JPS62123898A - Wavelength multiplex light switchboard and wavelength multiplex light communication network - Google Patents

Abstract

PURPOSE:To obtain an accurate output wavelength of each wavelength converter by providing a reference signal generator that outputs light signals of plural kinds of wavelength and supplying the output signals to each wavelength converter. CONSTITUTION:Wavelength multiplex output light signals including direct current light of wavelength lambda1-lambda4 of a reference light generator 121 are branched by a light branching device 128 and applied to an optical waveguide 200. Direct current light of wavelength lambda1 is selected from the reference light by a wavelength selecting element 201 and supplied to a wavelength converter 206. The wavelength converter 206 changes wavelength of light signals from the wavelength selecting element 701 to make the output wavelength equal to direct current light of wavelength lambda1 from the wavelength selecting element 201. Direct current light of wavelength lambda2, lambda3, lambda4 is supplied also to wavelength converter 207, 208, 209, and each wave changing switch 207, 208, 209 changes wavelength of light signals from wavelength selecting elements 702-704 to make the output wavelength equal to supplied direct current light of wavelength lambda2, lambda3, lambda4 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a wavelength division multiplexing optical exchange for switching and connecting wavelength multiplexed optical signals, and to an optical communication network including the wavelength division multiplexing optical exchange.

(Prior Art) In recent years, demand for communication services using wideband signals such as image signals has been increasing. The bandwidth of wideband signals is several M
Since the frequency ranges from Hz to several tens of MHz, the transmission line can be replaced by a thin-diameter, wide-band, low-loss cable.
It is appropriate to introduce optical fiber cables, which have advantages such as resistance to electromagnetic induction.

Furthermore, it is considered desirable to use an optical switch that exchanges and connects optical signals from each optical fiber cable as they are without converting them into electrical signals. In particular, a wavelength division multiplexing optical switch sets communication channels between each wavelength of wavelength-multiplexed input and output optical signals. Therefore, even in communication networks, it is sufficient to transmit wavelength-multiplexed optical signals between optical exchanges using optical fiber cables, which has the advantage that the number of optical fiber cables is significantly smaller than when wavelength multiplexing is not used. There is. As such a wavelength division multiplexing optical switch, the patent application number 1982-07 shown in FIG.
The one described in the specification of No. 9388 was conventionally known. The conventional wavelength multiplexing optical switch shown in FIG. 6 includes wavelength conversion switches 600 to 602, each of which has its input connected to optical waveguides 631 to 633, and wavelength conversion switches 618 to 620, each of which has its output connected to a leading waveguide 634 to 636. Wavelength conversion switch 600~
602, and wavelength selection switches 609-617 provided between the large-blade leading wavepaths 606-608 of wavelength conversion switches 618-620. λ1. λ2.
λ3. Wavelength multiplexed optical signals of four wavelengths λ4 are inputted, and the leading waveguides 634 to 636 also output wavelengths λ1. λ2
．． λ3. A wavelength multiplexed optical signal of four wavelengths λ4 is output.

For example, a case will be described in which a communication channel is set between the two-wavelength optical signal input to the leading waveguide 633 and the optical signal of wavelength λ4 of the optical waveguide 634. Wavelength conversion switch 6
02 converts the optical signal of wavelength λ2 input to the optical waveguide 633 into wavelength λ1 under the control of a control circuit not shown here, and outputs it to the leading waveguide 605. When the wavelength λ1 is assigned as the selected wavelength of the wavelength selection switch 617 by a control circuit (not shown), the optical signal with the wavelength λ1 sent to the leading waveguide 605 is input to the wavelength conversion switch 618 guided to the waveguide 606. be done. The wavelength conversion switch 618 further converts the optical signal with the wavelength λ1 into the wavelength λ4 under the control of a control circuit (not shown), and converts the optical signal with the wavelength λ1 into the optical waveguide 6.
Output to 34.

FIG. 7 shows wavelength conversion switches 600 to 6 shown in FIG.
02 and 618 to 620. FIG.

According to FIG. 7, the wavelength conversion switch shown in FIG.
First, second, third, fourth and fifth wavelength selection elements 701, 70 in which one waveguide is cascaded with a large-blade leading waveguide.
2.703.704 and 705, this first, second,
Third and fourth wavelength selection elements 701.702.703
and 704, the input terminals are connected to the other waveguides of λ1. '12. First, second, third and fourth wavelength conversion elements 706 .with output wavelengths of λ3 and λ4.
707, 708 and 709, and this first, second, third
and an optical multiplexer 710 having a plurality of input terminals connected to the outputs of the fourth wavelength conversion elements 706, 707, 708 and 709, and the other waveguide of the wavelength selection element 705, respectively.

