Zhiyong Li

A high-sensitivity and high-stability on-chip temperature sensor based on a silicon-on-insulator (SOI) platform is proposed and experimentally demonstrated in this work. The device employs a ring-assisted asymmetric Mach–Zehnder interferometer (RAMZI), enhancing both temperature sensitivity and measurement stability. Broadband, wavelength-insensitive components, including multimode interference couplers and adiabatic 3 dB splitters, reduce the influence of laser wavelength fluctuations and mitigate interference errors caused by environmental perturbations. The sensor achieves a temperature sensitivity of 108.74 pm/K, corresponding to an approximately 40% improvement over a conventional AMZI with the same footprint. Moreover, a wavelength drift of only 18 pm over 45 min demonstrates excellent stability and robustness. This work provides an effective solution for highly sensitive and stable on-chip temperature sensing in photonic integrated systems.

Electro-optic modulators with large bandwidth and low voltage are crucial for the high-baud-rate digital communication and high-carrier-frequency analog links. Recently, thin-film lithium niobate (TFLN) modulators with sub-1 V voltage and 140 GHz bandwidth have been emerged on the low permittivity substrates, such as quartz. However, on the high permittivity environment, such as silicon substrates, the bandwidth dramatically reduced to below 100 GHz even if the voltage was raised to around 3 V. We break the voltage-bandwidth trade-off limit in TFLN modulators on silicon substrates using low inductance thick metal traveling wave electrodes, which reduce RF phase index and microwave losses while preserving high EO modulation efficiency. We demonstrate a TFLN EO modulator on silicon substrate with 3 dB EO bandwidth $>$ 120 GHz and half-wave voltage $(V_\pi) < $ 2 V. Bandwidth/ $V_\pi$ reach 60, which is significantly larger than traditional TFLN modulators. The proposed thin-film lithium niobate modulators offers a practical solution for the hybrid integration of silicon and lithium niobate.

High-speed silicon traveling-wave Mach-Zehnder modulators (MZMs) modulators are key components to support optical fiber communication. However, one major challenge with all-silicon MZMs is to achieve efficient high-speed electro-optic (EO) modulation. The reported 3 dB bandwidth of silicon MZMs are generally below 70 GHz, with half-wave voltage (Vπ) around 5 V or larger, which can not support future 200 Gbaud data transmission. Here we break the voltage–bandwidth trade-off limit in silicon MZMs by replacing the doped silicon slab with CMOS compatible transparent electrodes. Benefit from the measured high conductivity, low extinction coefficient, and low refractive index of indium tin oxide (ITO) materials, the microwave dielectric loss of the traveling wave electrode can be greatly reduced. The bandwidth would potentially increase from 40 GHz to 168 GHz, while Vπ and optical insertion loss remains almost unchanged. According to Si/ITO interface contact states, three operating mode were found, corresponding to Si/ITO ohmic contact, schottky contact and hybrid schottky/ohmic contact, respectively. We comprehensively analysis the Si/ITO interface characteristic, establish a complete high frequency equivalent circuit model. Our proposed transparent electrodes will open a new window for the high-speed silicon photonics platform.

High-speed silicon traveling-wave Mach-Zehnder modulators (MZMs) modulators are key components to support optical fiber communication. However, one major challenge with all-silicon MZMs is to achieve efficient high-speed electro-optic (EO) modulation. The reported 3 dB bandwidth of silicon MZMs are generally below 70 GHz, with half-wave voltage (Vπ) around 5 V or larger, which can not support future 200 Gbaud data transmission. Here we break the voltage–bandwidth trade-off limit in silicon MZMs by replacing the doped silicon slab with CMOS compatible transparent electrodes. Benefit from the measured high conductivity, low extinction coefficient, and low refractive index of indium tin oxide (ITO) materials, the microwave dielectric loss of the traveling wave electrode can be greatly reduced. The bandwidth would potentially increase from 40 GHz to 168 GHz, while Vπ and optical insertion loss remains almost unchanged. According to Si/ITO interface contact states, three operating mode were found, corresponding to Si/ITO ohmic contact, schottky contact and hybrid schottky/ohmic contact, respectively. We comprehensively analysis the Si/ITO interface characteristic, establish a complete high frequency equivalent circuit model. Our proposed transparent electrodes will open a new window for the high-speed silicon photonics platform.

