RU2157962C2 - Method for supplementary phase modulation of ring interferometer of fiber-optical gyro - Google Patents

Abstract

FIELD: fiber-optical equipment. SUBSTANCE: device may be used for design of electronic information processing unit for fiber- optical gyro or other detectors of physical values. method involves application of voltage to wide-band phase modulator in order to achieve supplementary phase modulation. Voltage is applied as sequence of discrete pulses, which frequency depends on time for traveling beam in light guide of sensitive coil of interferometer τ = Ln₀/C, where L is light guide length of sensitive coil, n₀ is refraction index of light guide material, C is light speed in vacuum. Phase difference of interferometer beams is represented as pulse sequence of T_o period, which has two periods, which duration is KT_o ¹ and NT_o ², respectively, where K and N are natural numbers, T_o ¹ is time period for which phase modulation is achieved as periodic pulse sequence with amplitude of ±(π-Δ). Duration of single pulse is m, where m is natural number, which conforms to condition m = T $\genfrac{}{}{0ex}{}{\text{1}}{\text{0}}$ /2τ. T_o ² is time period, for which phase modulation is achieved also as periodic pulse sequence with amplitude of ±(π+Δ) and pulse duration of nτ, where n is natural number, which conforms to condition n = T $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ /2τ. Delta is within range of 0,05π ≤ Δ ≤ 0,95π. EFFECT: decreased weight and size of gyro, decreased power consumption. 2 cl, 9 dwg

Description

 The invention relates to the field of fiber optics and can be used in the design of an electronic unit for processing information of a fiber-optic gyroscope, as well as other sensors of physical quantities based on a ring interferometer.

 There is a method of implementing auxiliary phase modulation in a ring interferometer of a fiber-optic gyroscope [1], which solves two problems: transferring the operating point of the interferometer to a zone of increased sensitivity to rotation, as well as stabilizing the scale factor of the gyroscope.

In [1], a method of auxiliary phase modulation is proposed, which simultaneously solves the problem of transferring the operating point of the gyroscope to a zone of higher sensitivity, as well as obtaining information about the voltage on the phase modulator corresponding to the introduced phase shift of radians, from which the phase sensitivity of the modulator is calculated in any moment in time, which in turn allows you to adjust the scale factor of the gyroscope. Auxiliary phase modulation is carried out using a sequence of rectangular pulses following a frequency f _opt = s / 2Ln ₀ , where c is the speed of light in vacuum, L is the fiber length of the sensitive coil of the ring interferometer, n ₀ is the refractive index of the fiber material. The frequency f _opt is considered optimal for auxiliary phase modulation. In addition, in [1], an additional modulation of the auxiliary phase modulation signal is proposed, which consists in the fact that a positive pulse of auxiliary phase modulation of duration τ = Ln ₀ / c, one of its half in duration (1 / 2τ) has an amplitude that introduces phase shift equal to 2 / 3π, and in its second half in duration (1 / 2τ) has an amplitude that introduces a phase shift of 4 / 3π. With this form of voltage applied to the phase modulator of the ring interferometer, in the presence of rotation of the gyroscope, a signal appears at the gyro photodetector at a frequency f _opt = c / 2Ln ₀ , the amplitude of which is proportional to the angular velocity of the gyroscope. In this case, the working point of the gyroscope is shifted practically to the zone of maximum sensitivity to rotation.

Additional modulation of the auxiliary phase modulation signal is necessary in order to obtain information about the correspondence of the voltage value on the phase modulator to the value of the introduced phase shift. In the case under consideration, if for some reason, for example, when the wavelength of the radiation source changes, the phase shift in the first half of the pulse duration will not be ± 2 / 3π, and in the second half of the pulse duration it will not naturally be ± 4 / 3π, then a signal appears on the photodetector, which follows with a frequency f = c / Ln ₀ and with an amplitude proportional to the voltage mismatch in the form of a half pulse introduced by a phase shift of ± 2 / 3π and ± 4 / 3π, respectively. After isolating the amplitude of the signal following with a frequency f = c / Ln ₀ , the amplitude of the pulse of the auxiliary phase modulation signal is adjusted until the amplitude of this signal vanishes. In this steady state, the sum of the voltage in the first half of the pulse and the voltage in the second half of the auxiliary phase modulation pulse corresponds to an introduced phase shift of 2π radians, which is used to correct the gyroscope scale factor.

