JP2003161845A - Optical fiber sheet and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber sheet which is applied to optical fiber amplifier or the like, which can control the fluctuation in wavelength characteristics with respect to the temperature change in an optical fiber which has the temperature dependent characteristics, and which is very compact. <P>SOLUTION: This optical fiber sheet (1) is characterized in that an optical fiber (2) and a heating wire (3) for heating the optical fiber (2) are laid on a substrate (4). Also, on the substrate (4), a temperature sensor (6), a fiber temperature adjusting circuit (7), an electrode for energization (8) or the like can be provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber sheet applied to an optical fiber amplifier or the like, and relates to a technique capable of controlling fluctuation of wavelength characteristics with respect to environmental temperature change of an optical fiber having temperature dependence.

[0002]

2. Description of the Related Art Conventionally, an optical amplifying device utilizing the optical amplifying action of an optical fiber doped with a rare earth element has been put into practical use. For example, when signal light having a wavelength of 1550 nm band is used as the signal light, an erbium-doped fiber (hereinafter, referred to as “ED
"F". ) Is used. Further, the optical amplification factor of such a rare earth-doped fiber is proportional to the so-called concentration length product, which is the product of the concentration of the element to be doped and the length of the optical fiber. Therefore, in order to improve the optical amplification factor, it is advantageous to increase the length of the optical fiber.

On the other hand, practical optical amplification elements are required to be small and thin. Therefore, for example, Japanese Patent Laid-Open No.
Japanese Patent Laid-Open No. 211918 discloses a technique of arranging and holding an optical fiber of a predetermined length on a substrate made of plastic or the like.

Further, the optical amplification action of the EDF has temperature dependence, and therefore the EDF has a characteristic that the optical amplification characteristic varies depending on the ambient temperature in which it is used. Therefore, if the optical amplification element is made smaller and thinner, there is a problem that the fluctuation of the environmental temperature greatly affects the optical amplification characteristics of the element.

In order to solve this problem, a technique for adjusting the EDF temperature to a constant level has been disclosed. For example, Japanese Patent Application Laid-Open No. 2001-257402 discloses a technique of sandwiching a substrate on which an EDF is placed with a substrate including a temperature control element such as a Peltier element. This technique is intended to heat or cool the EDF by energizing the temperature adjusting element to keep the temperature of the EDF at a predetermined temperature and obtain a desired wavelength characteristic.

[0006]

However, in the above-mentioned prior art, in order to adjust the temperature of the EDF arranged on the substrate, a temperature control element formed on a separate substrate is required, and the optical fiber is required. There is a problem that the amplifier itself becomes relatively large. Therefore, when a large number of such optical fiber amplifiers are combined into a component, there is a problem that they cannot be densely mounted.

Further, since the temperature adjusting element composed of a Peltier element or the like is large compared to the surface area of the optical fiber arranged on the substrate, there is a problem that the cost of the optical fiber amplifier itself increases.

The present invention has been made in view of the above points, and an object thereof is to obtain a stable optical amplification characteristic in an optical fiber sheet using an optical fiber having temperature dependence such as EDF. , To provide an extremely compact optical fiber sheet.

[0009]

The invention according to claim 1 is
It is an optical fiber sheet characterized in that a heating wire for heating the optical fiber is laid on the substrate together with the optical fiber. With such a configuration, the temperature of the heating wire is directly transmitted to the optical fiber, and it is not necessary to separately form the temperature adjusting element. Therefore, the optical fiber sheet can be made extremely compact.

The invention according to claim 2 is the optical fiber sheet according to claim 1, wherein a temperature sensor for detecting the temperature of the optical fiber is provided on the substrate. It is a sheet. With such a configuration, there is no need for a separate temperature detecting device,
The optical fiber sheet can be made extremely compact. .

The invention according to claim 3 is the optical fiber sheet according to claim 1 or 2, wherein the amount of electricity to the heating wire is controlled on the substrate so that the optical fiber has a predetermined temperature. The optical fiber sheet is provided with a fiber temperature adjusting circuit. With such a configuration, the amount of electricity supplied to the heating wire is properly controlled, and the optimum temperature of the optical fiber is maintained. Furthermore, since a separate temperature control device is not required, the optical fiber sheet can be made extremely compact.

The invention according to claim 4 is the optical fiber sheet according to any one of claims 1 to 3, wherein an energizing electrode for energizing the heating wire is provided on the substrate. This is an optical fiber sheet.
With such a configuration, the temperature adjusting function of the optical fiber can be obtained simply by inserting it into a socket or the like that engages with the electrode.

