KR0152211B1 - Method of preparing photoelements for wave guide - Google Patents

Abstract

The present invention provides a host device using a material obtained by dispersing a nonlinear optoelectronic compound represented by the following general formula (I) having a thermally stable electro-optic property and having a very low optical transmission loss in a polymer medium. The present invention relates to a method for manufacturing a host-guest optical waveguide optical device, which has excellent compatibility with a polymer medium, excellent electro-optic properties, does not thermally decompose at temperatures above 250 ° C, and does not sublimate. In addition, nonlinear optoelectronic compounds with very low optical transmission loss can be prepared.

In the above formula, R ₁ and R ₂ are C ₆ -C ₁₀ alkyl groups.

Description

Method of manufacturing optical waveguide optical device

1 is a schematic diagram of a method of measuring an electro-optic coefficient,

2 is a schematic diagram of a method of measuring the optical transmission loss rate.

* Explanation of symbols for main parts of the drawings

1: light source 2: polarizer

3: SB compensator 4: analyst

5: detector 6: lock certified aeration

7: glass 8: ITO

9 polymer 10 metal electrode

11: high refractive index prism 12: photodetector

13: waveguide 14: cladding

15: substrate

The present invention provides a host device using a material obtained by dispersing a nonlinear optoelectronic compound represented by the following general formula (I) having a thermally stable electro-optic property and having a very low optical transmission loss in a polymer medium. The present invention relates to a method for manufacturing an optical waveguide optical device of a host type.

In the above formula, R ₁ and R ₂ are C ₆ -C ₁₀ alkyl groups.

Photonic devices used for information communication have been manufactured using LiNbO ₃ mainly. Because optical element bandwidth using a LiNbO ₃ has become less than 10GHz-cm as an optical element for the next generation of information communication LiNbO ₃ is expected to hit the limits of use of the organic polymer having the electro-optical properties in order to solve the limitation of the LiNbO ₃ Research of light exchange devices using materials has been actively conducted worldwide.

Organic optoelectronic polymers, in particular, have very good nonlinear optical properties and are much faster to switch (50 picosec. Vs. 2nanose) than LiNbO ₃ and semiconductor materials.

c.) Very wide bandwidth (400 GHz vs. 10 GHz), easy to focus on existing optical fiber arrays and good processability, so that various optical devices such as linear optical waveguide wiring, phase modulators and mark-gender ( Mach-Zender interferometers, beam splitters, directional couplers, X-switches, etc. are much easier to integrate.

Although the optical device made of the organic polymer material is superior to the LiNbO ₃ optical device currently used, it has not been put to practical use until now because the electro-optical properties of the polymer material are not thermally stable and the optical transmission loss is large.

The organic polymers studied so far include a host-guest system obtained by injecting a nonlinear optoelectronic organic material into the polymer medium, and a side chain polymer covalently bonded to the polymer medium. Cross-linked polymers (cross-linked polymer) and the like cross-linked polymers, and especially cross-linked polymers have been reported to be stable even in the electro-optic properties of 100 ℃ or more.

Although crosslinked polymer materials have solved thermally stable electro-optic properties, there is a big problem of practical use because the optical transmission loss (10dB / cm) is very high. In addition, the organic polymer material of the host-guest optical device, which has been polarized by injecting nonlinear optoelectronic organic materials, has recently been reported to have stable electro-optic properties at 150 ° C, but the electro-optic effect is very small. There is a drawback that it can not be used to fabricate optical devices.

On the other hand, many polymer media that have been studied so far are commercial polymers such as polymethyl methacrylate (PMMA), but these media have low glass transition temperature (Tg), so that the oriented nonlinear optoelectronic compounds are easily oriented at the processing temperature. There was a disadvantage of being lost and losing its optical properties. In addition, there is a limit to increase the content of the nonlinear optoelectronic compound that has a critical effect on the optical properties because the compatibility between the commercial polymer of the host medium and the conventional nonlinear optoelectronic compound of the guest material is not large Large values of electrooptic coefficients could not be obtained.

