Method for determining half-wave voltage of phase modulator

Abstract

The invention discloses a method for determining half-wave voltage of a phase modulator. The method comprises the steps that firstly, voltage of a phase position 0pi, voltage of a phase position pi / 2, voltage of a phase position pi, voltage of a phase position 3pi / 2 of an emitting end are calculated; secondly, voltage of a phase position 0pi, voltage of a phase position pi / 2, voltage of a phase position pi, voltage of a phase position 3pi / 2 of a receiving end are calculated; thirdly, the voltage of the phase position pi / 2 is found, the phase voltage of the emitting end of the phase modulator is stabilized to pi / 2, scanning is performed from the minimum value to the maximum value of the voltage range of the receiving end of the phase modulator, a sine curve Q2 is obtained, the corresponding position of the maximum point and the corresponding position of the minimum point of the receiving end are found through fitting, the maximum point corresponds to the voltage of the phase position pi / 2 of the receiving end, and the voltage of the phase position pi / 2 of the receiving end is B2; fourthly, whether the voltage of the phase position pi / 2 and the voltage of the phase position 3pi / 2 of the emitting end are interchanged is determined. According to the method, the half-wave voltage can be accurately calculated when the external environment is changed, and the direction of modulation can be judged. In this way, the phase position of a photon can be accurately modulated so that interference can occur at the two ends.

Description

[0001] technical field [0002] The invention relates to a method for determining the half-wave voltage of a phase modulator by accurately calculating the half-wave voltage and judging the modulation direction when the external environment of the phase modulator changes. Background technique [0003] Phase modulators are widely used in optical experiments to modulate the phase of photons. However, due to the change of the external environment, the half-wave voltage of the phase modulator is constantly changing, and the phase of the phase modulator at the transmitting end and the receiving end is no longer the same. Matching, interference cannot occur, and the direction of the modulation change of the same type of phase modulator does not necessarily change in the same direction with the increase or decrease of the applied voltage, and may be in the opposite direction. At this time, the 0π and π of the phase modulator at one end The voltage does not need to be changed, but th...

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Problems solved by technology

[0003] Phase modulators are widely used in optical experiments to modulate the phase of photons. However, due to the change of the external environment, the half-wave voltage of the phase modulator is constantly changing, and the phase of the phase modulator at the transmitting end and the receiving end is no longer the same. Matching, interference cannot occur, and the direction of the modulation change of the same type of phase modulator does not necessarily change in the same direction with the increase or decrease of the applied voltage, and may be in the opposite direction. At this time, the 0π and π of the phase modulator at one end The voltage does not need to be changed, but the voltages of π / 2 and 3π / 2 need to be reversed, so a method is needed to accurately calculate the half-wave voltage and judge the direction of modulation change

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