RU195797U1 - Pulsed laser semiconductor emitter - Google Patents

Abstract

The utility model relates to laser technology. A pulsed laser semiconductor emitter contains a base with arrays of laser diodes that are uniformly at an angle to each other around a circle of minimum diameter on a plane perpendicular to the axis of radiation of the emitter, with electrical leads and a sealed enclosure containing a cover with a window and a housing transparent to the radiation of laser diodes. The number of gratings of laser diodes is odd. The Pn junction of each lattice is parallel to the virtual plane drawn through the center of each of them and the center of the base. The base is thermally conductive. The laser diode arrays are electrically connected in series with the correct polarity, and on the reverse side of the base are connected to the output winding of an inserted pulse matching transformer with a transformation coefficient K having a bias winding of the core operating point made of magnetic material with a large saturation induction value. The technical result consists in providing the possibility of obtaining a high uniformity of the radiation intensity with a near-circumferential shape of the contour of the cross section of the radiation pattern with a large pulsed radiation power. 6 ill.

Description

The utility model relates to laser technology, and can be used in industry for organizing open channels for transmitting information, in technology, medicine, pumping systems for solid-state lasers, instrumentation.

The improvement of the characteristics of laser systems is mainly solved by increasing their pulsed radiation power in a narrow spectral range, approximating the radiation pattern (hereinafter referred to as the radiation pattern) of the radiation field of an axisymmetric radiation beam with a circular cross section. At the same time, they solve the problem of reducing the mass of laser emitters, including by eliminating the use of forming optics.

Semiconductor emitters are known (see, for example, [patent RU 141870, B64F 1/18, publ. 06/20/2014], [patent RU 2241287, H01S 5/00, 5/40, publ. 11/27/2004], [patent RU 2187183, H01S 5/00, 5/40, publ. 10.08.2002]).

In the utility model according to patent 141870, the laser modules are evenly spaced around the circumference, each of them is oriented by the large axis of the irradiation spot axisymmetrically in the radial direction and deployed away from the axis of the emitter, in addition, diaphragms are introduced at each laser module to reduce illumination.

In the invention according to patent 2241287, forming optics in a pulsed laser semiconductor emitter is excluded and at least two links of blocks of laser diodes are used. Inside each of the links it is required to accurately withstand, among other things, various pivoting angles of pn junctions of the blocks of laser diodes in both the vertical and horizontal planes of the emitter, which creates great difficulties in assembling these emitters.

The closest in technical essence is the known laser semiconductor injection emitter (see [patent RU 2187183, H01S 5/00]) having a sealed enclosure consisting of a housing with leads and a cover with glass. The blocks of laser diodes are mounted on the plane of the housing, perpendicular to the axis of radiation, around the circumference of the minimum diameter by sequentially turning them relative to each other. According to the above example, “The blocks of laser diodes are evenly spaced around the circle with an angular pitch of 2α, so that the pn junctions of each block 1, 3, 5, 7, 9 are directed to the center of the circle (parallel to the line connecting the center of the laser diode block and the center circles), and the pn junctions of blocks 2, 4, 6, 8, 10 are rotated relative to the direction to the center of the circle at an angle α clockwise around its axis. ”The emitter’s bottom is obtained that is close to round-symmetric (that is, axisymmetric, with a round cross section). In this case, the linear dimensions of the luminescence body, and, consequently, of the entire emitter, were obtained to be minimal; its resistance to external mechanical factors was noted. The emitter of the patent RU 2187183 adopted by us for the prototype.

At the same time, a device with such parameters is not effective enough, low pulse power of the radiation, its insufficient stability, and high heat generation are shown. It has limited control over its parameters.

The technical result of the proposed utility model is to increase the characteristics of laser systems by increasing the pulsed radiation power and improving the uniformity of radiation intensity with the best approximation of the contour of the cross section to the circumference of the radiation pattern (hereinafter NF) of a pulsed laser semiconductor emitter with a narrow spectral range, as well as reducing the average heat generation.

In accordance with the proposed utility model, the technical result is achieved by the fact that a pulsed laser semiconductor emitter (hereinafter referred to as the Emitter) is proposed, comprising a base with laser diode blocks, hereinafter referred to as laser diode arrays (hereinafter RLD), uniformly at an angle to each other around the circumference of the minimum diameter on a plane perpendicular to the axis of radiation of the emitter, with electrical leads and a sealed enclosure containing a cover with a window and a body transparent to the radiation of laser diodes a. Moreover, there is a predominantly odd number of RLDs with p-n junctions of each of them parallel to the virtual plane drawn through the center of each of them and the center of the base. The base is thermally conductive. All RLDs are electrically connected in series with the correct polarity and on the reverse side of the base are connected to the output winding of an inserted pulse matching transformer with a transformation coefficient K having a bias winding of the core operating point, which is a magnetic core made of magnetic material with a large saturation induction value, for example, nanocrystalline metal alloy.

