| 1. |
- Eriksson, Tobias, 1986, et al.
(författare)
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Biorthogonal modulation in 8 dimensions experimentally implemented as 2PPM-PS-QPSK
- 2014
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Ingår i: Optical Fiber Communication Conference, OFC 2014. - Washington, D.C. : OSA. - 9781557529930 ; , s. Art. no. 6886984-
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Konferensbidrag (refereegranskat)abstract
- We experimentally demonstrate biorthogonal modulation in 8 dimensions as binary pulse-position modulation polarization-switched QPSK. We compare this format with PM-QPSK at the same bit rate and show a 1.4 dB sensitivity gain and 84 % increased transmission distance.
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| 2. |
- Eriksson, Tobias, 1986, et al.
(författare)
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Experimental comparison of PS-QPSK and LDPC-coded PM-QPSK with equal spectral efficiency in WDM transmission
- 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. 6964035-
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Konferensbidrag (refereegranskat)abstract
- We compare QPSK with a rate 0.75 LDPC-code and PS-QPSK, which have the same spectral efficiency, in long-haul WDM transmission. We show that LDPC-coded PM-QPSK can achieve up to 98% increased transmission distance over uncoded PS-QPSK at BER = 10-3.
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| 3. |
- Eriksson, Tobias, 1986, et al.
(författare)
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K-Over-L Multidimensional Position Modulation
- 2014
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 32:12, s. 2254-2262
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Tidskriftsartikel (refereegranskat)abstract
- We analyze a family of modulation formats based on multidimensional position modulation (MDPM) with multiple pulses per frame (K-over-L-MDPM) in combination with quadrature phase shift keying (QPSK), polarization multiplexed QPSK (PM-QPSK) and polarization-switched QPSK (PS-QPSK) for coherent communication systems. MDPM is a generalization of pulse position modulation where different pulse slots can be realized by time slots, polarization states, frequencies, modes of multimode fibers, cores in multicore fibers or a combination of these. We show that by using K-over-L-MDPM with QPSK, it is possible to simultaneously increase both the spectral efficiency and the asymptotic power efficiency over QPSK. We also identify K-ary inverse-MDPM (KiMDPM-QPSK) as the special case of K-over(K -1)-MDPM and show that 4iMDPM-QPSK has a 1.25 dB increased asymptotic power efficiency over QPSK with a maintained spectral efficiency.
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| 4. |
- Eriksson, Tobias, 1986
(författare)
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Multidimensional Modulation Formats for Coherent Optical Communication Systems
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Coherent optical receivers have enabled the use of multilevel modulation formats with high spectral efficiencies and long transmission reaches. Traditionally, modulation formats utilizing the two dimensions spanned by the amplitude and the phase of the signal have been dominating. This thesis is devoted to novel modulation formats exploring the possibilities of modulation formats in higher dimensional signal spaces to find formats with a good tradeoff between spectral efficiency and sensitivity.The work included in this thesis can be divided into two parts, experimental and theoretical. The first part includes experimental demonstrations of several four- and eight-dimensional modulation formats where the sensitivity as well as the performance in terms of transmission reach is evaluated and compared to conventional modulation formats. 128-level set-partitioning QAM (128-SP-QAM) is demonstrated with 50 % increased transmission distance over polarization-multiplexed 16-ary quadrature amplitude modulation (PM-16QAM). Binary pulse position modulation in combination with QPSK (2PPM-QPSK) is shown to achieve 40 % increased transmission reach over PM-QPSK. Further, the eight-dimensional modulation format frequency and polarization switched QPSK (4FPS-QPSK) is shown to have 84 % increased transmission reach over polarization-multiplexed quadrature phase-shift keying (PM-QPSK) in a dual-carrier setup.The second part includes theoretical work where the spectral efficiency and asymptotic power efficiency is evaluated for modulation formats in high dimensional signal spaces. The high dimensionality is achieved by considering multidimensional position modulation, which is a generalization of pulse position modulation, in combination with QPSK and polarization-switched QPSK. The different dimensions can be achieved by time slots, polarizations, frequency slots, modes of multimode fibers or cores of a multicore fiber.
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| 5. |
- Johannisson, Pontus, 1976, et al.
(författare)
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Four-Dimensional Modulation Formats for Long-Haul Transmission
- 2014
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Ingår i: Optical Fiber Communication Conference, OFC 2014. - Washington, D.C. : OSA. - 9781557529930 ; , s. Art. no. 6886527-
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Konferensbidrag (refereegranskat)abstract
- A number of four-dimensional modulation formats are described theoretically and from an implementation point of view. The requirements for digital signal processing and the trade-off between spectral efficiency and receiver sensitivity is discussed.
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| 6. |
- Olid, Carolina, et al.
