| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain an optical fiber microwave transmitter which can deal with a large variation of optical path length, and can compensate for the variation of optical path length by compensating for the phase variation. <P>SOLUTION: In an optical fiber microwave transmitter, the frequency of one branch light of laser light branched into two is shifted by an optical frequency shifter 10 according to a first microwave signal for modulation thus producing frequency shifted light, which is then multiplexed with the other branch light to produce multiplexed light being transmitted by a transmission optical fiber 5. A part of the multiplexed light transmitted by partial reflection means 6, 21, 22 via the transmission optical fiber is reflected to the transmission optical fiber side as partial reflection light. Phase comparison means 11 and first microwave for modulation generating means 12, 13 convert the partial reflection light into an electric signal thus producing a second microwave signal. According to the phase difference between the second microwave signal and a reference microwave signal, frequency of the first microwave signal for modulation to the optical frequency shifter is controlled and then the first microwave signal for modulation is output. <P>COPYRIGHT: (C)2012,JPO&INPIT |