The disadvantages of the proposed method for the implementation of auxiliary phase modulation are as follows:
1. High frequency signal carrying information about the angular velocity of rotation of the gyroscope.

2. An even higher frequency of the signal of the mismatch of voltage values in two halves of the pulse of the auxiliary phase modulation signal, which leads to a mismatch of the position of the operating points with the points ± 2 / 3π and ± 4 / 3π.
The high frequency of the working signals leads to a deterioration of the noise immunity of the circuit, which forces the use of additional electronic components, which in turn degrades the weight and size characteristics of the gyroscope. A higher frequency of working signals also requires an electronic base with a higher level of energy consumption, which leads to an increase in energy consumption of the entire gyroscope as a whole.

 The aim of the present invention is to improve the overall dimensions of the gyroscope and reduce its energy consumption.

This goal is achieved by the fact that according to the method, which consists in applying voltage to a broadband phase modulator, with the aid of which auxiliary phase modulation is carried out in the form of a sequence of step pulses following with a frequency determined by the beam travel time through the optical fiber of the sensitive coil of the interferometer τ = Ln ₀ / c where L - length of the fiber sensing coil, n ₀ - index of refraction of the fiber material, c - velocity of light in vacuum to the phase difference of the interferometer beams is formed as pos pulses edovatelnosti with period T _0, which comprises two periods with a duration of each respectively KT ₀ ¹ and NT ₀ ² where K, N - positive integers and T ₀ ¹ - the length of time during which the phase modulating periodically in a pulse sequences with amplitude ± (π-Δ) and duration of one pulse mτ, where m is a positive integer and m = T ₀ ^1/2 τ; T ₀ ² - time during which the phase modulating periodically in a pulse train with an amplitude of ± (π + Δ) and duration nτ, where n - is a positive integer, n = T ₀ ^2/2 τ wherein Δ is selected in the range 0 , 05π≤Δ≤0.95π radians.

Улучшение массогабаритных характеристик гироскопа и уменьшение его энергопотребления достигается за счет снижения частоты сигнала, несущего информацию о вращении, а также частоты сигнала рассогласования уровней напряжения, которые должны соответствовать фазовым сдвигам на фазовом модуляторе ±(π-Δ) и ±(π+Δ), так как при понижении частот рабочих сигналов нет необходимости повышения помехозащищенности схемы с помощью дополнительных электронных устройств и экранов. Пониженные рабочие частоты также позволяют снизить энергопотребление электронных компонентов схемы.This goal is also achieved by the fact that according to the phase modulation method in the ring interferometer of a fiber-optic gyroscope, which consists in applying a voltage to a broadband phase modulator, with the help of which an auxiliary phase modulation is carried out in the form of a sequence of step pulses following with a frequency determined by the beam time from sensitive optical fiber coil interferometer τ = Ln ₀ / c, where L - length of the fiber sensing coil, n ₀ - index of refraction of the fiber material, c - MSE awn light in a vacuum, the phase difference of beams of the interferometer is formed as a sequence of pulses with period T ₀ in the first half of which form the sequence of pulses with an amplitude of - (π-Δ) with a length mτ + (π + Δ) with a length nτ and - (π -Δ) with a duration nτ, where n is a positive integer and m ≥ 2n, and in the second half of the period T ₀ a pulse train with amplitudes + (π-Δ) with a duration of mτ, - (π + Δ) with a duration of nτ and + (π-Δ) with duration mτ, and

Improving the weight and size characteristics of the gyroscope and reducing its energy consumption is achieved by reducing the frequency of the signal that carries rotation information, as well as the frequency of the voltage signal mismatch, which must correspond to phase shifts on the phase modulator ± (π-Δ) and ± (π + Δ), since when lowering the frequencies of the working signals there is no need to increase the noise immunity of the circuit using additional electronic devices and screens. Lower operating frequencies also reduce the power consumption of electronic circuit components.

