Optical sensor, optical current sensor and optical voltage sensor

An optical sensor, comprising:

• a sensor constituted from an optical portion to which light from a light source is lead, and by which light intensity of the light is modulated based on a physical value;
• a first light receiving element and a second light receiving element receiving two elements of divided light having polarized waves which are orthogonally crossing each other;
• a third light receiving element directly receiving light from the light source;
• a variable optical attenuator operating both light which is received by one of the first and the second light receiving elements and light received by the third light receiving element;
• and
• a variable amplifier operating both an output signal from one of the first and the second light receiving elements and an output signal from the third light receiving element, wherein
• both a zero point and sensitivity of a sensor output are calibrated based on a light attenuation factor or an amplification factor which is adjusted when a physical value is detected by calculating a ratio between the output of the third light receiving element and a difference between one of the outputs from the first and second light receiving elements and the third light receiving element.