WO2025257879A1 - Circuit optique - Google Patents

Circuit optique

Info

Publication number
WO2025257879A1
WO2025257879A1 PCT/JP2024/021025 JP2024021025W WO2025257879A1 WO 2025257879 A1 WO2025257879 A1 WO 2025257879A1 JP 2024021025 W JP2024021025 W JP 2024021025W WO 2025257879 A1 WO2025257879 A1 WO 2025257879A1
Authority
WO
WIPO (PCT)
Prior art keywords
combiners
signal light
optical circuit
waveguides
port
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2024/021025
Other languages
English (en)
Japanese (ja)
Inventor
慶太 山口
賢哉 鈴木
摂 森脇
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NTT Inc
NTT Inc USA
Original Assignee
Nippon Telegraph and Telephone Corp
NTT Inc USA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Telegraph and Telephone Corp, NTT Inc USA filed Critical Nippon Telegraph and Telephone Corp
Priority to PCT/JP2024/021025 priority Critical patent/WO2025257879A1/fr
Publication of WO2025257879A1 publication Critical patent/WO2025257879A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/125—Bends, branchings or intersections
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/30—Optical coupling means for use between fibre and thin-film device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
    • H01S3/067—Fibre lasers

Definitions

  • the present invention relates to optical signal processing, and more specifically to optical circuits for spatial multiplexing transmission.
  • SDM spatial division multiplexing
  • MMF uncoupled multicore fiber
  • Spatial multiplexing transmission systems require higher performance in the elemental technologies of optical transmission media, optical node devices, and optical transmitter/receiver transmission devices.
  • a particular issue is that the number of optical amplifiers required increases with the number of spatial channels, especially for MCFs and multiple SCFs. While one fiber amplifier per ordinary SMF is sufficient, spatial multiplexing transmission systems require one amplifier per spatial channel, resulting in increased costs and footprint.
  • Figure 1 shows the conceptual configuration of a fiber amplifier for an MCF.
  • fiber amplifier 50 is configured to optically amplify signal light 23 propagating through MCF 101, which has four cores, and output the amplified signal light 24 to MCF 101.
  • pump light excitation light
  • SCFs 120-1 to 120-4 which are rare-earth fibers widely used in optical amplification
  • combiners 103-1 to 103-4 that combine the pump light and combiners 105-1 to 105-4 that remove the pump light are required for each signal light.
  • fan-out 51 and fan-in 52 are required to optically connect each core of the MCF to the combiner.
  • the fan-out 51 spatially expands the cores of MCF 101, which are spaced about tens of microns apart, to the waveguide spacing of the combiner, while the fan-in 52 spatially converges the cores from the waveguide spacing of the combiner back to the core spacing of MCF 107. It is not easy to integrate a configuration in which a combiner is inserted between MCFs 101 and 107 and the amplifying SCFs 120-1 to 120-4 to connect them in a compact design.
  • Non-Patent Document 1 A simpler configuration has also been proposed in which the multiple SCFs used for amplification in the configuration shown in Figure 1 are replaced with a single MCF rare-earth doped fiber.
  • this configuration is no different from the configuration shown in Figure 1 in that it requires as many combiners as there are spatial channels (number of cores) to connect the pump light, and therefore requires integration in conjunction with fan-in and fan-out.
  • Raman amplifiers which require the input of pump light.
  • Raman amplifiers do not use rare-earth fiber, but the need to input pump light and signal light into the same fiber is the same as fiber amplifiers, and a number of combiners equal to the number of spatial channels is required.
  • the present invention was made in consideration of the above-mentioned problems, and its purpose is to provide an integrated optical circuit suitable for optically amplifying signal light propagating through multiple cores.
  • One aspect of the present invention comprises a plurality of combiners arranged in an array, each having a first port for signal light, a second port for pump light, and a third port for the signal light and the pump light, and a pitch adapter formed parallel to the substrate surface that converts the spacing between a plurality of waveguides for the signal light to the spacing between the first ports of the plurality of combiners, the plurality of combiners and the pitch adapter being an optical circuit integrated on a single chip.
