UCLA researchers have developed a monolithically integrated terahertz optoelectronic platform that enables both THz generation and detection on a single chip. This approach offers a compact, scalable solution for applications in wireless communication, imaging, and spectroscopy, overcoming long-standing barriers in THz system complexity and integration.
BACKGROUND: Terahertz (THz) technologies hold enormous promise for next-generation applications in wireless communications, security imaging, and chemical detection. These frequencies offer a unique combination of spatial resolution, spectral specificity, and non-ionizing penetration, making them attractive across industries. Yet, despite decades of academic interest and compelling use cases, THz systems have struggled to transition into real-world deployment. Most current solutions rely on bulky external lasers, photoconductive antennas, and free-space optics—making them costly, fragile, and difficult to scale or integrate. Existing miniaturization efforts have largely fallen short, constrained by the difficulty of combining THz generation and detection in a single platform without performance trade-offs. A solution that can address these challenges—through true monolithic integration—would dramatically reduce system complexity and cost, opening the door to widespread adoption across sectors ranging from telecom and defense to biomedical imaging and process control.
INNOVATION: This invention achieves integration of THz generation and detection by combining a THz photomixer, a semiconductor optical amplifier, and supporting photonic structures on a single quantum well PIN diode platform. The system operates through optical heterodyning and rectification, allowing THz emission and detection using standard telecom-band lasers. Tapered waveguides are used to resolve mode mismatch across components, optimizing coupling efficiency. The result is a compact chip that operates across a wide frequency band (140–500 GHz), demonstrating record optical-to-THz conversion efficiency and ultralow noise equivalent power (NEP). Importantly, the architecture is compatible with III–V photonic foundry processes, supporting future integration with lasers, phase modulators, and passive waveguides for a fully self-contained THz system.
POTENTIAL APPLICATIONS:
- High-resolution THz imaging for medical diagnostics and security screening
- On-chip THz spectroscopy for chemical and biological sensing
- Wireless communications operating at THz and sub-THz frequencies
- Photonic integrated circuits (PICs) with embedded THz functionality
ADVANTAGES:
- Combines THz generation and detection on a single chip
- Broad frequency operation (140–500 GHz) with high signal fidelity
- Foundry-compatible and scalable using III–V semiconductor processes
- Eliminates external lasers, optical components, and antenna alignment
- Enables wafer-scale THz manufacturing and packaging
DEVELOPMENT-TO-DATE: Prototype devices have been fabricated and characterized, demonstrating THz output power of –10 to –35 dBm and detection sensitivity down to 2.3 pW/Hz. Benchmarking studies validate performance across the 140–500 GHz band. The architecture has been designed with manufacturing scalability in mind, and integration with additional active components is feasible through existing photonic foundry workflows.
KEYWORDS: Semiconductor photonics, THz devices, Integrated photonics, Quantum wells, Chips-Scale Sensing, Wireless Communications, Spectroscopy, Heterodyne Detection