High-speed silicon traveling-wave Mach-Zehnder modulators (MZMs) modulators are key components to support optical fiber communication. However, one major challenge with all-silicon MZMs is to achieve efficient high-speed electro-optic (EO) modulation. The reported 3 dB bandwidth of silicon MZMs are generally below 70 GHz, with half-wave voltage (Vπ) around 5 V or larger, which can not support future 200 Gbaud data transmission. Here we break the voltage–bandwidth trade-off limit in silicon MZMs by replacing the doped silicon slab with CMOS compatible transparent electrodes. Benefit from the measured high conductivity, low extinction coefficient, and low refractive index of indium tin oxide (ITO) materials, the microwave dielectric loss of the traveling wave electrode can be greatly reduced. The bandwidth would potentially increase from 40 GHz to 168 GHz, while Vπ and optical insertion loss remains almost unchanged. According to Si/ITO interface contact states, three operating mode were found, corresponding to Si/ITO ohmic contact, schottky contact and hybrid schottky/ohmic contact, respectively. We comprehensively analysis the Si/ITO interface characteristic, establish a complete high frequency equivalent circuit model. Our proposed transparent electrodes will open a new window for the high-speed silicon photonics platform.

High-speed silicon traveling-wave Mach-Zehnder modulators (MZMs) modulators are key components to support optical fiber communication. However, one major challenge with all-silicon MZMs is to achieve efficient high-speed electro-optic (EO) modulation. The reported 3 dB bandwidth of silicon MZMs are generally below 70 GHz, with half-wave voltage (Vπ) around 5 V or larger, which can not support future 200 Gbaud data transmission. Here we break the voltage–bandwidth trade-off limit in silicon MZMs by replacing the doped silicon slab with CMOS compatible transparent electrodes. Benefit from the measured high conductivity, low extinction coefficient, and low refractive index of indium tin oxide (ITO) materials, the microwave dielectric loss of the traveling wave electrode can be greatly reduced. The bandwidth would potentially increase from 40 GHz to 168 GHz, while Vπ and optical insertion loss remains almost unchanged. According to Si/ITO interface contact states, three operating mode were found, corresponding to Si/ITO ohmic contact, schottky contact and hybrid schottky/ohmic contact, respectively. We comprehensively analysis the Si/ITO interface characteristic, establish a complete high frequency equivalent circuit model. Our proposed transparent electrodes will open a new window for the high-speed silicon photonics platform.

We propose and demonstrate a novel on-chip optical sampling pulse interleaver based on time mode interleaving. The designed pulse interleaver was fabricated on a 220 nm silicon-on-insulator (SOI) platform, utilizing only one S-shaped delay waveguide. Interleaving is achieved by the relative time delay between different optical modes in the waveguide, eliminating the need for any active tuning. The total length of the delay waveguide is 5620.5 µm, which is reduced by a factor of 46.3% compared with previously reported time-wavelength interleaver schemes. The experimental results indicate that the device can convert an optical pulse into a 40 GHz pulse sequence composed of four pulses with a root mean square (RMS) timing error of 0.9 ps, making it well suited for generating high-frequency sampling pulses for optical analog-to-digital converters.

In this paper, we demonstrated a silicon forward-biased positive intrinsic negative (PIN) Mach-Zehnder modulator (MZM), which has two operating states of high efficiency and high speed. The two operating states are switched by changing the position where the electric signal is loaded. The modulator incorporates a PIN phase shifter integrated with the passive resistance and capacitance (RC) equalizer (PIN-RC), which expands the electro-optic (E-O) bandwidth by equalizing it with modulation efficiency. The fabricated modulator exhibited a low insertion loss of 1.29 dB in two operating states, and a compact design with a phase shifter length of 500 μm. The modulation efficiencies are 0.0088 V·cm and 1.43 V·cm, and the corresponding 3 dB E-O bandwidths are 200 MHz and 7 GHz, respectively. The high-speed modulation performance of the modulator was confirmed by non-return-to-zero (NRZ) modulation with a data rate of 15 Gbps without any pre-emphasis or post-processing. The presented modulator has great potential in optical computing, high-speed data transmission, and high-performance optical switch arrays.

In this paper, we demonstrated a silicon forward-biased positive intrinsic negative (PIN) Mach-Zehnder modulator (MZM), which has two operating states of high efficiency and high speed. The two operating states are switched by changing the position where the electric signal is loaded. The modulator incorporates a PIN phase shifter integrated with the passive resistance and capacitance (RC) equalizer (PIN-RC), which expands the electro-optic (E-O) bandwidth by equalizing it with modulation efficiency. The fabricated modulator exhibited a low insertion loss of 1.29 dB in two operating states, and a compact design with a phase shifter length of 500 μm. The modulation efficiencies are 0.0088 V·cm and 1.43 V·cm, and the corresponding 3 dB E-O bandwidths are 200 MHz and 7 GHz, respectively. The high-speed modulation performance of the modulator was confirmed by non-return-to-zero (NRZ) modulation with a data rate of 15 Gbps without any pre-emphasis or post-processing. The presented modulator has great potential in optical computing, high-speed data transmission, and high-performance optical switch arrays.