RU2597941C2 - Optical amplifier head with diode pumping (versions) - Google Patents

Abstract

FIELD: optics.

SUBSTANCE: invention relates to laser engineering. Diode pumped optical amplifier head comprises encased: an active element in form of a rod, matrix of laser diodes arranged regularly on holders, and cooling system containing tube encircling the active element to make a circular channel δ, channels arranged in the housing and each holder, inlet, outlet branch pipes and made in the housing inlet and outlet manifolds, tube is made from material transparent for pumping radiation. Cooling system is in form of a single contour, and the housing of the optical amplifier head is composed of cylinder.

EFFECT: technical result consists in possible reduction of hydraulic resistance of the cooling system.

5 cl, 8 dwg

Description

The invention relates to diode-pumped solid-state lasers, in particular to pump elements and their cooling systems, and can be used in the manufacture of laser technology.

Known optical amplification head (OUG) with diode pumping, consisting of placed in the housing of the active element (AE) in the form of a rod, matrix of laser diodes (MLD) located on the holders, and a cooling system (CO) containing a tube covering the AE with the formation annular channel, and channels located in the housing and holders, with inlet and outlet pipes. The channels are also located in the MLD, which are made in the form of blocks of rulers of laser diodes and are located at an angle of 90 ° to the axis of the AE. The device is equipped with damping elements mounted on both ends of the tube, gaskets are used as damping elements (US patent No. 6101208, H01S 3/0941, 1997).

In this device, the cooling of the AE and MLD occurs due to the high flow rate of the coolant (coolant). Maintaining a constant coolant temperature allows you to extend the life of the MLD and to provide constant and stable output parameters of the exhaust gas.

However, uneven and incomplete filling of the AE pump radiation leads to the formation of inhomogeneous excitation regions, the appearance of thermomechanical stresses inside the AE, which can lead to its failure. The uneven filling of the AE pump radiation also leads to a decrease in the pump efficiency. The location of the cooling channels in the matrices of laser diodes is not optimal, since the distance from the MLD to the cooling channels is not minimal, as a result of which the efficiency of heat removal from the heated surface of the MLD decreases. This can lead to a decrease in the quality of MLD cooling and a decrease in the energy stored in the inverse population.

The closest analogue of the claimed invention, selected as a prototype, is a diode-pumped COG, consisting of a rod located in the AE body, MLD located uniformly on the holders and facing the AE by the emitting region, and a CO containing a tube covering the AE to form ring channel δ, channels located in the housing and each holder, inlet and outlet pipes and made in the housing of the inlet and outlet manifolds, from which channels connected to the rotary channels exit holders located in holes made on the outer surface of the housing, the tube is made of a material transparent to pump radiation (RF patent No. 2498467, IPC H01S 3/0933, 3/042, publ. 2013).

The location of the MLD evenly around the AE makes it possible to uniformly fill the AE with pump radiation, which reduces the thermal stresses in it and also increases the pump efficiency. The implementation of CO from two independent cooling circuits allows you to independently adjust and maintain the optimum temperature for MLD and AE.

However, the presence of two cooling circuits requires either the presence of two external CO or one external CO and an external device for distributing coolant flows between the circuits, which leads to a complication of the cooling circuit of the exhaust gas. The use of MLD with cooling channels of a small cross section and, in particular, their series connection leads to an increase in the hydraulic resistance of the OGG. When using AE with a small diameter (compared with the width of the MLD radiating region), a significant part of the pump radiation will not get into it, and a significant part of the pump radiation that gets into it will not be absorbed. This will lead to a decrease in the efficiency of delivery of pump radiation to the AE and, as a result, to a decrease in the energy stored in the inverse population. And also an OUG with two cooling circuits contains a large number of parts and has large dimensions and mass.

The problem to which the invention is directed is to increase the efficiency of the OUG, as well as reduce the size and weight.

The technical result obtained by using the proposed technical solution is to reduce the hydraulic resistance of CO, simplify the cooling scheme, increase the energy stored in the inverse population.

The essence of the first option lies in the fact that in an OGD with diode pumping, consisting of: AE in the form of a rod, MLD located uniformly on the holders and facing the AE by the emitting region, and CO containing a tube surrounding the AE with the formation of an annular channel δ, the channels located in the housing and each holder, the inlet and outlet nozzles and the inlet and outlet manifolds made in the housing, from which the channels connected to the rotary channels made in the holders located in the holes exit, made On the outer surface of the casing, the tube is made of a material transparent for pump radiation, the feature is that the CO is made in the form of a single circuit and contains a choke with channels installed between the input collector and the annular channel, connected to the input and output nozzles of the input and output additional collectors located in one of the holders, and channels made in the housing and connecting the input and output collectors with additional input and output collectors, the diameter of catch exceeds the diameter of the holders channels throttle inlet manifold channels connect to an annular channel which is connected to the outlet manifold, additional input and output are connected to the collectors of the holder channel, and the housing is formed as a cylinder.

