dc.description.abstract | In this dissertation, the researches focus on the high-speed multi-channel short-reach (SR) optical engine platform development based on the silicon optical bench (SiOB) technologies. As the rapid development of cloud computing and upcoming high-speed link expectation for portable devices, how to drive the optical interconnect technology to higher speed, multi-channels, miniaturization, and even low costs in mass production has become the research hot zone, where the SiOB technology has been received with great attentions on completing the OE/EO converter. SiOB-based optical engine can be conducted via silicon Micro Electro Mechanical Systems (MEMS) process, leading to high structural accuracy up to few micron-meters, precisely packaging among micro-optical elements, such as VCSEL/PD and MMFs, and cost competitive advantages in mass batch production.
In first research topic, a 4-channel x 10-Gbps optical interconnect module based on a SiOB with a 45 degree reflector as well as monolithic V-groove array for fiber alignment is developed. The 4-channel VCSEL and PD arrays are flip-chip assembled onto the pedestal of SiOB using Au/Sn eutectic solder bumps to form a SiOB-based bi-directional optical sub-assembly (BOSA) configuration. In a 4 mm × 3.75 mm × 0.6 mm small size, 4-Tx and 4-Rx channels can be completed, bringing into physical size advantage for portable cables with optical link. The optical coupling of VCSEL-to-MMF and MMF-to-PD without adding coupled optics is -5.2 and -2 dB, respectively. The widely alignment tolerances of 1-dB power variation for the transmitting and receiver parts are 15-?m are achieved. The clearly open 10-Gbps eye patterns of Tx part as well as BER of 10-12 . The Rx sensitivity can reach to as low as -12 dBm as input optical power with channel cross-talk enabled. The research study starts from wafer process, chip-level packaging, PCB circuit and chip-on-board assembly, fiber mounting, to highs-speed testing, and also industrial reliability testing applied. The results indicate this SiOB optical engine can be a fundamental platform for versatile optical interconnect applications with high-speed and compact OE/EO module.
In the last part of this dissertation, a polymer waveguide technology has been to apply into this SiOB platform. To providing more optical layout flexibility and also, the upcoming 25-Gbps optical link with tougher optical coupling requirement due to the smaller sensing area of PD or larger NA of VCSEL, polymer waveguide can play an important role to overcome these issues. A multi-channels OE/EO module with polymer waveguide on SiOB has been successfully realized with optical link by fiber coupled. The polymer waveguide can be fabricated onto the SiOB with standard lithography process, whose core size is approx. up to 40-?m scale with compatible size of MMF’s core. We believe this configuration can be a basis for future more compact size OE module or higher speed optical interconnects applications.
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