【作者】 昌庆江；

【导师】 苏翼凯；

【作者基本信息】 上海交通大学 ， 通信与信息系统， 2009， 博士

【摘要】 Radio over Fiber(RoF)宽带无线接入网络是新兴的研究领域,它结合光纤通信和无线通信两大技术,可以实现超过Gb/s无线业务的传输,在未来高速宽带无线通信系统中具有重要的应用。本论文研究了RoF宽带无线接入网络中的若干关键技术,提出并设计新颖的RoF系统结构,主要进行如下几方面的研究:1.光子产生射频信号技术在RoF系统中,需要使用高频信号携载高速数据以提高无线通信系统的容量,但是目前采用电产生高频信号的方法难度大、成本高、技术复杂。而光子产生高速射频信号具有显著的优点,是实现RoF的关键技术之一。本论文提出三种新颖的光子产生射频信号的技术方案:1)光子产生六倍频的高速毫米波:基于两个级联的单驱动马赫曾德调制器(MZM),采用10-GHz的微波信号,光子产生60-GHz的毫米波。传统的方案如果要得到超过四倍频的射频信号,需要结合四波混频非线性效应和光域的滤波。该方案不需要非线性处理,以及光域和电域上的滤波;而且在频率上具有可扩展性,如果采用当前成熟的40-GHz光电器件,可以得到240-GHz的亚毫米波。2)光子产生四倍频的高速毫米波:基于单个集成的双平行马赫曾德调制器(DPMZM),采用10-GHz的微波信号,光子产生40-GHz的毫米波。该方案在频率上具有扩展性;电信号处理简单,不需要严格的电信号相位匹配;也不需要光域和电域的滤波;采用单个的集成调制器,插入损耗低、结构简单、容易控制。3)24-GHz超宽带(UWB)脉冲射频信号:基于DPMZM和级联的单驱动MZM,集成光子产生和光子上变频技术,得到24-GHz超宽带(UWB)脉冲射频信号。我们还首次对24-GHz的超宽带信号在光纤传输中的性能进行了测试和分析。2.应用于双向RoF系统的OCS-DPSK调制格式研究在RoF系统中,需要同时传输下行和上行信号,以满足交互式业务的需求,因此,双向RoF系统设计也是关注的热点。本论文首次提出采用新颖的光载波抑制-差分相移键控(OCS-DPSK)信号,实现双向RoF系统中三个关键的功能:将基带信号上变换到射频频段,产生远端本振信号以及上行数据重调制,从而最小化RoF接入网络的配置成本。我们提出两种新颖的OCS-DPSK信号产生技术:1)基于幅移键控(ASK)到差分相移键控(DPSK)调制格式的转换,采用单个集成的DPMZM,通过抑制OCS-ASK信号的两个边带中离散的直流成分,得到OCS-DPSK调制格式。相比较传统的OCS-DPSK发射机,提出的方案具有结构紧凑、插入损耗低等显著优点。2)基于单驱动MZM,通过产生双极性的电副载波信号,以及利用光载波抑制技术,得到OCS-DPSK信号。提出的方案只采用单个调制器,并且实现了双向RoF系统的三个关键功能,最小化整个RoF系统的配置成本。3)我们还延伸了单驱动MZM产生OCS-DPSK调制格式的原理,采用单个的DPMZM,首次提出并实验演示了在RoF系统中产生和传输新颖的OCS-DQPSK信号。在RoF传输系统,OCS-DQPSK调制格式可以实现在公共的射频载波上传输多个无线业务,提高射频频谱效率。3.融合RoF和PON技术的混合多业务传输系统的设计在未来的光通信中,既需要提供光纤到户的宽带有线接入服务,也需要用光纤传输宽带无线业务。因此,融合RoF和无源光网络(PON)技术,将无线和有线业务集中整合到同一个网络结构中,成为当前RoF研究领域的又一个热点。我们提出三种新型的、在单载波上提供混合多业务的系统设计方案:1)多波段RoF系统设计:采用DPMZM和级联的单驱动MZM,基于光载波抑制和频谱搬移技术,同时产生和传输有线基带数据、两倍频的无线微波信号,和四倍频的无线毫米波信号。2)集成RoF技术的WDM-PON双广播业务分发系统:通过设计正交相位/强度调制码型和光副载波格式,首次实现了在单载波上同时传输点对点的高速下行数据信号和点对多点的双广播业务。3)融合RoF技术分发三重混合业务的WDM-PON系统:采用集成的DPMZM,实现了在单载波上同时传输单个有线业务和两种无线业务的三重混合业务的功能。该方案只需要单个集成的调制器,具有结构紧凑、成本有效、信号容易控制、插入损耗低等优点。4. RoF系统中的光子射频信号处理技术光子射频信号处理突破了传统的电处理方法的带宽瓶颈,而且具有处理速度快、精度高、不受电磁干扰、传输损耗低等优点,在RoF系统中具有重要的地位。我们首次将硅波导器件应用于RoF系统中,具有开创性的意义。基于硅波导环形谐振腔的非线性效应,设计出新颖的光子上变频器和光子射频移相器:1)利用硅波导环形谐振腔的自由载流子色散效应,设计并实验演示了微米刻度的光子上变频器,将1-Gb/s的基带数据成功上变频到40-GHz的毫米波,提出的方案可以实现毫米波频率可扩展的光子上变频器。2)采用硅波导环形谐振腔器件的非线性热效应,设计并实验演示了40-GHz的高速光子射频移相器,相移的范围达到4.6弧度,这是目前实验报道的最高频率的光子射频移相器。同时还实验验证了该光子射频移相器的相移响应速度。更多还原

