一种基于LTCC基板的数字光收发模块设计

首先介绍低温共烧陶瓷(LTCC)技术和数字光收发模块,阐述LTCC的技术特点、工艺流程以及它相较于传统PCB电路基板的优势,解释了数字光收发模块的通信原理和工作方式;其次,提出了一种基于LTCC电路基板的数字光收发模块的设计方案,详细介绍了该光模块的主要构成和实现方法,包括电路设计和关键器件的比较和选取;最后,通过对该方案所述的数字光收发模块的样件进行关键指标和性能测试,验证了该设计方案的可行性。     

Reflective SOA-Based Bidirectional WDM-PON Sharing Optical Source for Up/Downlink Data and Broadcasting Transmission

We proposed and experimentally demonstrated the reflective semiconductor optical amplifier (RSOA)-based wavelength-division-multiplexed passive optical network (WDM-PON) scheme where not only up/downlink data services but also broadcasting service could be provided using a single optical source. In the proposed scheme, the digital signal and subcarrier multiplexing (SCM) signal for downstream were simultaneously modulated by a single distributed feedback laser diode and RSOA in optical network unit remodulated downstream source as an upstream. Without performance deterioration of digital signals both in up- and downstream, the proposed WDM-PON scheme can stably offer the SCM signal for broadcasting service. In the experiment, 1-Gb/s digital signals both for up- and downstream and 20-Mb/s SCM signal at 2.2 GHz for broadcasting were demonstrated in 10-km bidirectional link     

光性能检测系统中纳秒脉冲峰值检测方法(英)

In optical performance monitoring system,the analog to digital converter is needed to detect the peak of nanosecond pulse and get the signal envelope.A scheme based on a designed anti-aliasing filter and analog to digital converter is proposed to broaden the nanosecond pulse and make it easier for the analog to digital converter to catch the peak of the nanosecond pulse.The experimental results demonstrate that,with the proposed scheme,the optical performance system needs less time to get the recovered eye-diagram of high speed optical data signal,and is robust to phase mismatch in the analog to digital converter circuit.     

单向实时数字视频传输中帧同步锁定技术研究

提出一种适用于单向实时数字视频传输系统的帧同步锁定方案。其方法在接收端采用本地参考时钟、状态机、锁相环，并结合CIMT编码方式实现系统自动维持帧同步锁定，而无需周期性加入帧同步码。对该帧同步锁定方案与周期性加入帧同步码强制锁定方案进行性能比较．并将其应用到单向实时数字视频光纤传输系统中。实验证明，系统自动实现帧同步锁定的方案是单向实时数字视频传输系统实现帧同步锁定的最佳方案。     

雷达信号光纤传输系统

本文提出雷达信号光纤传输系统的两个设计方案,其中第一个方案采用数字信号与模拟信号分别传输的办法,第二个方案采用全数字传输。根据第一方案设计的系统已研制成功并应用于某型号雷达,第二个方案正在研制中,同时本文还对系统所使用的关键技术进行了论述。另外提出了几种适合长距离的雷达信号光纤传输方案。     

OTDR in optical transmission systems using Er-doped fiber amplifiers containing optical circulators

Fault location in optical amplifier transmission systems is described. Optical time-domain reflectometry (OTDR) cannot be used for an optical transmission line containing traditional Er-doped fiber amplifiers (EDFAs) because they contain optical isolators. The authors propose an OTDR scheme that uses new EDFAs containing optical circulators and return transmission lines. The new EDFAs support both OTDR and digital signal transmission. A 280.9 km transmission line containing three of the proposed EDFAs was constructed and tested. Experimental results demonstrated the feasibility of OTDR fault location and 1.8-Gb/s digital signal transmission.<>     

Nonlinearity-Compensation-Free Optical Frequency Domain Reflectometry Based on Electrically-Controlled Optical Frequency Sweep

A nonlinearity-compensation-free optical frequency domain reflectometry (OFDR) scheme is proposed and experimentally demonstrated based on the electrically-controlled optical frequency sweep. In the proposed scheme, the linear frequency sweep light is generated by propagating an ultra-narrow-linewidth continuous-wave (CW) light through an electro-optic frequency shifter which consists of a dual-parallel Mach-Zehnder modulator (DPMZM) and an electronic 90° hybrid, where the electro-optic frequency shifter is driven by a linear frequency modulated signal generated by a direct digital synthesizer (DDS). Experimental results show that the spatial resolution and signal-to-noise ratio (SNR) of the proposed OFDR scheme without the nonlinear phase compensation are comparable to those of OFDR employing a commercial tunable laser source (TLS), an auxiliary interferometer, and a software-based nonlinear phase compensation method. The proposed OFDR scheme is helpful to reduce the complexity of the optical structure and eliminate the difficulty of developing the nonlinear phase compensation algorithm.     

