| 271. |
- Lorences Riesgo, Abel, 1987, et al.
(författare)
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Phase-Sensitive Amplification and Regeneration of Dual-Polarization BPSK without Polarization Diversity
- 2014
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Ingår i: 2014 European Conference on Optical Communication, ECOC 2014; Cannes; France; 21 September 2014 through 25 September 2014. - 9782954944401 ; , s. Art. no. 6964045-
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Konferensbidrag (refereegranskat)abstract
- We analyze the performance of a degenerate vector PSA-based receiver and compare to an EDFA-based receiver, achieving an about 1 dB sensitivity improvement. We also assess the phase regeneration provided by the vector PSA when the signal phase is degraded.
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| 272. |
- Lorences Riesgo, Abel, 1987, et al.
(författare)
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Phase-Sensitive Amplification of 28 GBaud DP-QPSK Signal
- 2015
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Ingår i: 2015 Optical Fiber Communications Conference and Exhibition, OFC 2015, Los Angeles, United States, 22-26 March 2015. - Washington, D.C. : OSA. - 9781557529374 ; , s. 7122090-
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Konferensbidrag (refereegranskat)abstract
- We demonstrate, for the first time, amplification of a DP-QPSK signal using a vector phase-sensitive amplifier (PSA). The PSA-based receiver shows an about 0.7 dB sensitivity improvement compared to an EDFA-based receiver.
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| 273. |
- Lorences Riesgo, Abel, 1987, et al.
(författare)
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Polarization-Independent Phase-Sensitive Amplification
- 2016
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 34:13, s. 3171-3180
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Tidskriftsartikel (refereegranskat)abstract
- We thoroughly analyze the requirements on the signal and idler state of polarizations (SOPs) for achieving maximum amplification in phase-sensitive amplifiers (PSAs). These requirements are described using a Jones-space description as well as a Stokes-space description. Our analysis includes the cases of polarization-diverse and vector PSAs, and in each type of PSA, we also consider the signal-degenerate and the non-degenerate schemes. We observe that the relation between the signal and idler SOPs to achieve maximum phase-sensitive (PS) amplification can be described similarly in polarization-diverse and in vector PSAs. Moreover, both types of PSAs are polarization-dependent, which means that PSAs do require polarization-tracking schemes when being implemented in a realistic optical-transmission scenario. We therefore evaluate how polarization tracking of the signal and the idler SOPs can overcome the theoretical polarization dependence of both polarization-diverse and vector PSAs. We find that only one polarization tracker for either the signal or idler SOP is necessary for achieving polarization-independent PS amplification when considering the general case of dual-polarization (DP) modulated signals. This polarization tracker requires the control of three degrees of freedom which describe a general polarization rotation. For single-polarization (SP) modulated signals, the polarization tracker can rotate both the signal and the idler SOPs simultaneously which eliminates the need for splitting the signal and the idler before the PSA. Moreover, only two degrees of freedom for the polarization tracker are necessary in this case. When considering degenerate schemes, a polarization tracker with two degrees of freedom is sufficient to achieve maximum PS amplification of DP binary phase-shift keying (BPSK) signals in both vector and polarization diverse PSAs. For the case of SP-BPSK signals, a polarization-diverse PSA can perform polarization-independent amplification by controlling the relative phase between the pumps, whereas a polarization tracker with only one degree of freedom is necessary in the case of vector PSAs.
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| 274. |
- Lorences Riesgo, Abel, 1987, et al.
(författare)
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Quadrature decomposition of a 20 Gbaud 16-QAM signal into 2×4-PAM signals
- 2016
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Ingår i: 2016 European Conference in Optical Communication.
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Konferensbidrag (refereegranskat)abstract
- We propose a novel phase-sensitive processor capable of operating at low nonlinear phase shifts. With a nonlinear phase shift of 2 0.15 rad, quadrature decomposition is demonstrated with penalty of 0.5 dB at BER=10E-3.
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| 275. |
- Lorences Riesgo, Abel, 1987, et al.
(författare)
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Quadrature demultiplexing using a degenerate vector parametric amplifier
- 2014
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 22:24, s. 29424-29434
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Tidskriftsartikel (refereegranskat)abstract
- We report on quadrature demultiplexing of a quadrature phase-shift keying (QPSK) signal into two cross-polarized binary phase-shift keying (BPSK) signals with negligible penalty at bit-error rate (BER) equal to 10−9. The all-optical quadrature demultiplexing is achieved using a degenerate vector parametric amplifier operating in phase-insensitive mode. We also propose and demonstrate the use of a novel and simple phase-locked loop (PLL) scheme based on detecting the envelope of one of the signals after demultiplexing in order to achieve stable quadrature decomposition.
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| 276. |
- Lorences Riesgo, Abel, 1987, et al.
