Research on Ion Slicing and on-chip amplifier Design based on Nd: YAG Laser Ceramics

Sub-micron solid gain films on insulator represent a promising route towards higher-power on-chip optical amplifiers and lasers. However, achieving precise thickness control, scalable fabrication, and high optical quality remains a significant challenge. The ion-slicing technique, commonly used with laser crystals, offers potential to address these issues. Nevertheless, applying it to fabricate Nd:YAG films on insulator encounters challenges due to thermal mismatch during the required high-temperature annealing step. Under identical high-temperature conditions, Nd:YAG transparent ceramics benefit from their grain boundary-enhanced fracture toughness. This allows grain boundaries to arrest microcrack propagation, thereby preventing fracture induced by thermal stress. we demonstrate an Nd:YAG transparent ceramic film platform on sapphire substrate (NYOS) using the ion-slicing technique. Based on this platform, we propose a Si₃N₄ waveguide amplifier design. This amplifier achieves a peak gain of 25 dB for a waveguide length of 12 cm. We systematically elucidate a dual-channel mechanism for thermal stress release during the peeling of polycrystalline transparent ceramic films. By implementing an optimized step-annealing process, which comprising a 400°C pre-anneal followed by a 900°C anneal, we achieved results where post-anneal grain spalling was less than 1% of the total implanted area, and the film peeling area exceeded 95% of the total implanted area. This process effectively suppresses grain spalling and significantly enhances film peeling. This study demonstrates the advantage of ceramic materials for thermal stress management. It provides key device design and thin-film fabrication strategies crucial for developing silicon-based integrated Nd:YAG ceramic optical amplifiers.