 The invention is illustrated in FIG. 1 to 9. In FIG. 1 shows a block diagram of a fiber optic gyroscope. In FIG. Figure 2 shows a general view of the pulse sequence of the auxiliary phase modulation and the voltage plot on the broadband phase modulator, with which this auxiliary phase modulation is achieved in the gyro ring interferometer. In FIG. 3 shows a view of auxiliary phase modulation and corresponding voltage plots on a broadband phase modulator at Δ = 1 / 3π; m is 2; n is 2; K = 2; N = 2. In FIG. Figure 4 shows the general principle of generating a useful signal carrying rotation information. In FIG. Figure 5 shows the general principle of generating a mismatch signal when the operating points of the gyroscope are located asymmetrically with respect to the phase shift of ± π radians in the gyroscope ring interferometer. In FIG. 6 shows a pulse sequence of phase modulation according to the proposed second method and a sequence of step voltage, upon supply of which the proposed phase modulation is implemented. In FIG. 7 shows, respectively, a sequence of step voltage and a sequence of phase modulation pulses realized by means of the proposed method with m = 4 and n = 2. FIG. 8 shows the general principle of generating a signal that carries rotation information using the proposed phase modulation for m = 4, n = 2. FIG. Figure 9 shows the general principle of generating a mismatch signal when the operating points of the gyroscope are located asymmetrically with respect to the phase shift of π radian in the ring interferometer using phase modulation in the second way in the case when m = 4 and n = 2.

 The fiber-optic gyroscope (Fig. 1) contains a fiber optic ring interferometer 1, which also includes a broadband phase modulator 2, for example, a modulator based on a lithium niobate plate [1, 2], and a photodetector 3. The signal from the photodetector 3 is fed to synchronous amplifier 4, which distinguishes the gyroscope rotation signal, and to synchronous amplifier 5, which distinguishes the mismatch signal between voltage levels on the modulator in the case of asymmetric arrangement of the gyroscope operating points with respect to ± π rad (voltage level mismatch signal). The generator 6 generates the voltage supplied to the phase modulator, with the help of which a pulse sequence of auxiliary phase modulation is generated by the proposed method, as well as the synchronizing signals that are fed to the corresponding inputs of synchronous amplifiers 4, 5, to highlight the voltage levels corresponding to the amplitudes of the signal carrying information about the rotation and amplitude of the voltage level mismatch signal.

 The control circuit 7 of the amplitude of the modulating voltage generated by the generator 6, adjusts the levels of this voltage so that the error signal turns into "0".

The signal processing of a fiber optic gyro is as follows. Phase modulator 2 introduces between the beams of the interferometer an auxiliary phase modulation in the form of a pulse sequence 8 (Fig. 2) with a period T ₀ , which is divided into 2 times KT ₀ ¹ and NT ₀ ² , where K, N are positive integers and KT ₀ ¹ + NT ₀ ² = T ₀ .

During the first time interval CT ₀ ¹ , the auxiliary phase modulation signal is generated in the form of a pulse sequence with a period T ₀ ¹ and the introduced phase modulation level ± (π-Δ) radian, and Δ can be selected in a wide range of 0.05π≤Δ≤0, 95π. The duration of each introduced phase modulation level ± (π-Δ) is mτ, where τ = Ln ₀ / c is the travel time of the light beam through the fiber of the sensitive coil of the ring interferometer, and m = T ₀ ¹ / 2τ.

During the second time interval NT ₀ ² , an auxiliary phase modulation signal is generated in the form of a pulse sequence with a period T ₀ ² and the introduced phase modulation levels ± (π-Δ) radians. The duration of each level of the phase modulation introduced by ± (π-Δ) amounts nτ, wherein n = T ₀ ^2/2 τ.

где Φ_C - разность фаз Саньяка:
R - радиус чувствительной катушки интерферометра;
L - длина световода чувствительной катушки;
λ - длина волны источника излучения;
c - скорость света в вакууме;
Ω_пр - угловая скорость вращения.Auxiliary phase modulation in the form of a pulse sequence 8 can be formed by applying to the phase modulator 2 a pulse sequence of step voltage 9 with a period T ₀ , which is also divided into two time intervals KT ₀ ¹ and NT ₀ ² . In the first half-period T ₀ ^1/2 , increasing voltage steps are formed with the number m + 1, with the duration of each step τ and voltage drops of adjacent steps of such a magnitude that, when applied to the phase modulator, they change the phase of the rays by the value - (π-Δ) . In the second half cycle T ₀ ^2/2 are formed with decreasing step duration τ and differential stresses adjacent steps, introducing a phase shift + (π-Δ).
During the NT ₀ ² segment, a sequence of step voltage is formed with a period T ₀ ² , in the first half period of which decreasing steps are formed with the number n + 1 with a duration of each step τ and voltage drops of adjacent steps of such a magnitude that, when applied to the phase modulator, they change phase of the rays by ± (π + Δ). In the second half cycle T ₀ ^2/2 incremental forming step with a duration τ and difference adjacent steps, introducing a phase shift - (π-Δ).
To analyze the information processing scheme of a fiber-optic gyroscope, we consider a particular case, namely Δ = 1 / 3π; m is 2; n is 2; K = 2; N = 2. In this case, the sequence of step voltage supplied to the phase modulator takes the form 10 (Fig. 3), while the pulse sequence of the auxiliary phase modulation takes the form 11. In FIG. 4 shows the principle of generating a signal carrying rotation information. When the gyroscope annular interferometer rotates between its rays, a Sagnac phase difference occurs:

where Φ _C is the Sagnac phase difference:
R is the radius of the sensitive coil of the interferometer;
L is the fiber length of the sensitive coil;
λ is the wavelength of the radiation source;
c is the speed of light in vacuum;
Ω _CR - the angular velocity of rotation.

The dependence of the radiation intensity at the photodetector 3 of the gyroscope is described by the expression
I _f ~ 1 + cos (Φ _C + Φ _mod ),
where Φ _mode is the auxiliary phase modulation II formed by the proposed method.

при m = n, т.е. при этом условии частота полезного сигнала, несущего информацию о вращении, может быть существенно снижена по сравнению с оптимальной частотой f_орт = с/2Ln₀, которая обычно используется при обработке сигнала гироскопа.Graphically, the signal generation process can be explained using the cosine curve 12 (Fig. 4). When applying pulse sequence II in the absence of rotation, the intensity level at the photodetector remains unchanged. When the gyroscope rotates, the modulating signal shifts either to the right or to the left, depending on the direction of rotation. In this case, a sequence of pulses 13 appears at the photodetector with a frequency f ₀ and amplitude proportional to the angular velocity of rotation. In this particular case, the frequency of the desired signal

for m = n, i.e. under this condition, the frequency of the desired signal indicative of the rotation may be significantly reduced compared with the optimal frequency f = _{unit vector} from / 2Ln _0, which is commonly used in the processing of the gyro signal.

Рассмотрим кольцевой волоконный интерферометр с длиной световода чувствительной катушки L = 10³ м. Для такого интерферометра

В случае, например: m = 2, n = 2, K = 10, N = 10
f₀ =f_опт/2 = 50 кГц;

т. е. с помощью предлагаемой импульсной последовательности вспомогательной фазовой модуляции может быть осуществлено значительное снижение частоты полезного сигнала, несущего информацию о вращении, а также сигнала рассогласования уровней напряжения последовательности ступенчатого напряжения, подаваемого на фазовый модулятор.But due to the effect on the phase modulator, which can change its efficiency, for example, the change in electro-optical coefficients under the influence of ambient temperature or the wavelength of optical radiation, which also changes the efficiency of the phase modulator, the pulse amplitudes of the auxiliary phase modulation can change, despite the fact that the voltage applied to the phase modulator remains unchanged. In FIG. 5 shows the general principle of generating a mismatch signal for the case considered above, i.e. m is 2; n is 2; K = 2; N = 2; Δ = 1 / 3π, when the efficiency of the phase modulator increases due to some external influences. By increasing the auxiliary pulse 11 amplitude phase modulation signal at the photodetector is formed of the form 14, the pulse repetition frequency f _races which is 4 times lower than the frequency of the desired signal indicative of the rotation. For the frequency of the mismatch signal with m = n, K = N, the following relation holds:

Consider a ring fiber interferometer with a fiber length of the sensitive coil L = 10 ³ m. For such an interferometer

In the case, for example: m = 2, n = 2, K = 10, N = 10
f ₀ = f _opt / 2 = 50 kHz;

i.e., using the proposed pulse sequence of auxiliary phase modulation, a frequency of the useful signal carrying rotation information can be significantly reduced, as well as the voltage level matching signal of the step voltage sequence supplied to the phase modulator.