The proposed set of essential features made it possible to create a much more powerful Emitter with a narrow spectral range of radiation, with improved uniformity of radiation intensity with the best approximation of the DN cross section contour to the circle due to the superposition of fields of specifically oriented RLDs of predominantly odd numbers, to which the pump current pulses are not directly applied, and through the original pulse matching transformer with a transformation coefficient of K = 5. At the same time, it was possible to reduce the duration of the pump current pulse and, while maintaining its significant amplitude, increase the length of the supply conductors and reduce their cross-section, and also by increasing the heat generation in the RLD, increase the repetition rate of the RLD pump current pulses. We also obtained the approximation of the contour of the cross section of the DN to the circle with a smaller number of RLDs than in the prototype.

The pulse matching transformer provides the formation of pump current pulses with the required large amplitude, while the amplitude of the current pulses in the primary winding of the matching transformer and the conductors connecting the pulse generator and the matching pulse transformer are K times less than the amplitude of the current pulses flowing through the RLD, which , in turn, allows for the flow of current pulses through the RLD with an amplitude of 140 A - 175 A with a duration of units (3-5) microseconds and thereby reduce the heat generation of the RLD, as well as to increase the maximum intensity of the generated radiation, in comparison with the intensity for pulses of a longer duration of tens to hundreds of microseconds.

In this case, the emitter can be removed from the source of pulses of the pump current, which is especially important if it is necessary to tightly pack the components of the product.

The bias winding serves to set the position of the operating point of the magnetic core of the transformer, which ensures the maximum range of working induction. The use of a core made of a material with a large value of saturation induction (for example, of a nanocrystalline metal alloy) ensures a minimum transformer size, as well as small values of the magnetization currents of the primary and bias windings, which, in turn, contributes to minimal distortion of the shape of the transformed current pulse .

The technical result is also achieved by the fact that

- there is a cylindrical heat-conducting body, while it is possible to use the construction of a square base, square or rectangular case for a number of applications, and for them the entire claimed combination of features will not change.

According to the information available to the authors, the set of essential features characterizing the essence of the claimed invention is unknown and does not follow from the prior art, which allows us to conclude that the utility model meets the criterion of "Novelty". From all the sources of information that we have discovered, the possibility of obtaining the set of features we have proposed does not follow.

The technological implementation of the proposed laser semiconductor injection emitter is based on well-known basic methods for manufacturing a semiconductor emitter and a pulsed matching transformer, which are currently well developed and widely used. The proposal meets the criterion of "Industrial Applicability".

The present invention is illustrated by figures 1-6.

In FIG. 1 a) schematically shows a longitudinal section of the proposed Emitter in accordance with example 1;

b) shows view A on the base with the installed arrays of laser diodes with the cover removed with glass in accordance with Example 1.

In FIG. Figure 2 shows an auxiliary circuit for determining the dependence of the intensity I (ω, α) of the radiation of the Emitter.

In FIG. 3 a) shows the dependence of the intensity I (ω, α) of the radiation of the Emitter in accordance with Example 1 (9 RLD);

b) the radiation pattern of the Emitter is shown in accordance with Example 1 (9 RLD).

In FIG. 4 a) shows the dependence of the intensity I (ω, α) of the radiation of the Emitter in accordance with Example 2 (10 RLD);

b) the radiation pattern of the Emitter is shown in accordance with Example 2 (10 RLD).

In FIG. 5 a) shows the dependence of the intensity I (ω, α) of the radiation of the Emitter in accordance with Example 3 (8 RLD);

b) the radiation pattern of the Emitter is shown in accordance with Example 3 (8 RLD).

In FIG. 6 a) shows the dependence of the intensity I (ω, α) of the radiation of the Emitter in accordance with Example 4 (7 RLD);

b) the radiation pattern of the Emitter is shown in accordance with Example 4 (7 RLD).

The following is a list of the positions indicated on the attached figures (continuous numbering):

1 - Emitter,

2 - the array of laser diodes (hereinafter RLD),

3 - base

4 - the first cover (with a window on the side of the radiation output),

5 - window, transparent to laser radiation,

6 - cylindrical heat-conducting body,

7 - the second cover,

8 - electrical leads of each RLD.

9 - extreme electrical conclusions RLD,

10 - matching pulse transformer,

11 - input external electrical terminals of said transformer,

12 - output electrical contacts of the transformer,

13 - groove for inputting input external electrical terminals of the transformer,

14 - transformer windings,

15 - transformer core,

16 - casting compound

17 - radiation axis of the Emitter,

18 - the first virtual observation plane,

19 - second virtual observation plane.