  • Another aspect of the present invention is an optical circuit comprising a plurality of combiners arranged in an array, each having a first port for signal light, a second port for pump light, and a third port for the signal light and the pump light; a first pitch adapter that converts the spacing of a plurality of waveguides for the signal light formed parallel to the substrate surface to the spacing of the first ports of the plurality of combiners; and a second pitch adapter that converts the spacing of a plurality of waveguides for the amplified signal light, wherein the plurality of combiners, the first pitch adapter, and the second pitch adapter are integrated on a single chip, and the cross sections of the waveguides at the third ports of the plurality of combiners and the cross section of the waveguide on the wider side of the second pitch adapter are on a common end face.
  • a further aspect of the present invention is a fiber optic optical fiber comprising: a first plurality of combiners arranged in an array, each having a first port for signal light, a second port for pump light, and a third port for the signal light and the pump light; a first pitch adapter that adjusts the spacing of a plurality of waveguides for the signal light formed parallel to the substrate surface to the spacing of the first ports of the first plurality of combiners; and a first pitch adapter that adjusts the spacing of a plurality of waveguides for the signal light formed parallel to the substrate surface to the spacing of the first ports of the first plurality of combiners.
  • the first plurality of combiners, the second plurality of combiners, the first pitch adapter, and the second pitch adapter are integrated on a single chip, and the cross sections of the waveguides of the third ports of the first plurality of combiners and the cross sections of the waveguides of the third ports of the second plurality of combiners are on a common end face.
  • An integrated optical circuit is provided that is suitable for optically amplifying signal light propagating through multiple cores.
  • FIG. 1 is a diagram showing a conceptual configuration of a fiber amplifier for an MCF.
  • 1 is a diagram illustrating a configuration of a fiber amplifier including an optical circuit according to a first embodiment.
  • 1 is a diagram showing an end face structure on the side where signal light is input and output of the optical circuit of the first embodiment.
  • FIG. 3A and 3B are diagrams illustrating a connection between an optical circuit of the first embodiment and an amplification fiber.
  • FIG. 10 is a diagram showing the configuration of a fiber amplifier including an optical circuit according to a second embodiment.
  • FIG. 10 is a diagram showing the configuration of a fiber amplifier including an optical circuit according to a third embodiment.
  • FIG. 10 is a diagram showing the configuration of a fiber amplifier including an optical circuit according to a fifth embodiment.
  • FIG. 10 is a diagram showing the configuration of another fiber amplifier including an optical circuit according to the fifth embodiment.
  • FIG. 10 is a diagram showing the configuration of a fiber amplifier including an optical circuit according to a sixth embodiment.
  • FIG. 13 is a diagram showing the configuration of a fiber amplifier including an optical circuit according to a seventh embodiment.
  • FIG. 13 is a diagram showing another configuration of a fiber amplifier including an optical circuit according to the seventh embodiment.
  • FIG. 13 is a diagram showing another configuration of a fiber amplifier including an optical circuit according to the seventh embodiment.
  • the following description discloses an optical circuit with an integrated configuration that optically amplifies signal light propagating through multiple cores, which can be used in a spatial multiplexing transmission system in which nodes are connected by MCF.
  • the optical circuit disclosed herein comprises multiple combiners arranged in an array and a pitch adapter that matches the spacing of multiple waveguides for signal light formed parallel to the substrate surface to the spacing of the first ports for signal light of the multiple combiners.
  • the multiple combiners and pitch adapter are integrated on a single chip, and if an amplification optical fiber is further included, a fiber amplifier is realized.
  • Two separate optical circuits with the same configuration can be connected by an amplification optical fiber so that corresponding combiners face each other.
  • Two optical circuits with the same or similar configuration can also be integrated on a single chip, and corresponding combiners can be connected by an amplification optical fiber at a single chip end face.
  • an MCF with two or more cores can be connected as the input or output fiber for the signal light.
  • the amplification optical fiber connected to the optical circuit may be multiple SCFs, or, if an additional pitch adapter is provided, may be one or more SCFs.
  • FIG. 2 is a diagram illustrating the configuration of a fiber amplifier including an optical circuit according to the first embodiment.
