JP3358168B2 - Dendrimer optical waveguide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide used as an optical component for optical interconnection of computers and exchanges, for optical LAN wiring, and for optical subscriber equipment.

[0002]

2. Description of the Related Art Optical components having a polymer base material, particularly polymer optical waveguides, include PMMA (polymethyl methacrylate) optical waveguides, silicone optical waveguides, polyimide optical waveguides, polycarbonate optical waveguides, and photocurable resin optical waveguides. Waveguides, thermosetting resin optical waveguides, and the like have been developed. Some of these polymer optical waveguides have already begun to be put into practical use as overwhelmingly compact alternatives to fiber components and lower cost alternatives to glass-based optical waveguide components. Furthermore, polymer optical waveguides are opening up new fields as key devices for optical connection, making use of the low-temperature processability and mechanical flexibility inherent to polymers. For the development trend of polymer optical waveguides, see “Polymer”, April 1994, 27th edition.
Detailed on one page. As mentioned above, polymer optical waveguides are attracting attention as small and inexpensive alternatives to optical fiber components and glass optical waveguide components, and as new optical components that take advantage of the characteristics of polymers. There are some issues to be overcome. The most essential issue among them is to satisfy heat resistance without lowering workability and optical characteristics. Table 1 shows the optical characteristics, processability,
As for heat resistance, the performance of a conventional polymer optical waveguide is qualitatively compared.

[0003]

[Table 1] Table 1 ─────────────────────────────────── Light transmittance Refractive index isotropic processing And flexibility Heat resistance ＰＭ PMMA optical waveguide ◎ ◎ ◎ △ Polyimide light guide Waveguide 〇 △ △ ◎ Crosslinkable resin optical waveguide △ 〇 〇 ─────────────────────────────────── ───────────────────────────────────

It is clearly shown that the heat resistance of an optical waveguide made of a high molecular weight linear polymer tends to be inconsistent with the refractive index isotropic property and workability. Generally speaking, the rigid structure of the polymer chain, which is essential for ensuring heat resistance,
It increases the birefringence and reduces the flexibility of the molecular chains. This tendency is remarkable in the polyimide optical waveguide. vice versa,
The use of a PMMA optical waveguide having excellent transparency, refractive index isotropy and processability is significantly limited unless there is a significant improvement in heat resistance. On the other hand, in the case of an optical waveguide made of a resin containing an acrylic / epoxy crosslinkable oligomer as a main component, no extreme trade-off in characteristics is observed, but the fraction of aliphatic chains is inevitably large. It is difficult to increase the light transmittance as much as possible because of the fact that it requires an additive and the like.

[0005]

As described above, a polymer optical waveguide satisfying all of the required various properties at a high level at the same time has not been obtained. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a new polymer optical waveguide that guarantees heat resistance without deteriorating workability and optical characteristics.

[0006]

SUMMARY OF THE INVENTION To summarize the present invention, a first invention of the present invention relates to an optical waveguide and has the following formula (Formula 1):

[0007]

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A compound represented by the formula (Me represents a methyl group) is used as a building block, and the following formula (Formula 2), Formula (Formula 3) or Formula (Formula 4) (Me in each formula) Is
Both mean a methyl group):

[0009]

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[0010]

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[0011]

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It is characterized by comprising an ether ketone dendrimer represented by the formula: The second invention of the present invention relates to another optical waveguide, and is a one-pot condensed polymer of a building block represented by the following formula (Formula 1).

[0013]

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It is characterized by comprising an ether ketone hyperbranched polymer represented by the formula: In the present invention, in the case of the core-clad optical waveguide, the core or the clad is formed by any one of the above formulas (Formula 2), Formula (Formula 3), Formula (Formula 4), and Formula (Formula 5). It may be.

According to the present invention, a dendrimer is used as a base material of a polymer optical waveguide in order to provide a new polymer optical waveguide satisfying thermal stability without deteriorating workability and optical characteristics. It is characterized by the following.