【Abstract】 Radio over Fiber (RoF) broadband wireless access network, the integration of optical fiber and wireless technology, is an emerging research field. It entails the use of optical fiber links to deliver radio frequency (RF) signal, with the advantages including huge bandwidth、low attenuation loss and immunity to RF interference. RoF technique is a powerful solution to provide broadband wireless access services with increased mobility and reduced cost. Our thesis focuses on the researches of the key technologies and system design as follows:1. Photonic generation of high-speed RF signalThe use of high-speed RF signal in the RoF systems is receiving increasing interests since it can be used as RF carrier or local oscillator signal for providing broadband wireless access services. To save costly electrical hardware, all-optical generations of milimeter-wave signals have attracted much attention. We propose three novel schemes for photonic generation of RF signal:1)Photonic generation of six-fold frequency millimetre-wave(MMW): We propose and experimentally demonstrate to generate 60-GHz MMW based on two cascaded 10-GHz single drive Mach-Zehnder modulators (MZMs). The scheme is scalable in frequency band if faster devices are employed, thus up to 240-GHz high speed MMW can be obtained using currently available 40-GHz components.2)Photonic generation of quadruple frequency MMW: We propose and experimentally demonstrate a novel scheme to generate frequency-quadrupled MMW using an integrated dual-parallel Mach-Zehnder modulator (DPMZM). A 40-GHz high-speed MMW is obtained based on a 10-GHz RF signal.3)24-GHz Ultra-Wideband over Fiber System: We propose and experimentally demonstrate a 24-GHz UWB over fiber system with a simple structure using photonic generation and frequency up-conversion technique. The performance of the up- converted UWB pulses after the fiber transmission is also studied.2. OCS-DPSK modulation format in bi-directional RoF systems Optical carrier suppression-differiential phase-shift keying (OCS-DPSK) is an effective modulation format in bi-directional RoF systems to realize flexible applications in future broadband access networks. We propose two novel methods to generate OCS-DPSK using single intensity modulator:1)Generation of OCS-DPSK using ASK to DPSK format conversion: We experimentally demonstrate to produce an OCS-DPSK format using one DPMZM. The proposed scheme is based on ASK to DPSK format conversion by suppressing the spectral tones of an optical carrier suppression-amplitude shift keying (OCS-ASK) signal.2)Generation of OCS-DPSK using one single drive MZM: This scheme realizes three key functions in full-duplex RoF systems: up-conversion of baseband data for downlink wireless service delivery, generation of remote local oscillator (LO) signal for down-conversion of uplink wireless signal, and re-modulation of down-converted uplink data, thus greatly lowering the cost of base stations.3)In addition, based on the OCS-DPSK generation principle, an optical carrier suppression-differiential quadruple phase-shift keying (OCS-DQPSK) signal is also obtained using a DPMZM for simultaneously delivering multiple RoF services at the common RF carrier.3. Convergence of RoF and PON to provide hybide multiple sevicesThe future broadband access networks demand large bandwidths and high data rate for data-intensive multimedia and real-time applications. It is desirable to simultaneously deliver wireline and wireless signals using the same fiber infrastructure with cost-effective configurations. We present three novel schemes to provide hybrid multiple services by convergeing RoF and passive optical network (PON) techniques with centralized wavelength:1)Multiband RoF transmission systems: We propose a novel multi-band RoF system and experimentally demonstrate the simultaneous generation and transmission of the downstream1.25-Gb/s baseband, 20-GHz microwave and 40-GHz millimiter-wave signals and upstream symmetric data. The system uses 10-GHz components to achieve frequency doubling and quadrupling, and without the need of additional light source and wavelength management at the base station.2)Convergence of RoF to deliver high-speed point-to-point downlink data and double broadcast services in wavelength division multiplexing-passive optical network (WDM-PON) systems: We propose and experimentally demonstrate that double broadcast services can be overlaid over high-speed point-to-point downlink data with centralized light sources and shared fiber infrastructure in a WDM-PON system.3)Intergration with RoF to provide one wireless and double wireline services in WDM-PON systems: We propose and experimentally demonstrate a WDM-PON system simulataneously providing triple different services with centralized light source and shared optical-fiber infrastructure based on a single DPMZM.4. Photonic RF signal processing based on silicon micro-ring resonatorPhotonic RF signal processing has particular advantages since it is more efficient, less complex, and less costly than conventional electronic systems, especially at high- speed millimeter wave frequencies. We present and experimentally demonstrate two important photonic RF devices including photonic up-converter and photonic RF phase shifter based on silicon micro-ring resonator:1)Photonic RF up-converter: Based on the free-carrier dispersion effect in a resonance-split silicon microring resonator, we experimentally demonstrate a novel micrometer-scale optical up-converter for up-converting a 1-Gb/s baseband data to 40-GHz millimeter-wave in RoF systems.2) Photonic RF phase shifter: Based on the thermal nonlinear effect of the silicon microring, a prototype of the phase shifter is experimentally demonstrated for a 40-GHz signal with a 4.6-rad tuning range. We also experimenally verify the phase shift response speed of the designed photonic RF phase shifter.更多还原