摘要 |
<p>An optical filter tuning apparatus and filtering method which uses an optical filter (8) that reflects light of a predetermined wavelength which is dependent on the position of incidence (16) of the light on the filter (8), and a retroreflector (32) moveable with respect to the filter (8) and which reflects light from an optical source (4) to the position of incidence (16) and reflects light of the predetermined wavelength from the filter (8) to an optical receiver (6).</p> |