Light source device, light device, and control light generating method

Abstract

Configuring a device so that control light is introduced to a plurality of optical transmission lines causes the device to become large, and thus increases costs. Thus, a light source device of the present invention includes: a light generation means that generates amplified spontaneous emission; a beam splitting means that splits the amplified spontaneous emission into a plurality of split light beams; and a light control means that controls the band and power of at least one of the plurality of split light beams to generate a waveform-shaped split light beam.

Description

[Technical field]

[0001] The present invention relates to a light source device, an optical device, a control light generating method, and a transmission light generating method, and more particularly to a light source device, an optical device, a control light generating method, and a transmission light generating method used in an optical submarine cable system. [Background technology]

[0002] Optical submarine cable systems that connect continents with optical fibers play an important role as infrastructure supporting international communication networks. Optical submarine cable systems consist of submarine cables that accommodate optical fibers, submarine repeaters equipped with optical amplifiers, submarine branching devices that branch optical signals, and terminal equipment installed at landing stations.

[0003] Optical transmission equipment equipped with a reconfigurable optical add / drop multiplexing (ROADM) function that wavelength-divides or wavelength-multiplexes wavelength-multiplexed light from multiple different paths and transmits it has been introduced as an undersea branching device. An example of such an optical transmission equipment is described in Patent Document 1.

[0004] The related optical transmission device described in Patent Document 1 includes a high-speed VOA (Variable Optical Attenuator), a 1×k SPL (Splitter), an optical filter, and an ASE (Amplified Spontaneous Emission) light source. The related optical transmission device further includes a CPL (Coupler) and an M×1 WSS (Wavelength Selective Switch).

[0005] Here, the optical filter generates dummy light having an optical spectrum width similar to that of the signal light at each wavelength of the signal light from the spontaneous emission light output from the ASE light source. The 1×kSPL branches the dummy light output from the optical filter into k and outputs it toward each of the routes 1 to k. The high-speed VOA controls the optical level of the dummy light for the route determined to be abnormal so that the sum of the optical level of the signal light determined to be abnormal and the optical level of the dummy light becomes a predetermined target value.

[0006] The CPL multiplexes the signal light output to the optical transmission line of the main signal system with the dummy light output from the high-speed VOA.Then, the M×1 WSS outputs the wavelength-multiplexed light obtained by multiplexing the light output from the CPL of each path to the optical transmission line of the main signal system and the light added from the transmitter to the optical transmission line of path l.

[0007] With such a configuration, the related optical transmission device is said to be able to prevent the occurrence of optical surges and to prevent deterioration of signal light multiplexed from other paths.

[0008] Furthermore, related techniques include those described in Patent Documents 2 and 3. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2015-95808 A [Patent Document 2] JP 2012-109653 A [Patent Document 3] JP 2000-174701 A Summary of the Invention [Problem to be solved by the invention]

[0010] As described above, in the related optical transmission device described in Patent Document 1, the branched dummy light is added to the signal light from each path, and then the signals are multiplexed, and the multiplexed wavelength-multiplexed light is output to the same path. However, when adding dummy light (control light) to the main signal light output to different paths (optical transmission paths), the optical spectrum of the control light must be adjusted to the characteristics of each optical transmission path, since the wavelength dependence of loss and gain differs for each optical transmission path. Therefore, it is difficult to share the light source for the control light. Therefore, it is necessary to provide a light source for the control light for each optical transmission path to which the main signal light is output, which increases the size of the device and the cost.

[0011] In this manner, when control light is introduced into a plurality of optical transmission paths, there is a problem that the size of the device increases and the cost increases.

[0012] An object of the present invention is to provide a light source device, an optical device, a control light generating method, and a transmission light generating method that solve the problem that when control light is introduced into multiple optical transmission paths, the device becomes larger and its costs increase. [Means for solving the problem]

[0013] The light source device of the present invention includes a light generating means for generating amplified spontaneous emission light, a light branching means for branching the amplified spontaneous emission light into a plurality of branched lights, and a light control means for controlling the bandwidth and power of at least one of the plurality of branched lights to generate a waveform-shaped branched light.