Ultrafast Operation of Digital Coherent Receivers Using Their Time-Division Demultiplexing Function

The digital coherent receiver, which is a combination of a phase-diversity optical homodyne receiver and digital signal processing (DSP), can demodulate any multilevel coded optical signals without relying upon an optical phase-locked loop. However, the maximum symbol rate processed by such a receiver is limited by the speed of electric analog-to-digital converters and digital signal processors. Although real-time operation at 10 Gsymbol/s using an application-specific integrated circuit has recently been demonstrated, it is still difficult to increase the symbol rate beyond 40 Gsymbol/s. In order to cope with this difficulty, we propose a novel scheme, which employs a local oscillator (LO) pulsed at the subharmonic frequency of the symbol rate, enabling time-division demultiplexing of the signal at the digital coherent receiver. We demonstrate that the new type of digital coherent receiver operating at 10 Gsymbol/s can demodulate the aggregate symbol rate of 160 Gsymbol/s. From these results, we can expect ultrafast coherent optical fiber communication in the future.      

光接入网络中的数字信号处理技术

采用先进的数字信号处理(DSP)技术,在发射机和接收机分别引入预处理和后处理,以提高光接入网络的频谱效率并延长传输距离。研究了一种基于光超奈奎斯特(Super-Nyquist)滤波的类9状态正交振幅调制(9QAM)信号多模均衡(MMEQ)后端DSP算法,使用这种方案,能够有效提高频谱效率,实现了频谱效率高达4 bps/Hz的正交移相键控(QPSK)信号传输;还研究了一种基于数字SuperNyquist信号前端预处理的方案,此方案的优点是不需要光预滤波即可达到相同的频谱效率。使用一个采用直接调制激光器(DML)、直接探测和数字均衡技术的高速无载波幅度相位-64状态正交振幅调制(CAP-64QAM)系统,在20 km标准单模光纤(SSMF)上实现了创纪录的60 Gbit/s CAP-64QAM信号传输;使用相干探测,实现了速率高达100 Gbit/s的64状态正交振幅调制-正交频分复用(16QAM-OFDM)实时传输系统,解决了实时OFDM信号处理中的关键问题。     

多基地雷达光纤传输系统的设计

提出在多站雷达体系中同步和数据信号光纤传输系统的设计方案,与传统光纤传输系统在雷达中的设计不同,采用数字信号与模拟信号分别传输的办法,利用先进的光电子技术,设计并实现了一种点对多点信号光纤传输系统,系统具有动态接入和扩容的能力.同时本文还对系统涉及的关键技术进行了论述.     

Digital adaptive phase noise reduction in coherent optical links

Coherent optical links enable high-density constellations and, consequently, a higher throughput. However, the phase noise associated with the transmitter and the receiver lasers is a challenging issue in coherent lightwave systems. The authors present an approach that relies on using digital signal processing techniques to compensate for the laser phase-noise effects. The proposed approach exploits the digital processing power to address the problems arising from optical imperfections. The authors present an adaptive filtering scheme that reduces the effect of the laser phase noise and, consequently, relaxes the laser linewidth requirement. The proposed approach shows how the signal processing techniques can be exploited to compensate for the optical impairments by utilizing the continuing scale down in size and power in very large scale integration (VLSI) technology.     

