JPH037917A - Optical separating and switching device for wavelength multiplex signal - Google Patents

Abstract

PURPOSE:To select wavelength without any deterioration in the intensity of signal light by amplifying or attenuating wavelength multiplex signal light in a rare earth element added optical fiber which is different in amplification degree. CONSTITUTION:An input optical fiber 1 is connected to the incident terminal of an optical branch device 2, whose two projection terminals are connected to one-incidence-terminal sides of optical couplers 5 and 6 through optical fibers 3 and 4 for connection. Then exciting light beams from Nd exciting light sources 15 and 16 are made incident on the other-incidence-terminal sides of the optical couplers 5 and 6 under the control of a control circuit 19. Then the exiting terminals of the optical couplers are connected to one-incidence-terminal sides of optical couplers 9 and 10 through Nd-added optical fibers 7 and 8. Further, exciting light beams from Bgamma exciting light sources 17 and 18 are made incident on the other-incidence-terminal sides of the optical couplers 9 and 10 under the control of the control circuit 19. Then the exiting terminals of the optical couplers 9 and 10 are connected to output optical fibers 13 and 14 through Bgamma-added optical fibers 11 and 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is applied to optical fiber communication in which signal transmission is performed by propagating a plurality of signal lights of different wavelengths in an optical fiber.

The present invention provides a wavelength multiplex signal light separation/switching device that separates a plurality of signal lights having different wavelengths propagating through a certain optical fiber and propagates each signal to a plurality of different optical fibers. By using fiber,
The wavelength is selected without deteriorating the intensity of the signal light.

[Conventional technology]

Wavelength multiplexing transmission is a transmission form in which a plurality of optical signals with different wavelengths are multiplexed and transmitted through a single optical fiber, and is characterized by the ability to effectively utilize the low loss properties of optical fibers over a wide wavelength range.

FIG. 10 shows a conventional device for separating transmitted wavelength-multiplexed signal light.

On the transmitting side, the signals from the signal sources 102 and 102 are output as signal light by light sources 103 and 104 having different wavelengths, respectively. These signal lights are sent to a multiplexer 105
The signal light is multiplexed by the optical fiber 106 and enters the optical fiber 106 as a wavelength-multiplexed signal light.

On the receiving side, the wavelength-multiplexed signal light propagated through the optical fiber 106 is split by a splitter 107, and then passed through the optical wavelength filter 1.
The wavelength is separated by 08.109. The wavelength-separated signal light is transmitted to a light receiving element 110 and a detection circuit 11, respectively.
2. The light is converted into an electrical signal by the light receiving element 111 and the detection circuit 113.

In the current technology, the transmission loss of the signal light by the multiplexer 105, the splitter 107, and the optical wavelength filters 108 and 109 is large, and it is necessary to amplify the signal light at the electrical signal stage and convert it back into an optical signal. That is, it is necessary to amplify each signal using signal amplifiers 114 and 115, and propagate the signals from light sources 116 and 117 to optical fibers 11g and 119, respectively.

In addition, it is difficult to alternately transmit signal lights of different wavelengths with a single optical wavelength filter. Must be grounded.

[Problem to be solved by the invention]

As described above, in the conventional technology, the intensity of the signal light in the separation device is significantly degraded, and it is difficult to alternately transmit signal lights of different wavelengths with one optical wavelength filter. Therefore, when wavelength-multiplexed signal light is separated in the middle of a transmission path and sent to a receiving end further away, an opto-electrical circuit and an electro-optic conversion circuit are required to amplify the signal light, as well as multiple optical filters and their respective components. It is necessary to arrange a drive circuit, which has the disadvantage of complicating the configuration. Furthermore, for the same reason, it is necessary to use a large number of wavelength optical filters and their driving circuits in order to arbitrarily switch the propagation paths of separated signal lights of different wavelengths.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a wavelength-multiplexed signal light separation/switching device capable of separating wavelength-multiplexed signal light and switching the transmission path of the separated signal light with a simple configuration. .

[Means to solve the problem]

The wavelength-multiplexed signal optical separation/switching device of the present invention provides a wavelength-multiplexed signal comprising branching means for branching wavelength-multiplexed signal light, and wavelength selection means for transmitting light of a specific wavelength for each of the branched signal lights. In the optical separation/switching device, the wavelength selection means includes a plurality of rare-earth element-doped optical fibers having different wavelength characteristics of optical amplification, and means for individually controlling the excitation state of the plurality of rare-earth element-doped optical fibers. It is characterized by

The wavelength selection means may include an optical fiber doped with a plurality of rare earth elements having different wavelength characteristics of optical amplification, and means for individually controlling the excitation state of the rare earth elements contained in the optical fiber.

