| 1. |
- Bakhshi, Bamdad, 1970, et al.
(author)
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Experimental observation of soliton robustness to polarisation dispersion pulse broadening
- 1999
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In: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 35:1, s. 65-66
-
Journal article (peer-reviewed)abstract
- Soliton robustness to polarisation dispersion pulse broadening in a 400km installed optical fibre is experimentally demonstrated. With 10ps input pulses and a differential group delay of 7.6ps, the soliton pulsewidth at the receiver is maintained within 10-11ps when the input polarisation is changed, while the corresponding range for dispersion-compensated linear pulses is 10.5-15.5ps.
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| 2. |
- Bakhshi, Bamdad, 1970, et al.
(author)
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Measurement of the differential group delay in installed optical fibers using polarization multiplexed solitons
- 1999
-
In: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 11:5, s. 593-595
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Journal article (peer-reviewed)abstract
- We experimentally demonstrate a new technique for measurement of the differential group delay (DGD) in optical fibers using polarization-division multiplexed (PDM) solitons: the change in the separation of orthogonally polarized solitons propagating along different principal axes in a fiber equals the DGD at the signal wavelength. Based on this principle, we use PDM solitons to measure the accumulated DGD at different distances along a 400-km installed fiber. The measured DGD exhibits the expected square-root-of-length dependence, corresponding to a polarization-mode dispersion of 0.26 ps/km1/2. The results are in excellent agreement with those obtained by a commercial instrument utilizing Jones matrix eigenanalysis.
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| 3. |
- Brentel, Jonas, et al.
(author)
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Single-wavelength 40 Gb/s soliton field transmission experiments over 400 km fibre without in-line control
- 1999
-
In: OFC/IOOC 1999 - Optical Fiber Communication Conference and the International Conference on Integrated Optics and Optical Fiber Communication. - 155752582X ; 3, s. 121-124
-
Conference paper (peer-reviewed)abstract
- We report single-wavelength 40-Gbit/s soliton transmission over 400-km installed fiber lines in Sweden. Both polarization-division multiplexed and parallel solitons were transmitted. The system performance is dominated by the polarization-mode dispersion.
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| 4. |
- Chen, Jingjing, 1982, et al.
(author)
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Demonstration of analog millimeter-wave fronthaul for 64-QAM LTE transmission
- 2015
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In: IEEE Vehicular Technology Conference. - 1550-2252.
-
Conference paper (peer-reviewed)abstract
- Centralized baseband architecture is believed to be cost efficient and to offer high network performance. The fronthaul network, connecting the centralized baseband to distributed remote radios, requires high capacity and low latency transport links, due to the stringent specifications of the data interface, known as common public radio interface (CPRI). Today, fronthaul links are mostly based on digital CPRI over fibers, although it is possible to realize CPRI over wireless technology with the drawback of poor bandwidth efficiency. In this paper, we propose an analog wireless fronthaul concept to enable bandwidth efficient and scalable fronthaul networks. The basic idea is to transport narrow band analog radio signals over millimeter-wave bands instead of multi-gigabit digital signals. The phase and frequency impairments introduced by high frequency carriers are effectively reduced using an analog pilot-based mitigation technique. As a proof-of-concept demonstration, an analog fronthaul link is implemented, and the link performance is verified for 20 MHz 64-QAM LTE transmission over 70/80 GHz (E-band). The measured error vector magnitude (EVM) is about 3% with 10% pilot bandwidth overhead.
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| 5. |
- Chen, Jingjing, 1982, et al.
(author)
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Experimental demonstration of RF-pilot-based phase noise mitigation for millimeter-wave systems
- 2014
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In: IEEE Vehicular Technology Conference. - 1550-2252. - 9781479944491 ; , s. Art. no. 6965978-
-
Conference paper (peer-reviewed)abstract
- Millimeter-wave bands are gaining popularity for high data rate wireless communication systems due to the wide available bandwidth. However, oscillator phase noise also increases as the carrier frequency increases. Methods of phase noise mitigation are therefore crucial for future millimeter-wave systems. In this work, we propose to adopt analog phase noise mitigation using an RF-pilot tone, which reduces both phase and frequency impairments of an arbitrary millimeter-wave signal at the expense of reduced spectral efficiency. The method is verified experimentally at carrier frequency of 28 GHz and E-band 73 GHz showing a 20 dB noise reduction up to 100 kHz offset. Since the method relaxes phase noise requirement it is attractive for phase noise sensitive technologies at high carrier frequency, such as OFDM used in LTE. As indicated by the simulation results, the reduced phase noise enables a LTE signal on a millimeter-wave carrier with marginal performance impact.
