| 1. |
- Gustavsson, Johan, 1974, et al.
(författare)
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High speed 850nm VCSELs for >40Gb/s transmission
- 2013
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Ingår i: 2013 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, OFC/NFOEC 2013. - 9781479904570 ; , s. OTh4H.4-
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Konferensbidrag (refereegranskat)abstract
- VCSELs capable of direct modulation exceeding 40Gb/s are needed in next generation optical interconnect standards. Using a refined high-speed design we demonstrate GaAs-based VCSELs having record-high 28GHz modulation bandwidth, and that operate error-free at 47Gb/s.
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| 2. |
- Gustavsson, Johan, 1974, et al.
(författare)
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High-speed, high-temperature VCSELs for optical interconnects
- 2013
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Ingår i: 2013 IEEE Photonics Society Summer Topical Meeting Series, PSSTMS 2013. - 9781467350600 ; , s. 7-8
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Konferensbidrag (refereegranskat)abstract
- Directly modulated VCSELs operating at 40Gb/s are required for next generation optical interconnect standards. Using a refined high-speed design we demonstrate GaAs-based VCSELs that operate error-free at 47Gb/s at 25°C, and 40Gb/s at 85°C.
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| 3. |
- Haglund, Erik, 1985, et al.
(författare)
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850 nm datacom VCSELs for higher-speed and longer-reach transmission
- 2013
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Ingår i: European VCSEL Day 2013.
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Konferensbidrag (refereegranskat)abstract
- The 850 nm GaAs-based VCSEL is already the dominating technology for transmitters in optical interconnects up to 100 m in datacenters, thanks to low-cost fabrication, excellent high-speed properties at low currents and the existence of high-speed OM4 multimode fiber optimized for this particular wavelength. Future datacenters will require faster and more energy-efficient VCSELs to increase the overall bandwidth and reduce the power consumption of the datacenter network. In addition, longer-reach interconnects exceeding 1 km will also be required as datacenters grow into large multi-building complexes.By optimizing the doping profiles of the DBRs to reduce resistance, using a short (½-λ) cavity to improve longitudinal optical confinement and optimizing the photon lifetime for optimal damping, we obtained a record-high small-signal modulation bandwidth of 28 GHz for a ~4 µm oxide aperture VCSEL. A 7 µm oxide aperture VCSEL (~27 GHz bandwidth) enabled error-free transmission (bit-error-rate 300 m), the large spectral width of VCSELs leads to severe signal degradation by fiber dispersion. We have investigated two methods of fabricating low-spectral width quasi-single mode VCSELs to mitigate this problem. By using a small oxide aperture of ~3 µm, error-free transmission was achieved at 22 Gbit/s over 1.1 km of OM4 fiber. An alternative approach is to use an integrated mode filter in the form of a shallow surface relief to reduce the spectral width of the VCSEL. The mode filter allows for the use of a larger oxide aperture and thereby enables a lower resistance and operation at a lower current density. A 5 µm oxide aperture VCSEL with a mode filter enabled error-free transmission at 25 Gbit/s over 500 m of OM4 fiber.
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| 4. |
- Haglund, Erik, 1985, et al.
(författare)
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High-speed lasers for optical interconnects
- 2012
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Ingår i: Swedish Optics and Photonics Days 2012.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the era of cloud computing, with services such as video streaming, social networking, and online storage and file sharing, the demand for online data processing and storage capacity is growing rapidly. These services are hosted in huge data centers that need not only fast servers but also fast communication between servers. Because copper cables have high attenuation at high frequencies, the most promising solution is to use fiber optical links (called optical interconnects) to connect different parts of the data center. Today, gallium arsenide-based vertical-cavity surface-emitting lasers (VCSELs) emitting at 850 nm are the standard light source in transmitters used in commercially available optical interconnects, operating at up to 14 Gbit/s with a link length of up to 300 m. These lasers have the advantages of low power consumption, fast direct modulation at low currents, and low-cost manufacturing. To keep up with the demand of increasing optical interconnect capacity, the Photonics Laboratory at Chalmers university of Technology is conducting research into improving the speed, reach and capacity of VCSELs for optical interconnects.
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| 5. |
- Haglund, Erik, 1985, et al.
(författare)
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Quasi-single mode VCSELs for longer-reach multimode fiber optical interconnects
- 2014
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Ingår i: Summers School on Optical Interconnects, 3-6 June 2014, Thessaloniki.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Longer-reach (>300 m) optical interconnects are needed asdatacenters grow ever larger. Today the reach of 850 nmVCSEL-based optical interconnects is mainly limited by fiber dispersion. By reducing the spectral width of the VCSEL, the effects of fiber dispersion may be reduced, effectively increasing the error-free transmission distance.
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| 6. |
- Karppinen, Mikko, et al.
(författare)
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Integration of 150 Gbps/fiber optical engines based on multicore fibers and 6-channel VCSELs and PDs
- 2016
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9781628419887 ; 9753, s. Art. no. 97530S-
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Konferensbidrag (refereegranskat)abstract
- Multicore fiber enables a parallel optic data link with a single optical fiber, thus providing an attractive way to increase the total throughput and the integration density of the interconnections. We study and present photonics integration technologies and optical coupling approaches for multicore transmitter and receiver subassemblies. Such optical engines are implemented and characterized using multimode 6-core fibers and multicore-optimized active devices: 850-nm VCSEL and PD arrays with circular layout and multi-channel driver and receiver ICs. They are developed for bit-rates of 25 Gbps/channel and beyond, i.e.
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| 7. |
- 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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| 8. |
- Safaisini, Rashid, 1981, et al.
(författare)
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20 Gbit/s data transmission over 2 km multimode fibre using 850 nm mode filter VCSEL
- 2014
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 50:1, s. 40-42
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Tidskriftsartikel (refereegranskat)abstract
- Error-free data transmission over 1.3 and 2 km multimode fibre at 25 and 20 Gbit/s, respectively, is demonstrated using a high-speed, single-mode, 850 nm vertical-cavity surface-emitting laser (VCSEL) with an integrated mode filter. This result represents a bitrate-distance product of 40 Gbit/s km, a new record for multimode fibre VCSELbased interconnects.
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| 9. |
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| 10. |
- Safaisini, Rashid, 1981, et al.
(författare)
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22 Gb/s error-free data transmission beyond 1 km of multi-mode fiber using 850 nm VCSELs
- 2013
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9780819494085 ; 8639
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Konferensbidrag (refereegranskat)abstract
- The first error-free data transmission beyond 1 km of multi-mode fiber at bit-rates exceeding 20 Gb/s is demonstrated using a high modulation bandwidth, quasi-single mode (SMSR similar to 20 dB) 850 nm VCSEL. A VCSEL with small similar to 3 mu m aperture shows quasi-single mode operation with a narrow spectral width. The top mirror reflectivity of the VCSEL is optimized for high speed and high output power by shallow etching. A combination of narrow spectral width and high optical power reduces the effects of fiber dispersion and fiber and connector losses and enables such a long transmission distance at high bit-rates.
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