[For production]

Signal light is excited into an optical fiber doped with a rare earth element at a wavelength at which the amplification of the rare earth element or one rare earth element is maximized. Thereby, only the signal light having a wavelength corresponding to the excited rare earth element can be amplified, and the wavelength-multiplexed light can be separated into signal light having each wavelength.

In addition, when optical fibers doped with different rare earth elements are connected in cascade to control the excitation state of each, or when optical fibers doped with multiple rare earth elements are used, excitation to excite the rare earth elements can be used. By simply controlling the operating state of the light source, the wavelength transmitted through each path can be controlled. This makes it possible to switch transmission paths for signal lights with different wavelengths.

〔Example〕

FIG. 1 is a block diagram of a wavelength multiplexed signal optical separation/switching device according to a first embodiment of the present invention.

This device includes an optical splitter 2 as branching means for branching wavelength-multiplexed signal lights, and further includes wavelength selection means for transmitting light of a specific wavelength for each of the branched signal lights.

Here, the feature of this embodiment is that the wavelength selection means includes an Nd-doped optical fiber 7.8 and an Er-doped optical fiber 11.12 as a plurality of rare earth element-doped optical fibers having different wavelength characteristics of optical amplification. , Nd-doped optical fiber 7
．． Optical coupler 5.6.9.10S as means for individually controlling the excited states of 8 and Er-doped optical fibers 11.12.
Nd excitation light sources 15, 16, E' excitation light sources 17, 18 and control circuit 19 are provided.

A human powered optical fiber 1 is connected to the input end of the optical splitter 2,
The two output ends of the optical splitter 2 are connected to connecting optical fibers 3.4.
are connected to one input end of the optical coupler 5.6, respectively. Excitation light from Nd excitation light sources 15.16 enters the other input end of the optical coupler 5.6 under the control of the control circuit 19, respectively.

The output ends of the optical couplers 5.6 are each connected via an Ndff1 optical coupling fiber 7.8 to one input end of the optical coupler 9.10. At the other input ends of the optical couplers 9 and 10, Er excitation light sources 17 .
Excitation light from 18 enters. The output ends of the optical couplers 9.10 are connected to output optical fibers 13.14 via E'-doped optical fibers 11.12, respectively.

Figure 2 shows an example of the amplification characteristics of the Nd-doped optical fiber.
FIG. 3 shows an example of loss characteristics of a Nd-doped optical fiber.

The Nd-doped optical fiber is a silica-based optical fiber or a fluoride-based optical fiber with neodymium Nd added to the core.

The characteristics shown in Figure 2 are as follows: The amount of neodymium added is 11,000p.
This was obtained when excitation light with a wavelength of 0.514-m was input with a power of about 690 mW into an Nd-doped fluoride optical fiber with a fiber length of 0.5 m. Further, the characteristics shown in FIG. 3 were obtained when the same Nd-doped fluoride optical fiber was used without excitation light. These properties are described in the book "Amplification φ and Lasing at 1350 nm in a Neodymium Element Doped Fluorozirconite" by Brierley and Miller.
Electronics Letters, Vol. 24, No. 7, pp. 438-439, 1988 (M, C0
Br1erley, C.A., MiiJar, “Am
plification and lasing at
135Qnm in neodymium do
ped flioro zilconate fibr
e.

Snake1ec, Lett,, Vol, 24. No7
．． Imp, 438-439 (198g))
This is what was shown in .

The intensity of the signal light before being amplified is approximately several μW to several hundred μW. The degree of amplification varies depending on the amount of neodymium added, the length of the Nd-doped optical fiber, and the power of pumping light. Further, the wavelength at which the amplification is maximum varies mainly depending on the wavelength of the excitation light and the raw material of the optical fiber to which it is doped.

Also, when neodymium element is added to silica-based optical fiber,
Added neodymium is 0.5, 0.8 or 0.9 μm
Excited by light of a nearby wavelength, 0.9.1.06.1.3
Amplify the signal light near 5JLrB. For more information on this, see, for example, Ball Urquhart's Review of
“Rare Earth Doped Fiber Lasers and Amplifiers”, Proceedings of IC.
EEE, Vol. 135 Pt, J No. 6, pp. 385-407, 1988 (Paul Urquhar
t.