  • the fiber amplifier 100 optically amplifies signal light 23 propagating through an MCF 101 and outputs the amplified signal light 24 to an MCF 107.
  • the fiber amplifier 100 includes two integrated optical circuits 10-1 and 10-2 and multiple amplification fibers 104 connecting the two optical circuits.
  • the signal light 23 is simply represented by a single arrow, representing multiple independent signal lights corresponding to the multiple cores included in the MCF 101.
  • the amplified signal light 24 is also represented by a single arrow representing multiple signal lights.
  • optical circuit 10-1 At least pitch adapter 102 and multiple combiners 103 are integrated onto a single substrate. In Figure 2(a), these components are shown separated by dotted lines for ease of explanation of their functions, but the entire optical circuit 10-1 is fabricated as a single unit. As will be described later, optical circuits 10-1 and 10-2 have the same basic configuration, and optical circuit 10-1 can be rotated 180 degrees to become optical circuit 10-2.
  • the pitch adapter 102 adjusts the spacing between the multiple waveguides 13-1, which are configured to connect to the multiple cores of the MCF 101 at the chip end face, to the spacing between the waveguides 13-2 near each of the multiple combiners 103.
  • the core spacing in a typical MCF is several tens of micrometers.
  • the repetition pitch of the arrayed combiners is approximately several hundreds of micrometers to 1 mm. Therefore, in the optical circuit 10-1 connected to the input MCF 101, the pitch adapter 102 serves as an expansion section that widens the waveguide spacing.
  • the pitch adapter 106 serves as a convergence section that narrows the waveguide spacing.
  • the pitch adapters 102 and 106 in Figure 2(a) above correspond to the fan-out 51 and fan-in 52 in the conventional configuration described in Figure 1.
  • the pitch adapter 102 in Fig. 2A the length in the z-axis direction of the portion that widens the waveguide spacing is depicted as being much shorter than the distance to the combiner 103.
  • Fig. 2A is a schematic diagram, and the spacing between the multiple waveguides is smoothly expanded from the chip end face toward the combiner, following a rational pattern arrangement of the optical circuit.
  • the multiple combiners 103 combine signal light with pump light (excitation light) from a light source (not shown) and output combined light of the signal light and pump light.
  • (b) of Figure 2 shows the functional configuration of one of the multiple combiners 103, combiner 103-1.
  • Combiner 103-1 of optical circuit 10-1 has a port (first port) to which signal light is input, a port (second port) to which pump light is input, and a port (third port) that outputs combined light of the signal light and pump light.
  • (c) of Figure 2 shows the functional configuration of one of the multiple combiners 105, combiner 105-1.
  • Combiner 105-1 of optical circuit 10-2 has a port (third port) to which the combined light of the amplified signal light and pump light is input, a port (second port) that demultiplexes and outputs only the pump light, and a port (first port) that outputs the amplified signal light.
  • the "ports" of the combiner described in Figures 2(b) and (c) do not refer to the existence of physical optical input and output points, but rather to the optical multiplexing and demultiplexing functions.
  • the ports refer to the waveguides.
  • the waveguides continue as they are, pass through a pitch adapter, reach the end face of the optical circuit, and then reach the optical branch.
  • the port spacing essentially refers to the spacing between the waveguides that make up the combiner.
  • the optical circuit disclosed herein comprises a plurality of combiners 103 arranged in an array, each having a first port for signal light 23, a second port for pump light 20, and a third port for the signal light and the pump light, and a pitch adapter 102 formed parallel to the substrate surface that converts the spacing between a plurality of waveguides 13-1 for the signal light to the spacing between the first ports of the plurality of combiners, and the plurality of combiners and the pitch adapter can be implemented as an optical circuit integrated on a single chip.
  • Pump light 20 is supplied to each of the multiple combiners 103 from a pump light source not shown in Figure 2(a). Furthermore, pump light 21 separated from the multiple combiners 105 can be dissipated outside the optical circuit 10-2.
  • a pitch adapter and multiple combiners arranged in an array are each integrated on a single substrate.
