| 摘要 |
An optical frequency discriminator having enhanced linearity is provided, which discriminator may be utilized in FM communications systems or in other applications. The discriminator has two interferometers with the optical path length difference for the first interferometer being DELTA L and for the second interferometer being m DELTA L where m>1. The optical FM signal is applied in parallel to both optical interferometers with approximately m3 times as much of the signal being applied to the first interferometer as to the second interferometer. Each interferometer has an output signal versus frequency characteristic with a substantially linear region about a center frequency, which center frequency is approximately equal to the center frequency of the input optical signal. The outputs from the interferometers are combined in a manner such as the difference in absolute value of the linear region characteristic slopes is obtained, the resulting output being a discriminated output which is substantially linear over an enhanced FM range.
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