Abstract
We present a novel tunable dispersion compensator that can provide pure slope compensation. The approach uses two specially designed complex fiber Bragg gratings (FBGs) with reversely varied third-order group delay curves to generate the dispersion slope. The slope can be changed by adjusting the relative wavelength positions of the two FBGs. Several design examples of such complex gratings are presented and discussed. Experimentally, we achieve a dispersion slope tuning range of +/- 650 ps/nm(2) with > 0.9 nm usable bandwidth.
Highlights
Chromatic dispersion and dispersion slope can cause adverse effects in optical communication systems, and both are especially problematic in high-speed transmission systems since the distortion of the optical signal resulting from chromatic dispersion/slope scales as the square of the signal bandwidth
Tunable dispersion compensators (TDCs) and tunable dispersion slope compensators (TDSCs) are crucial components in advanced high-speed systems, since the dispersion/slope compensation requirements can change due to the signal rerouting in reconfigurable network or even the variation of temperature and strain along fiber link which may degrade the system performance
Dispersion slope problems may be divided into two cases: inter-channel slope and intrachannel slope
Summary
Chromatic dispersion and dispersion slope can cause adverse effects in optical communication systems, and both are especially problematic in high-speed transmission systems since the distortion of the optical signal resulting from chromatic dispersion/slope scales as the square of the signal bandwidth. Intra-channel dispersion slope is where the dispersion experienced by each wavelength component within an optical pulse is different, this distorts the signals within each channel This problem has no significant influence in 10Gb/s system, but needs to be considered when the bit rate reaches 40Gb/s or beyond. To date, reported tunable intrachannel slope compensators are mostly based on FBG devices, such as dynamically applying nonlinear temperature, or nonlinear strain gradient, on a chirped FBG [6,7,8,9,10,11] With these approaches the device itself can have a large chromatic dispersion and/or the dispersion varies simultaneously as the dispersion slope is tuned, so they are not pure TDSCs and contribute additional dispersion compensation [11,12]. The tuning mechanism is very simple (by adjusting the relative wavelength position of the twin FBGs) and no complex temperature or nonlinear strain gradient needs to be generated, such a TDSC has very good reliability and stability
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
