JP2003202422A - Optical attenuation module, optical amplifier using the same, and exciting light source - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably attenuate high-output light when characteristics of a high- output type optical device, optical equipment, etc., are measured or an optical transmission system including an exciting light source and an optical amplifier is monitored and controlled. <P>SOLUTION: Between a connector 1a as a light input end and a connector 1b as a light output end, optical attenuators 3-1 to 3-n which are connected in series from the connector 1a to the connector 1b and increase in light attenuation quantity in order are provided and connected to one another by optical fibers 4-1 to 4-m. Light inputted from the connector 1a is attenuated by the optical attenuators 3-1 to 3-n one after another, and at this time, the optical attenuators 3-1 to 3-n have nearly the same light consuming power. <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 a high-power optical device for measuring the characteristics of a high-power optical device or optical equipment, or for monitoring and controlling an optical transmission system including a pumping light source and an optical amplifier. The present invention relates to an optical attenuating module capable of stably attenuating light and increasing the maximum light receiving level of a light receiving element, an optical amplifier and a pumping light source using the same.

[0002]

2. Description of the Related Art Recently, the development of optical communication equipment is remarkable,
An optical fiber amplifier and a laser diode for pumping to obtain a high output of 1 W have also been developed. When measuring the characteristics of such a high-power type optical device or optical device, for example, the optical output is measured by measuring the amount of heat of the light emitted from the optical device or optical device. However, in order to measure the wavelength characteristics, the gain, the noise figure, etc. of the optical device or the optical device, it is necessary to attenuate the optical output to a level permitted by the measuring instrument.

The maximum allowable input level of light in this type of measuring instrument is, for example, about 10 mW (10 dBm), and when the linearity of the measuring level of this measuring instrument is taken into consideration, it is 1 mW (0 dBm) to 0. 1 mW (-10 dBm)
It is preferable to use it within a range. Therefore, in order to measure the characteristics of the high output light of 1 W described above, 30 dB is required.
It is necessary to make a large attenuation.

[0004]

By the way, in the case of attenuating the light guided to the measuring instrument through the optical fiber, the attenuation of the light is caused by the optical attenuator in the middle of the optical transmission line formed by the optical fiber. It is performed by being inserted.
In this case, generally, an optical attenuator suitable for a desired attenuation is selected from a plurality of optical attenuators having various attenuation factors,
Light is attenuated by inserting the selected optical attenuator in the middle of the above-mentioned optical transmission path.

However, when an optical attenuator is selected by paying attention only to the amount of attenuation, when high-output light is input to the selected optical attenuator, the optical attenuator is overheated due to the heat generated by the attenuation of the optical output. There is a problem that a load is applied and the optical attenuator may be damaged. That is, the optical attenuator itself has a maximum allowable input level, and generally, the larger the attenuation amount, the smaller the maximum allowable input level. For this reason,
If a high output light is to be greatly attenuated by using one optical attenuator, the heat generated by the attenuating action of the optical output becomes excessive in this attenuator, and the heat generation causes damage to the optical attenuator. There was a problem that occurred.

On the other hand, monitoring the signal light amplified by the optical amplifier and the pumping light from the pumping light source used for the optical amplifier is an essential process for controlling the optical output, issuing an alarm, and monitoring the optical level. Is. Currently, optical amplifiers have been developed to a level at which 1 W signal light can be output. For example, in some Raman optical amplifiers, the output of pumping light output from a pumping light source exceeds 1 W. In order to monitor the signal light output from the optical amplifier and the pumping light used in the optical amplifier, the signal light and the pumping light are demultiplexed by an optical multiplexer / demultiplexer, and the demultiplexed optical output is received by a light receiving element ( PD).

However, when monitoring high output light, there is a problem that the PD may not operate correctly due to saturation of the light receiving level of the PD. There is also a problem in that the PD may be damaged if the received light level far exceeds the allowable received light level. Further, there is a problem that oscillation or the like may occur inside the optical circuit due to the reflected light of the PD. When such a problem occurs, there is a problem that an accurate monitor cannot be realized and the function of the optical amplifier is finally lowered.

In order to solve the above-mentioned problems of the prior art, the present invention measures the characteristics of a high-power type optical device or optical equipment, or monitors an optical transmission system including a pumping light source and an optical amplifier, An object of the present invention is to provide an optical attenuating module capable of stably attenuating high-output light when controlling and increasing the maximum light receiving level of a light receiving element, an optical amplifier and a pumping light source using the same. And

[0009]

[Means for Solving the Problems]
In order to achieve the object, the optical attenuation module according to claim 1 is an optical attenuation module which gives predetermined attenuation to light input from an optical input end and outputs the attenuated light from an optical output end, wherein the optical input end is provided. To a plurality of optical attenuators are connected toward the optical output end, each optical attenuator has an optical attenuation rate set respectively, the optical attenuation rate of each optical attenuator,
It is characterized in that each optical attenuator is set to a value at which it is not damaged by the optical power consumption input to each.

In the optical attenuating module according to a second aspect of the present invention, the optical attenuators are connected in series from the optical input end to the optical output end, and the optical attenuating rate of each optical attenuator sequentially increases. It is characterized by being set to a value.

The optical attenuating module according to a third aspect is an optical attenuating module which gives a predetermined attenuation to the light input from the optical input end and outputs the attenuated light from the optical output end. An optical attenuator in which the optical attenuation rate per unit length sequentially increases toward the light output end is provided.

Further, in the optical attenuation module according to claim 4, in the above invention, the optical consumption power consumed by each optical attenuator or the optical consumption power consumed by the optical attenuator per unit length is substantially the same. It is set to.

An optical attenuating module according to a fifth aspect of the present invention has a pair of optical input / output terminals, and gives a predetermined attenuation to the light input from one optical input / output terminal, and outputs the attenuated light to the other optical input / output terminal. In an optical attenuating module that outputs from an input / output terminal, a plurality of optical attenuators connected in series between the pair of optical input / output terminals are provided, and an optical attenuator connected in the vicinity of the one optical input / output terminal is It is characterized in that the optical attenuation factor is set to be relatively lower than that of other optical attenuators connected in series.

An optical attenuating module according to a sixth aspect of the present invention has a pair of optical input / output terminals, and imparts a predetermined attenuation to the light input from one optical input / output terminal, and applies the attenuated light to the other optical input / output terminal. In the optical attenuation module for outputting from the input / output end, the optical attenuation rate per unit length is sequentially increased from the one optical input / output end side to the vicinity of the center between the pair of optical input / output ends, and from the vicinity of the center, It is characterized in that an optical attenuator in which the optical attenuation rate per unit length is successively reduced to the other optical input / output end side is provided.

According to a seventh aspect of the present invention, in the above-mentioned invention, the optical attenuating module consumes the bidirectional light consumed by each optical attenuator with respect to the bidirectional light input / output between the pair of optical input / output terminals. The light consumption power or the light consumption power consumed by the optical attenuator per unit length is set to be substantially the same.

Further, in the optical attenuating module according to an eighth aspect of the present invention, in the above invention, the optical attenuating rate of the plurality of optical attenuators or the optical attenuating rate per unit length of the optical attenuator is equal to that of the pair of optical attenuators. It is characterized in that the input and output terminals are set substantially symmetrically.

According to a ninth aspect of the present invention, in the above-mentioned invention, the plurality of optical attenuators or the optical attenuator have a light absorbing material in one or both of a core portion and a clad portion of an optical fiber. It is characterized in that it is an added optical attenuation fiber.