  • "arranged in an array” means that multiple combiners are efficiently and orderly laid out on the optical circuit chip. Therefore, it is not necessary for the combiners to be laid out precisely in a line at regular, even intervals.
  • the multiple combiners 103 and 105 it is rational to lay out the multiple waveguides from the ports for combining the signal light and pump light so that they are lined up at equal intervals on the chip end face, from the standpoint of ease of assembly with the optical fiber array.
  • a configuration in which two optical circuits 10-1 and 10-2 are further integrated into a single chip will be described later as embodiment 7.
  • Efficient integration is possible by configuring all components of the optical circuit as waveguides.
  • Pitch adapters 102 and 106 can utilize optical circuits that convert the waveguide spacing.
  • the fiber amplifier 100 operates by supplying pump light 20 to each combiner 103 and connecting an amplification fiber 104 between the two optical circuits 10-1 and 10-2.
  • a rare-earth doped fiber can be used as the amplification fiber 104.
  • One example is an erbium-doped fiber amplifier (EDFA).
  • Rare-earth elements include praseodymium and thulium in addition to erbium.
  • the amplification fiber 104 is described as a single co-fiber, i.e., multiple SCFs.
  • the performance of the fiber amplifier using rare-earth doped fiber for MCF shown in Non-Patent Document 1 is still insufficient. If the number of channels to be spatially multiplexed, i.e., the number of cores in the input MCF, is around 10 or less, it is easy to provide the same number of SCF amplification fibers 104.
  • the combiner 103-1 that combines the pump light and signal light can be configured to use a conventional waveguide coupler to combine the lights, or a wavelength division multiplexing (WDM) coupler that takes advantage of the difference in wavelength between the pump light and signal light. While conventional couplers inherently result in power loss when combining lights, the use of a WDM coupler theoretically allows for loss-free combining.
  • WDM wavelength division multiplexing
  • the combiner 105-1 which removes only the pump light from the combined light, must be separated by wavelength using a WDM coupler. If the pump light is sufficiently attenuated in the amplification fiber 104 or other areas, the combiner 105, which removes the pump light from the combined light, can be omitted.
  • Normal couplers include directional couplers, Mach-Zehnder interferometers (MZI), Y-junctions, and multi-mode interference (MMI) waveguides.
  • WDM couplers that can be used include directional couplers and MZIs. Other waveguide-type WDM couplers can also be used.
  • FIG. 3 is a diagram showing the cross-sectional structure of the optical circuit of the first embodiment on the input/output side of the signal light.
  • the connection surface (line III-III) between the core of the input-side MCF 101 and the narrow portion of the waveguide 13-1 of the pitch adapter 102 is viewed.
  • FIG. 3A shows the cross section (x-y plane) of the fiber 101-1 when the input-side MCF has two cores, and the structure of the opposing end face (x-y plane) of the optical circuit 10a.
  • the optical circuit 10a includes an underclad 12, waveguide cores 13a and 13b, and an overclad 14-1 formed on a substrate 11.
  • the angle of the MCF 101-1 is adjusted so that the two cores 121a and 121b are parallel to the substrate surface (x-z plane), and the spacing between the cores 121a and 121b matches the spacing between the cores 13a and 13b of the optical circuit 10a.
  • the cores 13a and 13b can be arranged in a row at the end face. Even if the MCF has three or more cores, as long as the cores are arranged in a row at the end face of the optical circuit, the MCF and the optical circuit of the present disclosure can be connected in the same manner as in (a) of FIG.
  • Figure 3(b) shows the cross section (x-y plane) of fiber 101-2 when the input MCF has four cores, and the structure of the opposing end face (x-y plane) of optical circuit 10b.
  • Optical circuit 10b has a two-layer waveguide structure on underclad 12 formed on substrate 11.
  • the first layer comprises cores 13a and 13b and overclad 14-1, while the second layer comprises cores 13c and 13d and overclad 14-2.
  • Waveguide structures with three or more layers are also possible.
  • Figure 2(a) shows an example of the connection between the input-side MCF 101 and optical circuit 10-1, but the connection between the output-side MCF 107 and optical circuit 10-2 is exactly the same.
