SU1275322A1 - Phase measuring device - Google Patents

Abstract

The invention relates to a technique of phase measurements and can be used to measure the relative phase shifts of two processes and to obtain two signals that are shifted from one another in phase by a predetermined value. The aim of the invention is to expand the functionality of the device.

Description

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12 To achieve this goal, 1 1 3 modulated optical signal sources are introduced, mutually orthogonal polarizers: 7 and 8, optical wedge 17, linear polarizer 13, photodetector 6, null organ 16. In addition, the device contains beam splitters 18-24, gates 31-34, mirrors 25-30, coherent light source 14, 15 displacement indicator, prisms 9-12, photodetectors 4 and 5, double-sided mirror 35. Sign1

The invention relates to a technique of phase measurements and can be used to measure the relative phase shifts of two processes and to obtain two sigils shifted relative to each other in phase by a predetermined value.

The aim of the invention is to enhance the functionality of the phase meter device by using it both as a phase calibrator and as a phase shift meter, as well as providing a self-test device without external monitoring means.

The drawing shows a diagram of the phase meter device.

The phasometric device contains three sources 1–3 of a modulated optical signal (IMOS) (converters 1–3 electrical voltages per luminous flux), photodetectors 4–6, 93 IMMNO orthogonal circulators: polarizers 7 and 8, first (moving) prism 9 and a second (fixed) prism 10 of variable optical delay, a third 11 and a fourth 12 prism, a linear polarizer 13, a source of coherent light 14, a displacement indicator 15, for example, an interference band counter, a zero-body 16, an optical wedge 17, beam splitters 18 - 24 mirrors 25 - 30, shutters 31 - 34 and double-sided mirror 35.

These elements form two optical channels, optically interconnected by two optical paths of the self-test, the optical channel of the reference signal containing optically connected fifth beam splitter 22, first circular polarizer 7, optical wedge 17, first beam splitter 18, first gate 31 the second beam splitter 19 and the first photodetector 4, the output of which is the first output of the device, the optical channel of the variable phase contains a variable optical delay containing, in series, opt tical connected second circular polarizer 8, the first (movable) prism 9, the second (indiscriminate) prism 10, the second mirror 26 and the third mirror 27 mechanically fixed to the movable

0 by a prism 9 and by which the variable optical delay is optically coupled to an interferometric displacement meter, consisting of coherent light source 14, optically coupled through the sixth beam splitter 23 to the fixed fourth mirror 28, and to the movable third mirror 27 and further on sixth beam splitter 23 with indi cator 15 displacements. The variable optical delay in the variable phase channel is optically coupled through a fifth beam splitter 22, successively optically coupled to the first mirror 25, the third beam splitter 20, the second gate 32, the fourth beam splitter 21, and the second photoreceiver 5, the output of which is the second code of the device. Phase shift 2 will be obtained without a systematic error due to the nonidentity of the photodetectors 4 and 5, which makes it possible to more accurately determine the value of the variable optical delay. It became possible to combine in one device both the functions of the phase calibrator and the functions of the phase meter. In this case, in both modes of operation of the device, the same optical channels are used. 1 il.

The device also contains a first self-checking path, containing optically coupled with the first beam splitter 18, optically connected third shutter 33, a fifth mirror 29, a third prism 11, and a double-sided mirror 35 optically connected with the fourth beam splitter 21 and entering the channel a variable phase, and a second self-checking path, containing optically coupled to the third beam splitter 20, the optically coupled fourth gate 34, the sixth mirror 30, the fourth prism 12 and the double-sided mirror 35, optically The second side connected to the second beam splitter 19, which is connected to the channel of the reference signal, sends the reference electric signal to the first input of the device, which is the input of the first converter 1 (IMOS), which is optically connected to both optical channels through the seventh 24 and n 22 light beam splitters. Two electrical input signals during phase measurements are supplied to the second and third inputs of the device, which are respectively the inputs of the second and third converters 2 and 3 (IMOS) and are optically connected to the second 19 and fourth 21 beam splitters, respectively. b in the channels has a reverse direction, the light fluxes from both optical channels are summed at the output of the fifth beam splitter 22 and further optically connected through the seventh beam splitter 24 to successively optically coupled linear fields izatorom 13, the third photodetector 6 and nulorganom 16

The device in the modes of the phase calibrator, phase meter and self-test modes works as follows,

In the phase calibrator mode, the shutters 33 and 34 are closed, and the shutters 31 and 32 are open. An input voltage of a given frequency is applied to the input of the converter 1. At the output of converter 1, an intensity-modulated light flux appears. At the splitter 22, two streams are generated — reflected and passing. The reflected flow passes through the polarizer 8 and enters the variable optical delay.

