Underground optical fiber flow sensor in oil field

The invention relates to a petroleum logging instrument, and particularly to an underground optical fiber flow sensor in an oil field. A light source module of the sensor is connected to a polarization controller; the polarization controller is connected to an optical fiber coupler; the optical fiber coupler is respectively connected to a phase modulator, a Faraday rotating head II and a photoelectric detector; the phase modulator, a Faraday rotating head I and an optical fiber pressure sensing head I are connected sequentially; the Faraday rotating head II is connected to an optical fiber pressure sensing head II; and the photoelectric detector, an amplification circuit and an A/D (Analogue/Digital) converter and an embedded computer are connected sequentially. The underground optical fiber flow sensor in the oil field realizes absence of direct function of a fluid and optical waves, can realizes wholly sealed packaging, satisfies fluid flow measurement in a high-temperature and high-pressure severe environment, has high measurement sensitivity and high measurement precision, and overcomes the disadvantage that the conventional optical fiber sensor cannot be satisfied with the environment requirements of the underground flow measurement of petroleum.