Comparison of Single-/Few-/Multi-mode 850 nm VCSELs for Optical OFDM Transmission
Journal
Optics Express
Journal Volume
25
Journal Issue
14
Pages
149-168
Date Issued
2017
Author(s)
Hsuan-Yun Kao
Cheng-Ting Tsai
Shan-Fong Leong
Chun-Yen Peng
Yu-Chieh Chi
Jian Jang Huang
Hao-chung Kuo
Tien-Tsorng Shih
Jau-Ji Jou
Wood-Hi Cheng
Chao-Hsin Wu
Gong-Ru Lin
林恭如
Abstract
For high-speed optical OFDM transmission applications, a comprehensive comparison of the homemade multi-/few-/single-transverse mode (MM/FM/SM) vertical cavity surface emitting laser (VCSEL) chips is performed. With microwave probe, the direct encoding of pre-leveled 16-QAM OFDM data and transmission over 100-m-long OM4 multi-mode-fiber (MMF) are demonstrated for intra-datacenter applications. The MM VCSEL chip with the largest emission aperture of 11 μm reveals the highest differential quantum efficiency which provides the highest optical power of 8.67 mW but exhibits the lowest encodable bandwidth of 21 GHz. In contrast, the SM VCSEL chip fabricated with the smallest emission aperture of only 3 μm provides the highest 3-dB encoding bandwidth up to 23 GHz at a cost of slight heat accumulation. After optimization, with the trade-off set between the receiving signal-to-noise ratio (SNR) and bandwidth, the FM VCSEL chip guarantees the highest optical OFDM transmission bit rate of 96 Gbit/s under back-to-back case with its strongest throughput. Among three VCSEL chips, the SM VCSEL chip with nearly modal-dispersion free feature is treated as the best candidate for carrying the pre-leveled 16-QAM OFDM data over 100-m OM4-MMF with same material structure but exhibits different oxide-layer confined gain cross-sections with one another at 80-Gbit/s with the smallest receiving power penalty of 1.77 dB.
SDGs
Type
journal article