JP2714692B2 - Wavelength multiplexing signal light separation switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is used for optical fiber communication in which a plurality of signal lights having different wavelengths are propagated in an optical fiber to perform signal transmission.

The present invention relates to a wavelength division multiplexed signal light separation switching device for separating a plurality of signal lights having different wavelengths propagating in one optical fiber and for propagating each signal to a plurality of different optical fibers. By using the fiber, the wavelength is selected without deteriorating the intensity of the signal light.

[Conventional technology]

Wavelength multiplex transmission is a transmission form in which a plurality of optical signals having different wavelengths are multiplexed and transmitted via a single optical fiber, and is characterized in that the low loss property of the optical fiber over a wide wavelength range can be effectively used.

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

On the transmitting side, the signals from the signal sources 101 and 102 are output as signal lights by light sources 103 and 104 having different wavelengths. These signal lights are multiplexed by the multiplexer 105 and are incident on one optical fiber 106 as wavelength multiplexed signal light.

On the receiving side, the wavelength multiplexed signal light that has propagated through the optical fiber 106 is split by a splitter 107, and an optical wavelength filter 108,
The wavelength is separated by 109. The wavelength-separated signal light is
The light receiving element 110, the detection circuit 112, and the light receiving element 11,
The signal is converted into an electric signal by 1 and the detection circuit 113.

In the current technology, the signal light has a large transmission loss due to the multiplexer 105, the splitter 107, and the optical wavelength filters 108 and 109, and it is necessary to amplify at the stage of an electric signal and convert it to an optical signal again. That is, each signal is amplified by the signal amplifiers 114 and 115, and the optical fibers 11 are respectively transmitted from the light sources 116 and 117.
8, 119 must be propagated.

In addition, it is difficult for one optical wavelength filter to alternately transmit signal lights of different wavelengths. In order to transmit alternately, a plurality of optical wavelength filters are mechanically driven to transmit the signal light to the propagation path of the signal light. Must be grounded.

[Problems to be solved by the invention]

As described above, in the conventional technique, the signal light intensity is greatly degraded in the separation device, and it is difficult for one optical wavelength filter to transmit signal lights of different wavelengths alternately. For this reason, when the wavelength-division multiplexed signal light is separated in the middle of the transmission path and sent to a farther receiving end, an opto-electric circuit and an electro-optical conversion circuit for amplifying the signal light, a plurality of optical filters and It is necessary to arrange a drive circuit, and there is a disadvantage that the configuration is complicated. Further, 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 the separated signal lights having different wavelengths.

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

[Means for solving the problem]

A wavelength division multiplexed signal light separation and switching device according to the present invention is a wavelength division multiplexed signal comprising: a branching unit that branches a wavelength-multiplexed signal light; and a wavelength selection unit that transmits light of a specific wavelength for each of the branched signal lights. In the optical separation switching device, the wavelength selecting means includes a plurality of rare earth element-doped optical fibers having different wavelength characteristics of optical amplification, and means for individually controlling the excited state of the plurality of rare earth element-doped optical fibers. It is characterized by.

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

(Operation)

A signal light is excited in the optical fiber doped with the rare earth element at a wavelength at which the amplification degree of the rare earth element or one rare earth element is maximized. As a result, only the signal light having the wavelength corresponding to the excited rare earth element can be amplified, and the wavelength-division multiplexed light can be separated into signal lights of each wavelength.

In addition, the optical fibers doped with different rare earth elements are cascaded to control their respective excited states, or in the case of using an optical fiber doped with a plurality of rare earth elements, the excitation for exciting the rare earth elements is performed. Only by controlling the operation state of the light source, the transmission wavelength passing through each path can be controlled. This makes it possible to switch the transmission path of the signal light having a different wavelength.

〔Example〕

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

This device includes an optical splitter 2 as a splitting unit that splits a wavelength-multiplexed signal light, and further includes a wavelength selection unit that transmits light of a specific wavelength for each of the split signal lights.

