JPH06216456A - Manufacture of waveguide type glass laser - Google Patents

Abstract

PURPOSE:To manufacture a waveguide type glass laser which can take waveguide structure except for a columnar wave by forming a lower clad glass thin film on a semiconductor substrate, next forming a groove in the thin film by a selective etching method and further forming a core glass thin film containing a light emitting medium and an upper clad glass thin film. CONSTITUTION:A lower clad glass thin film 2 is formed on a GaAs substrate 1 by a method of sputtering fluoride glass used for an under clad glass. Next, An SiN thin film is deposited, a window is formed. The substrate 1 is used as a mask 4 for selective etching. A clad glass thin film is selectively etched by using a ZrOCl2-HCl etchant to form a groove and the SiN selective etching mask 4 is removed. After that, a fluoride glass thin film 5 for a core with Tm added as a light emitting substance and a fluoride glass thin film 6 for an upper clad glass are deposited on an lower clad thin film 3 with a groove formed by a magnetron sputtering method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a waveguide type 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 containing a light emitting medium, a waveguide structure is formed by a core in which the light emitting base material has a cylindrical shape and a light emitting medium is added and a clad glass having a lower refractive index than that of the core. There are glass fiber lasers and glass fiber amplifiers. Some of these guided glass lasers have excellent characteristics as compared with semiconductor lasers, and some of them are being put to practical use for application as long-distance optical communication devices.

Quartz glass and fluoride glass are mainly used as the light emitting base material of these lasers, and the above-mentioned fiber-shaped waveguide type glass laser manufacturing method can be applied to glass fiber manufacturing technology in any case. Has been developed based on. That is, in the case of quartz glass,
The VAD method or MCVD method is combined with the so-called immersion method to form a luminescent matrix glass with a luminescent medium added (herein called vapor-liquid immersion method). As an example, VAD method is used to prepare core soot (glass particles), which is soaked in an alcohol solution containing a rare earth element halide, which is a light emitting medium, and then sintered to form a core rod. A glass preform is formed by sintering, and a glass fiber is spun from this to manufacture a laser.

On the other hand, in the case of fluoride glass, a multi-component melt of metal fluoride is prepared as two melts for the core and the clad, and the clad melt is first poured into the mold and the outside of the clad melt contacting the mold is solidified. Then, after an appropriate period of time in which the central part is still in the melt state, the part in the melt state is removed from the mold, and the core glass melt is poured into the space formed at this time to cool the glass preform. To form. At this time, the rare earth element fluoride, which is a light emitting medium, is simultaneously melted in the core glass melt to form a preform for a glass laser in which the light emitting medium is added to the core (referred to as a simultaneous melt method here). From this, a glass fiber is spun to manufacture a guided glass laser.

[0005]

However, when a fluoride glass is taken as an example, a glass having excellent transmission characteristics as a bulk glass, for example, ZnF ₂ -GaF ₃ -InF ₃ -PbF ₂ based glass or P
Despite the presence of bF ₂ -AlF ₃ based glass, it was not possible to fabricate a waveguide type glass laser using the glass as a glass emission base material in the above-mentioned conventional technique. This is because the conventional guided glass laser manufacturing method can manufacture a guided glass laser only from a part of the fluoride glass, which has particularly excellent glass stability, and even if the transmission characteristics are excellent, This is because glass systems that are not highly stable could not be targeted. That is, the conventional method can be applied only to a few of the fluoride glasses which are particularly easy to vitrify.

How important the glass stability is in the conventional fluoride-guided glass laser manufacturing process will be described. The stability of glass is a problem in the conventional waveguide glass laser manufacturing process, the cooling process of the glass melt and the reheating process of the clad glass near the core-clad glass interface in the first stage glass preforming process. And in the reheating process in the second stage fiber spinning process.

When discussing glass stability, there are two indicators: crystallization onset temperature T _x and glass transition temperature T _g.
Difference ΔT = T _x −T _g and the critical cooling rate.
In general, the crystal growth rate and the nucleation rate have temperature dependences that are maximum near the crystallization start temperature and the glass transition temperature, respectively. Therefore, the difference ΔT = T _x −T _g between the crystallization start temperature and the glass transition temperature corresponds to the degree of overlap between the crystal growth rate and the nucleation rate as a function of temperature. That is, when ΔT is large, the degree of overlap between the two is small, crystals are less likely to appear, and 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 that does not contain crystals.The smaller this value is, the more vitrification is possible without rapid cooling. It indicates that the property is high.

From the viewpoint of the above-mentioned two indexes, a glass system to which the conventional waveguide type glass laser manufacturing method can be applied will be discussed. The conventional manufacturing method is limited to a glass system having a small critical cooling rate and a large ΔT. . The critical cooling rate was measured for some fluoride glass compositions and reported values in the range of 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 most practical cases where a waveguide glass laser was manufactured by the conventional method, ZrF ₄ -HfF ₄ -BaF ₂ -LaF ₃ -AlF ₃ -NaF system glass is used as the glass base material in most cases. Because of the extraordinary glass stability of.

