JP2876176B2 - Method of manufacturing waveguide glass laser - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a waveguide glass laser using glass as a light emitting base material.

[0002]

2. Description of the Related Art As a laser using glass as a light emitting base material including a light emitting medium, a light emitting base material is formed into a cylindrical shape, and a waveguide structure is formed by a core having a light emitting medium added thereto and a clad glass having a lower refractive index than the core. Glass fiber lasers and glass fiber amplifiers. Some of these waveguide glass lasers exhibit superior characteristics as compared with semiconductor lasers, and some of them are being put to practical use for application as long-distance optical communication devices.

[0003] Quartz glass and fluoride glass are mainly used as the light-emitting base glass material of these lasers. It has been developed based on. That is, in the case of quartz glass,
A method of forming a luminescent base glass to which a luminescent medium is added by combining a method called liquid immersion with VAD or MCVD (herein, called a gas-liquid immersion method) is used. As an example, a core soot (glass fine particles) is prepared using the VAD method, is impregnated with an alcohol solution containing a rare earth element halide as a luminescent medium, is sintered to form a core rod, and a clad soot is formed on the core rod. A glass preform is formed by sintering, from which a glass fiber is spun to produce a laser.

On the other hand, in the case of fluoride glass, a multi-component melt of metal fluoride is prepared for the core and the clad, and then the clad melt is poured into the mold and the outside of the clad melt which contacts the mold is solidified. After a certain period of time when the central part is still in the molten state, the part in the molten state is removed from the mold, and the core glass melt is poured into the space formed at that time and cooled, and the glass preform is cooled. To form At this time, a rare earth element fluoride as a light emitting medium is simultaneously melted in the core glass melt to form a glass laser preform in which the light emitting medium is added to the core (referred to herein as a simultaneous melt method). From this, a glass fiber is spun to produce a waveguide glass laser.

[0005]

However, taking a fluoride glass as an example, a glass having excellent transmission properties as a bulk glass, such as a ZnF ₂ -GaF ₃ -InF ₃ -PbF ₂ glass or a P glass
In spite of bF ₂ -AlF ₃ -based glass, a waveguide glass laser using the glass as a glass light-emitting base material could not be produced in the above-mentioned conventional technology. This is because a conventional waveguide glass laser manufacturing method cannot manufacture a waveguide glass laser unless it is made of a part of fluoride glass having particularly excellent glass stability. This is because glass systems with low stability could not be targeted. That is, the conventional method can target only a few systems which are particularly easy to vitrify among the fluoride glasses.

A description will be given of how glass stability is an important key in a conventional fluoride waveguide glass laser manufacturing process. In the conventional waveguide glass laser manufacturing process, the problem of glass stability is that the glass melt cooling process in the first stage glass preform process and the reheating process of the cladding glass near the core-cladding glass interface And in the reheating process in the second stage fiber spinning process.

[0007] When discussing glass stability, there are two indices: crystallization onset temperature _Tx and glass transition temperature _Tg.
ΔT = T _x −T _g and the critical cooling rate.
In general, the crystal growth rate and the nucleation rate have a temperature dependency such that they become maximum near the crystallization start temperature and the glass transition temperature, respectively. Therefore, the difference ΔT = T _x −T _g between the crystallization onset temperature and the glass transition temperature corresponds to the degree of overlap between the crystal growth rate and the nucleation rate as shown as a function of temperature. In other words, when ΔT is large, the degree of overlap between the two becomes small, and it is difficult for crystals to appear, indicating that the glass stability is high. The critical cooling rate is the minimum value of the cooling rate at which the glass melt can be cooled to produce glass free of crystals.The smaller this value is, the faster the glass can be vitrified without rapid cooling. It indicates that the property is high.

[0010] From the viewpoint of the two indices described above, when discussing a glass system to which the conventional waveguide glass laser manufacturing method can be applied, the conventional manufacturing method is limited to a glass system having a low critical cooling rate and a large ΔT. . Critical cooling rates have been reported for some fluoride glass compositions and range from 0.7 to 370 K / min. ZrF4-HfF4-BaF2-LaF3-A
The lF3-NaF glass has a minimum value of 0.7 K / min and exhibits extremely excellent stability. In practical examples of producing a waveguide glass laser by a conventional method, a ZrF ₄ -HfF ₄ -BaF ₂ -LaF ₃ -AlF ₃ -NaF glass is used as a glass base material in most cases. For exceptional glass stability.

On the other hand, there is no data on the critical cooling rate of the ZnF ₂ -GaF ₃ -InF ₃ -PbF ₂ system glass, but ΔT is 40-60 K, and ZrF ₄ -HfF ₄ -BaF ₂ -LaF _3- In AlF ₃ -NaF glass
It is much smaller than 90K. In fact, ZnF ₂ -GaF _3-
In the case of InF ₃ -PbF ₂ glass, glass can be produced using a method of pouring a glass melt into a mold and quenching only in a non-waveguide structure in which the reheating process of the glass is not a problem. A glass preform with a structure cannot be made. Further, the PbF ₂ -AlF ₃ system glass can be vitrified only by using a special production method capable of obtaining a very high cooling rate, and even in that case, only a thin ribbon glass can be obtained.

