S. J. Park, C. H. Lee, K. T. Jeong, H. J. Park, J. G. Ahn, and K. H. Song, “Fiber-to-the-Home Services Based on Wavelength-Division-Multiplexing Passive Optical Network,” J. Lightwave Technol., vol. 22,no. 11, pp. 2582-2591, Nov. 2004.
[7] S. Dixit, “IP over WDM: Building the Next-Generation Optical Internet,” John Wiley and Sons, Inc., New Jersey, 2003.
[8] A. Sierra, S. V. Kartalopoulos, “Evaluation of Two Prevalent EPON Networks Using Simulation Methods,” International Conference on Internet and Web Applications and Services/Advanced International Conference (AICT-ICIW '06), Feb. 2006.
[9] K. Kitayama, X. Wang, N. Wada, “OCDMA over WDM PON - Solution Path to Gigabit-Symmetric FTTH,” J. Lightwave Technol., vol. 24, no. 4, pp. 1654-1662, Apr. 2006.
[10] A. Stok and E. H. Sargent,” The role of optical CDMA in access networks,” IEEE Communications Magazine, vol. 40, pp. 83-87, Sep. 2002.
[11] A. Stok and E. H. Sargent, “Lighting the local Area: Optical code-division multiple access and quality of service provisioning,” IEEE Network, vol. 14, no. 6, pp. 42-46, Nov. 2000.
[12] N. Nadarajah, E. Wong, A. Nirmalathas, “Implementation of multiple secure virtual private networks over passive optical networks using electronic CDMA,” IEEE Photon. Technol. Lett., vol. 18, no. 3, pp. 484-486, Feb. 2006.
[13] R. Dixon, “Why spread spectrum?,” IEEE Communications Soc. Mag., vol. 13, pp. 21-25, July 1975.
[14] R. Scholtz, “The spread spectrum concept,” IEEE Transactions on Communications, vol. 25, no. 8, pp. 748-755, August 1977.
[15] R. Dixon, “Spread Spectrum Systems with Commercial Applications,” Wiley- Interscience, New York, 1994.
[16] M. Sust, “Code division multiple access for commercial communications,” in Review of Radio Science 1992-1994, pp. 155-179, International Union of Radio Science (URSI).
[17] E. Marom and O. G. Ramer, “Encoding-decoding optical fiber network,” Electron. Lett., vol. 14, no. 3, pp. 48-49, 1978.
[18] J. A. Salehi, “Code division multiple-access techniques in optical fiber network-Part I: Fundamental principles,” IEEE Transactions on Communications, vol. 37, no. 8, pp. 824-833, Aug. 1989.
[19] G. Vannucci, “Combining frequency division multiplexing and code division multiplexing for high capacity optical network,” IEEE Network, vol. 3, no. 2, pp. 21-30, Mar. 1989.
[20] J. A. Salehi and C. A. Brackett, “Code division multiple-access Techniques in optical fiber networks-Part II: Systems performance analysis,” IEEE Transactions on Communications, vol. 37, no. 8, pp. 834-842, Aug. 1989.
[21] Z. Wei, H. M. H. Shalaby, and H. Ghafouri-Shiraz, “Modified quadratic congruence codes for fiber bragg-grating-based spectral-amplitude-coding optical CDMA systems,” J. Lightwave Technol., vol. 19, no. 9, pp. 1274-1281, Sep. 2001.
[22] C.C. Yang, J.F. Huang, and S.P. Tseng, “Optical CDMA network codecs structured with M-sequence codes over waveguide-grating router,” IEEE Photon. Technol. Lett., vol. 16, pp. 641-643, Feb. 2005.
[23] T. H. Shake, “Security performance of optical CDMA against eavesdropping,” J. Lightwave Technol., vol. 23, pp. 655-670, Feb. 2005.
[24] L. Tančevski, I. Andonovic, M. Tur, and J. Budin, “Hybrid wavelength hopping/time spreading code division multiple access systems,“ IEE Proc.-Optoelectron., vol. 143, no. 3, pp. 161-166, June 1996.
[25] L. Tančevski, I. Andonovic, and J. Budin, “Secure optical network architectures utilizing wavelength hopping/time spreading codes,” IEEE Photonics Technol. Lett., vol. 7, no. 5, pp. 573-575,May 1995.
[26] F. R. K. Chung, J. A. Salehi, and V. K. WEI, “Optical Orthogonal Codes: Design, Analysis, and Applications,” IEEE Trans. Information Theory, vol.35, no.3, pp.595-604, May 1989.
[27] P. R. Prucnal, M. A. Santoro, and T. R. Fan, “Spread Spectrum Fiber-Optic Local Area Network Using Optical Processing,” J. Lightwave Technol., vol. LT-4, no. 5, pp. 547-554, May 1986.
[28] A. A. Shaar, C. F. Wooddock, and P. A. Davies, “Bounds on the Cross-Correlation Functions of State M-Sequences,” IEEE Trans. Commun., vol. COM-35, no. 3, ppp. 305-312, March 1987.
[29] H. Takahashi, K. Oda, H. Toba, and Y. Inoue, “Transmission characteristics of arrayed-waveguide N×N wavelength multiplexer,” J. Lightwave Technol., vol. 13, no. 3, pp. 447-455, March 1995.
[30] B. Vidal, D. Madrid, J. L. Corral, and j. Marti, “Novel Photonic True-Time-Delay Beamformer Based on the Free-Spectral-Range Periodicity of Arrayed Waveguide Gratings and Fiber Dispersion,” IEEE Photon. Technol., vol. 14, no. 11, pp. 1614-1616, Nov. 2002.
[31] T. J. Chan, C. K. Chan, K. Chan, W. Hung, and L. K. Chen, ”A Novel WDM Passive Optical Network with Bi-directional Protection”, Proceedings of SPIE, vol.4909, pp. 167-173, 2002.
[32] C. Bock, J. Prat, and S. D. Walker,” Hybrid WDM/TDM PON Using the AWG FSR and Featuring Centralized Light Generation and Dynamic Bandwidth Allocation”, J. Lightwave Technol., vol. 23, no. 12, Dec. 2005.
[33] H. Fathallah, L. A. Rusch, and S. LaRochelle, “Passive Optical Fast Frequency-hop CDMA Communication System,” J. Lightwave Technol., vol. 17, no. 3, Mar. 1999.
[34] Jen-Fa Huang; Yao-Tang Chang; Chuan-Ching Sue; Deng-Sheng Wang, “Reconfigurable Coded WDM with Arrayed-Waveguide-Gratings to Enhance Confidentiality on Fiber-to-the-Home Networks,” Communications, 2006 Asia-Pacific Conference, Aug. 2006.
[35] L. R. Chen, “Technologies for hybrid wavelength/time optical CDMA transmission,” Conference on Electrical and Computer Engineering, Canadian, vol. 1, pp. 435-440, 2001.
[36] M. C. Parker, F. Farjady, and S. D. Walker, “Wavelength-Tolerant Optical Access Architectures Featuring N-Dimensional Addressing and Cascaded Arrayed Waveguide Gratings,” J. Lightwave Technol., vol. 16, no. 12, Dec. 1998.
[37] H. Heo, S. S. Min, Y. H. Won, Y. Yeon, B. K. Kim, and B. W. Kim, “A New Family of 2-D Wavelength-Time Spreading Code for Optical Code-Division Multiple-Access System With Balanced Detection,” IEEE Photon. Technol., vol. 16, no. 9, pp. 2189-2191, Sep. 2004.