posted on 2023-12-21, 20:40authored byZhuoran Fang, Brian Mills, Rui Chen, Jieying Zhang, Peipeng Xu, Juejun Hu, Arka Majumdar
The programmable photonic integrated
circuit (PIC) is an enabling
technology behind optical interconnects and quantum information processing.
Conventionally, the programmability of PICs is driven by the thermo-optic
effect, free carrier dispersion, or mechanical tuning. These effects
afford either high speed or a large extinction ratio, but all require
constant power or bias to maintain the states, which is undesirable
for programmability with infrequent switching. Recent progress in
programmable PICs based on nonvolatile phase-change materials (PCMs)
offers an attractive solution to a truly “set-and-forget”
switch that requires zero static energy. Here, we report an essential
building block of large-scale programmable PICsa racetrack
resonator with independent control of coupling and phase. We changed
the resonance extinction ratio (ER) without perturbing the resonance
wavelength, leveraging a programmable unit based on a directional
coupler and a low-loss PCM Sb2Se3. The unit
is only 33-μm-long and has an operating bandwidth over 50 nm,
a low insertion loss (∼0.36 dB), high ER (∼15 dB), and
excellent fabrication yield of over 1000 cycles endurance across nine
switches. The work is a crucial step toward future large-scale energy-efficient
programmable PICs.