The whole set of these features ensures the optimal mode of operation of the OAG. This was achieved due to the following: for cooling the AE and MLD, one external cooling circuit is used, to match the hydraulic resistance of the cooling channel of the AE with the hydraulic resistance of the cooling channels of the MLD, a choke is used in the cooling circuit; the holes in the throttle are evenly distributed around the circumference, which allows to obtain a uniform coolant flow along the AE; the diameter of the rotary channels exceeds the diameter of the main channels of the holders; holders assumed the function of MLD heat exchangers. Thus, a decrease in the hydraulic resistance of CO is achieved with a simplification of the cooling scheme, as well as an increase in the energy stored in the inverse population, and the problem of increasing the efficiency of the CVG with a decrease in the dimensions and mass of the entire structure is solved.

The essence of the second embodiment of the invention lies in the fact that in an OGC with diode pumping, consisting of: AE in the form of a rod, MLD located uniformly on the holders and facing the AE by the emitting region, and CO containing a tube covering the AE with the formation of a ring channel δ, channels located in the housing and each holder, inlet and outlet pipes and made in the housing of the input and output manifolds, from which channels connected to the rotary channels made in holders placed in the hole On the outer surface of the casing, the tube is made of a material transparent for pump radiation, the feature is that the ends of the AE are fixed in the clamps installed in the casing, the CO is made in the form of a single circuit and contains channels made in the clamps, the input and output additional collectors formed by clamps, a tube and AE, and channels made in the housing and connecting the input and output nozzles to the input and output collectors that are connected to the clamp channels, while the diameter is tnyh channels exceeds the channel diameter holders holders, clamps channels connected to the additional inlet and outlet manifolds which are connected to the annular channel, and the housing is formed as a cylinder.

The principle of operation of the OAC in the second embodiment is similar to the operation of the OCA in the first embodiment. And the technical result achieved in this case is the same as when implementing the device according to the first embodiment. To increase the energy stored in the inverse population, the OGG can be equipped with reflectors placed opposite each MLD installed in the openings of the housing on the holders.

To increase the energy stored in the inverse population, each MLD can be equipped with a lens mounted on the MLD surface facing the AE.

When conducting analysis of the prior art, including a search by patent and scientific and technical sources of information, and identifying sources containing information about analogues of the claimed invention, no analogues were found that are characterized by features that are identical to all the essential features of this invention. The definition from the list of identified analogues of the prototype as the closest in the set of essential features of the analogue, allowed to identify the set of essential distinguishing features from the prototype set forth in the claims.

Therefore, the claimed invention meets the condition of "novelty."

To verify the conformity of the claimed invention with the condition "inventive step", the applicant conducted an additional search for known solutions in order to identify signs that match the distinctive features of the claimed device from the prototype. As a result of the search, no technical solutions with these characteristics were identified. On this basis, we can conclude that the claimed invention meets the condition of "inventive step".

In FIG. 1 shows a longitudinal section of the OGG in the first embodiment.

In FIG. 2 shows a transverse section of the OGG according to the first embodiment.

In FIG. 3 shows the throttle.

In FIG. 4 shows a transverse section of the OGG in the first embodiment with lenses.

In FIG. 5 shows a longitudinal section of the OGG according to the second embodiment.

In FIG. 6 is a cross-sectional view of the OGG to the second embodiment.

In FIG. 7 shows a section aa in FIG. 5.

In FIG. 8 is a transverse section of an OGG in a second embodiment with lenses and reflectors.

The diode-pumped COG according to the first embodiment (Fig. 1-3) contains a housing 1 made in the form of a hollow cylinder, in which AE 2 is installed in the form of a rod, the ends of which are fixed in clamps 3, 4 installed in the housing. Holes (not shown) are made on the outer surface of the housing 1 to accommodate the holders 5 of the MLD 6. The MLD 6 is located uniformly on the surface of the housing 1 and faces the AE by the radiating region.

СО ОУГ is made in the form of a single circuit for cooling AE and MLD. CO contains a tube 7, covering AE 2 with the formation of an annular channel δ, input and output pipes 8, 9 and input and output headers 10, as well as additional input and output headers 11, a choke 12 and channels a, b, c, d, e located in the housing 1, the holders 5 and the inductor 12 (Fig. 3). The tube 7 is made of a material transparent to pump radiation (for example: glass, fused quartz, leucosapphire, etc.). The outer diameter and thickness of the tube are calculated based on the required focusing of the pump radiation. The annular channel δ forms a coolant layer cooling the AE.

The inductor 12 is installed between the input manifold 10 and the annular channel δ. The channels from the inductor 12 connect the input collector 10 to the annular channel δ, which in turn is connected to the output collector 10.

