Active optical measurement device with weak signal amplification

摘要

The device has two light beams with different wave lengths, where one of the beam illuminates a reference medium (60) sending a light wave (Sr) to an optical coupler (70) which receives the other beam. The coupler provides an output wave (Or) having the latter beam and the wave (Sr) to an optical amplification unit (80), where the unit provides an amplified output wave (Ora).