[0010] As described above, in the waveguide type glass laser produced by the conventional technique, the glass base material that can be used is limited to ZrF ₄ -HfF ₄ -BaF ₂ -LaF ₃ -AlF ₃ -NaF glass. I was Z which has a longer infrared transmission wavelength range than this glass system
Despite the known existence of nF ₂ -GaF ₃ -InF ₃ -PbF ₂ glass system and PbF ₂ -AlF ₃ glass system, it is difficult to produce lasers of these glass systems by conventional technology from the viewpoint of glass stability. Was impossible from Further, there is no disclosure of a technique relating to a waveguide type glass laser manufacturing method using a glass system having a low stability as a light emitting base material.

The above description has been made on the problems in the method of manufacturing the waveguide type fluoride glass laser. Here, the drawbacks in the prior art are summarized as follows. (1) The material of the luminescent base material is SiO ₂ / GeO ₂
In addition, the simultaneous melt method is limited to a multi-component metal fluoride system which becomes a glass by quenching from the melt, and other glasses cannot be used as a luminescent base material, and the luminescent base material glass is selected. The degree of freedom was extremely small. (2) Since the electron level of the light-emitting medium is affected by the electron-ligand interaction, the light-emitting characteristics change depending on the type of the light-emitting base material. Therefore, a technique of improving the light emission characteristics by changing the type of the light emitting base material is generally used in this field. However, there is a limit in the improvement of the light emission characteristics due to the small degree of freedom in selecting the light emitting base glass according to (1). (3) The maximum wavelength of the transmission wavelength range of quartz glass and fluoride glass that can be used as a luminescent base glass is limited to about 2 μm and 3.6 μm, respectively. for that reason,
The emission wavelength range of the laser is also limited, and it has been difficult to produce a laser having a wavelength range exceeding this range. (4) Regardless of quartz glass or fluoride glass, the shape of the luminescent base material produced by the above method was limited to a columnar shape, and other waveguide structures could not be taken.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the above-mentioned disadvantages of the prior art and to manufacture a waveguide glass laser capable of taking a waveguide structure other than a columnar shape without limiting the kind of glass material usable as a light emitting base material. It is an object of the present invention to provide a method for manufacturing a waveguide glass laser.

[0013]

In order to achieve this object, the present invention relates to a physical vapor deposition method such as a sputtering method, a vacuum vapor deposition method (electron beam vapor deposition method, resistance heating vapor deposition method), a molecular beam vapor deposition method or the like. Uses thin film preparation method classified as chemical vapor deposition method as a means of preparing glass thin film and means of adding luminescent medium instead of vapor-liquid immersion method and simultaneous melt method, and has selective etching method or specific pattern on the surface A waveguide glass laser is produced by using a method of pressing a flat plate against a thin film and transferring the pattern as a glass thin film processing means for setting an optical waveguide structure. Furthermore, the clad thin film and the core glass thin film are made of a fluoride glass composed of at least one of GaF ₃ and InF ₃ and ZnF ₂ and PbF ₂ or a fluoride glass composed of PbF ₂ and AlF ₃ to be red. A waveguide glass laser in the outer region is manufactured.

[0014]

According to the manufacturing method of the present invention, the types of glass materials that can be used as a luminescent base material can be greatly expanded.
The degree of freedom in selecting the light emitting base glass can be greatly increased. This also means that the characteristics of the laser can be improved by optimizing the luminescent base glass, and the transmission wavelength region of the glass can be extended to a longer wavelength side particularly in the infrared region. Therefore, it is possible to manufacture a waveguide type glass laser in the infrared region extending to the longer wavelength side, which cannot be realized by the conventional technology. According to this manufacturing method, a glass thin-film multilayer structure can be obtained according to the shape of the substrate. Therefore, by selecting the shape of the substrate, a laser having a shape other than the columnar shape can be manufactured. As a result, the present invention has the above disadvantages (1) to (4).
This problem can be solved.

[0015]

EXAMPLE An example of a method for manufacturing a ridge-type waveguide glass laser will be described. Example 1 A lower clad glass thin film was formed on a semiconductor substrate, a groove was formed in the thin film by selective etching, and a core glass thin film containing a luminescent medium and an upper clad glass thin film were formed. One example of manufacturing a corrugated glass laser. An example of a method of manufacturing a thin film waveguide glass laser which is a fluoride glass material that can be vitrified by a simultaneous melt method, which is a conventional technique, but cannot be manufactured by a conventional technique. Is shown in FIG. First, a fluoride glass for lower cladding glass, for example, 40% ZrF ₄ -13 is formed on a GaAs (100) substrate 1.
_{% HfF 4 -20% BaF 2 -4} % LaF 3 a -3% AlF ₃ -20% NaF to target to form a lower clad glass film 2 having a thickness of 10μm by sputtering for example magnetron sputtering [1 (A). Next, a SiN thin film is deposited on the clad glass thin film by a plasma CVD method, and a window having a width of 20 μm is formed by a normal photoetching process to form a selective etching mask 4. ZrOC
l ₂ The clad glass film is selectively etched to -HCl based etchant as selective etchant, to form a groove depth of 2μm [FIG 1 (b)]. Next, the SiN selective etching mask is removed with a hydrofluoric acid-based etchant. Thereafter, on the lower clad thin film 3 in which the groove is formed, a fluoride glass for a core, for example, 53% ZrF ₄ -20% BaF ₂ -4% LaF ₃ -3% Al, to which Tm is added as a light emitting medium by using a magnetron sputtering method.
F ₃ -20% NaF and fluoride glass for upper cladding glass, for example 40% ZrF ₄ -13% HfF ₄ -20% BaF ₂ -4% LaF ₃ -3% AlF ₃ -20% NaF
8 μm thick core thin film 5
And an upper clad thin film 6 having a thickness of 10 μm [FIG.
(C)]. Next, the GaAs substrate is polished to a thickness of 150 μm, and a flattened glass multilayer film end face without unevenness is formed by a cleavage operation. After that, one end face has 0
An optical film having a reflectance close to 100% with respect to the laser oscillation light, and an optical film having an appropriate reflectance with respect to the pump light at 100% with respect to the excitation light, such as an electron It is deposited by a beam evaporation method. As a result, length 10cm width 1
A waveguide glass laser having a ridge waveguide structure with a waveguide width of 20 μm in cm can be manufactured. In this laser, for example, a waveguide type glass laser that oscillates at a wavelength of 2.31 nm when a light emitting region of the core thin film 5 is excited in a direction perpendicular to the paper surface by a laser beam having a wavelength of 670 nm can be obtained. -Can be used as a high light-collecting and coherent light source.