Additional input and output collectors 11 are located in one of the holders 5 and are connected to the input and output pipes 8, 9. Between themselves, additional collectors 11 are connected by the channel b of the holder.

The remaining holders 5 are provided with rotary channels e, connected to the channels b of the holders and channels d of the housing 1, emerging from the input and output headers 10. Moreover, the diameter of the rotary channels e exceeds the diameter of the channels b of the holders 5.

CO contains channels a made in the housing 1, which connect the input and output collectors 10 with additional input and output collectors 11.

The tube 7 is installed in the housing using the clip 13.

Each MLD 6 can be equipped with a lens 14 mounted on the surface of the MLD facing AE 2 (Fig. 4).

The diode-pumped COG according to the second embodiment (Fig. 5-7) contains a housing 1 made in the form of a hollow cylinder, in which AE 2 is installed in the form of a rod, the ends of which are fixed in clamps 4, 15 installed in the housing 1. On the outer surface of the housing 1, holes (not shown) are made to accommodate holders 5 of the MLD 6, which are uniformly located on the surface of the body and face the radiating region to AE 2.

СО ОУГ is made in the form of a single circuit for cooling AE and MLD. CO contains a tube 7, covering AE 2 with the formation of an annular channel δ, input and output pipes 8, 9 and input and output headers 10, as well as additional input and output headers 16 and cooling channels b, d, e, f, g, located in the housing 1, clamps 15 and holders 5. The tube 7 is made of a material transparent to pump radiation (for example: glass, fused quartz, leucosapphire, etc.). The outer diameter and thickness of the tube are calculated based on the required focusing of the pump radiation. The annular channel δ forms a coolant layer cooling the AE. The inlet and outlet pipes 8, 9, due to the presence of free space between the holders 5, are located directly on the housing 1. This allows you to reduce the hydraulic resistance of the OGG and simplify its design (compared with the first option).

The tube 7 is installed in the housing using clamps 15.

Additional input and output collectors 16 are formed by clamps 15, tube 7 and AE 2. Channels g of clamps 15 are connected to input and output collectors 10 and to additional input and output collectors 16 (Fig. 7), which in turn are connected to the annular channel δ . Clips 15 with channels g allow more accurate distribution of coolant flows between the cooling channels of the MLD and AE, and also do not have a mechanical effect on the AE (in comparison with the inductor 12 in the design according to the first embodiment).

Holders 5 MLD 6 are equipped with rotary channels e, connected to the channels b of the holders and channels d of the housing 1, emerging from the input and output headers 10 of the housing. The diameter of the rotary channels e exceeds the diameter of the channels b of the holders 5.

The cooling circuit contains channels f made in the housing 1, which connect the inlet and outlet manifolds 10 to the inlet and outlet pipes 8, 9.

Each MLD 6 can be equipped with a lens 14 mounted on the surface of the MLD 6 facing AE 2 (Fig. 8). The OUG can be equipped with reflectors 17 installed in the holes of the housing 1 on the holders 18, and placed opposite each MLD 6.

The device according to the first embodiment works as follows. The supply voltage is supplied to the MLD 6, the MLD 6 begin to generate pump radiation, which, passing through the tube 7 and the coolant of the annular channel δ, is absorbed by AE 2, where part of the absorbed pump energy is used for heat loss. In continuous operation, the heat dissipation power is quite high, so cooling of AE 2 is required. In MLD 6, part of the electric energy is spent on heat losses, so they also need to be cooled. Cooling AE and MLD is as follows.

The coolant is supplied through the inlet pipe 8 to the OGG and enters the additional input manifold 11. Then the coolant is divided into two streams - the first enters the channel b of holder 5, passing through which it cools the MLD 6, and enters the output additional collector 11, and the second stream, passing through the channel a of the housing, it enters the input manifold 10.

In the intake manifold 10, the coolant is divided into two flows - the first cools the AE 2 and the second MLD 6. The quantitative ratio between these two flows of coolant is determined by the hydraulic resistance of the channels from the inductor 12.

The first coolant stream from the intake manifold 10 through the channels from the inductor 12 enters the annular channel δ and passes along the AE 2, in contact with its surface and cools it. Passing along AE 2, the coolant at its opposite end enters the output manifold 10 and through the housing channel a to the additional output manifold 11, then through the outlet pipe 9 it is withdrawn from the OUG.

The second coolant stream from the inlet manifold 10 through channels d made in the housing 1 enters the rotary channels e of the holders, passes through the channels b of the holders, entering the output of the similar rotary channels e and through channels d, the output manifold 10, channels a and the output additional collector 11 is output from the optical amplifier head. The coolant, passing through the channels b of the holders 5, cools the MLD.

