JP3224826B2 - Waveguide optical components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide type optical component comprising an optical waveguide and an input / output optical fiber used in the field of optical communication and the like.

[0002]

2. Description of the Related Art With the development of optical communication technology, in addition to conventional light sources, optical fibers, and photodetectors, various waveguide-type optical components such as an optical branching element, an optical switch, and an optical multiplexer / demultiplexer have been required. I have. This type of waveguide type optical component basically includes an optical waveguide array having a waveguide chip mounted thereon and an optical fiber array having input / output optical fibers mounted thereon. Now, the waveguide array generally has a structure in which a waveguide chip in which a waveguide is formed on a substrate such as silicon, glass, or sapphire is fixed to a housing with an adhesive or the like. The optical fibers arranged on a V-groove substrate or the like are fixed to a housing by an adhesive. As described above, in the optical fiber array and the optical waveguide array, the optical fiber and the optical waveguide chip are connected to the housing by the adhesive. Further, the optical waveguide array and the optical fiber array are generally connected by welding with an YAG laser or an adhesive, and are assembled as a waveguide type optical component. However, in the YAG laser method, a refractive index matching agent called a matching oil or a matching grease and an organic material are interposed at the connection portion between the optical fiber array and the waveguide array. Is interposed with an adhesive.

However, the adhesive layer, matching oil and mating grease interposed between the optical fiber array and the optical waveguide array, or between them, absorbs moisture in the presence of moisture, particularly under high temperature and high humidity conditions, and adheres over time. The force is reduced or the material deteriorates. Such a decrease in adhesive strength or deterioration of the material causes a decrease in light transmittance, separation of the fiber array from the waveguide array, and a displacement of the waveguide chip or the optical fiber in the optical fiber array or the waveguide array. This causes an increase in light loss of the waveguide type optical component. Such a problem significantly impairs the reliability of the optical component and, consequently, the reliability of the optical communication system, and cannot be neglected.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a waveguide type optical component having excellent long-term reliability.

[0005]

According to the present invention, an optical waveguide array in which an optical waveguide is adhesively fixed to a housing and an input / output optical fiber are adhesively fixed to the housing in order to improve the moisture and heat resistance of the optical component. In a waveguide type optical component in which the optical fiber array is connected to the optical fiber array with the optical axes aligned, a coating made of metal or carbon is formed on the connection portion or the outer periphery.

In the present invention, the method for producing a metal film or a carbon film is not particularly limited. For example, in order to form a carbon film by a high-temperature plasma method, a monohydric alcohol such as methanol or ethanol, a polyhydric alcohol such as ethylene glycol, or an aromatic compound can be used. Also, a diamond-like carbon film obtained by a low-temperature plasma method using hydrocarbon as a raw material, α
It may be a graphite-like carbon film obtained by a CVD method using -chloro-o-xylene or the like as a raw material, or a carbon film obtained by evaporating carbon with an electron beam in a vacuum. Further, a sputtering method, a dipping method, or the like can be applied to the metal film. The kind of metal is not particularly limited, but relatively soft materials such as metals and alloys such as tin, aluminum and nickel are suitable. Further, the thickness of the coating of the present invention is not particularly limited. However, if the thickness is large, the light transmittance at a low temperature may be adversely affected depending on the type of the coating material. For this reason, it is desirable that the thickness of the coating film is 10 μm or less.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific embodiment of the present invention using a quartz optical waveguide formed on a silicon substrate as an optical waveguide will be described. A silica-based optical waveguide has excellent refractive index matching with a silica-based optical fiber and can provide a practical waveguide-type optical component, but the present invention is not limited to only such a silica-based optical waveguide. Needless to say.

Embodiment 1 FIG. 1 is a view showing a first embodiment of the present invention, wherein 1 is an optical waveguide array, 2 and 3 are optical fiber arrays, 4, 5 are adhesive layers, 6, 7, and Reference numerals 8 and 9 denote optical fibers. The optical waveguide chip used here is a quartz-based multimode optical waveguide having a core size of 50 μm × 50 μm formed on a silicon substrate having a thickness of 0.7 mm, and is fixed to a housing made of silica glass with an adhesive, The optical waveguide array 1 is configured. The optical fiber arrays 2 and 3 are each formed by fixing a quartz-based multimode optical fiber having a core diameter of 50 μm to a quartz glass housing via a V-groove substrate with an adhesive. The waveguide array and the optical fiber array are connected by an ultraviolet-curable adhesive to form a waveguide-type optical component. Next, a high-temperature plasma state was generated by DC arc discharge while flowing a gas in which methanol was mixed with argon gas at a ratio of several percent. The alcohol gas was decomposed by the high-temperature plasma to generate carbon, and a film of the generated carbon was formed on the outer periphery of the waveguide type optical component.

