JPH0695190A - Optical wavelength conversion element manufacturing equipment - Google Patents

Abstract

(57) [Summary] [Object] To provide an optical wavelength conversion element manufacturing apparatus capable of evaluating the orientation direction or the crystalline state of an organic single crystal forming a core in the process of manufacturing a fiber type optical wavelength conversion element. An optical wavelength conversion device manufacturing apparatus for manufacturing a fiber-type optical wavelength conversion device by growing an organic single crystal having a non-linear optical effect in a capillary, wherein the capillary is inserted and arranged, and the capillary is heated from the outer peripheral surface. A ring furnace, a transport mechanism for axially advancing and retracting the capillary inserted through the ring furnace, and a polarization microscopic Raman scattering spectroscopy system for detecting and identifying an organic single crystal growing in the capillary. It is characterized by being formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light wavelength conversion device manufacturing apparatus, and more particularly to a light wavelength conversion device provided with means for evaluating the orientation and orientation of the organic single crystal forming the core and the crystal state in the manufacturing process. Manufacturing equipment

[0002]

2. Description of the Related Art In the field of optronics using a laser beam, for example, in order to increase the recording density, there is an increasing demand for a light source having a shorter wavelength, a higher output and a smaller size. SHG) or a combination with an optical wavelength conversion element that uses the phenomenon of third harmonic generation (THG) constitutes one form. Here, as an optical wavelength conversion element to be combined with a semiconductor laser, an organic single crystal having a nonlinear optical effect, more specifically an SHG-active or THG-active organic organic material, is provided inside a glass or plastic capillary as a clad. SHG or THG fiber-type optical wavelength conversion devices that are filled with a single crystal as the core are well known. FIG. 2 is a cross-sectional view showing an example of the structure of such a fiber type optical wavelength conversion element. Reference numeral 1 is a core made of an organic single crystal having a nonlinear optical effect, and 2 is a clad made of capillaries.

The fiber type optical wavelength conversion element of this type is generally manufactured as follows. That is, an SHG-active or THG-active organic single crystal is grown inside a glass or plastics capillary with a length of several tens of centimeters in a constant-temperature furnace, and the capillary is the cladding and the fiber with the organic single crystal as the core. After making, cut this fiber to a length of about 5-10 mm,
It is used as a fiber type optical wavelength conversion element.

By the way, in the fiber type optical wavelength conversion element, the orientation direction (crystal axis direction) of the organic single crystal forming the core is SHG fiber type optical wavelength conversion element, THG
It affects the performance of the fiber type optical wavelength conversion element. In other words, since the refractive index and the values of the second-order and third-order nonlinear optical constants of organic materials generally differ depending on the crystal orientation, changes in the orientation of the crystal depend on the SHG fiber type optical wavelength conversion element, TH
This is because the conversion efficiency of the G fiber type optical wavelength conversion element and the emission angle of the second harmonic (SH) light and the third harmonic (TH) light are changed. Therefore, in the fiber type optical wavelength conversion element, the orientation direction of the organic single crystal forming the core must be suppressed, and a measure for evaluating the orientation direction of the organic single crystal grown in the capillary is required.

However, in the fiber-type optical wavelength conversion element, the conversion efficiency of SHG and THG is better when the mode of the fundamental wave guided through the core is single. It is selected and set to about 10 μm. Therefore, X-ray diffraction is also impossible, and as a result, the orientation direction of the crystal cannot be evaluated. If the core diameter is about several tens of μm, X-ray diffraction is also possible, but in this case it is necessary to remove the clad part by etching, etc. It cannot be used as a conversion element.

[0006]

As described above, in the fiber type optical wavelength conversion element, there is no suitable means for evaluating the orientation direction of the organic single crystal forming the ko until now when the incident light is actually incident. The performance could not be evaluated and confirmed without measuring the conversion efficiency and the emission angle of the output light, and the product could not be immediately incorporated into the short wavelength laser system. Moreover, at this time, since it is necessary to determine the orientation direction of the organic single crystal that forms the core in order to determine the polarization direction of the incident light, the polarization direction of the incident light is repeatedly incident on the fiber-type optical wavelength conversion element. It was decided by trial and error. That is, in the fiber type optical wavelength conversion element, the polarization of the incident light is determined by trial and error,
After confirming the performance by measuring the conversion efficiency and the emission angle of the output light, only good products will be incorporated into the short wavelength laser system for the first time, so there are many practical problems such as manufacturing cost, productivity, and poor yield. It was

The present invention has been made in consideration of the above circumstances, and the orientation direction or crystal state of an organic single crystal forming a core can be evaluated in the manufacturing process, and a fiber type optical wavelength conversion element can be manufactured with high productivity. It is an object of the present invention to provide an optical wavelength conversion element manufacturing apparatus capable of performing the same.

