High-speed 850-nm VCSELs for 40 Gb/s transmission
Konferensbidrag (offentliggjort, men ej förlagsutgivet), 2010

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 < 10 -12 ) under direct modulation at a record-high bit-rate of 32 Gb/s over 50 m of OM3 fiber at room temperature, and at 25 Gb/s over 100 m of OM3 fiber at 85 °C. We also demonstrate transmission at 40 Gb/s over 200 m of OM3+ fiber at room temperature using a subcarrier multiplexing scheme with a spectrally efficient 16 QAM modulation format. All transmission results were obtained with the VCSEL biased at current densities between 11-14 kA/cm 2 , which is close to the 10 kA/cm 2 industry benchmark for reliability. Finally, we show that by a further reduction of the oxide capacitance and by reducing the photon lifetime using a shallow surface etch, a record bandwidth of 23 GHz for 850 nm VCSELs can be reached. © 2010 SPIE.

Vertical cavity surface emitting laser

High speed

Subcarrier multiplexing

Transmission

Differential gain

Electrical parasitics

Författare

Johan Gustavsson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

Petter Westbergh

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

Krzysztof Szczerba

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

Åsa Haglund

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

Anders Larsson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

Magnus Karlsson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

Peter Andrekson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

Friedhelm Hopfer

Technische Universität Berlin

Gerrit Fiol

Technische Universität Berlin

Dieter Bimberg

Technische Universität Berlin

Bengt-Erik Olsson

Ericsson Microwave Systems AB

Anna Kristiansson

Ericsson Microwave Systems AB

S. B. Healy

Tyndall National Institute at National University of Ireland, Cork

E. P. O'Reilly

Tyndall National Institute at National University of Ireland, Cork

Anders Larsson

IQE Europe Ltd.

Proceedings of SPIE - The International Society for Optical Engineering

0277786X (ISSN)

Vol. 7720 772002

Ämneskategorier

Fysik

DOI

10.1117/12.854516

ISBN

978-081948193-1