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| 2. |
- Kakkar, Aditya, et al.
(author)
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Laser Frequency Noise in Coherent Optical Systems : Spectral Regimes and Impairments
- 2017
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In: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 7
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Journal article (peer-reviewed)abstract
- Coherent communication networks are based on the ability to use multiple dimensions of the lightwave together with electrical domain compensation of transmission impairments. Electrical-domain dispersion compensation (EDC) provides many advantages such as network flexibility and enhanced fiber nonlinearity tolerance, but makes the system more susceptible to laser frequency noise (FN), e.g. to the local oscillator FN in systems with post-reception EDC. Although this problem has been extensively studied, statistically, for links assuming lasers with white-FN, many questions remain unanswered. Particularly, the influence of a realistic non-white FN-spectrum due to e.g., the presence of 1/f-flicker and carrier induced noise remains elusive and a statistical analysis becomes insufficient. Here we provide an experimentally validated theory for coherent optical links with lasers having general non-white FN-spectrum and EDC. The fundamental reason of the increased susceptibility is shown to be FN-induced symbol displacement that causes timing jitter and/or inter/intra symbol interference. We establish that different regimes of the laser FN-spectrum cause a different set of impairments. The influence of the impairments due to some regimes can be reduced by optimizing the corresponding mitigation algorithms, while other regimes cause irretrievable impairments. Theoretical boundaries of these regimes and corresponding criteria applicable to system/laser design are provided.
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| 3. |
- Lu, Yang, et al.
(author)
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Matrix Receiving Scheme Supporting Arbitrary Multiple-Wavelength Reception for Optical Interconnects
- 2017
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In: European Conference on Optical Communication, ECOC. - : IEEE. - 9781538656242
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Conference paper (peer-reviewed)abstract
- An arbitrary multiple-wavelength reception scheme using only a few fixed-wavelength filters is proposed for optical interconnects. Filter matrices design based on error-control coding theory is devised. The feasibility of the proposed scheme is demonstrated in a four-wavelength reception experiment.
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| 4. |
- Marinins, Aleksandrs, et al.
(author)
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Cylindrical polymer optical waveguides with polarization independent performance
- 2017
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In: 2017 Conference on Lasers and Electro-Optics, CLEO 2017 - Proceedings. - : OSA Publishing. - 9781943580279 ; , s. 1-2
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Conference paper (peer-reviewed)abstract
- Heating of poly(methyl methacrylate) ridge optical waveguides slightly above glass transition temperature minimizes surface roughness and provides cylindrical shape. We experimentally demonstrate propagation loss decrease and polarization insensitivity as a result of waveguide thermal treatment.
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| 5. |
- Natalino Da Silva, Carlos, 1987, et al.
(author)
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One-shot learning for modulation format identification in evolving optical networks
- 2017
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In: Optics InfoBase Conference Papers. - : OSA - The Optical Society. - 9781557528209 ; Part F131-IPRSN 2019
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Conference paper (peer-reviewed)abstract
- We report on the first successful application of one-shot machine learning scheme that identifies new modulation formats based on a single constellation diagram without re-training. 100% accuracy is achieved when expanding from 2 to 5 supported modulation formats. © 2019 The Author(s).
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| 6. |
- Navarro, Jaime Rodrigo, et al.
(author)
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Blind phase search with angular quantization noise mitigation for efficient carrier phase recovery
- 2017
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In: Photonics. - : MDPI AG. - 2304-6732. ; 4:2
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Journal article (peer-reviewed)abstract
- The inherent discrete phase search nature of the conventional blind phase search (C-BPS) algorithm is found to introduce angular quantization noise in its phase noise estimator. The angular quantization noise found in the C-BPS is shown to limit its achievable performance and its potential low complexity implementation. A novel filtered BPS algorithm (F-BPS) is proposed and demonstrated to mitigate this quantization noise by performing a low pass filter operation on the C-BPS phase noise estimator. The improved performance of the proposed F-BPS algorithm makes it possible to significantly reduce the number of necessary test phases to achieve the C-BPS performance, thereby allowing for a drastic reduction of its practical implementation complexity. The proposed F-BPS scheme performance is evaluated on a 28-Gbaud 16QAM and 64QAM both in simulations and experimentally. Results confirm a substantial improvement of the performance along with a significant reduction of its potential implementation complexity compared to that of the C-BPS.
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| 7. |
- Ozolins, Oskars, et al.
(author)
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100 Gbaud 4PAM Link for High Speed Optical Interconnects
- 2017
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In: 43RD EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC 2017). - : IEEE.
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Conference paper (peer-reviewed)abstract
- We demonstrate 100 Gbaud 4PAM transmission over 400 meters SMF with monolithically integrated 1550 nm DFB-TWEAM having 100 GHz 3-dB bandwidth with 2 dB ripple. We evaluate its capabilities to enable two lanes 400 GbE client-side links for optical interconnects. © 2017 IEEE.
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| 8. |
- Ozolins, Oskars, et al.
(author)
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100 GHz Externally Modulated Laser for Optical Interconnects
- 2017
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In: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 35:6, s. 1174-1179
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Journal article (peer-reviewed)abstract
- We report on a 116 Gb/s on-off keying (OOK), four pulse amplitude modulation (PAM) and 105-Gb/s 8-PAM optical transmitter using an InP-based integrated and packaged externally modulated laser for high-speed optical interconnects with up to 30 dB static extinction ratio and over 100-GHz 3-dB bandwidth with 2 dB ripple. In addition, we study the tradeoff between power penalty and equalizer length to foresee transmission distances with standard single mode fiber.
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| 9. |
- Pang, Xiaodan, Dr., et al.
(author)
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4 Gbps PAM-4 and DMT Free Space Transmission using a 4.65-pm Quantum Cascaded Laser at Room Temperature
- 2017
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In: European Conference on Optical Communication, ECOC. - : Institute of Electrical and Electronics Engineers Inc.. - 9781538656242 ; , s. 1-3
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Conference paper (peer-reviewed)abstract
- We experimentally demonstrate 4Gbps PAM-4 and DMT transmissions using a quantum cascaded laser (QCL) emitting at mid-wavelength infrared of 4.65μm and a commercial infrared photovoltaic detector. The QCL is directly modulated and operated at room temperature with Peltier Cooling.
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| 10. |
- Pang, Xiaodan, et al.
(author)
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Experimental Study of 1.55-μ m EML-Based Optical IM/DD PAM-4/8 Short Reach Systems
- 2017
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In: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers Inc.. - 1041-1135 .- 1941-0174. ; 29:6, s. 523-526
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Journal article (peer-reviewed)abstract
- We experimentally evaluate high-speed intensity modulation/direct detection (IM/DD) transmissions with a 1.55-μ text broadband electro-Absorption modulated laser and pulse amplitude modulations (PAM). We demonstrate 80 Gb/s/ λ PAM-4 and 96 Gb/s/ λ PAM-8 transmissions with low-complexity digital equalizers at the receiver. Performance comparison with different types of equalizers are performed, including linear symbol-spaced feed-forward equalizer (FFE), fractional (half-symbol) spaced FFE and decision feedback equalizer (DFE), with different tap number. It is found that for both cases, a 6-Tap symbol-spaced FFE is sufficient to achieve a stable performance with bit-error-rate below the 7% overhead hard decision forward error correction (7%-OH HD-FEC) threshold over a 4 km standard single mode fiber link. Practical considerations including comparison between adaptive and static equalizer implementation and tolerable fiber chromatic dispersion are discussed.
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