For additional focusing of the pump radiation (increase in efficiency), lenses 14 are used (Fig. 4).

The device according to the second embodiment works as follows. The supply voltage is supplied to the MLD 6, the MLD begin to generate pump radiation, which, passing through the tube 7 and the coolant of the annular channel δ, is absorbed by AE 2, where part of the absorbed pump energy is used for heat loss. In continuous operation, the heat dissipation power is quite high, so cooling of AE 2 is required. In MLD 6, part of the electric energy is spent on heat losses, so they also need to be cooled. Cooling AE and MLD is as follows.

The coolant is supplied through the inlet pipe 8 to the exhaust gas and flows through the channel f of the housing 1 to the input manifold 10. Then, the coolant is divided into two streams - the first enters the channels g of clamp 15 and the second enters the channels of holders 5. The quantitative ratio between these two coolant streams is set by the hydraulic resistance of the channels g of the clamp 15.

From channels g of clamp 15, through an additional input collector 16, the coolant enters the annular channel δ of cooling AE 2. Passing along the AE 2, the coolant contacts its surface and cools it. Having passed along AE 2, the coolant at its opposite end enters the output additional collector 16 and through the channels g of the clamp 15 to the output collector 10, from where it passes through the channels f of the casing to the output pipe 9 and is discharged from the CVC.

The second stream from the input manifold 10 through the channels d of the housing 1 enters the rotary channels e of the holders 5, passes through the channels b of the holders, reaching the outlet of the similar rotary channels e and through the channels d of the housing, the output manifold 10 and channels f are removed from the OGG through the output pipe 9. The coolant, passing through the channels b of the holders 5, cools the MLD 6.

For additional focusing of the pump radiation (increase in efficiency), lenses 14 can be used (Fig. 8).

A portion of the pump radiation not absorbed in the AE 2 and transmitted through it can be returned back by the reflectors 17 (Fig. 8). The profile of the reflected pump radiation is determined by the shape of the reflective surface of the reflectors 17 and the tube 7.

Thus, the data presented indicate that when using the claimed invention, the following combination of conditions:

- a tool embodying the claimed device in its implementation, is intended for use in the electronic and optical-mechanical industry in the manufacture of devices with high power for medicine, technology and other purposes;

- for the claimed device in the form in which it is described in the claims, the possibility of its implementation is confirmed.

Therefore, the claimed invention meets the condition of "industrial applicability".

Claims (5)

1. Optical amplification head with diode pumping, consisting of an active element in the form of a rod, arrays of laser diodes arranged uniformly on the holders and facing the active element with a radiating region, and a cooling system containing a tube enclosing the active element with the formation of a ring channel δ, channels located in the housing and each holder, inlet and outlet pipes and made in the housing inlet and outlet manifolds, from which channels connected to the rotary channels lamellas made in holders placed in holes made on the outer surface of the housing, the tube is made of a material transparent to pump radiation, characterized in that the cooling system is made in the form of a single circuit and contains a choke with channels installed between the input collector and the annular channel additional collectors connected to the input and output nozzles of the input and output placed in one of the holders, and channels made in the housing and connecting the input and output collectors to additional input and output collectors, the diameter of the rotary channels exceeds the diameter of the channels of the holders, the throttle channels connect the input collector to the annular channel, which is connected to the output collector, additional input and output collectors are connected by the holder channel, and the body is made in the form of a cylinder. 2. The optical amplifier head according to claim 1, characterized in that each matrix of laser diodes is equipped with a lens mounted on the surface of the matrix facing the active element. 3. Optical amplification head with diode pumping, consisting of: an active element in the form of a rod, arrays of laser diodes arranged uniformly on the holders and facing the active element with a radiating region, and a cooling system containing a tube enclosing the active element with the formation of a ring channel δ, channels located in the housing and each holder, inlet and outlet pipes and made in the housing inlet and outlet manifolds, from which channels connected to the rotary channels lamellas made in holders placed in holes made on the outer surface of the casing, the tube is made of a material transparent for pump radiation, characterized in that the ends of the active element are fixed in the clamps installed in the casing, the cooling system is made in the form of a single circuit and contains channels made in the clamps, input and output additional collectors formed by clamps, a tube and an active element, and channels made in the housing and connecting the input and output pipes to the input and outlet manifolds which are connected to rams channels, wherein the diameter exceeds the diameter of the rotary channel holders channels clamps channels connected to the additional inlet and outlet manifolds which are connected to the annular channel, and the housing is formed as a cylinder. 4. The optical amplifier head according to claim 3, characterized in that each matrix of laser diodes is equipped with a lens mounted on the surface of the matrix facing the active element. 5. The optical amplifier head according to claim 3, characterized in that it is equipped with reflectors placed opposite each matrix of laser diodes, mounted in the holes of the housing on the holders.

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