The invention according to claim 5 is the optical fiber sheet according to any one of claims 1 to 4, wherein the substrate is provided with a heat radiation effect. With such a configuration, even if the temperature is excessively raised by the heating wire, the residual heat is quickly dissipated, so that the temperature of the optical fiber can be smoothly adjusted.

The invention according to claim 6 relates to a method for manufacturing an optical fiber sheet according to the present invention, which comprises a step of laying an optical fiber on a substrate, and an electric wire for heating the optical fiber on the substrate. And a step of laying a heating wire, which is a method of manufacturing an optical fiber sheet.

[0015]

Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

<< Embodiment 1 >> FIG. 1 is a schematic plan view of an optical fiber sheet (1) according to the present embodiment.

The optical fiber (2) used in this embodiment is an ED made of quartz having a core doped with erbium.
F having an outer diameter of 250 μm. On the other hand, a stainless steel thin wire having an outer diameter of 60 μm is used as the heating wire (3). The outer diameters of the optical fiber (2) and the heating wire (3) are not limited to the above, but the outer diameter of the optical fiber (2) is [D] and the outer diameter of the heating wire (3) is [d]. ], It is preferable that the value of d / D is about 0.2 to 0.3.

As the material of the heating wire (3), other than stainless steel, nichrome (Ni-Cr) and Kanthal (Fe-Cr-) which are generally used as a material for the heating wire are used.
Al), tungsten, molybdenum, tantalum, nickel, etc., as well as gold, silver, copper, platinum, aluminum and the like used as the conductor. in this case,
Low resistivity material is suitable, 10 μm · cm (0 ° C)
The following materials are practical.

The optical fiber (2) is wired in a coil shape together with the heating wire (3) on a substrate (4) made of plastic or the like. The optical fiber (2) and the heating wire (3) are wound in a track shape in a counterclockwise direction from one end of the substrate (4) as a starting point, and depending on the required length, 1
After winding a plurality of times or a plurality of times, the winding direction is changed into an S shape at the center of the track shape, and the winding is laid clockwise along the already laid optical fiber (2). It will be the end point. As described above, the optical fiber (2) is wound around the coil, so that the length of the optical fiber can be increased on the substrate having a predetermined area. Therefore, in the case of the optical amplifier using the EDF, the so-called density length product increases, and the optical amplification factor can be improved.

A protective film layer (5) is laminated and fixed on the upper surface of the optical fiber (2) and the heating wire (3) thus wound and laid.

The wiring method of the optical fiber (2) and the heating wire (3) in the optical fiber sheet (1) is as follows. First, the heating wire (3) is laid and then the optical fiber (2) is The method of wiring along 3) is suitable. As shown in FIG. 2, according to this method, one optical fiber (2) is laid between two heating wires (3), and any one of the heating wires (3) is sandwiched. Another optical fiber (2) is laid in this way. Alternatively, as shown in FIG. 3 (a), two optical fibers (2) are laid between two heating wires (3), or as shown in (b), one heating wire is used. (3) is sandwiched between two optical fibers (2),
The other heating wire (3) can be wired so as to ride on the two optical fibers (2). 2 more
Two optical fibers (2) can be laid so as to sandwich the heating wire (3), but in this case, the heating wire (3) is insulated by an enamel coating or the like. is necessary.

According to another method, it is possible to first lay the optical fiber (2) and then lay the heating wire (3). In this case, one or two heating wires (3) are placed in the valley where the two optical fibers (2) are in contact. In that state, it is preferable that the heating wire (3) is dropped onto the substrate (4) from between the optical fibers (2) by applying a pressing force from above. By thus dropping the heating wire (3) between the optical fibers (2), the relatively thin heating wire (3) is covered by the optical fiber (2) and the disconnection due to an external force can be prevented.

According to yet another method, the optical fiber (2)
It is also possible to lay the and heating wire (3) at the same time. In this case, a wire arranging device provided with a delivery port through which the optical fiber (2) and the heating wire (3) can be discharged in parallel is used.

Alternatively, the optical fiber (2) and the heating wire (3)
It is also possible to wire the wires that are previously combined into one. In this case, it is preferable that the heating wire (3) and the optical fiber (2) are integrated so that they are in contact with each other so as not to hinder the heat conduction from the heating wire (3) to the optical fiber (2). Specifically, it is possible to coat the optical fiber (2) and the heating wire (3) with an enamel resin or the like so as to be integrated. Further, the heating wire (3) may be spirally wound around the optical fiber (2) to be integrated.

