| 11. |
- Sjödin, Martin E, 1983, et al.
(författare)
-
Comparison of polarization-switched QPSK and polarization-multiplexed QPSK at 30 Gbit/s
- 2011
-
Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 19:8, s. 7839-7846
-
Tidskriftsartikel (refereegranskat)abstract
- We present the first experimental results for polarization-switched QPSK (PS-QPSK) and make a comparison with polarization-multiplexed QPSK. Our measurements confirm the predicted sensitivity advantage of PS-QPSK. We have also studied the single channel performance after transmission over 300 km and support the results with numerical simulations. It is shown that the two modulation formats have similar nonlinear tolerance and that optical dispersion compensation outperforms compensation with digital signal processing in the single channel case. Finally, we propose a novel transmitter for PS-QPSK based on an IQ modulator and two amplitude modulators driven in a push-pull configuration.
|
|
| 12. |
- Sjödin, Martin E, 1983, et al.
(författare)
-
Filter Optimization for Self-Homodyne Coherent WDM Systems using Interleaved Polarization Division Multiplexing
- 2011
-
Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 29:9, s. 1219 - 1226
-
Tidskriftsartikel (refereegranskat)abstract
- We examine the impact of filtering on self-homodynecoherent WDM systems using the interleaved polarization division multiplexing scheme. To investigate the performance limit and to provide more insight into previously obtained experimental results we perform numerical simulations in which different filter shapes and filter bandwidths are used. It is shown that with proper prefiltering of the data and filtering of the pilot tone in the receiver, performance can approach that of an intradyne system, which would make it possible to implement coherent systems with high spectral efficiency without any digitalsignal processing in the receiver.
|
|
| 13. |
- Sjödin, Martin E, 1983, et al.
(författare)
-
Interleaved Polarization Division Multiplexing in Self-Homodyne Coherent WDM Systems
- 2010
-
Ingår i: Proceedings of European Conference on Optical Communication, ECOC 2010, Turin, Italy, September 19-23, 2010. - 9781424485352 ; 1-2
-
Konferensbidrag (refereegranskat)abstract
- We demonstrate increased spectral efficiency for self-homodyne coherent WDM systems by using a novel interleaved polarization division multiplexing scheme.
|
|
| 14. |
- Sjödin, Martin E, 1983, et al.
(författare)
-
Measurement of the Phase Noise Tracking Capability of a Digital Coherent Receiver
- 2011
-
Ingår i: European Conference and Exposition on Optical Communications, ECOC 2011; Geneva; Switzerland; 18 September 2011 through 22 September 2011. - 2162-2701. - 9781557529312
-
Konferensbidrag (refereegranskat)abstract
- We present a method to evaluate the phase noise tracking performance of a digital coherent receiver. Measurements of the phase error variance of QPSK at different symbol rates are presented for two different algorithms.
|
|
| 15. |
- Tan, Ahmet Serdar, 1982, et al.
(författare)
-
An ML-based Detector for Optical Communication in the Presence of Nonlinear Phase Noise
- 2011
-
Ingår i: IEEE International Conference on Communications. - : IEEE. - 1550-3607. - 9781612842332 ; , s. Art. no. 5962741-
-
Konferensbidrag (refereegranskat)abstract
- We present a closed-form maximum likelihood-based data detection algorithm for long-haul optical channels with dominant nonlinear phase noise induced by self-phase modulation. The closed-form detector is evaluated in terms of symbol error rate as a function of input power, and compared with other sub-optimal detectors as well as a non-parametric detector. We show that the performance of the detector deteriorates for high input power levels, resulting in an optimal operation region. We also provide insights into the behavior of the detector in the highly nonlinear regime.
|
|
| 16. |
- Tan, Ahmet Serdar, 1982, et al.
(författare)
-
Modified Cramer-Rao Bound for Clock Recovery in the Presence of Self-Phase Modulation
- 2012
-
Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 30:16, s. 2556-2562
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the effect of nonlinear self-phase modulation (SPM) on clock recovery in long-haul coherent optical communication systems with low to moderate baud rates. We consider dual-polarization, multilevel quadrature amplitude modulation, and evaluate conventional timing estimators as well as a modified Cramer-Rao bound. As the latter is hard to compute in the presence of nonlinear channel impairments, we derive an approximate closed-form expression. Contrary to linear channel impairments, the nonlinear impairments can degrade the performance for higher input powers. In addition, the bounds exhibit oscillatory behavior due to the oscillations in the signal spectrum in the presence of SPM.
|
|
| 17. |
- Tan, Ahmet Serdar, 1982, et al.
(författare)
-
The Impact of Self-Phase Modulation on Digital Clock Recovery in Coherent Optical Communication
- 2010
-
Ingår i: Proceedings of European Conference on Optical Communication, ECOC 2010, Turin, Italy, September 19-23, 2010. - 9781424485352 ; 1-2
-
Konferensbidrag (refereegranskat)abstract
- The impact of self-phase modulation on the estimation error variance of digital clock recovery schemes for coherent 16-QAM dual-polarization systems is investigated. The error variance increases severely compared to the linear case and the theoretical bounds.
|
|
| 18. |
- Eliasson, Henrik, 1985, et al.
(författare)
-
Transmitter mask testing for 28 GBaud PM-QPSK
- 2013
-
Ingår i: Optical Communication (ECOC 2013), 39th European Conference and Exhibition on. - : Institution of Engineering and Technology. - 9781849197595 ; 2013, s. 282 - 284
-
Konferensbidrag (refereegranskat)abstract
- We suggest a method for pass/fail testing of PM-QPSK transmitters. The test is based on mask testing with time-resolved EVM and accepts transmitters where individual impairments cause less than 0.5 dB OSNR penalty. The design of the test is performed by computer simulations followed by experimental verification of some key results.
|
|
| 19. |
- Eriksson, Tobias, 1986, et al.
(författare)
-
Biorthogonal modulation in 8 dimensions experimentally implemented as 2PPM-PS-QPSK
- 2014
-
Ingår i: Optical Fiber Communication Conference, OFC 2014. - Washington, D.C. : OSA. - 9781557529930 ; , s. Art. no. 6886984-
-
Konferensbidrag (refereegranskat)abstract
- We experimentally demonstrate biorthogonal modulation in 8 dimensions as binary pulse-position modulation polarization-switched QPSK. We compare this format with PM-QPSK at the same bit rate and show a 1.4 dB sensitivity gain and 84 % increased transmission distance.
|
|
| 20. |
- Eriksson, Tobias, 1986, et al.
(författare)
-
Comparison of 128-SP-QAM and PM-16QAM in long-haul WDM transmission
- 2013
-
Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 21:16, s. 19269-19279
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate 128-level set-partitioning quadrature amplitude modulation (128-SP-QAM) experimentally and compare the performance to polarization-multiplexed 16QAM both at the same bit rate and at the same symbol rate. Using a recirculating loop we study both single channel and wavelength-division multiplexing (WDM) transmission and demonstrate a reach of up to 2680 km at a bit-error rate of 10−3 for 128-SP-QAM. We confirm that 128-SP-QAM has an increased sensitivity compared to PM-16QAM and show that the maximum transmission distance can be increased by more than 50 % at the same bit rate for both single channel and WDM transmission. We also investigate the performance at the same symbol rate as a possible fall back solution in a degrading link.
|
|
