Design and fabrication of a single line IQ modulator
Date
2018
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Publisher
University of Delaware
Abstract
As the demand for high speed and uninterrupted access to data increases, the push for higher bandwidth, higher frequency distribution systems with increased coverage is becoming more necessary. The next generation of systems require improved size, weight, and power (SWaP) characteristics as well as wide band performance that make it difficult for current all-electronic solutions to remain the primary method of distribution, particularly with the desire to push into the millimeter wave (mmW) regime. This is where the microwave photonic approach through the means of optical links begins to show major benefits. ☐ In this work, the development of a unique single line in-phase and quatrature-phase (SLIQ) vector modulator is proposed to meet the requirements of a possible photonic link architecture that conforms to the current trends in wireless communication. This device utilizes a single waveguide to achieve the required phase and amplitude modulation needed to transmit signal vectors. This SLIQ design is chosen to overcome the challenges of size and parasitic power consumption inherent to the use of currently available, off the shelf components. The operation of the SLIQ device is derived using the material platform of lithium niobate (LiNbO3), a material used for electro-optic modulation. The device platforms of titanium-diffused waveguides in bulk LiNbO3 and strip-loaded waveguides on thin-film LiNbO3 have their viability and effectiveness explored and both platforms are fabricated in parallel. Fabricated devices are tested and both are shown to exhibit the desirable properties required for a SLIQ modulation. It is found though that silicon nitride strip loaded waveguides on the thin film LiNbO3 platform provide the most desirable operation properties for a SLIQ modulator.