RU1841279C - The method of measuring the angular velocities of objects using a ring optical quantum generator - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: invention relates to methods for measuring the angular velocities of objects using annular optical quantum generator (1). Essence: electromagnetic waves of opposing beams are polarized in mutually perpendicular planes, for example, using mirrors (2), and are passed through nonreciprocal element (3). Mutually perpendicularly polarized electromagnetic waves are separated beyond the resonator, for example, using Wollaston prisms (4). Opposing waves with identical polarizations are combined, two difference frequencies are separated and compared on detector (8), and the angular velocity is extracted.

EFFECT: technical result: increase of accuracy and expansion of the measuring range.

1 cl, 1 dwg

Description

The present invention relates to angular velocity sensors based on annular optical quantum generators and can be used to create high-precision quantum gyroscopes, angular velocity meters, magnetic compasses and other devices.

Usually, in ring optical quantum generators, a nonreciprocal element based on the Faraday effect [1] is used to overcome the synchronization of the frequencies of two opposite rays and to discriminate the sign of the angular displacements. This element is installed in the resonator of a ring optical quantum generator with respect to the direction of the generated rays normally or at the Brewster angle.

In ring optical quantum generators with an active element having output windows at the Brewster angle, the radiation has a linear polarization. When radiation passes through a nonreciprocal element, to which a longitudinal magnetic field is applied, the electromagnetic wave acquires an additional phase shift depending on the magnitude and direction of the magnetic field. As a result of this, the frequencies of the beams of a ring optical quantum generator will differ by an amount determined by the expression:

where R is the Verde constant; H is the intensity of the magnetic field in the direction of propagation of the rays; l _ne - the length of the path of the rays in a non-reciprocal element; l _p - the length of the perimeter of the resonator.

Now, with the angular displacements of a ring optical quantum generator, its frequencies will change in accordance with the magnitude and sign of the angular velocity. The frequencies of the rays will be determined by the following expressions:

, определяемый выражением:where ν _o is the frequency of the radiation at rest of the ring laser in the absence of frequency splitting by a non-reciprocal element; ν _p - the frequency of the beam extending clockwise; ν _l - the frequency of the beam propagating counterclockwise; F _pn - the frequency of splitting, due to non-reciprocal element; F _Ω is the splitting frequency due to rotation with an angular velocity Ω. In this case, the direction of the magnetic field is such that its action coincides in sign with the action of the angular displacement. After selecting the difference in optical frequencies, the frequency shift is obtained.

defined by the expression:

To measure F _Ω and, therefore, the angular velocity, it is necessary to exclude F _ph . This is achieved by switching the magnetic field in a non-reciprocal element.

With the opposite direction of the magnetic field, the frequency shift will be determined by the expression:

If from (4) we subtract (5), we get:

By a known ratio:

S is the area covered by the ray path;

ν is the frequency of the rays in the located ring optical quantum generator;

l _p - the length of the perimeter of the resonator, we find the magnitude of the angular velocity Ω.

за время ΔT. Затем производится коммутация поля. На это тоже необходимо время Δt. После этого измеряется количество импульсов сигнала частоты

за то же время ΔT. Результаты измерений алгебраически складываются, и таким образом находится ΔF_p и, следовательно, угловая скорость.Almost the measurement of the angular velocity is as follows. Measuring the number of pulses with frequency

during ΔT. Then the field is switched. It also takes time Δt. After that, the number of pulses of the frequency signal is measured.

during the same time ΔT. The measurement results are algebraically added, and thus ΔF _{p is found} and, therefore, the angular velocity.

This method of measurement allows to obtain the averaged values of angular velocities during the measurement 2ΔT and only partially get rid of the influence of the instability of the magnetic field on the measurement accuracy.

A method for measuring angular velocities is proposed, aimed at ensuring continuous measurement of angular velocities and eliminating the influence on the accuracy characteristics of a sensor with an annular optical quantum generator and a non-reciprocal element of magnetic field instability.

