Published papers

We demonstrate a soliton microcomb-based photonic convolution with direct 300 GHz wireless output. By encoding kernel weights onto comb lines and summing them in a uni-traveling-carrier photodiode, we achieve a 23.1% reduction in computational cost. This approach links photonic computation directly to 300 GHz transmission.

We propose and demonstrate a photonic filter operating in the 300 -GHz band utilizing a soliton comb. Through transmission experiments, we show its ability to suppress jamming signals, paving the way for advances in terahertz communication.

Recent experiments have shown that when a microresonator is pumped with coherent optical pulses under appropriate conditions, optical pulses with durations shorter than 50 fs can be generated [1]. These Raman solitons arise from the complex interplay between nonlinearity and dispersion, and their ultrashort duration makes them highly promising for applications that require high temporal resolution. Such solitons require precise control over the repetition rate of the pump pulse train and the round-trip time of the microresonator. However, theoretical analyses suggest that ultrashort Raman optical pulses will also exist under continuous-wave (CW) pumping conditions. We aim to explore the Raman soliton dynamics and the formation conditions using a microtoroid driven by CW.

We introduce a mode-locking mechanism using coupled microcavities near exceptional points in the context of non-Hermitian physics, eliminating the need for traditional saturable absorbers. It offers a compact, efficient solution for generating ultrafast pulses.

This paper investigates the structural characteristics of photonic crystal (PhC) nanocavities and their application in non-linear optics. By leveraging the unique ability of these nanocavities to confine light within tiny volumes, the study explores their capacity to enhance non-linear optical effects such as frequency conversion and optical switching. Key design strategies, including defect engineering and cavity resonance optimization, are discussed to illustrate how these structures amplify light-matter interactions. The paper also discusses practical applications as optical devices namely as optical modulator and photoreceiver. Finally, all-silicon transmission link has also been demonstrated. We successfully achieved 0.1 Gb/s all-silicon scheme transmission link at 5 m distance with ~ 10 μW.

We show numerically that a pulse with a peak power of ~200W is formed in the Stokes region in a silica microresonator when careful dispersion tailoring is performed.

We show numerically that a pulse with a peak power of ~200W is formed in the Stokes region in a silica microresonator when careful dispersion tailoring is performed.

We show numerically that a pulse with a peak power of ~200W is formed in the Stokes region in a silica microresonator when careful dispersion tailoring is performed.

We show numerically that a pulse with a peak power of ~200W is formed in the Stokes region in a silica microresonator when careful dispersion tailoring is performed.

We show numerically that a pulse with a peak power of ~200W is formed in the Stokes region in a silica microresonator when careful dispersion tailoring is performed.

We show numerically that a pulse with a peak power of ~200W is formed in the Stokes region in a silica microresonator when careful dispersion tailoring is performed.

We show numerically that a pulse with a peak power of ~200W is formed in the Stokes region in a silica microresonator when careful dispersion tailoring is performed.

We show numerically that a pulse with a peak power of ~200W is formed in the Stokes region in a silica microresonator when careful dispersion tailoring is performed.

AMTIR-1 chalcogenide glass has shown its potential for use in thermal imaging systems owing to its low refractive index, thermal resistance, and high transparency across the infrared wavelength regime. Here, we report a millimeter-scale high-Q whispering gallery mode microresonator made of AMTIR-1. The recorded Q-factor has reached 1.2×107 at 1550 nm, which is almost two orders of magnitude higher than previously reported values. We characterize the thermal properties, where low thermal conductivity plays an important role in thermal resonance tuning. We further show that AMTIR-1 resonators support anomalous dispersion as well as a low absorption coefficient near the 7 µm wavelength band, thus offering the possibility of providing suitable platforms for mid-infrared, long-wave infrared nonlinear optics, including microresonator frequency comb generation.

This study explores sol-gel methods for fabricating erbium-doped silica microtoroid resonators, addressing the limitations of conventional doping techniques and enhancing device scalability. We develop a reproducible sol-gel process that yields defect-free films for photonic applications and detail common defects and troubleshooting strategies. Two fabrication methods are compared: traditional film deposition on substrates and the direct coating of prefabricated resonators. The latter enables the fabrication of larger resonator diameters (up to 450 pm) without buckling while achieving a high-g factor and a low lasing threshold of 350 pW. These erbium-doped resonators exhibit multi-mode laser oscillations at 1550 nm, revealing the sol-gel method’s potential for realizing scalable, gain-doped photonic devices.

We performed optical convolution operations using a soliton comb and reduced the computational complexity by 23.1% compared to the electronic digital computer. We successfully modulated and transmitted by radio waves at 300-GHz.

We present a 300 GHz photonic filter based on a soliton microcomb, addressing the increasing demand for high-frequency, low-phase-noise signals in THz-band wireless communications. Utilizing a uni-traveling-carrier photodiode (UTC-PD), our configuration enables the generation of 300 GHz waves through beat signals from adjacent longitudinal modes of the microcomb. By combining the UTC-PD with a photonic filter approach, we demonstrate that RF photonic filters with high suppression ratios are achieved in the 300 GHz band. Additionally, by mitigating the effects of higher-order dispersion, we achieve a stopband rejection exceeding 30 dB. These results underscore the potential of our photonic filter for advanced THz applications and provide a promising pathway for low-noise, high-bandwidth wireless communication systems.

Through numerical analyses, we demonstrate that robust mode-locking can be achieved without the use of saturable absorbers by either exploiting stimulated Raman scattering in dispersion-engineered microresonators or by operating near exceptional points in PT-symmetric coupled cavities.

We successfully reconstruct the spectrum of a multi-wavelength input by using the inverse matrix method for data obtained with a random chirped photonic crystal waveguide.

As the limits of computational power continue to increase, concern has arisen regarding insufficient security along with a demand for improvements in encryption methods for data transmission, which might be achieved by chaos synchronization [1, 2]. Using modified Lugiato-Levefer equations (LLEs), we numerically explore two cascaded microresonator frequency combs [3]. To obtain a chaotic state, both cavities are pumped by continuous-wave lasers until modulation instability (MI) combs are generated. By injecting the output of the first resonator into the second resonator, both chaotic fields in the cavities are synchronized. In this work, we investigate to what extent the chaos is synchronized and how this phenomenon may be implemented in existing data transmission systems over a chaotic channel to enable secure communication.