A Low Power PWM Optical Phased Array Transmitter with 16° Field-of-View and 0.8° Beamwidth

An optical phased array (OPA) transmitter system with a high-swing electrical PWM driver achieving the highest reported grating-lobe-free field-of-view to beamwidth ratio of 16 degrees/0.8 degrees for a two-dimensional aperture is presented. This ratio translates to 400 resolvable spots-which is 30x more numerous than the state-of-the-art. This scalable OPA, with a sparsely populated aperture, overcomes optical routing difficulties in planar photonic processes while maintaining the desired transmitter beam characteristics. To reduce the power consumption, a row-column electrical connection grid for the 144 optical phase shifters decreases the number of electrical drivers from 144 to 37. The PWM driver chip incorporates a breakdown-voltage multiplying architecture to increase the output voltage swing. The 65nm CMOS electronic driver chip and the photonic chip, fabricated through a standard silicon photonics process, occupy 1.7mm(2) and 2.08mm(2) of active area respectively.