Ultrahigh Endurance and Extinction Ratio in Programmable Silicon Photonics Based on a Phase Change Material with ITO Heater
Jian Xia,
Zixuan Wang,
Rui Yang
et al.
Abstract:Phase‐change‐materials (PCMs) integrated photonics have attracted extensive attention in the field of optical neural networks. However, present PCMs‐integrated photonics are still far from meeting the requirements in real‐world applications due to its unsatisfactory endurance (<3000 cycles) and extinction ratio (ER<20 dB). Here, ultrahigh endurance (>30 000 cycles) and large ER (≥50 dB) are achieved in the photonic device by introducing a trench structure to the indium tin oxide (ITO) heater and utili… Show more
“…Recent years has indeed witnessed significant advancements in PCMbased programmable PICs, controlled by short laser or electrical pulses for applications such as optical memories 31,32 , programmable optical switches 20,21,23,24,[33][34][35][36] , low-power in-memory computing 10,14,37,38 and optical trimming 22,24 . Compared to the optical actuation scheme 10,14,31,33,39 , the electrically controlled methods 20,21,23,24,26,35,36 eliminate the requirements for sophisticated and bulky pulsed laser setups. Therefore, they are more promising for a faster and more accessible real-time control, enabling true integration of the entire optical systems on a chip.…”
mentioning
confidence: 99%
“…S11) shows some black areas at the edge of waveguides after the cyclability test, which could be a result of Sb 2 S 3 ablation or thermal reflowing. Several strategies can be used to further improve the cyclability, such as developing more endurable PCMs 35 , engineering the thickness and material of the encapsulation layer 48 , patterning the PCMs into subwavelength nanostructures 49 , and engineering the microheaters and pulse conditions to provide a uniform temperature distribution 44 .…”
Programmable photonic integrated circuits (PICs) consisting of reconfigurable on-chip optical components have been creating new paradigms in various applications, such as integrated spectroscopy, multi-purpose microwave photonics, and optical information processing. Among many reconfiguration mechanisms, non-volatile chalcogenide phase-change materials (PCMs) exhibit a promising approach to the future very-large-scale programmable PICs, thanks to their zero static power and large optical index modulation, leading to extremely low energy consumption and ultra-compact footprints. However, the scalability of the current PCM-based programmable PICs is still limited since they are not directly off-the-shelf in commercial photonic foundries now. Here, we demonstrate a scalable platform harnessing the mature and reliable 300 mm silicon photonic fab, assisted by an in-house wide-bandgap PCM (Sb2S3) integration process. We show various non-volatile programmable devices, including micro-ring resonators, Mach-Zehnder interferometers and asymmetric directional couplers, with low loss (~0.0044 dB/µm), large phase shift (~0.012 π/µm) and high endurance (>5000 switching events with little performance degradation). Moreover, we showcase this platform’s capability of handling relatively complex structures such as multiple PIN diode heaters in devices, each independently controlling an Sb2S3 segment. By reliably setting the Sb2S3 segments to fully amorphous or crystalline state, we achieved deterministic multilevel operation. An asymmetric directional coupler with two unequal-length Sb2S3 segments showed the capability of four-level switching, beyond cross-and-bar binary states. We further showed unbalanced Mach-Zehnder interferometers with equal-length and unequal-length Sb2S3 segments, exhibiting reversible switching and a maximum of 5 ($$N+1,N=4$$
N
+
1
,
N
=
4
) and 8 ($${2}^{N},N=3$$
2
N
,
N
=
3
) equally spaced operation levels, respectively. This work lays the foundation for future programmable very-large-scale PICs with deterministic programmability.
“…Recent years has indeed witnessed significant advancements in PCMbased programmable PICs, controlled by short laser or electrical pulses for applications such as optical memories 31,32 , programmable optical switches 20,21,23,24,[33][34][35][36] , low-power in-memory computing 10,14,37,38 and optical trimming 22,24 . Compared to the optical actuation scheme 10,14,31,33,39 , the electrically controlled methods 20,21,23,24,26,35,36 eliminate the requirements for sophisticated and bulky pulsed laser setups. Therefore, they are more promising for a faster and more accessible real-time control, enabling true integration of the entire optical systems on a chip.…”
mentioning
confidence: 99%
“…S11) shows some black areas at the edge of waveguides after the cyclability test, which could be a result of Sb 2 S 3 ablation or thermal reflowing. Several strategies can be used to further improve the cyclability, such as developing more endurable PCMs 35 , engineering the thickness and material of the encapsulation layer 48 , patterning the PCMs into subwavelength nanostructures 49 , and engineering the microheaters and pulse conditions to provide a uniform temperature distribution 44 .…”
Programmable photonic integrated circuits (PICs) consisting of reconfigurable on-chip optical components have been creating new paradigms in various applications, such as integrated spectroscopy, multi-purpose microwave photonics, and optical information processing. Among many reconfiguration mechanisms, non-volatile chalcogenide phase-change materials (PCMs) exhibit a promising approach to the future very-large-scale programmable PICs, thanks to their zero static power and large optical index modulation, leading to extremely low energy consumption and ultra-compact footprints. However, the scalability of the current PCM-based programmable PICs is still limited since they are not directly off-the-shelf in commercial photonic foundries now. Here, we demonstrate a scalable platform harnessing the mature and reliable 300 mm silicon photonic fab, assisted by an in-house wide-bandgap PCM (Sb2S3) integration process. We show various non-volatile programmable devices, including micro-ring resonators, Mach-Zehnder interferometers and asymmetric directional couplers, with low loss (~0.0044 dB/µm), large phase shift (~0.012 π/µm) and high endurance (>5000 switching events with little performance degradation). Moreover, we showcase this platform’s capability of handling relatively complex structures such as multiple PIN diode heaters in devices, each independently controlling an Sb2S3 segment. By reliably setting the Sb2S3 segments to fully amorphous or crystalline state, we achieved deterministic multilevel operation. An asymmetric directional coupler with two unequal-length Sb2S3 segments showed the capability of four-level switching, beyond cross-and-bar binary states. We further showed unbalanced Mach-Zehnder interferometers with equal-length and unequal-length Sb2S3 segments, exhibiting reversible switching and a maximum of 5 ($$N+1,N=4$$
N
+
1
,
N
=
4
) and 8 ($${2}^{N},N=3$$
2
N
,
N
=
3
) equally spaced operation levels, respectively. This work lays the foundation for future programmable very-large-scale PICs with deterministic programmability.
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