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High speed low current density 850 nm VCSELs

Anders Larsson (Institutionen för mikroteknologi och nanovetenskap, Fotonik) ; Petter Westbergh (Institutionen för mikroteknologi och nanovetenskap, Fotonik) ; Johan S. Gustavsson (Institutionen för mikroteknologi och nanovetenskap, Fotonik) ; Åsa Haglund (Institutionen för mikroteknologi och nanovetenskap, Fotonik)
Proceedings of SPIE-The International Society for Optical Engineering (0277-786X). Vol. 7615 (2010), p. 761505-1-11.
[Konferensbidrag, refereegranskat]

The design of an oxide confined 850 nm VCSEL has been engineered for high speed operation at low current density. Strained InGaAs/AlGaAs QWs, with a careful choice of In and Al concentrations based on rigorous band structure and gain calculations, were used to increase differential gain and reduce threshold carrier density. Various measures, including multiple oxide layers and a binary compound in the lower distributed Bragg reflector, were implemented for reducing capacitance and thermal impedance. Modulation bandwidths > 20 GHz at 25°C and > 15 GHz at 85°C were obtained. At room temperature, the bandwidth was found to be limited primarily by the still relatively large oxide capacitance, while at 85°C the bandwidth was also limited by the thermal saturation of the resonance frequency. Transmission up to 32 Gb/s (on-off keying) over multimode fiber was successfully demonstrated with the VCSEL biased at a current density of only 11 kA/cm2. In addition, using a more spectrally efficient modulation format (16 QAM sub-carrier multiplexing), transmission at 40 Gb/s over 200 m multimode fiber was demonstrated.

Nyckelord: vertical cavity surface emitting laser, high speed, differential gain, electrical parasitics, transmission, subcarrier multiplexing

Denna post skapades 2010-12-01. Senast ändrad 2016-04-11.
CPL Pubid: 129930


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Institutioner (Chalmers)

Institutionen för mikroteknologi och nanovetenskap, Fotonik



Chalmers infrastruktur