JP2014038199A - Optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain downsizing in consideration for connection to optical fibers even in an optical module mounted with a multi-chip integrated device.SOLUTION: In an optical module accommodating in a package 111 a multi-chip integrated device constituted by planar lightwave circuits (PLC) 113a and 113b and an optical functional member 112, PLCs include an optical waveguide for connecting optical fibers 114a and 114b, and are connected to the optical functional member in the surface opposite to a waveguide surface of an optical waveguide formed on the optical functional member. Further, in both waveguide ends of the optical waveguide formed on the optical functional member 112 and waveguide ends of the optical waveguide formed on the PLCs, there are provided folded-back mechanisms for optically coupling the respective optical waveguides to each other. The optical fibers are, of the waveguide ends of the optical waveguide of the PLCs, connected to the waveguide ends in the opposite side to the waveguide ends provided with the folded-back mechanisms, and taken out from a facing surface of the package.

Description

  The present invention relates to an optical module, and more particularly to an optical module that is miniaturized in consideration of connection with an optical fiber.

  In recent years, with an increase in communication traffic, high-capacity transmission for transmitting more data per optical fiber is required in a trunk optical transmission network. As means for realizing this, a multi-level modulation technique and a digital coherent reception technique for realizing improvement of frequency utilization efficiency and long-distance transmission have attracted attention. In the multi-level modulation method, it is essential to realize a high-performance optical modulator in consideration of the phase of light.

An optical modulator is one of optical communication basic devices that converts an electric signal into a light intensity signal, and generally requires high speed, low loss, low power consumption, small size, and high reliability. Methods for realizing the optical modulator are classified into a direct modulation method and an external modulation method. In high-speed and backbone networks, the external modulation method is the mainstream in terms of high speed and long-distance transmission. In an optical modulator to which an external modulation method is applied, a dielectric material such as LiNbO ₃ (lithium niobate, hereinafter referred to as LN) using an electro-optic effect (hereinafter referred to as EO), a semiconductor material or an organic material, electroabsorption The semiconductor material etc. which used the effect are used.

  On the other hand, in a multi-level modulation type optical modulator, since it is necessary to actively use the polarization of light, it is necessary to provide a passive optical circuit for demultiplexing and multiplexing them. However, since the optical characteristics of LN and semiconductor materials are inferior to those of glass materials in terms of low loss and connectivity with optical fibers, there has been a problem in improving functions.

  As a device for realizing a passive optical circuit with low loss, a planar lightwave circuit (hereinafter referred to as PLC) in which quartz glass is deposited on a Si substrate or the like is known. A technique in which quartz PLC is combined with an optical functional member made of a dielectric material such as LN, a semiconductor material, an organic material, or the like, using the excellent optical characteristics of quartz PLC made of a quartz glass-based material has attracted attention.

  In such an optical modulator, the optical input / output unit between the quartz PLC chip and the optical functional member chip is appropriately connected and integrated. A device in which two or more chips are integrated is handled as one device (hereinafter referred to as a multi-chip integrated device), and an optical fiber that performs optical input / output with the outside is connected to the multi-chip integrated device. As a typical example of an optical modulator using a multichip integrated device, a modulator combining a quartz PLC and an LN waveguide (hereinafter referred to as a quartz-LN modulator) is known.

  Here, when a multichip integrated device is mounted on a board in a communication apparatus, it is generally accommodated in a package or case made of metal, ceramic, etc. from the viewpoint of reliability, gas barrier properties, and the like. In general, an optical fiber and a multichip integrated device are bonded and fixed by a fiber connecting part made of glass or the like. The optical fiber passes through the pipe portion of the package or case and is connected to the multichip integrated device. In many cases, a metal-coated fiber having a metal coating on an optical fiber is used to seal the pipe portion by soldering or fixing the optical fiber with an adhesive or the like.

JP-A-2-73207

N. Mekada. Et al, "Practical method of waveguide-to-fiber connection: direct preparation of waveguide endface by cutting machine and reinforcement using ruby beads," APPLIED OPTICS, pp.5096-5102, Vol. 29, No. 34, 1 December 1990

  FIG. 1 is a top view showing a configuration of a conventional quartz-LN modulator. FIG. 2 is a cross-sectional view taken along the optical waveguide of the LN modulator. In the quartz-LN modulator 10, an LN modulator 12 having quartz PLCs 13a and 13b connected to both ends is accommodated in a package 11. The optical fibers 14 a and 14 b are connected to the quartz PLCs 13 a and 13 b at the connection end faces 21 a and 21 b by the fiber connection parts 20 a and 20 b and are fixed to the pipe portions 22 a and 22 b of the package 11. The reinforcing plates 15a to 15f are glass blocks for securing a bonding area and strengthening the connection in the connection between the fiber connection component and the quartz PLC and the connection between the quartz PLC and the LN modulator.

  The LN modulator 12 has electrodes formed along the optical waveguide, and modulates the optical signal by applying an electric field to the optical waveguide through which the optical signal is transmitted. In order to sufficiently bring out the EO effect of the LN modulator, it is necessary to provide several cm of electrodes along the optical waveguide, and the length of the LN modulator 12 in the optical axis direction is inevitably about several cm or more.

  Further, the metal material used for the package 11 and the glass material, semiconductor material, etc. used for the multichip integrated device have different thermal expansion coefficients. For this reason, since the magnitude of thermal expansion of each material differs when a temperature change occurs, a new force is applied to the optical fiber itself or the member that fixes the optical fiber due to the thermal stress corresponding to the temperature change. There was a problem that the mechanical reliability deteriorated.

  Therefore, a structure has been proposed in which an optical fiber is buckled to a certain length between a connection portion with an optical device and a pipe portion to reduce a decrease in mechanical reliability due to a temperature change (for example, a patent) Reference 1). Taking FIG. 1 as an example, the optical fibers 14a and 14b are provided with extra fiber length portions 23a and 23b that are buckled to a certain length. Therefore, in addition to the length along the optical axis direction of the LN modulator 12, the package 11 needs to be provided with extra fiber length portions 23a and 23b, and further needs to be elongated. In addition, when such a long quartz-LN modulator 10 is mounted on a board in a communication apparatus, there is a problem that mounting restrictions are increased in connection with other devices.

  An object of the present invention is to provide an optical module that is miniaturized in consideration of connection with an optical fiber even if it is an optical module on which a multichip integrated device is mounted.

  In order to achieve such an object, a first aspect is an optical module in which a multichip integrated device composed of a planar lightwave circuit (PLC) and an optical functional member is housed in a package, wherein the PLC is an optical fiber. And an optical waveguide connected to the optical functional member on a surface opposite to the waveguide surface of the optical waveguide formed on the optical functional member, and guiding the optical waveguide formed on the optical functional member. A folding mechanism for optically coupling the optical waveguides is provided at the waveguide end and the waveguide end of the optical waveguide formed in the PLC, and the optical fiber is an optical waveguide of the PLC. Of the waveguide end portions, the waveguide end portion is connected to the waveguide end portion opposite to the waveguide end portion provided with the folding mechanism, and is taken out from the opposing surface of the package.

  A second aspect is an optical module in which a multichip integrated device composed of a planar lightwave circuit (PLC) and an optical functional member is housed in a package, wherein the PLC includes an optical waveguide for connecting an optical fiber, Connected to the optical functional member on the surface opposite to the waveguide surface of the optical waveguide formed on the optical functional member, and formed on the PLC and the waveguide end portion of the optical waveguide formed on the optical functional member. The optical waveguide end portion of the optical waveguide is provided with a folding mechanism that optically couples the optical waveguides, and the first PLC of the PLCs includes an optical waveguide formed on the optical functional member. An optical waveguide for connecting the optical fiber to the optical fiber is formed, and the second PLC of the PLC is formed with an optical waveguide for connecting the two optical waveguides formed on the optical functional member in a folded manner. Optical fiber, said first connected to the optical waveguide for connecting optical fibers of PLC, characterized in that it is taken from the same surface of the package.

  A third aspect is an optical module in which a multichip integrated device composed of a planar lightwave circuit (PLC) and an optical functional member is accommodated in a package, wherein the PLC is an optical waveguide for connecting a first optical fiber. A waveguide end portion of the optical waveguide formed on the optical functional member, connected to the optical functional member on a surface opposite to the waveguide surface of the optical waveguide formed on the optical functional member, and the PLC A folding mechanism for optically coupling between the optical waveguides is provided at the waveguide end of the optical waveguide formed on the optical waveguide, and the first light is provided at the end of the PLC opposite to the folding mechanism. A first connecting component for connecting a fiber is provided, and an optical waveguide formed on the optical functional member is connected to a second optical fiber at an end opposite to one end of the optical functional member. Second connection to do Comprises a component, said first and second optical fibers is equal to or taken from the same surface of the package.

  As described above, according to the present invention, the extra fiber length portion conventionally provided between the quartz PLC and the pipe portion becomes unnecessary, and the length of the package in the longitudinal direction can be shortened.

It is a top view which shows the structure of the conventional quartz-LN modulator. It is sectional drawing which shows the structure of the conventional quartz-LN modulator. It is a figure which shows the structure of the optical module concerning the 1st Embodiment of this invention. It is a figure which shows the Example of the folding | turning mechanism of an optical module. It is a figure which shows the other Example of the folding | turning mechanism of an optical module. It is a figure which shows the structure of the optical module concerning the 2nd Embodiment of this invention. It is a figure which shows the structure of the optical module concerning 3rd, 4th embodiment of this invention. It is a figure which shows the structure of the optical module concerning the 5th Embodiment of this invention. It is a figure for demonstrating the method to accommodate a multichip integrated device in a package.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, an optical module on which a quartz-LN modulator is mounted will be described as an example. However, an optical functional member in which a planar lightwave circuit (PLC) is connected to both ends or one end of the LN modulator is integrated. If it is a multichip integrated device, it will not be restricted to this.

  FIG. 3 shows the configuration of the optical module according to the first embodiment of the present invention. The quartz-LN modulator 110 is a multichip integrated device in which an LN modulator 112 connected with quartz PLCs 113 a and 113 b is integrated, and is accommodated in a package 111. The quartz PLCs 113a and 113b are connected to the surface (lower surface) opposite to the waveguide surface (upper surface) of the optical waveguide formed in the LN modulator 112 in the vicinity of both ends of the LN modulator 112. Compared with the conventional configuration shown in FIG. 2, the quartz PLC connected to the LN modulator is connected so as to be folded into the lower surface at the end of the LN modulator.

  Each of the quartz PLCs 113a and 113b and the waveguide end portions of the LN modulator 112 is provided with a folding mechanism, and an optical waveguide formed in the LN modulator 112 and an optical waveguide formed in the quartz PLCs 113a and 113b. , Optically coupled. The optical waveguides formed in the quartz PLCs 113a and 113b are connected to the optical fibers 114a and 114b via the fiber connection parts 120a and 120b at the waveguide end opposite to the waveguide end provided with the folding mechanism. The

  The optical fiber 114a is fixed to a fiber connection part 120b that is a connection part to the quartz PLC 113b and a remote pipe part 122a facing the optical fiber 114a, and the optical fiber 114b is connected to the fiber connection part 120a and a remote pipe part opposing the It is fixed to 122b. As a result, the optical fibers 114 a and 114 b are taken out from the respective surfaces facing each other in the longitudinal direction of the package 111.

  Conventionally, in a quartz PLC, the connection surface of the quartz-LN modulator and the connection surface of the fiber connection component are separate surfaces (existing at both ends of the PLC). In the first embodiment, in the space formed by the quartz PLC connected to the lower surface of the LN modulator, by connecting the fiber connection component to the quartz PLC, the following significant effects can be obtained.

  (1) By using a folding mechanism described later, an extra fiber length portion conventionally provided between the quartz PLC and the pipe portion becomes unnecessary, and the quartz PLC that is connected on the same plane as the LN modulator is Since it is installed on the lower surface of the LN modulator, the length of the package can be shortened. For example, in one embodiment, a package of about 140 mm can be shortened to about 100 mm.

  (2) Conventionally, in order to reduce the size of the fiber connecting component as much as possible, the optical fiber is connected by a small fiber connecting component integrated with a small capillary (for example, Patent Document 1). Non-Patent Document 1). According to the first embodiment, since the length of the fiber connecting component does not affect the length of the package, it is not necessary to connect with a small component. Further, in order to connect with small parts, complicated design and mounting work for ensuring reliability are required. However, according to the first embodiment, there is no need, and reliability is maintained. be able to.

  (3) Within the package 111, the distance between the two connection points for fixing the optical fibers 114a and 114b inevitably increases, and the amount of buckling of the optical fiber is reduced or the bending radius of buckling is increased. can do. In this way, the surplus length can be sufficiently ensured, so that it is easy to ensure mechanical reliability due to thermal fluctuation.

  (4) As a method of attaching the optical fiber connecting component toward the inner side of the package, for example, it is conceivable to arrange two of the LN modulator and the optical fiber connecting component on the same plane of the quartz PLC. In this method, the width of the connection plane in the quartz PLC needs to be increased accordingly. However, according to the first embodiment, since the quartz PLC is installed on the lower side of the LN modulator with a three-dimensional configuration, it is not necessary to increase the width of the quartz PLC. This is because if the lateral width of the LN modulator is made narrower than the current width, the width of the quartz PLC can also be easily narrowed due to its excellent workability. Further, shortening can be achieved.

  (5) Conventionally, in the connection between the quartz PLC and the LN modulator, a reinforcing material made of a glass block has been provided in order to secure a bonding area and strengthen the connection. According to the first embodiment, the connection between the quartz PLC and the LN modulator has a sufficient adhesion area as shown in FIG.

  As shown in the first embodiment, when an LN modulator is used as an optical functional member, the package is shortened, but the function is not inferior, and a modulation function equivalent to that of a conventional package size is provided. It has been confirmed that a multichip integrated device having the above can be realized. That is, it was confirmed that optical waveguide characteristics such as optical loss and extinction ratio comparable to those of the conventional package size can be realized as well as the modulation function.

In this embodiment, even if an LT modulator made of a dielectric material other than LN, for example, LiTaO ₃ (hereinafter referred to as “LT”) is used as the optical functional member, the same shortening and modulation function can be realized. Can do. Furthermore, even if a GaN modulator made of GaN, which is a semiconductor material, and an InP modulator made of InP are used, the same effect can be obtained while utilizing their high EO efficiency, and an organic EO material is used. However, an equivalent effect can be obtained without reducing the advantage of the high-speed response.

  The optical functional member is not limited to the modulation function shown in the first embodiment, and for example, an EO switch waveguide, an optical-optical switch waveguide made of an organic material or a semiconductor material, or a thermo-optic switch waveguide made of Si is used. You can also. Even in these cases, it is possible to shorten the package in the longitudinal direction while maintaining the optical switch function.

  FIG. 4 shows an embodiment of the optical module folding mechanism. FIG. 4A is a first example, and is an enlarged view of the right end portion of the LN modulator 112 of the optical module shown in the first embodiment. The end face of the LN modulator 112 and the end face of the quartz PLC 113b are each ground and optically polished at an angle of 45 degrees. That is, the end surfaces 133 and 134 form a 45 degree mirror. Thereby, the optical waveguide 131 formed in the LN modulator 112 and the optical waveguide 132 formed in the quartz PLC 113b are optically coupled. In addition, in order to improve the reflectance of a 45 degree | times mirror, a metal film can also be vapor-deposited on the end surfaces 133,134.

  FIG. 4B shows a folding mechanism according to the second embodiment. V-grooves 233 and 234 having slopes of 45 degrees are formed at the end of the LN modulator 212 and the end of the quartz PLC 213, respectively. A 45-degree mirror is formed by the inclined surfaces of the V grooves 233 and 234, and the optical waveguide 231 formed in the LN modulator 212 and the optical waveguide 232 formed in the quartz PLC 213 are optically coupled. Similarly to the first embodiment, a metal film can be deposited on the V grooves 233 and 234.

  FIG. 4C shows a folding mechanism according to the third embodiment. A glass block 335 having a 45-degree inclined surface on which a metal film is deposited is fixed at a position facing the end of the LN modulator 312 and the end of the quartz PLC 313. The slope of the glass block 335 forms a 45-degree mirror, and optically couples the optical waveguide 331 formed in the LN modulator 312 and the optical waveguide 332 formed in the quartz PLC 313.

  FIG. 5 is a view showing another embodiment of the folding mechanism of the optical module. FIG. 5A shows an example in which a condenser lens 135 is further formed on the quartz PLC 113b in the first embodiment shown in FIG. 4A. As the distance between the waveguide end face of the quartz PLC and the waveguide end face of the LN modulator increases, the beam emitted from the optical waveguide spreads, and the optical coupling characteristics with the incident-side optical waveguide deteriorate. Therefore, a condensing lens is provided to condense the beam on the end face of the optical waveguide on the incident side to improve the coupling characteristics. In addition to the condenser lens, a lens for mode field diameter conversion can be formed, or an optical filter can be inserted.

  FIG. 5B is an example in which a part of the upper surface of the quartz PLC 113b and the surface in contact with the LN modulator 112 is cut in the first embodiment shown in FIG. 4A. In this embodiment, the area of the connecting portion between the LN modulator 112 and the quartz PLC 113b is made smaller than that in the first embodiment, to the extent that the reinforcing material for bonding them is not necessary. Since the difference in thermal expansion coefficient between LN and quartz glass-based material is large, stress concentrates on the connection between LN modulator 112 and quartz PLC 113b as the shape changes due to temperature change. Therefore, by reducing the area of the connecting portion, it is possible to suppress distortion and breakage associated with the shape change.

  FIG. 6 shows a configuration of an optical module according to the second embodiment of the present invention. The quartz-LN modulator 410 is a multichip integrated device in which an LN modulator 412 connected with quartz PLCs 413 and 416 is integrated, and is accommodated in a package 411. The quartz PLCs 413 and 416 are connected to the surface (lower surface) opposite to the waveguide surface (upper surface) of the optical waveguide formed in the LN modulator 412 in the vicinity of both ends of the LN modulator 412. Compared with the conventional configuration shown in FIG. 2, the quartz PLC connected to the LN modulator is connected so as to be folded into the lower surface at the end of the LN modulator.

  A folding mechanism is provided at each of the waveguide ends of the quartz PLCs 413 and 416 and the LN modulator 412, and an optical waveguide formed in the LN modulator 412 and an optical waveguide formed in the quartz PLCs 413 and 416 are provided. , Optically coupled. The optical waveguide formed in the quartz PLC 413 is connected to the optical fibers 414a and 414b via the fiber connection component 420 at the waveguide end opposite to the waveguide end provided with the folding mechanism. The quartz PLC 416 is formed with an optical waveguide for folding and connecting the two optical waveguides formed in the LN modulator 412.

  With such a configuration, the effects (1) to (5) described in the first embodiment can be achieved. In addition, since the two optical fibers 414a and 414b can be taken out from the same surface of the package 411, the mounting restrictions can be eased when the optical fiber 414a and 414b are mounted on the board in the communication apparatus.

  Furthermore, the effective working length of the optical waveguide of the LN modulator 412 for performing the modulation operation can be doubled by the folded connection using the quartz PLC 416. In addition, since the connection between the quartz PLC and the optical fiber can be made with a single fiber connection component, the manufacturing cost can be further reduced.

  FIG. 7 shows the configuration of the optical module according to the third and fourth embodiments of the present invention. In the third embodiment shown in FIG. 7 (a), the two optical fibers 514a and 514b of the optical module shown in the first embodiment are provided with the outlets facing the longitudinal direction of the package 511 ( It is provided not on the first surface) but on the side surface (second surface) in contact with the first surface. In the fourth embodiment shown in FIG. 7B, the two optical fibers 614a and 614b of the optical module shown in the second embodiment are connected to one surface in the longitudinal direction of the package 611 ( It is provided not on the first surface) but on the side surface (second surface) in contact with the first surface.

  According to this configuration, it is possible to further reduce the length of the portion of the package that corresponds to the pipe portion as compared with the first and second embodiments. Further, when mounting on a board in the communication apparatus, the extra length processing of the optical fiber becomes easy in connection with other devices, and the mounting restrictions can be relaxed.

  FIG. 8 shows a configuration of an optical module according to the fifth embodiment of the present invention. The quartz-LN modulator 710 is a multichip integrated device in which a quartz PLC 713 and an LN modulator 712 are connected and integrated, and is accommodated in a package 711. The quartz PLC 713 is connected to a surface (lower surface) opposite to the waveguide surface (upper surface) of the optical waveguide formed in the LN modulator 712 in the vicinity of one end of the LN modulator 712. Each of the waveguide end portions of the quartz PLC 713 and the LN modulator 712 is provided with a folding mechanism, and the optical waveguide formed in the LN modulator 712 and the optical waveguide formed in the quartz PLC 713 are optically connected. Are combined. In the LN waveguide 712, an optical fiber 714b integrated with the fiber connection component 720b is connected to an end face facing the surface optically connected to the quartz PLC 713. The two optical fibers 714 a and 714 b are taken out from the pipe portion 722. The support base 715 is made of quartz glass or the like, is a member for fixing the LN modulator 712 to the package 711, and has the same height as the quartz PLC 713.

  In a conventional two-chip multi-chip integrated module, a quartz PLC is connected to both ends of the LN modulator, and an optical fiber is connected to the connection end surface opposite to the end surface to which the LN modulator is connected in each quartz PLC. Since they were connected, it was necessary to take out the two optical fibers from the opposing surfaces in the longitudinal direction of the package. According to 5th Embodiment, there can exist the following effects.

  (1) Conventionally, one of the extra fiber length portions provided between the quartz PLC and the pipe portion is not necessary, and the quartz PLC connected on the same plane as the LN modulator is an LN modulator. Since it is installed on the lower surface, the package can be shortened in the longitudinal direction, that is, the package can be reduced in size. For example, in one embodiment, the length of a package that accommodates a conventional two-chip type multi-chip integrated module can be reduced from about 130 mm to about 110 mm.

  (2) According to the fifth embodiment, the same effects as (2), (4), and (5) shown in the first embodiment can be obtained. Regarding the effect (3) shown in the first embodiment, the distance between the connection points for fixing the optical fiber 714a is inevitably increased, and the buckling amount of the optical fiber is reduced or the bending radius of the buckling is increased. Can be bigger.

  (3) There is one pipe portion 722 of the package 711, and two optical fibers 714a and 714b can be taken out from the same surface of the package 711. Therefore, when the quartz-LN modulator 710 is mounted on a board in the communication apparatus, restrictions on mounting can be relaxed in connection with other devices.

  Next, with reference to FIG. 9, a method for accommodating the multichip integrated device of the first to fourth embodiments in a package will be described. In the first to fourth embodiments, stainless steel (for example, SUS303) is used as the package material. In this case, since the difference in thermal expansion coefficient between the quartz glass-based material and stainless steel is large, it is not preferable to directly fix the quartz PLC to the bottom surface of the package due to the problem of thermal stress. Therefore, as shown in FIG. 9A, the multichip integrated device in which the LN modulator 812 connected with the quartz PLCs 813a and 813b is integrated is fixed to a support base 841, and this support base 841 is attached to the bottom surface of the package. Fix it. The support base 841 is made of LN and has the same length as the LN modulator 812.

  According to this configuration, since the LN modulator 812 and the support base 841 perform the same amount of thermal expansion as the temperature changes, no positional deviation occurs. However, since the thermal expansion coefficients of the quartz PLCs 813a and 814b and the support base 841 are different, it is important to minimize the bonding area between the quartz PLCs 813a and 814b and the support base 841. Since the thermal expansion coefficients of the support base 841 and the package 811 are slightly different, it is preferable to minimize the adhesion area between the two.

  As shown in FIG. 9B, the quartz PLCs 913a and 913b can be integrated with the LN modulator 912 via a support base 942 made of stainless steel (for example, SUS303). The support base 942 is fixed on a convex support base 941 provided on the bottom surface of the package 911. The quartz PLCs 913a and 913b are bonded only to the support base 942, and are not bonded to the package 911.

  According to this configuration, since the support base 942 is strong and the thermal expansion coefficients of the stainless steel and the LN modulator 912 are substantially the same, the positional deviation between them can be suppressed to a small value. Further, since the quartz PLCs 913a and 913b can slide on the bottom surface of the package 911, the influence of thermal stress can be suppressed. On the other hand, the distance between the LN modulator 912 and the quartz PLCs 913a and 914b is increased by the thickness of the support base 942, which may cause a problem of beam expansion. This problem can be easily solved by providing a condensing lens as shown in FIG. Therefore, the merit that it can be firmly fixed to the support base 942 more than compensates for the problem of beam expansion.

  Further, the support base 941 can be a member separate from the package 911, and the material thereof can be the same as that of the quartz PLC. Since both have the same thermal expansion coefficient and the same thickness, as a result of the same displacement in the vertical direction, the quartz PLCs 913a and 913b do not float from the bottom surface of the package 911. On the contrary, the quartz PLCs 913 a and 913 b do not receive pressure between the package 911 and the support base 942.

  As shown in FIG. 9C, a support base 1041 made of quartz glass can be installed on the bottom surface of the package 1011, and the LN modulator 1012 can be fixed thereon. Due to the problem of thermal stress, the bonding area between the support base 1041 and the LN modulator 1012 is minimized, and the quartz PLCs 1013a and 1013b are not fixed to the bottom surface of the package 1011.

  According to this configuration, even if a shape change due to a temperature change occurs, the support pillar 1041 and the quartz PLCs 1013a and 1013b have the same thermal expansion coefficient and the same thickness. It will be the same. In other words, since the LN modulator 1012 is moved upwardly while being kept horizontal or pulled downward, the LN modulator 1012 can be prevented from being bent.

  In addition, since the quartz PLCs 1013a and 1013b are not fixed to the package 1011, even if a temperature change occurs, the quartz PLCs 1013a and 1013b only slide on the bottom surface of the package 1011 and can suppress the influence of thermal stress.

  Note that the same configuration as in FIG. 9 can be adopted for accommodating the multichip integrated device in the package in the fifth embodiment. That is, in the fifth embodiment, in the multichip integrated device of the first to fourth embodiments, a support base made of the same size and material is used instead of one quartz PLC among the two quartz PLCs. If considered, the same configuration as in FIG. 9 can be obtained.

10, 110, 410, 510, 610, 710, 810, 910, 1010 Quartz-LN modulator 11, 111, 411, 511, 611, 711, 811, 911, 1011 package 12, 112, 212, 312, 412, 512,612,712,812,912,1012 LN modulator 13,113,213,313,413,416,713,813,913,1013 quartz PLC
14, 114, 214, 314, 414, 514, 614, 714 Optical fiber 20, 120, 220, 320, 420 Fiber connection parts 21, 121, 221, 321, 421 End face for connection 22, 122, 422, 522, 622 , 722 Pipe portion 23 Fiber extra length portion 135 Condensing lens 715, 841, 941, 942, 1041

Claims (12)

In an optical module in which a multichip integrated device composed of a planar lightwave circuit (PLC) and an optical functional member is accommodated in a package,
The PLC includes an optical waveguide for connecting an optical fiber, and is connected to the optical functional member on a surface opposite to a waveguide surface of the optical waveguide formed on the optical functional member.
A folding mechanism for optically coupling the optical waveguides is provided at the waveguide end of the optical waveguide formed on the optical functional member and the waveguide end of the optical waveguide formed on the PLC. ,
The optical fiber is connected at the waveguide end opposite to the waveguide end provided with the folding mechanism among the waveguide ends of the optical waveguide of the PLC, and is taken out from the opposing surface of the package. An optical module characterized by the above. In an optical module in which a multichip integrated device composed of a planar lightwave circuit (PLC) and an optical functional member is accommodated in a package,
The PLC includes an optical waveguide for connecting an optical fiber, and is connected to the optical functional member on a surface opposite to a waveguide surface of the optical waveguide formed on the optical functional member.
A folding mechanism for optically coupling the optical waveguides is provided at the waveguide end of the optical waveguide formed on the optical functional member and the waveguide end of the optical waveguide formed on the PLC. ,
An optical waveguide for connecting an optical waveguide formed in the optical functional member and an optical fiber is formed in the first PLC of the PLC, and the optical function is provided in a second PLC of the PLC. An optical waveguide is formed that folds back and connects two optical waveguides formed on the member,
The optical module is connected to an optical waveguide for connecting the optical fiber of the first PLC, and is taken out from the same surface of the package.   The folding mechanism is a mirror in which the waveguide end portion of the optical waveguide formed in the optical functional member and the waveguide end portion of the optical waveguide formed in the PLC are ground at an angle of 45 degrees. The optical module according to claim 1 or 2.   The said folding mechanism includes a waveguide end portion of an optical waveguide formed in the optical functional member and a V-groove formed in the waveguide end portion of the optical waveguide formed in the PLC. 3. The optical module according to 1 or 2.   3. The optical module according to claim 1, wherein the optical fiber is taken out from a second surface that is in contact with a first surface facing the longitudinal direction of the package. In an optical module in which a multichip integrated device composed of a planar lightwave circuit (PLC) and an optical functional member is accommodated in a package,
The PLC includes an optical waveguide for connecting the first optical fiber, and is connected to the optical functional member on a surface opposite to the waveguide surface of the optical waveguide formed on the optical functional member,
A folding mechanism for optically coupling the optical waveguides is provided at the waveguide end of the optical waveguide formed on the optical functional member and the waveguide end of the optical waveguide formed on the PLC. ,
A first connection component for connecting the first optical fiber to an end of the PLC opposite to the folding mechanism;
A second connection component for connecting the optical waveguide formed in the optical functional member and the second optical fiber at an end opposite to the one end of the optical functional member;
The optical module, wherein the first and second optical fibers are extracted from the same surface of the package.   A support base having the same height as that of the PLC is connected to a surface opposite to the waveguide surface of the optical waveguide formed on the optical functional member at the opposite end. The optical module according to claim 6.   7. The PLC is fixed to the bottom surface of the package via a support base, and the thermal expansion coefficient of the support base is equal to the thermal expansion coefficient of the optical functional member. The optical module as described in.   The PLC and the optical functional member are fixed via a support base, and the support base is fixed to a support base formed on a bottom surface of the package. 7. The optical module according to 6.   The optical module according to claim 1, wherein the optical functional member is fixed to a bottom surface of the package by a support base having a thermal expansion coefficient equal to that of the PLC.   The optical module according to any one of claims 1 to 10, wherein the optical functional member is any one of a quartz glass material, a dielectric material, a semiconductor material, and an organic material. 11. The optical module according to claim 1, wherein the PLC is made of a quartz glass material, the optical functional member is LiNbO ₃ , and the multichip integrated device is an optical modulator.

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