Accordingly, an object of the present invention is to use a nonlinear optoelectronic compound having excellent compatibility with a polymer medium, excellent electro-optic properties, no thermal decomposition even at a temperature of 250 ° C. or higher, and no sublimation and a very low optical transmission loss. The present invention provides a method for manufacturing an optical waveguide optical device.

In order to achieve the above object as well as another object that is easily expressed in the present invention, the glass transition temperature is 150 ° C or more, so that it is thermally very stable to prevent relaxation of the nonlinear optoelectronic compound as a polymer medium. In order to have excellent compatibility with the precursor of polyimide, that is, a polymer medium, that is, polyamic acid, good thermal stability (sublimation and decomposition at processing temperature or curing temperature), and light transmission to minimize losses. The nonlinear optoelectronic compound of the following general formula (I), in which a specific functional group was added to the nonlinear optoelectronic compound of, was prepared, and an optical waveguide optical device was manufactured using the nonlinear optoelectronic compound, thereby obtaining an optical device having excellent reliability.

Wherein R ₁ and R ₂ are as described above.

The present invention is described in more detail as follows.

First, 4-halo benzaldehyde, dialkylamine, and sodium carbonate are added to hexamethyl-phosphoramide, stirred under a stream of nitrogen, cooled, extracted with a polar solvent, dried, and the solvent is removed. The digraphing process is carried out to obtain dialkylaminobenzaldehyde, or to react alkylaminobenzene and haloalki, and then to react the reaction product with POCl ₃ in dimethylformamide to obtain dialkylaminobenzaldehyde.

Then, 4-nitrophenylacetic acid was added to the flask, and piperidine was slowly added dropwise, and dialkylaminobenzaldehyde prepared above was added, stirred, cooled, left to stand, a replacement product was formed, filtered, recrystallized, and purified. To obtain the compound represented by the general formula (I).

The reaction scheme is described as follows.

The present invention prepared by the above-described method is excellent in compatibility and thermal stability of the nonlinear optoelectronic compound with the polymer as a polymer medium while maintaining a very large value of the electro-optic coefficient. In addition, the present invention uses a polyimide that can be thermally very stable at a glass transition temperature of more than 150 ℃ to prevent relaxation of the nonlinear optoelectronic compound as a polymer medium, the compatibility between the nonlinear optoelectronic compound and the polymer medium, It does not include the thermal stability and functional groups of the nonlinear optoelectronic compound, thereby minimizing light transmission loss.

As described above, the non-linear optoelectronic compound of the present invention may be used for fabricating various types of optical devices using conventional optical device manufacturing methods.

For example, an optical waveguide is manufactured by mixing a nonlinear optoelectronic compound with a polyimide, which is a polymer medium, in a predetermined ratio, scanning the silicon substrate on which chromium is deposited in advance, and then spin coating. The prepared optical waveguide is cured while being imidized by firing under specific conditions.

The present invention is explained in more detail in the following Examples, but is not intended to limit the scope of the present invention.

Example 1

(a) Synthesis of Dihexylaminobenzaldehyde

4-fluorobenzaldehyde (25 g, 0.2 mole), dihexylamine (37 g, 0.2 mole), and sodium carbonate (21.3 g, 0.2 mole) were added to 150 μm hexamethylphosphoramide (HMPA), followed by 110 ° C under nitrogen stream. After stirring for 4 days at the temperature of the reaction mixture, the reaction mixture is cooled, 1.5 L of water is added, extracted with toluene, dried over anhydrous MgSO ₄ , and toluene is removed. Dihexylaminobenzaldehyde is synthesized by performing a chromatographic process using the resulting highly viscous liquid with ethyl acetate and hexane as the developing solvent (1: 4).

Yield: 56%

(b) Synthesis of 4-dihexylamino-4'-nitrostelbene

4-nitrophenylacetic acid (7.24 g, 0.04 mol) is added to a 250 ml three-necked flask and 4 g of piperidine is slowly added dropwise. After dropping piperidine, dihexylaminobenzaldehyde (11.56 g, 0.04 mol) synthesized in (a) was added, and the reaction mixture was stirred at 100 ° C. for 3 hours, and then again at 130 ° C. for 3 hours. After stirring, the reaction mixture was cooled to room temperature and 150 ml of ethanol was added thereto.

