| 1. |
- Szczerba, Krzysztof, 1985, et al.
(författare)
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Impact of Forward Error Correction on Energy Consumption of VCSEL-based Transmitters
- 2015
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Ingår i: 41st European Conference on Optical Communication, ECOC 2015, Valencia, Spain, 27 September - 1 October 2015. - 9788460817413 ; 2015-November
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Konferensbidrag (refereegranskat)abstract
- We present an analysis of the effect of FEC on energy consumption of VCSEL based transmitters for short-range optical links. We show that a low-complexity FEC can reduce the overall energy consumption of the transmitter.
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| 2. |
- Gustavsson, Johan, 1974, et al.
(författare)
-
High-speed 850-nm VCSELs for 40 Gb/s transmission
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)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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| 3. |
- Larsson, Anders, 1957, et al.
(författare)
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High speed VCSELs for optical interconnects
- 2012
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Ingår i: Conference Proceedings - International Conference on Indium Phosphide and Related Materials. - 1092-8669. - 9781467317252 ; , s. 269-272
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Konferensbidrag (refereegranskat)abstract
- This paper presents an overview of our recent work on high speed, oxide confined, 850 nm vertical cavity surface emitting lasers (VCSELs). With proper active region and cavity designs, and techniques for reducing capacitance and thermal impedance, we have reached a modulation bandwidth of 23 GHz and demonstrated 40 Gbps transmission. Using an integrated mode filter for reducing the spectral width we have extended the reach on multimode fiber at 25 Gbps from 100 to 500 m. Improved link capacity was also demonstrated using a more spectrally efficient multi-level modulation format (4-PAM). Finally, a MEMS-technology for wafer scale integration of tunable high speed VCSELs was developed, enabling a tuning range of 24 nm, a 6 GHz modulation bandwidth, and 5 Gbps transmission.
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| 4. |
- Larsson, Anders, 1957, et al.
(författare)
-
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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| 5. |
- Lengyel, Tamas, 1986, et al.
(författare)
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Impact of Damping on 50 Gbps 4-PAM Modulation of 25G Class VCSELs
- 2017
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 35:19, s. 4203-4209
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Tidskriftsartikel (refereegranskat)abstract
- We present an investigation into the effects of photon lifetime and the associated damping of the modulation response on 50 Gbps 4-PAM signal generation with directly modulated 25G class VCSELs. While 4-PAM benefits from higher slope efficiency and output power, it is shown that the greater impact of intensity noise and dynamic nonlinearities implies that a VCSEL with a longer photon lifetime and more damped response is needed when transitioning from existing 25 Gbps OOK to 50 Gbps 4-PAM using the 25G VCSEL technology.
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| 6. |
- Lengyel, Tamas, 1986, et al.
(författare)
-
Sensitivity Improvements in an 850 nm VCSEL-based Link using a Two-tap Pre-emphasis Electronic Filter
- 2016
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 35:9, s. 1633-1639
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Tidskriftsartikel (refereegranskat)abstract
- We present an investigation of an ISI penalty reduction for On-Off Keying in an 850 nm VCSEL-based short optical link using a two-tap electronic pre-emphasis filter and quantify the improvement relative to an equivalent link without pre-emphasis. Error-free operation is demonstrated at bit rates above the −3 dB modulation bandwidth of the link. Sensitivity improvement up to 9 dB compared to non-emphasized signaling is shown. A maximum error-free bit rate achievable in the link is increased to 57 Gbps, compared to 52 Gbps without the pre-emphasis.
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| 7. |
- Lengyel, Tamas, 1986, et al.
(författare)
-
Sensitivity improvements in an 850 nm VCSEL transmitter using a one-tap pre-emphasis electronic filter
- 2015
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Ingår i: 41st European Conference on Optical Communication, ECOC 2015, Valencia, Spain, 27 September - 1 October 2015. - 9788460817413 ; 2015-November
-
Konferensbidrag (refereegranskat)abstract
- We present ISI reduction of an 850 nm VCSEL-based back-to-back optical link using a one-tap electronic pre-emphasis filter and compare it to a VCSEL link without filtering with similar launch conditions. Error floors are eliminated by the use of the filter.
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| 8. |
- Safaisini, Rashid, 1981, et al.
(författare)
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High-Speed 850 nm Quasi-Single Mode VCSELs for Extended Reach Optical Interconnects
- 2013
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Ingår i: Journal of Optical Communications and Networking. - 1943-0620 .- 1943-0639. ; 5:7, s. 686-695
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents recent results on high-speed, quasi-single-mode, 850 nm vertical-cavity surface-emitting lasers (VCSELs) with a narrow spectral width for extended-reach optical interconnects. The top mirror reflectivity is adjusted for high output power, slope efficiency, and small signal modulation bandwidth. An oxide confined VCSEL with an ∼3 μm aperture diameter delivers 2 mW of output power and reaches a resonance frequency as high as 25 GHz and a modulation bandwidth exceeding 20 GHz. A small K-factor of 0.17 ns and a large D-factor of 17.3 GHz/mA1/2, extracted from the VCSEL modulation response, along with the improved DC and modal properties enable energy-efficient data transmission at high bit rates over long-distance multimode fiber. Error-free transmission at bit rates exceeding 20 Gbits/s over 1.1 km of OM4 fiber is demonstrated and shown to be limited mainly by the photoreceiver bandwidth. A theoretical investigation of the dependence of link performance on photoreceiver bandwidth is also presented.
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| 9. |
- Szczerba, Krzysztof, 1985, et al.
(författare)
-
30 Gbps 4-PAM transmission over 200m of MMF using an 850 nm VCSEL
- 2011
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 19:26, s. B203-B208
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Tidskriftsartikel (refereegranskat)abstract
- We present high speed real time, error free 4-PAMtransmissionfor short range optical links based on a VCSEL operating at 850 nm, a multimode fibre and a simple intensity detector. Transmission speeds of 25 Gbps and 30 Gbps are demonstrated, and the maximum fibre reaches were 300 m and 200 m, respectively. The 4-PAM is also compared with OOK transmission at 25 Gbps, and we find that at this bit rate 4-PAM increases the error free transmission distance in the multimode fibre by 100 m, compared to OOK.
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| 10. |
- Szczerba, Krzysztof, 1985, et al.
(författare)
-
30 Gbps 4-PAM transmission over 200m of MMF using an 850 nm VCSEL
- 2011
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Ingår i: European Conference and Exposition on Optical Communications, ECOC. - 2162-2701. - 9781557529312 ; , s. 1-3
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Konferensbidrag (refereegranskat)abstract
- Real time, error free 4-PAM transmission at 25 Gbps and 30 Gbps over 300 m and200m of multimode fiber, respectively, using a VCSEL operating at the wavelength of 850 nm.
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