According to a tenth aspect of the present invention, in the above-mentioned invention, the light absorbing material is cobalt (Co), chromium (Cr), copper (Cu), zinc (Z).
n), lead (Pb), iron (Fu), aluminum (A
l), nickel (Ni), manganese (Mn), and vanadium (V), which is an organometallic compound containing one or more kinds of transition metal ions.

According to an eleventh aspect of the present invention, in the above-mentioned invention, the light attenuating module is characterized in that the light absorbing material is a rare earth element.

According to the twelfth aspect of the present invention, in the above-mentioned invention, the light-attenuating fiber has the same kind of the absorbing material added thereto, and the light-attenuating rate depends on the length of the light-attenuating fiber. It is characterized by being set.

According to a thirteenth aspect of the present invention, in the above-mentioned invention, the light attenuating fiber is the same kind of absorbing material added, and the amount of the absorbing material added to the light attenuating fiber is different. The optical attenuation factor is set.

According to a fourteenth aspect of the present invention, in the above invention, the optical attenuating module is used as a terminator for eliminating light reflection.

According to a fifteenth aspect of the present invention, in the above-mentioned invention, the optical attenuating module is characterized in that the plurality of attenuators or the attenuators are housed in a heat dissipation case.

According to a sixteenth aspect of the present invention, in the above-mentioned invention, the optical attenuation module is characterized in that the heat dissipation case is provided with an air cooling unit having fins for air cooling.

Further, the optical attenuation module according to a seventeenth aspect is characterized in that, in the above invention, the heat dissipation case is provided with a liquid cooling unit using a heat pipe.

According to an eighteenth aspect of the present invention, in the above-mentioned invention, the optical attenuation module is characterized in that the heat dissipation case is provided with an air cooling unit having a fan for air cooling.

According to a nineteenth aspect of the present invention, in the above-mentioned invention, the light attenuation module is characterized in that the heat dissipation case is provided with a ventilation hole for air cooling.

An optical amplifier according to claim 20 has an excitation light source, an amplification optical fiber, and a control circuit, and also has an optical demultiplexer for optical monitoring and a light receiving element for optical monitoring. In the above, an optical attenuator is provided between the optical demultiplexer and the light receiving element.

According to a twenty-first aspect of the present invention, in the above invention, the optical attenuator is the optical attenuating module according to any one of the first to nineteenth aspects.

According to a twenty-second aspect of the present invention, in the above invention, the optical attenuator is one or more optical multiplexers / demultiplexers.

An optical amplifier according to a twenty-third aspect is the optical amplifier according to the above-mentioned invention, wherein one of the one or more optical multiplexers / demultiplexers.
One optical multiplexer / demultiplexer is a wavelength optical multiplexer / demultiplexer including a PLC coupler.

According to a twenty-fourth aspect of the present invention, in the above invention, the branch port of the optical multiplexer / demultiplexer is a termination port, and the termination port is connected to the optical attenuation module. To do.

An excitation light source according to a twenty-fifth aspect is an excitation light source having a light source and a control circuit, and an optical demultiplexer for optical monitoring and a light receiving element for optical monitoring. And an optical attenuator provided between the light receiving element and the light receiving element.

According to a twenty-sixth aspect of the present invention, in the above-mentioned invention, the excitation light source is characterized in that the optical attenuator is the optical attenuation module according to any one of the first to nineteenth aspects.

A thirty-seventh aspect of the present invention is the excitation light source according to the above invention, wherein the optical attenuator is one or more optical multiplexers / demultiplexers.

A pumping light source according to a twenty-eighth aspect of the present invention is one of the one or more optical multiplexers / demultiplexers according to the above invention.
One optical multiplexer / demultiplexer is a wavelength optical multiplexer / demultiplexer including a PLC coupler.

According to a twenty-ninth aspect of the present invention, in the above invention, the branch port of the optical multiplexer / demultiplexer is a termination port, and the termination port is connected to the optical attenuation module. To do.

According to a thirtieth aspect of the present invention, in the above invention, at least the light source, the light receiving element, and the optical attenuator are housed in a heat dissipation case.

According to a thirty-first aspect of the present invention, in the above invention, the light source, the light receiving element, and the optical attenuator are connected to a heat sink inside the heat dissipation case.

According to a thirty-second aspect of the present invention, in the above-mentioned invention, the excitation light source is characterized in that the heat dissipation case is provided with an air cooling unit having fins for air cooling.

The excitation light source according to a thirty-third aspect of the present invention is characterized in that, in the above invention, the heat dissipation case is provided with a liquid cooling unit using a heat pipe.

According to a thirty-fourth aspect of the present invention, in the above-mentioned invention, the excitation light source is characterized in that the heat dissipation case is provided with an air cooling unit having a fan for air cooling.

[0043]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical attenuation module according to the present invention, an optical amplifier using the same, and a pumping light source will be described below with reference to the accompanying drawings.

(Embodiment 1) First, Embodiment 1 of the present invention will be described. 1 is a partially cutaway plan view showing a schematic configuration of an optical attenuation module according to a first embodiment of the present invention. In FIG. 1, the optical fiber with connector 1 having the connector 1a forms a light input end, and the optical fiber with connector 2 having the connector 2a forms a light output end. As shown in FIG. 2, the n attenuators 3-1 to 3-n are sequentially connected in series and are inserted between the optical fibers 1 and 2 with a connector. The optical attenuators 3-1 to 3-n are connected by m (m = n-1) optical fibers 4-1 to 4-m. That is, each optical fiber 1, 4-1
˜4-m, 2 are respectively connected to both ends of each optical attenuator 3-1 to 3-m, and each optical attenuator 3-1 to 3-n is connected in series. Each of the optical attenuators 3-1 to 3-n includes a pair of dimming plates tilted in opposite directions between a pair of collimator lenses that form a light input / output unit to attenuate light.

The optical attenuators 3-1 to 3-n perform loss fusion by shifting the axes of the optical fibers 1, 4-1 to 4-m, 2 in order, that is, the optical fibers. The axis offset loss fusion structure may be formed to attenuate the light.
In this case, each optical attenuator 3-1 to 3-n can simplify the structure of the entire optical attenuating module by adopting such an axial displacement loss fusion bonding structure.

Here, the optical attenuators 3-1 to 3-n are mounted side by side on a V-groove chip 5 having a plurality of V-grooves formed in parallel, as shown in FIG. And is housed in a box-shaped heat dissipation case 7. V groove tip 5
The holding plate 6 transfers the heat generated by the optical output attenuating action of each of the optical attenuators 3-1 to 3-n to the heat radiating case 7 so that the optical attenuators 3-1 to 3-n are thermally activated. And it keeps mechanically stable. The heat dissipation case 7 radiates the heat generated in the optical attenuators 3-1 to 3-n to the outside as described later, and removes the thermal load of the optical attenuators 3-1 to 3-n. The heat dissipation case 7 also has a function of blocking light leaking from the optical attenuators 3-1 to 3-n.

Here, the optical attenuators 3-1 connected in series are connected.
The attenuation amounts of 3 to 3-n are sequentially increased from the side of the optical fiber with connector 1 functioning as an optical input end toward the side of the optical fiber with connector 2 functioning as an optical output end. Then, the optical power consumed in each of the optical attenuators 3-1 to 3-n is made substantially the same, the heat generated from each of the optical attenuators 3-1 to 3-n is averaged, and the heat load is dispersed. Is going.