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| 6. |
- Ge, Yu, 1995, et al.
(author)
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Experimental Validation of Single BS 5G mmWave Positioning and Mapping for Intelligent Transport
- 2024
-
In: IEEE Transactions on Vehicular Technology. - 0018-9545 .- 1939-9359. ; In Press
-
Journal article (peer-reviewed)abstract
- Positioning with 5G signals generally requires connection to several base stations (BSs), which makes positioning more demanding in terms of infrastructure than communications. To address this issue, there have been several theoretical studies on single BS positioning, leveraging high-resolution angle and delay estimation and multipath exploitation possibilities at mmWave frequencies. This paper presents the first realistic experimental validation of such studies, involving a commercial 5G mmWave BS with a customized beam sweep procedure and a user equipment (UE) development kit mounted on a test vehicle. We present the relevant signal models, and signal processing methods, and validate these based on data collected in an outdoor science park environment. Our results indicate that positioning is possible, but the performance is limited by the knowledge of the position and orientation of the infrastructure and the multipath visibility and diversity
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| 7. |
- Gevorgian, Spartak, 1948, et al.
(author)
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Tunable delay line arrangement
- 2013
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Other publication (other academic/artistic)abstract
- A tunable chirped delay line arrangement (0) configured to operatively propagate a signal and includes a at least one chirped delay line (1) arranged along a reference direction (z) on a dielectric layer (2) arranged on a ground plane (3). The chirped delay line (1) is configured with a smoothly varying width along the reference direction (z), and the arrangement (0) further comprising at least one electronically tunable impedance (5) interconnecting the at least one delay line (1) and the ground plane (3) at at least one location along the reference direction (z) such that the at least one delay line (1) is loaded by the tunable impedance
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| 8. |
- Gustavsson, Johan, 1974, et al.
(author)
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High-speed 850-nm VCSELs for 40 Gb/s transmission
- 2010
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Conference paper (other academic/artistic)abstract
- We have explored the possibility to extend the data transmission rate for standard 850-nm GaAs-based VCSELs beyond the 10 Gbit/s limit of today's commercially available directly-modulated devices. By sophisticated tailoring of the design for high-speed performance we demonstrate that 10 Gb/s is far from the upper limit. For example, the thermal conductivity of the bottom mirror is improved by the use of binary compounds, and the electrical parasitics are kept at a minimum by incorporating a large diameter double layered oxide aperture in the design. We also show that the intrinsic high speed performance is significantly improved by replacing the traditional GaAs QWs with strained InGaAs QWs in the active region. The best overall performance is achieved for a device with a 9 μm diameter oxide aperture, having in a threshold current of 0.6 mA, a maximum output power of 9 mW, a thermal resistance of 1.9 °C/mW, and a differential resistance of 80 Ω. The measured 3dB bandwidth exceeds 20 GHz, and we experimentally demonstrate that the device is capable of error-free transmission (BER
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| 9. |
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| 10. |
- Hedekvist, Per Olof E, 1967, et al.
(author)
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Microwave Harmonic Frequency Generation utilizing the properities of an Optical Phase Modulator
- 2004
-
In: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 22:3, s. 882-886
-
Journal article (peer-reviewed)abstract
- New techniques to generate a harmonic microwave frequency modulated on an optical carrier are presented. All these techniques utilize the polarization-dependent properties of a LiNbO3-phase modulator and manage to achieve 40-GHz modulation using only 10-GHz electronics. The signal quality of the generated frequency is mainly determined by the 10-GHz signal generator, and the suppression of undesired lower order harmonic frequencies exceeds 30 dB.
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| 11. |
- Karlsson, Magnus, 1967, et al.
(author)
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PMD Compensation Using 2R and 3R Regenerators
- 2004
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In: Proceedings of European Conference on Optical Communication, ECOC 2004´, Stockholm, Sweden,September 5-9, 2004. ; , s. Paper We1.4.2-
-
Conference paper (peer-reviewed)
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| 12. |
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| 13. |
- Kolltveit, Erling, et al.