Here, the feature of the present embodiment is that the wavelength selection means includes Nd-doped optical fibers 7 and 8 and Er-doped optical fibers 11 and 12 as a plurality of rare-earth element-doped optical fibers having different wavelength characteristics of optical amplification. , Nd-doped optical fibers 7 and 8 and Er-doped optical fibers 11 and 12 are individually controlled as optical couplers 5, 6, 9 and 10 and Nd pump light sources 15 and 1.
6. It has the Er excitation light sources 17, 18 and the control circuit 19.

The input optical fiber 1 is connected to the input end of the optical splitter 2, and the two output ends of the optical splitter 2 are connected to one of the input ends of the optical couplers 5 and 6 via connecting optical fibers 3 and 4, respectively. Connected to. Excitation lights from Nd excitation light sources 15 and 16 are incident on the other incident ends of the optical couplers 5 and 6, respectively, under the control of the control circuit 19. The output ends of the optical couplers 5 and 6 are connected to one incident end of the optical couplers 9 and 10 via Nd-doped optical fibers 7 and 8, respectively. Under the control of the control circuit 19, the other excitation ends of the optical couplers 9 and 10 are respectively provided with Er excitation light sources.
Excitation light from 17 and 18 is incident. The output ends of the optical couplers 9 and 10 are connected to output optical fibers 13 and 14 via Er-doped optical fibers 11 and 12, respectively.

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

The Nd-doped optical fiber is obtained by adding neodymium Nd to the core of a silica-based optical fiber or a fluoride-based optical fiber.

The characteristics shown in FIG. 2 are as follows.
A wavelength of 0.5 m is applied to a 0.5 m Nd-doped fluoride optical fiber.
This was obtained when 514 μm excitation light was incident at a power of about 690 mW. The characteristics shown in FIG.
This was obtained when an Nd-doped fluoride optical fiber was used without excitation light. These characteristics are described in "Amplification and Leasing at 1350 nm in a Neodmium Doped Fluorodil Conate Fiber", co-authored by Briarley and Miller, Electronics Letters, Vol. 24, No. 7, page 438. 439, 1988 (MCBrierley, CAMillar, “Amplification and lasi
ng at 1350nm in a neodymium doped flioro zilconate
fibre ", Elec. Lett., Vol. 24, No. 7, pp. 438-439 (198
8)).

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

When a neodymium element is added to a silica-based optical fiber, the added neodymium is excited by light having a wavelength of about 0.5, 0.8, or 0.9 μm, and amplifies signal light of about 0.9, 1.06, or 1.35 μm. For more information on this, see Paul
Arkhart, Review of Rare Earth Doped Fiber Lasers and Amplifiers, The Proceeding of IEEE, Vol. 135, Pt. J 6,
No. 385-407, 1988 (Paul Urquhart, “R
eview of rare earth doped fiber lasers and amplifi
ers ", Proc. IEEE, Vol. 135, Pt. J, No. 6, pp. 385-407 (198
8)).

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

The characteristics of Fig. 4 are shown in Technical Digest of Optical Fiber Communication Conference 1989 held in Houston, Texas, USA, Article No. PD15, Hagimoto et al., "A ・ 212km Non-repeatable Transmission Exchange.
At, 1.8Gb / s, Using, LD pumping, Er3 ⁺ doped fiber, amplifiers in an IM,
Direct Detection Repeater System ”(K. Hagimoto, et al.,“ A 212km non-repeated tra
nsmission expreriment at 1.8Gb / s using LD pump
ed Er ³⁺ −doped fiber amplifier in an IM / Direct−D
etection repeater system ", Optical Fiber Communicat
ion conference 1989 Technical Digest (Houston, Texa
s), 1989, PD15).