For example, the optical attenuators 3-1 to 3-n have 20
When the number is one, when the optical attenuator numbers “1” to “20” are associated with the respective optical attenuators 3-1 to 3-20, as shown in FIG. 4, they are connected to the optical fiber 1 with a connector. The optical attenuator 3-1 (optical attenuator number “1”) is set to the minimum optical attenuation amount, and the optical attenuator 3-20 (optical attenuator number “20”) connected to the optical fiber 2 with a connector is set. The optical attenuator number "1" with the maximum optical attenuation set and connected in series
The "20" optical attenuator is set so as to obtain a desired attenuation amount. And the optical fiber with connector 1
A high-power type optical device or optical device (not shown) is connected to the connector 1a, and a measuring device (not shown) is connected to the connector-attached optical fiber 2.

Here, the optical attenuation amounts of the optical attenuators 3-1 to 3-20 are set to be gradually larger toward the optical output end side,
The optical input input to each of the optical attenuators 3-1 to 3-20 gradually decreases toward the optical output end side. As a result, as shown in FIG. 5, the optical power consumption (mW) consumed by each optical attenuator 3-1 to 3-20 is substantially the same as that of each optical attenuator 3-1 to 3-20. be able to. As a result, the heat load on each of the optical attenuators 3-1 to 3-20 becomes substantially the same, the amount of heat generated from each of the optical attenuators 3-1 to 3-20 becomes substantially the same, and the heat load dispersion is achieved. It As a result,
The thermal design of the optical attenuator module is facilitated, and thermal destruction of the optical attenuators 3-1 to 3-20 is prevented. Further, each of the optical attenuators 3-1 to 3-20 can lower the maximum allowable input level of the received light as compared with one optical attenuator configuration, so that the cost of manufacturing the optical attenuating module can be reduced. Can be reduced.

In FIG. 5, each optical attenuator 3-1 to 3-3-
Although the optical power consumption of the optical attenuator 20 is set to be approximately the same, the present invention is not limited to this, and in the thermal design of the optical attenuator module, a part of the optical attenuators 3-1 to 3-20 corresponding to a place having a good heat radiation property is provided. The light attenuation amount may be set so as to increase the light consumption power. Further, when the optical attenuators 3-1 to 3-n are arranged in parallel, the heat dissipation characteristics of the central portion deteriorate, so the optical power consumption of the optical attenuator arranged in the central portion is arranged in the peripheral portion. It may be set to be smaller than the optical power consumption of the optical attenuator that has been set.

Further, in the first embodiment described above, the optical attenuators are formed by being connected in series, but the present invention is not limited to this, and a series of optical attenuators connected in series may be connected in parallel. Good. Thereby, the power consumption of light can be further dispersed.

Further, in the above-described first embodiment, each optical attenuator is configured to continuously change the optical attenuation amount, but the present invention is not limited to this, and two or three optical attenuators having the same optical attenuation amount are used. The optical attenuation amount may be changed stepwise for each optical attenuator. In this case, an optical attenuator having the same amount of optical attenuation can be used, so that the configuration can be simplified and the cost can be reduced.

(Second Embodiment) Next, a second embodiment of the present invention will be described. In the first embodiment described above, the light input to each of the optical attenuators 3-1 to 3-n is unidirectional, but in the second embodiment, the light is bidirectionally input / output. Intended for damping modules.

The optical attenuating module according to the second embodiment has the same structure as that of the first embodiment, but both the connectors 1a and 2a of the optical fibers 1 and 2 with connectors function as optical input / output terminals. . That is, the light is transmitted from the connector 1a to the connector 2a, and the light is also transmitted from the connector 2a to the connector 1a, and the light is attenuated in each direction.

In the second embodiment, each optical attenuator 3-1 is used.
As shown in FIG. 6, the optical attenuation amounts of 3 to 3-20 are obtained from the optical attenuators 3-10 and 3-11 (optical attenuator numbers “10” and “11”) provided in the middle. Optical attenuators 3-1 and 3-20 (optical attenuator numbers "1" and "2" provided on the output end side
0)) side is set in order. That is, the respective attenuation amounts of the optical attenuators 3-1 to 3-10 connected in series are
The optical attenuators 3-1.3-20 at both ends of the optical attenuator 3-10 and 3-11 are set in stages so that the optical attenuators 3-1.3-20 are the smallest and the optical attenuators 3-10 and 3-11 located in the middle are the largest. The fibers 1 and 2 are set so as to form a symmetrical shape and sequentially change.

Specifically, when the specification is given to attenuate light (eg, laser light) having a wavelength of 1550 nm and an output of 1 W to 1 mW, the total attenuation amount in the optical attenuation module is 3.
It is set as 0 dB. When the number of the plurality of optical attenuators 3-1 to 3-n incorporated in this optical attenuating module is 20, the optical attenuator 3-on the optical fiber with connector 1 side 3-
A total of 9 optical attenuators 3-1 to 1 to 3 to 9
The light is attenuated by 10 dB in 3-9, the light is attenuated by 10 dB in the two optical attenuators 3-10 and 3-11 positioned in the middle, and further, from the optical attenuator 3-12 to the optical attenuator 3-20. Nine optical attenuators 3-12 to 3-20
Each optical attenuator 3 to attenuate the light by 10 dB at
The attenuation amount of 1 to 20 is set.

In particular, the attenuation amounts of the optical attenuators 3-1 to 3-n are
The optical attenuators 3-1 to 3-3 are formed in a mountain-shaped symmetrical shape between the pair of optical fibers 1 and 2 with a connector and are changed stepwise.
The total of 9 optical attenuators up to 9 are used to sequentially output 1 W of light 10 times.
Assuming that each of the optical attenuators 3-1 to 3-20 connected in series is attenuated by 0 mW, the attenuation amount of each of the optical attenuators 3-1 to 3-20 shown in FIG.
Is set as shown in FIG.
A graph of the light consumption power of 0 is shown in FIG.

That is, the attenuation amounts of the plurality of optical attenuators 3-1 to 3-20 connected in series are the optical attenuators 3-1 and 3-20 (optical attenuator number) on the side of the pair of optical input / output terminals. "1", "2"
0 ") and the optical attenuator sequentially positioned from the central side is increased stepwise. Specifically, the optical attenuators 3-1, 3-2
0 to optical attenuators 3-10 and 3-11, respectively, [0.46 dB], [0.51 dB], [0.58 dB], ~
Set each as [5.00 dB]. And 1
Regardless of which side of the pair of light input / output ends, the light of W is input, the nine optical attenuators on the input side 3-
1 to 9 or the optical attenuators 3 to 20 to 3 to 100 mW each, and the total attenuation is 10 dB.

The optical power consumption of each attenuator 3-1 to 3-10 in bidirectional light input / output will now be described. The optical power consumption L1 for the optical input from the optical fiber with connector 1 to the optical fiber 2 with connector and the optical power consumption L2 for the optical input from the optical fiber with connector 2 to the optical fiber 1 with connector are added. Attenuator 3-
The optical power consumption of 1 to 3-20 is as shown in FIG. The added optical power consumption is added to each attenuator 3-1 to 3-3.
Each is about 100 mW with respect to −20, whereby the heat load is dispersed and thermal destruction is prevented. In this case, since there is no directionality of light transmission, connection errors with respect to the light source, the measuring instrument, etc. do not occur, and the handling thereof becomes easy.

(Third Embodiment) Next, a third embodiment of the present invention will be described. Embodiments 1 and 2 described above
In the above, each of the optical attenuators 3-1 to 3-n attenuates the light due to the axis shift of the light shielding plate or the optical fiber, but in the third embodiment, each of the attenuators 3-1 to 3-n. This structure is formed by an optical attenuating fiber to which a light absorbing material such as an organometallic compound containing a transition metal ion or a rare earth element is added.