A dendrimer is a highly branched structure in which monomers having a Y-shaped structure are stacked in a dendritic pattern over many generations while forming a concentric layer around one core molecule. It is a generic term for spherical macromolecules of uniform molecular weight. How to grow nuclei from the center to the outside is called Divergent Grouse.
Conversely, the method of making dendrimers from the outside toward the center is called convergent growth. Regardless of what was synthesized by any method, the molecular chains are filled without voids,
Bending of molecular chains and entanglement of molecular chains, which are generally caused in ordinary polymers, are regulated in advance. As a result, the melt viscosity is lower than that of a linear polymer having the same molecular weight while maintaining the heat resistance. The industrial meaning of the above features lies in the fact that insoluble and infusible polymers can be injection-molded, and it has been sought to enter the engineering plastic market for heat-resistant dendrimers that can be injection-molded. On the other hand, in the field of fine chemicals, dendrimers are attracting attention as artificial matrices whose higher-order structures are uniquely determined. In particular, there is an active movement to apply dendrimers as protein analogs to drug delivery systems. that's all,
For the recent trend of dendrimers, see “Nikkei Science”, July 1995, p. 38, “New Materials”, 19
August 1994, p. 75, Chemical Engineering News (Chem. Eng. News), November 1993, p. 51, etc. The present inventors have found that a dendrimer having the above features is extremely suitable as a polymer optical waveguide material excellent in processability while maintaining thermal stability comparable to a heat-resistant polymer. It was completed.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically. First, the dendrimer optical waveguide of the present invention will be described in detail. The present invention is an optical waveguide characterized by being composed of an ether ketone dendrimer [(Chem. 2), (Chem. 3) or (Chem. 4)] already synthesized by Morikawa et al. For details on synthesis, see Macromolecules.
omolecules), Vol. 26, pp. 6324-6329 (1
993). However, when used as an optical waveguide material, the synthesis described in the paper is not sufficient, and colored impurities must be removed at each stage of the synthesis by high-purity purification such as column chromatography. In addition, for the ether cleavage reaction and the like in which colored impurities are most likely to be generated, consideration must be given to selecting reaction conditions that are as mild as possible. Next, the present invention also provides an optical waveguide comprising a dendritic ether ketone-based hyperbranched polymer [formula (5)] synthesized by Miller et al. Details of the synthesis are described in Journal of American Chemical Society (J. Am. Chem. Soc.), Vol. 115, 356-
357 (1993). Also in this system, a special synthesis operation and purification operation for high purification are required as in the above-mentioned ether ketone dendrimer.
Further, it is extremely important to make the molecular weight uniform by a method such as fractional precipitation in order to construct an optical waveguide having excellent transparency.

The ether ketone-based dendrimer and the dendritic ether ketone-based hyperbranched polymer are (1) moldable as an optical waveguide, (2) have ultra-low loss optical transparency, and (3) optical waveguide. It has been clarified for the first time by the present invention that the isotropic refractive index is maintained.

[0019]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 An ether ketone dendrimer (which is represented by the formula (Chemical formula 2), hereinafter abbreviated as G2) easily turned into a transparent film by spin coating from a solution. The birefringence of this G2 film at a wavelength of 1.3 μm was measured by a prism coupling method and found to be about 0.001. After confirming that the birefringence was small in this way, G2 was used as an ethoxyethyl acetate solution, and 0.2 μm
, And spin-coated on a glass substrate to obtain a G2 transparent film having a thickness of 3.6 μm. The optical waveguide loss of the slab-type optical waveguide manufactured as described above was measured. Laser light having a wavelength of 633 nm was incident on the film by prism coupling. The state of the optical waveguide was observed using an infrared video camera, and the intensity of the guided light was estimated from the intensity of the scattered light at each waveguide distance. FIG. 1 shows the dependence of the intensity of the guided light measured in this way on the guided distance. The loss was determined from the slope. The loss value was 2.1 dB / cm. Next, the same measurement was performed with the incident light wavelength set to 1.3 μm, and the result of FIG. 2 was obtained. The loss value was 1.2 dB / cm. That is, FIG. 1 is a diagram illustrating the dependence of the guided light intensity of the G2 slab type optical waveguide at a wavelength of 1.3 μm on the guided distance.
FIG. 2 is a graph showing the dependence of the intensity of the guided light of the G2 slab type optical waveguide at a wavelength of 633 nm on the guided distance.
1 and 2, the vertical axis represents the intensity of guided light (arbitrary unit), and the horizontal axis represents the optical waveguide distance (cm).

FIG. 3 is a view showing a visible / near infrared absorption spectrum of the G2 spin-coated film. That is, FIG. 3 is a view showing a visible / near infrared absorption spectrum of a G2 cast film prepared from a methylene chloride solution. Note that FIG.
, The vertical axis represents absorbance (arbitrary unit), and the horizontal axis represents wavelength (n
m). As shown in FIG. 3, most of the absorption extending from the visible region to the near-infrared region comes from impurities containing a tan phenol structure. Therefore, G2 was synthesized again under the synthesis conditions under which the purification by column chromatography was sufficiently performed at each stage of the synthesis, and the generation of impurities including the phenol structure was suppressed as much as possible, and the optical waveguide loss value was obtained. , 633 nm, and 1.3 μm.
It became 5 dB / cm or less.

