In this paper, we report the first experimental demonstration of the multi-channel interference (MCI) widely tunable semiconductor laser. Mode selection of the MCI laser is achieved by the constructive interference of eight arms with unequal length difference. Compared with conventional widely tunable semiconductor lasers based on distributed Bragg reflectors, fabrication of the MCI laser is simpler with large fabrication tolerances. A quasi-continuous tuning range of about 52.3 nm (1538.96 nm – 1591.26 nm) has been demonstrated at a temperature of 23°C with side-mode suppression-ratios greater than 44 dB across the whole tuning range (typically greater than 48 dB).

Gold wire bonding is a critical interconnection technique for integrated circuit, connecting chips to substrates and enabling communication through slender wires. Gold wires are characterized by slenderness, small size, and multi-angle distribution. Meanwhile, manufacturing errors during gold wire bonding further complicate quality inspection. In this paper, we propose a fully automated gold wire bonding quality inspection framework to detect missing and misconnection wires. Given the small diameter of the gold wire (typically around 0.025 mm) and the complexity of the background, capturing high-quality images is crucial for effective quality detection. Therefore, we first design a gold wire image capture system that integrates a high-resolution camera and lens with a high-precision three-axis motion platform. This system can automatically acquire image data for both the product to be inspected and the defect-free template. Subsequently, we introduce a Slenderness Attention Module (SAM) to detect slender wires with arbitrary orientations. We employ an attention mechanism that combines channel and spatial attention, facilitating precise identification from complex background images. We then establish a Wire Quality Evaluation (WQE) model for gold wire bonding quality inspection, which integrates geometric information and data from the manufacturing process. The experimental results on our gold wire dataset demonstrate the effectiveness of the proposed method in gold wire bonding quality inspection, achieving an average precision (AP) of 85.8%, with precision (P) and recall (R) rates of 88.1% and 88.8%, respectively. The WQE model accurately identifies missing and misconnection wires. It outperforms IoU-based and similarity-based methods by detecting all defects in 16 representative images, including dense and sparse wire arrangements.

In this paper, we report the demonstration of direct-modulation grating-assisted microcylinder surface-emitting lasers (GAMSELs) with low threshold. Two second-order gratings are added onto the side and top of the microcylinder cavity to select a single mode with a radially polarized emission pattern and efficiently emit the mode vertically, respectively. Laser with cavity radius of 6.05 μm is demonstrated with continuous-wave lasing ranging from 1 °C to 50 °C. This radius is approaching the theoretically smallest radius for the microcylinder laser to work at O band. A low threshold of 3.6 mA at 15 °C is obtained for the GAMSEL laser. Single-mode lasing with side-mode suppression-ratio (SMSR) larger than 40 dB is also shown here. GAMSELs with different cavity radii are demonstrated as laser arrays. 3 dB direct-modulation bandwidth of 12 and 14 GHz of GAMSELs with radius of about 8 and 10 μm are obtained, respectively. Besides, effects of the duty cycle of the top and side gratings, scattering losses of the cavity, gain peak of the epitaxial wafer and ion implantation are experimentally investigated.