Performance demonstration of 300-km dispersion uncompensated transmission using tunable chirp-managed laser and EDC integratable into small-form-factor MSAs

Abstract

We demonstrate 300-km transmission of 10Gb/s data over SMF-28 fiber without DCF using a 4-channel tunable chirp managed laser and EDC chip at the receiver, which can fit into hot pluggable XFP modules. IntroductionThe recent increase in number of populated 10 Gb/s WDM channels in metro and regional networks has increased demand for tunable, small footprint and low power consumption transmitters in order to reduce costs of inventory management and simplify network complexity. Concurrently the upgrade of WDM systems from 2.5 Gb/s to 10 Gb/s for metro networks spanning up to 200km has benefited from dispersion tolerant transmitter technologies such as optical duobinary [1] and chirp managed laser [2], since they eliminate dispersion compensation modules. Tunable externally modulated LiNbO 3 duobinary transmitters can reach 200 km in standard single-mode fiber (SMF) at 1550 nm window but are not suitable for XFP transceivers because they are too bulky and too power hungry. Compact multiple quantum-well InP Mach-Zehnder (MZ) modulator tunable transmitters are promising because of their smaller size. They can reach 100 km using standard laser drivers [3] and 200 km using the duobinary configuration [4]. However, adding a second high performance InP MZ chip will increase the cost and complexity of the module. Furthermore, the additional insertion loss of the InP MZ and the drive voltage requirements may be prohibitive in many applications. Chirp managed laser (CML) provides high optical output power, long transmission distance in standard single-mode fibers. In addition, this new transmitter requires a low driving voltage and, by eliminating the external modulator offers a reduced footprint, which fits into a small form factor XFP TOSA (Transmitter Optical Sub-Assembly) package.In the receive side, the last several years have witnessed the introduction and commercialization of FFE/DFEbased EDC techniques for intersymbol interference (ISI) mitigation in optical networks [5]. The FFE (feed-forward equalizer) combined with DFE (decision-feedback equalizer) realized within one IC provides a rational balance between good performance and additional aspects that have to be considered for modular applications: i.e., size, power consumption and cost. In addition, the FFE/DFE based EDC receivers have been implemented with a "setand-forget" type of self-adaptive algorithm to avoid any costly system adjustments. Being low power, small size and self-adaptive, the EDC receiver is easily embedded in small-form MSAs such as hot pluggable XFP transceivers, Xenpak/X2 or small-form-factor 300-pin transponders for enhanced system performance. Currently the EDC technology has started volume deployment largely in the enterprise area, and will soon enter into the metro, regional and long-haul networks [6][7].In this paper, we demonstrate a 4-channel tunable TOSA module based on CML technology with +1 to +3 dBm average output power. Error-free transmission performance at 10.7 Gb/s up to 200 km without EDC or optical dispersion compensation is ...