In the future, the invention is illustrated by specific embodiments of the Emitter. The given examples of modifications are not the only ones and suggest the presence of other implementations.

Example 1. The device of the Emitter 1, schematically depicted in FIG. 1 is characterized by the following. On a flat surface of a copper heat-conducting base 3 around a circle with the same pivot angle θ _n equal to 40 ± 0.25 ° relative to its center, there are nine RLDs 2 with almost identical characteristics of the far-field radiation field, interconnected by electrical leads 8 in series with respect to the polarity, extreme electrical leads 9 are displayed on the back of the base 3.

On the reverse side of the base 3, a matching unit is located centered, which is a pulse matching transformer 10, the output electrical contacts 12 of which are connected to the extreme electrical terminals 9 of the RLD 2. The input electrical terminals 11 of the pulse matching transformer 10 are connected to an external pump circuit - an external short pulse generator current (not shown in the figure), referred to a distance of 50 cm (in other cases, there may be a different distance required and convenient for operation, p Row 30 - 70 cm). On the side of the RLD 2 on the base 3 there is a first cover 4 with a glass exit window 5. On the side of the matching pulse transformer 10, the Emitter 1 is enclosed in a cylindrical heat-conducting housing 6 connected to the base 3 along the perimeter of its side. The cylindrical heat-conducting body 6 is closed from below by a second cover 7 and a groove 13 is made in it for input external electrical leads 11. Between the housing 6, the insulated electrical leads 9, 11, 12 and the pulse matching transformer 11 there is a casting compound 16.

The pulse matching transformer 10 provides, in the load, which consists of a series-connected RLD 2, a large-amplitude current pulse of up to 200 A in duration from 3 to 5 μs, the front and falling of which have a duration of less than 1.5 μs. Such short durations of the rise and fall are ensured by the implementation of a transformer with a transformation coefficient K equal to 5. In this case, the inductance of the conductors 8 connecting the RLD 2 and the output winding of the transformer 10, forming a current path, is less than the leakage inductance of the pulse matching transformer 10 and minimally affects the increase in the duration of the front and the decline of the current pulse flowing in this circuit. In order to minimize the dimensions and mass of the pulse matching transformer 10, as well as to minimize the stray capacitance and dissipation inductance of this transformer 10, a magnetic circuit is used made of a material with a large saturation induction value, for example, a 5T-M TU 14-23-215- nanocrystalline metal alloy 2009. A double increase in the range of variation of the induction, which is achieved by magnetic displacement of the magnetic circuit, serves the same purpose. It is implemented by a magnetic bias winding, to which a low-power electric pulse is supplied before the formation of the pulse of the pump current of the RLD 2. The duration of this pulse must be guaranteed to ensure the formation of the necessary magnetic flux bias. As a result of using a pulsed matching transformer 10, the permissible inductance of the electric line connecting the Radiator 1 and the generator of electric pulses increases by K ² times.

The implementation of short pulses of the pump current RLD 2 reduces the average thermal power emitted by them in the housing 6 of the Radiator 1 and allows increasing their repetition rate while maintaining a high amplitude value of the pump current.

It should be noted that we also tested other grades of nanocrystalline magnetic material for the manufacture of the core (not shown in the figure) of transformer 11. For all other parameters of the Emitter, corresponding to the design of Example 1, no deviations from the results obtained in Example 1 were found.

The emitter 1 operates as follows. At the input of the Emitter 1, i.e. to the primary winding (not shown) of the matching transformer 10, from an external generator of short current pulses (not shown) to the input of the transformer 10 is a pulse signal of high (800 V) voltage and small (30 A) current. Matching pulse transformer 10 with a transformation coefficient K equal to 5 provides the output current pulses with an amplitude of about 150 A with a duration of 4 ± 1 μs at a voltage of 150 V, which determined the minimum distortion of the shape of the transformed current pulse.

To determine the intensity I, rel.units, the radiation of the Emitter, depending on the position of the observer, we proposed using the relation

,

,

where the angular coordinates of the observer are ω and α, denoting

ω, deg. - the angle of rotation of the plane passing through the axis of the Emitter 1, then the observation plane, around the axis of the Emitter 1;

α, city - the angle of inclination relative to the axis of the Emitter 1, namely the angle between the axis of the Emitter 1 and the axis of observation in the observation plane, rotated by an angle ω relative to the "zero" position;

Wx and Wy, hail. - the beam pattern of the RLD 2 at the level of 0.5 from the maximum in the planes perpendicular and parallel to the p-n junction, respectively;

θ _n , rad. - the angle of rotation of the n-th RLD 2 is determined by the formula:

where n is the ordinal number of RLD 2 and N is the total number of RLD 2.