The optical attenuating fiber includes cobalt (Co), chromium (Cr), copper (Cu), zinc (Zn) and lead (P).
b), iron (Fu), aluminum (Al), nickel (Ni), manganese (Mn) and vanadium (V), an organometallic compound containing one or more kinds of transition metal ions, or samarium (Sm), thulium. (Tm),
When a rare earth element such as praseodymium (Pr) is used as a dopant and added to one or both of the core portion 9a and the cladding portion 9b of the optical fiber, light in a predetermined wavelength range is absorbed, and thereby the light is attenuated. The organometallic compounds include CoO, NiO, CoCl ₂ , C
o (NO ₃ ) ₂ etc. In addition, the rare earth element includes all rare earth elements.

As shown in FIG. 10, a light-attenuating fiber, for example, a light-attenuating fiber 3-1 is provided with an optical connector T1 at both ends of a fiber having a core portion 9a doped with a light absorbing material.
It is connected at T2 and housed in the casing 8. In the optical attenuating fiber 3-1, the optical fiber 1 is connected to the optical connector T1 side and the optical fiber 4-1 is connected to the optical connector T2 side.

Here, in the light-attenuating fiber, when the kind of the light absorbing material to be doped is the same and the doping amount is the same, the light attenuation amount can be set by the length of the fiber. Therefore, as shown in FIG. 10, the absorber to be doped is, for example, cobalt, and the lengths of the optical attenuating fibers having the same doping amount DP0 are sequentially lengthened to thereby increase the length of the optical attenuators 3-1 to 3-3. The amount of light attenuation can be increased sequentially. For example, the optical attenuators 3-1 to 3-3 have lengths L, 2L, and 3L, respectively, and the optical attenuation amount of the optical attenuator 3-1 is 1 dB.
In this case, the optical attenuation amounts of the optical attenuators 3-2 and 3-3 are 2 dB and 3 dB, respectively. Therefore, in each of the optical attenuators 3-1 to 3-n illustrated in FIG. 4, the lengths of the optical attenuating fibers are appropriately set to be long and connected in series, so that each of the optical attenuators illustrated in the first embodiment can be obtained. The light attenuation amount of the attenuators 3-1 to 3-n can be easily set. Similarly, the length of each optical attenuating fiber is set to be long from both ends, and the attenuators 3 shown in the second embodiment are connected in series.
The light attenuation amounts of -1 to 3-n can be easily set.

Alternatively, the light absorbing material doped in the light attenuating fiber may be the same, and the light absorbing amount may be set by changing the doping amount of the light absorbing material. This is because when the light absorbing materials are of the same type, the increase / decrease in the light attenuation amount corresponds to the increase / decrease in the doping amount. For example, as shown in FIG.
All the optical attenuating fibers have the same length L, and each optical attenuator 3
-1 to 3-3 Doped Amount of Metal Doped DP1 to D
By sequentially increasing P3, each optical attenuator 3-1
It is possible to sequentially increase the light attenuation amount of 3-3. For example, with respect to the doping amount DP1 of the light absorbing material doped in the optical attenuator 3-1, the doping amounts DP2 and DP3 of the light absorbing material doped in the optical attenuators 3-2 and 3-3 are 2 respectively.
If it is set to double or triple, the light attenuation amount can be set to double or triple. Of course, the relationship between the doping amount and the optical attenuation amount is determined by the function between them. In this case, all the optical attenuators 3-1 to 3-n have the same length L.
Therefore, it is possible to realize a compact optical attenuation module.

Further, the above-described optical attenuating fiber may be formed continuously so that each of the optical attenuators 3-1 to 3-n is realized as one optical attenuator 3. That is, FIG.
As shown in, the doping amount DP1 toward the optical input direction AL
The doping amount is continuously increased to 1 to DP12. In this case, the optical power consumption per unit of the optical attenuator 3 which is an optical attenuating fiber can be made substantially the same, the heat load is dispersed, and the thermal destruction is prevented. Further, the optical fibers 4-1 to 4-m are connected between the optical attenuators 3-1 to 3-n.
Since it is not necessary to connect the optical attenuation module, the optical attenuation module can be easily manufactured.

Although the optical attenuator 3 shown in FIG. 12 is a single optical attenuator, this optical attenuator 3 is replaced by each optical attenuator 3.
It may be applied to -1 to 3-n. That is,
The heat load per unit length of each optical attenuator 3-1 to 3-n itself may be dispersed.

Further, in the light-attenuating fiber, since the light absorbing material is doped in the core portion or the clad portion of the optical fiber, light reflection is small, and the light-attenuating module shown in the above-described first to third embodiments is used as an optical fiber. It can be used as a terminator. Of course, the same applies to the optical attenuators 3-1 to 3-n configured to attenuate the light by shifting the axis of the light shielding plate or the optical fiber.

By the way, when constructing the optical attenuating module having the structure shown in the above-described first to third embodiments, for example, an inert gas is enclosed in the heat radiating case 7, and a plurality of optical attenuators 3-1 to 3-3- It is preferable to increase the heat transfer efficiency from n to the heat dissipation case 7. Then, as shown in FIG. 13, the entire heat dissipation case 7 is used as a heat radiation surface, or as shown in FIG. 14, heat dissipation fins 11 are attached to the heat dissipation case 7,
It is also preferable that the heat radiation effect is enhanced.
Further, it is also effective to incorporate a heat pipe 12 into the heat dissipation case 7 as shown in FIG. 15 to improve heat dissipation efficiency, or to incorporate an air-cooling fan 13 into the heat dissipation case 7 as shown in FIG. Further, the Peltier element may be used to forcibly cool the optical attenuator 3. In addition, when the heat dissipation case 7 is not filled with an inert gas, the case shown in FIG.
It is also useful to provide the ventilation case 14 in the heat dissipation case 7 as shown in FIG. 1 to enhance the air cooling effect of the optical attenuators 3-1 to 3-n housed in the heat dissipation case 7. However, in this case, it is necessary to take a light shielding measure so that light does not leak to the outside of the heat dissipation case 7 through the ventilation hole 14.

Further, a holding plate 6 which holds and holds the plurality of optical attenuators 3-1 to 3-n arranged on the V-groove chip 5.
Instead of the above, it is also useful to use the heat dissipation plate 15 as a pressing member thereof as shown in FIG. Alternatively, as shown in FIG. 19, a heat conductive sheet 16 such as a silicone sheet is interposed between the holding plate 6 and the optical attenuators 3-1 to 3-n, whereby the optical attenuators 3-1 to 3- Press plate 6 from n
It is also useful to increase the heat transfer efficiency of the and the cooling efficiency thereof.

Further, a plurality of optical attenuators 3-1 to 3-n connected in series and arranged on the V-groove chip 5 are arranged inward from both ends of the V-groove chip 5 as shown in FIG. It is desirable to arrange them alternately in order toward each other so that the distribution of heat generation from the respective optical attenuators 3-1 to 3-n on the V-groove chip 5 is not biased. For example, when the 20 optical attenuators 3 are arranged in a line on the V-groove chip 5 as described above, the optical attenuators 3 are arranged according to the numerical order [1], [19], [3],
[17], ~, [11], [10], ~, [4], [18], [2], [20]
The plurality of optical attenuators 3 on one side, which are divided with the central portion as a boundary, are arranged in the V-groove chip 5 respectively.
It may be arranged so as to be distributed over the entire width of. In addition, it is desirable to take various measures to efficiently cool the plurality of optical attenuators 3-1 to 3-n.

