JP4408123B2 - Optical multiplexer / demultiplexer - Google Patents

Description

  The present invention relates to an optical multiplexer / demultiplexer, and more particularly to an optical multiplexer / demultiplexer that can monitor the power of output light or input light of each wavelength.

  An example of a conventional optical multiplexer / demultiplexer is shown in FIGS. This optical multiplexer / demultiplexer includes a mirror array block 100, a waveguide mirror block 110 having a reflecting surface, a filter block 120 having a beam splitter 121, and an optical fiber 130.

  The mirror array block 100 is formed on the surface of the plate-like substrate along the side wall portion 101a at the side wall portions 101a, 101b, 101c formed at the three substrate end portions and the substrate end portion where the side wall portion 101a is formed. Inclined surface 102, concave mirror 103 formed by being arranged along the linear axis direction of V groove 102 on one inclined surface 102a constituting V groove 102, and perpendicular to the linear axis direction of V groove 102. And a plurality of linear V grooves 104 formed so as to be opposed to the concave mirror 103 and connected to the V groove 102. An inclined surface 105 for holding the waveguide mirror block 110 and an inclined surface 106 for holding the filter block 120 are formed on the side wall 101b and the side wall 101c.

  Such an optical multiplexer / demultiplexer is manufactured by mounting the optical fiber 130 on the V groove 104 and fixing the mirror block 110 and the filter block 120 to the mirror array block 100. At this time, the end portion of the optical fiber 130 facing the concave mirror 103 is disposed at a predetermined distance from the concave mirror 103.

JP 2005-274702 A

  When performing wavelength division multiplexing transmission, it is necessary to always monitor whether or not the power of the optical signal of each wavelength is appropriate in order to ensure the signal quality of each wavelength multiplexed wavelength. However, since the conventional optical multiplexer / demultiplexer described above does not have a means for monitoring the power of the optical signal, the power of the optical signal of each wavelength obtained by demultiplexing the wavelength multiplexed light and the wavelength of each wavelength before multiplexing are combined. When monitoring the power of the optical signal, it is necessary to provide a separate optical power monitor outside the multiplexer / demultiplexer.

The optical power monitor has an optical connector for optical input and an optical connector for optical output, and a part of the light incident from the optical connector for input is received by a light receiving element, and the remaining light is output for output. By outputting from the connector, the power of light is measured. In such an optical power monitor, two optical fiber cords are connected to a cylindrical main body, and an optical connector is attached to the optical fiber cord, and an optical power monitor including the optical connector is often used. The volume of is equal to or larger than that of a small-sized optical multiplexer / demultiplexer commercially available in recent years. Therefore, for example, when all the outputs of the 8ch optical demultiplexer are monitored, it is necessary to attach eight optical power monitors. When it is assumed that the volume of one optical power monitor is 4 cm ³ , only the optical power monitor is used. A volume of 32 cm ³ or more is required. For this reason, when the miniaturization of the optical multiplexer / demultiplexer has been promoted, an optical power monitor requiring a large volume is required outside the optical multiplexer / demultiplexer, and the entire apparatus cannot be miniaturized.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical multiplexer / demultiplexer that can be downsized.

In order to solve the problems as described above, an optical multiplexer / demultiplexer according to the present invention includes a reflective condensing element configured of a concave mirror and reflecting light incident from a first direction in a second direction. , Arranged on one of the optical axes in the first direction and the second direction, and formed at a substantially central portion of the mirror of the reflection condensing element and a light beam branching element that transmits or reflects light according to the wavelength And a reflecting member that reflects a part of the light incident on the reflective condensing element in the third direction, and a light receiving element that detects the power of the light reflected by the reflecting member , the first direction and An optical fiber is disposed on the optical axis of the second direction where the light beam branching element is not disposed, and the reflection condensing element includes a light beam that enters or exits from an end surface of the optical fiber, and a light beam that passes through the light beam branching element. Function as an optical fiber coupling element Reflecting member, projecting from the mirror reflective focusing elements, the mirror and the angle and said Rukoto such a different reflecting surface.

  According to the present invention, by providing a reflecting member that reflects part of the light incident on the reflective condensing element in the third direction, and a light receiving element that detects the power of the light reflected by the reflecting member. By detecting the output of the light receiving element, it is possible to measure the optical power to be demultiplexed or combined, so that there is no need to provide an external power monitor as in the prior art, resulting in a reduction in size. Can be realized. Further, since it is not necessary to provide a power monitor, it is not necessary to perform complicated connection work, and convenience can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
First, a first embodiment of the present invention will be described. As shown in FIGS. 1 to 3, the optical multiplexer / demultiplexer according to the present embodiment includes a main block 1, a fiber unit 2 mounted on the main block 1, and a light receiving element 32 fixed to the main block 1. Is formed, a waveguide mirror block 4 fixed to the main block 1 and having a reflective element 42 formed thereon, and a filter block 5 fixed to the main block 1 and having a beam splitter 52. It is an optical multiplexer / demultiplexer.

