JP2017116673A - Optical signal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical signal processor capable of simply positioning cores of input/output end surfaces of a plurality of optical waveguide (PLC) chips by passive alignment with a predetermined accuracy.SOLUTION: An optical signal processor comprises: two holding components 10 and 20 having plate surfaces faced and erected in parallel on a pedestal 30 and having a plurality of grooves 11 and 21 formed to be faced on the respective facing plate surfaces; and a plurality of optical waveguide chips 100, 100' and 100'' sandwiched in the width direction by the facing grooves 11 and 21 and laminated. The optical waveguide chips 100 and 100' and 100'' consist of a substrate 101 and an optical waveguide layer 102, and the surfaces having the optical waveguide layer 102 are laminated to be faced on the side of the pedestal 30. At least a part of the surfaces of the optical waveguide chips 100 and 100' and 100'' contacts a part of the side surfaces of the grooves 11 and 21 of the holding component 10 and 20 on the side of the pedestal 30.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an optical signal processing apparatus using a planar lightwave circuit type optical component such as a wavelength selective switch used in an optical communication network.

  As the capacity of optical communication is increased, the transmission capacity is increased by the wavelength division multiplexing (WDM) system, while the throughput of the path switching function in the node is strongly demanded.

  Conventionally, the path switching of the optical signal has been mainly performed by an electrical switch after converting the transmitted optical signal to an electrical signal, but in recent years, taking advantage of the characteristics of the optical signal that is high speed and wide bandwidth. In addition, ROADM (Reconfigurable Optical Add / Drop Multiplexer) systems that perform path switching such as add / drop using an optical switch or the like as an optical signal have been introduced.

  Specifically, in this ROADM system, an optical signal that is wavelength division multiplexed (WDM) is added (added) and dropped (dropped) at each node with a network as a ring type, and there is no need for this. Has the advantage that the node device is small in size and low in power consumption. A wavelength selective switch (WSS) module is required as an optical signal processing apparatus / device required for future development of these ROADM systems.

  Conventionally, as such a wavelength selective switch (WSS), for example, a WSS using a MEMS (Micro Electro Mechanical Systems) mirror array in a spatial optical system connected to a planar lightwave circuit system is known (for example, Patent Document 1). reference).

  FIG. 1 shows the configuration of a WSS using a MEMS mirror array as an example of such a conventional optical signal processing apparatus. FIG. 1A is a plan view of an intermediate-layer substrate 800 of WSS in which a planar lightwave circuit system in which a plurality of planar lightwave circuit substrates 800 and 800 ′ are stacked and a spatial optical system including a MEMS mirror array 840 are connected. FIG. 1B is a side view thereof.

  In the WSS shown in FIG. 1, an optical signal (wavelength λ 1) that is wavelength division multiplexed (WDM) in the Z direction from the input side optical fiber in the center of the left end of FIG. 1 to the input port of the substrate 800 of the planar lightwave circuit system. , Λ2,... Λ5) are input as input signals. The input signal is demultiplexed for each channel optical signal having a different wavelength by one central wavelength demultiplexer configured on the substrate 800 and output from the right end of the substrate 800.

  The wavelength demultiplexer is, for example, an arrayed waveguide diffraction grating made of an optical waveguide (PLC: Planar Lightwave Circuit) having a quartz glass-based slab waveguide 801 and an arrayed waveguide 802 on a substrate 800. (AWG: Arrayed Waveguide Grating).

  Since such an AWG is composed of only passive elements, the traveling direction of the optical signal is reversible, and the WDM optical signal input from the slab waveguide 801 side is demultiplexed for each wavelength from the array waveguide 802 side, and + Z In addition to outputting in the direction, it is also possible to output the optical signal of each wavelength input from the arrayed waveguide 802 side in the −Z direction as a WDM optical signal combined from the slab waveguide 801 side.

  The demultiplexed channel optical signal is emitted from the center of the right end of the substrate 800, which is the PLC chip, and constitutes the MEMS mirror array at the right end of FIG. 1 by the lenses (the cylindrical lens 810 and the main lens 830) in the spatial optical system. The light is focused on the MEMS mirror 840. Here, the MEMS mirror array is arranged so that the optical signals of the respective wavelength channels are input to the respective mirrors 840.

  Therefore, by adjusting the angle of each MEMS mirror 840, the optical signal of each wavelength channel can be reflected in a different direction. For example, in the WSS shown in FIG. 1A, the mirror is swung in the in-plane direction (± X direction) of the substrate 800 with respect to the optical axis Z, so that the other AWG on the same substrate 800 is reversed (−Z Direction).

  In addition, as shown in the side view of FIG. 1B, the WSS of this conventional example is arranged above and below the central arrayed waveguide grating substrate 800 (PLC chip) including the input port in the planar lightwave circuit system portion. A multi-stage WSS in which a plurality of arrayed waveguide grating substrates 800 ′ (PLC chips) having only a plurality of output ports are stacked.

  Therefore, the angle of each MEMS mirror 840 is reflected so as to reflect in the vertical direction (± Y direction) of the substrate surface with respect to the optical axis Z, and further adjusted, so that the AWG of another stacked PLC chip 800 ′ can be adjusted. It is also possible to input an optical signal in the reverse direction (−Z direction).

  In the WSS shown in FIG. 1, the optical signals (wavelengths λ1, λ2,..., Λ5) of each wavelength channel reflected and input again to the AWG again are multiplexed by the AWGs connected to the output ports. 1 The WDM signal is output again from the leftmost output port in the -Z direction.

  For example, in FIG. 1, since five AWGs are provided on one PLC chip, if four output side array waveguide gratings are arranged with respect to one input side array waveguide grating, The PLC chip 800 alone functions as a WSS with 1 input and 4 outputs (1 × 4), and the same PLC chip 800 ′ with only an output port is stacked on top and bottom, for a total of 5 sheets, and as a whole A 1 × 24 WSS can be configured.