”Review of rare earth dop
ed fiber 1asers andampl i
f 1ers”, Proc, Iεεε, Vol,
135. Pt, J, No, 6゜pp, 38
5-407 (1988)).

Figure 4 shows an example of the amplification characteristics of the Er-doped optical fiber.
FIG. 5 shows an example of loss characteristics of an Er-doped optical fiber.

The characteristics shown in Figure 4 are based on the Technical Guidance of the 1989 Optical Fiber Communications Conference held in Houston, Texas, USA, paper number PD15, Hagimoto et al.
km/Non-revved transmission experiment at/1, 8Gb/s/Using
LD Panbutton Br3+ Doped Fiber Amplifiers in an IM/Direct-Detection Repeater System" (Hagimoto
, et a11'^ 212km non-rep
eatentransm+ss+onexprer
+ment at 1.8Gb/s usingL
D pumped Er”-doped fiber
r ampl+fire in anIM/Direc
t-Detection repeater system
em, Optical Fiber Communi
cation conference 19g9 Te
chnicalDigest (Houston, Te
xas), 1989. PD15).

In addition, the characteristics shown in Figure 5 are based on "Efficient Br 3 +" Doped Optical Fiber Amblifier Panbuto Pi.
"A 1.48μ, m InGaAsP laser diode", Applied Physics Letters, Vol. 54, No. 4, 1989, pp. 295-297 (M.

Nakazawa, Y., Kimura and K.
5uzuki, “Efficientεr”-dop
ed optical fiber amplifier
r pumped by 1.4hm InGaA
sP 1aser diode", Appl, P
hys.

Lett, Vol. 54. No, 4. pp, 2
95-297 (1989)).

Er-doped optical fibers are quartz-based optical fibers or fluoride-based optical fibers with erbium added to the core. When erbium element is added to a silica-based optical fiber, the added erbium is excited by light having a wavelength of around 0.8, 1.0 or 1.5 μm,
Amplify the signal light near m.

The characteristics shown in Figure 4 are the same when the amount of erbium added is 30pp.
m, an Er-doped optical fiber with a fiber length of about 90 m,
This was obtained when excitation light with a wavelength of 1.48μ0 was incident with a power of approximately 80+nW. The amplification degree varies depending on the amount of erbium added, the length of the Er-doped optical fiber, and the power of the pumping light. Further, the wavelength at which the amplification is maximum varies depending mainly on the wavelength of the excitation light, the raw material of the optical fiber to which it is added, and the length of the optical fiber. In order to amplify the signal light most efficiently, the amount of erbium added is approximately 11,000 pp.

Conditions of an optical fiber length of 2 to 3 ms, a pumping light power of about 50 mW, and a pumping wavelength of 1.48 μm are often used.

Next, the operation of the embodiment shown in FIG. 1 will be explained.

In the initial state, the control circuit 19 controls the Nd excitation light source 15 and the E
The r excitation light source 1B is brought into operation, and the Nd excitation light source 16 and Br excitation light source 17 are put into a non-operation state. At this time, the wavelength-multiplexed signal light propagating through the input optical fiber 1 is divided into equal parts by the optical splitter 2, half of the signal light enters the connection optical fiber 3, and the other half of the signal light enters the connection optical fiber 3. It enters the fiber 4. Here, the wavelength multiplexed signal light has a wavelength λ
, =1.35μ0 signal light and wavelength λ, =1.53
5 μm signal light.

The signal light branched to the connection optical fiber 3 is sent to the optical coupler 5
The light enters the Nd-doped optical fiber 7 via the Nd-doped optical fiber 7. here,
Since the Nd excitation light source 15 is in operation, excitation light is generated from it and excites the Nd-doped optical fiber 7 via the optical coupler 5. At this time, the signal of wavelength λ1 included in the wavelength multiplexed signal light is transferred to the Nd-doped optical fiber 7 in the excited state.
It is amplified as it propagates inside. On the other hand, the wavelength λ2
The intensity of the signal light decreases due to loss in the Nd-doped optical fiber 7.

The signal light of wavelength λ1 amplified by the Nd-doped optical fiber 7 and the attenuated signal light of wavelength λ2 enter the Er-doped optical fiber 11 via the optical coupler 9. E: If the pumping light source 17 is in the operating state, the Eri optical fiber II will be in the pumping state, and the signal light with the wavelength λ2 will be amplified. However, here, since the Br pumping light source 17 is in the non-operating state, , λ2 are not amplified, and E
Loss occurs within the r-doped optical fiber 11.

