CN221898749U - Phase modulation factor measuring device of PZT optical fiber phase modulator - Google Patents

Abstract

The utility model discloses a phase modulation coefficient measuring device of a PZT optical fiber phase modulator, comprising a laser, an M-Z interferometer, a triangular wave driving source for applying voltage to the optical fiber phase modulator in the M-Z interferometer to change the length of the optical fiber, a photoelectric detector for detecting the light intensity change of the light output by the M-Z interferometer, and an oscilloscope for displaying the light intensity change waveform. The utility model applies a triangular wave driving voltage to the PZT optical fiber phase modulator on one arm of the M-Z interferometer, so that the intensity of the interference light at the interference point of the two arms changes linearly with the increase of the voltage, and the phase modulation coefficient at the interference point can be quickly and accurately calculated according to the light intensity of the sine wave seen on the oscilloscope.

Description

A phase modulation coefficient measurement device for a PZT optical fiber phase modulator

Technical Field

The utility model relates to the technical field of optical fiber communication, in particular to a phase modulation coefficient measuring device of a PZT optical fiber phase modulator.

Background Art

Fiber optic interferometers have been widely used in the field of sensing and measurement due to their anti-electromagnetic interference, electrical insulation, high sensitivity, wide range of measurement objects, light weight, and small size. Among them, fiber optic phase sensors that use phase as the measured physical quantity have the advantages of high precision and large dynamic range, and are widely used in measuring pressure, temperature, displacement, electromagnetic field, acoustic field, etc. Therefore, in the sensors composed of these fiber optic interferometers, the measurement of phase is crucial. Among the commonly used detection technologies, piezoelectric ceramic (PZT) phase modulators are widely used. It can be used in fiber optic interferometers to compensate for external environmental disturbances to improve stability; it can also be used in superheterodyne interference systems to perform sensitive and linear detection of optical phase shifts. Therefore, the determination of piezoelectric ceramic phase shift parameters is the key. Nowadays, there are two main methods for measuring the phase shift parameters of piezoelectric ceramics. One is to perform theoretical analysis based on the stress-strain relationship of elastic materials based on the theory of elasticity, and obtain the theoretical relationship between the voltage value of the piezoelectric ceramic and the phase change of the optical signal in the optical fiber; the other is to use the output light intensity of the fiber optic interferometer to judge the phase difference between the two interference arms, thereby determining the phase shift coefficient of the piezoelectric ceramic. However, these two methods are cumbersome to operate, and the measurement stability is insufficient and the measurement accuracy is not high.

Summary of the invention

In view of this, the utility model provides a phase modulation coefficient measurement device for a PZT optical fiber phase modulator, so as to solve the problems existing in the above-mentioned background technology.

A phase modulation coefficient measuring device for a PZT optical fiber phase modulator comprises a laser, an M-Z interferometer, a triangular wave driving source for applying voltage to the optical fiber phase modulator in the M-Z interferometer to change the length of the optical fiber, a photoelectric detector for detecting the intensity change of light output by the M-Z interferometer, and an oscilloscope for displaying the waveform of the intensity change, wherein the output end of the laser is connected to the input end of the M-Z interferometer, the output end of the M-Z interferometer is connected to the input end of the photoelectric detector, and the output end of the photoelectric detector is connected to the input end of the oscilloscope.

Preferably, the M-Z interferometer includes a first optical splitter, a second optical splitter and a PZT optical fiber phase modulator, the input end of the first optical splitter is connected to the output end of the laser, one splitter arm of the first optical splitter is connected to the input end of the second optical splitter, and the other splitter arm is connected to the input end of the PZT optical fiber phase modulator, the output end of the PZT optical fiber phase modulator is connected to one splitter arm of the second optical splitter, the light emitted by the laser is divided into two paths through the first optical splitter, one of which is directly transmitted to the second optical splitter, and the other is transmitted to the second optical splitter through the PZT optical fiber phase modulator, and the two split light beams generate light interference at the coupling point of the two arms of the second optical splitter.

Preferably, the first optical splitter and the second optical splitter are both 1×2 optical splitters with equal splitting ratios.

Preferably, the laser is a narrow linewidth laser.

Preferably, the light intensity variation waveform displayed on the oscilloscope is a sine wave.

The beneficial effects of the utility model are:

The utility model applies a triangular wave driving voltage to a PZT optical fiber phase modulator on one arm of an M-Z interferometer, so that the intensity of interference light at the interference point of the two arms changes linearly with the increase of voltage. The phase modulation coefficient at the interference point can be calculated quickly and accurately according to the light intensity of a sinusoidal wave seen on an oscilloscope, and the measurement fluctuation error can also be reduced, thereby improving the measurement accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

FIG1 is a schematic diagram of the structure of a phase modulation coefficient measurement device.

