雙向光纖有線電視及微波傳輸系統之再調變技術

Bidirectional fiber optical CATV modulation and Phase remodulation ROF transport systems

姜沛志(Pei-Chih Chiang)

指導教授 ： 呂海涵

國立臺北科技大學/電資學院/光電與通訊產業研發碩士專班/碩士(2011年)

https://doi.org/10.6841/NTUT.2011.00363

摘要

光纖有線電視與光纖微波傳輸系統提供一個非常好的方式來整合有線電視、光纖及無線技術。本實驗為一個雙向的傳輸系統架構，它整合了多載波的類比電視訊號與數位訊號的再次相位調變，在一個單光學波長能同時為這2個系統所應用。
比較相位調變與強度調變，優點是不需額外的偏壓或是控制電路來操控，使的傳輸端可靠度增加、系統簡單化及更為輕巧。另外相位調變器提供強度一致的光信號，可提高許多抗非線性的能力。因為相位調變接收端的光偵測器無法直接接收相位訊號，所以相位轉強度的解調變元件也十分重要。
利用調變器的特性，同時傳輸兩種訊號，分別為強度調變的光纖有線電視及相位方式調變的微波訊號，這個架構為一個全雙工的系統，首先雷射直接調變多載波的電視訊號，再經光纖傳送經過相位調變器，調變另一數位訊號回到頭端。在解調變的元件，使用延遲器，來解調回強度訊號。在端點上所測得的載波雜訊比、載波合成二次拍差比、載波合成三次拍差比及誤碼率，都符合有線電視及光纖微波系統的性能要求。

關鍵字

直接調變 ； 相位調變 ； 光纖有線電視 ； 光纖微波

並列摘要

Fiber optical cable television (CATV) systems in combination with radio-on-fiber (ROF) technologies provide a very promising candidate to combine the advantages of cable, fiber optics and wireless. This experiment is a transpor system structure, with directly modulating CATV signal and phase-remodulating ROF signal, by modulating multi-carriers CATV signal in amplitude domain and ROF signal in phase domain, a single optical wavelength is able to serve these two applications simultaneous.
Phase modulation (PM) has many advantages over intensity modulation(IM). It requires no biasing or other external control at the modulator, which improves the reliability, simplicity and size. It also has high robustness against fiber nonlinear because constant optical intensity signal. At the receiver of PM transport system, because photodetection is phase insensitive, a phase-intensity conversion demodulator is needed.
To utilize those characteristics, two fiber-optic transport systems are developed to simultaneously transmit CATV signal in amplitude domain and ROF signal in phase domain, we proposed and demonstrated a full-duplex transport system. We study hybrid CATV/ROF scheme using cost-effective directly modulated laser to generate downstream Multi-carrier CATV signal and provide upstream radio signals using a phase demodulated technology. For demodulator, we utilize a delay line (DI) to transform the phase signal to intensity signal. The obtained carrier-to-noise ratio (CNR), composite second-order (CSO), and composite triple beat (CTB) and bit error rate (BER) performance, not only satisfy the fiber optical CATV requirements, but also meet the high quality ROF demands over single-mode fiber (SMF) transmissions.

並列關鍵字

Directly modulated ； Phase remodulation ； Fiber optical cable television ； Radio-over-Fiber

參考文獻

[1] B. Masella and X. Zhang, “A novel single wavelength balanced system for radio-over-fiber links,” IEEE Photon. Technol. Lett., vol. 18, pp. 301-303, 2006.

[2] K. M. Choi, S. M. Lee, M. H. Kim, and C. H. Lee , “An Efficient Evolution Method From TDM-PON to Next-Generation PON,” IEEE Photon. Technol. Lett., vol. 19, pp. 647-649, 2007.

[3] C. H. Lee, W. V. Sorin and B. Y. Kim, “Fiber to the Home Using a PON Infrastructure,” J. of Light. Technol. 24, 4568-4583 2006.

[4] Rujian Lin, “Next Generation PON in Emerging Networks,” Proc. OFC/NFOEC 2008, OWH1.

[5] K. M. Choi and C. H. Lee, “A Low-Noise Broadband Light Source for a WDM-PON Based on Mutually Injected Fabry–Pérot Laser Diodes With RF Modulation,” IEEE Photon. Technol. Lett. vol. 20, pp. 2072-2075, 2008.