(författare)
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Self-homodyne 24×32-QAM superchannel receiver enabled by all-optical comb regeneration using Brillouin amplification
- 2016
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Ingår i: Optics Express. - : The Optical Society. - 1094-4087 .- 1094-4087. ; 24:26, s. 29714-29723
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate and characterize an all-optical self-homodyne (SH) frequency superchannel enabled by comb regeneration at the receiver. In order to generate the superchannel, we use a frequency comb with 26 carriers spaced by 25 GHz at the transmitter, from which 24 carriers are modulated with polarization-multiplexed 32 quadrature amplitude modulation (PM 32-QAM) data. To enable comb regeneration at the receiver side, the two central carriers remain unmodulated. High fidelity comb regeneration is achieved by filtering the two unmodulated carriers with an approximately 25 MHz wide optical filter based on Brillouin amplification before a parametric mixer. The carriers from the regenerated comb are then used as local oscillator for SH detection. We demonstrate that all 24 carriers can be detected with an optical signal-to-noise ratio (OSNR) penalty lower than 2.5 dB in a back-to-back scenario. We also demonstrate that the whole superchannel can be transmitted through 120 km of single-mode fiber (SMF) and be detected with bit-error rate (BER) below 0.015.
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| 277. |
- Lu, Guo-Wei, 1976, et al.
(författare)
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Format Conversion From 120-Gb/s RZ-D8PSK to 80-Gb/s RZ-DQPSK Through FWM-Based Optical Phase Erasure
- 2010
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 22:24, s. 1817-1819
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Tidskriftsartikel (refereegranskat)abstract
- An optical format conversion scheme from 120-Gb/s return-to-zero differential 8-ary phase-shift keying (RZ-D8PSK) to 80-Gb/s RZ differential quadrature phase-shift keying (RZ-DQPSK) is demonstrated by optically removing one tributary through optical phase erasure. It is achieved through four-wave mixing in a highly nonlinear fiber. An 8-dB sensitivity improvement is obtained for the converted DQPSK signal relative to that of the input D8PSK signal. This is potentially useful to enable the interconnection among neighboring networks where different formats are deployed.
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| 278. |
- Lu, Guo-Wei, 1976, et al.
(författare)
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Format Conversion of Optical Multilevel Signals Using FWM-Based Optical Phase Erasure
- 2011
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 29:16, s. 2460-2466
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Tidskriftsartikel (refereegranskat)abstract
- An optical format conversion scheme of multilevel phase-shift keying (M-ary PSK) signals using the four-wave mixing based optical phase erasure is discussed in this paper. The conversion from differential quadrature phase-shift keying (DQPSK) to differential phase shift keying at 10 and 160 Gbaud, and the conversion from differential eight-ary phase-shift keying to DQPSK at 40 Gbaud have been experimentally demonstrated. The proposed scheme could be used as a phase erasure, in which a redundant tributary of the M-ary PSK signal is removed, or as an "updater" where the unwanted phase pattern is replaced with the new pattern.
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| 279. |
- Lundberg, Lars, 1989, et al.
(författare)
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Frequency Comb-Based WDM Transmission Systems Enabling Joint Signal Processing
- 2018
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Ingår i: Applied Sciences (Switzerland). - : MDPI AG. - 2076-3417. ; 8:5
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Tidskriftsartikel (refereegranskat)abstract
- We review the use of optical frequency combs in wavelength-division multiplexed (WDM) fiber optic communication systems. In particular, we focus on the unique possibilities that are opened up by the stability of the comb-line spacing and the phase coherence between the lines. We give an overview of different techniques for the generation of optical frequency combs and review their use in WDM systems. We discuss the benefits of the stable line spacing of frequency combs for creating densely-packed optical superchannels with high spectral efficiency. Additionally, we discuss practical considerations when implementing frequency-comb-based transmitters. Furthermore, we describe several techniques for comb-based superchannel receivers that enables the phase coherence between the lines to be used to simplify or increase the performance of the digital carrier recovery. The first set of receiver techniques is based on comb-regeneration from optical pilot tones, enabling low-overhead self-homodyne detection. The second set of techniques takes advantage of the phase coherence by sharing phase information between the channels through joint digital signal processing (DSP) schemes. This enables a lower DSP complexity or a higher phase-noise tolerance.
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| 280. |
- Lundberg, Lars, 1989, et al.
(författare)
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Joint Carrier Recovery for DSP Complexity Reduction in Frequency Comb-Based Superchannel Transceivers
- 2017
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Ingår i: European Conference on Optical Communication, ECOC.
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Konferensbidrag (refereegranskat)abstract
- We experimentally demonstrate a master-slave carrier recovery scheme by joint processing of 10 GBd PM-64QAM phase-locked wavelength carriers. We measure negligible penalty up to a frequency spacing of 275 GHz, showing the potential for effective resource utilization among many wavelength channels.
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