The characteristics in FIG. 5 are described in Nakazawa, Kimura and Suzuki, “Efficient Er ³⁺ Doped Optical
Fiber amplifier pump-by-a 1.
48 μm InGaAsP Laser Diode ”, Applied Physics Letters, Vol. 54, No. 4, 1989, pp. 295-297 (M. Nakazawa, Y. Kimura and K. Suzuki,“ Ef
ficient Er ³⁺ −doped optical fiber amplifier pumped
by a 1.48μm InGaAsP laser diode ", Appl.Phys.L
ett., Vol. 54, No. 4, pp. 295-297 (1989)).

The Er-doped optical fiber is obtained by adding an erbium element to the core of a silica-based optical fiber or a fluoride-based optical fiber. When erbium element is added to quartz optical fiber, the added erbium becomes 0.8, 1.0 or 1.5μm
It is excited by light having a nearby wavelength and amplifies signal light near 1.5 μm.

The characteristic shown in FIG. 4 is that the amount of erbium added is 30 pp.
m, an Er-doped optical fiber with a fiber length of about 90 m, a wavelength of 1.48
This was obtained when μm pump light was incident at a power of about 80 mW. The degree of amplification depends on the amount of erbium added, the length of the Er-doped optical fiber, and the power of the pump light.
The wavelength at which the degree of amplification is maximum is mainly the wavelength of the pump light,
It varies depending on the raw material of the optical fiber to be added and the length of the optical fiber. In this case, in order to efficiently amplify the signal light, the conditions where the amount of erbium added is about 1000 ppm, the optical fiber length is 2 to 3 m, the pumping light power is about 50 mW, and the pumping wavelength is 1.48 μm are often used.

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

As an initial state, the control circuit 19 sets the Nd excitation light source 15 and the Er excitation light source 18 into an operating state, and the Nd excitation light source 16 and the Er excitation light source 17
Are set to the operation stop state. At this time, the wavelength multiplexed signal light propagating through the input optical fiber 1 is equally divided by the optical splitter 2, half of the signal light enters the connecting optical fiber 3, and the other half of the signal light is connected to the connecting light. The light enters the fiber 4. Here, it is assumed that the wavelength multiplexed signal light includes a signal light having a wavelength λ ₁ = 1.35 μm and a signal light having a wavelength λ ₂ = 1.535 μm.

The signal light branched to the connection optical fiber 3 enters the Nd-doped optical fiber 7 via the optical coupler 5. here,
Since the Nd pumping light source 15 is in the operating state, pumping light is generated from this, and pumps the Nd-doped optical fiber 7 via the optical coupler 5. At this time, the wavelength λ ₁ included in the wavelength multiplexed signal light is
Is amplified while propagating through the Nd-doped optical fiber 7 in the excited state. On the other hand, the intensity of the signal light having the wavelength λ ₂ decreases due to the loss of the Nd-doped optical fiber 7.

The signal light of the wavelength lambda ₁ that has been amplified by the Nd-doped optical fiber 7, the attenuated wavelength lambda ₂ of the signal light via the optical coupler 9 is incident on the Er-doped optical fiber 11. If Er excitation light source 17 is the operating state, Er-doped optical fiber 11 is excited, the signal light of the wavelength lambda ₂ is amplified. But here
Since the Er excitation light source 17 is in an operation stop state, the wavelengths λ ₁ and λ
_No signal light of any of ₂ is amplified and Er-doped optical fiber
Loss within 11

Thus, the signal light of the wavelength lambda ₁ is being amplified in Nd-doped optical fiber 7, the signal light of the wavelength lambda ₂ is attenuates undergoing large losses. At this time, by adjusting the amplification degree of the Nd-doped optical fiber 7, an optical splitter 2, the connecting optical fiber 3, an optical coupler 5 and 9, the Nd-doped optical fiber 7 and the Er-doped optical fiber 11 resulting wavelength lambda ₁ of By performing amplification so as to compensate for the loss of the signal light, only the signal light having the wavelength λ ₁ is transmitted from the input optical fiber 1 to the output optical fiber 13.