Example 2 A stripe-shaped projection having a convex cross section in a state in which a lower clad glass thin film is formed on a semiconductor substrate, and then the lower clad glass is heated to a temperature near the glass softening temperature of the lower clad glass. A groove is formed by pressing a metal plate (with a convex stripe-shaped projection) against the lower clad glass thin film, and a waveguide glass laser is formed by forming a core glass thin film containing a luminescent medium and an upper clad glass thin film. FIG. 2 shows an embodiment of a method of manufacturing a waveguide type glass laser which is a fluoride glass material which can be vitrified by a simultaneous melt method which is a conventional technique but cannot be manufactured by a conventional technique. . Fluoride glass for lower cladding glass such as 40% ZrF ₄ -13% Hf on GaAs (100) substrate 1
Using a sputtering method such as a magnetron sputtering method, a lower clad glass thin film 2 having a thickness of 10 μm is formed using F ₄ -20% BaF ₂ -4% LaF ₃ -3% AlF ₃ -20% NaF as a target [FIG. a)]. Next, while the lower clad glass thin film is heated to near the glass softening temperature of the lower clad glass, the Ni flat plate 7 having a convex stripe-shaped projection having a width of 20 m and a step of 2 μm on the surface is pressed against the lower clad glass thin film and then removed. As a result, a groove having a width of 20 μm and a step of 2 μm is formed as a replica of the Ni flat plate on the surface of the lower clad glass thin film [FIG. 2 (b)]. Thereafter, on the lower clad thin film 2 in which the groove is formed, a fluoride glass for a core to which Er is added as a light emitting medium using a magnetron sputtering method, for example, 53% ZrF ₄ -20% BaF ₂ -4% LaF ₃ -3% AlF ₃ -20% NaF
And fluoride glass for upper cladding glass, e.g. 40% Zr
Targeting at F ₄ -13% HfF ₄ -20% BaF ₂ -4% LaF ₃ -3% AlF ₃ -20% NaF, a core glass thin film 5 having a thickness of 8 μm and an upper clad glass thin film 6 having a thickness of 10 μm are provided. Is precipitated [FIG. 2 (c)]. Next, the GaAs substrate is polished to a thickness of 150 μm, and a flattened glass multilayer film end face having no irregularities is formed by a GaAs cleavage operation. Then, on one end face, an optical film having a reflectance of 0% with respect to the excitation light and near 100% with respect to the laser oscillation light, and on the other end face with 100% with respect to the excitation light with respect to the laser light. An optical film having an appropriate reflectance is deposited by, for example, an electron beam evaporation method. As a result, the length is 10cm,
A waveguide glass laser having a ridge-type waveguide structure having a width of 1 cm and a waveguide width of 20 μm can be manufactured. In this laser, for example, if the light emitting region of the core thin film 5 is excited in a direction perpendicular to the paper surface by a laser beam having a wavelength of 790 nm, a waveguide type glass laser oscillating at a wavelength of 2.75 nm can be obtained . It can be used as a light source with high brightness, high light collection and coherence.