On the other hand, although there is no data on the critical cooling rate of ZnF ₂ -GaF ₃ -InF ₃ -PbF ₂ type glass, ΔT is 40-60 K, and ZrF ₄ -HfF ₄ -BaF ₂ -LaF _3- In AlF ₃ -NaF glasses
It's much smaller than 90K. In fact, ZnF ₂ -GaF _3-
In the InF ₃ -PbF ₂ system glass, the glass can be produced by the method of pouring the glass melt into the mold and quenching it only in the non-waveguide structure where the reheating process of the glass does not matter so much. It is not possible to make structured glass preforms. In addition, PbF ₂ -AlF ₃ based glass can be vitrified for the first time by using a special manufacturing method that can achieve a very high cooling rate, and even in that case, only thin ribbon glass can be produced.

As described above, in the waveguide type glass laser which can be produced by the conventional technique, only the ZrF ₄ -HfF ₄ -BaF ₂ -LaF ₃ -AlF ₃ -NaF type glass can be used as the glass base material. Was there. Z that extends the infrared transmission wavelength range from this glass system
Although the existence of nF ₂ -GaF ₃ -InF ₃ -PbF ₂ glass-based and PbF ₂ -AlF ₃ -based glasses is known, it is important to fabricate these glass-based lasers by conventional techniques from the viewpoint of glass stability. Because it was impossible. Further, there has not been disclosed a technique relating to a method of producing a waveguide type glass laser using these glass systems having low stability as a light emitting base material.

The above has been a description of the problems in the method of manufacturing a waveguide type fluoride glass laser. Here, the shortcomings of the prior art are summarized below. (1) The material of the luminescent base material is SiO ₂ · GeO _{2 in the} vapor-liquid immersion method.
In addition, in the simultaneous melt method, it is limited to some metal fluoride multi-component system which becomes glass by quenching from the melt, and other glasses cannot be used as the light emitting base material The degree of freedom of was very 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 method of improving the light emitting characteristics by changing the type of the light emitting base material is usually used in this field. However, due to (1), the degree of freedom in selecting the light emitting base material glass is small, and thus there is a limit to improvement of the light emitting characteristics. (3) The maximum wavelengths in the transmission wavelength range of quartz glass and fluoride glass that can be used as the luminescent base glass are 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 is difficult to manufacture a laser with a wavelength range exceeding this range. (4) Whether quartz glass or fluoride glass, the shape of the light-emitting base material produced by the above method is limited to a cylindrical shape, and no other waveguide structure can be formed.

An object of the present invention is to improve the above-mentioned drawbacks of the prior art, and to produce a waveguide type glass laser capable of taking a waveguide structure other than a cylindrical shape without limiting the kinds of glass materials usable as a light emitting base material. It is an object of the present invention to provide a method of manufacturing a guided glass laser that can be manufactured.

[0013]

In order to achieve this object, the present invention provides 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 deposition method, or the like. The thin film forming method classified as the chemical vapor deposition method is used as a means for forming a glass thin film and a means for adding a luminescent medium, which is to be changed to a vapor-liquid immersion method and a simultaneous melt method, and has a selective etching method or a specific pattern on the surface A waveguide type glass laser is manufactured 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.

[0014]

By the manufacturing method of the present invention, the types of glass materials that can be used as the light-emitting base material can be greatly expanded,
The degree of freedom in selecting the light emitting base material glass can be greatly increased. This also means that the characteristics of the laser can be improved by optimizing the light emitting base material glass, and further, the transmission wavelength region of the glass can be extended to the long wavelength side particularly in the infrared region. Therefore, it is possible to manufacture a guided glass laser in the far infrared region, which cannot be realized by the conventional technique. 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 a cylindrical shape can be manufactured. As a result, the present invention can solve the present problem to improve the above disadvantages (1) to (4).

[0015]