<Main block 1>
As shown in FIGS. 1 to 4, the main block 1 includes a plate-like base portion 11 and three side wall portions 12 a, 12 b, and 12 c formed at the end portion of the base portion 11. Here, the side wall part 12b and the side wall part 12c are formed facing each other. Further, a plurality of concave mirrors 6 functioning as reflective condensing elements are formed on the inner side surface of the main block of the side wall portion 12a, that is, the side surface adjacent to the base portion 11.

  On the base 11, there is a plane portion 13 composed of a plane inclined toward the side wall portion 12 a in order from the side wall portion 12 a toward the end facing the side wall portion 12 a, and the side wall has a substantially V-shaped cross section. A fiber unit mounting portion 16 having a groove forming portion 14 in which a plurality of grooves 14a parallel to the portion are formed, a gap portion 15 in which a plane is formed, and a concave portion 16a that is dug into the base portion 11 and is substantially rectangular in plan view. And are formed.

  On the opposing side wall portions 12b and 12c, a mirror block holding portion 17 and a filter block holding portion 18 that are inclined at a predetermined angle with respect to the main surface of the substrate 11 are formed. The mirror block holding part 17 is formed closer to the concave mirror 6 than the filter block holding part 18. The mirror block holding part 17 is formed with two protrusions 17a for positioning the waveguide mirror block 4 on both sides of the side wall parts 12b and 12c. Similarly, the mirror block holding part 18 is formed with two protrusions 18a for positioning the mirror block 5 on both sides of the side wall parts 12b and 12c.

  Further, a light receiving element block holding portion 19 is formed on the upper portion of the side wall portion 12a and the end portions of the side wall portions 12b and 12c on the side wall portion 12a side. The light receiving element block holding portion 19 includes a flat surface 19a formed substantially parallel to the base portion 11 over the side wall portions 12a to 12c, and a projecting portion 19b extending from the side wall portions 12b and 12c vertically upward of the flat surface 19a. Consists of.

<Fiber unit 2>
As shown in FIG. 5, the fiber unit 2 includes a lower holding substrate 21 formed with a plurality of grooves parallel to each other on the upper surface, an upper holding substrate 22 formed with a plurality of grooves parallel to each other on the lower surface, and a lower holding substrate. 21 and an upper holding substrate 22 and a plurality of optical fibers 23 fixed in parallel to each other. Here, the grooves formed in the lower holding substrate 21 and the upper holding substrate 22 are formed at the same pitch as the grooves 14 a formed in the groove forming portion 14 of the main block 1.

  Such a fiber unit 2 is disposed on the main block 1 by fitting the lower holding substrate 21 into the recess 16a of the main block 1 with one end of the optical fiber 23 facing the side wall 12a. The A part of the optical fiber 23 on the one end side is fitted into the groove 14a. On the groove forming portion 14 in which the optical fiber 23 is fitted in the groove 14a, the pressing plate 7 is bonded and fixed. Thereby, the fiber unit 2 is fixed on the main block 1.

<Light receiving element block 3>
As shown in FIG. 6, the light receiving element block 3 includes a light receiving element mounting substrate 31 having a substantially rectangular plate shape in plan view, and a lower surface 31 a of the light receiving element mounting substrate 31 along the longitudinal direction of the light receiving element mounting substrate 31. And a plurality of light receiving elements 32 made of photoelectric conversion elements, and an electrical connector 33 provided at one end in the longitudinal direction of the light receiving element mounting substrate 31. The light receiving element 32 is connected to the electrical connector 33 by a wiring pattern (not shown) formed on the lower surface 31 a or the upper surface 31 b of the light receiving element mounting substrate 31. As a result, the output from the light receiving element 32 is extracted to the outside via the electrical connector 33.

  Such a light receiving element block 31 is fixed to the main block 1 by sandwiching both ends in the longitudinal direction of the light receiving element mounting substrate 31 between the flat surface 19a and the protrusion 19b of the light receiving element block holding portion 19. At this time, the light receiving element mounting substrate 31 is arranged in a state in which the longitudinal direction coincides with the extending direction of the side wall portion 12 a of the main block 1 and the lower surface 31 a faces the substrate 11 of the main block 1. As a result, the light receiving element 32 is substantially opposed to the concave mirror 6.