In this way, the signal light with wavelength λ1 is amplified within the Nd-doped optical fiber 7, but the signal light with wavelength λ2 suffers a large loss and is attenuated. At this time, the amplification degree of the Nd-doped optical fiber 7 is adjusted, and the optical branching device 2, the connecting optical fiber 3, the optical coupler 5.9, the Nd-doped optical fiber 7 and the Er
By performing amplification so that the loss of the signal light of wavelength λ1 caused by the doped optical fiber II is compensated for, the wavelength λ,
Only the signal light is transferred from the human-powered optical fiber 1 to the output optical fiber 1.
3.

Since the Nd excitation light source 16 is in an inactive state, the signal light branched to the connection optical fiber 4 is attenuated at both wavelengths λ1 and λ2 within the Nd-doped optical fiber 8. Furthermore, since the fEr excitation light source 18 is in operation, the signal light with the wavelength λ is attenuated in the Br-doped optical fiber 12, and only the signal light with the wavelength λ2 is amplified. Therefore, the amplification degree of the Er-doped optical fiber 12 is adjusted, and the wavelength λ generated by the optical splitter 2, the connecting optical fiber 4, the original coupling fiber 6.10, the Nd-doped optical fiber 8, and the Er-doped optical fiber 12 is adjusted.
By amplifying to compensate for the loss of 2, the wavelength λ
Only 2 signals are transferred from input optical fiber 1 to output optical fiber 1.
4.

Further, the control circuit 19 sets the Nd excitation light source 15 and the Er excitation light source 18 to a stopped state, and the Nd excitation light source 16 and
When the εr excitation light #17 is set to the operating state, the signal light with the wavelength λ1 is transmitted from the input optical fiber L to the output optical fiber 14, and the signal light with the wavelength λ2 is transmitted from the human-powered optical fiber 1 to the output optical fiber 13. .

In this way, from the control circuit 19 to the Nd excitation light sources 15 and 16,
By controlling the operating state of the excitation light source at high speed, the signal lights of wavelength λ and wavelength λ2 can be instantly separated and selected, and can be transmitted to separate output optical fibers 13 and 14, respectively.

Also, between the Nd-doped optical fiber 7 and the optical coupler 9, between the Nd-doped optical fiber 8 and the optical coupler 100, between the Er-doped optical fiber 11 and the output optical fiber 13, and between the Br-doped optical fiber 12 and the output optical fiber 14. It is desirable to arrange an optical wavelength filter between the two, which transmits the signal light and blocks the excitation light. As a result, the Nd-doped optical fiber 7.8
Alternatively, it is possible to separate the excitation light and signal light propagating through the doped optical fibers 11 and 12, allowing only the signal light to propagate, thereby making it possible to propagate the signal light with less noise.

FIG. 6 is a block diagram of a wavelength multiplexed signal optical separation/switching device according to a second embodiment of the present invention.

In this embodiment, instead of using an Nd-doped optical fiber and an Er-doped optical fiber separately, they are combined into a Nd-doped optical fiber and an Er-doped optical fiber is used.
This embodiment differs greatly from the first embodiment in that a DFR codoped optical fiber is used. Furthermore, accompanying this, Nd excitation light and Ei
This embodiment differs from the first embodiment in that the r excitation light is input to the Nd-11ir codoped optical fiber via a common optical coupler.

That is, the feature of this embodiment is that the wavelength selection means includes an Nd-8r co-doped optical fiber 2L 22 as an optical fiber doped with a plurality of rare earth elements having different wavelength characteristics of optical amplification. The optical coupler 5. is used as a means for individually controlling the excited state of the rare earth element contained in the
6.23.24, a Nd excitation light source 15.16, an Er excitation light source 17.18, and a control circuit 19 are provided.

A human powered optical fiber 1 is connected to the input end of the optical splitter 2,
The two output ends of the optical splitter 2 are each coupled to one input end of the optical coupler 5.6 via a connecting optical fiber 3.4. A Nd excitation light source 15 and an Er excitation light source 17 are connected to the other input end of the optical coupler 5 via an optical coupler 23, and an Nd excitation light source 15 and an Er excitation light source 17 are connected to the other input end of the optical coupler 6 via an optical coupler 24. The Nd excitation light source 16 right and the Er excitation light source 18 are connected. The output ends of the optical couplers 5 and 6 are each Nd-E.
It is connected to output optical fiber 13.14 via r-codoped optical fiber 2122.

