| 1. |
- Ellis, A. D., et al.
(author)
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Future Directions to Realize Ultra-High Bit-Rate Transmission Systems
- 2010
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In: Proceedings of OptoElectronics and Communications Conference, OECC 2010, Sapporo, Japan, 5-9 July 2010, invited paper..
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Conference paper (other academic/artistic)abstract
- In this paper we examine two potential future directions for the realization of ultra-high bit rate transmission systems.
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| 2. |
- Gallo, Katia, et al.
(author)
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Processing ultrafast optical signals in broadband telecom systems by means of cascaded quadratic nonlinearities
- 2006
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In: ICTON 2006. ; , s. 222-226
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Conference paper (peer-reviewed)abstract
- Quadratic optical nonlinearities offer several attractive features for the implementation of ultra-fast, low-noise and transparent telecom devices. Technological progress has dramatically increased their efficiency, driving a steady move towards practical applications. In this talk we shall discuss the use of cascaded quadratic interactions in LiNbO3 integrated devices for pulse diagnostics, format conversion and signal regeneration in ultra-fast multi-wavelength telecom systems.
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| 3. |
- Kakande, Joseph, et al.
(author)
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Detailed characterization of a
fiber-optic parametric amplifier in phase-sensitive and phase-insensitive operation
- 2010
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In: Optics Express. - 1094-4087 .- 1094-4087. ; 18:5, s. 4130-4137
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Journal article (peer-reviewed)abstract
- We experimentally demonstrate a single-pumped, non-degenerate phase-sensitive parametric amplifier with a precise control of phase and amplitude of the in-going waves and investigate in detail its gain, attenuation and saturation properties in comparison with operation in phase insensitive amplifier (PIA) mode. We experimentally observe the variation of the gain and attenuation as a function of the relative phase, pump power and the signal-idler power ratio. The phase sensitive gain spectrum is studied over a 24 nm symmetrical bandwidth and we achieve a maximum phase sensitive amplification (PSA) gain of 33 dB. A departure from the theoretical maximum attenuation as the gain increases is observed and explained.
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| 4. |
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| 5. |
- Lee, Kwang Jo, et al.
(author)
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OTDM to WDM format conversion based on quadratic cascading in a periodically poled lithium niobate waveguide
- 2010
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In: Optics Express. - 1094-4087. ; 18:10, s. 10282-10288
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Journal article (peer-reviewed)abstract
- We propose and demonstrate error-free conversion of a 40 Gbit/s optical time division multiplexed signal to 4 x 10 Gbit/s wavelength division multiplexed channels based on cascaded second harmonic and difference frequency generation in a periodically poled lithium niobate waveguide. The technique relies on the generation of spectrally (and temporally) flat linearly chirped pulses which are then optically switched with short data pulses in the nonlinear waveguide. Error-free operation was obtained for all channels with a power penalty below 2dB.
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| 6. |
- Lee, Kwang Jo, et al.
(author)
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Phase sensitive amplification based on quadratic cascading in a periodically poled lithium niobate waveguide
- 2009
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In: Optics Express. - 1094-4087. ; 17:22, s. 20393-20400
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Journal article (peer-reviewed)abstract
- We propose and demonstrate phase-sensitive amplification based on cascaded second harmonic generation and difference frequency generation within a periodically poled lithium niobate waveguide. Excellent agreement between our numerical simulations and proof-of-principle experiments using a 3-cm waveguide device operating at wavelengths around 1550 nm is obtained. Our experiments confirm the validity and practicality of the approach and illustrate the broad gain bandwidths achievable. Additional simulation results show that the maximum gain/attenuation factor increases quadratically with input pump power, reaching a value of +/- 19.0dB at input pump powers of 33 dBm for a 3 cm-long waveguide. Increased gains/reduced powers for a fixed gain could be achieved using longer crystals.
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| 7. |
- Liu, Sheng, et al.
(author)
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Phase-regenerative wavelength conversion in periodically poled lithium niobate waveguides
- 2011
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In: Optics Express. - 1094-4087. ; 19:12, s. 11705-11715
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Journal article (peer-reviewed)abstract
- We propose and experimentally demonstrate phase-regenerative wavelength conversion in periodically poled lithium niobate waveguides, using either: a single-stage implementation based on a simultaneous combination of two cascaded second-order nonlinear effects in a single periodically poled lithium niobate waveguide, or a two-stage implementation where two separate devices are used in sequence to give rise to the same nonlinear effects. The phase regeneration properties of the proposed wavelength conversion schemes are also investigated.
