OPTICAL POWER LIMITER CIRCUIT AND METHOD

摘要

PROBLEM TO BE SOLVED: To provide an optical power limiter circuit and method for performing satisfactory operation with low optical power without using an optical fiber and a passive component.

SOLUTION: The optical power limiter circuit is so constituted that an optical signal 25 from a signal processing system and a probe beam 26 having a wavelength different from the wavelength of the optical signal 25 from a probe beam generator 23 are inputted to a semiconductor optical amplifier 22. The probe beam 26 is amplified by optical gain of the semiconductor optical amplifier 22, but gain to the probe beam 26 is reduced only for the time at which the optical signal 25 is inputted since carrier density is reduced in an induction and emission process in which the optical signal 25 is amplified. Thereby, a signal having intensity of a high level/a low level reverse to that of the optical signal 25 is converted to the wavelength of the probe beam 26. A wavelength filter 24 selectively takes out only an optical signal 28 corresponding to the optical signal 25 among the optical signals 27 to 29 outputted from the semiconductor optical amplifier 22.

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