Advanced modulation formats for short-range optical communications
Licentiate thesis, 2011

The demand for faster short range optical links is increasing and simple modulation techniques, such as on-o keying do not scale well to higher data rates, because of the limited bandwidth-distance product of the multimode ber. The industry has responded to this problem by aggregating multiple parallel links operating at lower bit-rate. Another possible way of improving the short range optical interconnect is to used better, more advanced modulation formats. Advanced modulation formats in the context of short range optical communication are the topic of this thesis. A broad spectrum of modulation formats have been studied, starting with pulse amplitude modulation, through conventional subcarrier modulation, to a new class of three-dimensional subcarrier modulation. Although these modulation formats are very diverse, they also have one aspect in common; they can be implemented in systems using intensity modulation and direct detection. The modulation formats were investigated experimentally in an optical link using a directly modulated vertical cavity surface emitting laser as a transmitter, photodiode for direct detection in the receiver and multimode ber as the transmission medium. The relatively simple pulse amplitude modulation was the easiest one to implement at high bit-rates; 30 Gbps error free real time transmission was demonstrated. The subacarrier modulation is more complex and required o-line signal processing, however operation at bit-rates as high as 37 Gbps were demonstrated. Finally, modulation formats for IM/DD links with improved sensitivity were investigated, showing 0.6 dB better sensitivity and the same spectral efficiency as OOK. More complex format with 8 levels and 2 dB better sensitivity than subcarrier 8-QAM was also demonstrated.

Kollektorn, Kemivägen 9
Opponent: dr. Jonas Hansryd


Krzysztof Szczerba

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

30 Gbps 4-PAM transmission over 200m of MMF using an 850 nm VCSEL

Optics Express,; Vol. 19(2011)p. B203-B208

Journal article

37 Gbps transmission over 200 m of MMF using single cycle subcarrier modulation and a VCSEL with 20 GHz modulation bandwidth

2010 36th European Conference and Exhibition on Optical Communication (ECOC),; Vol. 1-2(2010)p. 1-3

Paper in proceedings

Experimental comparison of modulation formats in IM/DD links

Optics Express,; Vol. 19(2011)p. 9881-9889

Journal article

Demonstration of 8-level subcarrier modulation sensitivity improvement in an IM/DD system

European Conference and Exposition on Optical Communications, ECOC,; (2011)

Paper in proceedings

4-PAM for high-speed short-range optical communications

Journal of Optical Communications and Networking,; Vol. 4(2012)p. 885-894

Journal article

Areas of Advance

Information and Communication Technology

Subject Categories


Technical report MC2 - Department of Microtechnology and Nanoscience, Chalmers University of Technology: 209

Kollektorn, Kemivägen 9

Opponent: dr. Jonas Hansryd

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