Since the Nd pumping light source 16 is in an operation stop state, the signal light of the wavelengths λ ₁ and λ ₂ of the signal light branched to the connection optical fiber 4 is attenuated in the Nd-doped optical fiber 8. Also, Er
Since the excitation light source 18 is in the operating state, the Er-doped optical fiber 12
The inner, attenuated wavelength lambda ₁ of the signal light, only the signal light of the wavelength lambda ₂ is amplified. Therefore, the amplification degree of the Er-doped optical fiber 12 is adjusted, and the optical splitter 2, the connecting optical fiber 4, the optical couplers 6, 10, the Nd-doped optical fiber 8, and the wavelength λ ₂ generated by the Er-doped optical fiber 12 are adjusted. By amplifying to compensate for the loss, only the signal of wavelength λ ₂ is transmitted from input optical fiber 1 to output optical fiber 14.

The control circuit 19 controls the Nd excitation light source 15, the Er excitation light source 18
Is set to the operation stop state, and the Nd excitation light source 16 and the Er excitation light source 17
Is set to the operating state, the signal light having the wavelength λ ₁ is transmitted from the input optical fiber 1 to the output optical fiber 14, and the signal light having the wavelength λ ₂ is transmitted from the input optical fiber 1 to the output optical fiber 13.

Thus, the control circuit 19 sends the Nd excitation light sources 15, 16 and
By controlling the operating state of the Er pump light source at high speed, the signal lights of the wavelengths λ ₁ and λ ₂ can be instantaneously 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 10, between the Er-doped optical fiber 11 and the output optical fiber 13, and between the Er-doped optical fiber 12 and the output optical fiber. It is desirable to arrange an optical wavelength filter that transmits signal light and blocks excitation light during each of 14. As a result, the pump light and the signal light propagating through the Nd-doped optical fibers 7 and 8 or the Er-doped optical fibers 11 and 12 are separated,
Only signal light can be propagated, and signal light with less noise can be propagated.

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

In this embodiment, the Nd-doped optical fiber and the Er-doped optical fiber are not used separately,
The difference from the first embodiment is that an Er co-doped optical fiber is used. In addition to this, the second embodiment differs from the first embodiment in that Nd pumping light and Er pumping light are incident on an Nd / Er co-doped optical fiber via a common optical coupler.

That is, the feature of the present embodiment is that the wavelength selecting means is an Nd / Er co-doped optical fiber 2 as an optical fiber in which a plurality of rare earth elements having different wavelength characteristics of optical amplification degree are added.
The optical couplers 5 and 6 are provided as means for individually controlling the excited state of the rare earth element contained in the optical fiber.
23, 24, Nd excitation light sources 15, 16, Er excitation light sources 17, 18 and a control circuit 19.

An input optical fiber 1 is connected to the input end of the optical splitter 2, and two output ends of the optical splitter 2 are connected to one input end of the optical couplers 5 and 6 via the connecting optical fibers 3 and 4, respectively. Join. The Nd excitation light source 15 and the Er excitation light source 17 are connected to the other incident end of the optical coupler 5 via the optical coupler 23, and the other incident end of the optical coupler 6 is connected to the other incident end via the optical coupler 24. The Nd excitation light source 16 and the Er excitation light source 18 are connected. The output ends of the optical couplers 5 and 6 are respectively Nd / Er co-doped optical fibers 2
They are connected to output optical fibers 13 and 14 via 1 and 22.

The Nd / Er co-doped optical fibers 21 and 22 are optical fibers obtained by adding neodymium and erbium to the core of an optical fiber such as a silica-based optical fiber or a fluoride optical fiber.