[0008]

An optical wavelength conversion element manufacturing apparatus according to the present invention is an optical wavelength conversion element manufacturing method for manufacturing a fiber type optical wavelength conversion element by growing an organic single crystal having a non-linear optical effect in a capillary. An apparatus, in which a capillary is inserted and arranged, an annular furnace for heating the capillary from the outer peripheral surface, a transport mechanism for axially advancing and retracting the capillary inserted and arranged in the annular furnace, and an organic compound that grows in the capillary A polarization microscope Raman scattering spectroscopy system is provided for detecting and identifying a single crystal. That is, the present invention is an apparatus for producing a fiber type optical wavelength conversion element by treating an organic compound housed in a so-called capillary in a zone-melting manner and growing the organic single crystal in a certain direction. The essence is that a polarized light Raman scattering spectroscopic system that evaluates the orientation and orientation is attached.

Here, as a light source for the polarized light Raman scattering spectroscopy, Ar ion laser, He-Ne laser, dye laser, YAG laser, YLF laser, Ti sapphire laser, semiconductor laser, and harmonic light thereof are used. It is possible, and the absorption wavelength of the organic material used for the core is taken into consideration when selecting the light source.

[0010]

The polarized microscopic Raman scattering spectroscopy system additionally provided in the present invention makes it possible to easily determine the orientation direction of an organic single crystal that grows in a certain direction without removing the clad portion even when the core diameter is about 1 μm. . That is, SH
In G, THG active organic single crystals, the Raman spectrum differs depending on the polarization direction of the incident light. Therefore, if the relationship between the crystal orientation and the Raman spectrum of the polarization direction of the incident light used in advance is understood, it was detected. The orientation direction of the crystal can be determined by the Raman spectrum. At this time, it is also possible to inevitably determine the polarization direction of the incident light by determining and confirming the crystal orientation.
In the present invention, an S
It is also possible to avoid HG and THG fiber type optical wavelength conversion elements, or to identify such defective products, which greatly contributes to avoiding yield, productivity and cost increase.

[0011]

Embodiments of the present invention will be described below with reference to FIG.

FIG. 1 is a block diagram (schematic diagram) showing a structural example of a light wavelength conversion device manufacturing apparatus according to the present invention. Reference numeral 3 is a container for accommodating (accommodating) an organic substance to grow an organic single crystal in a predetermined direction. Glass capillaries 4 are annular furnaces which are inserted through the glass capillaries 3 and heated from the outer peripheral surface.
The annular furnace 4 is composed of a relatively low temperature region 4a and a relatively high temperature region 4b. Also,
Reference numeral 5 is a transfer mechanism for axially advancing and retracting and rotating the glass capillary 3 inserted through the annular furnace 4, 6, 7
Is a polarized light microscopic Raman scattering spectroscopy system for detecting and identifying the end face and the side face of the organic single crystal growing in the glass capillary 3. The polarized light Raman scattering spectroscopic systems 6 and 7 are microscopic lenses 6 arranged so as to face the end face and the side face of the organic single crystal, respectively.
a, 7a, Ar lasers 6b, 7b for Raman scattering excitation for performing Raman scattering spectroscopy via the microscope lenses 6a, 7a, and Raman scattering spectra reflected from the detected part by irradiating the detected portion with the microscope lenses 6a, 7a.
Spectroscopes 6c and 7c for receiving light via the photodetectors, photodetectors 6d and 7d for spectrally observing the received light at the spectroscopes 6c and 7c, and a computer 6e for organizing and evaluating the results at the photodetectors 6d and 7d.
It consists of (7e) and. Next, an example of use of the optical wavelength conversion device manufacturing apparatus having the above configuration will be described.