The present invention is not limited to the above embodiment. For example, the number of optical attenuators 3-1 to 3-n used in series connection and the attenuation amount of each attenuator 3-1 to 3-n may be determined according to the specifications. Further, the optical attenuators 3-1 to 3-n are not limited to the examples described above, and it is also possible to use an optical fiber in which an attenuation film excellent in durability and heat resistance is embedded. Also,
It is of course possible to use a plurality of types of optical attenuators of different types in combination. In particular, a plurality of optical attenuators 3-1 to 3-
Regarding the pattern of the change of the attenuation amount set stepwise with respect to n, for example, the thermal loads in the plurality of optical attenuators 3-1 to 3-n on one side divided with the central portion as a boundary are substantially equal. Thus, it is possible to determine the amount of attenuation.
In addition, the present invention can be variously modified and implemented without departing from the scope of the invention.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, an optical amplifier to which the optical attenuation module according to the first to third embodiments described above is applied will be described. FIG. 20 is a block diagram showing the configuration of an optical amplifier that is Embodiment 4 of the present invention to which the optical attenuation module shown in Embodiments 1 to 3 is applied. The optical amplifier shown in FIG. 20 is an example of an optical amplifier (EDFA) unit using an erbium-doped fiber. This optical amplifier includes an input connector 22 for inputting signal light, a first isolator 23 for blocking return light of the optical signal input to the input connector 22, and an erbium-doped fiber (ED) for amplifying the input optical signal.
F) 25, an LD unit 32 for exciting the EDF 25, an optical multiplexer / demultiplexer (WDM) 24 and an optical multiplexer / demultiplexer (WDM) 26 for multiplexing the excitation light of the LD unit 32 input to the EDF 25. , A second isolator 27 connected to the optical multiplexer / demultiplexer 26, and a second isolator 27.
An optical multiplexer / demultiplexer (coupler) 28 for branching the signal light to the output side and the monitor side, an optical output connector 29 for outputting the optical signal output from the coupler 28, and a coupler 2.
A light receiving element (PD) 31 for monitoring the level of the signal light branched at 8, an optical attenuation module (ATT) 30 connected between the PD 31 and the coupler 28, and a PD 31.
It has a control circuit 33 for controlling the LD unit 32 according to the light level received by the.

In the LD unit 32, a plurality of semiconductor laser elements (LD) that output laser light having a wavelength corresponding to the wavelength of the signal light and an optical multiplexer that multiplexes laser light having different wavelengths output from the plurality of LDs. It is composed of a duplexer. In addition,
The LD unit 32 may include a single LD and a demultiplexer that demultiplexes the laser light output from the LD. As the light attenuation module 30, the light attenuation module described in the first to third embodiments is applied. The optical multiplexer / demultiplexer 24 and the optical multiplexer / demultiplexer 26 have, for example, 1.48 μ.
The one that multiplexes the excitation light of the wavelength of m and the signal light of the wavelength of 1550 nm is used.

In FIG. 20, the signal light input to the input connector 22, for example, the signal light having a wavelength of 1550 nm is
It is input to the EDF 25 via the first isolator 23 and the optical multiplexer / demultiplexer 24. On the other hand, the pumping light having a wavelength of 1.48 μm output from the LD unit 32 enters the EDF 25 via the optical multiplexer / demultiplexer 24 and the optical multiplexer / demultiplexer 26, and excites the erbium atom in the EDF 25. At this time, if signal light with a wavelength of 1550 nm is input to the EDF 25, stimulated emission occurs and the signal light with a wavelength of 1550 nm is optically amplified. The amplified signal light having a wavelength of 1550 nm is output from the output connector 29 via the optical multiplexer / demultiplexer 26, the second isolator 27, and the coupler 28.

The EDFA shown in FIG. 20 has a maximum of 25 dB when the input signal wavelength is 1550 nm and the input signal output is 0 dBm.
m is the type that is output. The coupler 28 has a branch port attenuation of 18 dBm. Further, the optical attenuation module 30 uses optical fibers that are fused by axial misalignment so that the optical attenuation amount is 5 dB, but any of the optical attenuation modules described in the first to third embodiments described above is used. May be used. As a result of the experiment, PD31 had a maximum light receiving level of 5 dBm. Without the optical attenuation module 30, the maximum level of light input to the PD 31 is 7 dBm.
Therefore, the maximum light receiving level of the PD 31 is exceeded. In this case, the original optical output cannot be monitored, and the PD
31 may be damaged. In order to prevent this, the optical attenuation module 30 is connected between the coupler 28 and the PD 31. In this case, the maximum level input to PD31 is 2d.
It becomes Bm and can be kept within the maximum light receiving level of the PD 31. Moreover, since the optical attenuation module shown in the above-described first to third embodiments is used, the heat load is dispersed, and the thermal damage is further prevented.

The optical attenuator module 30 is not limited to the optical attenuator modules shown in the first to third embodiments, but a plurality of optical attenuators 3-1 to 3-n are not used and only one optical attenuator is used. The optical attenuation module used may be used. This is because, in this case, by providing the light attenuating module 30, there is an effect that the maximum light receiving level of the PD 31 can be increased.

When a plurality of optical attenuators 3-1 to 3-n are connected in cascade, the optical attenuation amount of each optical attenuator 3-1 to 3-n is as shown in the first to third embodiments. In Although,
Each light attenuation amount may be constant as shown in FIG. 21 (a), or as shown in FIGS. 21 (b) and 21 (c) and the first and third embodiments, the light may be input from the light input side. The light attenuation amount may be gradually increased toward the output side. In this case, the light attenuation amount may be continuously increased as shown in FIG. 21 (b), or may be increased stepwise as shown in FIG. 21 (c). In addition, as shown in FIG. 21D and the second embodiment, the optical attenuation amount of the cascaded optical attenuators arranged in the middle is maximized, and the optical attenuation of both ends of the cascaded optical attenuators is maximized. The optical attenuation amount may be set to be gradually decreased toward the container.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described. Although the output light of the EDFA is monitored in the fourth embodiment described above,
In the fifth embodiment, the optical attenuation module is applied when it is necessary to monitor the input light of the EDFA and the input light of high output is input.

FIG. 22 is a block diagram showing a part of the configuration of the optical amplifier according to the fifth embodiment of the present invention to which the optical attenuation module is applied. In FIG. 22, the optical multiplexer / demultiplexer 3 is provided between the input connector 22 and the first isolator 23.
8 is provided, an optical attenuation module 40 is provided between the optical multiplexer / demultiplexer 38 and the PD 41, and the optical level detected by the PD 41 is output to the control circuit 33. The optical attenuation module 40 is the optical attenuation module 30 described in the fourth embodiment.
It has the same structure as. Further, the other configurations are the same as those in the fourth embodiment.

In the fifth embodiment, in order to monitor the high-power input light, it is necessary to raise the maximum allowable light-receiving level of the PD 41. However, since the light-attenuating module 40 is used to further attenuate the input light, It is possible to raise the light receiving level of the PD 41. Further, as in the fourth embodiment,
Since the light attenuation module 40 is used, the heat load is dispersed and the heat damage can be prevented.

(Sixth Embodiment) Next, a sixth embodiment of the present invention will be described. In the above-described fourth embodiment, the optical attenuating module 30 is used to attenuate and monitor the branched output light, but in the sixth embodiment, an optical multiplexer / demultiplexer is used to attenuate the output light. I have to.

FIG. 23 is a block diagram showing a part of the configuration of the optical amplifier according to the sixth embodiment of the present invention. FIG. 23
In, the output light branched from the optical multiplexer / demultiplexer (coupler) 28 is input to the optical multiplexer / demultiplexer (coupler) 50, and a part of the output light P
While being output to D31, a part of the other output light is output to the optical terminator 51 and subjected to antireflection processing. Here, the optical terminator 51 may use the optical attenuating module described in the first to third embodiments. Further, it may be connected to another monitor port without being terminated by the optical terminator 51. The rest of the configuration is the same as that of the fourth embodiment.