EXAMPLE An example of a method of manufacturing a ridge-type waveguide structure glass laser will be described. [Example 1] A lower clad glass thin film is formed on a semiconductor substrate, a groove is then formed in this thin film by a selective etching method, and a core glass thin film containing a light emitting medium and an upper clad glass thin film are formed. An example of manufacturing a corrugated glass laser, an example of a method of manufacturing a thin film waveguide glass laser that is a fluoride glass material that can be vitrified by the conventional simultaneous melting method but cannot be manufactured by the conventional technology. Is shown in FIG. First, on a GaAs (100) substrate 1, a fluoride glass for lower clad glass, such as 40% ZrF ₄ -13
% HfF ₄ -20% BaF ₂ -4% LaF ₃ -3% AlF ₃ -20% NaF is used as a target to form a lower clad glass thin film 2 with a thickness of 10 μm by a sputtering method, for example, magnetron sputtering method [Fig. 1 (A). Next, a SiN thin film is deposited on the clad glass thin film by the plasma CVD method, and a window having a width of 20 μm is formed by a normal photoetching process to form the selective etching mask 4. ZrOC
The clad glass thin film is selectively etched using the l ₂ -HCl-based etchant as a selective etchant to form a groove having a depth of 2 μm [FIG. 1 (b)]. Then, the SiN selective etching mask is removed with a hydrofluoric acid-based etchant. After that, on the lower clad thin film 3 in which the groove is formed, a fluoride glass for the core, in which Tm is added as a light emitting medium by using a magnetron sputtering method, for example, 53% ZrF ₄ -20% BaF ₂ -4% LaF ₃ -3% Al
F ₃ -20% NaF and fluoride glass for upper cladding glass, e.g. 40% ZrF ₄ -13% HfF ₄ -20% BaF ₂ -4% LaF ₃ -3% AlF ₃ -20% NaF
Targeting each of the core thin film 5 with a thickness of 8 μm
And an upper clad thin film 6 with a thickness of 10 μm is deposited [Fig. 1
(C)]. Then, the GaAs substrate is polished to a thickness of 150 μm and cleaved to form a flat glass multi-layered film end face without irregularities. After that, one end face is 0 for the excitation light.
% An optical film with a reflectance of near 100% for laser oscillation light, and an optical film with an appropriate reflectance for 100% laser light for excitation light on the other end face. It is attached by the beam evaporation method. This results in a length of 10 cm and a width of 1.
It is possible to fabricate a waveguide glass laser having a ridge waveguide structure with a waveguide width of 20 μm in cm. In this laser, for example, a waveguide type glass laser that oscillates at a wavelength of 2.31 nm can be obtained by exciting the light emitting region of the core thin film 5 in a direction perpendicular to the paper surface with a laser beam having a wavelength of 670 nm.・ It can be used as a light source with high light condensing and coherence.

EXAMPLE 2 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 metal plate having (convex stripe-shaped protrusions) is pressed against the lower clad glass thin film to form a groove, and a core glass thin film containing a light emitting medium and an upper clad glass thin film are formed to form a waveguide glass laser. FIG. 2 shows an example of a method of producing a thin film waveguide glass laser, which is a fluoride glass material that can be vitrified by the conventional simultaneous melting method, but cannot be produced by the conventional technology. . GaAs
(100) Fluoride glass for lower clad glass on substrate 1, eg 40% ZrF ₄ -13% HfF ₄ -20% BaF ₂ -4% LaF ₃ -3% AlF ₃ -2
A lower cladding glass thin film 2 having a thickness of 10 μm is formed by a sputtering method, for example, a magnetron sputtering method using 0% NaF 3 as a target [FIG. 2 (a)]. Next, with the lower clad glass thin film heated near the glass softening temperature of the lower clad glass, the width is 20 m and the step is 2 μm.
The Ni flat plate 7 having the convex stripe-shaped projections on the surface is pressed against the lower clad glass thin film and then removed to form a groove with a width of 20 μm and a step of 2 μm on the surface of the lower clad glass thin film as a replica of the Ni flat plate [Fig. Two
(B)]. After that, on the lower clad thin film 2 in which the groove is formed, a magnetron sputtering method is used to add Er as a light emitting medium to the core fluoride glass, for example, 53% Zr.
F ₄ -20% BaF ₂ -4% LaF ₃ -3% AlF ₃ -20% NaF and fluoride glass for upper cladding glass, e.g. 40% ZrF ₄ -13% HfF ₄ -20% BaF ₂
Targeting -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 deposited [FIG. 2 (c)]. next,
A GaAs substrate is polished to a thickness of 150 μm, and GaAs is cleaved to form a flat glass multi-layered film end face with no irregularities. After that, one end face is coated with an optical film having a reflectance close to 100% with respect to 0% laser oscillation light with respect to the excitation light, and the other end face with respect to 100% laser light against the excitation light. An optical film having an appropriate reflectance is attached by, for example, electron beam evaporation method. As a result, the length is 10 cm, the width is 1 cm, and the waveguide width is 20 cm.
It is possible to fabricate a guided glass laser with a μm ridge waveguide structure. In this laser, for example, the wavelength
By exciting the light-emitting region of the core thin film 5 with a laser beam of 790 nm in a direction perpendicular to the paper surface, a guided glass laser that oscillates at a wavelength of 2.75 nm can be obtained. It can be used as a coherent light source.

