3.5-mm-square InGaAs p-i-n photodiodes and their application to optical-axis arrangement between 1.3-μm laser diodes and a SMF

InGaAs p-i-n photodiodes (PD) with 3.5-mm×3.5-mm-large photosensitive area have been fabricated using chlorine-vapor-phase-epitaxial (C-VPE) growth. They showed high responsivity of 0.95 A/W (λ=1.3 μm) and 1.2 A/W (λ=1.55 μm) and good homogeneity in the whole area. Long-term reliability was confirmed through high-temperature aging tests at 150°C up to 5200 hours. A PD with two pairs of parallel electrodes (PE-PD) was applied to optical-axis arrangement between 1.3-μm laser diodes (LD´s) and a single mode fibre (SMF). The beam position of a LD was detected in error within ±20 μm using PE-PD prior to coupling of a LD beam into a SMF. Total inspection time was reduced to one third the original time