[0014] The control light generating method of the present invention generates amplified spontaneous emission light, branches the amplified spontaneous emission light into a plurality of branch lights, and controls the bandwidth and power of at least one of the plurality of branch lights to generate a waveform-shaped branch light. Effect of the Invention

[0015] According to the light source device, optical device, control light generating method, and transmission light generating method of the present invention, even if a configuration is adopted in which control light is introduced into multiple optical transmission paths, it is possible to avoid an increase in the size of the device and an increase in costs. [Brief description of the drawings]

[0016] [Figure 1] 1 is a block diagram showing a configuration of a light source device according to a first embodiment of the present invention. [Diagram 2] FIG. 5 is a block diagram showing a configuration of a light source device according to a second embodiment of the present invention. [Figure 3A] 13 is a diagram showing the spectrum of amplified spontaneous emission light generated by a light generation section included in a light source device according to a second embodiment of the present invention. FIG. [Figure 3B] FIG. 11 is a diagram showing the spectrum of waveform-shaped branched light generated by a light control unit included in a light source device according to a second embodiment of the present invention. [Figure 4] FIG. 11 is a block diagram showing a configuration of a light source device according to a third embodiment of the present invention. [Diagram 5] FIG. 11 is a block diagram showing another configuration of the light source device according to the third embodiment of the present invention. [Figure 6] FIG. 11 is a block diagram showing a configuration of an optical device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0018] [First embodiment] 1 is a block diagram showing a configuration of a light source device 100 according to a first embodiment of the present invention. The light source device 100 has a light generation section (light generation means) 110, a light branching section (light branching means) 120, and a light control section (light control means) 130. The light source device 100 is preferably used in an optical submarine cable system.

[0019] The light generating section 110 generates amplified spontaneous emission light. The light branching section 120 branches the amplified spontaneous emission light into a plurality of branched lights. The light controlling section 130 controls the bandwidth and power of at least one of the plurality of branched lights to generate waveform-shaped branched light. FIG. 1 shows a configuration including a plurality of light controlling sections 130, each of which generates waveform-shaped branched light.

[0020] In this manner, in the light source device 100 of this embodiment, the optical branching section 120 branches the amplified spontaneous emission light into a plurality of branched lights, and the optical control section 130 controls the band and power of the branched lights to generate waveform-shaped branched lights. Therefore, it is possible to introduce the waveform-shaped branched lights as control lights (dummy lights) into a plurality of optical transmission paths by commonly using a single optical generation section 110. That is, according to the light source device 100 of this embodiment, even if the configuration is such that the control lights are introduced into a plurality of optical transmission paths, it is possible to avoid an increase in size and cost of the device.

[0021] Here, the light generating unit 110 can be configured to include an optical waveguide containing a rare earth element in its core, and an excitation laser that generates excitation light for exciting the rare earth element. Specifically, for example, the light generating unit 110 can be an ASE (Amplified Spontaneous Emission) light source in which an amplifier (Erbium Doped Fiber Amplifier: EDFA) using an erbium doped fiber in the optical waveguide is in a no-input signal state. Note that the amplified spontaneous emission (ASE) generated by the light generating unit 110 is amplified spontaneous emission light with a continuous and broad optical spectrum.

[0022] Typically, a multi-branch optical splitter can be used as the optical branching unit 120 .

[0023] The optical control unit 130 can be configured to include a wavelength selective switch (WSS). The wavelength selective switch (WSS) can adjust the amount of attenuation of the power of the input light for each wavelength. By configuring the wavelength selective switch (WSS) as a one-input, one-output configuration, it is possible to obtain output light in which the waveform of the input light is arbitrarily shaped.

[0024] Next, a control light generating method according to this embodiment will be described.