Example 3 A lower cladding glass thin film and a core glass thin film containing a light emitting medium are formed on a semiconductor substrate,
Next, in this embodiment, a waveguide-type glass laser is manufactured by forming convex stripe-shaped protrusions on the core glass thin film by a selective etching method and further forming an upper clad glass thin film. FIG. 3 shows an example of a method of manufacturing a waveguide type glass laser using a light emitting base material of a fluoride glass material which cannot be vitrified by the liquid method. On the GaAs (100) substrate 1, using the molecular beam method, the fluoride glass for the lower clad glass 22% ZnF ₂ -32% GaF ₃ -46% PbF ₂ ZnF ₂ , GaF ₃ , PbF ₂ Is a constituent of the lower clad glass thin film 2 with a thickness of 10 μm and the fluoride glass 20% ZnF ₂ -32% GaF ₃ -48% PbF ₂ for the core glass.
ZnF ₂ , GaF ₃ , PbF ₂ and ErF ₃ added as a luminescent medium
Is used as a molecular beam source to form a core thin film 8 having a thickness of 8 μm (FIG. 3 (a)). 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 an ordinary photoetching process to form a selective etching mask 9. The cored glass thin film is selectively etched by the sputtering etching method to form convex stripe-shaped protrusions having a step difference of 2 μm [FIG. 3 (b)]. Then, the Ti selective etching mask is removed by a reactive ion etching method. Then, using the molecular beam method on the core glass thin film 10 on which the convex protrusions are formed, the fluoride glass for the upper clad glass 22% ZnF ₂ -32% GaF ₃ -46% PbF ₂ which is a constituent component ZnF ₂ , GaF ₃ , PbF ₂ as the molecular beam source,
An upper clad thin film 11 of m is deposited [FIG. 3 (c)].
Then, the GaAs substrate is polished to a thickness of 150 μm and cleaved to form a flat glass multi-layered film end face without irregularities.
After that, one end face is coated with an optical film having a reflectance close to 100% with respect to 0% laser oscillation light with respect to the excitation light, and the other end face with respect to 100% laser light against the excitation light. An optical film having a suitable reflectance is attached by, for example, an electron beam evaporation method. As a result, the length of the waveguide is 10 cm and the width is 1 cm.
It is possible to fabricate a waveguide type glass laser having a 20 μm ridge type waveguide structure and using ZnF ₂ —GaF ₃ —PbF ₂ system glass as the light emitting base material glass. In this laser, for example,
By exciting the light-emitting region of the core glass thin film 10 with a laser beam of 55 nm in a direction perpendicular to the plane of the paper, a guided glass laser that oscillates at a wavelength of 3.50 μm can be obtained. -Can be used as a coherent light source. The guided glass laser with ErF _{3 as the} light emitting medium is ZrF ₄ -BaF ₂ -LaF _3-
It can also be realized by a conventional manufacturing method using AlF ₃ -NaF glass as a light emitting base material. However, while the infrared transmission wavelength range is up to 3.6 μm in this glass system, ZnF ₂ -Ga
In the F ₃ -PbF ₂ system glass, it reaches up to 9 μm, so the oscillation wavelength
The loss value of the light-emitting base material at 3.50 μm is smaller in the latter case, and a laser with a smaller oscillation threshold can be obtained.