Embodiment 3 A lower clad glass thin film and a core glass thin film containing a light-emitting medium are formed on a semiconductor substrate, and a convex stripe-shaped projection is formed on the core glass thin film by a selective etching method.
Furthermore, in one embodiment of manufacturing a waveguide glass laser by forming an upper clad glass thin film, a waveguide glass laser using a fluoride glass material as a light emitting base material which cannot be vitrified by the simultaneous melting method which is a conventional technique. FIG. 3 shows an example of the method for manufacturing the above. On a GaAs (100) substrate 1, fluoride glass for lower cladding glass 22% ZnF ₂ -32% using molecular beam method
Lower clad glass thin film 2 having a thickness of 10 μm using ZnF ₂ , GaF ₃ , and PbF ₂ which are constituents of GaF ₃ -46% PbF ₂ as a molecular beam source.
And fluoride glass for core glass 20% ZnF ₂ -32% Ga
F ₃ -48% PbF ₂ constituents ZnF ₂ , GaF ₃ , PbF ₂ and ErF ₃ added as a luminescent medium are used as molecular beam sources and have a thickness of 8
A μm core thin film 8 is formed (FIG. 3A). next,
A Ti thin film is deposited on the clad glass thin film by an electron beam evaporation method, and a stripe having a width of 20 μm is formed by a normal photo-etching process to form a selective etching mask 9. The cored glass thin film is selectively etched by a sputtering etching method to form a convex stripe-shaped projection having a step of 2 μm (FIG. 3B). Next, the Ti selective etching mask is removed by a reactive ion etching method. Thereafter, on the core glass thin film 10 on which the convex protrusions are formed, fluoride glass for upper clad glass 22% using a molecular beam method.
ZnF ₂ -32% GaF ₃ -46% PbF ₂ constituents ZnF ₂ , GaF ₃ , P
10 μm thick upper clad thin film using bF ₂ as molecular beam source
11 is deposited [FIG. 3 (c)]. Next, the GaAs substrate is polished to a thickness of 150 μm, and a flattened glass multilayer film end face without unevenness is formed by a cleavage operation. Then, on one end face, an optical film having a reflectance of 0% with respect to the excitation light and near 100% with respect to the laser oscillation light, and on the other end face with 100% with respect to the excitation light with respect to the laser light. An optical film having a suitable reflectance is deposited by, for example, an electron beam evaporation method. As a result, a waveguide glass laser having a ridge-type waveguide structure having a length of 10 cm, a width of 1 cm, and a waveguide width of 20 μm and using a ZnF ₂ -GaF ₃ -PbF ₂ system glass as a light emitting base glass can be manufactured. . In this laser, for example, if the light emitting region of the core glass thin film 10 is excited in a direction perpendicular to the paper surface by a laser beam having a wavelength of 655 nm, a waveguide type glass laser oscillating at a wavelength of 3.50 μm can be obtained . It can be used as a high-brightness, high-concentration, coherent light source. A waveguide glass laser using a luminescent medium of ErF ₃ can be realized by a conventional manufacturing method using a ZrF ₄ —BaF ₂ —LaF ₃ —AlF ₃ —NaF-based glass as a luminescent base material. However, the infrared transmission wavelength range is up to 3.6 μm in this glass system, whereas it is 9 μm in ZnF ₂ -GaF ₃ -PbF ₂ system glass.
Since the length of the light-emitting base material extends down to μm, the loss value of the light-emitting base material at the oscillation wavelength of 3.50 μm is smaller in the latter case, and a laser having a smaller oscillation threshold value can be obtained.

[Embodiment 4] A lower clad glass thin film and a core glass thin film containing a light-emitting medium are formed on a semiconductor substrate, and then a groove is formed in a state where the core glass thin film is heated to a temperature near the glass softening temperature of the core glass. An example of manufacturing a waveguide type glass laser by forming a convex stripe-shaped projection on the surface of the core glass thin film by pressing a metal plate against the core glass thin film, and further forming an upper clad glass thin film, according to the prior art FIG. 4 shows an embodiment of a method for producing a waveguide type glass laser using a fluoride glass material which cannot be vitrified by the simultaneous melt method as a light emitting base material. Fluoride glass for lower cladding glass 70% on GaAs (100) substrate 1 using electron beam evaporation
Using PbF ₂ and AlF ₃ , which are constituents of PbF ₂ -30% AlF ₃ , as a deposition source, a lower clad glass thin film 2 having a thickness of 10 μm and a fluoride glass 73% PbF ₂ -27% AlF ₃ for core glass The core thin film 8 having a thickness of 8 μm is formed using PbF ₂ and AlF _{3 as} constituent components and DyF ₃ added as a light emitting medium as an evaporation source [FIG. 4 (a)]. Next, with the core glass thin film heated near the glass softening temperature of the core glass, the width is 20 μm and the depth is 2 μm.
The Ni flat plate 12 having a groove of m on the surface is pressed against the lower clad glass thin film and then removed to form a convex stripe-shaped projection having a width of 20 μm and a step of 2 μm as a replica of the Ni flat plate on the surface of the core glass thin film [FIG. (B)]. afterwards,
PbF which is a component of fluoride glass 70% PbF ₂ -30% AlF ₃ for upper clad glass using electron beam evaporation on the core glass thin film 10 on which the convex stripe-shaped protrusions are formed
_2. An upper clad glass thin film 11 having a thickness of 10 μm is deposited using AlF ₃ as an evaporation source [FIG. 4 (c)]. Next, GaAs
The substrate is polished to a thickness of 150 μm, and a flattened glass multilayer film end face with no unevenness is formed by GaAs cleavage. afterwards,
One end face has an optical film having a reflectance of 0% for the excitation light and a reflectance close to 100% for the laser oscillation light, and the other end face has an appropriate optical film for the 100% laser light with respect to the excitation light. An optical film having a reflectance is deposited by, for example, an electron beam evaporation method. As a result, a waveguide glass laser having a ridge waveguide structure having a length of 10 cm, a width of 1 cm and a waveguide width of 20 μm can be manufactured. In this laser, the core glass thin film 10
Of if the excitation in the direction perpendicular to the light-emitting region on paper in a wavelength 1.73 [mu] m of the laser beam and can be guided type glass laser oscillating at a wavelength of 4.34 [mu] m, infrared high intensity and high light-harvesting-Friendly It can be used as a coherent light source. In the conventional method of manufacturing a waveguide glass laser, glass that can be used as a light emitting base material is ZrF ₄ -BaF ₂ -LaF _{3-with an} infrared transmission wavelength range up to 3.6 μm.
Since it was an AlF ₃ —NaF-based glass, it was not possible to produce a glass laser outside the infrared transmission wavelength range of this glass as in this example. Only by applying the manufacturing method according to the present invention, the waveguide type PbF ₂ -Al which cannot be realized by the conventional manufacturing method
It could be fabricated F ₃ based glass laser, wavelength 4.34 mu
It is possible to oscillate at m.