[0025] In the control light generating method according to the present embodiment, first, an amplified spontaneous emission light is generated. Then, the amplified spontaneous emission light is branched into a plurality of branch lights. After that, the bandwidth and power of at least one of the plurality of branch lights is controlled to generate a waveform-shaped branch light.

[0026] Here, generating the amplified spontaneous emission light may include exciting a rare earth element contained in the core of the optical waveguide with pump light, and generating the waveform-shaped branched light may include adjusting the power of at least one of the plurality of branched lights for each wavelength.

[0027] As described above, according to the light source device 100 and control light generating method of this embodiment, even if a configuration is adopted in which control light is introduced into multiple optical transmission paths, it is possible to avoid an increase in the size and cost of the device.

[0028] Second Embodiment Next, a second embodiment of the present invention will be described. Fig. 2 shows the configuration of a light source device 200 according to this embodiment. The light source device 200 further includes a connection unit (connection means) 240 in addition to a light generation unit (light generation means) 110, a light branching unit (light branching means) 120, and a light control unit (light control means) 130. The light source device 200 is preferably used in an optical submarine cable system.

[0029] The light generating section 110 generates amplified spontaneous emission light. The light branching section 120 branches the amplified spontaneous emission light into a plurality of branched lights. The light controlling section 130 controls the bandwidth and power of at least one of the plurality of branched lights to generate a waveform-shaped branched light.

[0030] The connection unit 240 is configured to introduce the waveform-shaped branched light into a plurality of interface devices 10 provided for each of the plurality of optical transmission paths 20. As the connection unit 240, typically, an optical adapter that connects optical fibers through which the waveform-shaped branched light propagates can be used.

[0031] Each of the optical transmission lines 20 includes an optical fiber transmission line. Each optical fiber transmission line may be a fiber pair (FP) including an optical fiber for an upstream line and an optical fiber for a downstream line.

[0032] Here, the optical control unit 130 can be configured to control the band and power of at least one of the plurality of branched lights in accordance with the characteristics of one of the plurality of optical transmission lines 20. A specific description will be given below with reference to the drawings.

[0033] 3A, the amplified spontaneous emission (ASE) generated by the light generating unit 110 is amplified spontaneous emission with a continuous and broad optical spectrum. This amplified spontaneous emission is branched into a plurality of branched lights by the optical branching unit 120, and each of the branched lights is introduced into the optical control unit 130. The optical control unit 130 controls the band and power of the branched lights to generate waveform-shaped branched lights.

[0034] When this waveform-shaped branched light is introduced as dummy light into the optical transmission line 20 through which the main signal light propagates, it is affected by the wavelength dependence of the loss and gain in the optical amplifiers provided in the optical fiber transmission lines and undersea repeaters that constitute the optical transmission line 20. Therefore, in the light source device 200 according to this embodiment, in order to compensate for this wavelength dependence, the optical control unit 130 is configured to control the band and power of the branched light in accordance with the characteristics of the optical transmission line 20.

[0035] Specifically, as shown in Fig. 3B, the optical control unit 130 controls the band of the branched light to either odd or even channels in Wavelength Division Multiplexing (WDM), and shapes the wave into a comb-shaped waveform. The power level of the branched light can be controlled for each channel. By using the wave-shaped branched light thus shaped, it is possible to adjust the optical signal to noise ratio (OSNR) at the receiving side to be constant for each channel.

[0036] Next, a control light generating method according to this embodiment will be described.

[0037] In the control light generating method according to the present embodiment, first, an amplified spontaneous emission light is generated. Then, this amplified spontaneous emission light is branched into a plurality of branched lights. After that, the bandwidth and power of at least one of the plurality of branched lights is controlled to generate a waveform-shaped branched light. The configuration up to this point is the same as that of the control light generating method according to the first embodiment.

[0038] In the control light generating method according to the present embodiment, the waveform-shaped branched light is further introduced into a plurality of interface devices provided for each of the plurality of optical transmission lines. In this case, when generating the waveform-shaped branched light, the bandwidth and power of at least one of the plurality of branched lights can be controlled according to the characteristics of one of the plurality of optical transmission lines.