<< Embodiment 2 >> FIG. 4 shows a schematic plan view of an optical fiber sheet (1) according to the present embodiment. The optical fiber (2) used in the present embodiment is a quartz EDF having a core doped with erbium and having an outer diameter of 25.
It is 0 μm. Also, the heating wire (3) has an outer diameter of 6
A 0 μm stainless steel wire is used.

Substrate (4) used in the embodiment
Is made of a material having a high heat insulating property. An adhesive layer (10) is formed on the substrate (4), and the optical fiber (2) and the heating wire (3) are laid on the coil on the adhesive layer (10). These optical fiber (2) and heating wire (3) are
Starting from one end of the substrate (4), wound in a counterclockwise direction in a track shape, wound one or more times, and then changing the winding direction into an S shape at the center of the track shape, It is wound around the optical fiber (2) already installed in a clockwise direction and reaches the starting point position to reach the end point. A protective film layer (5) is laminated and fastened from the upper surfaces of the optical fiber (2) and the heating wire (3) thus wound and installed.
Further, a heat insulating layer (11) is laminated and fixed on the upper surface of the film layer (5).

An energizing electrode (8) is formed on the peripheral portion of the substrate (4). A wire (9) communicates with the energizing electrode (8) to a fiber temperature adjusting circuit (7) provided at a predetermined portion of the substrate (4). The fiber temperature control circuit (7) processes information about the temperature of the optical fiber (2) detected by a temperature sensor (6) fixed along the optical fiber (2) as shown in FIG. By controlling the electric power supplied to the heating wire (3), the temperature of the optical fiber (2) can be maintained in a desired temperature range.

As the temperature sensor (6), a thermistor or a thermocouple is used. Further, the temperature sensor (6) may detect a change in the resistance value of the heating wire (3) due to a change in temperature as a change in current or voltage.

The fiber temperature adjusting circuit (7) has an algorithm shown in FIG. The algorithm receives information about temperature from the temperature sensor (6), compares the temperature with a preset reference value, and controls the power supply to the heating wire (3) based on the result. is there. In addition, as shown in (b), the temperature sensor (6)
Information about the current and voltage of the heating wire (3) is input from, the resistance value of the heating wire (3) is calculated from the information, and the resistance value is compared with a reference value corresponding to a preset optimum temperature, The power supply to the heating wire (3) may be controlled based on the result.

The outer shape of the fiber temperature control circuit (7) is preferably a thin and small chip-like one because it is installed on the substrate (4).

According to this embodiment, the substrate (4) is made of a material having a high heat insulating property, and the heat insulating layer (11) is formed on the upper surface of the film layer (5). The fiber (2) and the heating wire (3) are less susceptible to changes in environmental temperature, and it becomes easy to maintain the temperature of the optical fiber (2) within a desired temperature range.

By forming the adhesive layer (10) on the substrate (4), the optical fiber (2) and the heating wire (3) can be attached to the substrate (4). The subsequent step of coating the film layer (5) is facilitated.

Furthermore, by forming the current-carrying electrode (8) on the substrate (4), it becomes possible to use a current-carrying socket or the like that engages with the electrode. Therefore, the temperature adjustment function can be imparted to the optical fiber sheet (1) only by inserting the energizing electrode (8) into the energizing socket, and a complicated wiring work is not required.

<< Embodiment 3 >> As the present embodiment, it is possible to add a heat dissipation effect to the substrate (4) in the above-mentioned Embodiment 2. As a method of adding heat dissipation, it is possible to use a thin plate made of metal with high thermal conductivity for all or part of the substrate (4), or to provide a heat dissipation structure on the back surface of the substrate (4). is there. Furthermore, it is also possible to add a heat radiation effect by using a cooling element controlled by the fiber temperature adjusting circuit (7).

As described above, by adding the heat radiation effect to the substrate (4), if the heating by the heating wire (3) exceeds the optimum temperature of the optical fiber (2), the heating wire (3) ), The heat is rapidly dissipated and the temperature of the optical fiber (2) can be lowered. Further, by using the cooling element, the temperature of the optical fiber (2) can be quickly lowered even when the environmental temperature exceeds the optimum temperature of the optical fiber. Therefore,
The temperature of the optical fiber (2) can be adjusted more precisely.