Example 4 A lower clad glass thin film and a core glass thin film containing a light emitting medium are formed on a semiconductor substrate,
Next, by pressing a metal plate having grooves on the core glass thin film while heating the core glass thin film to a temperature near the glass softening temperature of the core glass, a convex striped protrusion is formed on the surface of the core glass thin film, and the upper clad is further formed. An example of manufacturing a guided glass laser by forming a glass thin film. A method of manufacturing a guided glass laser using a fluoride glass material, which cannot be vitrified by the conventional co-melting method, as a light emitting base material. An example of the above is shown in FIG. On GaAs (100) substrate 1, PbF ₂ and AlF ₃ which are the constituents of fluoride glass 70% PbF ₂ -30% AlF ₃ for the lower clad glass were used as the evaporation source by the electron beam evaporation method. 10 μm lower clad glass thin film 2 and 73% fluoride glass for core glass
A core thin film 8 having a thickness of 8 μm is formed by using PbF ₂ , AlF ₃ which is a constituent of PbF ₂ -27% AlF ₃ and DyF ₃ added as a light emitting medium as a vapor deposition source [FIG. 4 (a)]. Next, with the core glass thin film heated near the glass softening temperature of the core glass, a Ni flat plate 12 having a groove with a width of 20 μm and a depth of 2 μm on the surface 12
Is pressed against the lower clad glass thin film and then removed so that a width of 20 mm is replicated on the core glass thin film surface as a replica of the Ni plate.
A convex stripe-shaped protrusion having a step size of 2 μm is formed [FIG. 4 (b)]. Then, on the core glass thin film 10 on which the convex stripe-shaped protrusions are formed, an electron beam evaporation method is used to form a fluoride glass 70% PbF ₂ -30% Al for the upper clad glass.
Using PbF ₂ and AlF ₃ which are the constituents of F ₃ as the evaporation source,
An upper clad glass thin film 11 of 10 μm is deposited [Fig. 4
(C)]. Next, the GaAs substrate is polished to a thickness of 150 μm, and a flat glass-like multi-layered film end face with no irregularities is formed by cleaving GaAs. After that, one end face is coated with an optical film having a reflectance close to 100% with respect to 0% laser oscillation light with respect to the excitation light, and the other end face with respect to 100% laser light against the excitation light. An optical film having an appropriate reflectance is attached by, for example, electron beam evaporation method. As a result, the length is 10 cm,
A waveguide glass laser having a ridge waveguide structure with a width of 1 cm and a waveguide width of 20 μm can be manufactured. In this laser, the light emission region of the core glass thin film 10 is set to, for example, a wavelength of 1.7
It can be used as a guided glass laser that oscillates at a wavelength of 4.34 μm when it is excited by a laser beam of 3 μm in a direction perpendicular to the paper surface, and it is used as a high-intensity, high-focusing, coherent light source in the far infrared region. it can. In the conventional method of manufacturing a waveguide type glass laser, the glass usable as the light emitting base material is in the infrared transmission wavelength range of 3.6.
Since it was a ZrF ₄ -BaF ₂ -LaF ₃ -AlF ₃ -NaF system glass up to μm, it was not possible to fabricate a glass laser outside the infrared transmission wavelength range of this glass as in this example.
Only when the manufacturing method according to the present invention is applied, a waveguide type PbF ₂ -AlF ₃ system glass laser, which cannot be realized by the conventional manufacturing method, can be manufactured, and it becomes possible to oscillate at a wavelength of 4.34 μm.

Example 5 A lower cladding glass thin film and a core glass thin film containing a light emitting medium are formed on a semiconductor substrate,
Next, while the core glass thin film is heated to near the glass softening temperature of the core glass, a metal plate having double convex stripe-shaped protrusions is pressed against the core glass thin film to form a double groove on the surface of the core glass thin film. In this embodiment, a waveguide type glass laser is manufactured by further forming an upper clad glass thin film and forming a waveguide glass laser using a fluoride glass material, which cannot be vitrified by the conventional co-melting method, as a light emitting base material. FIG. 5 shows an example of a method of manufacturing a mold glass laser. Ga
Fluoride glass for the lower clad glass 22% ZnF ₂ -32% GaF ₃ -46% PbF ₂ is used as a target on the As (100) substrate 1 by a sputtering method such as magnetron sputtering to form a lower clad with a thickness of 10 μm. Fluoride glass for core 2 with glass thin film 2 and HoF ₃ added as a light emitting medium 2
Targeting 0% ZnF ₂ -32% GaF ₃ -48% PbF ₂ and thickness 8μm
And the core thin film 14 are formed [FIG. 5 (a)]. Next, with the core glass thin film heated near the glass softening temperature of the core glass, double convex projections in which 20 μm wide and 2 μm stepped stripe-shaped protrusions are arranged in double at intervals of 20 μm are formed on the surface. The Ni flat plate 13 is pressed against the lower clad glass thin film and then removed to remove Ni on the surface of the core glass thin film.
As a replica of a flat plate, the grooves with a width of 20 μm and steps of 2 μm are spaced.
Double grooves arranged at 20 μm are formed [FIG. 5 (a)]. Then, using a magnetron sputtering method on the core glass thin film 14 with the double groove formed, targeting a fluoride glass 22% ZnF ₂ -32% GaF ₃ -46% PbF ₂ for the upper clad glass, a thickness of 10 μm. The upper clad glass thin film 15 is deposited [FIG. 5 (b)]. Next, polish the GaAs substrate
The thickness is 150 μm, and a flat glass-like multi-layered film end face with no irregularities is formed by cleaving GaAs. After that, one end face is coated with an optical film having a reflectance close to 100% with respect to 0% laser oscillation light with respect to the excitation light, and the other end face with respect to 100% laser light against the excitation light. An optical film having a suitable reflectance is attached by, for example, an electron beam evaporation method. As a result,
It is possible to fabricate a waveguide glass laser having a ridge waveguide structure with a length of 10 cm and a width of 1 cm and a waveguide width of 20 μm. In this laser, when the light-emitting region of the core glass thin film 14 is excited by a laser beam having a wavelength of 640 nm, for example, in the direction perpendicular to the paper surface, a guided glass laser that oscillates at a wavelength of 2.89 μm can be obtained. High brightness and high light collection
It can be used as a coherent light source.

