| 1. |
- Bickham, S., et al.
(författare)
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Low cutoff G.657-compatible fiber for data center interconnects operating in the 1064 and 1310 nm windows
- 2020
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 11286
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Konferensbidrag (refereegranskat)abstract
- Optical interconnects in data centers have traditionally used 850 nm GaAs-based vertical-cavity surface-emitting lasers (VCSELs) in combination with multimode fiber, having a reach up to 100 m in length. Longer links typically use standard single-mode fiber in conjunction with either InP-based edge-emitting lasers or silicon photonic transmitters operating in the 1310 nm or 1550 nm window. Single-mode GaAs-based VCSELs operating at 1064 nm offer another path for achieving longer system reach. Potential advantages of these VCSELs include better power efficiency, modulation speeds reaching 50 Gbps and large-scale fabrication volumes. The longer wavelength is also beneficial due to the lower attenuation and chromatic dispersion of optical fibers at that wavelength. However, one practical issue for single-mode transmission is that the G.657 standard for single-mode fiber requires that the 22-meter cable cutoff wavelength be less than 1260 nm, and these fibers are typically few-moded at 1064 nm. The large differences between the group velocities of the LP01 and LP11 modes can lead to degradation of the system performance due to multi-path interference if the higher order modes are present. To resolve this quandary, we have designed and validated the performance of a new optical fiber which is single-moded at wavelengths less than 1064 nm, but also has G.657-compliant mode field diameter and dispersion characteristics that enable it to be used in the 1310 nm window.
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| 2. |
- Larsson, Anders, 1957, et al.
(författare)
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1060 nm VCSELs for long-reach optical interconnects
- 2018
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Ingår i: Optical Fiber Technology. - : Elsevier BV. - 1095-9912 .- 1068-5200. ; 44, s. 36-42
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Tidskriftsartikel (refereegranskat)abstract
- Reach extension of high capacity optical interconnects based on vertical-cavity surface-emitting lasers (VCSELs) and multimode fibers (MMFs), as needed for large-scale data centers, would benefit from high-speed GaAs-based VCSELs at 1060 nm. At this wavelength, the chromatic dispersion and attenuation of the optical fiber are much reduced in comparison with 850 nm. We present single and multimode 1060 nm VCSELs based on designs derived partly from our high-speed 850 nm VCSEL designs. The single-mode VCSEL, with a modulation bandwidth exceeding 22 GHz, supports back-to-back data rates up to 50 Gbps at 25 °C and 40 Gbps at 85 °C under binary NRZ (OOK) modulation. Using mode-selective launch, we demonstrate error-free 25 Gbps transmission over 1000 m of 1060 nm optimized MMF. Higher data rates and/or longer distances will be possible with equalization, forward-error-correction, and/or multilevel modulation.
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| 3. |
- Larsson, Anders, 1957, et al.
(författare)
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High-Speed VCSELs for Datacom
- 2016
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Ingår i: Proceedings European Conference on Optical Communication. - 9783800742745 ; , s. 977-979
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Konferensbidrag (refereegranskat)
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| 4. |
- Larsson, Anders, 1957, et al.
(författare)
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High-Speed VCSELs for OOK and Multilevel PAM Modulation
- 2017
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Ingår i: 30TH ANNUAL CONFERENCE OF THE IEEE PHOTONICS SOCIETY (IPC). - 2374-0140. - 9781509065783 ; 2017-January, s. 355-356
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Konferensbidrag (refereegranskat)abstract
- The short-reach optical interconnects used in datacenters and high-performance computing systems are dominated by vertical-cavity surface-emitting laser (VCSEL) and multimode fiber (MMF) links1. The VCSEL-MMF technology is the most cost and power efficient and offers the smallest footprint. VCSELs for 25-28 Gbit/s OOK lanes are in production2 while 25-28 Gbaud PAM-4 with forward-error-correction (FEC) is considered for next generation 50-56 Gbit/s lanes3. For this transition, as well as future developments towards even higher speed, the VCSEL dynamics and high-speed properties are of utmost importance. Improved dynamics may enable 50-56 Gbit/s PAM-4 without FEC and even 50-56 Gbit/s OOK, which would reduce complexity, power consumption, and latency.
