Provided is a pressure-sensitive adhesive capable of realizing a pressure-sensitive adhesive layer having satisfactory adhesion performance and a high ink step absorbability. Micro-mirrors are formed in the device layer, and access bores extend through the handle layer and the oxide layer to the micro-mirrors for accommodating optical fibres to the micro-mirrors. A first input of the amplifier circuit is coupled to a node between the current source and the first diode. The cavity walls may contain extra routing metallization to create bypass capacitors to enhance electrical performance.