As shown in FIG. 24, PDs 31-1 to 31-n for a plurality of wavelengths λ1 to λn are used instead of PD31.
Are provided in parallel, and the optical multiplexer / demultiplexer 50 and PDs 31-1 to 31-31
You may make it provide the wavelength optical multiplexer / demultiplexer 52 between n and n. By monitoring the output of each wavelength lambda ₁ to [lambda] _n, it is possible to control the output of the excitation light source corresponding to each wavelength lambda ₁ to [lambda] _n in the LD unit 32, resulting in a gain adjustment of the optical amplifier It can be performed.

Here, the wavelength optical multiplexer / demultiplexer 52 is specifically a PLC (Planar Lightwave: Planar Lightwave) shown in FIG.
Circuit) is realized by a coupler. FIG. 25 shows PL
It is a top view of a C coupler, and this PLC coupler has several Mach-Zehnder Interferomete (Mach-Zehnder Interferomete).
In FIG. 25, seven Mach-Zehnder interferometers are used for demultiplexing into _eight wavelengths (λ _{1 to} λ ₈ ).

The configuration of the coupler 50 and the optical terminator 51 described above may be combined in multiple stages as shown in FIG. That is, in FIG. 26, the coupler 50
-1 to 50-n are sequentially connected in a multi-stage, and each coupler 50-1
˜50-n branch ports to optical terminators 51-1 to 51-n
Connect each. The optical terminator 51 is connected to the branch port.
Instead of connecting -1 to 51-n, it may be connected to another monitor port. In addition, each coupler 50-1 to 50-
The branching ratio of n may be different. The light attenuation amount due to this branching ratio may have various attenuation distributions shown in FIG.

In the sixth embodiment, when the output light is monitored, it is attenuated by the coupler 50 and output to the PD 31, so that the light receiving level of the PD 31 can be increased and the optical terminator 51 is used in the first embodiment. Since the optical attenuating modules shown in 3 to 3 are used, the optical terminator 51
The heat load is dispersed, and it is possible to prevent thermal destruction.

In the fourth to sixth embodiments described above, the input signal light or the amplified signal light is monitored, but the present invention is not limited to this. For example, the amplified signal light is output from the output destination. The reflected light reflected may be branched by an optical multiplexer / demultiplexer, and the branched reflected light may be attenuated using the above-described optical attenuation module and monitored.

(Seventh Embodiment) Next, a seventh embodiment of the present invention will be described. Embodiment 7 of the present invention
Are pumping light sources to which the optical attenuation modules shown in the first to third embodiments are applied, as in the fourth to sixth embodiments.

FIG. 27 is a block diagram showing the structure of the excitation light source according to the seventh embodiment of the present invention. In FIG. 27, the optical pump unit 60A that is the excitation light source is
The D unit 60, the isolator 61 for preventing the return light due to the reflection of light, and the optical multiplexer / demultiplexer (coupler) 62 for branching the output light of the optical pump unit 60A into the output side and the monitor side.
An output connector 63 for outputting the excitation light, a PD 64 for monitoring the optical output, an optical attenuation module 65 connected between the coupler 62 and the PD 64, and an LD unit according to the optical level received by the PD 64. A control circuit 66 for controlling 60 is provided, and desired excitation light is output from the output connector 63. As shown in FIG. 28, this pumping light is output from the output connector 63 to the signal light transmission path via a coupler.

The LD unit 60 multiplexes a plurality of semiconductor laser elements (LDs) that output a laser beam having a wavelength corresponding to the wavelength of the signal light to be amplified and a laser beam having a different wavelength that is output from the plurality of LDs. It is composed of an optical multiplexer / demultiplexer. A single LD and a demultiplexer that demultiplexes the laser light output from the LD may be provided.

Here, the optical pump unit 60A is a type of pumping light source that outputs a maximum of 30 dBm. The branch port attenuation of the coupler 62 is 18 dB. In addition, the optical attenuation module 65 has an optical attenuation of 10d.
The optical fiber is used in which the optical fibers are axially fused so as to become B. As a result of the experiment, PD64 had a maximum received light level of 5 dBm. Without the optical attenuation module 65,
The maximum level of light input to the PD 64 is 12 dBm, which exceeds the maximum light receiving level of the PD 64. In this case, the original optical output cannot be monitored, and the PD64
May be damaged. In order to prevent this, the optical attenuation module 65 is inserted between the coupler 62 and the PD 64. In this case, the maximum level input to PD64 is 2d
Bm, which was within the maximum light receiving level of PD64.

Here, as shown in FIG. 29, instead of PD 64, PDs 64-1 to 64-- for each of a plurality of wavelengths λ1 to λn.
n in parallel, the optical attenuation module 65 and PD 64-1
25 to 64-n may be provided with the PLC coupler 67 shown in FIG. By monitoring the output for each wavelength λ _{1 to} λ _n , each wavelength λ in the LD unit 60 is monitored.
The output of the pumping light source corresponding to _{1 to} λ _n can be controlled, and as a result, the gain adjustment of the optical amplifier can be performed.

As in the optical amplifiers shown in the fourth to sixth embodiments, the optical attenuation module 65 may be replaced with an optical attenuation module having a multistage structure. Further, the attenuation distributions of the multi-stage optical attenuation modules as well as in the optical attenuation module may be various attenuation distributions as shown in FIG. Further, instead of the optical attenuation module 65, an optical multiplexer / demultiplexer (coupler) may be used for attenuation. Further, the coupler may have a multi-stage structure so as to have various attenuation distributions. Further, an optical terminator may be connected to the branch port of the coupler, and an optical attenuation module may be used as the optical terminator at this time.

The optical pump unit 60A is used for any of the forward pumping method, the backward pumping method, and the bidirectional pumping method. Further, it is also used in the optical amplifiers shown in the above-mentioned fourth to sixth embodiments. In this case, a Raman amplifier is shown, but the present invention is not limited to this, and is used in various optical fiber amplifiers such as EDFA.

Here, the above-described optical pump unit 60A is used.
Is modularized. FIG. 30 is an exploded view showing the arrangement of the optical pump unit. In FIG. 30,
LD units 60a to 60 corresponding to the LD unit 60
d and the light receiving element group p corresponding to the light receiving element 64 are the substrate 7
1 is placed on top. The optical attenuator group 65 corresponding to the optical attenuator module 65 and other components such as an isolator are arranged on the substrate 72. Although not shown in FIG. 30, optical fibers and control lines for connecting the respective parts are provided at necessary locations. The substrates 71 and 72 are
It is fitted into the housing 73, but at this time, in the housing 73, aluminum blocks 74 are provided at locations corresponding to the LD units 60a to 60d, the light receiving element group 64p, and the optical attenuator group 65.
a to 74d, 74 and 75 are provided respectively. That is, the aluminum block is provided at a position corresponding to the arrangement of the component that is the heat generation source, and promotes heat dissipation to the housing 73 and also has a function as a heat sink.

In FIG. 31, a heat sink 78 having fins is provided on the housing bottom surface 76 side of the optical amplifier unit 60A assembled as shown in FIG. 30 to provide a natural air cooling function. A lid 77 is provided on the upper surface of the casing 73, and an inert gas is sealed inside the casing 73. As a result, the heat radiation effect can be further enhanced, and the LD units 60a to 60d, the light receiving element group 64p, and the optical attenuator group 6 can be obtained.
It is possible to reduce the thermal load such as 5 and prevent thermal destruction.

