Reflective displacement sensors with monolithically integrated VCSELs and RCEPDs

Abstract

Micro-scale, reflective-type optical displacement sensors have been developed by monolithic integration of vertical cavity surface-emitting lasers (VCSELs) and resonant cavity-enhanced photodetectors (RCEPDs). This compact sensor (700 x 700 mu m) consists of an oxide-confined VCSEL that is surrounded by an RCEPD and can measure the linear distance with a measurement range of similar to 10 mm, which is comparable to that of conventional displacement sensors. Fabrication details and sensor performances are discussed.