  • an example was shown in which a single MCF 101, 107 is used to transmit multiple signal lights between nodes, but in a spatial multiplexing transmission system, multiple SCFs can also be used to transmit signal lights.
  • the optical connection between the fiber and pitch adapter can be made by arranging multiple SCFs in a one-dimensional manner.
  • the spacing between the waveguide cores on the optical circuit side can be adjusted to match the spacing between the array of multiple SCFs, allowing them to be arranged in a single row, as in Figure 3(a). This is the same as the PLC structure of prior art, and is the simplest configuration.
  • FIG. 4 is a diagram illustrating the connection of the optical circuit of the first embodiment to an amplification fiber.
  • (a) of FIG. 4 shows a fiber amplifier 200 in which the amplification fiber and the optical circuit are connected using fiber blocks 108a and 108b.
  • the basic configuration of the optical circuits 10-1 and 10-2 is the same as that of the fiber amplifier 100 in (a) of FIG. 2.
  • (b) of FIG. 4 shows a cross section (x-y plane) of the amplification fiber 104 taken along line IVb-IVb.
  • the MCFs 101 and 107 each have six cores and are connected to three layers of waveguide cores at each end face of the optical circuits 10-1 and 10-2.
  • the narrow portion of the waveguide 13-1 of the pitch adapter 102 has a three-layer structure, which adds one layer to the structure in (b) of FIG. 3.
  • the waveguide 13-1 at the end face connecting to the MCF 101 expands while maintaining its height in each layer and is connected to the corresponding combiner in each layer. Therefore, the connection of multiple combiners 103 to corresponding amplification fibers 104 is made at different heights using the fiber block 108a.
  • the signal light entering the waveguide in the first layer of the optical circuit passes through the corresponding combiner and is connected to amplification fiber 104-1 in the deepest groove 109-1.
  • the signal light entering the waveguide in the second layer of the optical circuit passes through the corresponding combiner and is connected to amplification fiber 104-2 in the second deepest groove 109-2.
  • the signal light entering the waveguide in the third layer of the optical circuit passes through the corresponding combiner and is connected to amplification fiber 104-3 in the third deepest groove 109-3.
  • the six fibers are drawn at uneven intervals due to the greatly enlarged view in the height direction, but for ease of operation, they can be arranged as an equally spaced fiber array. Both ends of the amplification fiber 104 can be similarly fixed in advance with fiber blocks.
  • the waveguides from multiple combiners 103 can be connected to the amplification optical fibers 104 in a single alignment process.
  • the number of parts can be reduced.
  • FIG. 5 is a diagram showing the configuration of a fiber amplifier including an optical circuit according to the second embodiment.
  • a laser diode (LD) or the like is used as the pump light source.
  • the optical circuit 10-1 in FIG. 5 is shown in an inverted L-shape, but this does not represent a chip shape.
  • the components of the optical circuits 10-1 and 10-2 in FIG. 5 are shown separated by dotted lines, but are configured as a single unit.
  • the fiber amplifier 300 in Figure 5 further integrates an optical branch 111 into the input-side optical circuit 10-1, allowing branched pump light to be supplied to multiple combiners.
  • an optical branch 111 By providing a high-output pump light source 110 and optical branch 111, the pump light can be branched and supplied to each of multiple combiners 103, allowing it to be multiplexed into signal light of multiple spatial channels. This can be achieved by using a waveguide coupler as the optical branch 111, and by integrating it on the same chip as multiple combiners 103, the number of light sources and components can be reduced.
  • the combiner 105 can be omitted.
  • the pump light from multiple combiners 105 is not depicted, but it shows that the pump light is attenuated. Therefore, the optical circuit 10-2 in Figure 5 can omit all combiners 105 and use only the pitch adapter 106.
  • FIG. 6 is a diagram showing the configuration of a fiber amplifier including an optical circuit according to embodiment 3.
  • embodiments 1 and 2 examples of fiber amplifiers in which pump light 20 is input from the same direction as the signal light are shown.
  • the fiber amplifier also operates when pump light is input from the opposite propagation direction to the signal light.