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

Example 6 A lower cladding glass thin film and a core glass thin film containing a light emitting medium are formed on a semiconductor substrate,
Next, this core glass thin film is processed into a rectangular shape by a selective etching method, and an upper clad glass thin film is further formed to manufacture a waveguide type glass laser. FIG. 6 shows an example of a method of manufacturing a waveguide type glass laser using a non-fluoride glass material as a light emitting base material. On the GaAs (100) substrate 1, a fluoride glass for the lower clad glass, for example, 22% Zn, is formed by using a sputtering method such as a magnetron sputtering method.
F ₂ -16% InF ₃ -16% GaF ₃ -46% PbF ₂ targeting thickness 10
The lower clad glass thin film 2 of μm and the fluoride glass for the core to which Er, Tm, Ho and Dy are added as the light emitting medium, for example, 20% ZnF ₂ -16% InF ₃ -16% GaF ₃ -48% PbF ₂ A core glass thin film 8 having a thickness of 8 μm is formed as a target [FIG. 6 (a)]. Next, a Ti thin film was deposited on the core glass thin film by electron beam evaporation, and a stripe with a width of 20 μm was formed on the Ti thin film by a normal photoetching process.
The glass etching mask 9 is used. Then, the core glass thin film is selectively etched by the sputter etching method to form a rectangular shape with a width of 20 μm and a height of 10 μm [Fig.
(B)]. Then, the Ti selective etching mask 9 is removed by a reactive ion etching method. Then, on the core glass thin film 16 processed into a square shape and the exposed lower clad glass thin film 2, a fluoride glass for the upper clad glass, for example, 2
Target 2% ZnF ₂ -16% InF ₃ -16% GaF ₃ -46% PbF ₂ ,
A 20 μm thick upper clad thin film 17 is deposited [Fig. 6
(C)]. Next, the GaAs substrate is polished to a thickness of 150 μm, and cleaved to form a flat glass multi-layered film end face without irregularities. After that, one end face is 0 for the excitation light.
For example, an optical film with a reflectance of about 100% for% laser oscillation light, and an optical film with a suitable reflectance for 100% of the excitation light on the other end face, such as It is attached by the electron beam evaporation method. This results in a length of 10 cm and a width of 1.
It is possible to fabricate a guided glass laser having a buried waveguide structure with a waveguide width of 20 μm in cm. In this laser, the light emitting region of the core glass thin film 16 has a wavelength of, for example, 640 nm,
Wavelength 2.31 μm, 2.70 μm, 2.88 μm, 4. when excited in the direction perpendicular to the paper surface with 647 nm, 790 nm, 1.73 μm laser light.
It can be a waveguide type glass laser that oscillates at 34 μm, and can be used as a light source for a high-intensity / high-focusing / coherent light source in the far-infrared region, for example, an infrared branching analysis device. The glass that can be used as the light-emitting base material in the conventional manufacturing method of the waveguide type glass laser is ZrF4-BaF2 in the infrared transmission wavelength range up to 3.6 μm.
Since it was a -LaF3-AlF3-NaF type glass, it was not possible to fabricate a glass laser having an oscillation wavelength outside the infrared transmission wavelength range of this glass as in this example. For the first time, the waveguide type ZnF ₂ -InF ₃ -GaF ₃ -PbF ₂ glass laser, which could not be realized by the conventional manufacturing method, can be manufactured by applying the manufacturing method according to the present invention, and multi-wavelength oscillation including the oscillation wavelength of 4.34 μm is possible. It is possible to manufacture a glass laser.