FIG. 7 shows an example of the amplification characteristic of the Nd / Er co-doped optical fiber, and FIG. 8 shows an example of the loss characteristic. These characteristics are described by Kimura Nakazawa, “Multi-Wavelenks, cw Laser Oscillation in a Nd ³⁺ and Er.
³⁺ Doubly doped fiber laser, Applied Physics Letters, Vol. 53, No. 14, 1988.
Pages 1251 to 1253 (Y.Kimura and M. Nakazawa, “Mu
ltiwavelength cw laser oscilation in a Nd ³⁺ and Er
³⁺ doubly doped fiber laser ", Appl.Phys.Lett., Vol.5
3, No. 14, pp. 1251-1253 (1988)).

Here, the characteristics shown in FIG.
This was obtained when an excitation light having a wavelength of 0.514 μm was incident on an Nd / Er co-doped optical fiber having an addition amount of pm and erbium of 900 ppm. The pump light power is on the order of several mW to several hundred mW. The Nd-Er co-doped optical fiber was used as the pumping condition of the Er-doped optical fiber in the first embodiment, that is, the pumping wavelength was 1.48.
μm, when pumping with a pump power of about 50 mW, only the erbium element is pumped and the signal light with a wavelength of 1.535 μm is amplified,
When excited at a wavelength of 0.9 μm, only the neodymium element is excited, and signal lights having wavelengths of 1.06 μm and 1.35 μm are amplified.

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

First, when the Nd pump light source 15 is in the operating state and the Er pump light source 17 is in the stop state, the pump light generated by the Nd pump light source 15 is
The light enters the Nd / Er co-doped optical fiber 21 via the optical couplers 23 and 5. The Nd / Er co-doped optical fiber 21
Neodymium inside becomes excited state. At this time, when the signal light including the wavelengths λ ₁ and λ ₂ split by the optical splitter 2 enters the Nd · Er co-doped optical fiber 21, only the signal light of the wavelength λ ₁ is amplified, and the signal light of the wavelength λ ₂ is amplified. Decays. Therefore,
Only the signal light having the wavelength λ ₁ is transmitted from the input optical fiber 1 to the output optical fiber 13.

When the Nd excitation light source 15 is stopped and the Er excitation light source 17 is activated, the excitation light generated by the Er excitation light source 17 is Nd excitation light.
· Excite the erbium Er co-doped optical fiber 21, it becomes possible to amplify only the wavelength signals lambda ₁ of the signal. That can be transmitted to the output optical fiber 13 only the signal light of the wavelength lambda ₂ from the input optical fiber 1.

The same applies to the Nd pump light source 16, the Er pump light source 18, the optical couplers 24 and 6, and the Nd / Er co-doped optical fiber 22.
The wavelength of the signal light transmitted from the input optical fiber 1 to the output optical fiber 14 can be controlled by the operating states of the pump light source 16 and the Er pump light source 18.

Thus, by switching the excitation light incident on the Nd · Er co-doped optical fiber 21, the wavelength lambda ₁ and wavelength lambda
₂ can be separated, and the signal light of each wavelength can be transmitted to separate output optical fibers 13 and 14.

FIG. 9 is a block diagram of a wavelength division multiplexed signal light 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.

The input optical fiber 1 is connected to the input end of the optical splitter 2, and the two output ends of the optical splitter 2 are connected to the optical splitter 31, respectively.
Connected to 32 incident ends.

The two output ends of the optical splitter 31 are connected to one input ends of the optical couplers 5 and 9 via connecting optical fibers 34 and 33, respectively. An Nd excitation light source 15 and an Er excitation light source 17 are connected to the other incident ends of the optical couplers 5 and 9, respectively. The output ends of the optical couplers 5 and 9 are connected to connection optical fibers 7 and 11 respectively.
To the input end of the optical coupler 37. Optical coupler 37
The output optical fiber 13 is connected to the output end of the optical fiber.