  • pump light is input from multiple combiners 105 in the output-side optical circuit 10-2 and propagates through multiple amplification fibers 104 in the opposite direction to the propagation direction of the signal light 23.
  • an isolator that transmits light in only one direction may be used instead of the multiple combiners 103 in the optical circuit 10-1.
  • the isolator does not need to be on the chip of the optical circuit 10-1.
  • a fiber isolator can be used between the amplification fiber 104 and the optical circuit 10-1.
  • a configuration in which pump light propagates in the opposite direction to the signal light being amplified, as in the fiber amplifier 400 of this embodiment, is not limited to fiber amplifiers, but can also be applied to Raman amplifiers. Therefore, the optical circuits 10-2 and 10-1 disclosed herein can also be used to integrate Raman amplifiers.
  • the size of the propagation mode that propagates is often different between the waveguide of the optical circuit and the core of the SCF, MCF, or amplification fiber that inputs and outputs the signal light. If the optical circuit and the fiber are connected while the difference in the size of the propagation mode remains, the mismatch in the size of the propagation mode will cause loss.
  • optical loss can be reduced by providing a spot size converter that converts the size of the propagation mode in the waveguide near the connection end face with the fiber.
  • Spot size converters include those that form segments in the waveguide and those that have a shape that gradually changes the thickness of the waveguide.
  • GFF gain flattening filter
  • Figure 7 shows the configuration of a fiber amplifier including an optical circuit according to embodiment 5.
  • the overall configuration of fiber amplifier 500-1 in Figure 7 is generally the same as that of fiber amplifier 300 including an optical circuit according to embodiment 2 shown in Figure 5.
  • the configuration of optical circuits 10-1 and 10-2 is exactly the same as that of embodiment 2.
  • the difference is that a GFF 115 is connected to each of multiple amplification fibers 104.
  • the GFF has an element configured with an input fiber and an output fiber.
  • One fiber of amplification fiber 104-1 and GFF 105-1 can be connected to each other, and the other fiber of the GFF can be connected to the waveguide of the combiner of optical circuit 10-2.
  • Figure 8 shows another configuration of a fiber amplifier including the optical circuit of embodiment 5.
  • the overall configuration of the fiber amplifier 500-2 in Figure 8(a) is generally the same as the fiber amplifier 500-1 shown in Figure 7.
  • the GFF 115 is integrated on a chip in the optical circuit 10-2 connected to the output MCF 107.
  • FIG. 10-2 shows a cross section (y-z plane) passing through line VIIIb-VIIIb along a waveguide including the GFF 115 of the optical circuit 10-2.
  • the optical circuit 10-2 is composed of an underclad 12, a core 13, and an overclad 14 on a substrate 11.
  • a groove is formed perpendicular to the light propagation direction in the core 13 of the waveguide, and a GFF 115 is inserted into the groove.
  • the GFF can be composed of a dielectric multilayer film, and a plate-shaped one that can be inserted into the groove can be used.
  • a separate GFF is shown inserted into each of the waveguides corresponding to the multiple amplification fibers 104.
  • a single GFF 115 may also be inserted across all of the waveguides connected to the amplification fibers 104.
  • a GFF using a waveguide-type element can be realized, for example, by connecting MZI circuits in multiple stages, or by using other interferometers such as ring resonators.
  • the degree of integration can be further improved by fabricating it on the same chip as combiner 105 of optical circuit 10-2, etc.
  • all combiners 105 in the optical circuit 10-2 in Figure 7 can be omitted, leaving only the pitch adapter 106.
  • all combiners 105 in the optical circuit 10-2 in Figure 8 can be omitted, leaving only the pitch adapter 106 and GFF 115.
  • Figure 9 shows the configuration of a fiber amplifier including an optical circuit according to embodiment 6.
  • Figure 9(a) shows fiber amplifier 600-1, which has an integrated variable optical attenuator (VOA).
  • Figure 9(b) shows fiber amplifier 600-2, which has a different configuration and an integrated VOA. Both fiber amplifiers have roughly the same configuration as optical circuits 10-1 and 10-2 of fiber amplifier 300 in Figure 5.