(författare)
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The effects of temperature and nitrogen and sulfur additions on carbon accumulation in a nutrient-poor boreal mire : decadal effects assessed using 210Pb peat chronologies
- 2014
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Ingår i: Journal of Geophysical Research - Biogeosciences. - : American Geophysical Union (AGU). - 2169-8953 .- 2169-8961. ; 119:3, s. 392-402
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Tidskriftsartikel (refereegranskat)abstract
- Boreal peatlands are a major long-term reservoir of atmospheric carbon (C) and play an important role in the global C cycle. It is unclear how C accumulation in peatlands responds to changing temperatures and nutrients (specifically, nitrogen and sulfur). In this study, we assessed how the C input rate and C accumulation rate in decadal old peat layers respond to increased air temperatures (+3.6 degrees C) during the growing season and the annual additions of nitrogen (N) and sulfur (S) (30 and 20kgha(-1)yr(-1), respectively) over 12years of field treatments in a boreal mire. An empirical mass balance model was applied to Pb-210-dated peat cores to evaluate changes in C inputs, C mass loss, and net C accumulation rates in response to the treatments. We found that (i) none of the treatments generated a significant effect on peat mass loss decay rates, (ii) C input rates were positively affected by N additions and negatively affected by S additions, (iii) the C accumulation rate in the uppermost (10 to 12cm) peat was increased by N additions and decreased by S additions, and (iv) only air temperature significantly affected the main effects induced by N and S additions. Based on our findings, we argue that C accumulation rates in surface peat layers of nutrient-poor boreal mires can increase despite the predicted rise in air temperatures as long as N loads increase and acid atmospheric S remains low. Key Points C accumulation in nutrient-poor boreal peatlands is increased by N fertilization Weak effects on C accumulation induced by greenhouse warming
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| 7. |
- Olsson, Samuel L I, 1984, et al.
(författare)
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Linear and nonlinear transmission of 16-QAM over 105 km phase-sensitive amplified link
- 2014
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Ingår i: Technical Digest Series: Optical Fiber Communication Conference, OFC 2014; San Francisco, CA; United States; 9 March 2014 through 13 March 2014. - Washington, D.C. : OSA. - 2162-2701. - 9781557529930
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Konferensbidrag (refereegranskat)abstract
- We demonstrate 16-QAM transmission over a 105 km phase-sensitive amplified link showing significantly improved performance in both the linear and nonlinear propagation regime. Constellation and BER measurements are performed.
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| 8. |
- Puttnam, Benjamin, et al.
(författare)
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Energy efficient modulation formats for multi-core fibers
- 2014
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Ingår i: 19th OptoElectronics and Communications Conference, OECC 2014 and the 39th Australian Conference on Optical Fibre Technology, ACOFT 2014; Melbourne, VIC; Australia; 6 - 10 Jul. 2014. - 9781922107213 ; , s. 694-696
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Konferensbidrag (refereegranskat)abstract
- We propose and experimentally investigate a family of multi-dimensional modulation formats for multi-core-fibers. Such formats can have power or spectral efficiency advantages or lower symbol energies but implementation difficulties cause an OSNR penalty.
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| 9. |
- Puttnam, Benjamin, et al.
(författare)
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Modulation formats for multi-core fiber transmission
- 2014
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 22:26, s. 32457-32469
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Tidskriftsartikel (refereegranskat)abstract
- ©2014 Optical Society of America We investigate high dimensional modulation formats for multi-core fibers (MCFs) and spatial superchannels. We show that the low skew variations between MCF cores maybe exploited to generate 'multi-core' formats that offer significant advantages over independently transmitting conventional 4-dimensional formats in each core. We describe how pulse position modulation formats may be transposed to the spatial domain and then investigate a family of modulation formats referred to as core-coding, one of which has the same power and spectral efficiency as polarization switched quaternary phase shift keying but with half of the optical power, potentially improving non-linear tolerance for long distance transmission, albeit at the cost of implementation challenges. Finally, we investigate the application of set-partitioning to multi-core formats using a single-parity check bit transmitted in one quadrature of one polarization in one of the cores and polarization-division multiplexing quadrature phase shift keying data in all remaining cores. We observe that for high core counts, an advantage of almost 3 dB in asymptotic power efficiency may be obtained with negligible impact on spectral efficiency, which translates into experimentally measured reduction in the required optical signal-to-noise ratio of up to 1.8 dB at a bit-error-rate of 10-5 and the same data-rate, and additional transmission reach of up to 20%.
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| 10. |
- Puttnam, Benjamin, et al.
(författare)
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Single parity check multi-core modulation for power efficient spatial super-channels
- 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. 6964197-
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Konferensbidrag (refereegranskat)abstract
- We investigate multi-core modulation formats for spatial super-channels using a single parity check on PDM-QPSK symbols. Compared to per-core PDM-QPSK, we show improvements in required OSNR of up to 1.8 dB, with minimal impact on spectral efficiency.
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