Characterization of wavelength interleaving in radio-over-fiber systems employing WDM/SCM

A radio-over-fiber (RoF) distribution system incorporating both sub-carrier multiplexing and wavelength division multiplexing (WDM) technologies is presented. This signal is directly modulated onto three high-speed lasers. Bragg filters are employed at the receiver base station in order to both demultiplex the required optical channel, and ensure that the detected signal is single side band (in order to overcome dispersion limitations of the link). System spectral efficiency is optimised by wavelength interleaving. The channel spacing between the WDM channels is varied and the system performance for different values of channel spacing and spectral efficiencies is investigated. The results show that wavelength interleaving is a reliable technique that could be used to increase the spectral efficiency of RoF systems

Cost efficient narrow linewidth laser transmitter for coherent detection

Authors present a cost efficient narrow linewidth laser transmitter for future coherent detection systems. The spectral purity of the laser allows the phase modulation of data signals at bit rates as low as 155 Mb/s

Optimized pulse source based on a gain-switched laser diode in conjuction with a non-linearly chirped grating for 40 Gbit/s systems

A technique based on the design of an optimized source of pico-second optical pulses, which exhibits excellent temporal and spectral purity, is presented. The procedure entails an initial complete intensity and chirp characterization of pulses, from an externally injected-gain switched laser (EI-GSL), using the technique of frequency resolved optical gating (FROG). This characterization yields the parameters that are required for the design of a non-linearly chirped fibre Bragg grating (NC FBG) with a chirp profile that is opposite to that measured across the pulse. By employing the tailor made NC FBG after the gain-switched laser, direct compression of the gain-switched pulses is achieved, to obtain pedestal-free, near transform-limited, 7 ps pulses. The system viability, characterized by simulations, portrays a 6 dB difference in performance between a pulse source with insufficient TPSR and one that exhibits adequate TPSR &(ge; 30 dB)

Performance Issues Associated With WDM Optical Systems Using Self-Seeded Gain Switched Pulse Sources Due to Mode Partition Noise Effects

Abstract-Bit-error-rate measurements have been carried out on a four-channel wavelength division multiplexed setup using tunable self-seeded gain-switched pulse sources. These measurements demonstrate the degradation in overall system performance, due to mode partition noise, as the sidemode suppression ratio of the self-seeded gain-switched optical pulse sources is reduced. The results also show that the constraints on the minimum sidemode suppression ratio required increase with the number of channels in the system. Index Terms-Optical fiber communications, optical pulse generation, mode partition noise, semiconductor laser, wavelength-division multiplexing

Microresonator-based spectral translation of a gain-switched semiconductor laser comb

Abstract not availableWenle Weng, Aleksandra Kaszubowska-Anandarajah, Prince M. Anandarajah, and Andre N. Luite

Microresonator Dissipative Kerr Solitons Synchronized to an Optoelectronic Oscillator

Using phase-modulation-induced potential gradient whose period is synchronized to a microwave optoelectronic oscillator, dissipative Kerr solitons generated in a crystalline optical microresonator are trapped by the soliton tweezing effect, exhibiting a stabilized soliton repetition rate. In the meantime, side-mode suppression of the microwave signal is enabled by the photodetection of the soliton train. Substantiated both experimentally and theoretically, the hybrid system produces a drift-reduced microcomb and a spectrum-purified optoelectronic oscillator simultaneously, yielding a low-cost toolkit for microwave and optical metrology.Wenle Weng, Jijun He, Aleksandra Kaszubowska-Anandarajah, Prince M. Anandarajah, and Tobias J. Kippenber

A Survey of Optical Carrier Generation Techniques for Terabit Capacity Elastic Optical Networks

Elastic optical networks (EON) have been proposed to meet the network capacity and dynamicity challenges. Hardware and software resource optimization and re-configurability are key enablers for EONs. Recently, innovative multi-carrier transmission techniques have been extensively investigated to realize high capacity (Tb/s) flexible transceivers. In addition to standard telecommunication lasers, optical carrier generators based on optical frequency combs (OFC) have also been considered with expectations of reduced cost and inventory, improved spectral efficiency, and flexibility. A wide range of OFC generation techniques have been proposed in the literature over the past few years. It is imperative to summarize the state of the art, compare and assess these diverse techniques from a practical perspective. In this survey, we identify salient features of optical multicarrier generators, review and compare these techniques both from a physical and network layer perspective. OFC demultiplexing/filtering techniques have also been reviewed. In addition to transmission performance, the impact of such sources on the network performance and real-world deployment strategies with reference to cost, power consumption, and level of flexibility have also been discussed. Field trials, integrated solutions, and flexibility demonstrations are also reported. Finally, open issues and possible future directions that can lead to real network deployment are highlighted