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| 8. |
- Liu, Sheng, et al.
(author)
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Retiming of Short Pulses Using Quadratic Cascading in a Periodically Poled Lithium Niobate Waveguide
- 2011
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In: IEEE Photonics Technology Letters. - : IEEE. - 1041-1135 .- 1941-0174. ; 23:2, s. 94-96
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Journal article (peer-reviewed)abstract
- We demonstrate an all-optical technique for the mitigation of timing jitter in short pulse transmission systems. The technique relies on pulse preshaping followed by optical switching in a periodically poled lithium niobate waveguide via cascaded second harmonic and difference frequency generation. The original data pulses are shaped into flat-top pulses to avoid conversion of their timing jitter into pulse amplitude noise at the output of the waveguide. Pulse retiming is confirmed by temporal measurements, while bit-error-rate measurements confirm good noise performance for the system.
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| 9. |
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| 10. |
- Minzioni, Paolo, et al.
(author)
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Roadmap on all-optical processing
- 2019
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In: Journal of Optics. - : IOP Publishing. - 2040-8978 .- 2040-8986. ; 21:6
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Journal article (peer-reviewed)abstract
- The ability to process optical signals without passing into the electrical domain has always attracted the attention of the research community. Processing photons by photons unfolds new scenarios, in principle allowing for unseen signal processing and computing capabilities. Optical computation can be seen as a large scientific field in which researchers operate, trying to find solutions to their specific needs by different approaches; although the challenges can be substantially different, they are typically addressed using knowledge and technological platforms that are shared across the whole field. This significant know-how can also benefit other scientific communities, providing lateral solutions to their problems, as well as leading to novel applications. The aim of this Roadmap is to provide a broad view of the state-of-the-art in this lively scientific research field and to discuss the advances required to tackle emerging challenges, thanks to contributions authored by experts affiliated to both academic institutions and high-tech industries. The Roadmap is organized so as to put side by side contributions on different aspects of optical processing, aiming to enhance the cross-contamination of ideas between scientists working in three different fields of photonics: optical gates and logical units, high bit-rate signal processing and optical quantum computing. The ultimate intent of this paper is to provide guidance for young scientists as well as providing research-funding institutions and stake holders with a comprehensive overview of perspectives and opportunities offered by this research field.
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| 11. |
- Parmigiani, Francesca, et al.
(author)
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All-Optical Phase Regeneration of 40Gbit/s DPSK Signals in a Black‐Box Phase Sensitive Amplifier
- 2010
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In: 2010 Conference on Optical Fiber Communication, Collocated National Fiber Optic Engineers Conference, OFC/NFOEC 2010; San Diego, CA; United States; 21 March 2010 through 25 March 2010. - 9781557528841 ; , s. PDPC3-
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Conference paper (peer-reviewed)abstract
- We present a black‐box four wave mixingbased bit‐rate‐flexible phase sensitive amplifier and use it in the first demonstration of 40 Gbit/s DPSK phaseregeneration.
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| 12. |
- Parmigiani, Francesca, et al.
(author)
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Phase sensitive amplification based on cascaded SHG / DFG process in a periodically poled lithium niobate waveguide
- 2009
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Conference paper (peer-reviewed)abstract
- Phase-sensitive amplifiers (PSAs) have long been known to offer the possibility of amplification with a noise figure below the 3 dB quantum limit of phase insensitive amplifiers (PIA). Other advantages of the PSAs are the potential for optical signal processing, including all optical phase regeneration of phase encoded signals, dispersion compensation and coherent wavelength exchange. PSAs are usually demonstrated using highly nonlinear fibres as the nonlinear element. However, the use of cascaded sum- and difference-frequency generation (cSFG/DFG) of second-order nonlinearities in periodically poled lithium niobate (PPLN) waveguides offers a number of attractive features relative to corresponding fibre based PSA implementations including the prospect of compact devices, large operational bandwidths and importantly a far greater immunity to the effects of Stimulated Brillouin Scattering (SBS) of the pump beams which imposes performance limitations and adds complexity to silica fibre based PSA devices. Herein, we propose and demonstrate both theoretically and experimentally a new scheme for frequency non-degenerate PSA based on the cSHG/DFG process in a single PPLN waveguide
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| 13. |
- Petropoulos, Periklis, et al.
