公开(公告)号：US06512627B1

公开(公告)日：2003-01-28

申请号：US09424967

申请日：1999-11-30

Applicant: Byoung Yoon Kim ,  Wang Joo Lee ,  Bong Kyu Kim

Inventor： Byoung Yoon Kim ,  Wang Joo Lee ,  Bong Kyu Kim

IPC: G02F1365

CPC classification number: G02B6/02071 ,  G01B9/02003 ,  G01B2290/70 ,  G01J9/00 ,  G02B6/105 ,  G02B6/14 ,  G02B6/29353 ,  G02B6/29397 ,  G02F1/0134 ,  G02F2/02

Abstract: This invention relates to optical devices such as a fiber-optic frequency shifter and an optical interferometer. This invention also relates to a method of generating optical interference signals to obtain reliable sensor signals independent of polarization fluctuations of the optical waves in the fiber. Fiber-optic interferometers have many advantages such as high sensitivity and convenient way of using even in poor surrounding environments. These interferometer, however, exhibit polarization dependent signal degradation since the polarization of a light wave passing through an optical fiber irregularly changes depending on the birefringence of the fiber. This invention is characterized in that the frequencies of two orthogonal eigen polarizations of a light wave are shifted to different frequency values at one optical path of the interferometer. They produce two beat interference signals after interfering with the light wave passed through the other optical paht of the interferometer. The two beat interference signals have amplitudes varying complementarily. Selecting the larger one from the two beat signals can prevent polarization dependent signal degradation. Moreover, the beat signals from the optical interferometer according to the invention requires simpler signal processing compared to the output of conventional fiber-optic interferometer.

Abstract translation: 本发明涉及诸如光纤移频器和光干涉仪之类的光器件。 本发明还涉及一种产生光学干涉信号以获得独立于光纤中的光波的偏振波动的可靠传感器信号的方法。 光纤干涉仪具有灵敏度高，使用方便，环境恶劣等优点。 然而，这些干涉仪表现出偏振相关的信号劣化，因为通过光纤的光波的偏振根据光纤的双折射不规则地变化。 本发明的特征在于，在干涉仪的一个光路处将光波的两个正交特征偏振的频率偏移到不同的频率值。 在干扰通过干涉仪的另一光束之后的光波干扰后，它们产生两个拍频干扰信号。 两个差拍干扰信号具有互补变化的幅度。 从两个拍频信号中选择较大的一个可以防止偏振相关信号衰减。 此外，与常规光纤干涉仪的输出相比，根据本发明的光干涉仪的拍频信号需要更简单的信号处理。