We propose and demonstrate an integrated microwave photonic sideband selector based on the thin-film lithium niobate (TFLN) platform by integrating an electro-optic Mach–Zehnder modulator (MZM) and a thermo-optic tunable flat-top microring filter. The sideband selector has two functions: electro-optic modulation of wideband RF signal and sideband selection. The microwave photonic sideband selector supports processing RF signals up to 40 GHz, with undesired sidebands effectively suppressed by more than 25 dB. The demonstrated device shows great potential for TFLN integrated technology in microwave photonic applications, such as mixing and frequency measurement.

Self-referenced dissipative Kerr solitons (DKSs) based on optical microresonators offer prominent characteristics allowing for various applications from precision measurement to astronomical spectrometer calibration. To date, direct octave-spanning DKS generation has been achieved only in ultrahigh-Q silicon nitride microresonators under optimized laser tuning speed or bi-directional tuning. Here we propose a simple method to easily access the octave-spanning DKS in an aluminum nitride (AlN) microresonator. In the design, two modes that belong to different families but with the same polarization are nearly degenerate and act as a pump and an auxiliary resonance, respectively. The presence of the auxiliary resonance can balance the thermal dragging effect, crucially simplifying the DKS generation with a single pump and leading to an enhanced soliton access window. We experimentally demonstrate the long-lived DKS operation with a record single-soliton step (10.4 GHz or 83 pm) and an octave-spanning bandwidth (1100–2300 nm) through adiabatic pump tuning. Our scheme also allows for direct creation of the DKS state with high probability and without elaborate wavelength or power schemes being required to stabilize the soliton behavior.

We propose a design of single-mode orbital angular momentum (OAM) beam laser with high direct-modulation bandwidth. It is a microcylinder/microring cavity interacted with two types of second-order gratings: the complex top grating containing the real part and the imaginary part modulations and the side grating. The side grating etched on the periphery of the microcylinder/microring cavity can select a whispering gallery mode with a specific azimuthal mode number, while the complex top grating can scatter the lasing mode with travelling-wave pattern vertically. With the cooperation of the gratings, the laser works with a single mode and emits radially polarized OAM beams. With an asymmetrical pad metal on the top of the cavity, the OAM on-chip laser can firstly be directly modulated with electrical pumping. Due to the small active volume, the laser with low threshold current is predicted to have a high direct modulation bandwidth about 29 GHz with the bias current of ten times the threshold from the simulation. The semiconductor OAM laser can be rather easily realized at different wavelengths such as the O band, C band, and L band.

A thermally tuned multi-channel interference widely tunable semiconductor laser is designed and demonstrated, for the first time to our knowledge, that realizes a tuning range of more than 45 nm, side-mode suppression ratios up to 56 dB, and Lorentzian linewidth below 160 kHz. AlGaInAs multiple quantum wells (MQWs) were used to reduce linewidth, which have a lower linewidth enhancement factor compared with InGaAsP MQWs. To decrease the power consumption of micro-heaters, air gaps were fabricated below the arm phase sections. For a 75 μm long suspended thermal tuning waveguide, about 6.3 mW micro-heater tuning power is needed for a 2π round-trip phase change. Total micro-heater tuning power required is less than 50 mW across the whole tuning range, which is lower than that of the reported thermally tuned tunable semiconductor lasers.