<p>➀ Researchers developed an on-chip THz multiplexer using inverse design and quantum cascade lasers, operating in the 2.2–3.2 THz range;</p><p>➁ The compact device (200×200 µm) integrates III–V semiconductors and polymer waveguides, achieving three broadband channels with low crosstalk;</p><p>➂ Applications include THz communication and spectroscopy, demonstrating potential for scalable photonic integration beyond telecom wavelengths.</p>