 In the case considered above, for Δ = 1 / 3π, the working points of the gyroscope on the cosine curve 12 are -4.3π, -2 / 3π (located symmetrically relative to the point -π rad) and 2 / 3π, 4 / 3π (located symmetrically relative to π rad ) The mismatch signal appears when this symmetry of the location of the operating points relative to π radians and -π radians is broken due to an increase or decrease in the amplitude of the pulses of the auxiliary phase modulation. When a mismatch signal appears at the output of the synchronous amplifier 5, it goes to the control circuit 7 of the amplitude of the sawtooth step voltage supplied from the generator 6 to the phase modulator 2. The control circuit changes the levels of the sawtooth step voltage so that the mismatch signal vanishes. In this case, the operating points of the gyroscope are located symmetrically with respect to the points π rad - π rad. The difference in voltage levels ΔU on the phase modulator, introducing phase shifts of 2 / 3π and -4 / 3π ,, exactly corresponds to the introduced phase difference of 2π rad. Thus, the efficiency of the phase modulator in this case is precisely known, i.e.

Обычно, при обработке сигнала гироскопа используют компенсационные схемы, т.е. возникающую за счет вращения разность фаз Саньяка компенсируют с
помощью того же фазового модулятора 2 напряжением определенного уровня, зануляя тем самым сигнал на выходе синхронного усилителя 4. В этом случае справедливо соотношение

где η_эфф - эффективность фазового модулятора;
U_к - напряжение компенсации
Таким образом,

Величина η_эффλ•c/4πRL
в данном случае называется масштабным коэффициентом гироскопа и определяет в конечном счете его точностные характеристики. Как видно из выражения для масштабного коэффициента, он в значительной степени зависит от стабильности эффективности фазового модулятора, но предлагаемый способ вспомогательной фазовой модуляции позволяет иметь текущее значение эффективности фазового модулятора в любой момент времени, что позволяет повысить точность гироскопа путем постоянной коррекции значения масштабного коэффициента.

Usually, when processing the gyro signal, compensation schemes are used, i.e. The Sagnac phase difference resulting from rotation is compensated by
using the same phase modulator 2 with a voltage of a certain level, thereby nullifying the signal at the output of the synchronous amplifier 4. In this case, the relation

where η _eff is the efficiency of the phase modulator;
U _to - compensation voltage
Thus,

The value η _eff λ • c / 4πRL
in this case, it is called the scale factor of the gyroscope and ultimately determines its accuracy characteristics. As can be seen from the expression for the scale factor, it largely depends on the stability of the phase modulator efficiency, but the proposed method of auxiliary phase modulation allows you to have the current value of the phase modulator efficiency at any time, which allows to increase the gyroscope accuracy by constantly correcting the scale factor value.

 When choosing Δ≤0.95π and Δ≥0.05ππ, the sensitivity of the ring interferometer to rotation decreases very quickly, so Δ is chosen in the range of 0.05π≤Δ≤0.95π radians.

The signal processing of a fiber optic gyroscope according to claim 2 of the formula is as follows. The phase modulator 2 introduced between the arms of the interferometer auxiliary phase modulation in the form of a pulse train 15 (Figure 6.) With a period T ₀ in the first half cycle wherein T ₀ ^2/2 signal is generated auxiliary phase modulation in the form of three pulses with the amplitude of the first and third pulses - (π-Δ) radians and durations mτ, where m is a nonzero positive integer, and τ is the travel time of the light beam along the fiber of the sensitive coil of the interferometer and with the amplitude of the second pulse + (π + Δ) radians and duration nτ, where n - not ra positive zero integer. In the second half cycle of the pulse sequence T ₀ -T _0/2 signal is generated as an auxiliary of the phase modulation in the form of three pulses with the amplitudes of the first and third pulses of + (π-Δ) radians and durations mτ, and the second pulse has an amplitude of - (π + Δ) rad and duration nτ. This type of auxiliary phase modulation can be formed by applying a voltage to the phase modulator of the interferometer in the form of a sequence of step pulses changing according to a sawtooth law 16. The duration of each step of this pulse sequence is τ. The difference in neighboring voltage levels for this sequence is such that the phase difference of the rays is introduced through the modulator either (π-Δ) or (π + Δ). If we denote by α the number of voltage levels, the difference in neighboring levels of which is introduced by the phase difference (π-Δ) radian, then the number m = α-1, and if we denote by β the number of voltage levels, the difference in neighboring levels of which introduces the phase difference (π + Δ ), then the number n = β-1.
In FIG. 7 shows a special case when m = 2, and n = 2. In this case, the sequence of step pulses, changing according to the sawtooth law, takes the form 17. For such values of m and n, Δ = 1/3 radians, i.e. The pulse phase modulation sequence 18 has the following levels: -4 / 3π; + 4 / 3π; with a duration of 2π and levels -2 / 3π; 2 / 3π radians with a duration of 4τ ..