(author)
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Single-wavelength 40 Gbit/s soliton field transmission experiment over 400 km of installed fibre
- 1999
-
In: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 35:1, s. 75-76
-
Journal article (peer-reviewed)abstract
- 40Gbit/s soliton transmission over 400km (57km amplifier spacing) of installed lines without in-line control has been achieved. The maximum transmission penalties for parallel polarised and polarisation division multiplexed soliton transmission were ∼4 and 1dB, respectively. The transmission distance is the longest ever reported for a field trial with a single wavelength bit rate > 20Gbit/s for any optical transmission format. The polarisation mode dispersion was numerically found to completely dominate the system performance.
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| 14. |
- Li, Jie, 1967, et al.
(author)
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0.5 Tbit/s eye-diagram measurement by optical sampling using XPM-induced wavelength shifting in highly nonlinear fiber
- 2003
-
In: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 16:2, s. 566-568
-
Journal article (peer-reviewed)abstract
- In this letter, we report on a novel all-optical sampling scheme using cross-phase modulation-induced wavelength shifting and optical filtering. Up to 500-Gb/s optical signal eye-diagram measurements have been demonstrated for the first time with a temporal resolution of 0.7 ps. Signal operational wavelength range covering basically the whole erbium-doped fiber amplifier gain range (1535-1569 nm) with temporal resolutions equal to or less than 1 ps was also demonstrated in the experiment. These results show that the sampling system is suitable for directly monitoring and evaluating ultrahigh bit-rate optical time-division multiplexed data at or above 160 Gb/s.
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| 15. |
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| 16. |
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| 17. |
- Li, Jie, 1966, et al.
(author)
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OTDM Add & Drop Multiplexer Based on XPM-Induced Wavelength Shifting in Highly Nonlinear Fiber
- 2005
-
In: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 23:9, s. 2654-2661
-
Journal article (peer-reviewed)abstract
- In this paper, we study experimentally and numerically simultaneous time-domain add-drop multiplexing for high-speed optical time-division multiplexing (OTDM) networks based on cross-phase-modulation (XPM)-induced wavelength shifting in a 50-m highly nonlinear fiber. This scheme needs only a single-channel clock rate and does not alter the input signal wavelength. Simultaneous add and drop operations at 80 Gb/s have been demonstrated experimentally with less than 1-dB power penalty for the dropped channel and no distinct bit-error-rate (BER) degradation for the added channel. Numerical simulations show that the experimental results are only limited by the available signal pulsewidth, and simultaneous add-drop multiplexing at 160-Gb/s or higher bit rates is possible with this scheme by employing control and signal pulses with proper pulsewidths. © 2005 IEEE.
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| 18. |
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| 19. |
- Olsson, Bengt-Erik, 1968
(author)
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All-Optical Switching with the Nonlinear Optical Loop Mirror
- 1998
-
Doctoral thesis (other academic/artistic)abstract
- This thesis deals with the theory and applications of the nonlinear optical loop mirror (NOLM). Novel methods to restore and filter optical data as well as generate high peak power optical pulses using the NOLM are demonstrated. Further more, new approaches for polarization indep endent demultiplexing and a fully polarization independent all-optical AND-gate are proposed and experimentally demonstrated. The NOLM has been widely employed as an ultrafast demultiplexing device with the potential of demultiplexing data at speeds beyond 1 Tbit/s. The nonlinear characteristics of the NOLM can also be utilized for other all-optical applications such as filtering and logic operations. The nonlinear transmission characteristic is used to substantially improve the extinction ratio of an optical data sequence and remove low intensity noise over a wide spectral range. The proposed filtering technique is also successfully employed in a chain of optical amplifiers to generate pulses with very high peak power. Several new schemes for performing polarization independent all optical switching using standard dispersion shifted fibers are also proposed and demonstrated. One scheme utilizes a birefringent element in a control power balanced propagation diversity NOLM. This control power balanced NOLM is shown not to suffer from control power induced crosstalk as the conventional NOLM does. Another scheme employs a dispersion shifted fiber with random birefringence and has the advantage of being polarization independent of both data and control signal, thus constituting a polarization independent AND-gate. Finally a scheme utilizing the optical Kerr effect in a polarization diversity loop is demonstrated. This scheme is not an interferometer which results in better stability than other NOLMs. In addition, a solution to make the NOLM insensitive to acoustical disturbances by rewinding the loop fiber is demonstrated.
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| 20. |
- Olsson, Bengt-Erik, 1968, et al.
