Optical switching in hybrid VO₂/Si waveguides thermally triggered by lateral microheaters

Abstract

The performance of optical devices relying in vanadium dioxide (VO) technology compatible with the silicon platform depends on the polarization of light and VO properties. In this work, optical switching in hybrid VO/Si waveguides thermally triggered by lateral microheaters is achieved with insertion losses below 1 dB and extinction ratios above 20 dB in a broad bandwidth larger than 30 nm. The optical switching response has been optimized for TE and TM polarizations by using a homogeneous and a granular VO layer, respectively, with a small impact on the electrical power consumption. The stability and reversibility between switching states showing the possibility of bistable performance is also demonstrated.

Toward Nonvolatile Switching in Silicon Photonic Devices

“…Figure a,b shows a waveguide device with a lateral microheater optimized with two metals to reduce the energy consumption. [ 90 ] The optical power variation for TM polarization as a function of the applied electric power is depicted in Figure 12c. The optical loss significantly increases when the VO 2 is switched to the metallic state.…”

“…Reproduced with permission. [ 90 ] Copyright 2018, The Optical Society. d) Hybrid VO 2 /Si waveguide controlled by electrical gating, e) optical image of the fabricated device, and f) measured optical power variation as a function of the applied voltage to the electrodes.…”

“…On the other hand, competitive insertion loss below 0.05 dB µm −1 for TE polarization and 0.3 dB µm −1 for TM polarization has been achieved by engineering the morphology of the VO 2 layer. [90] The dominant mechanism for triggering the VO 2 phase transition has been temperature. The variation of the imaginary part of the refractive index, or extinction coefficient, as a function of temperature and at a wavelength of 1550 nm is depicted in Fig- ure 11c.…”

“…Figure 12. a) Hybrid VO 2 /Si waveguide controlled by a lateral microheater, b) SEM image of the active region,and c) measured optical power variation as a function of the applied electrical power to the heater. Reproduced with permission [90]. Copyright 2018, The Optical Society.…”

Integrated all-optical VO2/Si waveguide switch

“…Thus, its integration in the silicon photonics platform as an active layer seems to be very attractive for providing high-performance photonic devices. Although, some hybrid VO2/Si photonic devices have been demonstrated, these rely on microheaters to trigger the IMT [3,4] or on applying an electrical field [5,6]. Hence, the all-optical feasibility of integrated VO2 devices needs of further investigation.…”