In FIG. 7, wavelength selection elements 701, 702, 703.
704 and 705 are control terminals 711.71, respectively.
2.713.λ1. applied to the large-blade leading waveguide 700 in response to the voltage applied to 714 and 715. λ2. λ3
For example, the LiNbO3 waveguide optical wavelength tunable filter described in the 42nd Japan Society of Applied Physics Academic Conference Proceedings 9P-M-9 is used to selectively output an optical signal of a desired wavelength from among the optical signals having a wavelength of λ4. can be used. In addition, the wavelength conversion elements 706, 707, 708 and 709 convert optical signals of arbitrary wavelengths applied to their input terminals into wavelength input 1.
．． Enter 2. 3 and λ4. As this wavelength conversion element, IEEE Jou
rnal of QB vol QE-14, No, 1
1゜No'v 1978 p810~813"pn-
p-n 0ptical Detectors and
It is possible to use a wavelength conversion element as described in ``Light-Emitting Diodes'', but this wavelength conversion element cannot convert an optical signal with a long wavelength into an optical signal with a short wavelength, so the wavelength conversion described above is not possible. Element 706
．． 707° 708 and 709 are, for example, Li
Once λ1. λ2. After generating a harmonic optical signal having a wavelength shorter than both wavelengths λ3 and λ4, the above-mentioned 'p-n
-p-n 0ptical Detect-tors a
nd Light-Emitting Diodes”
The wavelengths λl, λl, and
Enter 2. Means for converting into an optical signal having λ3 and λ4 can be considered.

In FIG. 7, for example, a control circuit (not shown) controls the second and third wavelength selection elements 702 and 703.
When the wavelengths λ2 and λ1 are respectively assigned as the selected wavelengths of After the optical signal is converted into an optical signal having
The signal is output to an output optical waveguide 716 via the .

FIG. 8 shows the wavelength selective switches 609 to 61 shown in FIG.
7 is a diagram showing a specific example of FIG. According to FIG. 8, the wavelength selective switch shown in FIG.
wavelength selection elements 801, 802, 803 and 804, and the first, second, third and fourth wavelength selection elements 80
1.802.One input is connected to the leading waveguide 805 cascade-connected to the other waveguide of 803 and 804, the other input is connected to the first Deba leading waveguide 806, and the second input is connected to the second Deba leading waveguide 8.
07, and an optical multiplexer 808 whose output is connected to each of the optical multiplexers 808 and 07, respectively.

In FIG. 8, wavelength selection elements 801, 802, 803 and 804 are connected to control terminals 809, 810, 81, respectively.
1 and 812 on the input optical waveguide 800. λ2. Among the optical signals having λ3 and λ4, a desired one wavelength is selectively outputted to the optical waveguide 805. For example, the wavelength λ on the input optical waveguide 800
1. λ2. The same wavelength λ2 of an optical signal with λ3 and λ4
and λ3 to the second leading waveguide 807.
In order to selectively output the wavelength selection elements 801, 802, 803 and 8, a control circuit (not shown)
This is done by assigning the selection wavelength λ2 to one of the wavelengths 04 and the selection wavelength λ3 to the other one.

(Problems to be solved by the invention) In the conventional wavelength multiplexing switch, the wavelength conversion switch 6 shown in FIG.
Wavelength conversion element 7 in 00-602 and 618-620
06-709 as the above 'p-n-p-n 0pti
cal Detectors and Light-Em
However, it is difficult to precisely match the output wavelength of such a wavelength conversion element to a predetermined wavelength due to variations in material composition when manufacturing the element. Fluctuations in the output wavelength also occur due to changes in the wavelength conversion element.If the output wavelength of the wavelength conversion element is not accurate, it will mix with adjacent wavelengths, making normal switching operation impossible. First, even in a communication network including a plurality of wavelength division multiplexing optical exchanges, unless the wavelengths of the optical signals sent out from each wavelength division multiplexing optical exchange match each other, communication between the optical exchanges becomes impossible.

