Next-generation optical access networks will deliver substantial benefits to consumers including a dedicated high-QoS access to bit rates of hundreds of Megabits per second. They must include the following features such as: reduced total cost of ownership, higher reliability, lower energy consumption, better flexibility and efficiency. This paper will describe recent progress and technology toward that goal using novel photonic devices

Integrated photonic micro-resonators have attracted a great deal of attention in recent years, and various types of devices are demonstrated for communication and signal processing applications. In this paper, we present some of our recent work on silicon-based microring modulators, demodulators and chromatic dispersion compensators. Signal generation in on-off-keying and differential phase-shift-keying data formats is shown, while microring filters are used to carry out the demodulation of the phase-modulated signals. We also describe how to use only two ring resonators, by combining an under-coupled one with an over-coupled one, to form an on-chip single-channel dispersion compensator.

Almost all existing resonator-based linearized optical modulators suffer from an inherent RF bandwidth narrowing that limit their applications and performance. Here, we show an ultra-linear optical modulator, called IMPACC, (Interferometric Modulator with Phase-modulating And Cavity-modulating Components) that has three unique RF bandwidth characteristics, which are not present in other resonator-based linearized optical modulators. We demonstrate these unique characteristics by contrasting IMPACC's performance to the Resonator-Assisted Mach Zehnder Interferometer (RAMZI) modulator. First, IMPACC can enhance its linearized RF bandwidth up to ~ 20% of central RF frequency (compared to ~1% for RAMZI). Second, unlike RAMZI, the RF bandwidth enhancement has a near-flat response characteristic across this bandwidth window. Third, IMPACC can maintain an excellent spurious free dynamic range (SFDR) capability (>130 dB at 1Hz bandwidth) across this window. The wide linear bandwidth capability is also demonstrated for modulation frequencies up to 75GHz.

High-speed and high-capacity optical transmission systems are being intensively investigated toward the future costeffective optical transport networks (OTN) needed to meet the huge traffic demand expected. Coherent detection with digital signal processing (DSP) is very promising to realize such systems. DSP-based linear equalizers can effectively eliminate the signal distortion caused by chromatic dispersion and polarization mode dispersion which are the main factors limiting the attainable distance of high speed channels over 40 Gb/s. Moreover, their combination with advanced modulation and polarization multiplexing techniques has yielded large capacity and spectrally-efficient transmission experiments. This paper reviews recent progress in coherent communication technologies, with special focus on higher order multi-level modulation such as quadrature amplitude modulation (QAM), and discusses higher speed transmission based on optical multiplexing techniques such as optical orthogonal frequency-division multiplexing (OFDM) toward 400G or 1T channel transport.

We present a robust post-processing technique to extract the polarization dependant frequency (PDF) and Polarization dependant loss (PDL) from stokes measurements of differential phase shift keying (DPSK) demodulators. The proposed method is based on sine-fitting on transmissions. It evaluates PDF and PDL from fitting parameters (phase, amplitude and amplitude offset) through a Muller matrix analysis.

Access networks based on optical fiber can easily fulfill high bandwidth demand and cover large service areas. Fiber access networks are also scalable to meet the future capacity request. Among several alternatives, passive optical network (PON) is considered as the most promising one, because its passive point-to-multipoint architecture is characterized by relatively low deployment and operational cost. On the other hand, the passive point-to-multipoint feature in PONs also creates a number of challenges, such as efficient resource allocation and cost-effective protection. This paper provides an overview of the advances related to these two issues and points out the research topics that are still open and need to be investigated.

Passive optical network (PON) is the leading technology being used for delivering last-mile connectivity without any active components in the distribution network. In this paper, we focus on an un-amplified hybrid tree-ring PON architecture that carries the benefits of both the tree and the ring architectures. Through simulation, we demonstrate the optical performance of the system and focus on the physical layer performance impact of interchannel and intrachannel crosstalk due to non-ideal WDM multiplexers/demultiplexers and optical switches in the system.

A potentially cost-effective radio-over-fiber (ROF)/fiber-to-the-X (FTTX)/CATV hybrid three-band transport system based on direct modulation of a distributed feedback laser diode (DFB LD) with multi-wavelength output characteristic is proposed and experimentally demonstrated. Directly modulated radio-frequency (RF) (1.25Gbps/6GHz), externally remodulated baseband (BB) (622 Mbps), and externally remodulated CATV (channels 2-78) signals are successfully transmitted simultaneously. Over an 80-km single-mode fiber (SMF) transmission, low bit error rate (BER) and clear eye diagram were achieved for ROF and FTTX applications; and good performances of carrier-to-noise ratio (CNR), composite second-order (CSO) and composite triple beat (CTB) were obtained for CATV signals. Since our proposed systems use only a directly modulated DFB LD to achieve multi-wavelength transmission, it reveals an outstanding one with simpler and more economic advantages.

