Fotomastera pair of optical prisms for laser gyro with a prism of total internal reflection

 

(57) Abstract:

Fotomastera pair of optical prisms for laser gyro with a prism of total internal reflection relates to gyroscopes. Fotomastera pair of optical prisms for laser gyro with a prism of total internal reflection contains the first prism with two refracting faces and one reflecting face of the second prism with input, output, reflecting and mounting faces. There is an optical contact between the mounting face of the second prism and the reflecting face of the first prism out of the field of generation of the laser gyro. The value of the distance from the reflecting face of the first prism to the input face of the second prism varies smoothly from zero from the ribs formed by the installation and the input faces of the second prism, up to three wavelengths at the edges formed by the input and second reflecting faces of the prism. The invention improves the level of accuracy of the laser gyroscope operating in a wide temperature range. 4 Il.

The technical field to which the invention relates.

Laser gyroscope; IPC G 01 C 19/66.

Known fotomastera pair of optical prisms laser gyroscope, which is protot the second resonator of the ring laser and the second prism, having a constant transmittance in the region of the iris radiation and providing hard irised radiation beam, and the second prism is attached to the first adhesive [1]. Under strict irised means is stopped down a beam of laser radiation, in which a small displacement of the beam (about 0.05 mm), or a change in the diameter of the beam corresponds to a significant (about 100%) change in insertion of the diffraction loss. In the temperature range of pereustanovki can reach values of the order of 0.1 mm Hard irised leads to lower precision laser gyroscope in the presence of perestanovok different origin. Adhesive bonding does not provide sufficient mechanical rigidity and strength of the connections, especially over a wide temperature range, which is not constant gap between the first and second prisms, and thus transmittance.

The invention aims to improve the accuracy of the laser gyroscope operating in a wide temperature range, by reducing at least on the order of the steepness of the dependence of the diffraction loss from the input aperture deeper into the field of generation.

the face AD) 4. Prism 5 has a reflective face (face AD) 6 input line 7 and the output line 8. The line 6 is perpendicular to the faces 7 with a small deviation from perpendicularity (1') to form the interference pattern. The faces 6 and 7 form an interference edge. The second prism is attached to the first gap glue out-of-area generation, while on the entrance face of the second prism has a coating that specifies the size of the gap to 3 wavelengths between the input face of the second prism and the reflective face of the first prism. The input line partially overlaps the spot of generation on the reflective face of the first prism. The presence of a small gap leads to the phenomenon of violation of air defense, which is that under the conditions of total internal reflection of the radiation is reflected, however not completely. Due to this phenomenon the input face of the second prism, partially overlapping spot generation on the reflective face of the second prism displays a small (about 0.01%) part of the radiation counter propagating waves radiation of a ring laser, simultaneously performing the function of the iris radiation. Derived from the resonator radiation one of the opposing waves propagated to output the second prism so, that reflected radiation is propagated to the output face of the second prism with a small angle (about 1') relative to the radiation of the first wave. In the plane of the photodetector is thus formed running interference pattern, which then retrieves the parameters of rotation of the gyroscope.

This design work in a wide range of temperatures for the following reasons: significant thermal pereustanovki of the order of 0.1 mm, resulting in change of the diffraction properties photomedicine pair of prisms and the power of the output radiation; unstable properties of the adhesive, leading to instability of the gap between the first and second prism pair, which also changes the diffraction properties of the pair and the power of the output radiation.

All these physical phenomena lead to changes in the difference of the intensities for the oncoming waves. The difference between the intensities leads to additional frequency difference counter will be described with the formula (15.6) from [2]. This frequency difference results in an error, called the shift of the zero laser gyroscope. When perestroika (thermal, mechanical) diffraction conditions are changed differently for the oncoming waves, which leads to additional change inher temperature shift becomes zero variable, which reduces the accuracy of the laser gyro.

To stabilize the shift of the zero of the necessary design photomedicine pair of prisms that is less sensitive to perestroika.