The optical component having the carbon coating thus produced was placed together with the optical component having no coating in an atmosphere at a temperature of 70 ° C. and a relative humidity of 90% for comparison, and subjected to a moist heat test. FIG. 2 is a diagram showing the results of the moist heat resistance test. The optical component having the carbon coating indicated by A in FIG.
Even after the lapse of 00 hours, the loss fluctuation was 0.1 dB or less.
On the other hand, the optical component without the coating (B in the figure) is about 5
The loss increased sharply after 0 hours. In addition, when a heat cycle test of the coated parts was performed, it was found that -20 to 7
The loss fluctuation in the temperature range of 0 ° C. was 0.1 dB or less.

Embodiment 2 Next, a second embodiment of the present invention will be described. A silica-based single-mode optical waveguide chip consisting of a silica-based glass core having a cross-sectional dimension of 8 μm × 8 μm embedded in a 50-μm-thick silica-based glass clad layer on a silicon substrate is attached to a Pyrex glass housing with an adhesive. It was fixed to form a waveguide array. Further, a silica-based single-mode optical fiber having a core diameter of 10 μm was fixed to a Pyrex glass housing via a V-groove with an adhesive to form a fiber array. Next, the waveguide array and the optical fiber array were connected with an ultraviolet-curable adhesive to obtain a waveguide optical component.

Next, a tin film was coated on the periphery of the component by a sputtering method, and a moist heat resistance test was performed. An optical component having a tin film coating has a loss variation of 0.1 d even after 500 hours.
B or less. In contrast, the loss of the optical component without the coating increased sharply after about 50 hours. Also,
A heat cycle test of the coated parts revealed that-
0.1 dB loss fluctuation in the temperature range of 20 to 70 ° C
It was below.

Embodiment 3 Next, a third embodiment of the present invention will be described. A silica-based single-mode optical waveguide chip consisting of a silica-based glass core having a cross-sectional dimension of 8 μm × 8 μm embedded in a 50-μm-thick silica-based glass clad layer on a silicon substrate is attached to a Pyrex glass housing with an adhesive. It was fixed to form a waveguide array. A silica-based single-mode optical fiber having a core diameter of 10 μm was fixed to a Pyrex glass case via a V-groove with an adhesive to form a fiber array. Next,
The waveguide array and the optical fiber array were connected by an ultraviolet curing adhesive.

Next, a carbon film was formed on the connection between the waveguide array and the optical fiber array in the same manner as in Example 1, and a wet heat resistance test was performed. The loss fluctuation of the optical component having the carbon film coating was 0.1 dB or less even after 500 hours. In contrast, an optical component without a coating is
The loss increased sharply after about 50 hours. In addition, a heat cycle test of the coated parts showed that
The loss fluctuation in the temperature range of -70 ° C was 0.1 dB or less.

Embodiment 4 FIG. 3 is a view showing a fourth embodiment of the present invention, wherein 1 is an optical waveguide array, 2, 3 are optical fiber arrays, 6, 7, and
Reference numerals 8 and 9 denote optical fibers. The optical waveguide chip used here is a quartz-based multimode optical waveguide having a core size of 50 μm × 50 μm formed on a silicon substrate having a thickness of 0.7 mm, which is bonded to a Kovar housing with an epoxy-based adhesive. Thus, a waveguide array was obtained. In addition, the fiber array uses a silica-based multimode optical fiber having a core diameter of 50 μm,
It is connected to the Kovar housing by epoxy-based bonding via a V-groove. The waveguide array and the fiber array were connected by a YAG laser.

