Abstract
Microwave Photonic links are used for the transmission of microwave signals over optical fiber. The advantages of microwave photonic links in comparison to conventional microwave links include lower loss, improved flexibility, and immunity to electromagnetic interference. Microwave photonic links consist of an optical source (laser), a modulator, a detector, and optical fiber. Requirements for modern electronic warfare applications include the acceptance of high optical power (250mW or higher), low noise figure (~3dB), efficiency (Vπ<5V) and bandwidth (20GHz or higher) for C-band (1550nm wavelength) operation. Thiswork outlines the theory, design and nanofabrication process for an electro-optic modulator meeting current standards by modern microwave and electronic warfare systems for efficiency and spurious-free dynamic range in an intensity-modulated direct-detection link with preamplification using a low noise amplifier. The material platform for the modulator is the III-V semiconductor ternary compound of gallium arsenide (GaAs) and aluminum gallium arsenide (AlGaAs). This device uses an intensity modulation scheme. Design efforts include epitaxial layer design, optical waveguide design, and microwave electrode design. Nanofabrication processes were tested at University of Massachusetts Lowell’s Nanofabrication Facilities and the GaAs/AlGaAs wafer was epitaxially grown in Massachusetts.