Offer fotomastera pair of prisms shown in Fig. 2. The design introduces the installation face 9 and the second prism is mounted optical contact that faces the reflective face of the first prism. The installation and the entrance face of the second prism to form a mounting edge. The input face of the second prism completely covers the spot of generation, and the size of the gap varies smoothly from 0 at the installation ribs up to 3 (depending on the required transmittance of radiation) wavelength radiation interference ribs. Optical contact between the mounting face of the second prism and the reflecting face of the first prism is an essential characteristic in connection with the fact that in optical contact, first, there is a new property - the intermolecular interaction between the mounting face of the second prism and the reflective face of the first prism; secondly, the reflection coefficient of the reflecting face of the first prism is close to zero in the area of optical contact, which is the basis for selecting seismi.

The proposed design provides the output radiation due to the effect of violation of PVO small (up to 3 wavelengths) variable gap between the pair of prisms. Soft irised is provided by the gradient of the transmittance arising due to the variability of the gap. Under the soft irised means is stopped down, at which a small displacement of the beam or small change in the diameter of the beam corresponds to a small variation of insertion of the diffraction loss. Due to their ability to irised there is no need to specifically enter the aperture, which reduces the diffraction loss and backscatter radiation. The bias stability of the radiation is provided by mounting the prisms hard and durable optical contact.

Thus, the proposed combination of three essential features: the installation face; an optical contact between the mounting face of the second prism and the reflective face of the first prism; a smooth change in the distance from the reflective face of the first prism to the input face of the second prism from zero at the installation faces up to three wavelengths in the interference ribs of the second prism; gives a new property: povyshennogo positive effect.

List of drawings and other materials:

Fig. 1 is a drawing of a prototype photomedicine pair of prisms,

Fig. 2 - drawing of the proposed photomedicine pair of prisms, indicated the relative position of the pair of prisms, the optical axis,

Fig. 3 is a graph showing the distribution of the reflection coefficient of the radiation in the cross-section of the gap,

Fig. 4 is a graph of sensitivity periostracum for the proposed mixing prism and prototype.

Information confirming the possibility of carrying out the invention.

Design photomedicine pair of prisms shown in Fig. 2. In Fig. 3 shows the distribution of the energy reflection coefficient in the cross section in the case of the wedge-shaped gap, i.e. a gap, which gap varies linearly from 0 at the mounting edge of the second prism to 3 wavelengths from the interference of the ribs of the second prism. In Fig. 3 the X-coordinate corresponds to the distance from the middle of the wedge-shaped gap.

The wedge-shaped gap has a variable transmittance in the cross section of the gap.

The energy dependence of the transmittance of the radiation from the gap value is

< / BR>
ik2zd = ;

< / BR>
< / BR>
where - coefficient of skipping the radiation inside the first prism;

1- the dielectric constant of the material of the prisms;

2- the dielectric constant of air;

the wave vector of the radiation in the prisms;

- wavelength radiation.

To acknowledge receipt of the above technical result produced by comparative calculations of sensitivity to perestroika. Sensitivity to perestroika is defined as the ratio of the change of insertion loss to the displacement of the optical beam at thermal perestroika. The results of the calculations are shown in Fig.4 for the prototype and the proposed design. In Fig.4 S - value pereustanovki, A change of insertion loss.

It is obvious that the sensitivity to perestroika significantly lower for the proposed mixing prism.

Literature

1. II St. Petersburg international conference on gyroscopic technology and navigation. H. 1. - St. Petersburg, 1995, S. 125-127.

2. Sager, S., Klimontovich Yu L, Landa P.F. and other Wave and fluctuation processes in lasers/ Ed. by Y. L. Klimontovitch - M.: Nauka, 1974.

Fotomastera pair of optical prisms for laser gyro with a prism of total internal reflection, including PE the tourism contains input, output and reflecting faces, characterized in that the second prism is introduced to an installation face, there is an optical contact between the mounting face of the second prism and the reflecting face of the first prism out of the field of generation of the laser gyro, and the value of the distance from the reflecting face of the first prism to the input face of the second prism varies smoothly from zero at the edges formed by the installation and the input faces of the second prism, up to three waves of radiation fins formed by the input and second reflecting faces of the prism.

 

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