Example 7 A lower cladding glass thin film and a core glass thin film containing a light emitting medium are formed on a semiconductor substrate,
Next, this core glass thin film is processed into a square by a selective etching method, and an upper clad glass thin film is further formed to manufacture a waveguide type glass laser. A method of manufacturing a guided glass laser using a fluoride glass material that cannot be vitrified by the melt method as a light emitting base material, and the coupling efficiency with the guided glass laser excitation semiconductor laser and the guided glass laser emitted light is improved. FIG. 7 shows an embodiment of a method of manufacturing a waveguide type glass laser having a structure which is improved. GaAs (100) on the substrate 1, PbF ₂ is a component of the fluoride glass 70% PbF ₂ -30% AlF ₃ for the lower clad glass using a molecular beam method, AlF ₃
Adding a lower clad glass film 2 having a thickness of 10μm in the molecular beam source, and as PbF _2, AlF ₃ and the light emitting medium is a component of the fluoride glass 73% PbF ₂ -27% AlF ₃ for the core HoF 8μm thick core glass thin film with ₃ as molecular beam source
19 is formed [FIG. 7 (a)]. Next, a Ti thin film is deposited on the clad glass thin film by electron beam evaporation,
As shown in, one width is made close to the width of the light emitting layer of the semiconductor laser for excitation (for example, 100 μm), and the other width is made close to the core diameter of the fiber for emission (for example, 10 μm), and a tapered stripe between them is formed. Mask for glass etching, which is formed on the Ti thin film by a normal photo-etching process.
18 Then, the cored glass thin film 19 is selectively etched by the sputtering etching method. One end has a square shape with a width of 100 μm and a height of 10 μm, and the other end has a width of 10 μm.
A rectangular shape having a height of 10 μm is formed so that the width thereof changes in a tapered shape [FIGS. 7 (a) and 7 (b)]. Then, 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, a fluoride glass 70% Pb for the upper clad glass is formed by using the molecular beam method.
Using PbF and AlF ₃ which are constituents of F ₂ -30% AlF ₃ as a molecular beam source, an upper clad thin film 20 having a thickness of 30 μm is deposited [FIG. 7 (c) (d)]. Next, polish the GaAs substrate to a thickness of 150
μm, and the flat glass-like multi-layered film end face with no unevenness by cleaving operation. After that, an optical film with a reflectance of 0% for excitation light and 100% for laser oscillation light was formed on one end face, and 100% for excitation light was formed on the other end face.
An optical film having a suitable reflectance for the laser light is attached by, for example, an electron beam evaporation method. As a result, the length is 10 cm
It is possible to manufacture a waveguide glass laser having a buried waveguide structure having a width of 1 cm and capable of increasing the coupling efficiency with the excitation laser and the emission fiber. In this laser, the emission region of the core glass thin film 19 is, for example, a wavelength of 640 nm,
When excited with laser light of 647 nm and 790 nm in the direction perpendicular to the paper surface, it can be used as a guided glass laser that oscillates at wavelengths of 2.31 μm, 2.70 μm, and 2.88 μm.
It can be used as a light source of high light converging and coherent properties, for example, as a light source of an infrared branching analysis device.

In the above embodiment, as the thin film forming method, the sputtering method, the molecular beam method, the vacuum evaporation method (electron beam evaporation method,
Although it has been described only for the physical vapor deposition method (resistance heating method), other physical vapor deposition methods such as ionization vapor deposition method, high frequency induction heating method, reactive vapor deposition method, arc vapor deposition method, and laser vapor deposition method can also be used. It is feasible. Furthermore, CVD method, MOCVD
Method, a plasma CVD method, or another chemical deposition method.

In the above embodiments, the substrate material was described as a GaAs semiconductor substrate, but other semiconductor substrates such as In
It is also possible to use a P, GaSb semiconductor substrate. Further, the substrate material is not limited to the semiconductor substrate, and any substrate material can be arbitrarily selected according to the purpose as long as it can be used in the physical vapor deposition method or the chemical deposition method.

[0025] In the above embodiment, the glass luminescent matrix material as ZrF4-HfF4-BaF2-LaF3- AlF3-NaF system, ZnF ₂ -InF ₃ -GaF ₃ -
PbF ₂ system, PbF ₂ -AlF ₃ system described only in the fluoride glass, but compositions other than the compositions described in the examples, it is also possible to carry out a fluoride glass consisting of a combination of metal fluorides other than these combinations. it can. In addition, halide glass,
The chalcogenide glass, the oxide glass, or any material that can be manufactured by the physical vapor deposition method or the chemical deposition method, as well as the chalcogenide glass, can be used regardless of the material.

In the above embodiment, the shape of the thin film is described as a simple groove / convex / rectangular shape for simplification, but any structure that guides light may be used. Whatever shape is equivalent to the wave theory may be, for example, a deformed shape from a simple shape or a complicated shape obtained by modifying a simple shape.

Further, the thickness and width of the thin film in the above embodiment,
Numerical values regarding the depth of the groove, the length of the convex step, the width of the selective etching mask and the width of the Ni metal plate, the depth of the groove, the length of the convex step, etc. are not limited to these. Without
It suffices to correspond to a numerical value regarding the length of the waveguide structure calculated based on the optical waveguide theory.

[0028]

INDUSTRIAL APPLICABILITY The present invention can greatly expand the types of the luminescent base material glass as compared with the laser manufactured by the vapor phase-liquid immersion method and the simultaneous melt method which are the conventional techniques. The degree of freedom in selecting the glass can be greatly increased. This also means that the characteristics of the laser can be improved by optimizing the light emitting base material glass, and further, the transmission wavelength region of the glass can be extended to the long wavelength side particularly in the infrared region. Therefore, it is possible to manufacture a guided glass laser in the far infrared region, which cannot be realized by the conventional technique. According to this manufacturing method, since the glass thin film multilayer structure can be formed according to the shape of the substrate, it is possible to manufacture a laser having a shape other than the cylindrical shape by selecting the shape of the substrate.

According to the inventions of claims 3 and 4, the exposure apparatus for photo-etching and the apparatus for forming an etching mask thin film required for the selective etching method, for example, plasma CVD.
It has the effect of not requiring expensive equipment such as equipment, and can reduce the time-consuming steps such as the etching mask thin film forming step, the photoetching step, and the etching mask forming step in the selective etching method to a single step of pressing a flat plate. effective.