Example 5 A lower clad glass thin film and a core glass thin film containing a luminescent medium are formed on a semiconductor substrate, and then the core glass thin film is heated to a temperature near the glass softening temperature of the core glass to form a double layer. Pressing a metal plate with convex stripe-shaped projections against the core glass thin film to form a double groove in the surface of the core glass thin film, and then forming a waveguide glass laser by forming an upper clad glass thin film FIG. 5 shows an embodiment of a method of manufacturing a waveguide glass laser using a fluoride glass material, which cannot be vitrified by the conventional simultaneous melting method, as a light emitting base material. On a GaAs (100) substrate 1, a fluoride glass 22% ZnF ₂ for lower cladding glass is formed by a sputtering method such as a magnetron sputtering method.
-32% GaF ₃ -46% PbF ₂ target and 10μm-thick lower clad glass thin film 2 and core fluoride glass doped with HoF ₃ as luminous medium 20% ZnF ₂ -32% GaF ₃ -48% An 8 μm-thick core thin film 14 is formed by using PbF ₂ as a target (FIG. 5A). Next, with the core glass thin film heated near the glass softening temperature of the core glass, a double convex protrusion having 20 μm wide and 2 μm step-like convex stripe-shaped protrusions arranged at intervals of 20 μm is formed on the surface. Pressing the Ni flat plate 13 against the lower clad glass thin film and removing it, the width of the Ni flat plate as a replica of the Ni flat plate on the surface of the core glass thin film
A double groove having grooves of 20 μm and steps of 2 μm arranged at an interval of 20 μm is formed [FIG. 5 (a)]. Thereafter, fluoride glass 22% ZnF ₂ for upper clad glass was formed on the core glass thin film 14 having the double groove formed thereon by magnetron sputtering.
An upper clad glass thin film 15 having a thickness of 10 μm is deposited using -32% GaF ₃ -46% PbF ₂ as a target (FIG. 5B).
Next, the GaAs substrate is polished to a thickness of 150 μm, and a flattened glass multilayer film end face having no irregularities is formed by a GaAs cleavage operation. Then, on one end face, an optical film having a reflectance of 0% with respect to the excitation light and near 100% with respect to the laser oscillation light, and on the other end face with 100% with respect to the excitation light with respect to the laser light. An optical film having a suitable reflectance is deposited by, for example, an electron beam evaporation method. As a result, a waveguide glass laser having a ridge-type waveguide structure having a length of 10 cm, a width of 1 cm and a waveguide width of 20 μm can be manufactured. In this laser,
When the light emitting region of the core glass thin film 14 is excited in a direction perpendicular to the paper surface by, for example, a laser beam having a wavelength of 640 nm, a wavelength of 2.89 μm
, And can be used as a high-brightness, high-concentration, coherent light source in the infrared region.

Next, an embodiment of a method of manufacturing a buried type waveguide glass laser will be described.