Very-high-speed fibre-optic networks for broadband communications

Single-mode optical fibres have an enormous transmission bandwidth which can support ultra-high-speed digital transmission and networking. The use of electrical signal-processing, however, ultimately limits the network capacity. To eliminate the throughput bottleneck, all-optical processing techniques should be employed in a fibre-optic network. This paper discusses several schemes for implementing optical time division multiple access (OTDMA) networks with the emphasis on optical clock distribution, synchronisation and all-optical detection. The use of a fast-switching bistable laser diode as an all-optical threshold detector and data regenerator is suggested. A dual-wavelength OTDMA technique is investigated, which can be used for digital TV or future HDTV distributions. Moreover, an efficient multiple access scheme, called wavelength division multiple access with optical time division multiplexing (WDMA-OTDM), is proposed for broadband communication services. It is shown that WDMA-OTDM has all the advantages possessed by the individual OTDMA and WDMA schemes but offers improved flexibility and capacity     

一种虚拟光学数据加密的系统实现

本文在虚拟光学数据加密理论模型的基础上,研究一种并行电子系统实现方法.该系统利用TMS320C6701浮点DSP(Digital Signal Processor)实现具有多重锁、多重密钥的高密级多媒体数据加密系统.该系统具有安全性高、加/解密速度快、实时性好、适用范围宽等优点,可用于多种媒体信息如文本、图像、语音、视频等的加/解密.     

Making inexpensive micron-level measurements

This paper discusses an experiment on measuring the strain in vascular cell tissue. The resulting measurement technique used a slotted optical switch, a digital voltmeter and a reflector. Results from two runs were promising, and the repeatability was excellent. The technique is a truly inexpensive sensing scheme for micron-level measurements.     

县级有线数字电视多通道字幕插播方案

通过对基于1 550 nm长距离模拟光纤传输系统下县级有线数字电视多路字幕插播的实践,解决了县级有线网络在加扰射频数字流情况下的多路字幕插播等问题,该方案在县级有线数字电视系统中具有广泛的应用前景。     

探测器着陆小天体的自主光学导航研究

提出了一种用于探测器着陆小天体的自主光学导航方案.该方案利用探测器上的光学导航相机和激光测距仪,分别测量三个预先选定特征点的图像坐标和探测器到特征点的距离,由此得出探测器的相对位置,并利用广义卡尔曼滤波实时确定探测器的轨道.最后,通过数学仿真验证了这种自主光学导航方案的可行性,并在敏感器测量精度一定的情况下,通过仿真分析了小天体模型误差对导航精度的影响.     

Implementation of a broadband integrated services hybrid network

The issues involved in the design of a broadband integrated services digital network (B-ISDN), that utilizes optical fibers in the subscriber loop, are considered. A hybrid scheme that provides integrated access to ISDN and broadband services by delivering voice/data signals in a digital format while using an analog format for full-motion video services to subscribers is proposed. The discussion covers planning for a B-ISDN, the system concept, implementation, the loop fiber network, subscriber equipment, and cost comparison and analysis     

Online full-phase digital holographic encryption based on electrically addressed spatial light modulators

A novel full-phase digital holographic encryption scheme with double random key masks, which are performed by electrically addressed liquid-crystal spatial light modulators for optical processing, is demonstrated. Phase-shifting digital holography is employed to generate the key holograms derived from the double key masks for implementing the encryption and decryption. The experimental results show the feasibility of the full-phase encryption scheme with computer-programmable key masks for securing data via online processing.     

Off‐axis self‐reference digital holography in the visible and far‐infrared region

Recent advances in digital holography in the far‐infrared region of the spectrum have demonstrated the potential use of digital holography in homeland security as a tool to observe hostile environments in which smoke, flames, and dust impair vision. However, to make this application practical, it is necessary to simplify the optical setup. Here, we show an off‐axis, self‐reference scheme that spills the reference beam out from the object beam itself and avoids the need for a complex interferometric arrangement. We demonstrate that this scheme allows the reconstruction of high‐quality holograms of objects captured under visible as well as far‐infrared light exposure. This could pave the way to the industrialization of holographic systems to enable users to see through fire. Moreover, the quantitative nature of the holographic signal is preserved. Thus, the reported results demonstrate the possibility to use this setup for optical metrology.     

Measurement of semiconductor optical index variation in photonic devices based on optical heterodyning microwave experiments

Regarding integrated optics devices, the variation of propagation effective index is measured using an heterodyne detection scheme. Optical phase shift is so directly transferred in the microwave frequency range allowing phase measurements using common microwave network analysers. This technique is applied to a DOS (digital optical switch) technique based switch.