| 摘要 |
A laser transmitter is disclosed in which the laser combines the outputs of numerous laser diodes using dichroic combination to produce a high power, diffraction limited beam which may be transmitted at minimum beam divergence using the full aperture of the transmitter telescope. The individual diode beams are combined and superimposed in the laser, and are transmitted superimposed in the near and far field of the transmitter telescope. The dichroic combining process is as follows. A collimate beam of a first wavelength is directed at a narrowband or long wave pass filter which is tilted slightly (about 10 degrees). This beam passes through the filter. A beam of a second wavelength is directed toward the exit side of the filter (which acts as a mirror) at such an angle that the second beam is reflected colinear with the first beam and superimposed on it. This process of superimposing the laser beams continues as each laser beam from the laser diodes is added to form a combined laser beam. Before transmission, a sample is extracted from the combined laser beam, and filtered at the discrete wavelengths of the laser diodes to determine if each of the laser diodes needs to be adjusted. When necessary, the laser diodes are thermally adjusted so that their laser beams are at their specific discrete wavelength.
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