Embodiment 6 A lower clad glass thin film and a core glass thin film containing a light emitting medium are formed on a semiconductor substrate, and then the core glass thin film is processed into a rectangular shape by a selective etching method. An example of manufacturing a waveguide glass laser by forming a waveguide glass laser using a fluoride glass material as a light-emitting base material that cannot be vitrified by a simultaneous melt method as a conventional technique. Is shown in FIG. GaAs
(100) On the substrate 1, a fluoride glass for the lower clad glass, for example, 22% ZnF ₂ -16% InF ₃ -16% GaF ₃ -46% Pb, using a sputtering method, for example, a magnetron sputtering method.
A 10 μm-thick lower clad glass thin film 2 targeting F _2, and a fluoride glass for a core doped with Er, Tm, Ho, and Dy as a light-emitting medium, for example, 20% ZnF ₂ -16% InF ₃
An 8 μm-thick core glass thin film 8 is formed using -16% GaF ₃ -48% PbF ₂ as a target (FIG. 6A). Next, Ti
The thin film is deposited on the core glass thin film by an electron beam evaporation method, and a stripe having a width of 20 μm is formed on the Ti thin film by a usual photo etching process.
And Next, the core glass thin film is selectively etched by a sputter etching method to form a square shape having a width of 20 μm and a height of 10 μm (FIG. 6B). Next, the Ti selective etching mask 9 is removed by a reactive ion etching method.
Then, fluoride glass for upper clad glass, for example, 22% ZnF ₂ -16% InF ₃ -16%, is formed on the core glass thin film 16 processed into a square shape and the exposed lower clad glass thin film 2 by magnetron sputtering. An upper clad thin film 17 having a thickness of 20 μm is deposited using GaF ₃ -46% PbF ₂ as a target (FIG. 6C). Next, the GaAs substrate is polished to a thickness of 150 μm, and the flattened glass multilayer film end face without unevenness is formed by a cleavage operation. Then, on one end face, an optical film having a reflectance of 0% with respect to the excitation light and near 100% with respect to the laser oscillation light, and on the other end face with 100% with respect to the excitation light with respect to the laser light. An optical film having a suitable reflectance is deposited by, for example, an electron beam evaporation method. As a result, a waveguide glass laser having a buried waveguide structure having a length of 10 cm, a width of 1 cm, and a waveguide width of 20 μm can be manufactured. In this laser, when the light emission region of the core glass thin film 16 is excited in a direction perpendicular to the paper surface with laser light having a wavelength of, for example, 640 nm, 647 nm, 790 nm, or 1.73 μm, the wavelength is 2.31 μm,
[mu] m, 2.88 [mu] m, can be guided type glass laser which oscillates at 4.34 [mu] m, a high luminance and high light-collecting in the infrared region,
As a coherent light source, for example, it can be used as a light source of an infrared branching analyzer. In the conventional manufacturing method of a waveguide glass laser, the glass that can be used as a light emitting base material is an infrared transmission wavelength range of 3.6 μm.
Since this was a ZrF4-BaF2-LaF3-AlF3-NaF-based glass, it was not possible to produce a glass laser having an oscillation wavelength outside the infrared transmission wavelength range of this glass as in this example. Only by applying the manufacturing method according to the present invention, the waveguide type ZnF ₂ -InF ₃ -GaF ₃ -PbF _{2 which} cannot be realized by the conventional manufacturing method
System glass laser can be manufactured, oscillation wavelength 4.34
It is possible to manufacture a multi-wavelength oscillation glass laser including μm.

Example 7 A lower clad glass thin film and a core glass thin film containing a light emitting medium are formed on a semiconductor substrate, and then the core glass thin film is processed into a square by a selective etching method. In this embodiment, which is different from Embodiment 6 in which a waveguide glass laser is manufactured by forming the waveguide glass laser, a waveguide glass laser in which a fluoride glass material which cannot be vitrified by the conventional simultaneous melting method is used as a light emitting base material. FIG. 7 shows an embodiment of a method of manufacturing a waveguide glass laser having a structure for improving the coupling efficiency with the semiconductor laser for exciting the waveguide glass laser and the emission light of the waveguide glass laser. Shown in On a GaAs (100) substrate 1, the molecular beam source was used as a molecular beam source, using PbF ₂ and AlF ₃ , which are constituents of 70% PbF ₂ -30% AlF ₃ , a fluoride glass for the lower cladding glass, using a molecular beam method. 10μm
The lower clad glass thin film 2 is made of PbF ₂ and AlF ₃ which are constituents of 73% PbF ₂ -27% AlF ₃ of fluoride glass for the core.
Then, a core glass thin film 19 having a thickness of 8 μm is formed using HoF ₃ added as a light emitting medium as a molecular beam source [FIG.
(A)]. Next, a Ti thin film is deposited on the clad glass thin film by an electron beam evaporation method, and as shown in FIG. 8, one width is set to the light emitting layer width (for example, 100 μm) of the semiconductor laser for excitation.
And the other width is adjusted to the core diameter of the output fiber (for example,
10 μm), and a taper stripe having a tapered shape between them is formed on the Ti thin film by a normal photo-etching process to form a glass etching mask 18. Then, by a sputtering etching method is selectively etched co Aga Las film 19 changes therebetween width tapered other end in the way the shape of one end has a width 100μm height 10μm is in rectangular shape of width 10μm height 10μm [FIG. 7
(A) (b)]. Next, the Ti selective etching mask is removed by a reactive ion etching method. Then, on the core glass thin film 19 processed into a square shape and the exposed lower clad glass thin film 2, using a molecular beam method, fluoride glass 70% PbF ₂ -30% AlF ₃ for upper clad glass is used. Using a certain PbF or AlF ₃ as a molecular beam source, an upper clad thin film 20 having a thickness of 30 μm is deposited (FIGS. 7C and 7D).
Next, the GaAs substrate is polished to a thickness of 150 μm, and a flattened glass multilayer film end face without unevenness is formed by a cleavage operation.
Then, on one end face, an optical film with a reflectance of 0% for the excitation light and near 100% for the laser oscillation light, and on the other end face, a 100% for the excitation light An optical film having a suitable reflectance is deposited by, for example, an electron beam evaporation method. As a result, it is possible to manufacture a waveguide glass laser having a buried waveguide structure having a length of 10 cm and a width of 1 cm and capable of increasing the coupling efficiency with the excitation laser and the emission fiber. In this laser, the core glass thin film 19
Is excited in the direction perpendicular to the plane of the page by laser light with wavelengths of 640 nm, 647 nm, and 790 nm, for example, at wavelengths of 2.31 μm and 2.70 μm.
It can be a waveguide glass laser that oscillates at μm and 2.88 μm, and can be used as a light source for high-brightness, high-concentration, and coherent light in the infrared region, for example, as a light source for an infrared branching analyzer.