The purpose of the present invention is to provide a wavelength multiplexing and switching device in which the wavelength of the output optical signal of a wavelength conversion switch matches a predetermined wavelength, and a wavelength division multiplexing switch in which the wavelength of the output optical signal of a wavelength conversion switch matches a predetermined wavelength. The purpose is to provide a multiplex optical communication network.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the wavelength division multiplexing optical switch provided by the present invention includes at least a wavelength conversion switch and can perform arbitrary input/output of a plurality of wavelength-multiplexed input/output optical signal highways. In a wavelength division multiplexing optical switch that sets communication channels between arbitrary wavelengths between output optical signal highways, a reference light generator that outputs optical signals of a plurality of wavelengths is further provided, and the wavelength division multiplexed light inputted in the wavelength conversion switch is further provided. It is characterized in that an optical signal having an arbitrary wavelength of the signal is converted to match an arbitrary wavelength of the output light of the reference light generator and outputted. Furthermore, the wavelength multiplexed optical communication network of the present invention includes a reference light generator that outputs optical signals of a plurality of wavelengths, and an optical signal of an arbitrary wavelength of the input wavelength multiplexed optical signal. A communication channel is set between arbitrary wavelengths between arbitrary input/output optical signal highways of a plurality of wavelength-multiplexed input/output optical signal highways, including at least a wavelength conversion switch that converts and outputs the same wavelength. It is characterized by including a plurality of wavelength division multiplexing optical switches.

(Function) In the present invention, as described above, a reference signal generator that outputs optical signals of a plurality of wavelengths is provided, and the output signal is supplied to each wavelength converter, and each wavelength converter changes the wavelength of the output optical signal. By matching one of the wavelengths of the supplied reference signal, the output wavelength of either wavelength converter can be made accurate.

Furthermore, in the present invention, one reference signal generator output optical signal is used to convert the wavelength 2 wavelength of the output optical signal of each wavelength converter in all the wavelength division multiplexing optical switches in the wavelength division multiplexing optical communication network to 1 wavelength of the reference signal. By matching the two wavelengths, it is possible to match the wavelengths of the optical signals sent out from any exchange.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a wavelength division multiplexing optical switch according to a first embodiment of the present invention, and its operation is similar to that of the conventional wavelength division multiplexing optical switch shown in FIG. In FIG. 1, the same numbers as in FIG. 6 represent the same components as in FIG.

In FIG. 1, each wavelength λ1. λ2. λ3. The output DC lights of the light sources 122, 123, 124, and 125 that oscillate at λ4 are multiplexed by the optical multiplexer 126 and sent to the leading waveguide 127 as the output of the reference light generator 121. Therefore, the output of the reference light generator 121 includes DC light having wavelengths λ1 to λ4. Wavelength conversion switches 100 to 102, and 1
The output of the reference light generator 121 is branched by an optical splitter 128 and supplied to 18 to 120, respectively.

FIG. 2 shows the first wavelength conversion switches 100 to 102 and 118 to 120 in the first embodiment of the present invention shown in FIG.
It is a figure showing a specific example. In FIG. 2, the same numbers as in the conventional wavelength conversion switch of FIG. 7 represent the same components as in FIG.

In FIG. 2, the wavelength selection elements 701 to 705 are the seventh
Similarly to the figure, depending on the voltages applied to the control terminals 711 to 715, an optical signal having a desired wavelength is selectively outputted from among the optical signals having wavelengths of λ1 to λ1 applied to the large-blade waveguide 700. Further, light obtained by branching the wavelength multiplexed output optical signal containing DC light of wavelengths λ1 to λ4 from the reference light generator 121 in FIG. Direct current light with wavelength input 1 is selected by the wavelength selection element 201 and supplied to the wavelength converter 206 from this reference light. The wavelength converter 206 wavelength-converts the optical signal from the wavelength selection element 701 so that its output wavelength becomes the same as the direct current light of wavelength λ1 from the wavelength selection element 201. The wavelength λ2. λ3゜λ4
The output wavelengths of the wavelength converters 207, 208 and 209 are each supplied with a wavelength λl.

λ2. The wavelength selection element 70 is set so that the wavelength is equal to the DC light of λ3.
The wavelength of the optical signals from 2 to 704 is converted. As a result, the output wavelengths of the wavelength converters 206 to 209 all match the output wavelengths λl to λ4 of the reference light generator 121 in FIG. 1.

Therefore, in FIG. 1, wavelength conversion switches 100 to
Since the wavelength of the output optical signal of 102 is different from λ1 to λ4, it is possible to prevent the wavelength selection switches 609 to 617 from mixing with adjacent wavelengths. Furthermore, the light source 122
By temperature-compensating only 125 to remove wavelength fluctuations due to temperature changes, it is possible to prevent fluctuations in the output wavelengths of all wavelength conversion switches due to temperature changes.