The Nd-Br co-doped optical fiber 2122 is an optical fiber in which neodymium and erbium are added to the core of an optical fiber such as a silica-based optical fiber or a fluoride-based optical fiber.

FIG. 7 shows an example of the amplification characteristics of the Nd-Er co-doped optical fiber, and FIG. 8 shows an example of the loss characteristics. These characteristics are described in Kimte Nakazawa, “Multi-wavelength 0W laser oscillation in a Nd'° and εr 3 + double-doped fiber laser,” Applied Physics Letters, Vol. 53, No. 14, 1988, pp. 1251-1253 (Y, Kimura and M, Nakazawa,
”Multi-wavelength cw 1as
er oscillation in a Nd”an
dEr” double doped fiber
1aser, Appl, Phys.

t, eu,, Vol, 53. No, 14. pp,
1251-1253 (1988)).

Here, the characteristics shown in Figure 7 are that the amount of neodymium added is 1100
pp, x Nd-E with an added amount of rubylum of 900 ppm
This was obtained when excitation light with a wavelength of 0.514 μm was incident on the r-codoped optical fiber. Pumping light power is several meters
It is about W to several hundred mW. When the Er-doped optical fiber in the first embodiment of the Nd-Er co-doped optical fiber is pumped under the pumping conditions, that is, the pumping wavelength is 1.48 μm, the excitation power is about 50 m, only the erbium element is excited, and a signal with a wavelength of 1.535 μl is excited. The light is amplified and has a wavelength of 0.
When excited at 9 μm, only the neodymium element is excited, and signal light with a wavelength of 1.06 μm and 1.35 μm is amplified.

Next, the operation of the embodiment shown in FIG. 6 will be explained.

First, the Nd excitation light source 15 is put into operation state, and the Er excitation light source 17 is put into operation state.
When the operation is stopped, the excitation light generated by the Nd excitation light source 15 enters the Nd-Er co-doped optical fiber 21 via the optical coupler 23.5. This excitation light causes Nd-
The neodymium within the Er co-doped optical fiber 21 becomes excited. At this time, the wavelength λ1 λ branched by the optical splitter 2
When the signal light including λ2 enters the Nd-Er co-doped optical fiber 2I, only the signal light with the wavelength λ1 is amplified, and the signal light with the wavelength λ2 is amplified.
The signal light attenuates. Therefore, only the signal light having the wavelength λ1 is transmitted from the input optical fiber 1 to the output optical fiber 13.

In addition, the Nd excitation light source 15 is in a stopped state, and the Er excitation light #
17 is in the operating state, the pumping light generated by the Er pumping light source 17 pumps the erbium in the Nd-Er co-doped optical fiber 21, and only the signal of the wavelength signal λ1 can be amplified. That is, only the signal light having the wavelength λ2 can be transmitted from the manual optical fiber 1 to the output optical fiber 13.

Nd excitation light source 16, Er excitation light source 18, optical coupler 24.
6, and the Nd-Er co-doped optical fiber 22, the Nd excitation light source 16 and the 6r excitation light source 18
The wavelength of the signal light transmitted from the human-powered optical fiber 1 to the output optical fiber 14 can be controlled depending on the operating state.

In this way, by switching the excitation light incident on the Nd-Er co-doped optical fiber 2122, the signal light of wavelength λ1 and wavelength λ2 can be separated, and the signal light of each wavelength can be sent to separate output optical fibers 13. .14 can be transmitted.

FIG. 9 is a block diagram of a wavelength multiplexed signal optical separation/switching device according to a third embodiment of the present invention.

This embodiment differs from the first embodiment in that an Nd-doped optical fiber and an Er-doped optical fiber are arranged in parallel.

A human powered optical fiber 1 is connected to the input end of the optical splitter 2,
The two output ends of the optical splitter 2 are optical splitters 31.3, respectively.
It is connected to the input end of 2.

The two output ends of the optical splitter 31 are each connected to one input end of the optical coupler 5.9 via a connecting optical fiber 34.33. 1 at the other input end of the optical coupler 5.9.
, a Nd excitation light source 15 and an Er excitation light source 17 are connected, respectively. The output ends of the optical couplers 5.9 are respectively connected to the input ends of the optical couplers 370 via connecting optical fibers 7.11. The output optical fiber 13 is connected to the output end of the optical coupler 37.
is connected.