In the above embodiment, the sputtering method, the molecular beam method, the vacuum evaporation method (electron beam evaporation method,
Although the description is limited to the physical vapor deposition method (resistance heating method), other physical vapor deposition methods such as ionized vapor deposition method, high-frequency induction heating method, reactive vapor deposition method, arc vapor deposition method, laser vapor deposition method, and other vacuum vapor deposition methods are also described. It is feasible. Furthermore, CVD method, MOCVD
It can also be performed by a chemical deposition method such as a plasma CVD method.

In the above embodiment, the substrate material is described as a GaAs semiconductor substrate.
The present invention is also applicable to a P, GaSb semiconductor substrate. Further, the substrate material can be arbitrarily selected according to the purpose, as long as it can be used by a physical vapor deposition method or a chemical deposition method without being limited to a semiconductor substrate.

In the above embodiment, ZrF4-HfF4-BaF2-LaF3-AlF3-NaF, ZnF ₂ -InF ₃ -GaF _3-
PbF ₂ based composition other than the composition have been described only in fluoride glass of PbF ₂ -alF ₃ system described in Example, also be carried out with a fluoride glass composed of a combination of a metal fluoride other than these combinations it can. In addition, halide glass,
Chalcogenide glass, oxide glass, or any other material that can be produced by physical vapor deposition or chemical deposition can be used.

In the above embodiment, the shape of the thin film is described as a simple groove / convex / square for the sake of simplicity. However, any structure may be used as long as light is guided. Whatever shape is equivalent as long as it is equivalent in wave theory, for example, a deformed shape from a simple shape or a complex shape obtained by modifying a simple shape may be used.

Further, the thickness, width,
The numerical values related to the groove depth, the length of the convex step, etc. and the width of the selective etching mask and the width of the Ni metal plate, the groove depth, the length of the convex step, etc. are limited to these. Not
It only has to correspond to the numerical value regarding the length of the waveguide structure calculated based on the optical waveguide theory.

[0028]

According to the present invention, the type of the luminescent base glass can be greatly expanded as compared with the lasers manufactured by the conventional gas-liquid immersion method or the simultaneous melting method. The degree of freedom in selecting glass can be greatly increased. This also means that the characteristics of the laser can be improved by optimizing the luminescent base glass, and the transmission wavelength region of the glass can be extended to a longer wavelength side particularly in the infrared region. Therefore, it is possible to manufacture a waveguide type glass laser in the infrared region extending to the longer wavelength side, which cannot be realized by the conventional technology. According to this manufacturing method, a glass thin-film multilayer structure can be formed according to the shape of the substrate, so that a laser having a shape other than the columnar shape can be manufactured by selecting the shape of the substrate.

The inventions according to claims 3 and 4 of the present application are directed to an exposure apparatus for photo etching and an apparatus for forming an etching mask thin film required for a selective etching method, for example, plasma CVD.
It has the effect of not requiring expensive equipment such as an apparatus, and can reduce the complicated steps such as the etching mask thin film forming step, the photo etching step, and the etching mask forming step in the selective etching method into a single step of pressing a flat plate. effective.

According to a fifth aspect of the present invention, there is provided a semiconductor device comprising: ZnF ₂ -InF ₃ -GaF
_Since the infrared transmission wavelength range of the glass light-emitting base material can be extended to 9 μm by using _3- PbF ₂ glass as a glass thin film material, a waveguide glass laser in the infrared region extending to the longer wavelength side is manufactured. There is an effect that can be.

[0031] The present invention of claim 6, since it is possible to extend the PbF ₂ -alF ₃ based glass to 18μm infrared transmission wavelength range of the glass emitting base material by the glass thin film material, the length
There is an effect that a waveguide glass laser in the far infrared region extending to the wavelength side can be manufactured.

When a semiconductor substrate is used in the present invention, an end face which can be used as a laser resonator without polishing a glass multilayer film laminated on the substrate is formed by utilizing the cleavage characteristics of the semiconductor substrate. There is an effect that can be done.

In the present invention, when a method of forming a glass thin film using a sputtering method is used, the luminescent base glass itself can be used as a vapor deposition source. The thin film manufacturing method is more efficient than the thin film manufacturing method.

In the present invention, when a method of forming a glass thin film by using a vacuum evaporation method is used, since a constituent material of a luminescent base glass is used as an evaporation source, a thin film preparation in a case where production of the glass itself is difficult. Not only can it be used as a method, but also there is an effect that it can be used as an efficient thin film manufacturing method when the process of manufacturing glass itself is complicated and time-consuming.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a method of manufacturing a glass light emitting device having a ridge-type waveguide structure in which a groove and a convex stripe-shaped protrusion are formed by using a selective etching method according to the present invention and a waveguide structure is formed. .

FIG. 2 is a cross-sectional view for explaining a manufacturing method of a glass light emitting device having a ridge-type waveguide structure in which a groove or a convex stripe-shaped projection is formed by using a replica method according to the present invention and a waveguide structure is formed.

FIG. 3 is a cross-sectional view for explaining a method for manufacturing a glass light-emitting device having a ridge-type waveguide structure in which a groove and a convex stripe-shaped protrusion are formed by using a selective etching method according to the present invention to form a waveguide structure. .

FIG. 4 is a cross-sectional view for explaining a method for manufacturing a glass light-emitting device having a ridge-type waveguide structure in which a groove or a convex stripe-shaped protrusion is formed by using a replica method according to the present invention to form a waveguide structure.