Further, in FIG. 32, a plate-like Peltier element 81 and a plurality of fans 82a are used instead of the heat sink 78.
The cooling fan unit 82 having the components 82c to 82c is provided on the housing bottom surface 76 side. First, the Peltier element 81 is arranged on the bottom surface 76 of the housing, and the cooling fan unit 82 is further provided on the Peltier element 76. The Peltier element 81 controls the energization direction and the amount of current to the Peltier element 81 by a control circuit and a power source (not shown), and cools the casing 77. On the other hand, the cooling fan unit 82 forcibly radiates excess heat that cannot be cooled by the Peltier element 81.

Further, in FIG. 33, a heat pipe unit 91 is provided on the bottom surface 76 of the housing instead of the heat sink 78. The heat pipe unit 91 has a housing bottom surface 76.
The pipe 92 is arranged in a meandering manner so as to correspond to the surface, and heat is efficiently dissipated by using a refrigerant circulating in the pipe. In this case, a cooling fin as shown in FIG. 15 is attached to one end of the pipe 92 to radiate heat. A liquid cooling unit that simply causes the cooling water to flow may be used instead of the circulating refrigerant in the pipe 92.

In the seventh embodiment, since the PD receives the monitor light after the monitor light is attenuated by providing the optical attenuation module 65, the maximum light reception level of the PD is lowered and the maximum light reception level of the PD is decreased. In addition to the above, the optical attenuation module described in the first to third embodiments is used, so that the heat load is dispersed and the thermal destruction can be prevented.

[0100]

As described above, according to the present invention, the thermal load on the plurality of optical attenuators connected in series and the entire optical attenuating module is reduced, and high-power light is greatly attenuated. This has the effect of effectively preventing damage to the optical attenuator at that time.

Further, the optical attenuators of the plurality of optical attenuators are set so that the optical attenuators of the two ends of the optical attenuators are gradually increased, and the optical attenuator is set to be the largest in the vicinity of the center. Since it is set so as to be symmetric with respect to each other, it is possible to eliminate the directivity with respect to the propagation direction of light, and it is possible to greatly improve the handling property thereof. The power consumption can be made almost the same, the thermal load of the optical attenuator can be dispersed, and the damage of the optical attenuator can be prevented.

Further, since the attenuation amount of each optical attenuator is set by using the optical attenuation fiber, the precision is high and the fine optical attenuation amount can be set, so that the heat dispersion can be performed more effectively. Has the effect.

Further, since each optical attenuator is housed in a heat dissipation case and further cooled by an air cooling unit, a liquid cooling unit, etc., the optical attenuator is further prevented from being damaged and a highly reliable optical attenuating module is realized. There is an effect that can be done.

Further, according to the present invention, since the optical attenuation module is connected between the optical multiplexer / demultiplexer and the light receiving element, the maximum light receiving level of the light receiving element can be increased, and a high output optical amplifier and pumping light source are provided. There is an effect that it is possible to monitor the optical output level of.

Further, since the excitation light source is housed in the heat dissipation case and further cooled by the air cooling unit, the liquid cooling unit, etc., the heat sources such as the light source, the optical attenuator and the light receiving element are prevented from being damaged and the reliability is high. It is possible to realize an excitation light source.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration including a partial breakage of an optical attenuating module according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a connection state of optical attenuators in the optical attenuating module shown in FIG.

FIG. 3 is an assembly diagram showing an installed state of an optical attenuator in the optical attenuation module shown in FIG.

FIG. 4 is a diagram showing a relationship of an optical attenuation amount with respect to a connection order of optical attenuators.

FIG. 5 is a diagram showing a relationship of optical power consumption with respect to a connection order of optical attenuators.

FIG. 6 is a diagram showing the relationship of the optical attenuation amount with respect to the connection order of the optical attenuators of the optical attenuation module according to the second embodiment of the present invention.

FIG. 7 is a diagram showing the relationship between the optical output and the optical attenuation amount of each attenuator with respect to the connection order of the optical attenuators of the optical attenuating module according to the second embodiment of the present invention.

FIG. 8 is a diagram showing a relationship of optical power consumption in each optical input direction in each optical attenuator.

FIG. 9 is a diagram showing a relationship of combined optical power consumption for each optical input direction in each optical attenuator.

FIG. 10 is a diagram showing a connection state of a plurality of optical attenuators using optical attenuating fibers having the same amount of added light absorbing material.

FIG. 11 is a diagram showing a connection state of a plurality of optical attenuators using optical attenuating fibers having different amounts of added light absorbing materials.

FIG. 12 is a diagram showing an example of an optical attenuator using an optical attenuating fiber in which the amount of the light absorbing material added changes continuously.

FIG. 13 is a perspective view of the optical attenuating module showing a state where the optical attenuator is housed in a heat dissipation case.

FIG. 14 is a perspective view of the light attenuating module showing a state in which a heat dissipation fin is installed in a heat dissipation case.

FIG. 15 is a perspective view of the optical attenuation module showing a state where a liquid cooling unit using a heat pipe is installed in a heat dissipation case.

FIG. 16 is a perspective view of the optical attenuation module showing a state where an air cooling unit using an air cooling fan is installed in a heat dissipation case.

FIG. 17 is a perspective view of the light attenuating module showing a state in which ventilation holes are provided in the heat dissipation case.

FIG. 18 is a perspective view showing a heat dissipation plate attached to the V-groove chip.

FIG. 19 is a perspective view showing an installed state of a heat conductive sheet provided between a V-groove chip and a holding plate.

FIG. 20 is a block diagram showing a configuration of an optical amplifier according to a fourth embodiment of the present invention.

21 is a diagram showing an attenuation distribution of the optical attenuation module shown in FIG.

FIG. 22 is a block diagram showing a partial configuration of an optical amplifier according to a fifth embodiment of the present invention.

FIG. 23 is a block diagram showing a partial configuration of an optical amplifier according to a sixth embodiment of the present invention.

24 is a block diagram showing a modified example of a part of the configuration of the optical amplifier shown in FIG.

FIG. 25 is a plan view showing an example of a PLC coupler.

FIG. 26 is a diagram showing a multistage configuration of the optical multiplexer / demultiplexer shown in FIG. 23.

FIG. 27 is a block diagram showing a configuration of an excitation light source (optical pump unit) that is Embodiment 6 of the present invention.

28 is a diagram showing a state in which the optical pump unit shown in FIG. 27 is connected to an amplification fiber.

FIG. 29 is a block diagram showing a modification of the optical pump unit shown in FIG. 28.

30 is an assembly diagram showing an internal configuration of the optical pump unit shown in FIG. 27. FIG.

FIG. 31 is an assembly diagram showing a state where a heat sink is provided in the housing of the optical pump unit.

FIG. 32 is an assembly diagram showing a state in which a cooling fan unit is provided in the housing of the optical pump unit.

FIG. 33 is an assembly diagram showing a state where the heat pipe unit is provided in the housing of the optical pump unit.