FIG. 2 is a schematic diagram of a sine wave waveform displayed by an oscilloscope.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is described below by specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the utility model. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the utility model.

The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. The singular forms of "a", "said" and "the" used in this disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and/or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

It should be understood that although the terms first, second, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms and should not be understood as indicating or implying relative importance. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of the present disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information.

In order to better understand the technical solution of the present invention, the present invention is described in detail below with reference to the accompanying drawings.

The utility model provides a phase modulation coefficient measuring device of a PZT optical fiber phase modulator, comprising a laser, an M-Z interferometer, a triangular wave driving source for applying voltage to the optical fiber phase modulator in the M-Z interferometer to change the length of the optical fiber, a photoelectric detector for detecting the light intensity change of the light output by the M-Z interferometer, and an oscilloscope for displaying the light intensity change waveform, wherein the output end of the laser is connected to the input end of the M-Z interferometer, the output end of the M-Z interferometer is connected to the input end of the photoelectric detector, and the output end of the photoelectric detector is connected to the input end of the oscilloscope.

Preferably, the M-Z interferometer comprises a first optical splitter, a second optical splitter and a PZT fiber phase modulator, the input end of the first optical splitter is connected to the output end of the laser, one optical splitter arm of the first optical splitter is connected to the input end of the second optical splitter, the other optical splitter arm is connected to the input end of the PZT fiber phase modulator, and the output end of the PZT fiber phase modulator is connected to one optical splitter arm of the second optical splitter. The light emitted by the laser is divided into two paths through the first optical splitter, one of which is directly transmitted to the second optical splitter, and the other is transmitted to the second optical splitter through the PZT fiber phase modulator, and the two split light beams generate light interference at the coupling of the two arms of the second optical splitter.

When the optical path difference between the two arms of the M-Z interferometer changes, the intensity of the light interference also changes. The change of the light intensity output by connecting a photodetector to the splitter arm of the second optical splitter is measured. When a triangular wave driving source is applied to the PZT fiber phase modulator, the light intensity detected by the photodetector changes with the linear increase of the voltage. Therefore, the light intensity is seen as a sine wave in the oscilloscope class. The two peaks (or two valleys) of the sine wave indicate that the phase amplitude of the PZT fiber phase modulator at this time is 2π. At this time, the driving voltage difference corresponding to the two times is U, and the phase modulation coefficient is 2π/U radians. The fluctuation error of the measurement can be reduced by measuring multiple peaks (or valleys). As shown in Figure 2, one channel in the figure is a triangular wave, and the other channel is a sine wave of the phase information detected by the interferometer. The voltage difference corresponding to 2π×3 shown in the figure is 297.5mV, so the phase modulation coefficient can be calculated.

In this embodiment, the laser is a narrow linewidth laser, the first optical splitter and the second optical splitter are both 1×2 optical splitters with equal splitting ratios, and the oscilloscope is a multi-channel oscilloscope.

It should be clear that the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

Claims (5)

1. A phase modulation coefficient measuring device for a PZT optical fiber phase modulator, characterized in that it comprises a laser, an M-Z interferometer, a triangular wave driving source for applying voltage to the optical fiber phase modulator in the M-Z interferometer to change the optical fiber length, a photoelectric detector for detecting the intensity change of light output by the M-Z interferometer, and an oscilloscope for displaying the waveform of the light intensity change, wherein the output end of the laser is connected to the input end of the M-Z interferometer, the output end of the M-Z interferometer is connected to the input end of the photoelectric detector, and the output end of the photoelectric detector is connected to the input end of the oscilloscope. 2. The phase modulation coefficient measuring device of the PZT optical fiber phase modulator according to claim 1 is characterized in that the M-Z interferometer comprises a first optical splitter, a second optical splitter and a PZT optical fiber phase modulator, the input end of the first optical splitter is connected to the output end of the laser, one splitter arm of the first optical splitter is connected to the input end of the second optical splitter, and the other splitter arm is connected to the input end of the PZT optical fiber phase modulator, the output end of the PZT optical fiber phase modulator is connected to one splitter arm of the second optical splitter, the light emitted by the laser is divided into two paths through the first optical splitter, one path of light is directly transmitted to the second optical splitter, and the other path of light is transmitted to the second optical splitter through the PZT optical fiber phase modulator, and the two split light beams generate light interference at the coupling point of the two arms of the second optical splitter. 3 . The phase modulation coefficient measuring device of the PZT optical fiber phase modulator according to claim 2 , wherein the first optical splitter and the second optical splitter are both 1×2 optical splitters with equal splitting ratios. 4 . The phase modulation coefficient measuring device of the PZT optical fiber phase modulator according to claim 1 , wherein the laser is a narrow linewidth laser. 5 . The phase modulation coefficient measuring device of the PZT optical fiber phase modulator according to claim 1 , wherein the light intensity variation waveform displayed on the oscilloscope is a sine wave.