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As the critical device of microwave photonics and optical communication, the low-loss and high-efficiency optical phase shifter has attracted intense attention in photonic integrated circuits. However, most of their applications are restricted to a particular band. Little is known about the characteristics of broadband. In this paper, an SiN-MoS 2 integrated broadband racetrack phase shifter is demonstrated. The coupling region and the structure of the racetrack resonator are elaborately designed to improve the coupling efficiency at each resonance wavelength. The ionic liquid is introduced to form a capacitor structure. Then, the effective index of the hybrid waveguide can be efficiently tuned by adjusting the bias voltage. We achieve a phase shifter with a tunable range covering all the WDM bands and even up to 1900 nm. The highest phase tuning efficiency is measured to be 72.75 pm/V at 1860 nm, and the corresponding half-wave-voltage-length product is calculated as 0.0608 V·cm.

We demonstrate a low-power, compact micro-ring phase shifter based on hybrid integration with atomically thin two-dimensional layered materials, and experimentally establish a low-loss silicon nitride platform. Using a wet transfer method, a large-area few-layer MoS 2 film is hybrid integrated with a micro-ring phase shifter, leading to a tuning efficiency of 5.8 pm V -1 at a center wavelength of 1545.294 nm and a half-wave-voltage-length product as low as 0.09 V cm. Our device is designed to provide a hybrid-integration-based active phase modulation scheme for integrated optical communication networks with large-cross-section silicon nitride waveguides.

With the magnetron-sputtering deposition method, α phase indium selenide (α-In 2 Se 3 ) was developed into a saturable absorber (SA) with wideband saturable absorption property at 800, 1560, and 1930 nm. After inserting the α-In 2 Se 3 SA into erbium-doped fiber laser (EDFL) and thulium-doped fiber laser (TDFL) systems, we can easily obtain stable soliton pulse trains. The pulse duration/pulse energy/slope efficiency for EDFL and TDFL were 276 fs/2.03 nJ/15.8% and 1.02 ps/7.1 nJ/23.5%, respectively. These results showed that the MSD-grown α-In 2 Se 3 could be regarded as high efficiency material to be applied in ultrafast photonics.

Ultrafast pulse generation was demonstrated in a thulium-doped fiber laser mode-locked by magnetron-sputtering deposited WTe 2 with a modulation depth, a nonsaturable loss, and a saturable intensity of 31%, 34.3%, and 7.6  MW/cm 2 , respectively. Stable soliton pulses could be obtained at a 1915.5 nm central wavelength with a pulse duration of 1.25 ps, an average output power of 39.9 mW, and a signal-to-noise ratio of 95 dB. To the best of our knowledge, this was the first demonstration of WTe 2 -based saturable absorbers in fiber lasers at a 2 μm regime.