Video Service Delivery Over a Repeater-Based Optical Access Network

A low-cost and bandwidth-efficient scheme for delivering video services to customers over a long reach, large split repeater-based optical access network is proposed and experimentally demonstrated. Video channels that are on radio-frequency subcarriers are electrically combined with regenerated downstream data at the repeater and delivered to the customers on a single wavelength channel. Experimental results show that error-free transmission can be obtained for all channels with adequate power budget to support a split ratio more than 64.     

Generation and Separation of Closely Separated Dual Baseband Channels for Provisioning of Independent Services in WDM-PON

This letter presents a novel technique that enables simple provisioning of independent services in wavelength-division-multiplexed passive optical networks. The technique uses a single laser and modulator for generation and a periodic passive filter for separation of two closely separated baseband channels. We present experimental results of the bit-error-rate performance for the two 1.5-Gb/s independent service channels at a frequency separation of only 6 GHz.     

On the merging of millimeter-wave fiber-radio backbone with 25-GHz WDM ring networks

We present an optical modulation and distribution scheme that incorporates subcarrier-multiplexed (SCM) transport with remote local oscillator (LO) delivery for a millimeter-wave (mm-wave) fiber-radio backbone driving a sectorized antenna interface. The proposed method is compatible with a standard wavelength-division multiplexing infrastructure with a 25-GHz channel spacing. We also characterize the profiles and bandwidths of the optical filters, which are essential for the adding and dropping of the 25-GHz signal block and the optical extraction of the LO signal. The placement of the LO signal within the 25-GHz band is investigated and its effect on the filter bandwidth requirements and system performance quantified. The performance of a ring incorporating the distribution scheme is evaluated via simulation. It is established that a compromise must be made between the feasibility of the required filters and the incurred penalty due to intermodulation distortions from adjacent blocks.     

Generation of 140 GHz optical pulses with suppressed amplitudemodulation by subharmonic synchronous modelocking of Fabry-Perotsemiconductor laser

140 GHz optical pulses with a pulsewidth of 2.7 ps are generated from a standard Fabry-Perot semiconductor laser using subharmonic optical injection. A new technique based on optical feed forward modulation is also presented to suppress the amplitude modulation associated with subharmonic injection     

Subharmonic synchronous and hybrid mode-locking of a monolithic DBR laser operating at millimeter-wave frequencies

A detailed comparison of subharmonic synchronous and subharmonic hybrid mode-locking of a monolithic distributed Bragg reflector (DBR) laser operating at 33 GHz is presented. Optical injection at the 20th subharmonic frequency (1.65 GHz) has produced a locking range of 10 MHz with negligible amplitude modulation. In comparison, electrical injection at the 4th subharmonic frequency (5.83 GHz) has shown higher levels of amplitude modulation and a narrower locking range (4 MHz). While subharmonic hybrid mode-locking remains a simple and cost effective solution for the generation of low timing jitter high-repetition rate optical pulse trains, subharmonic synchronous mode-locking shows superior performance with regard to reduced amplitude modulation and larger locking range.     

Packet labeling technique using electronic code-division multiple-access for WDM packet-based access networks

We propose and experimentally demonstrate the feasibility of a packet labeling technique using electronic code-division multiple-access for a wavelength-division-multiplexing (WDM) packet-based access network, whereby each wavelength is assigned a unique electronic code-based label on a radio-frequency subcarrier. Such a technique allows individual wavelength channels to be electronically identified without requiring the use of a WDM demultiplexer. We experimentally demonstrate this technique with two WDM channels each with 1.25-Gb/s payload data and 10-Mb/s header coded onto an electronic code at 160 Mb/s. The experimental results and theoretical analysis show that this technique has the potential to support large numbers of WDM channels.     

An Efficient Resource Allocation Mechanism for LTE–GEPON Converged Networks

Optical–wireless convergence is becoming popular as one of the most efficient access network designs that provides quality of service (QoS) guaranteed, uninterrupted, and ubiquitous access to end users. The integration of passive optical networks (PONs) with next-generation wireless access networks is not only a promising integration option but also a cost-effective way of backhauling the next generation wireless access networks. The QoS performance of the PON–wireless converged network can be improved by taking the advantages of the features in both network segments for bandwidth resources management. In this paper, we propose a novel resource allocation mechanism for long term evolution–Gigabit Ethernet PON (LTE–GEPON) converged networks that improves the QoS performance of the converged network. The proposed resource allocation mechanism takes the advantage of the ability to forecast near future packet arrivals in the converged networks. Moreover, it also strategically leverages the inherited features and the frame structures of both the LTE network and GEPON, to manage the available bandwidth resources more efficiently. Using extensive simulations, we show that our proposed resource allocation mechanism improves the delay and jitter performance in the converged network while guarantying the QoS for various next generation broadband services provisioned for both wireless and wired end users. Moreover, we also analyze the dependency between different parameters and the performance of our proposed resource allocations scheme.     

Dispersion-induced power penalties in millimeter-wave signaltransmission using multisection DBR semiconductor laser

In this paper, we present a simple analytical model to characterize the effect of fiber chromatic dispersion when using a multisection distributed-Bragg reflector (DBR) semiconductor laser as a millimeter-wave optical transmitter in a millimeter-wave fiber-radio system. We characterize the dispersion penalty of the laser as a function of the laser operating conditions and establish that the penalty is dependent on the distribution of optical power among the modes in the laser output. This, in turn, is dependent on the spectrum-filtering property of the laser DBR section and the gain profile of the laser. In addition to the dispersion penalty, the stability of the generated millimeter-wave carrier from the multisection laser is investigated, including the detected RF power and resulting phase noise. We establish that a compromise must be made when finding the optimum bias condition of the laser which provides minimum dispersion penalty, maximum received RF power, and minimum phase noise of the generated millimeter-wave carrier     

Novel schemes for local area network emulation in passive optical networks with RF subcarrier multiplexed customer traffic

This paper proposes two novel optical layer schemes for intercommunication between customers in a passive optical network (PON). The proposed schemes use radio frequency (RF) subcarrier multiplexed transmission for intercommunication between customers in conjunction with upstream access to the central office (CO) at baseband. One scheme employs a narrowband fiber Bragg grating (FBG) placed close to the star coupler in the feeder fiber of the PON, while the other uses an additional short-length distribution fiber from the star coupler to each customer unit for the redirection of customer traffic. In both schemes, only one optical transmitter is required at each optical network unit (ONU) for the transmission of customer traffic and upstream access traffic. Moreover, downstream bandwidth is not consumed by customer traffic unlike in previously reported techniques. The authors experimentally verify the feasibility of both schemes with 1.25 Gb/s upstream baseband transmission to the CO and 155 Mb/s customer data transmission on the RF carrier. The experimental results obtained from both schemes are compared, and the power budgets are calculated to analyze the scalability of each scheme. Further, the proposed schemes were discussed in terms of upgradability of the transmission bit rates for the upstream access traffic, bandwidth requirements at the customer premises, dispersion tolerance, and stability issues for the practical implementations of the network.     

Self-protected Ethernet passive optical networks using coarse wavelength division multiplexed transmission

Proposed and experimentally demonstrated is a novel self-protected architecture for Ethernet passive optical networks. The protection of the traffic transported between the central office and customer terminals against feeder fibre cable breaks is carried out by switching and overlaying the disrupted transmission channels onto a separate Ethernet passive optical network using waveband separation.