(prisms 9 and 10 and mirror 26), after passing through prisms 9 and 10, the luminous flux falls on mirror 26, reflecting from which, re-enters prisms 10 and 9 and then through polarizer 8 to beam splitter 22, passes through it and, reflecting from the mirror 25, goes further through the beam splitters 20 and 21 and the shutter I 32 to the photodetector 5. The forward light flux passed through the beam splitter 22, then goes through the polarizer 7, wedge 17, shutter 31 and beam splitters 18 and 19 to the photoreceiver 41 Thus, two light fluxes are formed — a reference, arriving at the photo The terminal 4, and the carrier signal with a shifted phase, fed to the photodetector 5. The phase shift is changed by moving the moving element of the variable optical delay (by moving the prism 9 along the line AB). The magnitude of the displacement is taken into account by the counter 15 based on the shift of the interference pattern produced by the Michelson interferometer. The effect on the workflows of elements that are not participating in the mode in question is reduced to a decrease in intensity, which is equalized when the device is adjusted using a wedge 17,

In the phase shift meter mode, the shutters 31 and 32 are open, and the shutters 33 and 34 are closed. Voltage transducers 2 and 3 are supplied to the luminous flux with voltages, the phase shift between which must be measured. The luminous flux of the transducer 2, reflected from the divider 19, passes through the shutter 31, the beam splitter 18, the wedge 17, the circular polarizer 7, the beam splitter 22 and hits the beam splitter 24, the luminous flux passing directly through the beam splitter 19 will eventually be delayed the closed shutter 34,

The luminous flux of the transducer 3, reflected from the splitter 21 (the passing part of this flow is delayed by the closed shutter 33), passes through the shutter 32, the splitter 20, reflects from the mirror 25 and falls on the splitter 22, Pass through the splitter 22, the circular polarizer 8 this the stream enters the optical variable

delay (prisms 9 and 10 and mirror 26), Passing through the optical delay, the luminous flux passes again through the polarizer 8 and, reflected from the beam splitter 22, falls on the beam splitter 24.

Thus, two streams with orthogonal circular polarization are superimposed on the splitter 24. By changing the value of the variable optical delay (prisms 9 and 10 and mirror 26), it is possible to achieve the equality of the phases of the light fluxes incident on the beam splitter 24. At this moment these streams have equal intensity. Due to the fact that circular polarizers 7 and 8 are mutually orthogonal at the time of coincidence of the phases of the signals modulating these streams, the resulting luminous flux is linearly polarized and delayed by a linear polarizer 13 if it is oriented in advance orthogonal to polarization of the resulting stream. Due to this, the zero-body 16 marks the minimum current in the photodetector 6, noting with the help of an interference sensor the amount of movement of the moving element of the variable optical delay, we obtain the value of the introduced phase4 shift, which compensated for the measured phase difference. Calibrating the interference fringe counter directly in the phase angles, you can get the desired measurement result. In self-checking modes, the control of the correspondences of the zeros of the variable optical delay and the nullorgan, as well as the control of the moving element of the optical delay, is performed. In the mode of monitoring the correspondences of the zeros of the displacement meter of the optical delay and the zero body 16 to the transducers 2 and electric oscillations are supplied with the same phase. Using a variable optical delay, a null zero-body reading of 16 is obtained, as in the indicated phase difference mode. The magnitude of the input variable optical phase delay phase shift shows the magnitude of the systematic error in the phase shift measurement mode. In the mode of controlling the position of a moving element of a variable optical delay using a converter l 1, modulated light is generated.

The bulk flow that creates on the photodetectors 4 and 5 is a reference signal and a signal with a shifted phase. Two measurements are made: the first is when the valves 31 and 32 are open and the 33 and 34 are closed, the second is when the valves 31 and 32 are closed and 33 and 34 are open.