(author)
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OTDR technique for characterization of fiber optic parametric amplifiers
- 2006
-
In: OFC/NFOEC 2006. 2006 Optical Fiber Communication Conference and National Fiber Optic Engineers Conference. ; , s. OWT3-
-
Conference paper (peer-reviewed)abstract
- A novel technique for characterization of power evolution in fiber optic parametric amplifiers based on optical time domain reflectometry is presented. The technique is suitable for analyzing the exponential gain along the amplifying fiber
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| 21. |
- Olsson, Bengt-Erik, 1968, et al.
(author)
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Polarization mode dispersion measurement using a Sagnac interferometer and a comparison with the fixed analyzer method
- 1998
-
In: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 10:7, s. 997-999
-
Journal article (peer-reviewed)abstract
- Polarization mode dispersion measurement using a Sagnac interferometer is compared with the well-known fixed analyzer technique both theoretically and experimentally. It is shown that in the case of weak mode coupling in the fiber the Sagnac interferometer method is equivalent to the fixed analyzer method but gives better readability of the measured optical spectrum. For strong mode coupling, we develop a theory that relates the differential group delay to the number of mean-level crossings in the measured spectrum.
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| 22. |
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| 23. |
- Olsson, Daniel S, 1983, et al.
(author)
-
Tumour recurrence and enlargement in patients with craniopharyngioma with and without GH replacement therapy during more than 10 years of follow-up.
- 2012
-
In: European journal of endocrinology. - 1479-683X. ; 166:6, s. 1061-8
-
Journal article (peer-reviewed)abstract
- Most patients who have been treated for craniopharyngioma (CP) are GH deficient (GHD). GH replacement therapy (GHRT) may stimulate tumour regrowth; and one of the concerns with long-term GHRT is the risk of tumour progression. Therefore, the objective was to study tumour progression in CP patients on long-term GHRT.Case-control study.The criteria for inclusion of cases were: i) GHD caused by CP; ii) GHRT >3 years; and iii) regular imaging. This resulted in 56 patients (mean age at diagnosis 25±16 years) with a mean duration of GHRT of 13.6±5.0 years. As controls, 70 CP patients who had not received GHRT were sampled with regard to follow-up, gender, age at diagnosis and initial radiation therapy (RT).The 10-year tumour progression-free survival rate (PFSR) for the entire population was 72%. There was an association (hazard ratio, P value) between PFSR and initial RT (0.13, 0.001) and residual tumour (3.2, 0.001). The 10-year PFSR was 88% for the GHRT group and 57% for the control group. Substitution with GHRT resulted in the following associations to PFSR: GHRT (0.57, 0.17), initial RT (0.16, <0.001), residual tumour (2.6, <0.01) and gender (0.57, 0.10). Adjusted for these factors, the 10-year PFSR was 85% for the GHRT group and 65% for the control group.In patients with CP, the most important prognostic factors for the PFSR were initial RT and residual tumour after initial treatment. Long-term GHRT did not affect the PFSR in patients with CP.
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| 24. |
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| 25. |
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| 26. |
- Rundstedt, Karl, 1990, et al.
(author)
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On Field Measurements and Modelling of 2x2 Microwave LOS-MIMO Systems
- 2015
-
In: Proceedings - IEEE Global Communications Conference, GLOBECOM. - 2334-0983 .- 2576-6813. - 9781479959525
-
Conference paper (peer-reviewed)abstract
- In this paper, we present channel measurementsand preliminary analyses from three 2x2 microwave Lineof-Sight Multi-Input Multi-Output (LOS-MIMO) outdoor test links, operating on 8 GHz and 32 GHz. The main focus of the measurement campaign is to study channel conditions and the effects of rain and clear-air fading. First, we address the diverse performance measures used in the trials. In particular we introduce the MIMO phase difference as an additional channel metric to the received power. The MIMO phase difference is mainly determined by antenna positions, ground effects and atmospheric variations. The relation between antenna positions and channel conditions was addressed in a number of earlier works, while the atmospheric impact and the resulting link availability are rarely studied. Second, we present the preliminary results from the long-term measurement campaign. The longterm statistics of channel condition from the three links show stable performance. Analysis reveals that fluctuation of the phase difference and the channel condition number is likely due to abnormal atmospheric propagation which can be modelled using a two-ray reflection model. Meanwhile, rain attenuation is strongly correlated between MIMO sub-channels and its contribution to the long-term statistics of power loss is very close to the Single-Input Single-Output (SISO) case.
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| 27. |
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| 28. |
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| 29. |
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| 30. |
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| 31. |
- Sköld, Mats, 1977, et al.