The proposed dependence of the radiation intensity on the angle of rotation ω of the observation plane around the axis of the Emitter 1 at various angles of inclination α of the axis of observation with respect to the axis of the Emitter 1 (the axis of observation at an angle of inclination α ₀ coincides with the axis of the Emitter 1) can be explained using FIG. 2, where the Emitter 1 is shown, the virtual observation planes 17 and 18 and the angular coordinates of the observer are shown — ω and α.

It was previously noted that for this Example 1, the turning angle θ _{n of the} n-th RLD 2 is 40 ± 0.25 °, and the RLD 2 are selected with almost identical characteristics of the far-field radiation field, i.e. deviations of the values of Wx and Wy, deg. are negligible and taken as follows - Wx is 40 ± 2 ° and Wy is 10 ± 1 °. After the calculations, very small changes in the intensity I, rel.units, of the Radiator's radiation were obtained depending on the angle of rotation ω around the axis of the Radiator 1 at various tilt angles α, i.e. depending on the position of the observer (see Fig. 3a). The cross-sectional contour of the radiation pattern of the emitter 1 is close to a circle (see Fig. 3b).

In further examples, the influence of the position of the RLD 2 (change in the angle of rotation θ _n ) and the choice of the number N of the RLD 2 on the radiation patterns of the far field of the Radiator 1 and intensity I, rel. units, radiation of the Emitter 1, depending on the position of the observer.

Example 2. In the second example, the Emitter 1 consists of ten RLD 2 located with the same turning angle θ _n equal to 36 ± 0.25 ° relative to its center. The remaining parameters of the Emitter 1 correspond to the design of Example 1.

The obtained calculated results of the intensity I, rel.ed., emitter radiation depending on the position of the observer are shown in FIG. 4a. Significantly large fluctuations in the intensity value I, rel.ed., which is not acceptable for a number of applications.

The cross-sectional contour of the radiation pattern of the Radiator 1 is close to a circle (see Fig. 4b).

Example 3. In this example, the Emitter 1 consists of eight RLD 2 located with the same turning angle θ _n equal to 45 ± 0.25 ° relative to its center. The remaining parameters of the Emitter 1 correspond to the design of Example 1. A very significant change in the radiation intensity is obtained depending on the angle of rotation ω around the axis of the Emitter 1 for various tilt angles α (see Fig. 5a), which is not acceptable for a number of applications. The cross-sectional contour of the radiation path of the emitter of the Emitter 1 is close to a circle (see Fig. 5b).

Example 4. In this example, the Emitter 1 consists of seven RLD 4 located with the same turning angle θ _n equal to 51.4 ± 0.25 ° relative to its center. The remaining parameters of the Emitter 1 correspond to the design of Example 1. A very insignificant change in the radiation intensity is obtained depending on the angle of rotation ω around the axis of the Emitter 1 at various tilt angles α (see Fig. 6a). The cross section contour of the radiation pattern of the emitter 1 is close to a circle (see Fig. 6b).

It has been shown that it is possible to use various RLD designs, which together make it possible to obtain MDs with a section contour close to the circumference and almost uniform intensity I, rel. units, emitter radiation depending on the position of the observer was obtained only when using an odd number of RLD.

Differences in the contours of the cross sections of the beam pattern from the circumference in different directions are explained both by the scatter of the spatial characteristics of the used laser structures and by defects in the manufacturing technology of the RLD and the assembly of the Emitters.

The above studies showed an improved uniformity of the radiation intensity of the Emitter with a circular cross-sectional shape of the bottom beam of a pulsed laser semiconductor emitter, at an increased repetition rate of current pulses that are transformed to RLD with minimal distortion in the shape of the pulses, which determined the obtained high pulsed radiation power of the Emitter in a narrow spectral range.

Claims (1)

A pulsed laser semiconductor emitter comprising a base with blocks of laser diodes, hereinafter referred to as laser diode arrays, uniformly at an angle to each other along a circle of a minimum diameter on a plane perpendicular to the axis of radiation of the emitter, with electrical leads and a sealed sheath containing a cover with a transparent for radiation laser diodes with a window and a housing, characterized in that there is an odd number of laser diode arrays with pn junctions of each of them parallel to the virtual plate The bones drawn through the center of each of them and the center of the base, the base is thermally conductive, all the arrays of the laser diodes are electrically connected in series with the correct polarity, and on the reverse side of the base are connected to the output winding of the introduced pulse matching transformer with a transformation coefficient K having a bias winding of the core operating point made of a magnetic material with a large amount of saturation induction, for example, a nanocrystalline metal alloy.

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