Compact and Low-Power-Consumption 40-Gbit/s, 1.55-µm Electro-Absorption Modulators

Hideo ARIMOTO
Jun-ichiro SHIMIZU
Takeshi KITATANI
Kazunori SHINODA
Tomonobu TSUCHIYA
Masataka SHIRAI
Masahiro AOKI
Noriko SASADA
Hiroshi YAMAMOTO
Kazuhiko NAOE
Mitsuo AKASHI

Publication
IEICE TRANSACTIONS on Electronics   Vol.E88-C    No.5    pp.951-959
Publication Date: 2005/05/01
Online ISSN: 
DOI: 10.1093/ietele/e88-c.5.951
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Joint Special Section on Recent Progress in Optoelectronics and Communications)
Category: Optical Active Devices and Modules
Keyword: 
40-Gbit/s,  electro-absorption modulator,  InGaAsP,  InGaAlAs,  EAM/DFB laser,  uncooled operation,  

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Summary: 
This paper describes 40-Gbit/s operation of 1.55-µm electro-absorption (EA) modulators applicable to compact and low-cost transmitters for very-short-reach (VSR) applications. We start by identifying factors that make a multi-quantum-well (MQW) design suitable for high levels of output power and for uncooled operation. From the basic experimental results, we determine that a valence-band discontinuity ΔEv at around 80 meV is optimal in terms of combining high-output-power operation and a good extinction ratio. We then apply the above findings in an InGaAsP-MQW EA modulator that is monolithically integrated with a distributed feedback (DFB) laser, and thus obtain operation with high output power (+1.2 dBm), a high ER (10.5 dB), and a low power penalty (0.4 dB after transmission over 2.6 km of single-mode-fiber). These results confirm the applicability of our EA modulator/DFB laser to VSR applications. After that, we theoretically demonstrate the superiority in terms of ER characteristics of the InGaAlAs-MQW over the conventional InGaAsP-MQW. InGaAlAs-MQW EA modulators are fabricated and demonstrate, for the first time, 40-Gbit/s operation over a wide temperature range (0 to 85).