The rapid advancement of micro-nano processing technologies has led to the development of highly integrated and reliable photonic chips, which in turn has enabled the development of miniature portable chemical and biological sensors. These sensors are increasingly utilized in applications such as human health monitoring and environmental assessment. Photonic chips incorporate various elements, including light sources, waveguides, gratings, resonant cavities, and detectors. However, the single silicon material cannot fulfill the requirements for all optical components. The indirect bandgap nature of silicon restricts its radiation efficiency, creating an urgent need for highly efficient integrated light-source solutions.

Semiconductor lasers are lightweight, efficient, and reliable, making them well-suited for applications in solid and fiber laser pumping, optical communication, material processing, and molecular spectroscopy. They are ideal light sources for photonic chips. The operating wavelength of a semiconductor laser is closely linked to the energy band structure of the luminescent material. By leveraging various semiconductor material systems and employing energy band engineering, we can achieve a wide range of operating wavelengths across the electromagnetic spectrum . Currently, semiconductor lasers utilizing the direct recombination transition mechanism in material systems such as GaN, GaAs, and InP can achieve coverage of the electromagnetic spectrum from ultraviolet to near-infrared. After the adoption of quantum cascade design, the operating wavelength of lasers is no longer restricted by the material bandgap width, allowing operation in the far-infrared or even terahertz ranges. However, designing lasers that operate in the 2?4 μm wavelength range, corresponding to transition energies of 0.31?0.62 eV, pose significant challenges for both direct recombination and intersubband transitions in the aforementioned material systems. This wavelength range includes the characteristic absorption peaks for several molecules, including CH₄, CO, CO₂, C₂H₆, and HCl, and can be applied to areas such as blood glucose monitoring, making these operating wavelengths essential for photonic sensing chips. The antimonide material system, composed of GaSb, AlSb, InAs, and derived multi-component compound materials, effectively addresses the semiconductor light source gap in the 2?4 μm wavelength band. With comparable lattice constants, this material system features a bandgap in the range of 0.41?1.70 eV and can form type-I, -II, and -III heterojunctions, thus offering high flexibility in energy band design. Constructing type-I and type-II quantum wells enables highly efficient operation within the 2?4 μm band range.

This study focuses on the foundational research related to mid-infrared antimonide light source photonic integrated chips. It begins with a discussion on the epitaxial growth of antimonide high-efficiency gain materials and the mode control of discrete single-mode antimonide devices. Building on this foundation, the study then presents the latest advancements in antimonide heterogeneous integration.

The study first discusses enhancements in radiation efficiency and the expansion of the wavelength range in antimonide lasers grown via GaSb-based epitaxy. Key developmental milestones are outlined in Tables 1 and 2. Significant contributions include the implementation of strained quantum wells, sophisticated waveguide designs that optimize internal losses and light field distribution, the incorporation of high In-component and quinary alloy barriers, and the introduction of type-I quantum well cascade lasers. The study then covers advancements in single-mode antimonide lasers. Addressing the oxidizable nature of the antimonide material system, various strategies, including metal grating laterally coupled distributed feedback (LC-DFB), etched dielectric grating laterally coupled DFB, and socketed ridge-waveguide lasers, are employed to achieve on-chip single-mode antimonide lasers exhibiting a high side-mode suppression ratio (Fig. 12). Finally, the study discusses progress in the silicon-based heterogeneous epitaxy of antimonide lasers. The adoption of techniques such as nucleation layers, miscut substrates, substrate surface reconstruction, and patterned substrates (Fig. 16) helps to solve the problems of lattice mismatch and antiphase domains. In parallel, innovations in in-plane electrodes and etched cavity surface techniques are developed to facilitate the fabrication of high-performance silicon-based antimonide lasers.

Antimonide lasers are important mid-infrared coherent light sources that offer the advantages of compact size, high efficiency, long lifespan, low cost, and straightforward integration. They play a crucial role in various applications such as spectroscopy, precision measurement, space communication, material processing, laser surgery, and laser pumping, thus covering a wide range of industrial, biomedical, and information and communication scenarios, and have scientific research and economic value. The progress achieved in power enhancement, wavelength expansion, longitudinal mode management, and heteroepitaxial integration of antimonide type-I quantum well lasers is promising. It is anticipated that miniaturized practical devices using high-performance antimonide mid-infrared light sources and silicon-based photonics will be realized in the near future.