  • VOA variable optical attenuator
  • a VOA 120 is provided for each branch output of the optical branch 111.
  • VOA optical waveguide
  • An optical waveguide VOA such as one using an MZI can be used.
  • a waveguide-type variable optical branch 114 with an adjustable branching ratio is used, allowing gain adjustment while making more effective use of the light from the pump light source than optical branches with a fixed branching ratio.
  • a configuration using an MZI can also be used for the waveguide-type variable optical branch 114 (Non-Patent Document 2).
  • all of the combiners 105 in the optical circuit 10-2 in Figure 9 can be omitted, leaving only the pitch adapter 106.
  • the fiber amplifier is composed of two separate optical circuits 10-1 and 10-2 and a plurality of amplification fibers 104.
  • the fiber amplifier is composed of two separate optical circuits 10-1 and 10-2 and a plurality of amplification fibers 104.
  • Figure 10 shows the configuration of a fiber amplifier including an optical circuit according to embodiment 7.
  • the fiber amplifier 700 in Figure 10 integrates the two optical circuits 10-1 and 10-2 of embodiment 6 shown in Figure 9(b) into a single optical circuit 10 on a chip. Elements are arranged to fold the signal path so that the end faces connected to multiple amplification fibers 104 form a single common end face.
  • the input MCF 101 for the signal light and the output MCF 107 for the amplified signal light are also connected to a single common end face.
  • the MCFs 101 and 1017 for the signal light and the multiple amplification fibers 104 are connected at different end faces.
  • the overall shape of the chip 10 is shown as an inverted L-shape, but this does not represent the actual chip shape.
  • the MCFs 101 and 107 for signal light can be combined into a single fiber block, allowing connection to the chip in a single process.
  • the amplification fiber 104 can also be folded back to combine the input and output ends into a single fiber block, allowing connection to the chip in a single process. This simplifies the manufacturing process when assembling a fiber amplifier.
  • Figure 11 shows another configuration of a fiber amplifier including the optical circuit of embodiment 7.
  • the fiber amplifier 700-2 in Figure 11 is the optical circuit of Figure 10, with all of the multiple combiners 105 connected to the output MCF 107 omitted. If the pump light is sufficiently attenuated in the amplification fiber 104 or other areas, the combiner 105 that removes the pump light from the signal light can be omitted. By reducing the number of integrated elements compared to the optical circuit of Figure 10, it is possible to achieve a smaller chip size and lower costs.
  • the optical circuit disclosed herein can also be implemented as an optical circuit comprising a plurality of combiners 103 arranged in an array, each having a first port for signal light, a second port for pump light, and a third port for the signal light and the pump light; a first pitch adapter 102 that converts the spacing between the plurality of waveguides for the signal light formed parallel to the substrate surface to the spacing between the first ports of the plurality of combiners; and a second pitch adapter 106 that converts the spacing between the plurality of waveguides for the amplified signal light, wherein the plurality of combiners, the first pitch adapter, and the second pitch adapter are integrated on a single chip, and the cross sections of the waveguides at the third ports of the plurality of combiners and the cross section of the waveguide with the wider spacing of the second pitch adapter are on a common end face.
  • Figure 12 shows yet another configuration of a fiber amplifier including the optical circuit of embodiment 7.
  • the fiber amplifier 700-2 in Figure 12 is configured in the optical circuit of Figure 10 such that the MCFs 101 and 107 for signal light and the amplification fiber 104 are all connected at a single end face of the chip. If the fiber 116 from the pump light source 110 is also connected at the same end face, it becomes possible to connect all of the fibers required for the fiber amplifier together in a single fiber block.
  • the alignment and connection of the optical circuit 10 and all of the fibers can be performed in a single process.
  • the order from top to bottom is output amplification fiber, output MCF, input MCF, input amplification fiber, and pump light fiber, but this is not limiting. Also, as explained in embodiment 2, the combiner 105 that removes pump light from signal light can be omitted.
  • MCFs can be used instead of SCFs.