Examples 2 and 3 An ether ketone-based dendrimer [compound represented by the formula (Chemical Formula 3)] synthesized in an impurity-free manner according to Example 1 (G
3) and the same dendrimer [those represented by the formula (Formula 4)]
For (G4), a slab-type optical waveguide was manufactured, and low birefringence and low-loss waveguide equivalent to G2 were confirmed. Further, regarding these, the lower clad thickness: 20 μm, the core diameter: 8
A channel-type optical waveguide having a size of 8 μm × 8 μm and an upper cladding thickness of 15 μm was manufactured by using photolithography and dry etching. As the clad material, an ultraviolet curable resin prepared such that the relative refractive index difference with respect to the core material, dendrimer, was 0.3% was used. When the optical waveguide loss values of these channel-type optical waveguides were determined, both were 0.5 dB / cm or less under the single mode condition at a wavelength of 1.3 μm. In particular, the loss of the most advanced G4 channel type optical waveguide of the generation did not increase even at 120 ° C.

Example 4 From a building block [a compound represented by the formula (1)], a dendritic hyperbranched polymer [a compound represented by the formula (5)] synthesized by one-pot polycondensation was subjected to fractional precipitation. Purified and reduced dispersion. A spin-coated film was prepared from a chlorobenzene solution, and the birefringence was measured. Example 1
The birefringence was slightly larger than that of the ether ketone dendrimer synthesized by the regular convergent method in Nos. 3 to 3. A channel-type optical waveguide having the hyperbranched polymer as a core was manufactured according to Examples 2 and 3. At a wavelength of 1.3 μm, single-mode waveguide with a loss of about 0.5 dB / cm was possible. Loss is 120 ° C
Also did not increase.

[0024]

As described above, the dendrimer optical waveguide (general term including hyperbranched polymer) according to the present invention simultaneously has high optical properties, workability and heat resistance which are the main requirements for the optical waveguide. It is satisfactory at the level, and as a directional coupler or an optical waveguide for optical interconnect, which was hesitant to apply in the conventional polymer optical waveguide,
Widely available. More generally, the dendrimer optical waveguide of the present invention is widely and stably used as a low-cost and high-performance optical component for optical interconnection of computers and exchanges, for optical LAN wiring, and for optical subscriber equipment. Can be used. That is, there is an advantage that each system of the optical interconnection, the optical LAN, and the optical subscriber can be configured by using the dendrimer optical waveguide as a key device. In addition, the dendrimer has a highly symmetrical structure and a highly branched and densely packed spherical structure, so that the distance between the center and the outermost edge of the dendrimer molecule and the distance between the dendrimer molecules are precisely defined, so that identification within the molecule is possible. If, for example, an optical amplifier function substance, EL substance, photo-charge separation substance, etc. can be held at the position, the photophysical
It is also possible to develop this dendrimer optical waveguide as a new type of optical waveguide type optical functional device utilizing photochemical behavior. Therefore, the present invention can be widely applied to fields such as optical communication, optical information processing, and optics.

[Brief description of the drawings]

FIG. 1 is a diagram showing the dependence of the guided light intensity of a G2 slab type optical waveguide at a wavelength of 1.3 μm on the guided distance.

FIG. 2 is a graph showing the dependence of the intensity of guided light of a G2 slab type optical waveguide at a wavelength of 633 nm on the guided distance.

FIG. 3 is a view showing a visible / near infrared absorption spectrum of a G2 cast film prepared from a methylene chloride solution.

Continuation of the front page (56) References JP-A-6-157727 (JP, A) JP-A-8-231864 (JP, A) JP-A-6-93097 (JP, A) Table 2000-511219 (JP, A) A) Table 9-510489 (JP, A) Table 8-505899 (JP, A) Table 8-505658 (JP, A) (58) Fields surveyed (Int. Cl. ⁷ , DB name) ) G02B 6/12 C08G 65/00

Claims (4)

(57) [Claims] 1. The following formula (Formula 1): (Wherein Me represents a methyl group), a compound represented by the following formula (Formula 2), Formula (Formula 3), or Formula (Formula 4) (where Me in each formula is An optical waveguide comprising an ether ketone-based dendrimer represented by the following formula: Embedded image Embedded image Embedded image 2. A method according to claim 1, wherein at least the core and a clad surrounding the core and having a lower refractive index than the core are provided on the substrate, and the core or the clad is a compound represented by the formula (1) as a building block. The optical waveguide according to claim 1, comprising an ether ketone-based dendrimer represented by the following formula (2), formula (3), or formula (4). 3. A one-pot condensed polymer of a building block represented by formula (1), which is represented by the following formula (5): An optical waveguide comprising an ether ketone hyperbranched polymer represented by the formula: 4. At least a core and a clad surrounding the core and having a lower refractive index than the core are provided on the substrate, and the core or the clad is a one-pot condensation polymer of a building block represented by the formula (Formula 1). 4. The optical waveguide according to claim 3, comprising an ether ketone-based hyperbranched polymer represented by the following formula (5).