LBTEK detector coupler is a core passive component designed to achieve efficient coupling between fiber output beams and avalanche photodiodes (APDs), minimizing optical signal loss and enhancing the overall signal-to-noise ratio of the detection system. It utilizes a precision optical structure to collimate, focus, and shape the beam, accurately converging the light emitted from the fiber onto the effective photosensitive area of the APD, thereby fully leveraging the detector's high sensitivity. The coupler housing features a light-shielding design to effectively block ambient stray light interference, preventing background optical noise from entering the detection chain and ensuring stable APD detection performance in low-light scenarios. Additionally, LBTEK offers three optional anti-reflection coating ranges: 350 nm–700 nm, 600 nm–1050 nm, and 1050 nm–1700 nm. LBTEK also provides various customization services, including custom dimensions, design wavelengths, and output beam diameters. For specific customization requirements, please contact LBTEK technical support.