(author)
-
Polarization-based Monitoring in WDM Systems
- 2007
-
In: Proceedings of Optoelectronics and Communications Conference. - 9784885522215 ; , s. 346-347
-
Conference paper (other academic/artistic)
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| 32. |
- Sunnerud, Henrik, 1971, et al.
(author)
-
Polarization-mode dispersion measurements along installed optical fibers using gated backscattered light and a polarimeter
- 2000
-
In: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 18:7, s. 897-904
-
Journal article (peer-reviewed)abstract
- We describe two new techniques that utilize a polarimeter for studying the state of polarization of gated Rayleigh-backscattered or Fresnel-backreflected light along optical fibers in real time on the Poincare sphere. The first method, using Rayleigh-backscattered light, is here applied to measure the accumulation of polarization-mode dispersion (PMD) along an 11.5 km section of installed fiber link. With a simplified configuration, the second technique is developed and applied for measuring the PMD of individual fiber subsections in a 37 km long link. This is achieved by using the Fresnel-reflections which arise from the fiber connectors that join the link.
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| 33. |
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| 34. |
- Toft, Fredrik, 1986, et al.
(author)
-
Feasibility study of FPGA-based equalizer for 112-Gbit/s optical fiber receivers
- 2012
-
In: ISCAS 2012 - 2012 IEEE International Symposium on Circuits and Systems. - 9781467302180 ; , s. 3234-3237
-
Conference paper (peer-reviewed)abstract
- With ever increasing demands on spectral efficiency, complex modulation schemes are being introduced in fiber communication. However, these schemes are challenging to implement as they drastically increase the computational burden at the fiber receiver's end. We perform a feasibility study of implementing a 16-QAM112-Gbit/s decision directed equalizer on a state-of-the-art FPGA platform. An FPGA offers the reconfigurability needed to allow for modulation scheme updates, however, its clock rate is limited. For this purpose, we introduce a new phase correction technique to significantly relax the delay requirement on the critical phase-recovery feedback loop.
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| 35. |
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| 36. |
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| 37. |
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| 38. |
- Torounidis, Thomas, 1976, et al.
(author)
-
Gain and bandwidth characterization in fiber optical parametric amplifiers
- 2006
-
In: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 18:24, s. 2578-2580
-
Journal article (peer-reviewed)abstract
- The fiber optical parametric amplifier (FOPA) is characterized using a optical time-domain reflectometer-based technique. The measurement technique visualizes how the parametric gain and bandwidth evolves as a function of length. Both gain and bandwidth are measured and compared to theory and a good agreement is found between them, making this technique useful for characterization of FOPAs. The impact of zero dispersion wavelength variations in the fiber and polarization dependence of the measurement technique are also discussed.
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| 39. |
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| 40. |
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| 41. |
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| 42. |
- Wiberg, Andreas, 1978, et al.
(author)
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Dispersion-Tolerant Millimeter-Wave Photonic Link Using Polarization-Dependent Modulation
- 2007
-
In: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 25:10, s. 2984-2991
-
Journal article (peer-reviewed)abstract
- A novel technique to modulate one carrier in a dual–carrier millimeter-wave (mm-wave) photonic system is presented and experimentally evaluated. The technique utilizes the polarization dependence of an optical phase modulator and the properties of optical heterodyning and is demonstrated for both amplitudeand phase-modulated mm-wave signal outputs. Experimental verification of the technique is presented with transmission of up to 2.5-Gb/s nonreturn-to-zero data, multilevel quadratic-amplitude modulation, and IEEE 802.11a WLAN data signals on a 40-GHzcarrier over optical fiber and wireless transmission. The tolerance for fiber dispersion is investigated, and penalty-free transmission over 44 km is verified. The linearity of the system is evaluated by measuring the spurious-free dynamic range.
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| 43. |
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| 44. |
- Wiberg, Andreas, 1978, et al.
(author)
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Single Cycle Subcarrier Modulation
- 2009
-
In: 2009 Conference on Optical Fiber Communication, OFC 2009; San Diego, CA; United States; 22 March 2009 through 26 March 2009. - Washington, D.C. : OSA. - 9781557528650 ; , s. OTuE1-
-
Conference paper (peer-reviewed)abstract
- We report experimental demonstration of a concept of subcarrier modulation with the symbol rate and carrier frequency being identical, and thereby synchronous. The concept is demonstrated with 2.5 Gsymbols/s signals generated with binary digital electronics.
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