Next, in the same manner as in Example 1, a carbon film was coated on the outer periphery of the component, and a temperature of 70 ° C. and a relative humidity of 9 were applied.
It was set in an atmosphere of 0% and its loss change was measured.
FIG. 4 is a diagram showing the results of this moisture and heat resistance test. A in the figure
In the optical component having the carbon film coating indicated by, the loss variation was 0.1 dB or less even after the elapse of 1000 hours. In contrast, the loss of the optical component without the coating (B in the figure) gradually increased after about 500 hours. When a heat cycle test was performed on the coated parts,
Was less than 0.1 dB in the temperature range.

Embodiment 5 A quartz-based glass single-mode optical waveguide chip having a quartz-based glass core having a cross section of 8 μm × 8 μm embedded in a 50-μm-thick quartz-based glass clad layer on a silicon substrate was bonded with an adhesive. It was fixed to a Kovar housing to form a waveguide array. A silica-based single mode optical fiber having a core diameter of 10 μm was fixed to a Kovar housing via a V-groove with an adhesive to form a fiber array. Next, the waveguide array and the optical fiber array were connected by a YAG laser.

Next, a tin film was coated on the outer periphery of the component by a sputtering method, and a moist heat resistance test was performed. An optical component having a tin film coating has a loss variation of 0.1 even after 1000 hours.
dB or less. On the other hand, the loss of the optical component without the coating gradually increased after about 500 hours.
When a heat cycle test was performed on the coated parts, the loss fluctuation in the temperature range of -20 to 70 ° C. was 0.1%.
It was 1 dB or less.

EXAMPLE 6 A silica-based glass single-mode optical waveguide chip comprising a silica-based glass core portion having a cross-sectional dimension of 8 μm × 8 μm embedded in a 50 μm-thick silica-based glass clad layer on a silicon substrate was bonded with an adhesive. It was fixed to a Kovar housing to form a waveguide array. A silica-based single mode optical fiber having a core diameter of 10 μm was fixed to a Kovar housing via a V-groove with an adhesive to form a fiber array. Next, the waveguide array and the optical fiber array were connected by a YAG laser.

Next, a carbon film was formed on the connection between the waveguide array and the optical fiber array in the same manner as in Example 1, and a wet heat resistance test was performed. The optical component having the carbon film coating had a loss variation of 0.1 dB or less even after the elapse of 1000 hours. On the other hand, an optical component having no coating has about 5
After the lapse of 00 hours, the loss gradually increased. In addition, a heat cycle test of the coated parts showed that
The loss fluctuation in the temperature range of -70 ° C was 0.1 dB or less.

In the above-described embodiment, two ends are provided at the end of the optical fiber waveguide.
Although an example in which optical fibers are connected one by one has been described, the present invention is not limited to this.
It goes without saying that the present invention can be applied to a case where a six-core optical fiber array or the like is collectively connected to an eight-row or sixteen-row optical waveguide array or the like.

[0021]

As described above, in the waveguide type optical component of the present invention, the connecting portion or the outer periphery is coated with a film of carbon, metal, or the like. Can be suppressed from being deteriorated. Therefore, the optical component of the present invention can be expected to greatly contribute to the improvement of the performance of the optical communication system and economical improvement.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a structure of a waveguide type optical component according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the results of a moisture and heat resistance test of the waveguide optical component manufactured in the first example of the present invention.

FIG. 3 is a perspective view showing a structure of a waveguide type optical component according to a fourth embodiment of the present invention.

FIG. 4 is a diagram showing a result of a moisture and heat resistance test of the waveguide type optical component manufactured in the first example of the present invention.

[Explanation of symbols]

 1 Optical waveguide array 2, 3 Optical fiber array 4, 5 Adhesive 6, 7, 8, 9 Optical fiber

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-77704 (JP, A) JP-A-60-7401 (JP, A) JP-A-2-308208 (JP, A) JP-A-57- 198405 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 6/30

Claims (1)

(57) [Claims] 1. An optical waveguide array comprising an optical waveguide array having an optical waveguide bonded and fixed to a housing and an optical fiber array having input / output optical fibers bonded and fixed to the housing so that their optical axes are aligned and connected. in the wave-type optical components, diamond La formed by high-temperature plasma method or a low temperature plasma process in the connection part or the outer periphery of the waveguide-type optical components
Waveguide type optical component, wherein the coating of Ik carbon film is formed.