This paper presents the key features of the emerging Next Generation Passive Optical Network (NG-PON) and IEEE 802.16m based Mobile Worldwide Interoperability for Microwave Access (WiMAX) networks to build a unified cost effective next generation hybrid Fiber-Wireless network. NG converged-access solutions can meet the demand for cost, mobility, bandwidth, reliability, security, and flexibility. NG-PON and 4th Generation (4G) Mobile WiMAX unified architecture enables differentiated bandwidth allocation to end users and can provide more network range and capacity at reduced operational cost. The concept of hybrid optical network unit and advanced base station (ONU-ABS) simplifies the network architecture and can save some installation and operational costs.

As a new application of Radio-on-Fiber, digital divide solution by utilizing CATV network is proposed. We have been discussed and demonstrated realization and effectively of proposed system by in-door experiment so far, however field trial is very important for the practical use. Now, the radiation examination is done as an experiment bureau in the mountainous area in Nara Prefecture aiming evaluating by the real operation, evaluating the correspondence with the link design theory, and clarifying effectiveness in a real environment of the proposal system. In this paper, the result of the field trial of the proposal and the SCM transmission is discussed and demonstrated.

Nowadays, the RoF technology can utilize to converge the broadcasting and the broadband wireless communications, because of their huge bandwidth, and protocol transparency. Transmitting RF signals are deteriorated by the nonlinearity of the RoF link and following RF amplifier. This paper provides analysis method of intermodulation distortion and peak factor of multicarrier RF signals including IEEE802.11g, ISDB-T and IEEE802.16e-2005 over intensity modulation / direct detection (IM/DD) RoF link. Experimental evaluation is also presented in terms of the error vector magnitude (EVM).

Relaxation oscillation frequency is produced when a laser is operated in the low laser threshold current region. In this operation region, a semiconductor laser shows a smooth curve, where we can observe uncertainty into defining the onset of laser oscillation. Relaxation oscillations in the laser intensity can be seen as sidebands on both sides of the main laser line. In this context, a communication system by using a relaxation oscillation frequency as an information carrier is proposed in this paper. The experimental setup is based on operation principle of direct detection, where the obtained microwave signal at the output of a fast photodetector is located on C band and it is modulated with an analog NTSC TV signal.

Continually expanding demand for greater photonic network capacities has created a need for the use of alternative wavebands and development of methods to strengthen transmission capacities. Photonic transport systems in the C band (1530-1565 nm, 4.3-THz bandwidth) and L band (1565-1625 nm, 7.1-THz bandwidth) have been extensively employed in conventional networks. We recently focused on use of a novel wavelength band such as 1.0-μm (thousand band: T band) together with the conventional C and L bands for enhancing usable optical frequency resources in future photonic networks employing wavelength division multiplexing (WDM). Therefore, here, we develop an ultra-broadband photonic transport system in the T band to create novel optical frequency resources in that waveband. In the proposed system, a holey fiber (HF) transmission line has been developed that is capable of ultra-broadband data transmission. In this study, we demonstrated ultra-broadband, 10-Gbps, error-free operation in a T-band photonic transport system using a wavelength tunable light source and an HF transmission line (typically >3.3 km). We successfully developed ultrabroadband transmission capability beyond the 8.4-THz bandwidth (1037-1068 nm), from usable optical frequency resources in the T band. In this band we also successfully demonstrate a polarization division multiplexing (PDM) photonic transport system for achieving efficient use of optical frequency resources. To construct the photonic network system of the future, we believe the technologies of the demonstrated T-band photonic transport systems using the HF transmission line represent a pioneering breakthrough in the use of ultra-broadband optical frequency resources.

In this paper, we demonstrate a computer model for simulating a dual-rate burst mode receiver that can readily distinguish bit rates of 1.25Gbit/s and 10.3Gbit/s and demodulate the data bursts with large power variations of above 5dB. To our knowledge, this is the first such model to demodulate data bursts of different bit rates without using any external control signal such as a reset signal or a bit rate select signal. The model is based on a burst-mode bit rate discrimination circuit (B-BDC) and makes use of a unique preamble sequence attached to each burst to separate out the data bursts with different bit rates. Here, the model is implemented using a combination of the optical system simulation suite OptSim^TM, and the electrical simulation engine SPICE. The reaction time of the burst mode receiver model is about 7ns, which corresponds to less than 8 preamble bits for the bit rate of 1.25Gbps. We believe, having an accurate and robust simulation model for high speed burst mode transmission in GE-PON systems, is indispensable and tremendously speeds up the ongoing research in the area, saving a lot of time and effort involved in carrying out the laboratory experiments, while providing flexibility in the optimization of various system parameters for better performance of the receiver as a whole. Furthermore, we also study the effects of burst specifications like the length of preamble sequence, and other receiver design parameters on the reaction time of the receiver.

