Patent ID: 8941402
Filing Date: 2015-01-27
Classification: G01R

Abstract:
1. An electromagnetic field measuring apparatus comprising: a laser light source that emits a laser beam having a predetermined frequency as a carrier signal light; a light modulator that generates a modulated light by modulating the carrier signal light at a predetermined local oscillation frequency, and emitting the modulated light; a certain optical component; an electromagnetic field sensor that generates a signal light by exposing the modulated light incident through the optical component to an electromagnetic field of a radio frequency band caused by an object to be measured and thereby modulating the modulated light, and emits the signal light; an optical receiver that receives the signal light from the electromagnetic field sensor through the optical component and outputs an electric signal having a same radio frequency band as the electromagnetic field; a spectrum analyzer that measures a spectrum of the electric signal; and an amplitude level ratio controller that controls an amplitude level ratio between a carrier and a sideband contained in the signal light incident on the optical receiver to a fixed value based on the spectrum of the electric signal measured by the spectrum analyzer.