  Here, each wavelength light is demultiplexed by the arrayed waveguide grating (AWG) provided on the PLC circuit board (PLC chip), but the fiber array is arranged in multiple stages without using the AWG, or A WSS or the like in which a beam is simply output by a PLC chip and a diffraction grating is provided on the spatial optical system side to demultiplex a wavelength is also generally known.

JP 2005-526287 A

  However, in the WSS in which a plurality of PLC chips as shown in FIG. 1 are stacked, conventionally, a spatial optical system is used for a plurality of PLC chips of a planar lightwave circuit system when positioning between the planar lightwave circuit system and the spatial optical system. It is necessary to adjust the position of the PLC chip, etc. while monitoring the position of the light beam of the incident / outgoing light or the position of the PLC chip, and to perform precise alignment such as active alignment. There was a problem of not going up.

  Particularly, the alignment in the vertical direction of the PLC chip, that is, the Y-axis direction in FIG. This is because the beam diameter output from the PLC chip is about several μm in the Y-axis direction, but in the coupling portion of the optical core of the input / output unit of the PLC chip, it is a sub-multiple of 1/10. This is because alignment accuracy of about a micron is required.

  The PLC chip has a width of several centimeters in the X-axis direction, and the position, interval, etc. in the PLC chip of individual cores for inputting and outputting optical signals can be accurately determined by lithography. The position in the X direction as a whole needs to be aligned with submicron accuracy in the same manner as in the Y direction over the entire area.

  Further, in the Z-axis direction, which is the optical axis, depending on the design of the spatial optical system, the margin is slightly wider than the X-axis and Y-axis and may be several μm to several tens of μm, but alignment is still necessary. .

  Also, the direction and direction defined by the direction of the PLC chip that defines the emission and incidence direction of the light beam with respect to the spatial optical system, for example, the rotation directions (θx, θy, θz) around the X, Y, and Z axes. However, an alignment accuracy of about several tens of millimeters in angle is required.

  Furthermore, when a lens or the like is shared by a plurality of PLC chips, the distance in the X and Y axis directions between the core of the optical waveguide and the PLC chip is as close as possible to the optical axis (Z axis) of the lens or the like. Need to be placed. However, in order to actively align a plurality of adjacent PLC chips, it is difficult or very complicated to realize the aligning device from the viewpoint of interference of gripping parts of the PLC chip and the movable range of the device for aligning. There is a problem that a special mechanism is required.

  Accordingly, the present invention has been made in view of such problems, and an object of the present invention is to provide a structure of an optical signal processing apparatus that precisely stacks a plurality of PLC chips (planar lightwave circuit boards) including optical waveguides. In particular, when the number of PLCs is three or more, the position of the waveguide core of each PLC chip can be easily and precisely aligned (aligned) on each axis or a plurality of axes at a time so that it can be mounted. It is to provide a signal processing apparatus.

  In order to achieve such an object, the present invention is characterized by having the following configuration.

(Structure 1 of the invention)
Two holding parts erected on the pedestal with the plate surfaces facing each other in parallel,
A holding part having a plurality of grooves formed to face each other on each opposing plate surface;
An optical signal processing device having a plurality of optical waveguide chips laminated with both ends in the width direction being sandwiched by the facing grooves,
The optical waveguide chip comprises a substrate and an optical waveguide layer, and is laminated with the surface on which the optical waveguide layer is formed facing the pedestal side,
At least a part of the surface of the optical waveguide chip is in contact with a part of the side surface on the pedestal side of the groove of the holding component.

(Configuration 2)
The optical waveguide layer of the optical waveguide chip is removed at a width smaller than the depth of the groove of the holding component at both ends in the width direction of the optical waveguide chip,
A part of the surface of the substrate from which the optical waveguide layer of the optical waveguide chip is removed is in contact with a part of the side surface on the pedestal side of the groove of the holding component. Optical signal processing device.

(Structure 3 of the invention)
The invention is characterized in that a side surface of the optical waveguide layer in contact with a portion of the optical waveguide chip from which the optical waveguide layer is removed and a part of the opposing plate surface adjacent to the groove of the holding component are further in contact with each other. The optical signal processing apparatus according to Configuration 2.

(Configuration 4)
4. The optical signal processing apparatus according to Configuration 3, wherein one holding component is fixed to the pedestal, and the other holding component can be moved parallel to the pedestal surface by pressing.

(Structure 5 of the invention)
Structure 3 of the invention characterized in that both holding parts are fixed to a pedestal and the optical waveguide chip can be pressed by a pressing part through a through hole provided in the bottom of the groove of one holding part. Optical signal processing device.

(Structure 6 of the invention)
In the plurality of optical waveguide chips, one or more through holes penetrating the substrate and the optical waveguide layer are formed at the same position, and columnar components are fixed through the through holes. An optical signal processing apparatus according to Configuration 1 of the invention.

(Configuration 7)
The optical signal processing device according to any one of configurations 1 to 6, wherein the plurality of grooves formed in the holding component are all parallel in a direction along the groove.

(Configuration 8)
The optical signal processing apparatus according to any one of configurations 1 to 6, wherein the plurality of grooves formed in the holding part all have extended lines in a direction along the groove at one point.

  The present invention integrates a plurality of PLC chips that are simply and accurately mounted by passive alignment that does not require active adjustment at least in the Y-axis direction with respect to the cores of the input / output end faces of the plurality of PLC chips. It is possible to provide an optical signal processing device. In particular, three or more PLC chips can be stacked and passively mounted with high accuracy and high density.

