| 摘要 |
<p>The object of the invention is to provide an optical filtering system which can utilize wide angle optics and still maintain a very narrow pass band. A filtering system (100) is disclosed for receiving and bandpass filtering free space optical signals. The filtering system (100) includes a compound parabolic concentrator (110) with a small aperture for accepting the free space optical signals (115) and a larger aperture whereby the optical signal (115) exits. The compound parabolic concentrator (110) has a reflective coating on the inner surface to reflect incident optical signals (115) to produce a substantially collimated signal beam. The collimated signal is further passed through a narrow, bandpass filter (140) before detection by a photodetector device (150). In an alternative embodiment, a compound hyperbolic concentrator (310) is utilized to reflect the incident optical signals and produce a substantially collimated signal beam.</p> |