<Fourth Embodiment> A preferred embodiment of the method for producing the optical fiber sheet (1) according to the present invention will be described.

Optical fiber sheet (1) according to the present embodiment
The manufacturing method of the method comprises the step of laying an optical fiber (2) on a substrate (4) and the optical fiber (2) on the substrate (4).
And a step of laying a heating wire (3) for heating the.

In this manufacturing method, a conventionally used fiber wiring device is used. The fiber wiring device comprises a wiring head having a fiber outlet, and a stage on which a substrate (4) on which optical fibers and the like are laid is placed. In order to lay an optical fiber or the like on the substrate (4) at a desired position, there are a type in which the wiring head is driven and a type in which the stage is driven.

Using such a fiber wiring device, a step of laying an optical fiber (2) and a step of laying a heating wire (3) are performed. Each of the steps may be first, or the steps may be performed simultaneously.

For example, when the heating wire (3) is laid first, the heating wire (3) supplied from the bobbin of the fiber wiring device is sent out from the fiber delivery port of the wiring head. The stage moves the substrate (4) so that the sent heating wire (3) is wound into a predetermined coil shape. The heating wire (3) sent out is fixed by an adhesive layer provided on the substrate (4). Next, the bobbin of the heating wire (3) is replaced with the bobbin of the optical fiber (2),
Alternatively, the optical fiber (2) is installed by switching to another fiber wiring device. The sent out optical fiber (2) is fixed by an adhesive layer on the substrate (4) like the heating wire (3).

As a method for fixing the optical fiber (2) and the heating wire (3) on the substrate (4), a method of providing an adhesive layer (10) on the substrate (4) or a direct film layer (5) Method of coating and fixing with, or substrate made of thermoplastic resin (4)
There is a method of fixing the optical fiber (2) etc. while melting with an ultrasonic welder.

[0042]

The present invention has the following effects.
That is, since the heating wire for heating the optical fiber is laid on the substrate together with the optical fiber, the temperature of the heating wire is directly transmitted to the optical fiber, and it is not necessary to separately form the temperature adjusting element. Therefore, the optical fiber sheet can be made extremely compact. Further, since the temperature sensor for controlling the temperature of the optical fiber and the fiber temperature adjusting circuit are also provided on the substrate, there is no need for a separate temperature detecting device, and the optical fiber sheet does not become large. Therefore, even when a large number of optical fiber sheets according to the present invention are combined to form a component, an effect is achieved that an extremely small space is required.

[Brief description of drawings]

FIG. 1 is a schematic plan view of an optical fiber sheet according to a first embodiment.

FIG. 2 is an end view of a main part of the optical fiber sheet shown in FIG.

FIG. 3 is a schematic diagram showing a positional relationship between an optical fiber and a heating wire.

FIG. 4 is a schematic plan view of an optical fiber sheet according to a second embodiment.

5 is an end view of the main part of the optical fiber sheet shown in FIG. 3, taken along the line bb '.

FIG. 6 is a diagram showing an algorithm of a fiber temperature adjusting circuit according to the present invention.

[Explanation of symbols]

(1) Optical fiber sheet (2) Optical fiber (3) Heating wire (4) Substrate (5) Film layer (6) Temperature sensor (7) Fiber temperature control circuit (8) Current-carrying electrode (9) Wiring (10) Adhesive layer (11) Thermal insulation layer

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Claims (6)

[Claims] 1. An optical fiber sheet comprising an optical fiber and an electric heating wire for heating the optical fiber provided on a substrate. 2. The optical fiber sheet according to claim 1, wherein a temperature sensor for detecting the temperature of the optical fiber is provided on the substrate. 3. The optical fiber sheet according to claim 1, further comprising a fiber temperature adjusting circuit on the substrate, the fiber temperature adjusting circuit controlling an amount of electricity supplied to the heating wire so that the optical fiber has a predetermined temperature. An optical fiber sheet characterized by being provided. 4. The optical fiber sheet according to claim 1, wherein an energizing electrode for energizing the heating wire is provided on the substrate. Optical fiber sheet. 5. The optical fiber sheet according to any one of claims 1 to 4, wherein the substrate is provided with a heat dissipation effect. 6. A method of manufacturing an optical fiber sheet, comprising the steps of laying an optical fiber on a substrate and laying a heating wire for heating the optical fiber on the substrate. .