SU1727096A1 - Beam splitter with power division ratio of 1:20 - Google Patents

Abstract

The invention relates to optical elements based on multilayer interference coatings and can be used in instrument making, laser technology, and the like. The purpose of the invention is to expand the functionality by the single-beam nature of power sharing, simplifying the manufacturing process and reducing the degree of polarization. The beam splitter consists of a substrate with a refractive gap of 1.48-1.55, on both sides of which three-layer interference coatings are applied. On one side, the coating is made dividing with refractive indices and optical thicknesses of layers equal to, counted from the substrate, respectively, mon 1.37-1.39, pa 1.90-2.00, mon 1.37-1.39 and Ai / 4, Ai / 4, Ai / 4, where AI (1,112-1,124) AO. On the other side, the coating is made enlightening with refractive indices and optical thicknesses of layers equal to, calculated from the substrate, respectively n. 1.62, clauses 1.90-2.00, mon 1.37-1.39 and A2 / 4.A2 / 2, A2 / 4, whereA2 (1.280-1.293) AO, whereAo is the wavelength of the radiation incident to the beam splitter . 2 Il. (Ls

Description

The invention relates to optical elements based on multilayer interference coatings and can be used in instrument making, laser technology, and the like.

The purpose of the invention is to expand the functionality by the single-beam nature of power sharing, simplifying the manufacturing process and reducing the degree of polarization.

FIG. 1 shows the proposed beam splitter; in fig. 2 shows its spectral characteristic.

The design of the splitter with a 1:20 power division ratio is practically implemented by applying. In vacuum

separating and antireflection coatings in the URM.3.279.060 vacuum deposition unit on two sides of a flat substrate of K8 optical glass with dimensions of 6x8x1 mm. The manufactured beam splitter was designed to operate at an angle of incidence of radiation of 45 ° in the wavelength range centered on the AO 850 nm. The separation coating was made on the basis of three alternating layers of MgFa and Zr02, and the MDP2 films were deposited first on the substrate. All three layers of the divider coating had an optical thickness of Ai / 4, where Ai is 945-955 nm. The antireflection coating was made on the basis of AlO3, Zr02, and MgF2 films, and the films were deposited on

Xi

yu vj

oh oh

the substrate first, and the MgF2 films were bordered by air. The optical thickness of А 20ziMdP2 films was equal to A2 / 4, Zr02 A2 / 2 films. Here, A2 1088-1099 nm.

At a deposition temperature of 150 ° C, the MgF2, A120z, and Zr02 films had refractive indices of 1.38, 1.61, and 1.95, respectively. The experimental transmission spectra of S- and P-polarization of radiation incident at a 45 ° angle to the thus created splitter are shown in FIG. 2. Measurements were made on an SF-26 spectrophotometer using a crystal polarizer in the form of a Plan prism. From FIG. 2 it follows that in the wavelength range of 780–930 nm (Ts + Tp) / 2 95.2 ± 1%, i.e. the divider with good accuracy divides the power of the radiation incident on it in the ratio of 1:20. In this case, the degree of polarization of the radiation transmitted through the beam splitter does not exceed 1%. Thus, a non-proportional beam splitter with a power division ratio P: T of 1:20 is manufactured, operating in a fairly wide range of wavelengths centered on the AO 850 nm. The divider design, which contains a separating coating on one side of the flat substrate and an antireflection coating on the other, provides a single-beam division: the division of power in the required ratio occurs on the surface of the separating coating. This beam splitter operating in the spectral range of 780-950 nm can be used to divide the radiation power with a central wavelength of 850 nm from both a laser source having a spectral width of 10 nm and an LED having a spectral width of 100 nm. Such light-emitting diodes and semiconductor lasers are widely used in fiber-optic communication lines and related test equipment.

The benefits of using a splitter are as follows:

The beam splitter has a wider working wavelength range (i.e., the wavelength range in which the division ratio is 1:20 and the degree of polarization is small) YES (0.93-1.03) 10, where L is the central working wavelength range.

The single-cycle nature of power sharing allows the divider to expand the functionality, namely:

- implement the divider design on substrates of any thickness;

- use a divider to split the power in photodetectors with arbitrary sizes of the photosensitivity of the region,

- use a divider to split the power into the integrated optical and optical fibers, as well as other

dividers and lenses.

Simplified manufacturing technology divider.

For the manufacture of the divider, it is necessary to apply only six to the flat substrate.

layers.

The degree of polarization of the divider decreases.

The beam splitter in a wide spectral range YES (0.90-1.10) AO degree

Claims (1)

polarization in the transmitted beam Pt S 2%. and in the reflected beam PR 25%. The invention: A splitter with a power division ratio of 1:20, consisting of a plane-parallel substrate with a refractive index of 1.46-1.55 with coatings applied on both sides, characterized in that, in order to extend the functionality by the single-beam nature of power division , simplify the manufacturing process and reduce the degree of polarization, the coating on one side of the substrate is made of a three-layer dividing with indicators refractions and optical thicknesses of layers, equal, counted from the substrate, respectively, mon 1.37-1.39, pic 1.90-2.00, mon - 1.37-1.39 and Ai / 4, Ai / 2, Ai / 4, where Ai (1,112-1,124) AO, on the other-side of the three-layer antireflection optical depth of layers with refractive indices, equal from the substrate, respectively mon 1.60-1.62, p 1.90-2, 00, mon 1.37-1.39 and A2 / 4, A2 / 4, A2 / 4, where A2 (1,280-1,293) AO, and the AO is equal to the wavelength of radiation incident on the beam splitter. Pv-1.90 + 2.00 ,, 39- -ZW-- // 4  / /, // // 0 / // ///  X # # / # & , /, / # # # # # jЈ / / ft ft WO + 2.00 / r H 1,, 39 % wm Ag№ Jonm g / g Jonm  Lag / 4 TsJp fo Vup-2 150 80Q 850 900 2 j 950 L, w