| 1. |
- Karout, Johnny, 1985, et al.
(författare)
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Designing Power-Efficient Modulation Formats for Noncoherent Optical Systems
- 2011
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Ingår i: GLOBECOM - IEEE Global Telecommunications Conference. - 9781424492688
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Konferensbidrag (refereegranskat)abstract
- We optimize modulation formats for the additive white Gaussian noise channel with a nonnegative input constraint, also known as the intensity-modulated direct detection channel, with and without confining them to a lattice structure. Our optimization criteria are the average electrical and optical power. The nonnegativity input signal constraint is translated into a conical constraint in signal space, and modulation formats are designed by sphere packing inside this cone. Some remarkably dense packings are found, which yield more power-efficient modulation formats than previously known. For example, at a spectral efficiency of 1 bit/s/Hz, the obtained modulation format offers a 0.86 dB average electrical power gain and 0.43 dB average optical power gain over the previously best known modulation formats to achieve a symbol error rate of 10^-6. This modulation turns out to have a lattice-based structure. At a spectral efficiency of 3/2 bits/s/Hz and to achieve a symbol error rate of 10^-6, the modulation format obtained for optimizing the average electrical power offers a 0.58 dB average electrical power gain over the best lattice-based modulation and 2.55 dB gain over the best previously known format. However, the modulation format optimized for average optical power offers a 0.46 dB average optical power gain over the best lattice-based modulation and 1.35 dB gain over the best previously known format.
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| 2. |
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| 3. |
- Karout, Johnny, 1985, et al.
(författare)
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Modulation scheme
- 2010
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Annan publikation (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Karout, Johnny, 1985, et al.
(författare)
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Optimizing Constellations for Single-Subcarrier Intensity-Modulated Optical Systems
- 2012
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Ingår i: IEEE Transactions on Information Theory. - 0018-9448 .- 1557-9654. ; 58:7, s. 4645-4659
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Tidskriftsartikel (refereegranskat)abstract
- We optimize modulation formats for the additive white Gaussian noise channel with nonnegative input, also known as the intensity-modulated direct-detection channel, with and without confining them to a lattice structure. Our optimization criteria are the average electrical, average optical, and peak power. The nonnegative constraint on the input to the channel is translated into a conical constraint in signal space, and modulation formats are designed by sphere packing inside this cone. Some dense packings are found, which yield more power-efficient modulation formats than previously known. For example, at a spectral efficiency of 1.5 bit/s/Hz, the modulation format optimized for average electrical power has a 2.55 dB average electrical power gain over the best known format to achieve a symbol error rate of 10-6 . The corresponding gains for formats optimized for average and peak optical power are 1.35 and 1.72 dB, respectively. Using modulation formats optimized for peak power in average-power limited systems results in a smaller power penalty than when using formats optimized for average power in peak-power limited systems. We also evaluate the modulation formats in terms of their mutual information to predict their performance in the presence of capacity-achieving error-correcting codes, and finally show numerically and analytically that the optimal modulation formats for reliable transmission in the wideband regime have only one nonzero point.
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| 5. |
- Szczerba, Krzysztof, 1985, et al.
(författare)
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30 Gbps 4-PAM transmission over 200m of MMF using an 850 nm VCSEL
- 2011
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 19:26, s. B203-B208
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Tidskriftsartikel (refereegranskat)abstract
- We present high speed real time, error free 4-PAMtransmissionfor short range optical links based on a VCSEL operating at 850 nm, a multimode fibre and a simple intensity detector. Transmission speeds of 25 Gbps and 30 Gbps are demonstrated, and the maximum fibre reaches were 300 m and 200 m, respectively. The 4-PAM is also compared with OOK transmission at 25 Gbps, and we find that at this bit rate 4-PAM increases the error free transmission distance in the multimode fibre by 100 m, compared to OOK.
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| 6. |
- Szczerba, Krzysztof, 1985, et al.
(författare)
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30 Gbps 4-PAM transmission over 200m of MMF using an 850 nm VCSEL
- 2011
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Ingår i: European Conference and Exposition on Optical Communications, ECOC. - 2162-2701. - 9781557529312 ; , s. 1-3
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Konferensbidrag (refereegranskat)abstract
- Real time, error free 4-PAM transmission at 25 Gbps and 30 Gbps over 300 m and200m of multimode fiber, respectively, using a VCSEL operating at the wavelength of 850 nm.
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| 7. |
- Szczerba, Krzysztof, 1985, et al.
(författare)
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4-PAM for high-speed short-range optical communications
- 2012
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Ingår i: Journal of Optical Communications and Networking. - 1943-0620 .- 1943-0639. ; 4:11, s. 885-894
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we compare 4-pulse amplitudemodulation and on–off keying modulation formats at highspeed for short-range optical communication systems. Thetransmission system comprised a directly modulated verticalcavitysurface-emitting laser operating at a wavelength of850 nm, an OM3Å multimode fiber link, and a photodetectordetecting the intensity at the receiver end. The modulationformats were compared both at the same bit-rate and at thesame symbol rate. The maximum bit-rate used was 25 Gbps.Propagation distances up to 600 m were investigated at12.5 Gbps. All measurements were done in real time andwithout any equalization.
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| 8. |
- Szczerba, Krzysztof, 1985, et al.
(författare)
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Demonstration of 8-level subcarrier modulation sensitivity improvement in an IM/DD system
- 2011
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Ingår i: European Conference and Exposition on Optical Communications, ECOC. - Washington, D.C. : OSA. - 2162-2701. - 9781557529312 - 9781557529312
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Konferensbidrag (refereegranskat)abstract
- We experimentally demonstrate up to 2 dB sensitivity improvement for 8-levelsubcarrier modulation compared to conventional 8-level subcarrier modulation.
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| 9. |
- Szczerba, Krzysztof, 1985, et al.
(författare)
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Experimental comparison of modulation formats in IM/DD links
- 2011
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 19:10, s. 9881-9889
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Tidskriftsartikel (refereegranskat)abstract
- We present an experimental comparison of modulation formatsfor optical intensity modulated links with direct detection. Specifically, wecompare OOK, QPSK on an electrical subcarrier and a new modulationformat named OOPSK. The OOPSK modulation format is shown to havebetter sensitivity than the other modulation formats, in agreement withtheoretical predictions. The impact of propagation in multimode fiber isalso studied and the results show that all modulation formats have similarsensitivity penalties, with respect to the fibre length.
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| 10. |
- Szczerba, Krzysztof, 1985, et al.
(författare)
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Optimized lattice-based 16-level subcarrier modulation for IM/DD systems
- 2012
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Ingår i: 2012 38th European Conference and Exhibition on Optical Communications, ECOC 2012; Amsterdam; Netherlands; 16 September 2012 through 20 September 2012. - 9781557529503 ; , s. Art. no. 6705904-
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Konferensbidrag (refereegranskat)abstract
- We present an experimental demonstration of an optimized 16-level lattice-based single-cycle subcarrier modulation for IM/DD systems at 10 Gbps. The new format has 2.5 dB better sensitivity than single-cycle subcarrier 16-QAM and up to 1 dB better sensitivity than baseband 4-PAM at the same bit rate.
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