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Proceedings Paper

10-Gbit/s electroabsorption modulator lasers (EMLs) for long-span transmission
Author(s): Randal A. Salvatore; Richard T. Sahara
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Paper Abstract

Development toward a low-cost 10Gbit/s module is presented. We focus on four key issues for transmission lasers: 1) Optical sources with integrated laser and modulator often involve four our more separate growths. We demonstrate a strain-compensated AlGaIn-As-based monolithic source with uses a single overgrowth. EMLs with a complex-coupled DFB grating provide high sidemode suppression ration (SMSR>50dB), high single-mode yield, and excellent immunity to optical reflection. 2) A new method for characterizing complex-coupled gratings allows us to determine the gain-grating component of DFBs (or EMLs) beyond threshold. Gain grating strength will drop with spatial holeburning. This method allows one to measure gain-grating strength at any power. 3) We investigate the effect of reflection-induced chirp. Theory and experiment show that EMLs and other integrated photonic sources can be 100-1000 times more resistant to feedback if a strong (κrL=6) grating is used instead of the type of gratings typically used. This supports the growing trend that isolator-free transmission lasers are practical. It also permits integration of amplifiers or other elements with the laser. 4) Chirp-free transmission is non-optimum for long-span transmission. A number of different types of fiber currently exist, and EMLS can be made with the capability of adjustable chirp. Thus, a single EML can suit each of these fiber types (e.g. SMF-28, LEAF, zero-dispersion, and MetroCor). We investigate the effects of dispersion on non-return-to-zero (NRZ) data from these EMLs. Bit error ratios (BER) are theoretically and experimentally analyzed for optimum chirp for long spans without dispersion-compensation.

Paper Details

Date Published: 4 December 2002
PDF: 13 pages
Proc. SPIE 4871, Semiconductor Lasers and Optical Amplifiers for Lightwave Communication Systems, (4 December 2002); doi: 10.1117/12.455642
Show Author Affiliations
Randal A. Salvatore, Corning Lasertron, Inc. (United States)
Richard T. Sahara, Corning Lasertron, Inc. (United States)

Published in SPIE Proceedings Vol. 4871:
Semiconductor Lasers and Optical Amplifiers for Lightwave Communication Systems
Richard P. Mirin; Carmen S. Menoni, Editor(s)

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