(author)
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Processing of telecommunication signals using periodically poled lithium niobate waveguides
- 2010
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In: 2010 12th International Conference on Transparent Optical Networks (ICTON).
-
Conference paper (peer-reviewed)abstract
- This talk reports on processing of high-speed telecommunication signals based on cascaded quadratic nonlinearities in periodically poled lithium niobate (PPLN) waveguides. A strong pump positioned within the acceptance bandwidth of the PPLN device can interact via a cascaded nonlinear process with a second signal, thereby facilitating a switch with a broad optical bandwidth and yielding an output located within the same wavelength band as the inputs. The combination of the PPLN switch with custom-designed optical filtering for pre-conditioning of the signals gives rise to a versatile pulse processing system exhibiting important advantages in terms of compactness and environmental stability. As an example, Fig.1 describes schematically how an optical time-division multiplexed (OTDM) signal can be converted through cascaded second-harmonic generation and difference-frequency generation to a wavelength-division multiplexed (WDM) signal. The experiments that have led to this demonstration will be described in the talk. Another exciting possibility offered by the action of periodically poled waveguides relates to the coherent manipulation of the optical phase of signals. Recent demonstrations relating to phase-sensitive amplification, as well as novel applications effecting to the elimination of chirp from optical signals will also be outlined in the talk.
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| 14. |
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| 15. |
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| 16. |
- Slavík, Radan, et al.
(author)
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All-optical phase and amplitude regenerator for next-generation telecommunications systems
- 2010
-
In: Nature Photonics. - 1749-4885 .- 1749-4893. ; 4:10, s. 690-695
-
Journal article (peer-reviewed)abstract
- Fibre-optic communications systems have traditionally carried data using binary (on-off) encoding of the light amplitude. However, next-generation systems will use both the amplitude and phase of the optical carrier to achieve higher spectral efficiencies and thus higher overall data capacities. Although this approach requires highly complex transmitters and receivers, the increased capacity and many further practical benefits that accrue from a full knowledge of the amplitude and phase of the optical field more than outweigh this additional hardware complexity and can greatly simplify optical network design. However, use of the complex optical field gives rise to a new dominant limitation to system performance—nonlinear phase noise. Developing a device to remove this noise is therefore of great technical importance. Here, we report the development of the first practical (‘black-box’) all-optical regenerator capableof removing both phase and amplitude noise from binary phase-encoded optical communications signals.
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| 17. |
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| 18. |
- Tyekucheva, Svitlana, et al.
(author)
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Stromal and epithelial transcriptional map of initiation progression and metastatic potential of human prostate cancer
- 2017
-
In: Nature Communications. - London, United Kingdom : Nature Publishing Group. - 2041-1723. ; 8:1
-
Journal article (peer-reviewed)abstract
- While progression from normal prostatic epithelium to invasive cancer is driven by molecular alterations, tumor cells and cells in the cancer microenvironment are co-dependent and co-evolve. Few human studies to date have focused on stroma. Here, we performed gene expression profiling of laser capture microdissected normal non-neoplastic prostate epithelial tissue and compared it to non-transformed and neoplastic low-grade and high-grade prostate epithelial tissue from radical prostatectomies, each with its immediately surrounding stroma. Whereas benign epithelium in prostates with and without tumor were similar in gene expression space, stroma away from tumor was significantly different from that in prostates without cancer. A stromal gene signature reflecting bone remodeling and immune-related pathways was upregulated in high compared to low-Gleason grade cases. In validation data, the signature discriminated cases that developed metastasis from those that did not. These data suggest that the microenvironment may influence prostate cancer initiation, maintenance, and metastatic progression.Stromal cells contribute to tumor development but the mechanisms regulating this process are still unclear. Here the authors analyze gene expression profiles in the prostate and show that stromal gene signature changes ahead of the epithelial gene signature as prostate cancer initiates and progresses.
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