Preventing the addition of ethanol yields a replacement product which is filtered to obtain a replacement product which is recrystallized and purified using ethanol to give 4-dihexylamino-4'-nitrostilbene.

Yield: 34%

Example 2

4-dihexyl-4 '-(nitro) stilbene prepared in Example 1 was mixed with polyimide (PIQ 2200, manufactured by Hitachi, Inc.) at 20wt%, injected onto a silicon substrate previously deposited with chromium, and then spincoated To prepare an optical waveguide.

At this time, the thickness of the optical waveguide is adjusted by the rotational speed, the thickness is inversely proportional to the rotational speed. The prepared optical waveguide is fired at 120 ° C. for 5 minutes and then cured while being imidized at 200 to 210 ° C. for about 3 hours.

Example 3

In a manner similar to that of Example 2, chromium for forming an electrode of the lower layer is deposited on a silicon substrate by a thermal evaporator, and the cladding layer is manufactured by spin coating using PIQ 2200 manufactured by Hitachi, Japan.

The core layer on the cladding layer is prepared by spin coating a mixture of 20 wt% diethylamino hexylsulfone stilbene prepared in Example 1 on PIQ 2200. The thin film core layer is dry-etched using 02-RIE (Reactive Ion Etching), but the etching pattern is etched by a photolithography process. The upper cladding layer was fabricated by spin coating PIQ 2200 on the fabricated waveguide in the same manner as the lower cladding layer, and then chromium-patterned the electrode by a lift-off method to manufacture an optical waveguide optical device.

[Examples 4 to 5]

The procedure was carried out in the same manner as in Examples 2 and 3 except that 4- (dihexyl) -4 '-(nitro) styrenebene was mixed in PIQ 2200 at 40 wt%.

[Examples 6-9]

It carried out similarly to Examples 2-5 except having used Ultradel 3112 or 4212 of Amico Corporation of USA as a polyimide.

As a result of measuring the electro-optical properties of the nonlinear optoelectronic compound prepared in Example 1 and the optical transmission loss ratio of the optical waveguide optical devices prepared in Examples 3, 5, 7, and 9, the mixing ratio of adding the nonlinear optoelectronic compound to the polyimide (10 ~ 40wt%), the light transmission loss was 1 ~ 2dB / cm, and had a decomposition temperature of 250 ℃ and sublimation temperature of 400 ℃.

The method of measuring the electro-optic properties and the light transmission loss rate is as follows.

The electro-optic coefficient was measured by the simple reflection method, that is, the method shown in FIG. The laser beam is incident at the back of the glass substrate at an angle of θ and is reflected from the metal (Au or Al) electrode. The polarization of the incident beam is 45 ° from the plane of incidence, and the magnitude of p and s waves is the same. The phase retardation (Ψsp) between the p and s waves is controlled by the SB compensator. The output laser intensity at the detector is given by

Where I _c is the half maximum intensity.

When the modulation voltage V = Vmsin? Mt is applied to the two electrodes, the change of phase angle? Is induced by? N due to the electro-optic effect. Further, δs due to the path change of the beam (p wave and s wave) due to the change of angle α is added. Therefore, the electrooptic coefficient r33 (˜3r31) is given by the following equation.

Is the incident wavelength in vacuum, n is the refractive index of the polymer, Im is the amplitude of the modulated intensity, I _c is the half width, and Vm is the amplitude of the applied modulation voltage. And n = n _e = n _o .

Also, as shown in FIG. 2, the optical transmission loss is obtained by guiding a laser beam into a waveguide using a high refractive index prism (GGG) as shown in FIG. After measuring the intensity of the beam emitted by the photodetector by using a high refractive index prism to measure the intensity of the beam emitted by the photodetector, the difference in the transmission of light per unit length (cm) ) Spread.

Claims (1)

In preparing an optical device using a host-guest system obtained by dispersing an organic optoelectronic compound in a polymer medium, a compound of the following general formula (I) is used as the organic optoelectronic compound, and a polyamic acid is used as the polymer medium. Method for manufacturing an optical waveguide optical device, characterized in that using. In the above formula, R ₁ and R ₂ are each an alkyl group of C _{6 to} C ₁₀ .