Title :
70 Gbps 4-PAM and 56 Gbps 8-PAM Using an 850 nm VCSEL
Author :
Szczerba, Krzysztof ; Westbergh, Petter ; Karlsson, Magnus ; Andrekson, Peter A. ; Larsson, Anders
Author_Institution :
Dept. of Microtechnol. & Nanosci., Chalmers Univ. of Technol., Goteborg, Sweden
Abstract :
We present 56 Gbps unequalized 8-pulse-amplitude-modulation (PAM) real-time transmission over 50 m of multimode fiber and 70 Gbps 4-PAM operation with offline equalization. FEC would be necessary in both schemes. The bit-rates are given taking into account the FEC overhead needed to reach a BER below 10-12. The experiments were performed with an 850 nm vertical cavity surface emitting laser with 20 GHz bandwidth and a 22 GHz photoreceiver. We show that 8-PAM modulation requires channel bandwidth comparable with the symbol rate to avoid excessive ISI penalty and that equalization of 4-PAM signal can significantly improve achievable bit-rates.
Keywords :
error statistics; forward error correction; interference suppression; intersymbol interference; light interference; microwave receivers; optical fibre communication; optical modulation; optical receivers; pulse amplitude modulation; surface emitting lasers; wireless channels; BER; FEC overhead; PAM real-time transmission; PAM signal equalization; VCSEL; bandwidth 20 GHz; bandwidth 22 GHz; bit error rate; bit rate 56 Gbit/s; bit rate 70 Gbit/s; channel bandwidth; excessive ISI penalty avoidance; intersymbol interference; multimode fiber; offline equalization; photoreceiver; pulse amplitude modulation; size 50 m; size 850 nm; vertical cavity surface emitting laser; Bandwidth; Bit error rate; Equalizers; Forward error correction; Frequency response; Modulation; Vertical cavity surface emitting lasers; 4-PAM; 8-PAM; 850 nm; Data communications; IM/DD; MMF; OOK; VCSEL; data communications; equalization; fiber-optical communications; interconnects; intersymbol interference; short-range;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2015.2389898