[0039] As described above, according to the light source device 200 and the control light generating method of this embodiment, even in a configuration in which control light is introduced into multiple optical transmission paths, it is possible to avoid an increase in the size and cost of the device.

[0040] Third embodiment Next, a third embodiment of the present invention will be described. Fig. 4 shows the configuration of a light source device 300 according to this embodiment. The light source device 300 further includes a first optical amplifier (first optical amplifying means) 341 in addition to a light generation section (light generation means) 110, a light branching section (light branching means) 120, and a light control section (light control means) 130. The light source device 300 is preferably used in an optical submarine cable system.

[0041] The light generating unit 110 generates amplified spontaneous emission light. The light branching unit 120 branches the amplified spontaneous emission light into a plurality of branched lights. The light controlling unit 130 controls the bandwidth and power of at least one of the plurality of branched lights to generate waveform-shaped branched light. The first optical amplifier 341 is configured to amplify the waveform-shaped branched light.

[0042] In the light source device 300 of this embodiment, the optical branching section 120 branches the amplified spontaneous emission light into a plurality of branched lights, and the optical control section 130 generates a waveform-shaped branched light from the branched lights. Therefore, the optical power of the waveform-shaped branched light is lower than the optical power of the amplified spontaneous emission light. Therefore, the optical power of the waveform-shaped branched light may be insufficient for the optical power required by the downstream device.

[0043] However, even in such a case, the light source device 300 of this embodiment includes the first optical amplifier 341 configured to amplify the waveform-shaped branched light, and therefore can supply control light of the optical power required for a downstream device. The light source device 300 can be configured such that the first optical amplifier 341 is provided only in an optical path corresponding to a predetermined downstream device among the optical paths of a plurality of branched lights. Here, the predetermined downstream device is a downstream device that requires the input of control light having an optical power greater than the optical power of the waveform-shaped branched light.

[0044] FIG. 4 shows a configuration in which a plurality of branched lights branched by the optical branching unit 120 are introduced into the optical control unit 130. However, the present invention is not limited to this, and may be configured to include an optical path 122 that does not pass through the optical control unit 130 among a plurality of optical paths 121 of branched lights, as in the light source device 310 shown in FIG. 5. This allows the number of optical control units 130 to be reduced, thereby enabling the device to be made smaller and the cost to be reduced. Note that, as shown in FIG. 5, a second optical amplifier (second optical amplifying means) 342 may be provided in the optical path 122 that does not pass through the optical control unit 130. Here, the second optical amplifier 342 is configured to amplify at least one of the plurality of branched lights.

[0045] Next, a control light generating method according to this embodiment will be described.

[0046] In the control light generating method according to the present embodiment, first, an amplified spontaneous emission light is generated. Then, this amplified spontaneous emission light is branched into a plurality of branched lights. After that, the bandwidth and power of at least one of the plurality of branched lights is controlled to generate a waveform-shaped branched light. The configuration up to this point is the same as that of the control light generating method according to the first embodiment.

[0047] In the control light generating method according to the present embodiment, the waveform-shaped branched light may be further amplified. Also, in the control light generating method according to the present embodiment, at least one of the plurality of branched lights may be amplified.

[0048] As described above, according to the light source devices 300 and 310 and the control light generating method of the present embodiment, even if the control light is introduced into a plurality of optical transmission paths, it is possible to avoid an increase in size and cost of the device. Furthermore, it is possible to supply the control light of the optical power required for the downstream device.

[0049] [Fourth embodiment] Next, a fourth embodiment of the present invention will be described. Fig. 6 shows the configuration of an optical device 1000 according to this embodiment. The optical device 1000 includes a light source device 1100 and a plurality of interface devices 1200 provided for each of a plurality of optical transmission paths. The optical device 1000 is preferably used in an optical submarine cable system.

