Integrated Photonics and Applications Centre, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia
Xu Han
Armandas Balčytis
Integrated Photonics and Applications Centre, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia
Aditya Dubey
Integrated Photonics and Applications Centre, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia
Andreas Boes
Integrated Photonics and Applications Centre, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia
Thach G. Nguyen
Integrated Photonics and Applications Centre, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia
Guanghui Ren
Integrated Photonics and Applications Centre, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia
Mengxi Tan
Integrated Photonics and Applications Centre, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia
Yonghui Tian
Key Laboratory for Magnetism and Magnetic Materials of MOE, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, Gansu, China
Arnan Mitchell
Integrated Photonics and Applications Centre, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia
High efficiency and a compact footprint are desired properties for electro-optic modulators. In this paper, we propose, theoretically investigate, and experimentally demonstrate a recirculating phase modulator, which increases the modulation efficiency by modulating the optical field several times in a non-resonant waveguide structure. The “recycling” of light is achieved by looping the optical path that exits the phase modulator back and coupling it to a higher order waveguide mode, which then repeats its passage through the phase modulator. By looping the light back twice, we were able to demonstrate a recirculating phase modulator that requires nine times lower power to generate the same modulation index of a single pass phase modulator. This approach to modulation efficiency enhancement is promising for the design of advanced tunable electro-optical frequency comb generators and other electro-optical devices with defined operational frequency bandwidths.