  • the waveguides connected to the combiner's ports for signal light and pump light can be adapted to the core spacing of the MCFs again.
  • another pitch adapter that narrows the waveguide spacing can be provided on the amplification fiber 104 side of optical circuit 10-1 in Figure 2(a). If the number of spatial channels is small, a single MCF can be used as the amplification fiber.
  • the optical circuit disclosed herein is suitable for optically amplifying signal light propagating through multiple cores.
  • This invention can be used in optical signal processing.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Plasma & Fusion (AREA)
  • Optical Couplings Of Light Guides (AREA)

Abstract

Est divulgué un circuit optique qui a une configuration intégrée pour amplifier optiquement une lumière de signal propagée à travers une pluralité d'âmes dans un système de transmission multiplex spatial dans lequel des nœuds sont connectés par une MCF.　Des circuits optiques (10-1, 10-2) selon la présente divulgation comprennent : une pluralité de combineurs (103, 105) disposés dans un réseau ; et des adaptateurs de pas (102, 106) qui correspondent à l'espacement entre une pluralité de guides d'ondes formés pour une lumière de signal de manière à être parallèles à une surface de substrat avec l'espacement entre des premiers ports de la pluralité de combineurs pour la lumière de signal. La pluralité de combineurs (103, 105) et les adaptateurs de pas (102, 106) sont intégrés sur une seule puce, et un amplificateur à fibre (100) peut être mis en œuvre s'il est en outre pourvu d'une fibre optique d'amplification (104). Les deux circuits optiques individuels (10-1, 10-2), qui ont la même configuration, peuvent être connectés par la fibre optique d'amplification (104) de telle sorte que des combineurs correspondants (103, 105) se font face. Deux circuits optiques qui ont la même configuration ou une configuration similaire peuvent être intégrés sur une seule puce, et des combineurs correspondants peuvent être connectés par une fibre optique d'amplification sur une surface d'extrémité de puce.
PCT/JP2024/021025 2024-06-10 2024-06-10 Circuit optique Pending WO2025257879A1 (fr)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005506696A (ja) * 2001-10-17 2005-03-03 インテル・コーポレーション 集積されたアレイ型波長回折格子（ａｗｇ）を有する光集積回路
CN102902024A (zh) * 2012-09-29 2013-01-30 华中科技大学 实现多芯光纤和光电子芯片阵列光耦合的方法
JP2014507796A (ja) * 2010-12-29 2014-03-27 アルカテル−ルーセント マルチコア光ファイバ用光増幅器
US20170279242A1 (en) * 2016-03-22 2017-09-28 Nec Laboratories America, Inc. 3-dimensional inscripted wdm coupler for optical amplifiers and methods for using 3-dimensional inscripted wdm couplers in networks
US20180375289A1 (en) * 2016-03-09 2018-12-27 Huawei Technologies Co., Ltd. Optical coupling connector, optical coupling system, and waveguide coupling method
US20220404555A1 (en) * 2021-06-22 2022-12-22 Corning Research & Development Corporation Optical assembly for coupling with two-dimensionally arrayed waveguides and associated methods

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005506696A (ja) * 2001-10-17 2005-03-03 インテル・コーポレーション 集積されたアレイ型波長回折格子（ａｗｇ）を有する光集積回路
JP2014507796A (ja) * 2010-12-29 2014-03-27 アルカテル−ルーセント マルチコア光ファイバ用光増幅器
CN102902024A (zh) * 2012-09-29 2013-01-30 华中科技大学 实现多芯光纤和光电子芯片阵列光耦合的方法
US20180375289A1 (en) * 2016-03-09 2018-12-27 Huawei Technologies Co., Ltd. Optical coupling connector, optical coupling system, and waveguide coupling method
US20170279242A1 (en) * 2016-03-22 2017-09-28 Nec Laboratories America, Inc. 3-dimensional inscripted wdm coupler for optical amplifiers and methods for using 3-dimensional inscripted wdm couplers in networks
US20220404555A1 (en) * 2021-06-22 2022-12-22 Corning Research & Development Corporation Optical assembly for coupling with two-dimensionally arrayed waveguides and associated methods

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