In the first measurement, the luminous flux of the transducer 1 passes through the beam splitter 22, the shutter 31 and hits the photoreceiver 4, and the light flux reflected by the beam splitter 22 passes through the variable optical delay and hits the photodetector. In the second measurement, the light output of the transducer 1 passes through a beam splitter 22, shutter 33, prize 11, is reflected from the mirror 35 and the beam splitter 21, hits the photodetector 5, a. the light beam reflected by the beam splitter 22 passes through an optical variable delay and, having broken from the beam splitter 20, passes through the shutter 34, the prism 12, retracts from the mirror 35 and the beam splitter hits the photodetector 4. Let the first measurement be at the photodetector output.4 the value of ot., the absolute phase with an error. , and at the exit. de photodetector 5 - the value of t: f. with an error D of the relative phase shift in the first measurement, we obtain ot, –Y + Aoi, –YY, H– + Ч, where is the intensive value of the relative phase shift; l - systematic error. In the second measurement, the absolute phase c is fixed at the input of the photodetector 4. with an error d ot,, and at the output of the photodetector 5 - the absolute phase cs / with an error up to. For the relative phase shift in the second dimension we get f o -, + yo ... + a ×. Composing the half-difference of the obtained phases, we find the desired value of the phase shift + LCh + HLP. Thus, the value of the phase shift is obtained without a systematic

the error due to the non-randomness of the photodetectors 4 and 5, which makes it possible to more accurately determine the value of the variable optical delay.

Claims (1)

Due to the presence of a pair of circular polarizers 7 and 8, linear polarizer 13, photodetector 6 and null-organ 16, additional compared to the known device converters 2 and 3, it became possible to combine both the phase calibrator function and the zero device 16 into one device. phase meter functions. In this case, in both modes of operation of the device, the same optical channels are used. In addition to expanding the functional capabilities of the device, it is possible to self-test the device without using external monitoring means, which improves the accuracy of both measurements of the phase-20 log shift and the generation of two oscillations with a predetermined phase shift. Due to the peculiarity of connecting to the channel with the shifted phase of the alternating-25 optical delay and incorporating the mirror 26 into its composition, it became possible to halve the motion of the movable optical delay element. The latter circumstance greatly simplifies, reduces the cost and increases the accuracy of mechanical devices serving the movement of a moving optical delay element. The invention of the Phasometric device containing seven beam splitters, four shutters, six mirrors, three prisms, two photodetectors, a coherent light source and a displacement indicator, which form two optical channels and two optical paths of the self-test, the optical channel of the reference signal containing optically in series the first beam splitter, the first gate, the second beam splitter and the first photodetector connected, the optical channel of the variable phase signal contains successively optically coupled t second beam splitter, a second gate, a fourth CBE todelitel and a second photodetector, and furthermore, the first mirror, a fifth .svetodelitel, peremennuro optical delay moiety consisting of a first (movable) of the prism, a second (fixed) a prism, a second and a third mirror, the latter being mechanically bonded to the first (movable) prism, and the optical delay variable by its third mirror is optically coupled to an interferometric displacement meter consisting of a coherent light source optically coupled to the sixth beam splitter. the fourth mirror and through the sixth beam splitter with a displacement indicator, optical channels are interconnected by two optical self-checking paths, the first self-testing path containing optically coupled to the first beam splitter sequentially optically coupled to the third gate, fourth mirror, third prism, double-sided mirror (first side), which is optically coupled to the fourth beam splitter, the second self-test path contains optically coupled to the third beam splitter, nye fourth valve and a fifth mirror. as well as a double-sided mirror (second side), which is optically coupled to the second splitter, the outputs of the photodetectors are the output terminals of the device, differing in functional capabilities, three sources of modulated optical signal, two mutually orthogonal circular polarizers, an optical wedge and a series of an optically coupled linear polarizer, a third photodetector, and a zero-organ, the linear polarizer being optically coupled via the seventh and fifth beam splitters with both optical the first source of the modulated optical signal is optically connected to the seventh beam splitter, the second source of the modulated optical signal with the second beam splitter, the third source of the modulated optical signal with the fourth beam splitter, is connected to the fifth beam splitter optically through the optical wedge in the optical reference channel and the first circular polarizer, in the optical channel of the variable phase signal, the third beam splitter is optically coupled to the fifth beam splitter through rvoe mirror, a fifth beam splitter optically coupled 9127532210 It is connected with consecutively optical inputs — the inputs of the first, second, and third and second second circular polarizers modulated by the optical torus, the first prism, the second prism, are signal inputs and the second mirror, electrical devices.