Note that in the reference light generator 121, the outputs of the light sources 122 to 125 are not multiplexed by the optical multiplexer 126, but are directly branched to the wavelength converters 206 to 209 in the wavelength conversion switches 100 to 102 and 118 to 120. Similar effects can be obtained even if each is supplied separately.

FIG. 3 is a diagram showing a specific example of the wavelength converters 206 to 209 in FIG. 2. In FIG. 3, a leading waveguide 301
An input optical signal with a wavelength λj is input into the leading waveguide 304, and a DC light with a reference wavelength λi is input into the leading waveguide 304.

The input optical signal of wavelength λi incident on the leading waveguide 301 is once converted into an electrical signal by the photoelectric conversion element 302, and then amplified by the electrical amplifier 303, and then sent to the external modulator 3.
Added to 05. The external modulator 305 is an optical waveguide 30
The DC light of wavelength λi incident from 4 is transmitted to electrical amplifier 303.
The modulated signal is modulated according to the output of and output to the leading wavepath 306.

In other words, the optical signal output from the leading waveguide 306 has a wavelength λ
It is modulated with the same information as the input optical signal of i, and the wavelength matches the wavelength λj of the reference DC light. External modulator 305
As Applied Physics Letters 1974
An optical modulator using electrical/optical effects described in Vol. 24, p. 622, or one using a semiconductor laser described in Proceedings of the 1981 National Conference of the Institute of Electronics and Communication Engineers, lecture number 873, etc. can be used.

FIG. 4 is a diagram showing a second specific example of the wavelength conversion switches 100 to 102 and 118 to 120 in the first embodiment of the present invention shown in FIG. In FIG. 4, the same numbers as in FIGS. 2 and 7 represent the same components as in FIGS. 2 and 7, respectively.

In FIG. 4, the wavelength selection element 401 outputs an optical signal having a wavelength λ1 of the optical signals having wavelengths λ1 to λ4 applied to the large-blade leading waveguide 700 to the wavelength converter 209.

Similarly, wavelength selection elements 402, 403, and 404 have wavelength λ2.
．． λ3゜λ4 optical signal to wavelength converter 208.207.2
Selectively output to 06. On the other hand, the wavelength selection elements 409 to 41
2 is DC light of a desired wavelength among the reference lights having wavelengths λ1 to λ4 applied from the reference light generator 121 in FIG. 1 to the optical waveguide 200 in accordance with the voltages applied to the control terminals 405 to 408. is selectively output to the inputs of wavelength converters 206 to 209. Wavelength converters 206-209 wavelength-convert the optical signals from wavelength selection elements 401-404 so that the output wavelengths are the same as the DC lights from wavelength selection elements 409-412, respectively.

In FIG. 4, for example, if wavelengths λ2 and λ1 are assigned as selection wavelengths of wavelength selection elements 410 and 411 by a control circuit (not shown), wavelength converter 207
, 208 are supplied with DC light of wavelengths λ2 and λ1. As a result, the optical signal with the wavelength λ2 from the wavelength selection element 402 is converted into wavelength input 1 by the wavelength converter 208, and the optical signal with the wavelength λ3 from the wavelength selection element 403 is converted into the wavelength input 1 by the wavelength converter 208.
07 to the wavelength λ2, the optical multiplexer 710
The signal is output to the Deba leading wave path 716 through the .

As described above, the wavelength conversion switch shown in FIG. 4 has the function of converting the wavelength of the optical signal of wavelengths λ1 to λ4 applied to the large-blade leading waveguide 700 and outputting it to the large-blade leading waveguide 716, and coincides with the wavelength of the reference light from the reference light generator 121 applied to the leading waveguide 200.

FIG. 5 is a diagram showing a second embodiment of the present invention, and shows a wavelength division multiplexing communication network including a plurality of wavelength division multiplexing optical switches.