It is the top view and side view which show the structure of WSS using the MEMS mirror array which is the conventional optical signal processing apparatus. 1 is a front view of an optical signal processing device according to a first embodiment of the present invention. 1 is a perspective view of an optical signal processing device according to a first embodiment of the present invention. FIG. 3 is a perspective view of a single holding component according to the first embodiment of the present invention. It is sectional drawing explaining the simple laminated structure of the PLC chip shown as a comparative example. It is a perspective view which shows a part of mounting process of Embodiment 1 of this invention. It is a perspective view of the other example which shows a part of mounting process of Embodiment 1 of this invention. In the mounting process of Embodiment 1 of this invention, it is the front view to which the junction part of the groove | channel of a holding component and a PLC chip was expanded. In the mounting process of Embodiment 1 of this invention, it is a front view which shows the example which formed the antireflection film and the reinforcement board in the light input / output end surface to the space side. In Embodiment 1 of this invention, it is YZ sectional drawing in the groove | channel of the holding | maintenance component of the optical signal processing apparatus which laminated | stacked the several PLC chip | tip. In other examples of Embodiment 1 of the present invention, it is a YZ sectional view in a slot of holding parts of an optical signal processing device which laminated a plurality of PLC chips. In other examples of Embodiment 1 of the present invention, it is a YZ sectional view in a slot of holding parts of an optical signal processing device which laminated a plurality of PLC chips. It is XY sectional drawing of the PLC chip which concerns on the 2nd Embodiment of this invention. It is a front view of the optical signal processing apparatus which concerns on the 2nd Embodiment of this invention. It is a fragmentary perspective view of the optical signal processing apparatus which concerns on the 2nd Embodiment of this invention. It is a front view which shows the example of the mounting process of the optical signal processing apparatus of Embodiment 2 of this invention. It is a front view which shows the other example of the mounting process of the optical signal processing apparatus of Embodiment 2 of this invention. It is a front view which shows the example of mounting of the optical signal processing apparatus of Embodiment 3 of this invention. It is a figure which shows the example which calculated the relationship between the thickness of the board | substrate of the PLC chip | tip of the optical signal processing apparatus of Embodiment 3 of this invention, and bending amount. It is a perspective view of the PLC chip | tip of the optical signal processing apparatus of Embodiment 4 of this invention. It is a perspective view of the mounting example of the optical signal processing apparatus of Embodiment 4 of this invention.

  In the embodiment of the present invention, a planar lightwave circuit (PLC) of a glass thin film formed on a silicon (Si) substrate will be described as an example of a PLC chip constituting an optical signal processing device. The structure is not limited to this as long as the structure has an optical circuit such as a waveguide and is an integrated structure. For example, as a substrate or a waveguide, in addition to quartz glass, an organic polymer, a semiconductor such as Si or indium phosphide (InP), a compound semiconductor waveguide, or a dielectric such as lithium nitride (LN) may be used. .

  In addition, a core and a clad are formed on the optical waveguide layer of the PLC, and various circuits for processing signals are mounted. Of course, from the problem to be solved by the present invention, the embodiment of the present invention Does not depend on the circuit configuration or circuit function of the PLC. In addition, an appropriate optical circuit is formed on the PLC so as to avoid a portion that contacts the groove of the holding component. However, as described above, it is not based on the circuit configuration, and is omitted in the following drawings for the sake of simplicity of explanation. doing.

  Hereinafter, embodiments of the present invention will be described in detail.

(First embodiment)
2 and 3 show an optical signal processing apparatus according to the first embodiment of the present invention.

  In the first embodiment of the present invention, an optical signal processing apparatus sandwiches a plurality of optical waveguide (PLC) chips of the same shape and size with a rectangular plate shape on a pedestal by two holding parts having grooves for holding the PLC chip. FIG. 2 shows a front view as seen from the Z-axis direction (space optical system side) of the PLC chip, and FIG. 3 shows a perspective view.

  As shown in FIG. 2, the uppermost PLC chip 100 described as a representative example has an optical waveguide layer 102 made of thin film glass deposited on a rectangular Si substrate 101. When mounted as the optical signal processing device of the present invention, all the PLC chips are installed in such a direction that the surface on which the optical waveguide layer 102 is formed is below the Si substrate 101 (on the pedestal 30 side).

  The optical waveguide layer 102 of the PLC chip 100 is formed with a core 103 that is a center for propagation and input / output of an optical signal, and a cladding around the core 103. As described above, light is emitted from the end surface on the side of the spatial optical system of the PLC chip. The alignment in the XY plane direction of the core 103 through which signals are input / output is particularly important.

  The PLC chip 100 is sandwiched between two rectangular parallelepiped or plate-shaped holding parts 10 and 20 that are erected on both sides of the upper surface of the pedestal 30 so as to face each other, and is formed on the opposing surface of each holding part. The both ends of the chip in the width direction are sandwiched by the grooves 11 and 21 and are stacked and mounted.

  In the description and drawings, the PLC chip 100 and the corresponding grooves 11 and 21 will be described as representative, but a plurality of other PLC chips 100 ′,..., 100 ″ are basically the same as the PLC 100. The same holds true for the shape and size of the two holding parts 10 and 20, and the corresponding grooves 11 ′,..., 11 ″ and grooves 21 ′,.

  The groove widths of the two grooves 11 and 21 are formed larger than the entire chip thickness including the substrate 101 and the optical waveguide layer 102 of the PLC chip 100. As shown in FIG. 3, these grooves are formed along the longitudinal direction (Z-axis direction) and a plurality of grooves are formed in the Y-axis direction. The plurality of PLC chips are arranged in the width direction (X direction). Both end portions of the optical signal processing device are held by the opposing grooves of the two holding components facing each other along the longitudinal direction, and are stacked and mounted to constitute an optical signal processing device.

  The optical fiber array 300 that can be seen in the PLC chip depth direction (Z-axis direction depth side) of the optical signal processing device of FIG. 3 has a plurality of optical fibers that input and output optical signals to the input / output ports of the optical signal processing device. It is bundled in a shape.

