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Proceedings Paper

Improvement of kink characteristic of proton-implanted VCSEL with ITO overcoating
Author(s): Fang-I Lai; Ya-Hsien Chang; Li-Hong Laih; Hao-chung Kuo; S. C. Wang
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Paper Abstract

Proton implanted VCSEL has been demonstrated with good reliability and decent modulation speed up to 1.25 Gb/s. However, kinks in current vs light output (L-I) has been always an issue in the gain-guided proton implant VCSEL. The kink related jitter and noise performance made it difficult to meet 2.5 Gb/s (OC-48) requirement. The kinks in L-I curve can be attributed to non-uniform carrier distribution induced non-uniform gain distribution within emission area. In this paper, the effects of a Ti/ITO transparent over-coating on the proton-implanted AlGaAs/GaAs VCSELs (15um diameter aperture) are investigated. The kinks distribution in L-I characteristics from a 2 inch wafer is greatly improved compared to conventional process. These VCSELs exhibit nearly kink-free L-I output performance with threshold currents ~3 mA, and the slope efficiencies ~ 0.25 W/A. The near-field emission patterns suggest the Ti/ITO over-coating facilitates the current spreading and uniform carrier distribution of the top VCSEL contact thus enhancing the laser performance. Finally, we performed high speed modulation measurement. The eye diagram of proton-implanted VCSELs with Ti/ITO transparent over-coating operating at 2.125 Gb/s with 10mA bias and 9dB extinction ratio shows very clean eye with jitter less than 35 ps.

Paper Details

Date Published: 16 June 2004
PDF: 8 pages
Proc. SPIE 5364, Vertical-Cavity Surface-Emitting Lasers VIII, (16 June 2004); doi: 10.1117/12.530023
Show Author Affiliations
Fang-I Lai, National Chiao Tung Univ. (Taiwan)
Ya-Hsien Chang, National Chiao Tung Univ. (Taiwan)
Li-Hong Laih, National Chiao Tung Univ. (Taiwan)
Hao-chung Kuo, National Chiao Tung Univ. (Taiwan)
S. C. Wang, National Chiao Tung Univ. (Taiwan)

Published in SPIE Proceedings Vol. 5364:
Vertical-Cavity Surface-Emitting Lasers VIII
Chun Lei; Kent D. Choquette; Sean P. Kilcoyne, Editor(s)

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