We propose a reconfigurable optical add-drop multiplexer with ultra-broadband tuning range over 770 nm using a photorefractive polymer. This add-drop multiplexer can optically switch the assignment of the waveband used for communications by only changing the incident angles of two beams writing a hologram. In this work, we clarified the condition in which the channel tuning can be carried out without the location change in the port array. We simulated on the add-drop operation, and showed the ultra-wide tuning range from 780 to 1550 nm. Moreover, we suggested an apodization method for the grating distribution by controlling the intensity ratio of the writing beams to enhance the diffraction efficiency in add-drop operation. As a result, we showed that the apodization method for the grating distribution can improve the diffraction efficiency.

We describe a novel architecture of broadband ubiquitous femto-cell network with MIMO distributed antenna systems accommodated in WDM-PON. A technical convergence of WDM-PON and time division multiplexed RoF techniques can realize the universality of base stations with various types of broadband air interfaces, the increase of wireless access throughput, and the scalability of service area covered by MIMO distributed antenna systems. We discuss the configuration of MIMO antenna systems, transmission scheme of MIMO RF signals over WDM-PON, and configurations of center station and base stations. The preliminary experiments of proposed network architecture are demonstrated.

We propose an all-optical demultiplexer based on dynamic multiple holograms using a photorefractive material for mode division multiplexing and optical MIMO processing systems. This demultiplexer can separate a specific spatial mode from multiplexed modes in a multi-mode fiber. In this study, we clarify a mode separation performance with various combinations of LP modes, and show the signal-to-noise ratio (SNR) can be improved by choosing appropriate mode combinations. In addition, to reveal the dependence of mode separation of the intensity ratio of the recording lights, we study the fluctuation of the SNR for LP_0,1 mode by the combinations of multiplexed modes. Moreover, two additional recording techniques with a spatial light modulator (SLM) and phase conjugator are also proposed to improve the performance of the mode separation.

This paper focuses on leveraging the progress in semiconductor technologies to facilitate production of efficient light-based in-flight entertainment (IFE), distributed sensing, navigation and control systems. We demonstrate the ease of configuring "engineered pipes" using cheap lenses, etc. to achieve simple linear transmission capacity growth. Investigation of energy-efficient, miniaturized transceivers will create a wireless medium, for both inter and intra aircrafts, providing enhanced security, and improved quality-of-service for communications links in greater harmony with onboard systems. The applications will seamlessly inter-connect multiple intelligent devices in a network that is deployable for aircrafts navigation systems, onboard sensors and entertainment data delivery systems, and high-definition audio-visual broadcasting systems. Recent experimental results on a high-capacity infrared (808 nm) system are presented. The light source can be applied in a hybrid package along with a visible lighting LED for both lighting and communications. Also, we present a pragmatic combination of light communications through "Spotlighting" and existing onboard power-lines. It is demonstrated in details that a high-capacity IFE visible light system communicating over existing power-lines (VLC/PLC) may lead to savings in many areas through reduction of size, weight and energy consumption. This paper addresses the challenges of integrating optimized optical devices in the variety of environments described above, and presents mitigation and tailoring approaches for a multi-purpose optical network.

Integration of next generation wireless technologies i.e., WiMAX (Worldwide Interoperability for Microwave Access) and or LTE (Long Term Evolution) with EPON is a brilliant concept that gives users the best of two worlds, wireless and wired. WiMAX gives users the convenience of mobility while integration with EPON gives theoretically unlimited bandwidth of fiber optic cable in backhaul. This paper investigates WiMAX and EPON technologies. At the end different scenarios of integration of EPON with WiMAX are discussed and optimal QOS mapping scheme is proposed for the integration of EPON and WiMAX.

The presented paper is a techno-economic feasibility study to use solar energy as a renewable energy to power the Passive Optical Network (PON). This discussion focuses on the requirements and sources of power for the active components of optical access networks. To ensure continuous reduction of the carbon footprint while advancing towards purely passive optical networks, we have emphasized the need for alternative, renewable and greener sources to supply the required power. Solar power would be used as the default power source while mains are used as backup or a standby source. This is because solar power can be harvested and stored with less carbon footprint.