(Holding parts)
FIG. 4 shows a perspective view of a single piece of the holding component 10 having the groove 11. The holding component 10 is formed of a rectangular parallelepiped or a plate-like glass substrate, and a plurality of grooves 11, 11 ′,..., 11 ″ are formed in a predetermined pattern on the plate surface by photolithography and etching. The groove width, groove depth, and groove spacing are precisely controlled with lithography accuracy. The holding component 20 facing the grooved surface has the same configuration.

  Here, an example is shown in which the holding component is formed from a glass substrate by photolithography, but precision machining may be used as long as it is a means for forming a similar highly accurate groove. Moreover, although the example of the glass substrate was shown as the material of the holding component, a substrate such as a semiconductor such as Si, a polymer, or a metal may be used.

  As described above, various materials can be used as the material of the PLC chip. Preferably, the optical waveguide layer 102 is made of quartz glass and the substrate 101 is made of silicon (Si). Excellent in terms of long-term stability. Considering this point, it is preferable to use a material having a thermal expansion coefficient close to that of the PLC chip substrate 101, for example, Tempax glass manufactured by Corning, as the glass substrate of the holding component. When using a metal, it is preferable to use Kovar having a thermal expansion coefficient close to that of the substrate 101.

  The shape of the groove of the holding component is preferably a rectangular shape as shown in FIG. 4, but is not limited to this as long as the PLC chip can be mounted. However, the groove side surface 11a on the side that becomes the pedestal side when standing is required to be precisely positioned at right angles to the plate surface of the holding component. The holding component 10 and the holding component 20 can be duplicated as a substrate having the same pattern by cutting out from a large substrate on which grooves having the same pattern as in FIG. 4 are formed, and the groove width, groove shape, The arrangement of the grooves is almost the same shape.

  As shown in FIG. 2 and FIG. 3, the grooved plate surfaces of the holding component 10 and the holding component 20 are opposed to both sides in the X direction on the upper surface of the pedestal 30, and the depth direction of the groove (the X axis in FIG. 2). Direction) and the thickness direction of the PLC chip 100 (Y-axis direction in FIG. 2) are arranged upright and have a role of supporting the PLC chip 100 with both ends sandwiched by the grooves 11 and 21. It is At this time, since the surface on the side of the optical waveguide layer 102 of the PLC chip 100 is disposed downward, a part of the groove side surfaces 11a and 21a on the lower side (the pedestal 30 side) of each of the groove 11 and the groove 21 A part of the surface of the optical waveguide layer 102 of the PLC chip 100 is in contact.

  In general, since the thickness of the optical waveguide layer 102 can be formed more accurately than the thickness of the bulk substrate 101, in this embodiment, the arrangement of the input / output cores of each PLC chip is Y In the axial direction, it is precisely positioned by the position of the groove of the holding component and the thickness of the optical waveguide layer of the PLC chip, and there is an effect that active alignment in the Y-axis direction becomes unnecessary.

  Conventionally, it has been necessary to hold each PLC chip and perform active alignment so that it is in an appropriate position, and to fix and position it in the Y-axis direction. It is possible to perform direction positioning.

(Contrast with comparative example)
Further, as a comparative example, a method of directly mounting a plurality of PLC chips without using holding parts, or simply stacking and arranging them via a spacer, an adhesive 501 or the like, as in a simple stacked structure of PLC chips shown in FIG. Is also possible. However, in the case of this comparative example, the distance between the cores in the Y-axis direction affects the thickness accuracy of the entire chip including the substrate 101 in addition to the mounting accuracy of the joint portion. It is necessary to control with high accuracy.

  Furthermore, especially in the case of three or more PLC chips, if the stacking is simply performed as in the comparative example, an error in the distance between the cores in the Y-axis direction is accumulated based on the first PLC chip 100. Will do. That is, the second, the third,..., The (n−1) th mounting error are all accumulated in the error in the inter-core distance between the first PLC chip and the nth PLC chip in the Y direction. It will be done.

  By using the configuration of the present invention, it is only necessary to consider the distance from the surface of the optical waveguide layer 102 to the core position in the optical waveguide layer 102 without considering the thickness of the entire PLC chip including the substrate 101 of the PLC chip. The first effect is obtained.

  In general, the optical waveguide layer 102 is laminated with high accuracy, and the thickness can be controlled with higher accuracy than the thickness of the substrate. At this time, the relative positional error of the plurality of grooves 11, 11 ′,..., 11 ″ and the error of the groove width also have an influence, but in the present invention, the holding component is also formed by lithography. Since these errors are determined by lithography accuracy, they can be made small enough to be ignored.

  Further, by using the configuration of the present invention, the distance between the cores in the Y-axis direction is determined by the individual groove position, groove width, and optical waveguide layer thickness. As compared with the configuration of the comparative example, the second effect that the error does not accumulate is also obtained.

  Therefore, even when a large number of three or more PLC chips, for example, 20 chips are stacked, it is only necessary to consider the individual groove and the thickness of the optical waveguide layer of the chip, and these can be controlled with very high accuracy. With respect to the distance between the cores in the Y-axis direction of all the PLC chips, an optical signal processing device fixed with high accuracy can be easily provided by passive mounting.

  In addition, the mounting accuracy of the angle θz in the rotation direction around the optical axis (Z axis) is also determined only by the positional relationship between the grooves of the two holding parts, so that the holding parts originally formed with the same high-precision pattern grooves By correctly standing and fixing on the plane of the pedestal 30 using 10 and 20, it is possible to mount the chip while minimizing the relative θz error between the plurality of chips.

  The above is the effect of the first embodiment of the present invention. Next, the mounting method of the present invention will be described.

(Mounting process of Embodiment 1)
6 to 12 show examples of the mounting process according to the first embodiment of the present invention.

  As shown in FIG. 6, the holding components 10 and 20 are bonded and fixed with adhesives 601 and 602 so that the opposing plate surfaces are parallel and stand vertically on a pedestal 30 made of glass or the like.

  When the holding parts 10 and 20 are thin and difficult to stand on their own, as shown in FIG. 6, the reinforcing plates 610 and 620 are separately used as needed to stand and be almost perpendicular to the base. It may be fixed. At this time, the distance between the opposing plate surfaces of the two holding parts 10 and 20 facing each other is set to be slightly smaller than the length and width in the X-axis direction of the PLC chip stacked between them, and the depth of the groove The distance between the bottom surfaces of the opposing grooves of the two holding parts to which is added is set to be slightly larger than the width of the PLC chip, and are arranged in parallel.

  For the parallel arrangement of the holding parts, as shown in FIG. 7, a spacer part 700 or the like is used as appropriate, or two notches (grooves) 701 and 702 parallel to the longitudinal direction of the Z-axis are formed on the base 30 as necessary. It may be provided.

  Thereafter, as shown in FIG. 8, each of the PLC chips 100 and the like are individually inserted with the surface on the optical waveguide layer 102 side facing the pedestal 30 side (lower side). At this time, due to the weight of the PLC chip 100, a part of the surface of the optical waveguide layer 102 is in contact with the groove side surfaces 11a and 21a on the lower side (pedestal side) of the grooves 11 and 21 of the holding components 10 and 20, respectively. Become.

  Thereafter, in a state where the light input / output end faces (XY planes on the front side in the Z direction) of the plurality of PLC chips coincide with each other in a state of abutting against a flat plate or the like on the front side in the Z direction, Adhesives 808 and 809 are permeated between the PLC chips.

  Further, the core position in the X-axis direction is adjusted to an optimum position as active alignment by image observation or the like, and then the adhesive is cured and fixed.

  FIG. 8 shows an enlarged front view of the joint between the part of the grooves 11 and 21 of the holding components 10 and 20 and the PLC chip 100 as seen from the Z-axis direction. As described above, the adhesive portion is filled with adhesives 808 and 809 between the side surface of the PLC chip and the bottom surface of the groove, and penetrates in the longitudinal direction of the Z-axis. Moreover, in order to strengthen the adhesive strength, an adhesive may be used as appropriate in the outer peripheral portion or the PLC chip gap portion other than the groove portion.

  Thereafter, a plurality of chips can be subjected to a lapping process on the light input / output end face (XY plane on the front side in the Z direction) of the PLC chip that inputs and outputs the beam light to the space side, if necessary. Thereby, it is possible to further improve the relative positional accuracy in the Z direction of the light input / output end faces of the plurality of PLC chips.

  As shown in FIG. 9, when a beam is directly input / output from the core to the air, a thin glass plate 900 formed with an antireflection film is appropriately attached to the light input / output end face to the space side. It is possible to prevent the generated Fresnel reflection.

  Also, as a reinforcement of the adhesive strength, as shown in FIG. 9, a plurality of chips and holding parts are connected with reinforcing plates 901 and 902 such as a common glass plate at a position where there is no core on the input / output end face. You may reinforce suitably by adhesion fixation.

(Connection with optical fiber array)
As shown in FIG. 3 described above, the PLC chip and the optical fiber array 300 are optically connected to the PLC chip on the side opposite to the depth direction in the Z-axis direction, in addition to the end face for obtaining light to the space side. It has an input / output terminal and a port. This is realized by bonding and fixing an optical fiber array 300 or the like in which optical fibers are integrated to each PLC chip in the same manner as a normal PLC chip component.

  The chips can be mounted on the holding component in advance in a state where each optical fiber array and each PLC chip are integrated. Alternatively, the optical fiber array may be bonded and fixed to each PLC chip after being mounted on the holding component.

  In that case, the optical fiber arrays are appropriately arranged so that the optical fiber arrays connected to the respective PLC chips do not interfere with each other. As a means for avoiding interference, there is a method of providing a cutout in the PLC chip.

  Alternatively, the end face to which the optical fiber array of the PLC chip is connected is not limited to the same plane as long as it does not interfere with the holding component. That is, the length of the holding component in the Z-axis direction is set to be shorter than the length of the PLC chip in the Z-axis direction, and the end face (side surface, YZ plane) of the PLC chip in the X-axis direction is exposed. Two or more fiber array connection end faces may be provided for the PLC chip, and two of them may be arranged in the direction of the end face (side face) opposite to the PLC chip. Alternatively, the optical fiber array itself may be created in a state where a plurality of optical fibers are two-dimensionally arranged, and may be connected to a plurality of PLC chips in a lump.

  With the above procedure, the configuration of the present embodiment can be mounted and manufactured, and a switch function or the like by combining with the MEMS switch as used in FIG. 1 can be realized.

(PLC chip direction)
In the present embodiment, the substrate surfaces of all the PLC chips are arranged substantially in parallel, that is, the relative angle Δθz of the angle direction θz around the Z-axis of the substrate surface of each PLC chip is substantially 0. It is also possible to set each Δθz to an arbitrary angle other than 0 by arranging the holding parts 10 and 20 so as to be in different groove positions from different parts without cutting out from the same substrate. The same applies to the following embodiments.

  The rotation angle direction θx around the X axis of the plurality of PLC chips can be arbitrarily determined depending on the pattern of the grooves 11 and 21 on the holding component. For example, as shown in FIG. 4, the relative angle of θx of each chip can be set to zero by forming the grooves 11, the grooves 11 ′, and the grooves 11 ″ in parallel.

  FIG. 10 shows a YZ cross-sectional view (side surface) perpendicular to the X axis in the groove portion of the holding component of the optical signal processing device when a plurality of PLC chips are stacked and arranged. As shown in the figure, (1) the light input / output end faces to the space of each PLC chip are aligned or parallel to each other, and (2) the inclination θx (rotation angle around the X axis) of the PLC chip substrate surface By setting the relative angle to zero, the light beams input and output from all the PLC chips can be made parallel.

  In this case, it is noted that the directions along the grooves of the holding parts are all parallel, and that the angle formed between the light input / output end face to the space of the PLC chip and the substrate surface of the PLC chip is not necessarily a right angle. I want to be.

  On the other hand, as shown in FIG. 11, (1) the input / output end faces of each PLC chip are formed at different angles including a right angle other than a right angle with respect to the substrate surface by each PLC chip. It is possible to output the beam from the chip at an arbitrary relative angle with respect to the rotation angle direction θx around the X axis.

Similarly, as shown in FIG. 12, (2) if the groove direction of the holding component is formed in advance so that the relative angle of θx falls within a predetermined range, each PLC chip is arranged around the X axis. It is possible to output the beam at an arbitrary relative angle with respect to the rotation angle direction θx.
In particular, as shown in FIG. 12, at the left end on the space side, the direction of the groove is arranged so that each beam is focused at one point, that is, the extension lines in the direction along the groove all intersect at one point. Thus, various advantages in the optical layout of the spatial optical system can be obtained, for example, the spatial optical system can be reduced in size by reducing the effective focal length. In addition, the figure shows an example in which the end surfaces of the respective chips and the holding parts are not flush with each other. You may align the end surface of each chip | tip and holding components.

(Second Embodiment)
FIG. 13 is an XY sectional view of a PLC (optical waveguide) chip 1300 according to the second embodiment of the present invention, and FIG. 14 is mounted with a plurality of optical waveguide chips according to the second embodiment of the present invention. FIG. 15 is a front view of a PLC chip sandwiched by the holding parts 10 and 20 having a groove and stacked and integrated, as viewed from the Z-axis direction. FIG. It is the perspective view which expanded partially.

  In the cross-sectional view of the PLC chip 1300 of the second embodiment in FIG. 13, the optical waveguide layer 102 including the core 103 is formed on the substrate 101 as in the first embodiment, but when the optical chip is mounted as an optical signal processing device. According to the direction, the optical waveguide layer 102 is described below.

  The difference between the PLC chip 1300 of the second embodiment shown in FIG. 13 and the PLC chip 100 of the first embodiment is that the PLC chip 1300 is an optical waveguide made of thin film glass at both ends in the X-axis direction (width direction) of the substrate 101. The layer 102 is removed with a predetermined width, and the substrate 101 is exposed.

  The waveguide layer removing portions 1301a and 1301b indicated by dotted lines in FIG. 13 have a width that is smaller than the depth of the groove of the holding component at both ends in the X-axis direction of the substrate 101 of the PLC chip 1300 and where there is no optical circuit pattern. The waveguide layer removal portions 1301a and 1301b are formed so as to penetrate in the chip longitudinal direction (Z-axis direction).

  By these waveguide layer removing portions 1301a and 1301b, a part of the substrate 101 of the PLC chip 1300 is exposed to form substrate exposed surfaces 1302a and 1302b, which are adjacent to the waveguide layer removing portions 1301a and 1301b. Side surfaces of the optical waveguide layer 102 to be formed form waveguide layer side surfaces 1303a and 1303b.

  As shown in the front view of FIG. 14, the holding parts 10 and 20 are made of the same parts as in the first embodiment, and are erected on the pedestal 30 with the plate surfaces having the grooves 11 and 21 facing each other in parallel. Each PLC chip 1300 is sandwiched and mounted in the opposing grooves 11 and 21 of the holding component.

  At this time, as shown in FIG. 14, since the waveguide layer side of the PLC chip 1300 is mounted below, in the Y direction, a part of the lower (pedestal side) side surfaces 11a and 21a of the grooves 11 and 21 of the holding component, Part of the substrate exposed surfaces 1302a and 1302b which are the surface of the PLC chip 1300 are in contact with each other.

  In the X direction, at least one of the side surfaces (for example, the waveguide layer side surface 1303b) adjacent to the waveguide layer removing portion of the optical waveguide layer 102 is at least one opposing plate surface (for example, the groove of the holding component) 21b) is in contact with a part.

  As shown in the front view of FIG. 14 and the partial perspective view of FIG. 15, the PLC chip 1300 having the width direction end portions accommodated and sandwiched in the opposing grooves 11 and 21 of the left and right holding parts 10 and 20 is generally X The part 21b of the opposing plate surface adjacent to the groove 21 of the right holding component 20 and the waveguide layer side surface 1303b of the PLC chip are in contact with each other, while the left holding component 10 is located. Note that there is a gap between them.

With such a structure, the following two remarkable effects can be obtained in passive mounting.
(1) As for the accuracy in the thickness direction (Y direction) of the core position of the input / output part of the PLC chip, as in the first embodiment, the error does not accumulate, the position error and width error of each groove, and the optical It is determined by the thickness error of the waveguide layer. Further, the thickness error of the optical waveguide layer is determined by the distance from the surface of the optical waveguide layer to the core position in the first embodiment, whereas in the second embodiment, the exposed substrate is exposed. It is determined by the distance from the surface of the core to the core position.

The optical waveguide layer is formed from the substrate surface in the order of the under cladding layer, the core layer, and the over cladding layer, and the thickness thereof is precisely controlled. Since the distance to the core layer is formed by the previous process, the thickness accuracy is ensured more precisely than the distance from the core layer to the surface of the over clad layer. Thereby, in the structure of the second embodiment, the positioning control in the thickness direction (Y-axis direction) of the core position is realized by passive alignment with higher accuracy than in the first embodiment.
(2) In the first embodiment, the positioning control in the X direction is active alignment. However, in the second embodiment, at least one of the side surfaces in contact with the removed portion of the optical waveguide layer of each PLC chip is at least one of them. By making contact with a part of the opposing plate surface adjacent to the groove of one holding component, all chips may be abutted against the holding component in the X-axis direction with respect to the waveguide layer side surface of the removal portion. In addition, positioning in the in-plane direction (X-axis direction) of the core position can be passively mounted without optical alignment.

  At this time, the distance from the side surface of the optical waveguide layer of the PLC chip to the core position affects the mounting accuracy in the X direction. As described above, the removal position and the removal width of the optical waveguide layer of the PLC chip are as follows. Since it is formed by photolithography, it is patterned with very high accuracy, and as a result, high mounting accuracy is realized also in the X-axis direction.

(Mounting process of Embodiment 2)
The mounting method of the second embodiment is basically realized by the same procedure as that of the first embodiment. However, in all the PLC chips, in the Y direction, the side surface below the groove of the holding component and the above-described PLC chip. It is necessary that the substrate upper surface exposed by removing the optical waveguide layer is in contact with the side surface 1303b of the optical waveguide layer and a part (21b) of the opposing plate surface adjacent to the groove of the holding component in the X direction. is there.

  For this reason, after mounting all the PLC chips in the grooves at the time of mounting, before fixing them with an adhesive or the like, the entire apparatus is temporarily tilted to, for example, about 45 ° diagonally to take advantage of the weight of the PLC chips. Can be simultaneously aligned in the XY directions by a single operation.

  Further, as shown in FIG. 16, in addition to or in addition to the positioning for tilting the entire apparatus, first, one of the holding parts is first fixed on the base (for example, the right holding part 20 is bonded). The other holding part (for example, the left holding part 10) is not fixed on the pedestal 30, but temporarily fixed as a structure that can be slid in parallel. In this state, the PLC chip is fixed. After mounting 1300 and the like, the temporarily held left holding component 10 is pressed to the right in the X-axis direction, translated on the pedestal surface and slid, and the PLC chip waveguide layer side surfaces 1303a and 1303b and the holding component 10 are mounted. , 20 can be used, such as fixing the holding component 10 and each PLC chip after pressing a portion 11b, 21b of the plate surface adjacent to the groove.

  Alternatively, as shown in FIG. 17, after the PLC chip 1300 is mounted in a state where one or both of the holding parts are fixed to the pedestal 30 with an adhesive, it is further provided, for example, at the bottom of the groove 11 of the left holding part 10. The PLC chip 1300 mounted by the pressing component 1700 is pressed to the right through the through-hole, and the waveguide layer side surface 1303b of the PLC chip and the surface 21b of the holding component 20 are in contact with each other. Then, it may be fixed with an adhesive or the like.

(Third embodiment)
FIG. 18 shows an optical signal processing apparatus on which a plurality of optical waveguide chips are mounted according to the third embodiment of the present invention. In the third embodiment, the substrate of each PLC chip is thinned, and a larger number of PLC chips 1800 than those in the first and second embodiments are sandwiched and held by holding parts 10 and 20 having left and right grooves. The optical signal processing device is configured integrally. FIG. 18 is a front view of the PLC chip viewed from the Z-axis direction.

  The PLC chip 1800 of the third embodiment has waveguide layer removal portions at both ends in the width direction, similar to the PLC chip 1300 of the second embodiment of FIG. 13, except that the substrate 101 is thin. PLC chip. A normal PLC chip substrate has a thickness of about 1 mm. However, if a large number of PLC chips are stacked according to the first and second embodiments, the thickness direction (Y The total axial length is increased.

  However, according to the configuration of the third embodiment, the thickness of the PLC chip 1800 in the substrate direction is reduced by polishing or etching, and is 0.3 mm or less. As a result, even when the number of stacked chips is increased, the thickness and height in the Y-axis direction can be suppressed, and it is possible to realize a small-sized optical signal processing device as a whole. Play.

  Further, according to the configuration of the present invention, as described above, the accuracy of the substrate thickness itself does not depend on the relative mounting position accuracy of the Y-axis of the core position. Without any problem, it can be easily reduced in thickness. However, in the third embodiment, it is necessary to consider an increase in warpage due to the thinner substrate of the PLC chip.

Generally, when a thin film is deposited on a substrate, a compressive or tensile stress is applied to each, resulting in warping. If the value of compressive (tensile) stress is σ, the thickness of the substrate is t ₁ , the thickness of the thin film is t ₂ , and the Young's modulus and Poisson's ratio of the substrate are E and ν, respectively, the radius of curvature R of the circular substrate is approximate. Can be expressed by the following formula (1): R = E × t ₁ ² / (6 × (1−ν) × σ × t ₂ ) (1)

That is, the curvature radius R is proportional to the square of the substrate thickness t _1, when the substrate thickness t ₁ is smaller curvature radius R is small, i.e., warpage becomes large. If the warpage is too large, restrictions in the spatial optical system occur, and handling becomes difficult.

  For example, FIG. 19 shows an example in which the relationship between the thickness and the amount of chip deflection (difference between the maximum height and the minimum height caused by warpage) of a substrate made of silicon with a PLC chip having a width of 20 mm is calculated by the above formula.

  According to FIG. 19, since the warp of 10 μm or more occurs when the substrate thickness is 0.1 mm or less, it is preferable that the substrate thickness in this case is 0.1 mm or more, preferably 0.3 mm or more. Since these values actually vary depending on the substrate material and stress, the substrate thickness is set to an appropriate thickness in consideration of the influence of the warp.

(Fourth embodiment)
FIG. 20 is a perspective view of a PLC (optical waveguide) chip 2000 according to the fourth embodiment of the present invention, and FIG. 21 is an optical signal processing apparatus on which a plurality of optical waveguide chips according to the fourth embodiment is mounted. It is a perspective view, and a PLC chip 2000 that is laminated and integrated is mounted by holding parts 10 and 20 having grooves.

  The PLC chip 2000 of the fourth embodiment shown in FIG. 20 is basically the same as the PLC chip 100 of the first embodiment, and is a waveguide layer removing unit (1301a, b in FIG. 13) as in the second and third embodiments. ) Is not. Instead, one or a plurality of through holes (vias) 2001 penetrating vertically from the upper surface of the substrate 101 to the lower surface of the optical waveguide layer 102 for alignment in at least the X-axis direction are provided in each PLC chip 2000, 2000 ′, One or more are formed at the same position of 2000 ″. These through holes (vias) are formed by a photolithography technique, and are formed at desired positions in a region that does not affect the optical circuit.

  As shown in FIG. 21, in the fourth embodiment, as in the first embodiment, the plurality of PLC chips 2000, 2000 ′, 2000 ″ have the waveguide layer surfaces of the grooves 11, 21 of the holding components 10, 20 as shown in FIG. The layers are arranged so as to be in contact with the side surfaces, whereby the Y-direction distances of the core positions of the optical input / output units of the PLC chip are arranged with high accuracy without accumulating errors.

  Furthermore, in the fourth embodiment, as shown in FIG. 21, columnar parts 2100 that respectively penetrate the corresponding through holes 2001 of the PLC chips 2000, 2000 ′, and 2000 ″ are inserted, and the plurality of PLC chips penetrate the columnar parts 2100. The holes 2001 are positioned in the X-axis and Z-axis directions. By adopting such a structure, the core position in the X direction and the position of the PLC end face in the Z-axis direction of the plurality of PLC chips are determined by the via arrangement, via hole accuracy, and the diameter of the cylindrical part, and not only in the Y-axis direction. In addition, it is possible to perform passive mounting with high accuracy at predetermined positions in the X-axis and Z-axis directions.

  At this time, the columnar part 2100 preferably has a certain rigidity or more, and a glass lot part or a metal lot having a diameter of 100 μm or more is used. The shape of the through hole 2001 is a circular via that is substantially the same as or slightly larger than the columnar component 2100. Preferably, about φ500 μm is desirable from the viewpoint of stability.

  The columnar component and the through hole may be at least one, but preferably three or four at the four corners of the PLC chip as shown in the figure. Of course, the shape and cross section of the through hole 2001 and the columnar component 2100 are not limited to a circle.

  With these configurations, in the fourth embodiment, passive alignment is possible in all directions of X, Y, and Z, and after alignment, the columnar component and the through hole are integrated by adhesive fixing, and a plurality of optical waveguide chips It is possible to construct an optical signal processing device by simply stacking layers with high accuracy.

  As described above, according to the present invention, the core positions of the input / output end faces on the spatial optical system side of a plurality of PLC chips are easily mounted with desired accuracy by passive alignment that does not require active adjustment at least in the Y-axis direction. It is possible to provide an optical signal processing device in which a plurality of PLC chips are integrated. In particular, three or more PLC chips can be stacked and passively mounted with high accuracy and high density.

800, 800 ′, 100, 100 ′, 100 ″, 1300, 1300 ′, 1300 ″, 1800, 2000, 2000 ′, 2000 ″ PLC chip (planar lightwave circuit board)
801 Slab waveguide 802 Array waveguide 810 Cylindrical lens 830 Main lens 840 MEMS mirror 101 Si substrate 102 Optical waveguide layer 103 Core 30 Pedestal 10, 20 Holding parts 11, 21, 11 ′, 11 ″, 21 ′, 21 ″ Groove 300 Optical fiber array 11a, 21a Groove side surface 11b, 21b Plate surfaces 501, 601, 602, 808, 809, 1601 adjacent to the groove Adhesives 610, 620, 901, 902 Reinforcement plate 700 Spacer 701, 702 Notch 900 Reflection Glass plates with protective film 1301a, 1301b Waveguide layer removal portions 1302a, 1302b Exposed surfaces 1303a, 1303b Waveguide layer side surfaces 1700 Press component 2001 Through hole (via)
2100 Columnar parts

Claims (8)

Two holding parts erected on the pedestal with the plate surfaces facing each other in parallel,
A holding part having a plurality of grooves formed to face each other on each opposing plate surface;
An optical signal processing device having a plurality of optical waveguide chips laminated with both ends in the width direction being sandwiched by the facing grooves,
The optical waveguide chip comprises a substrate and an optical waveguide layer, and is laminated with the surface on which the optical waveguide layer is formed facing the pedestal side,
At least a part of the surface of the optical waveguide chip is in contact with a part of the side surface on the pedestal side of the groove of the holding component. The optical waveguide layer of the optical waveguide chip is removed at a width smaller than the depth of the groove of the holding component at both ends in the width direction of the optical waveguide chip,
The part of the surface of the substrate of the part where the optical waveguide layer of the optical waveguide chip is removed is in contact with a part of the side surface on the pedestal side of the groove of the holding component. Optical signal processing device. The side surface of the optical waveguide layer in contact with the portion of the optical waveguide chip from which the optical waveguide layer has been removed is further in contact with a part of the opposing plate surface adjacent to the groove of the holding component. Item 3. The optical signal processing device according to Item 2.   4. The optical signal processing apparatus according to claim 3, wherein one holding component is fixed to the pedestal, and the other holding component is movable in parallel to the pedestal surface by pressing. 4. The optical waveguide chip according to claim 3, wherein both holding parts are fixed to a pedestal, and the optical waveguide chip can be pressed by a pressing part through a through hole provided in a bottom of a groove of one holding part. Optical signal processing device. In the plurality of optical waveguide chips, one or more through holes penetrating the substrate and the optical waveguide layer are formed at the same position, and columnar components are fixed through the through holes. The optical signal processing device according to claim 1. 7. The optical signal processing device according to claim 1, wherein the plurality of grooves formed in the holding part are all parallel in a direction along the groove. The optical signal processing apparatus according to any one of claims 1 to 6, wherein the plurality of grooves formed in the holding part all extend at one point in a direction along the groove.