The two output ends of the optical splitter 32 are respectively connected to one input end of the optical coupler 6, IO via connecting optical fibers 35 and 36. At the other input end of the optical coupler 6.10, a Nd excitation light source 16 and an Er excitation light #! 18 are connected. The output ends of the optical couplers 6.10 are respectively connected to the input ends of the optical coupler 38 via connecting optical fibers 8.12. The output optical fiber 14 is connected to the output end of the optical coupler 38 .

In this embodiment, the Nd excitation light source 15 is in the operating state, and the E
When the excitation light source 17 is stopped, the signal light branched by the optical splitter 31 is transmitted to the Nd-doped optical fiber 7.
The wavelength λ1 component of the signal light incident on the Er-doped optical fiber 11 is amplified, and the signal light incident on the Er-doped optical fiber 11 is attenuated. When these signal lights are combined by the optical multiplexer 37, the amplified wavelength λ
Only one signal light is output to the output optical fiber 13. Furthermore, in the opposite operating state, a signal light having a wavelength λ2 is obtained at the output optical fiber 13.

The same applies to the output optical fiber 14 side.

〔Effect of the invention〕

As explained above, the wavelength-multiplexed signal optical separation/switching device of the present invention amplifies or attenuates the wavelength-multiplexed signal light in rare-earth element-doped optical fibers with different amplification degrees, so that only the signal light of the amplified wavelength is transmitted. can be transmitted to an output optical fiber. Further, by controlling the excitation state of the rare earth element-doped optical fiber, any signal light can be propagated to any output optical fiber, and the propagation path of the signal light can be switched.

INDUSTRIAL APPLICABILITY The present invention can separate and switch wavelength-multiplexed signal light without using a complicated electric circuit, and is particularly effective when used in optical wavelength-multiplexed communications.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a wavelength multiplexed signal optical separation/switching device according to a first embodiment of the present invention. FIG. 2 is a diagram showing an example of the amplification characteristics of the Nd-doped optical fiber. FIG. 3 is a diagram showing an example of loss characteristics of a Nd-doped optical fiber. FIG. 4 is a diagram showing an example of amplification characteristics of an Er-doped optical fiber. FIG. 5 is a diagram showing an example of loss characteristics of an Er-doped optical fiber. FIG. 6 is a block diagram of a wavelength multiplexed signal optical separation/switching device according to a second embodiment of the present invention. FIG. 7 is a diagram showing an example of the amplification characteristics of an optical fiber not doped with Nd-Er. FIG. 8 is a diagram showing an example of loss characteristics of an optical fiber without Nd-Er co-doping. FIG. 9 is a block diagram of a wavelength multiplexed signal optical separation/switching device according to a third embodiment of the present invention. FIG. 10 is a block diagram of a conventional device that separates transmitted wavelength-multiplexed signal light. 1... Human powered optical fiber, 2.31.32... Optical splitter, 3.4.33-36... Optical fiber for connection, 5.
6.9.10.23.24.37.38... Optical coupler, 7.8... Nd-doped optical fiber, 11.12...
εri optical fiber, 13.14... Output optical fiber, 15.16... Nd excitation light source, 17.18...B
r excitation light source, 19...control circuit, 2L 22...N
d/Er co-doped optical fiber 101.102...Signal source, 103.104.116.117...Light source, 10
5... Multiplexer, 106.118.119... Optical fiber, 107... Brancher, 10g, 109... Optical wavelength filter, 110.111... Light receiving element, 112
．． 113...Detection circuit, 114.115...Signal amplifier.

Claims (1)

[Claims] 1. A wavelength multiplexed signal light separation/switching device comprising branching means for branching wavelength-multiplexed signal light and wavelength selection means for transmitting light of a specific wavelength for each of the branched signal lights. , the wavelength selection means includes a plurality of rare-earth element-doped optical fibers having different wavelength characteristics of optical amplification, and means for individually controlling the excitation state of the plurality of rare-earth element-doped optical fibers. A wavelength multiplexing signal optical separation/switching device. 2. In a wavelength multiplexed signal light separation/switching device comprising a branching means for branching wavelength-multiplexed signal light and a wavelength selection means for transmitting light of a specific wavelength for each of the branched signal lights, the wavelength selection means is a wavelength multiplexing method comprising: an optical fiber doped with a plurality of rare earth elements having different wavelength characteristics of optical amplification; and means for individually controlling the excitation state of the rare earth elements contained in the optical fiber. Signal light separation and switching device.