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| 5. |
- Larsson, Anders, 1957, et al.
(författare)
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VCSEL design and integration for high-capacity optical interconnects
- 2017
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9781510606593 ; 10109, s. 101090M-
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Konferensbidrag (refereegranskat)abstract
- Vertical-cavity surface-emitting lasers and multi-mode fibers is the dominating technology for short-reach optical interconnects in datacenters and high performance computing systems at current serial rates of up to 25-28 Gbit/s. This is likely to continue at 50-56 Gbit/s. The technology shows potential for 100 Gbit/s.
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| 6. |
- Larsson, Anders, 1957, et al.
(författare)
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VCSEL modulation capacity: Continued improvements or physical limits?
- 2017
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Ingår i: 6th IEEE Photonics Society Optical Interconnects Conference, OI 2017. - 9781509050154 ; , s. 53-54
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Konferensbidrag (refereegranskat)abstract
- The short-reach optical interconnects used in datacenters and high-performance computing systems are dominated by VCSEL and multimode fiber (MMF) links 1 . The VCSEL-MMF technology is the most cost and power efficient and offers the smallest footprint. VCSELs operating at 25-28 Gbit/s are in production 2 while research has extended the VCSEL modulation bandwidth to 30 GHz 3 (Fig.1) and enabled OOK-NRZ data transmission up to 57 Gbit/s at 25°C 4 and 50 Gbit/s at 85°C 5 , without equalization or forward-error-correction (FEC). A VCSEL energy dissipation below 100 fJ/bit has been demonstrated at 25-50 Gbit/s 3 (Fig.1). The need for higher interconnect capacity raises the question whether the speed and dynamics of VCSELs can be further improved or whether physical limits preventing this have been reached. Higher speed VCSELs would enable higher lane rates and therefore reduced number of lanes and increased bandwidth density for a given aggregate interconnect capacity.
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| 7. |
- Larsson, Anders, 1957, et al.
(författare)
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VCSEL modulation speed: Status and prospects
- 2019
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 10938
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Konferensbidrag (refereegranskat)
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| 8. |
- Lavrencik, Justin, et al.
(författare)
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Error-Free 100Gbps PAM-4 Transmission over 100m OM5 MMF using 1060nm VCSELs
- 2019
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Ingår i: Optics InfoBase Conference Papers. - 2162-2701. ; Part F160-OFC 2019
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Konferensbidrag (refereegranskat)abstract
- We experimentally demonstrate error-free (BER <10 -12 ) rates beyond 100Gbps over 100m OM5 using unpackaged 1060nm VCSELs. Power penalties of PAM-2/PAM-4 are examined demonstrating OM5 fiber capacity to support wavelengths to 1060nm with only transmitter equalization.
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| 9. |
- Lavrencik, Justin, et al.
(författare)
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Error-free 850nm to 1060nm VCSEL links: Feasibility of 400Gbps and 800Gbps 8λ-SWDM
- 2019
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Ingår i: IET Conference Publications. - 9781839530074 ; 2019
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Konferensbidrag (refereegranskat)abstract
- We demonstrate effective transmitter equalization for 850nm, 980nm, and 1060nm VCSELs and 100m OM5 links enabling 78Gbps PAM-2 and >100Gbps PAM-4 100m error free links. Extracted link penalties reveal net fibre dispersion and RIN enhancement create small to negligible power penalties for all wavelengths.
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| 10. |
- Lengyel, Tamas, 1986, et al.
(författare)
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Pre-emphasis enabled 50 Gbit/s transmission over 1000 m SMF using a 1060 nm single-mode VCSEL
- 2018
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 54:20, s. 1186-1187
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Tidskriftsartikel (refereegranskat)abstract
- A single-mode 1060 nm vertical-cavity surface-emitting laser (VCSEL) and single-mode fibre (SMF) based link with two-tap active pre-emphasis enabling error-free transmission of 50 Gbit/s NRZ-OOK over 1000 m is presented.
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