The two output ends of the optical splitter 32 are connected to one input ends of the optical couplers 6 and 10 via connecting optical fibers 35 and 36, respectively. An Nd excitation light source 16 and an Er excitation light source 18 are connected to the other incident ends of the optical couplers 6 and 10, respectively. The output ends of the optical couplers 6 and 10 are connected to connection optical fibers 8 and 12 respectively.
Is connected to the incident end of the optical coupler. Optical coupler 38
The output optical fiber 14 is connected to the output end of the optical fiber.

In this embodiment, when the Nd pump light source 15 is in the operating state and the Er pump light source 17 is in the stop state, of the signal light branched by the optical splitter 31, the signal light incident on the Nd-doped optical fiber 7 is output. The wavelength λ ₁ component is amplified, and the Er-doped optical fiber 11
Is attenuated. If these signal light combined in optical multiplexer 37, only the signal light of the amplified wavelength lambda ₁ is outputted to the output optical fiber 13. In the opposite operation state, the signal light having the wavelength λ ₂ is obtained on the output optical fiber 13. The same applies to the output optical fiber 14 side.

〔The invention's effect〕

As described above, the wavelength division multiplexed signal light separation switching device of the present invention amplifies or attenuates the wavelength division multiplexed signal light in the rare earth element-doped optical fibers having different amplification degrees,
Only the signal light having the amplified wavelength can be transmitted to the 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-division multiplexed signal light without using a complicated electric circuit, and is particularly effective when used for optical wavelength-division multiplexing communication.

[Brief description of the drawings]

FIG. 1 is a block diagram of a wavelength division multiplexed signal light separation and switching device according to a first embodiment of the present invention. FIG. 2 is a diagram showing an example of amplification characteristics of an Nd-doped optical fiber. FIG. 3 is a diagram showing an example of a loss characteristic of an 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 a loss characteristic of an Er-doped optical fiber. FIG. 6 is a block diagram of a wavelength division multiplexed signal light 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 Nd / Er co-doped optical fiber. FIG. 8 is a diagram showing an example of a loss characteristic of an Nd / Er co-doped optical fiber. FIG. 9 is a block diagram of a wavelength division multiplexed signal light separation switching device according to a third embodiment of the present invention. FIG. 10 is a block diagram of a conventional device for separating transmitted wavelength multiplexed signal light. 1 ... input optical fiber, 2, 31, 32 ... optical splitter 3,
4, 33 to 36 ... optical fiber for connection, 5, 6, 9, 10, 2
3, 24, 37, 38 ... optical coupler, 7, 8 ... Nd-doped optical fiber, 11, 12 ... Er-doped optical fiber, 13, 14 ... output optical fiber, 15, 16 ... Nd excitation light source , 17, 18 ... Er excitation light source, 19 ... control circuit, 21, 22 ... Nd / Er co-doped optical fiber, 101, 102 ... signal source, 103, 104, 116, 117 ... light source, 105 ... … Mux, 106, 118, 119 …… Optical fiber, 10
7 ... branching device, 108, 109 ... optical wavelength filter, 110, 111
...... Light receiving elements, 112, 113 Detector circuits, 114, 115 ...... Signal amplifiers.

Claims (2)

(57) [Claims] 1. A wavelength division multiplexing signal light separation / switching apparatus comprising: a branching means for branching a wavelength multiplexed signal light; and a wavelength selecting means for transmitting light of a specific wavelength for each of the branched signal lights. The wavelength selecting means includes: a plurality of rare earth element-doped optical fibers having different wavelength characteristics of optical amplification degree; and a means for individually controlling the excited state of the plurality of rare earth element-doped optical fibers. Signal light separation switching device. 2. A wavelength division multiplexing signal light separation and switching device comprising: a branching means for branching a wavelength multiplexed signal light; and a wavelength selecting means for transmitting light of a specific wavelength for each of the branched signal lights. The wavelength selecting means includes: an optical fiber doped with a plurality of rare earth elements having different wavelength characteristics of the optical amplification degree; and a means for individually controlling an excited state of the rare earth element contained in the optical fiber. Wavelength multiplexed signal light separation switching device.