[0050] As the light source device 1100, any one of the light source device 100 according to the first embodiment, the light source device 200 according to the second embodiment, and the light source devices 300 and 310 according to the third embodiment can be used. Therefore, the light source device 1100 can generate at least one waveform-shaped branched light. Fig. 6 shows a case where a plurality of waveform-shaped branched lights 1001 are generated. The waveform-shaped branched lights 1001 can be introduced into each of a plurality of optical transmission paths and used as control light (dummy light).

[0051] Each of the interface devices 1200 includes an optical multiplexing section (optical multiplexing means) 1210 that multiplexes the waveform shaped branched light 1001 and the main signal light 1002. As the optical multiplexing section 1210, an optical coupler can typically be used.

[0052] Next, a method for generating transmitted light according to this embodiment will be described.

[0053] In the transmission light generating method according to the present embodiment, first, a waveform-shaped branched light is generated. Then, this waveform-shaped branched light is multiplexed with a main signal light. Here, when generating the waveform-shaped branched light, any one of the control light generating methods according to the first to third embodiments can be used.

[0054] By adopting the above-described configuration, the optical device 1000 and the transmission light generating method of this embodiment can avoid an increase in size and cost of the device even in a configuration in which control light is introduced into multiple optical transmission paths.

[0055] A part or all of the above-described embodiments can be described as, but is not limited to, the following supplementary notes.

[0056] (Supplementary Note 1) A light source device comprising: a light generating means for generating amplified spontaneous emission light; a light branching means for branching the amplified spontaneous emission light into a plurality of branched lights; and a light control means for controlling the bandwidth and power of at least one of the plurality of branched lights to generate a waveform-shaped branched light.

[0057] (Supplementary Note 2) The light source device according to Supplementary Note 1, further comprising a connection means configured to introduce the waveform-shaped branched light into a plurality of interface devices provided for each of a plurality of optical transmission paths.

[0058] (Supplementary Note 3) The light source device according to Supplementary Note 2, wherein the light control means controls a band and a power of at least one of the plurality of branched lights in accordance with characteristics of one of the plurality of optical transmission paths.

[0059] (Supplementary Note 4) The light source device according to any one of Supplementary Notes 1 to 3, further comprising a first optical amplifying means configured to amplify the waveform-shaped branched light.

[0060] (Supplementary Note 5) The light source device according to any one of Supplementary Notes 1 to 4, further comprising a second optical amplifier configured to amplify at least one of the plurality of branched lights.

[0061] (Supplementary Note 6) The light source device according to any one of Supplementary Notes 1 to 5, wherein the light generating means comprises an optical waveguide containing a rare earth element in its core, and a pumping laser that generates pumping light for exciting the rare earth element.

[0062] (Supplementary Note 7) The light source device according to any one of Supplementary Notes 1 to 6, wherein the light control means includes a wavelength selection switch.

[0063] (Supplementary Note 8) An optical device comprising: a light source device according to any one of Supplementary Notes 1 to 7; and a plurality of interface devices provided for a plurality of optical transmission paths, each of the plurality of interface devices including an optical multiplexing means for multiplexing the waveform shaped branched light and a main signal light.

[0064] (Additional Note 9) A control light generating method for generating amplified spontaneous emission light, branching the amplified spontaneous emission light into a plurality of branch lights, and controlling the bandwidth and power of at least one of the plurality of branch lights to generate a waveform-shaped branch light.

[0065] (Supplementary Note 10) The control light generating method according to Supplementary Note 9, in which the waveform-shaped branched light is introduced into a plurality of interface devices provided for a plurality of optical transmission paths, respectively.

[0066] (Supplementary Note 11) The control light generating method according to Supplementary Note 10, wherein generating the waveform-shaped branched light includes controlling a bandwidth and power of at least one of the plurality of branched lights in accordance with characteristics of one of the plurality of optical transmission paths.

[0067] (Supplementary Note 12) The control light generating method according to any one of Supplementary Notes 9 to 11, further comprising amplifying the waveform-shaped branched light.