The invention of claim 5 of the present application is the ZnF ₂ -InF ₃ -GaF
_Since the infrared transmission wavelength range of the glass emission base material can be extended to 9 μm by using the glass thin film material of _3- PbF ₂ glass, it is possible to manufacture a waveguide type glass laser in the far infrared range. .

According to the invention of claim 6 of the present application, since the infrared transmission wavelength range of the glass light emitting base material can be extended to 18 μm by using PbF ₂ -AlF ₃ system glass as the glass thin film material, the far infrared range There is an effect that it is possible to manufacture a waveguide type glass laser.

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

When the method of forming a glass thin film by the sputtering method is used in the present invention, since the luminescent base material glass itself can be used as a vapor deposition source, it is possible to use other methods for producing a multi-component glass thin film. This is a more efficient thin film manufacturing method than the thin film manufacturing method.

When the method of forming a glass thin film using the vacuum vapor deposition method is used in the present invention, since the constituent substances of the luminescent base material glass are used as the vapor deposition source, it is difficult to fabricate the glass itself. Not only can it be used as a method, but it can be used as an efficient thin film forming method when the process of manufacturing glass itself is complicated and requires time.

[Brief description of 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 a selective etching method to form a waveguide structure according to the present invention. .

FIG. 2 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 a replica method to form a waveguide structure according to the present invention.

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 a selective etching method to form a waveguide structure according to the present invention. .

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

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 a replica method to form a waveguide structure according to the present invention.

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 projection is formed by a selective etching method to form a waveguide structure according to the present invention.

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 a selective etching method to form a waveguide structure according to the present invention.

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

[Explanation of symbols]

 1 Substrate 2 Lower Clad Glass Thin Film 3 Lower Clad Glass Thin Film with Grooves 4 Selective Etching Mask 5 Core Glass Thin Film Containing Luminous Medium 6 Upper Clad Glass Thin Film 7 Flat Plate with Convex Stripe Protrusion 8 Core Glass Thin Film Containing Luminous Medium 9 Selective Etching Mask 10 Core Glass Thin Film Forming Convex Stripe 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

Continuation of the front page (72) Inventor Osamu Shinbori 2-32 Nishishinjuku, Shinjuku-ku, Tokyo International Telegraph and Telephone Corporation

Claims (6)

[Claims] 1. 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. A step of forming a core glass thin film including at least one kind of luminescent medium and an upper clad glass thin film including at least one layer on the lower clad glass thin film formed with the groove by a physical vapor deposition method or a chemical deposition method. A method of manufacturing a guided glass laser, including: 2. A step of forming a lower clad glass thin film consisting of at least one layer on a substrate by a physical vapor deposition method or a chemical vapor deposition method, and a flattened plate having at least one kind of stripe-shaped convex portion to soften the glass 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 it against the lower clad glass thin film in a state of being heated to a temperature, and at least one layer on the lower clad glass thin film in which the groove is formed. A method of manufacturing a waveguide type glass laser, which comprises a step of forming a core glass thin film containing at least one kind of light emitting medium and an upper clad glass thin film consisting of at least one layer by a physical vapor deposition method or a chemical vapor deposition method. 3. A step of forming a core glass thin film consisting of at least one lower clad glass thin film and at least one layer containing at least one kind of luminescent medium on a substrate by physical vapor deposition or chemical deposition, and the core glass. A step of forming a stripe having at least one kind of stripe-shaped convex portion or a stripe having a rectangular cross section which is a special case of the thin film by a selective etching method, and forming the stripe-shaped convex portion or stripe on the core glass thin film Forming a top clad glass thin film consisting of at least one layer by physical vapor deposition or chemical vapor deposition. 4. A step of forming a core glass thin film consisting of at least one lower clad glass thin film and at least one layer containing at least one kind of luminescent medium on a substrate by physical vapor deposition or chemical deposition, and at least one A step of forming at least one stripe-shaped protrusion on the core glass thin film by pressing a flat plate having stripe-shaped recesses against the core glass thin film in a state of being heated to near the glass softening temperature of the core glass thin film; And a step of forming an upper clad glass thin film consisting of at least one layer on the core glass thin film on which the convex portion is formed by a physical vapor deposition method or a chemical vapor deposition method. 5. The cladding glass thin film and the core glass thin film are made of at least one of GaF3 and InF3, ZnF2 and PbF.
The method for producing a waveguide type glass laser according to claim 1, wherein the fluoride glass is made of 2. 6. The method for manufacturing a waveguide type glass laser according to claim 1, wherein the clad glass thin film and the core glass thin film are fluoride glasses made of PbF2 and AlF3.