Method and system for correcting imbalance in in-phase/quadrature demodulation of optical fiber das data

A system for correcting imbalance in IQ demodulation of optical fiber DAS data, comprising:

• an obtaining module, configured to obtain I/Q signals I0 and Q0 of each sampling on an optical fiber;
• a DC bias correction module, configured to perform DC bias correction on the I/Q signals I0 and Q0 to obtain I/Q signals I1 and Q1 after DC bias correction;
• an amplitude imbalance correction module, configured to perform an amplitude imbalance correction on the I/Q signals I1 and Q1 after DC bias correction by using Hilbert transform to obtain I/Q signals I2 and Q2 after amplitude imbalance correction;
• and
• a phase imbalance correction module, configured to perform phase imbalance correction on the I/Q signals I2 and Q2 after amplitude imbalance correction by using Hilbert transform to obtain I/Q signals I3 and Q3 after phase imbalance correction,
• wherein the performing an amplitude imbalance correction on the I/Q signals I1 and Q1 after DC bias correction by using Hilbert transform to obtain I/Q signals I2 and Q2 after amplitude imbalance correction comprises:
• calculating corresponding amplitude imbalance factors Ai and Aq by using Hilbert transform and the I/Q signals I1 and Q1 after DC bias correction;
• and
• performing the amplitude imbalance correction on the I/Q signals I1 and Q1 after DC bias correction according to the amplitude imbalance factors Ai and Aq to obtain the I/Q signals I2 and Q2 after amplitude imbalance correction.