[0068] (Supplementary Note 13) The control light generating method according to any one of Supplementary Notes 9 to 12, further comprising amplifying at least one of the plurality of branched lights.

[0069] (Supplementary Note 14) The control light generating method according to any one of Supplementary Notes 9 to 13, wherein generating the amplified spontaneous emission light includes exciting a rare earth element contained in a core of an optical waveguide with excitation light.

[0070] (Supplementary Note 15) The control light generating method according to any one of Supplementary Notes 9 to 14, wherein generating the waveform-shaped branched light includes adjusting the power of at least one of the plurality of branched lights for each wavelength.

[0071] (Supplementary Note 16) A transmission light generating method for generating the waveform-shaped branched light by the control light generating method according to any one of Supplementary Notes 9 to 15, and multiplexing the waveform-shaped branched light with main signal light.

[0072] Although the present invention has been described above with reference to the embodiment, the present invention is not limited to the above embodiment. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. [Explanation of symbols]

[0073] 100, 200, 300, 310 light source device 110 Light generation section 120 Optical branching section 121 Multiple Light Paths 122 Light Path 130 Light control section 240 Connection 341 First Optical Amplifier 342 Second Optical Amplifier 10 Interface Device 20 Optical Transmission Line 1000 optical equipment 1001 Waveform shaping branching light 1002 Main signal light 1100 Light source device 1200 Interface Device 1210 Optical multiplexing section

Claims

1. A light generating means for generating amplified spontaneous emission light; an optical branching unit for branching the amplified spontaneous emission light into a plurality of branch lights propagating through a plurality of optical transmission paths; an optical control unit that controls a band and a power of at least one of the plurality of branched lights to generate a waveform-shaped branched light; a connection means configured to introduce the waveform-shaped branched light into a plurality of interface devices provided for each of the plurality of optical transmission paths, The optical control means controls a band and a power of at least one of the plurality of branched lights in accordance with a characteristic of one of the plurality of optical transmission paths. Light source device.

2. Further comprising a first optical amplifying means configured to amplify the waveform-shaped branched light.

2. The light source device according to claim 1.

3. Further comprising a second optical amplifier configured to amplify at least one of the plurality of branched lights.

3. A light source device according to claim 1 or 2.

4. The light generating means includes an optical waveguide including a rare earth element in a core, and a pumping laser that generates pumping light for exciting the rare earth element.

4. A light source device according to claim 1.

5. The optical control means comprises a wavelength selective switch.

5. A light source device according to claim 1.

6. A light generating means for generating amplified spontaneous emission light; an optical branching unit for branching the amplified spontaneous emission light into a plurality of branch lights propagating through a plurality of optical transmission paths; an optical control unit that controls a band and a power of at least one of the plurality of branched lights to generate a waveform-shaped branched light; and a plurality of interface devices provided for each of the plurality of optical transmission paths, Each of the plurality of interface devices includes an optical multiplexing means for multiplexing the waveform shaped branched light and the main signal light. light device.

7. The optical fiber further includes a connection means configured to introduce the waveform-shaped branched light into each of the plurality of interface devices.

7. An optical device according to claim 6.

8. The optical control means controls a bandwidth and a power of at least one of the plurality of branched lights in accordance with a characteristic of one of the plurality of optical transmission paths.

8. An optical device according to claim 7.

9. Further comprising a first optical amplifying means configured to amplify the waveform-shaped branched light. An optical device according to any one of claims 6 to 8.

10. generating amplified spontaneous emission light; branching the amplified spontaneous emission light into a plurality of branch lights propagating through a plurality of optical transmission paths; generating a waveform-shaped branched light by controlling a band and a power of at least one of the plurality of branched lights in accordance with a characteristic of one of the plurality of optical transmission lines; The waveform-shaped branched light is introduced into a plurality of interface devices provided for each of the plurality of optical transmission paths. Control light generation method.

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