FIG. 5 is a cross-sectional view for explaining a method of manufacturing a glass light-emitting device having a ridge-type waveguide structure in which a groove or a convex stripe-shaped protrusion is formed by using a replica method according to the present invention to form a waveguide structure.

FIG. 6 is a cross-sectional view for explaining a method of manufacturing a glass light-emitting device having a buried waveguide structure in which a rectangular stripe-shaped protrusion is formed by using a selective etching method according to the present invention to form a waveguide structure.

FIG. 7 is a cross-sectional view for explaining a method of manufacturing a glass light emitting device having a buried waveguide structure in which a rectangular stripe-shaped protrusion is formed by using a selective etching method according to the present invention to form a waveguide structure.

8 is a selective etching mask used when manufacturing the glass light emitting device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Lower clad glass thin film 3 Lower clad glass thin film with groove 4 Selective etching mask 5 Core glass thin film including luminescent medium 6 Upper clad glass thin film 7 Flat plate having convex stripe projections 8 Core glass thin film including luminescent medium 9 Selective etching mask 10 Core glass thin film with convex stripe-shaped protrusions 11 Upper clad glass thin film 12 Flat plate with grooves 13 Flat plate with double convex stripe protrusions 14 Core glass thin film with double grooves 15 Upper clad Glass thin film 16 Stripe core glass thin film with square cross section 17 Upper clad glass thin film 18 Tapered selective etching mask 19 Tapered core glass thin film with square cross section 20 Upper clad glass thin film

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Osamu Niibori 2-3-2 Nishishinjuku, Shinjuku-ku, Tokyo International Telegraph and Telephone Corporation (56) References JP-A-64-26805 (JP, A) JP-A-3-53202 (JP, A) JP-A-60-129711 (JP, A) JP-A-64-26806 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01S3 / 17 G02B 6/12 G02B 6/13 H01S 3/07

Claims (6)

(57) [Claims] A step of forming at least one lower clad glass thin film on a substrate by a physical vapor deposition method or a chemical deposition method; and a step of forming at least one kind of groove in the lower clad glass thin film by a selective etching method. Forming at least one core glass thin film comprising at least one luminescent medium and at least one upper clad glass thin film by physical vapor deposition or chemical deposition on the lower clad glass thin film having the groove formed thereon. Wherein the clad thin film and the core glass thin film are
_A method for producing a waveguide glass laser comprising a fluoride glass comprising at least one of InF ₃ and InF ₃ and ZnF ₂ and PbF ₂ or a fluoride glass comprising PbF ₂ and AlF ₃ . 2. A step of forming at least one lower clad glass thin film on a substrate by a physical vapor deposition method or a chemical deposition method, and forming a flat plate having at least one kind of stripe-shaped convex portion by glass softening of the lower clad glass thin film. A step of forming at least one kind of groove in the lower clad glass thin film by pressing the lower clad glass thin film in a state of being heated to a temperature close to a temperature, and at least one layer on the formed lower clad glass thin film having the groove. and forming at least the upper cladding glass film become more and more a core glass film comprising at least one light-emitting medium in the physical vapor deposition method or chemical deposition method, and the core glass thin film and the clad film, and GaF ₃ At least one, and either a fluoride glass composed of ZnF ₂ and PbF ₂ of InF _3, or PbF ₂ and AlF ₃ A method for producing a waveguide glass laser using a fluoride glass. Forming a core glass thin film comprising at least one lower clad glass thin film and at least one light emitting medium on a substrate by physical vapor deposition or chemical deposition, and said core glass; A step of forming at least one type of stripe-shaped convex portion or a stripe having a square cross section which is a special case thereof by a selective etching method on the thin film, and forming the stripe-shaped convex portion or the stripe on the core glass thin film formed with Forming at least one upper clad glass thin film by physical vapor deposition or chemical deposition, wherein the clad thin film and the core glass thin film are formed from at least one of GaF ₃ and InF ₃ and ZnF ₂ and PbF _2. Waveguide glass laser made of fluoride glass made of PbF ₂ and AlF ₃ Manufacturing method. Forming a core glass thin film comprising at least one lower clad glass thin film and at least one luminescent medium on a substrate by a physical vapor deposition method or a chemical deposition method; Forming at least one stripe-shaped projection on the core glass thin film by pressing a flat plate having a stripe-shaped concave portion against the core glass thin film in a state of being heated near the glass softening temperature of the core glass thin film; look including a step of forming an upper clad glass film at least become more and more a physical vapor deposition or chemical deposition method convex portion the core on glass thin film formed of the clad film and before
A serial core glass film, GaF ₃ and InF ₃ of at least a
And a fluoride glass consisting of ZnF ₂ and PbF ₂
Or a fluoride glass consisting of PbF ₂ and AlF ₃
Of manufacturing a waveguide glass laser. 5. The method according to claim 1, wherein the clad glass thin film and the core glass thin film are formed of at least one of GaF ₃ and InF ₃ and ZnF ₂ and Pb.
Waveguide glass laser manufacturing method according to claim 4 which is a fluoride glass composed of F _2. 6. The method of manufacturing a waveguide glass laser according to claim 4, wherein said clad glass thin film and said core glass thin film are made of fluoride glass made of PbF ₂ and AlF ₃ .