Presentation Title

Design of Integrated Phase Shifter for Breakthrough Starshot

Faculty Mentor

John E. Bowers, Ph.D.

Start Date

17-11-2018 8:30 AM

End Date

17-11-2018 10:30 AM

Location

HARBESON 41

Session

POSTER 1

Type of Presentation

Poster

Subject Area

engineering_computer_science

Abstract

Breakthrough Starshot aims to complete interstellar flight in a given human lifespan by using laser radiation pressure to propel nano-crafts at one-fifth of the speed of light. The laser beam can be effectively focused on the nano-craft (the prescribed target) through an optical phased array (OPA) that consists of an array of emitters. To maximize the power in the focal point and steer the beam, the phase of the light injected in each emitter is controlled by an array of integrated phase shifters. In this work, we designed and optimized a thermally tunable phase shifter made of AlxGa1-xAs that works at wavelength of 1060 nm. The temperature of the waveguide is adjusted through the Joule effect by injecting a current in a 100 nm thick titanium-nitride strip on top of the structure. To operate in single-mode, we choose the width, the height, and the slab thickness of the waveguide equal to 2.0 �m, 2.1 �m, and 1.2 �m respectively. The thickness of the top cladding (Al0.25Ga0.75As) is optimized to minimize the propagation loss induced by the metal and maximize the thermal heating. The phase change is linked to the temperature variation through the thermo-optic coefficient of the GaAs. We demonstrated that a minimum length of 21.0 �m is required for a 2π shift with a negligible insertion loss for the TE polarized optical mode.

Summary of research results to be presented

To operate in single-mode of the AlxGa1-xAs waveguide, the width, the height, and the slab thickness of the waveguide is equal to 2.0 �m, 2.1 �m, and 1.2 �m respectively. A minimum length of 21.0 �m is required for a 2π shift with negligible insertion loss for the TE polarized optical mode for optimized thermal phase tuning.

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Nov 17th, 8:30 AM Nov 17th, 10:30 AM

Design of Integrated Phase Shifter for Breakthrough Starshot

HARBESON 41

Breakthrough Starshot aims to complete interstellar flight in a given human lifespan by using laser radiation pressure to propel nano-crafts at one-fifth of the speed of light. The laser beam can be effectively focused on the nano-craft (the prescribed target) through an optical phased array (OPA) that consists of an array of emitters. To maximize the power in the focal point and steer the beam, the phase of the light injected in each emitter is controlled by an array of integrated phase shifters. In this work, we designed and optimized a thermally tunable phase shifter made of AlxGa1-xAs that works at wavelength of 1060 nm. The temperature of the waveguide is adjusted through the Joule effect by injecting a current in a 100 nm thick titanium-nitride strip on top of the structure. To operate in single-mode, we choose the width, the height, and the slab thickness of the waveguide equal to 2.0 �m, 2.1 �m, and 1.2 �m respectively. The thickness of the top cladding (Al0.25Ga0.75As) is optimized to minimize the propagation loss induced by the metal and maximize the thermal heating. The phase change is linked to the temperature variation through the thermo-optic coefficient of the GaAs. We demonstrated that a minimum length of 21.0 �m is required for a 2π shift with a negligible insertion loss for the TE polarized optical mode.