In FIG. 5, a reference light generator 500 is provided with a plurality of light sources, similar to the reference light generator 121 of the first embodiment of the present invention shown in FIG. Output fiber optic cable 511.512.513
wavelength division multiplexing optical switches 501, 502, and 503, respectively.
is supplied to. Each of the wavelength division multiplexing optical exchanges 501 to 503 uses optical fiber cables 511 to 511 in place of the output light of the reference signal generator 121 in the wavelength division multiplexing optical exchange shown in FIG.
513 is used. As a result, the wavelengths of the output optical signals of the wavelength multiplexing optical exchangers 501 to 503 all match the wavelengths of the reference light output from the reference light generator 500. Furthermore, by temperature-compensating only the light source in the reference light generator 500 to eliminate wavelength fluctuations due to temperature changes, fluctuations in the output optical signal wavelengths of the wavelength multiplexing optical exchangers 501 to 503 can also be prevented. As a result, the wavelength multiplexed output optical signal of the wavelength division multiplexing optical switch 501 is transferred to the optical fiber cable 501.
1, the signal is transmitted to the wavelength multiplexing optical exchange 502 and transmitted to the wavelength conversion switch 100 via the optical waveguide 631 in FIG.
When input into the wavelength conversion switch 100, since the wavelengths are different, it is possible to prevent the wavelengths from being mixed into adjacent wavelengths within the wavelength conversion switch 100. Similarly, when the wavelength multiplexed output optical signal from the wavelength division multiplexing optical exchange 502 is transmitted to the wavelength division multiplexing optical exchange 501 via the optical fiber cable 520, it is possible to prevent mixing into adjacent wavelengths due to different wavelengths. can. Furthermore, when optical fiber cables 522 and 523 are used to connect wavelength division multiplexing optical exchangers 502 and 503, optical fiber cables 5 and 523 are connected between wavelength division multiplexing optical exchangers 503 and 501.
When connected at 24°525, communication is still possible without interference with adjacent wavelengths.

Note that the same effect can be obtained even if the outputs of the light sources in the reference light generator 500 are not multiplexed but are supplied to each wavelength multiplexing optical exchange through different destination fibers and cables for each wavelength.

(Effects of the Invention) As described above, according to the present invention, a wavelength multiplexing converter in which all the output wavelengths of the wavelength converters are the same can be obtained. Furthermore, according to the present invention, it is possible to obtain a wavelength division multiplexing optical communication network in which the wavelengths of the optical signals transmitted from the plurality of wavelength division multiplexing optical exchangers all match.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention, and FIG. 2 is a diagram showing a first embodiment of the present invention.
wavelength conversion switches 100 to 102 and 118 to 12
3 is a diagram showing a specific example of the wavelength converters 206 to 209 in FIG. 2, and FIG. 4 is a diagram showing a first specific example of the wavelength converters 206 to 209 in FIG.
18 to 120, FIG. 5 is a diagram showing the second embodiment of the present invention, FIG. 6 is a diagram showing the configuration of a conventional wavelength division multiplexing optical switch, and FIG. 7 is a diagram showing the configuration of a conventional wavelength multiplexing optical switch. A diagram showing the configuration of the wavelength conversion switches 600 to 602 and 618 to 620 in FIG. 6, and FIG. 8 shows the configuration of the wavelength selection switch 60 in FIG.
It is a figure which shows the structure of 9-617. In the figure 100~102.118~120.600~
602.618-620 are wavelength conversion switches, 121
．． 500 is a reference light generator, 122 to 125 are light sources,
126.710.808 is an optical multiplexer, 128 is an optical splitter, 201~204.401~404.409~41
9.701 to 705.801 to 804 are wavelength selection elements, 206 to 209 are wavelength converters, 302 is a charging conversion element, 303 is an electric amplifier, 305 is an external modulator,
501 to 503 each represent a wavelength division multiplexing optical switch. Question rlJ \r u) NN ~ ~ Ice side

Claims (1)

[Claims] 1. Wavelength multiplexed light that includes at least a wavelength conversion switch and sets communication channels between arbitrary wavelengths between arbitrary input and output optical signal highways of a plurality of wavelength-multiplexed input and output optical signal highways. The exchange further includes a reference light generator that outputs optical signals of a plurality of wavelengths, and converts the optical signal of any wavelength of the wavelength multiplexed optical signal inputted into the wavelength conversion switch into any of the output light of the reference light generator. A wavelength division multiplexing optical switch that converts and outputs the same wavelength. 2. A reference light generator that outputs optical signals of a plurality of wavelengths, and converts an optical signal of an arbitrary wavelength of the input wavelength multiplexed optical signal to match an arbitrary wavelength of the output light of the reference light generator. Any input/output of a plurality of wavelength-multiplexed input/output optical signal highways including at least a wavelength conversion switch that outputs
What is claimed is: 1. A wavelength division multiplexing optical communication network comprising a plurality of wavelength division multiplexing optical exchanges for setting communication channels between arbitrary wavelengths between output optical signal highways.