[Explanation of symbols]

1, 2 Optical fiber with connector 1a, 2a Connector 3, 3-1 to 3-n Optical attenuator 4-1 to 4-m Optical fiber 5 V groove chip 6 Holding plate 7 Heat dissipation case 11 Heat dissipation fin 12 Heat pipe 13 Air cooling Fan 14 Vent 15 Heat sink 16 Heat conductive sheet 22 Input connector 23 First isolator 24, 26 Optical multiplexer / demultiplexer (WDM) 25 EDF 27 Second isolator 28, 50, 50-1 to 50-n, 62 Optical multiplexer / demultiplexer (coupler) 29 Optical output connector 30, 40, 65 Optical attenuator module 31, 31-1 to 31-n, 41, 64, 64-1 to 6
4-n, 64p light receiving element (PD) 32 LD unit 33, 66 control circuit 51, 51-1 to 51-n optical terminator 52, 67 wavelength multiplexer / demultiplexer (PLC coupler) 60, 60a to 60d LD unit 60A Optical pump unit 61 Isolator 63 Output connector 65 Optical attenuator group 71, 72 Substrate 73 Housing 74, 74a to 74d, 75, 78 Heat sink 76 Housing bottom 77 Lid 81 Peltier element 82 Cooling fan unit 82a to 82c Cooling fan 91 Heat Pipe unit 92 heat pipe

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H038 BA23 BA25                 5F072 AB09 AK06 HH02 JJ03 JJ09                       MM01 PP07 RR01 TT01 TT02                       TT03 TT04 TT11 TT12 TT15                       TT30 YY17                 5K102 AA53 MB02 MB09 MC11 MH12                       MH22 PH42

Claims (34)

[Claims] 1. An optical attenuating module for giving a predetermined attenuation to light input from an optical input end and outputting the attenuated light from an optical output end, wherein a plurality of light beams are provided from the optical input end toward the optical output end. An attenuator is connected, and each optical attenuator has its own set optical attenuator, and the optical attenuator of each optical attenuator is not damaged by the optical consumption power input to each attenuator. An optical attenuation module characterized by being set to a value. 2. The optical attenuators are connected in series from the optical input end toward the optical output end, and the optical attenuation factor of each optical attenuator is set to a value that increases sequentially. The optical attenuation module according to claim 1. 3. An optical attenuating module for giving a predetermined attenuation to light input from an optical input end and outputting the attenuated light from an optical output end, wherein a unit length is from the optical input end to the optical output end. An optical attenuating module comprising an optical attenuator in which the optical attenuating rate per hit increases in sequence. 4. The optical consumption power consumed by each optical attenuator or the optical consumption power consumed by the optical attenuator per unit length is set to be substantially the same. The optical attenuation module described in any one. 5. An optical attenuating module having a pair of optical input / output terminals, giving a predetermined attenuation to the light input from one optical input / output terminal, and outputting the attenuated light from the other optical input / output terminal. , A plurality of optical attenuators connected in series between the pair of optical input / output terminals, the optical attenuator connected in the vicinity of the one optical input / output terminal is connected to another optical attenuator connected in series. The optical attenuation module is characterized in that the optical attenuation rate is set to be relatively lower than that of the optical attenuation module. 6. An optical attenuating module having a pair of optical input / output terminals, giving a predetermined attenuation to light input from one optical input / output terminal, and outputting the attenuated light from the other optical input / output terminal. , The optical attenuation rate per unit length is sequentially increased from the one optical input / output end side to the vicinity of the center between the pair of optical input / output ends,
An optical attenuation module comprising an optical attenuator in which the optical attenuation rate per unit length is sequentially reduced from the vicinity of the center to the other optical input / output end side. 7. The bidirectional light consumption power consumed by each optical attenuator or the optical attenuator consumed per unit length for bidirectional light input / output between the pair of optical input / output terminals. The optical attenuating module according to claim 5 or 6, wherein the optical consumption powers to be set are set to be substantially the same. 8. The optical attenuation rate of the plurality of optical attenuators or the optical attenuation rate per unit length of the optical attenuators are set to be substantially symmetrical between the pair of optical input / output terminals. The optical attenuation module according to any one of claims 5 to 7. 9. The plurality of optical attenuators or the optical attenuators are optical attenuating fibers in which a light absorbing material is added to one or both of a core portion and a clad portion of an optical fiber. <8> The optical attenuation module according to any one of <8>. 10. The light absorbing material is cobalt (Co),
Chromium (Cr), Copper (Cu), Zinc (Zn), Lead (P
b), iron (Fu), aluminum (Al), nickel (Ni), manganese (Mn) and vanadium (V), which is an organometallic compound containing one or more kinds of transition metal ions. The optical attenuation module according to claim 9. 11. The light attenuation module according to claim 9, wherein the light absorbing material is a rare earth element. 12. The light-attenuating fiber has the same kind of absorbing material added thereto, and the light-attenuating rate is set by the length of the light-attenuating fiber.
<11> The optical attenuation module according to any one of <11> to <11>. 13. The light-attenuating fiber has the same kind of absorbing material added thereto, and the light-attenuating rate is set according to the amount of the absorbing material added to the light-attenuating fiber. <11> The optical attenuation module according to any one of <11> to <11>. 14. The optical attenuating module according to claim 1, wherein the optical attenuating module is used as a terminator for eliminating reflection of light. 15. The optical attenuation module according to claim 1, wherein the plurality of optical attenuators or the optical attenuators are housed in a heat dissipation case. 16. The optical attenuation module according to claim 15, wherein the heat dissipation case is provided with an air cooling unit having fins for air cooling. 17. The optical attenuation module according to claim 15, wherein the heat dissipation case is provided with a liquid cooling unit using a heat pipe. 18. The optical attenuation module according to claim 15, wherein the heat dissipation case is provided with an air cooling unit having a fan for air cooling. 19. The optical attenuation module according to claim 15, wherein the heat dissipation case is provided with a ventilation hole for air cooling. 20. An optical amplifier having an excitation light source, an amplification optical fiber, and a control circuit, and having an optical demultiplexer for optical monitoring and a light receiving element for optical monitoring, wherein the optical demultiplexer and the optical demultiplexer are provided. An optical amplifier characterized in that an optical attenuator is provided between the light receiving element and the light receiving element. 21. The optical amplifier according to claim 20, wherein the optical attenuator is the optical attenuation module according to any one of claims 1 to 19. 22. The optical amplifier according to claim 20, wherein the optical attenuator is one or more optical multiplexers / demultiplexers. 23. The optical amplifier according to claim 22, wherein one optical multiplexer / demultiplexer of the one or more optical multiplexers / demultiplexers is a wavelength optical multiplexer / demultiplexer including a PLC coupler. 24. The optical amplifier according to claim 22, wherein the branch port of the optical multiplexer / demultiplexer is a termination port, and the termination port is connected to the optical attenuation module. 25. An excitation light source having a light source and a control circuit, and having an optical demultiplexer for optical monitoring and a light receiving element for optical monitoring, wherein an optical source is provided between the optical demultiplexer and the light receiving element. An excitation light source having an attenuator. 26. The pump light source according to claim 25, wherein the optical attenuator is the optical attenuator module according to any one of claims 1 to 19. 27. The pumping light source according to claim 25, wherein the optical attenuator is one or more optical multiplexers / demultiplexers. 28. The pump light source according to claim 27, wherein one optical multiplexer / demultiplexer of the one or more optical multiplexers / demultiplexers is a wavelength optical multiplexer / demultiplexer including a PLC coupler. 29. The pumping light source according to claim 27, wherein the branching port of the optical multiplexer / demultiplexer is a termination port, and the termination port is connected to the optical attenuation module. 30. At least the light source, the light receiving element,
30. The pumping light source according to claim 25, wherein the optical attenuator is housed in a heat dissipation case. 31. The excitation light source according to claim 30, wherein the light source, the light receiving element, and the optical attenuator are connected to a heat sink inside the heat dissipation case. 32. The excitation light source according to claim 30, wherein the heat dissipation case is provided with an air cooling unit having fins for air cooling. 33. The excitation light source according to claim 30, wherein the heat dissipation case is provided with a liquid cooling unit using a heat pipe. 34. The excitation light source according to claim 30, wherein the heat dissipation case is provided with an air cooling unit having a fan for air cooling.