т.е. в нашем частном случае

что приводит к значительному уменьшению частоты сигнала гироскопа.In FIG. Figure 8 shows the graphical process of signal formation on the photodetector of an interferometer that carries information about the angular velocity of rotation of the gyroscope. When the gyroscope rotates, leading to the appearance of a Sagnac phase difference Φ _C and shifting the pulse sequence 18 either to the left or to the right on the axis of the cosine curve, a signal 19 appears on the photodetector, followed by a modulation frequency

those. in our particular case

which leads to a significant decrease in the frequency of the gyro signal.

т. е. также удается значительно снизить частоту сигнала рассогласования. Разности уровней напряжения, вносящих фазовые сдвиги +(π-Δ) и -(π+Δ) или -(π-Δ) и +(π+Δ) соответствуют вносимым фазовым сдвигам 2π радиан, что может быть использовано для определений η_эфф и для последующей корректировки масштабного коэффициента гироскопа.In FIG. 9 shows a graphical process of generating a mismatch signal when the operating points of the horoscope are -4 / 3π and -2 / 3π; as well as 4 / 3π and 2 / 3π are located asymmetrically relative to the points -π radians and π radians, respectively. This can happen when the efficiency of the phase modulator changes either due to the wavelength of the radiation source, or due to a change in the electro-optical coefficients of the modulator material, etc. In this case, all the amplitudes of the pulse sequence of the phase modulation 18 either increase or decrease by ΔΦ. In the case of an increase in the amplitude of the pulses, a signal 20 appears on the photodetector, which is a pulse signal, following with a frequency

i.e., it is also possible to significantly reduce the frequency of the error signal. Differences in voltage levels introducing phase shifts + (π-Δ) and - (π + Δ) or - (π-Δ) and + (π + Δ) correspond to introduced phase shifts of 2π radians, which can be used to determine η _eff and for subsequent adjustment of the scale factor of the gyroscope.

LITERATURE
[1] SPIE vol. 2292 Fiber Optic and Laser Sensors XII, pp 156 - 165, 1994

 [2] Electrotechnology, Jannary 1989, pp 17-21.

Claims (2)

1. The method of phase modulation in the ring interferometer of a fiber-optic gyroscope, which consists in applying a voltage to a broadband phase modulator, with the help of which an auxiliary phase modulation is carried out in the form of a sequence of step pulses following with a frequency determined by the travel time of the beam along the fiber of the sensitive coil of the interferometer τ = L n ₀ / c, where L is the length of the fiber of the sensitive coil, n ₀ is the refractive index of the material of the fiber, c is the speed of light in vacuum, characterized in that the phase difference of the rays of the interferometer is formed in the form of a sequence of pulses with a period T ₀ , which contains two periods with a duration of each respectively KT ₀ ¹ and NT ₀ ² , where K, N are positive integers, and T ₀ ¹ is the length of time during which phase modulation is carried out in the form of a periodic pulse sequence with an amplitude ∓ (π-Δ) and a pulse duration of mτ, where m is a positive integer and m = T ₀ ¹ / 2τ, and T ₀ ² is the length of time during which the phase modulation also in the form of periodic successive pulses with an amplitude of ± (π + Δ) and the duration of one pulse nτ, where n - is a positive integer and n = T ₀ ² / 2τ, wherein Δ is selected in the range 0,05π ≤ Δ ≤ 0,95π radians. 2. The method of phase modulation in the ring interferometer of a fiber-optic gyroscope, which consists in applying voltage to a broadband phase modulator, with the help of which an auxiliary phase modulation is carried out in the form of a sequence of step pulses following with a frequency determined by the travel time of the beam along the fiber of the sensitive coil of the interferometer τ = L n ₀ / c, where L is the length of the fiber of the sensitive coil, n ₀ is the refractive index of the material of the fiber, c is the speed of light in vacuum, characterized in that the phase difference of the rays of the interferometer is formed in the form of a sequence of pulses with a period T ₀ , in the first half of which a sequence of pulses with amplitudes - (π-Δ) with a duration of mτ, + (π + Δ) with a duration of nτ and - (π-Δ) s is formed of duration mτ, where n is a positive integer and m ≥ 2n, and in the second half of the period T ₀ a pulse train with amplitudes + (π-Δ) with a duration of mτ, - (π + Δ) with a duration of nτ and + (π- Δ) with duration mτ, and

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