Photonic generation of millimeter-wave signal based on semiconductor hybrid lasers with feedback from an external waveguide resonator circuit

Abstract In this paper, a photonic millimeter-wave (mm-wave) generation system based on heterogeneous integration is proposed to address the issues that conventional schemes are limited by the linear region of active devices and struggle to realize on-chip integration of high-frequency mm-waves. This system adopts a passive micro-ring resonator (MRR) to construct a feedback external cavity structure. The structure performs spectral filtering and linewidth compression on the broadband light emitted by a reflective semiconductor optical amplifier, thus generating a multi-wavelength narrow-linewidth laser with equal frequency spacing. The optical beating effect of a high-speed photodetector is then utilized to convert the laser signal into an mm-wave signal. Simulation results demonstrate that the proposed system successfully generates a high-frequency mm-wave signal at 300 GHz, with an output power of −24.16 dBm and a linewidth as low as 450 kHz. In comparison with traditional schemes based on active nonlinear devices, including external modulation, dual-wavelength beating and optoelectronic oscillator, the passive MRR is free from the inherent limitation of linear operating region, enabling mm-wave generation over a broader frequency range and at a higher operating frequency, which provides technical support for application scenarios such as radar, imaging and sensing. In addition, this system achieves silicon substrate integration of different material systems based on heterogeneous integration technology. By integrating the inherent advantages of various materials, the resulting hybrid silicon fully on-chip integrated design compatible with the CMOS process offers crucial technical support for the integration and miniaturization of microwave photonic systems.