Consider the dynamics of the system that implements the proposed method, presented in Fig. 1, where:

1 - ring optical quantum generator;

2 - polarizing mirrors;

3 - non-reciprocal element;

4 - Wollaston prisms;

5 - mirrors for combining rays with the same polarization;

6 - translucent plates;

7 - means for separation of the difference frequency;

8 - the detector.

- частота волны, поляризованной в горизонтальной плоскости, распространяющейся против часовой стрелки; ν_л⊕ - частота волны, распространяющейся против часовой стрелки и поляризованной в вертикальной плоскости;

- частота волны, поляризованной в горизонтальной плоскости и распространяющейся по часовой стрелке; ν_п⊕ - частота волны, поляризованной в вертикальной плоскости, распространяющейся в направление по часовой стрелки;

- разностная частота от волн с горизонтальной поляризацией; F_p⊕ - разностная частота волн с вертикальной поляризацией; ΔF_p - разностная частота от углового перемещения.

- frequency of a wave polarized in a horizontal plane, propagating counterclockwise; ν _l⊕ - the frequency of the wave propagating counterclockwise and polarized in the vertical plane;

- frequency of a wave polarized in a horizontal plane and propagating clockwise; ν _n⊕ is the frequency of a wave polarized in a vertical plane extending in a clockwise direction;

- difference frequency from waves with horizontal polarization; F _p⊕ - difference frequency of waves with vertical polarization; ΔF _p - difference frequency from the angular displacement.

When a field H is applied to a non-reciprocal element, the frequencies of electromagnetic waves change by an amount determined by expression (1), and the sign of the change is determined by the direction of rotation of the polarization plane of the wave inside the non-reciprocal element relative to the direction of the magnetic field [1].

Since the planes of polarization of the waves of a ring optical quantum generator, propagating in one direction, are mutually perpendicular, then inside the non-reciprocal element they will have oppositely rotating polarization planes. Consequently, they will receive a frequency shift in magnitude in accordance with c (1), but opposite in sign. The same will happen with the frequencies of the opposing waves. The values of the frequencies of these waves will be determined by the relations:

. Допустим, что ν_л⊕ от вращения изменилось и определяется в соответствии с выражением:In a rotating ring optical quantum generator, all frequencies will be changed by

. Suppose that the ν _l⊕ from the rotation has changed and is determined in accordance with the expression:

Then the frequencies of the other waves will be determined by the following expressions:

Combining the rays with the same polarization outside the resonator of the ring optical quantum oscillator, we distinguish the difference in their frequencies by known methods. It will be defined by the following expressions:

 - for electromagnetic waves with vertical polarization;

, получаем выражение для ΔF_p.- for electromagnetic waves with horizontal polarization. Then, highlighting the difference between F _p⊕ and

, we obtain the expression for ΔF _p .

Knowing F _Ω , we find the magnitude of the angular velocity.

Thus, the proposed system achieves the same result as before, namely, the measurement of the angular velocity, but without switching the direction of the magnetic field. Therefore, we have the ability to measure the angular velocity at any time.

Since expression (14) does not include the value of the frequency shift from the magnetic field, and the measurement of ΔF _{p is} performed continuously, the effect of the instability of the magnetic field in the proposed method is completely excluded.

, обусловленный только магнитным полем. Изменение величины

будет нести информацию об изменении внешнего магнитного поля.In conclusion, we note that the proposed method can be used to measure the magnitude and the external component of the magnetic field. To do this, add (12) and (13) in order to isolate the signal

due to magnetic field only. Change in magnitude

will carry information about changes in the external magnetic field.

Literature:

1. Vasiliev, V.P. "Questions of special electronics". Series XII, issue. 14, 1965, p. 3-20.

Claims (1)

The method of measuring the angular velocities of objects using an annular optical quantum generator, in which the electromagnetic waves of the oncoming rays polarize in mutually perpendicular planes, for example, using mirrors, and pass through a non-reciprocal element, characterized in that determining the direction of the angular displacement, electromagnetic waves with mutually perpendicular polarizations are separated outside the resonator, for example, using Wollaston prisms, combine opposite waves with the same polarizations, select two difference frequencies, compare them at the detector and highlight the angular velocity.

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