First, for example, a glass capillary 3 having an inner diameter of 1 μm was prepared, and an organic substance, 2-methyl-4-nitroaniline (MNA) (melting point: about 132 ° C.) which had been melted in vacuum at a temperature of 140 ° C. ) Was sucked up and stored in the glass capillary 3 by a capillary phenomenon. On the other hand, in the annular furnace 4, the low temperature region 4a is set to about 20 ° C. and the high temperature region 4b is set to about 140 ° C., and the glass capillary containing the organic substance is placed in the annular furnace 4. 3, the glass capillary 3 is slowly rotated by driving the transport mechanism 5 while pulling it up to the low temperature region 4a side along the axial direction to remove the organic substance (MNA) melted and contained therein. Grow a single crystal. In growing the single crystal, the crystal orientation is discriminated by the polarization microscopic Raman scattering spectroscopy system 6 on the upper end surface of the glass capillary 3. That is, while Raising the glass capillary 3 also moves the microscope lens 6a upward, Raman scattering spectroscopy and spectrum observation are performed to determine the crystal orientation of the generated organic single crystal. On the other hand, on the side surface of the glass capillary 3 to be pulled up, the polarized microscopic Raman scattering spectroscopy system 7
Similarly, microscopic Raman scattering spectroscopy and spectrum observation are performed on the side surface of the growing organic single crystal to determine the crystal orientation of the organic single crystal. When performing microscopic Raman scattering spectroscopy and spectrum observation on this side surface portion, at least one of the glass capillary 3 or the microscopic lens 7a arranged facing the side surface portion is rotated in the circumferential direction, It enables to discriminate the crystal orientation of the organic single crystal grown over the entire peripheral surface.

In the process of manufacturing the above optical wavelength conversion element,
Since the crystal orientation of the organic single crystal grown in the glass capillary is continuously discriminated, when the crystal orientation is not preferable, the production of the optical wavelength conversion element is stopped and the glass is transferred by the transport mechanism 5. It is possible to pull down the capillaries 3 to melt the organic substances in the glass capillaries 3 again and to advance the growth of the single crystal. Further, polycrystallization of crystals, mixing of impurities, and mixing of stereoisomers can be discriminated by the polarized light Raman scattering spectroscopic systems 6 and 7, and therefore discrimination and removal from a characteristic aspect are also possible. That is, not only can capillaries and organic substances be used without waste, but since the crystal orientation is determined in the manufacturing process of the fiber-type optical wavelength conversion element, the polarization direction of incident light can be inevitably determined. It can be incorporated into a short wavelength laser system without the need for conventional trial and error.

In the above, the configuration example of the optical wavelength conversion element manufacturing apparatus in which the annular furnace 4 is vertical is described, but the annular furnace 4 may have a horizontal structure. Further, in the above, an example of using 2-methyl-4-nitroaniline (MNA) as the organic substance and growing the single crystal as the core has been described.
For example, 3-acetamido-4-dimethylaminonitrobenzene (DAN), N- (4-nitrophenyl)-(S)
-When using prolinol (NPP), methyl (2,4-dinitrophenyl) aminopropionate (MAP), etc., a fiber-type optical wavelength conversion element having a desired crystal orientation could be produced in the same manner. .

[0016]

As described above, according to the optical wavelength conversion element manufacturing apparatus of the present invention, it is possible to use the raw materials and materials without waste, and the fiber type optical wavelength conversion element having the required excellent performance and characteristics. Can be manufactured with high productivity.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration example of an optical wavelength conversion element manufacturing apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing a configuration example of a fiber type optical wavelength conversion element.

[Explanation of symbols]

1 ... Core (organic single crystal) 2 ... Clad 3 ... Glass capillary 4 ... Annular furnace 4a ... Low temperature region 4b ... High temperature region
5 ... Transfer mechanism 6,7 ... Polarization microscope Raman scattering spectroscopy system 6a, 7a ... Microlens 6b, 7b ... Ar laser for Raman scattering excitation 6c, 7c ... Spectroscope 6d, 7d ... Photodetector
6e, (7e) ... Computer

Claims (1)

[Claims] 1. An optical wavelength conversion element manufacturing apparatus for manufacturing a fiber type optical wavelength conversion element by growing an organic single crystal having a nonlinear optical effect in a capillary, wherein the capillary is inserted and disposed, and the capillary is provided with an outer peripheral surface. An annular furnace that heats from the tube, a transport mechanism that axially advances and retracts a capillary that is inserted through the annular furnace, and a polarization microscopic Raman scattering spectroscopy system that detects and identifies an organic single crystal growing in the capillary. An apparatus for manufacturing an optical wavelength conversion element, comprising: