JP5546410B2 - Optical member, optical communication module using the same, and alignment method - Google Patents

Description

  The present invention relates to an optical member that can be mounted on a plane, an optical communication module using the same, and an alignment method.

  Optical communication is widespread using an optical fiber as a transmission medium and a semiconductor laser as a light source. In optical communication, an electrical signal from a communication terminal is converted into an optical signal and transmitted from a semiconductor laser to an optical fiber. An optical member having an optical function surface such as a collimator lens or a cylindrical lens is used at the input / output portion of the semiconductor laser and the optical fiber, so that the light flux from the semiconductor laser is guided to the optical fiber with high coupling efficiency. A transmission / relay input / output unit or a reception input / output unit is assembled as an optical communication module.

  In general, the size of the light emitting portion of a semiconductor laser that is a light emitting element is about several μm, and the core diameter of an optical fiber that is a transmission medium is about 10 μm. Therefore, the assembly of the optical communication module requires an operation for accurately aligning the light emitting element, the optical fiber mounting portion, and the necessary optical members. When the optical path direction parallel to the horizontal plane is the Z-axis direction and the horizontal and vertical directions orthogonal to the optical path are the X-axis direction and the Y-axis direction, the X-axis direction and the Y-axis are set so that the optical axes of all optical members coincide. It is desirable to align the directions, and an optical communication module having the same optical axis can achieve high optical coupling efficiency.

  However, since the height of the light emitting portion of the semiconductor laser varies, it is necessary to adjust the optical axis in the height direction (Y-axis), and it is not easy to adjust the height and fix it after adjustment. That is, position adjustment in the horizontal direction (X-axis) and optical path direction (Z-axis) is possible by horizontally moving the XZ plane, whereas in the height direction (Y-axis) adjustment, It was necessary to provide a fine adjustment mechanism different from the above. Furthermore, for the purpose of miniaturization, an optical communication module that arranges and fixes a planar mountable optical member on a flat bench must be a position adjustment mechanism that can be miniaturized, and there is an adjustment method that allows easy position adjustment. It is desired.

  For example, Patent Document 1 describes a technique for adjusting and fixing the height of an optical fiber or the like in an optical communication module. Patent Document 1 discloses a method of preparing and selecting a plurality of members having different heights, and a method of adjusting the position in the height direction in a state where the horizontal position is adjusted and temporarily determined. In the former method, it is necessary to prepare a plurality of members and select them while confirming which member is the optimum member. In the latter method, it is necessary to combine two parts by a guide groove.

  Such alignment is necessary for each optical member constituting the optical communication module, and particularly in an optical member in which the position in the optical path direction (Z-axis) (for example, the focal position) is important, such as a lens, the horizontal direction. Position adjustment in the (X axis), height direction (Y axis), and optical path direction (Z axis) must also be performed. When the number of optical members of the optical system increases, it is a very complicated operation.

  Therefore, as a method of aligning the optical axes of a plurality of optical members, in addition to a method of precisely arranging the optical axes of all the optical members to coincide, for example, a method of correcting the optical axis deviation after arranging the main optical members Also done. If the optical axes of all the optical members do not match, the optical path of the lens temporarily placed with respect to the incident optical path is slightly shifted, so that the optical path transmitted through the lens is bent and the optical path toward the next optical member Adjust so that is closer to the optical axis. Further, an adjustment optical member for correcting the optical axis deviation may be additionally arranged. Patent Document 2 discloses that an optical axis can be corrected by arranging a plurality of prisms.

JP-A-7-333472 JP 2004-93661 A

  However, even in such a method for correcting the optical axis deviation, it is relatively easy to correct the optical axis deviation in the horizontal direction on the plane mounting surface, whereas it is difficult to correct the optical axis deviation in the vertical direction. there were.

  The present invention has been made in view of the above-described problems, and includes an optical member that can be easily aligned and can be mounted in a plane, and an optical communication module and an alignment method using the same. The purpose is to provide.

In order to solve the above problems, the present invention provides an optical member having a reference surface used for position adjustment, wherein the optical member has an optical functional surface having a refractive action of a cylindrical lens, and the optical functional surface is a generatrix of the cylindrical lens. And an optical axis direction of the cylindrical lens in a direction substantially parallel to the reference plane, and the reference plane adjusts a vertical position of the optical axis plane with respect to the luminous flux. wherein Ri surface der for fixing the optical member, with a surface parallel to the optical path direction of the light beam, wherein the generating line direction and having a predetermined angle theta.

  “Refractive action of a cylindrical lens” means a direction perpendicular to the generatrix direction without any refractive action in the generatrix direction of the cylindrical lens (the direction of the center line of the cylinder when approximated as part of the cylinder) The cross-sectional shape is an arc shape, and light is refracted in that direction, so that transmitted light is linearly collected on the optical axis plane. Therefore, if the optical path of the incident light beam coincides with the optical axis surface, the light beam travels straight, and if the optical path is deviated from the optical axis surface, the optical path of the transmitted light beam is different due to refraction.

  Accordingly, in the optical member having the reference surface, the vertical position of the optical axis surface with respect to the light beam can be adjusted by changing the relative position of the optical function surface in the vertical direction with respect to the optical path of the incident light beam. In this way, it is possible to correct the optical axis deviation and fix it at an optimum position. Therefore, it becomes easy to correct the optical axis deviation in the vertical direction.

In addition, the reference plane is a plane parallel to the optical path direction of the light beam and has a predetermined angle θ with respect to the generatrix direction, so that the optical axis surface for the light beam can be obtained by horizontally moving the optical member on the mounting plane. The vertical position of can be adjusted.

  The optical functional surface is preferably a Fresnel lens shape. A Fresnel lens is a general term for a lens obtained by dividing a normal lens and reducing its thickness, and has a saw-like cross section. As in the case of a Fresnel lens in which a general convex lens is concentrically divided, the cylindrical lens can be divided in the generatrix direction to cause the refractive action of the cylindrical lens. In this way, a thin optical design is possible, and a reduction in thickness and weight is possible.

  The Fresnel lens shape may be a diffractive Fresnel lens shape. A diffractive lens is a lens having a lens effect formed by forming a phase grating in a medium, and is also called a binary lens or a grating lens. The cross section of the diffractive lens having the refractive action of the cylindrical lens has a shape called a binary cylindrical lens. In this way, a thin optical member can be manufactured by a semiconductor processing technique, so that mass production is facilitated. Moreover, since glass or silicon excellent in heat resistance and long-term reliability can be used, it can be used for applications that require high reliability.

  In an optical communication module that performs optical transmission, the present invention includes at least a light emitting element that emits light, an attachment portion of an optical fiber that receives light from the light emitting element on an end surface, and the optical member of the present invention. It is characterized by. By doing so, it is possible to realize an optical communication module in which an adjustment operation for correcting the optical axis deviation is easy in the module assembly process in which the optical system in the module is arranged.

  Further, it is preferable that the light emitting element is a semiconductor laser that oscillates a laser beam, and the optical member is a beam shaping lens that corrects a beam shape of the semiconductor laser. In the case of a planar mounting type module, when the semiconductor laser is placed flat, the laser beam becomes a vertically long shape, and a beam shaping lens for making the laser beam circular is effective for high coupling efficiency of the optical communication module. By using the optical member of the present invention for this beam shaping lens, the optical axis misalignment correction function can be shared. By doing so, the optical communication module can be easily adjusted without correcting the components, and is suitable for downsizing.

  The present invention uses the optical member of the present invention in the alignment for correcting the optical axis deviation of the optical system, and the optical path of the light beam is adjusted by the adjusting means that moves the fixed position of the reference surface in a substantially horizontal direction. Is a centering method that corrects the optical axis deviation by transmitting in the vertical direction and changing in the vertical direction.

  Thus, by moving and adjusting the optical member that can be mounted in a plane in the substantially horizontal direction, the optical axis position in the direction perpendicular to the mounting plane can be changed to change the optical path of the light beam. Accordingly, vertical alignment is facilitated without providing a vertical fine adjustment mechanism.

  In the optical member according to the present invention, in the optical member having the reference surface, the relative position of the optical function surface can be changed in the vertical direction with respect to the optical path of the incident light beam. The position can be adjusted. This makes it possible to correct the optical axis deviation and fix it at an optimal position. Therefore, it becomes easy to correct the optical axis deviation in the vertical direction.

It is a schematic diagram which shows the optical member in 1st Embodiment. It is a schematic cross section of the optical communication module in a 1st embodiment. It is a principle figure which shows the refractive action of the cylindrical lens in 1st Embodiment, (a) is a top view, (b) is a side view. It is a schematic diagram of the focus position by the optical axis shift | offset | difference in a convergent lens effect | action. It is a front view of the optical member in the modification of 1st Embodiment. It is a front view of the optical member in 2nd Embodiment. It is a side view of the optical member in 3rd Embodiment. It is a schematic diagram of the optical function surface in 4th Embodiment. It is a schematic diagram of the optical function surface in 5th Embodiment. It is a schematic cross section of the optical communication module in 6th Embodiment. It is a schematic diagram which shows the beam shape of a semiconductor laser. It is a schematic cross section of the optical communication module in 6th Embodiment.

<First Embodiment>
Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an optical member 10 according to the first embodiment of the present invention, and FIG. 2 is a schematic view showing a cross section of the optical communication module 100 according to the first embodiment of the present invention. 3 and 4 are optical principle diagrams for explaining the refractive action of the cylindrical lens.

  FIG. 1 is a schematic diagram of an optical member 10. As shown in FIG. 1, the optical member 10 in this embodiment has an optical function surface 20 and a reference surface 10a used for positioning and fixing. The optical member 10 in the present embodiment can be mounted on the surface by fixing the reference surface 10a to a horizontal surface.

  In the description of the present embodiment, the direction of the light beam is defined as the Z-axis direction, and the horizontal and vertical directions orthogonal thereto are defined as the X-axis direction and the Y-axis direction. As shown in FIG. 1, the optical member 10 has a convex lens-shaped cross-sectional direction in which the optical function surface 20 has a converging function, and has a flat lens-shaped cylindrical lens shape in a cross-sectional direction orthogonal thereto. However, it is characterized by having an inclination of an angle θ slightly rotated around the Z axis.

  FIG. 2 is a schematic cross-sectional view of an optical communication module 100 using the optical member 10. It has a semiconductor laser 50 that is a light emitting element, an optical fiber mounting portion 60 that is a transmission medium, a collimating lens 70, a condensing lens 80, and the optical member 10 of the present invention. It is horizontally arranged on the substrate 90 so as to match. The optical member 10 fixes the reference surface 10 a to the substrate 90. An optical fiber (not shown) is attached to the optical fiber attachment portion 60, thereby being used for an optical communication system. The optical system of the optical communication module 100 is fixed by aligning during assembly so that light emitted from the semiconductor laser 50 can enter the optical fiber with high coupling efficiency.

  In order to show the characteristics of the optical member 10 in the present embodiment in detail, the “refractive action of the cylindrical lens” will be described. A cylindrical lens has a basic principle of a convex lens shape obtained by cutting a part of a cylinder. The refraction action of the cylindrical lens has no refraction action in the generatrix direction when the direction of the center line of the cylinder when defined approximately as a part of the cylinder is defined as the generatrix direction.

  The principle of this optical action will be described with reference to FIGS. 3A is a top view of the cylindrical lens 21 having a simple shape, and FIG. 3B is a side view. One optical surface of the cylindrical lens 21 has a flat lens shape arranged perpendicularly with respect to parallel rays having an optical path in the Z direction. In geometric optics, the optical axis is defined as a straight line perpendicular to both optical surfaces of the lens. That is, the light along the optical axis passes without being refracted. In contrast to a parallel beam having an optical path in the Z direction, a parallel beam spread in the X direction (the generatrix direction of the cylindrical lens) is transmitted without being refracted as shown in FIG. The parallel light beam spreading in the convex lens cross-sectional shape direction becomes a convergent light beam as shown in FIG. In the description of the optical principle, the convex lens is focused on one point, and the focal point is on the optical axis. In the case of the cylindrical lens 21, the convergent light beam is condensed linearly, and the condensing position in this case is defined as an effective focal plane F. Therefore, at the position of the effective focal plane F, linear condensing having a length corresponding to the light beam spread in the X direction is obtained. A surface formed by the optical axis 12 of the cylindrical lens 21 and the linear condensing is called an optical axis surface. In FIG. 3, the optical axis surface of the cylindrical lens 21 is an XZ plane in which the Y direction passes through the lens center (optical axis 12).

  The correction of the optical axis deviation in this specification means that when the optical axes do not match between the parts, the optical state is brought close to the optical state when the optical axes match by bending the optical path in the middle. Unlike the optical axis alignment in which the optical axes of the components coincide with each other at the position of the component arrangement, the correction of the optical axis deviation that bends the optical path uses the optical action of reflection or refraction. In alignment that adjusts the attachment of the optical component and fixes it at the optimum position, slight optical axis deviation (arrangement position deviation) can be corrected by bending the optical path. Next, this will be described.

  Consider a case in which a light beam having no spread is incident so as to coincide with the optical axis 12 (optical axis surface) of the cylindrical lens in FIG. Since the position of the effective focal plane F in the Y direction coincides with the optical axis 12, the Y direction height of the light beam goes straight with the same height as the optical axis 12 after passing through the lens. On the other hand, as shown in FIG. 4, when the cylindrical lens 21 is moved in the Y direction (height direction) with respect to the incident light beam 30, an optical axis misalignment 21 a or 21 b is obtained. In this case, since the position of the effective focal plane F in the Y direction changes to the height of the optical axis 12a or 12b of the cylindrical lens, it can be seen that the light beam 30 is bent in the Y direction (height direction). Therefore, if the position adjustment is performed so that the optical axis position of the cylindrical lens 21 is shifted in the Y direction (height direction), the incident light beam 30 can be bent in the Y direction (height direction). It can be used for alignment to correct the optical axis deviation in the vertical direction.

  On the other hand, it is a well-known optical principle that the optical axis does not deviate even if the cylindrical lens is moved in the generatrix direction. That is, in the case of the generatrix direction shown in FIG. 3A, the light beam goes straight no matter which position the light beam enters.

  The optical functional surface 20 in the optical member 10 shown in FIG. 1 is a lens having the refractive action of the above-described cylindrical lens, and has the feature of the present embodiment in that the optical axis surface changes in the X-axis direction. Accordingly, when the optical member 10 shown in FIG. 1 is fixed to the horizontal XZ plane with the reference plane 10a, the effective focal plane is obtained when the optical member 10 is moved along the XZ plane. Is moved in the Z direction, and in the movement in the X direction, incident parallel rays can be refracted in the Y direction. More specifically, in FIG. 1, the generatrix direction 22 in the refractive action of the cylindrical lens is inclined at an angle θ with respect to the X-axis direction. Since the bus-line direction 22 has an angle θ with respect to the X direction, the optical axis position shift (ΔY) in the Y direction when ΔX is moved in the X direction is ΔY = ΔX · tan θ. That is, the optical axis shift in the Y direction can be corrected by finely adjusting the fixed position of the optical member 10 in the X direction.

  Thereby, in the optical member 10 having the reference surface 10 a, the relative position of the optical function surface 20 can be changed in the vertical direction with respect to the optical path of the incident light beam 30, so that the optical axis surface is perpendicular to the light beam 30. The position can be adjusted. In this way, it is possible to correct the optical axis deviation and fix it at an optimum position. Therefore, it is easy to correct the optical axis deviation in the vertical direction (Y direction). The correction amount of the optical axis deviation varies depending on the arrangement state of the optical system, and is not limited to the effective focal plane position.

  In FIG. 1, when the angle θ is 0 degree, the optical axis shift in the Y direction cannot be corrected by movement in the X direction. When the angle θ is large, the amount of change in the Y direction increases with respect to the movement in the X direction, and the light beam 30 having a predetermined spread cannot be ignored in the θ direction. Therefore, the angle θ is preferably greater than 0 degree and 30 degrees or less. More preferably, it is 5 to 10 degrees. Within this range, it is suitable for fine adjustment of the fixed position of the optical system, and the influence on the coupling efficiency of the optical system is small. In this way, the vertical position of the optical axis plane with respect to the light beam 30 can be adjusted by moving the optical member 10 horizontally on the mounting plane. Therefore, it becomes easy to correct the optical axis deviation in the vertical direction.

  The reference surface 10a is an attachment surface that serves as a reference for fine adjustment work, and the bottom surface of the optical member 10 in FIG. 1 is used as a flat reference surface 10a (attachment surface) so that it can be fixed at an arbitrary position in planar mounting. Yes. In the conventional alignment method, even if the movement in the direction parallel to the component installation surface (substrate surface) is relatively easy, the movement in the direction perpendicular thereto is difficult. For alignment in the vertical direction, it is often the case that several types of parts with different heights from the mounting surface to the center of the optical axis are prepared and selected for use. In this case, the fine adjustment cannot be continuously performed, and the optimum height adjustment cannot be obtained. Therefore, the alignment method according to the present embodiment has a very excellent effect because the fine adjustment can be continuously performed.

  Up to now, it has been known to use an optical system in which only the optical axis surface of the cylindrical lens is shifted from the other lens optical axis by a predetermined amount. However, this arrangement is due to reasons such as avoiding performance degradation due to reflected light. there were. In the present embodiment, the optical axis shift is corrected by moving the optical axis plane of the cylindrical lens in the vertical direction, which is different from the optical system for shifting the predetermined amount. For example, if the optical axis coincides with a state in which there is no optical axis deviation in advance, no correction is necessary, so the state is different from an optical system that has been shifted a predetermined amount in advance. In addition, when there is a deviation of the optical axis, continuous adjustment can be made to achieve the required correction amount, and a mechanism that moves in the horizontal direction, not a mechanical vertical movement mechanism that moves in the height direction. There is a feature in this embodiment.

  The optical function surface 20 may be a cylindrical lens surface for both optical surfaces as well as one surface of the optical member 10. For example, a cylindrical lens surface can be formed such that one side is convex and the other side is concave. Similarly to a general lens, a cylindrical lens can be optically designed to reduce aberration when spherical aberration becomes a problem. Therefore, strictly speaking, there may be a case where a simple shape obtained by cutting out a part of the “cylinder” is not obtained. In the present specification, not only a simple shape of a part of a cylinder or a cylindrical surface but also a complicated geometrical shape with less aberrations and those having the refractive action of a cylindrical lens are collectively referred to as a cylindrical lens. Also, the bus direction is defined in the same direction as that of a simple cylindrical lens, so that it can be applied to a complicated geometric shape.

  Further, in a simple cylindrical cylindrical lens, the cross-sectional shape cut in the direction perpendicular to the generatrix direction is an arc, but in the optical member 10 having the angle θ, the surface cut in the vertical direction is an arc (slant). It is possible to design the outer shape of the cylinder. Also in this case, a geometric shape that reduces spherical aberration can be designed. In this way, a cylindrical lens having a convergence effect in the vertical direction regardless of the angle θ and having a generatrix of the angle θ in the horizontal direction can be obtained.

  The geometric shape is not limited as long as it is an optical functional surface 20 having a refractive action of a cylindrical lens, but in this specification, in order to express the directional relationship between the optical path direction of the light beam and the refractive action of the cylindrical lens, the geometric shape is not limited. It uses the generatrix and normal directions of a cylindrical lens with a geometric shape. In FIG. 1, the optical functional surface 20 is configured by only one surface of the optical member 10, but the optical functional surface 20 may be formed on both surfaces of the optical member 10 to perform the refractive action of the cylindrical lens.

  In the present embodiment, the optical functional surface 20 is a lens formed of glass, and the optical member 10 is a lens-integrated type. Such a lens may be integrally formed at the same time as the optical member 10 is formed, or a lens and a lens mounting member may be integrated. FIG. 5 shows a modification of the optical member 10 manufactured separately for the lens and the lens mounting member. The joining surface of the lens and the lens mounting member is also a reference surface 10b. When the reference surface 10b is fixed and then disposed, it is the same as the optical member 10 of FIG. 1, but in the case of FIG. 5, the reference surface 10b can be used for correcting the optical axis deviation and fixed after adjustment.

  In addition to glass, the material of the optical functional surface 20 can be selected and used according to the optical wavelength to be applied, such as plastic, resin, calcium fluoride, silicon and silicon compound. Note that glass or silicon is suitable when high reliability is required.

<Second Embodiment>
The optical functional surface 20 of the optical member 10 is not limited to the embodiment shown in FIG. 1 as long as it has an angle θ between the generatrix direction in the refraction action of the cylindrical lens and the reference surface 10a used for positioning and fixing. . For example, the reference plane 10a may not be horizontal. FIG. 6 is a front view of the optical member 10 according to the second embodiment.

  In the optical member 10 of FIG. 6, the generatrix direction in the refraction action of the cylindrical lens is the horizontal direction (X axis), and the reference surface 10 a is in contact with the base portion 25. The base 25 is mounted on a horizontal surface with a fixed surface 25 b and supports the optical member 10. The base 25 has an adjustment surface 25a and a fixed surface 25b, and both surfaces are inclined at an angle θ. Therefore, by moving the reference surface 10a along the adjustment surface 25a, the optical function surface 20 is also moved in the Y direction. Thereby, it can be made to function so that the position of the optical function surface 20 can be adjusted with respect to the incident light beam. Therefore, the optical axis shift in the Y direction can be corrected by finely adjusting the fixed position of the optical member 10 in the X direction.

<Third Embodiment>
In order to move the position of the optical function surface 20 in the Y direction, the optical function surface 20 may be configured to move in the Z direction in addition to the structure that moves in the X direction. FIG. 7 is a side view of the optical member 10 according to the third embodiment. In the present embodiment, the reference surface 10a is arranged so as to be inclined with respect to the Z axis by an angle θ. The base 26, the adjustment surface 26a, and the fixed surface 26b are different only in the inclination directions of the base 25, the adjustment surface 25a, and the fixed surface 25b in the second embodiment. By so doing, the present embodiment can also function so that the position of the optical function surface 20 can be adjusted with respect to the incident light beam. Therefore, the optical axis shift in the Y direction can be corrected by finely adjusting the fixed position of the optical member 10 in the Z direction.

  In the first to third embodiments, the optical functional surface 20 is not limited to a cylindrical lens-shaped geometric surface, and may be, for example, a gradient index (GRIN) lens surface. Although the refractive index distribution lens does not necessarily have a convex shape as shown in FIGS. 1, 2, and 7 as a lens shape, a lens having a refractive action of a cylindrical lens can be applied in the same manner as described above. In this case, the direction of the generatrix cannot be defined from the geometrical shape, but it is widely interpreted as a direction based on the above-described refraction action principle.

<Fourth Embodiment>
FIG. 8 is a schematic diagram for illustrating an optical function surface 20 in the fourth embodiment. Similar to the first to third embodiments described above, the cylindrical lens has a one-dimensional Fresnel lens shape having a convex curvature, and has a refractive action that converges in the Y direction. By doing so, the optical functional surface 20 is thin, and the optical member 10 can be made lighter.

<Fifth Embodiment>
FIG. 9 is a schematic diagram for illustrating an optical function surface 20 in the fifth embodiment. The optical functional surface 20 forms a diffractive lens shape and has a refractive action of a cylindrical lens. Such a diffractive lens shape can also be called a binary Fresnel lens shape.

  The phase of the diffractive lens is determined as a function of wavelength, and the film thickness of each stage is set. In the present embodiment, it is desirable to have a multi-level binary Fresnel lens shape having 4 to 8 phases.

  By doing so, the optical member 10 can be made thin and light. Furthermore, since it can be manufactured by semiconductor processing technology, mass production becomes easy. Moreover, the base material formed in a diffractive lens shape is glass. In addition to glass, plastic or silicon may be used. Silicon is transparent in the wavelength region of light used for optical communications (infrared region such as 1.3 μm, 1.55 μm, etc.) and has a larger refractive index than glass, so it can be made thinner. By using silicon as a lens base material, fine processing with submicron accuracy can be easily performed using semiconductor processing technology. Since glass or silicon is excellent in heat resistance and long-term reliability, it can be used for applications that require high reliability.

<Sixth Embodiment>
FIG. 10 is a schematic diagram showing a cross section of an optical communication module 110 to which the optical member 10 according to the present invention is applied as one of optical components. A surface-mounted optical communication module 110, which is an optical member 10, a semiconductor laser 50 that is a light emitting element, a semiconductor laser fixing base 55, a collimator lens 70, a beam shaping lens 75, a condensing lens 80, and an optical fiber mounting portion 60. A substrate 90 and a housing 95 are included.

  The optical member 10 of the present invention is disposed between the beam shaping lens 75 and the condensing lens 80, and aligns the optical axis so that the light beam emitted from the semiconductor laser 50 enters the optical fiber fixed to the optical fiber mounting portion 60. To do. Here, the substrate 90 is a flat optical bench, and each optical component to be installed is finely adjusted in the horizontal direction (direction Z of light beam and direction X orthogonal to the light beam), and is fixed by an adhesive or the like. It should be noted that the optical fiber may be either temporarily connected at the time of assembly or when an adjustment monitor is attached at the time of assembly and does not include the optical fiber.

  In the optical communication module 110 of FIG. 10, the beam emitted from the semiconductor laser 50 that is a light source is divergent light, and is collimated by the collimator lens 70. Beams emitted from the semiconductor laser 50 have different divergence angles in the vertical direction and the horizontal direction, and their cross-sectional shapes are elliptical. For example, the beam shape is as schematically shown in FIG. Thus, since the beam spread in the vertical direction Y emitted from the collimating lens 70 is larger than the beam spread in the horizontal direction X, it is shaped into a circular beam shape using the beam shaping lens 75 having a cylindrical lens action. The The optical design of the optical member 10 and the beam shaping lens 75 is optimized so as to be focused on the optical fiber with an optimal beam shape.

  In this way, the beam shaping lens 75 and the optical member 10 can optimize the circular beam shape, and the optical member 10 can perform position adjustment for correcting the optical axis deviation of the optical system. Therefore, it is possible to realize an optical communication module that can easily perform an adjustment operation for correcting an optical axis shift in a module assembly process in which an optical system in the module is arranged.

  The optical member 10 may be disposed between the collimating lens 70 and the beam shaping lens 75.

<Seventh Embodiment>
Since the optical member 10 in the present embodiment has a beam shaping action similar to that of the beam shaping lens 75, the optical member 10 can also have the effect of the beam shaping lens 75. As shown in FIG. 12, the optical member 10 includes an optical member 10, a semiconductor laser 50 that is a light emitting element, a semiconductor laser fixing base 55, a collimator lens 70, and a condenser lens 80. In addition to shaping the light emitted from the collimating lens 70 into a circular beam shape, it also serves as a centering function for correcting optical axis deviation.

  By doing so, the adjustment work for correcting the optical axis deviation is facilitated without increasing the number of components, which is suitable for downsizing.

  Furthermore, the optical axis misalignment correction method using the optical member 10 described in detail in the present embodiment is not limited to the optical communication module, and can be widely applied when the optical system is arranged and adjusted on a flat optical bench. Technology. For example, the optical member 10 can be arranged for optical axis misalignment correction in a holographic application system or a planar mounting of an optical system in a laser radar device or the like. Thereby, the optical axis deviation in the direction perpendicular to the reference surface 10a can be corrected by finely adjusting the position of the optical member 10 substantially horizontally on the reference surface 10a. Therefore, it is possible to optimally arrange the optical system without separately providing a fine adjustment mechanism in the vertical direction on the reference surface 10a.

  The optical member 10 described in detail in the present embodiment can be applied to a planar mounting optical system, and the application product field is not limited to the optical communication module. For example, the optical member 10 can be used in an optical disk memory device, a copying machine, an optical reader, a laser radar device, or the like.

  The planar mounting described in the first to seventh embodiments does not define the horizontal accuracy in the assembly process. Any plane that is substantially perpendicular to gravity may be used. Moreover, the up-down direction after assembly and fixing is not limited to the above-described plane mounting direction, and the optical path direction when using the applied product may not be a horizontal plane.

DESCRIPTION OF SYMBOLS 10 Optical member 10a, 10b Reference surface 12, 12a, 12b Optical axis 20 Optical function surface 21 Cylindrical lens 22 Bus-line direction 25, 26 Base 25a, 26a Adjustment surface 25b, 26b Fixed surface 30 Light beam 50 Semiconductor laser 55 Semiconductor laser fixing stand 60 Optical fiber mounting portion 70 Collimating lens 75 Beam shaping lens 80 Condensing lens 90 Substrate 95 Housing 100, 110, 120 Optical communication module

Claims (6)

In an optical member having a reference surface used for position adjustment,
The optical member has an optical functional surface having a refractive action of a cylindrical lens;
The optical functional surface has an optical path direction of a light beam orthogonal to a generatrix direction of the cylindrical lens, and an optical axis surface of the cylindrical lens in a direction substantially parallel to the reference surface,
The reference surface is Ri surface der for fixing the optical member as well as adjust the vertical position of the optical axis plane with respect to the light beam, as well as a plane parallel to the optical path direction of the light beam a predetermined angle from said generatrix direction An optical member having θ . The optical member according to claim 1, wherein the optical functional surface has a Fresnel lens shape. The optical member according to claim 2 , wherein the Fresnel lens shape is a diffractive Fresnel lens shape. In an optical communication module that performs optical transmission,
A light emitting element that emits light;
An optical fiber attachment for receiving light from the light emitting element on the end face;
The optical member according to any one of claims 1 to 3 ,
An optical communication module comprising: The light emitting element is a semiconductor laser that oscillates a laser beam,
The optical communication module according to claim 4 , wherein the optical member is a beam shaping lens that corrects a beam shape of the semiconductor laser. In alignment to correct the optical axis deviation of the optical system,
Using the optical member according to any one of claims 1 to 3 ,
By adjusting means for moving the fixed position of the reference surface in a substantially horizontal direction,
By changing the optical path of the luminous flux in the vertical direction through the optical member,
An alignment method, wherein the optical axis deviation is corrected.

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