Due to the slowdown of Moore's law, the integrated photonic devices have provided a route to promote the development of large‐scale optical communications with high performance. As one of the essential components of optical routers, an optical switch can fast transmit or block the optical signal. However, most of the integrated optical switches reported to date rely on thermo‐, magneto‐, or electro‐optical effects, which limit applications due to slow response times, large footprint, and complexity fabrication. Here, an integrated nonlinear optical switch designed by the inverse‐design method and fabricated on the SiN platform is introduced. The integrated optical switch is demonstrated with significant intensity‐dependent transmission at 1.5 µm waveband. The polarization‐depended capability is explored by using fundamental polarized lights (transverse electric and transverse magnetic, respectively), which exhibits opposite transmission change trends during the whole power range and opens potential applications such as photonic quantum information processing. In order to address the saturation of Kerr‐nonlinearity in SiN materials at high power, a MoS2/SiN hybrid integrated optical switch is fabricated by uniformly cladding few‐layer MoS2 on the surface of inverse‐designed region. That is demonstrated to enhance the nonlinear optical response of device efficiently and achieve more excellent switching capability at high power.

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 MoS2 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.

Silicon nitride, with ultralow propagation loss and a wide transparency window, offers an exciting platform to explore integrated photonic devices for various emerging applications. It is appealing to combine the intrinsic optical properties of two-dimensional layered materials with high-quality optical waveguides and resonators to achieve functional devices in a single chip. Here we demonstrate a micro-ring resonator-based phase modulator integrated with few-layer MoS 2 . The ionic liquid is employed directly on the surface of MoS 2 to form a capacitor configuration. The effective index of the composite MoS 2 – SiN waveguide can be modulated via adjusting bias voltages to achieve different charged doping induced electro-refractive responses in MoS 2 film. The maximum effective index modulation of the composite MoS 2 – SiN waveguide can be achieved to 0.45 × 10 − 3 . The phase tuning efficiency is measured to be 29.42 pm/V, corresponding to a V π L of 0.69 V·cm. Since the micro-ring resonator is designed near the critical coupling regime, the coupling condition between the bus waveguide and micro-ring resonator can also be engineered from under-coupling to over-coupling regime during the charged doping process. That can be involved as a degree of freedom for the coupling tailoring. The ability to modulate the effective index with two-dimensional materials and the robust nature of the heterostructure integrated phase modulator could be useful for engineering reliable ultra-compact and low-power-consumption integrated photonic devices.

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-MoS2 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.

Gradient-based optimization combined with the adjoint method has been demonstrated to be an efficient way to design a nano-structure with a vast number of degrees of freedom. However, most inverse-designed photonic devices are applied as linear photonic devices. Here, we demonstrate the nonlinear optical response in inverse-designed integrated splitters fabricated on a SiN platform. The splitting ratio is tunable under different incident powers. The thermo-optical effect can be used as an effective approach for adjusting the nonlinear optical response threshold and modulation depth of the device. These promising results indicate the great potential of inverse-designed photonic devices in nonlinear optics and optical communications.