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- Chughtai, Mohsan Niaz, et al.
(författare)
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Analysis of Non-Linear Impairments in 40 Gbaud PM DQPSK and D8PSK Transmission
- 2010
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Ingår i: ICTON 2010. - : IEEE Press. - 9781424477982 ; , s. 1 -4
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Konferensbidrag (refereegranskat)abstract
- In this paper, 40 Gbaud transmission of single polarization (SP) and Polarization-Multiplexed (PM), RZ-DQPSK and RZ-D8PSK signals is analyzed numerically. The impact of nonlinear crosstalk arising from the presence of neighbouring intensity-modulated channels is analyzed in terms of required OSNR for the BER of 10-3versus launch power.
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| 2. |
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| 3. |
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| 4. |
- Forzati, Marco, 1975
(författare)
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Phase Modulation Techniques for On-Off Keying in Optical Fibre Transmission.
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Increasing the channel bit rate is an efficient way to upgrade traffic capacity in installed transmission links. At bit rates of the order of 40 Gb/s, on-off keying (OOK) transmission becomes severely impaired by non-linear effects especially Intra-channel Four-Wave Mixing (IFWM) which limit the power at which the signal can be transmitted, and ultimately the transmission distance.This thesis introduces new techniques for the suppression of IFWM. In the modulation formats Alternate-Phase Return-to-Zero (APRZ) and Pairwise APRZ (PAPRZ), the phase of the optical signal alternates between neighbouring bits or pairs of bits. APRZ and PAPRZ achieve increased non-linear tolerance by causing different IFWM contributions to interfere destructively, when proper phase-alternation amplitude is applied. In another technique, Asynchronous Phase Modulation (APM), the phase of the optical signal is modulated by an independent clock signal, at a frequency lower than the bit rate. APM achieves increased non-linear tolerance by a combination of destructive interference of IFWM contributions and suppression of the frequency-matching condition for the build-up of IFWM, when phase modulation with proper amplitude and frequency is applied.The techniques are studied analytically and by means of numerical simulations, and their properties are verified with transmission experiments, both in the laboratory and in installed transmission systems. It is shown that APRZ and PAPRZ can achieve a significant improvement in power tolerance, compared with currently used OOK modulation formats. It is also shown that APM can successfully increase the power tolerance of OOK transmission using standard modulation formats with low implementation cost such as RZ and NRZ. A patent has been granted for a generalisationof the PAPRZ scheme, and a patent application has been filed for the APM scheme.
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| 5. |
- Forzati, Marco, 1975
(författare)
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The alternate-phase return-to-zero modulation format in high-speed optical-fibre communications
- 2006
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Increasing the channel bit rate is an efficient way to upgrade traffic capacity in installed transmission links. At bit rates of the order of 40 Gb/s, on-off keying transmission becomes severely impaired by non-linear effects,particularly Intra-channel Cross-Phase Modulation (IXPM) and Intra-channel Four-Wave Mixing (IFWM), which cause pulses in different bit slots to interact with each-other.IFWM is a phase sensitive process and can therefore be suppressed by proper phase modulation of the optical signal. This thesis introduces a new modulation format, called Alternate-Phase Return-to-Zero (APRZ), in which the phase of the optical signal alternates between neighbouring pulses. A variation of APRZ-Pairwise APRZ (PAPRZ) - is also studied. Theoretical analysis shows that a proper choice of the phase-modulation amplitude can make IFWM contributions coming from different pulse combinations to interfere destructively, therefore reducing the impact of IFWM.The theoretical predictions are verified through numerical simulations and laboratory experiments. It is shown that APRZ and PAPRZ can achieve a significant improvement in non-linear tolerance, compared to the standard return-to-zero (RZ) transmission format.
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| 6. |
- Tipsuwannakul, Ekawit, 1982, et al.
(författare)
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Influence of self- and cross-phase modulation on 40 Gbaud dual polarization DQPSK/D8PSK signals in 10 Gbit/s OOK WDM systems
- 2010
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087 .- 1094-4087. ; 18:23, s. 24178-24188
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Tidskriftsartikel (refereegranskat)abstract
- This paper, for the first time, investigates the nonlinear degradation of 40 Gbaud single- and dual polarization RZ-DQPSK/D8PSK signals caused by SPM and XPM-induced crosstalk from neighboring 10 Gbit/s NRZ-OOK channels in an WDM upgrade scenario. The investigations were numerically and experimentally conducted over a 320 km transmission link with three different wavelength configurations to address the impact of the walk-off length. The paper also presents the first numerical analysis of the XPM dependence on the relative state of polarization of the D8PSK with respect to the neighbors. © 2010 Optical Society of America.
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