Influence of Fiber-Bragg Grating-Induced Group-Delay Ripple in High-Speed Transmission Systems
Journal article, 2012

The implementation of a chirped fiber-Bragg grating (FBG) for dispersion compensation in high-speed (up to 120 Gbit/s) transmission systems with differential and coherent detection is, for the first time, experimentally investigated. For systems with differential detection, we examine the influence of group-delay ripple (GDR) in 40 GBd 2-, 4-, and 8-ary differential phase shift keying (DPSK) systems. Furthermore, we conduct a nonlinear-tolerance comparison between the systems implementing dispersion-compensating fibers and FBG modules, using a 5 x 80 Gbit/s 100-GHz-spaced wavelength division multiplexing 4-ary DPSK signal. The results show that the FBG-based system provides a 2 dB higher optimal launch power, which leads to more than 3 dB optical signal-to-noise ratio (OSNR) improvement at the receiver. For systems with coherent detection, we evaluate the influence of GDR in a 112 Gbit/s dual-polarization quadrature phase shift keying system with respect to signal wavelength. In addition, we demonstrate that, at the optimal launch power, the 112 Gbit/s systems implementing FBG modules and that using electronic dispersion compensation provide similar performance after 840 km transmission despite the fact that the FBG-based system delivers lower OSNR at the receiver. Lastly, we quantify the GDR mitigation capability of a digital linear equalizer in the 112 Gbit/s coherent systems with respect to the equalizer tap number (N-tap). The results indicate that at least N-tap = 9 is required to confine Q-factor variation within 1 dB.

Differential detection

Coherent detection

dispersion compensation

Fiber Bragg


Dispersion compensation


Ekawit Tipsuwannakul

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Jianqiang Li

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Tobias Eriksson

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

L. Egnell

Proximion AB

F. Sjostrom

Proximion AB

J. Pejnefors

Proximion AB

Peter Andrekson

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Magnus Karlsson

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Journal of Optical Communications and Networking

1943-0620 (ISSN) 19430639 (eISSN)

Vol. 4 6 514-521 6226978

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