<Waveguide mirror block 4>
As shown in FIG. 7, the waveguide mirror block 4 has a support portion 41 having a substantially concave plate shape in plan view, and an array on one surface (hereinafter referred to as a mirror surface) 41a of the support portion 41. And a plurality of reflective elements 42 formed on the substrate. Further, a projection 43 for holding the waveguide mirror block 4 at the time of assembly is formed on a surface 41b (hereinafter referred to as an adhesion surface) 41b opposite to the mirror surface 41a of the support portion 41.

  Such a waveguide mirror block 4 is positioned by the protrusion 18a with the adhesive surface in contact with the mirror block holding portion 18 of the main block 1. Thereafter, the waveguide mirror block 4 is fixed to the main block 1 with an adhesive. A recess corresponding to the shape of the protrusion 18a may be formed at a position facing the protrusion 18a of the waveguide mirror block 4. Thereby, the waveguide mirror block 4 can be positioned at a predetermined position.

<Filter block 5>
As shown in FIG. 8, the filter block 5 includes a support portion 51 having a substantially rectangular plate shape in plan view, and a plurality of beam branching elements 52 formed in an array on one surface of the support portion 51. Prepare. The beam splitter 52 is disposed so as to block a plurality of holes 53 formed in an array at a portion of the support 51 through which the beam passes. The beam splitter 52 is formed by depositing a dielectric multilayer film on a glass substrate.

  Such a filter block 5 is positioned by bringing the surface opposite to the side where the light beam splitting element 52 is provided into contact with the protrusion 17 a formed on the filter block holding portion 17. At this time, the filter block 5 can be accurately positioned by forming a recess corresponding to the shape of the protrusion 17 a at a position facing the protrusion 17 a of the filter block 5. After positioning in this way, the filter block 5 is fixed to the main block 1 with an adhesive.

<Concave mirror 6>
As shown in FIGS. 4A and 4B, the concave mirror 6 is formed at one end (in the present embodiment, on the side wall 12c side) of the plurality of concave mirrors 6 provided on a straight line. And a concave mirror 6-2 to 6-n having two curved surfaces of a fiber coupling curved surface 61 and a light receiving element coupling curved surface 62.

  The curvature and angle of the curved surface 61 for fiber coupling are set so that the light beam entering and exiting from the end face of the optical fiber 23 and the light beam passing through the light beam splitting element 52 are coupled.

  The curved surface 62 for coupling the light receiving element functioning as a reflecting member has a curvature and an angle so that a part of the light beam incident / exited from the end face of the optical fiber 23 or the light beam transmitted through the beam branching element 52 is incident on the light receiving element 32. Is set. Such a light receiving element coupling curved surface 62 is provided on an edge portion or a peripheral portion of the fiber coupling curved surface 61 on the side close to the base portion 11 of the main block 1.

[Operation of optical multiplexer / demultiplexer]
Next, the operation principle of such an optical multiplexer / demultiplexer as a demultiplexer will be described with reference to FIGS. 9 to 11 schematically show the optical multiplexer / demultiplexer shown in FIGS. 1 to 8 for ease of explanation. In FIG. 10, for the sake of convenience, the light receiving element 32 and the optical axis to the light receiving element 32 are not shown.

  The wavelength multiplexed light input from the outside of the optical multiplexer / demultiplexer propagates through the optical fiber 23-1, is guided into the optical multiplexer / demultiplexer, and is emitted as a wavelength multiplexed light slightly diffused to the concave mirror 6-1. The The concave mirror 6-1 reflects the emitted wavelength-multiplexed light as a collimated light or a substantially collimated light and propagates it to the reflecting element 42-1. The propagated reflected multiple rays are reflected again by the reflecting element 42-1, and enter the beam branching element 52-1.

  The wavelength multiplexed light incident on the light beam splitting element 52-1 is transmitted through the light beam splitting element 52-1 as a single color light beam including a specific wavelength region, and enters the concave mirror 6-2. As shown in FIG. 11, this concave mirror is a combination of two concave surfaces: a curved surface 61 for coupling an optical fiber and a curved surface 62 for coupling a light receiving element formed at the edge of the optical fiber coupling curved surface 61 on the base 11 side. It is made up of. The optical fiber coupling curved surface 61 is formed so as to receive most of incident light rays (about 95% or more). As a result, most of the incident light (approximately 95% or more) is reflected and collected by the fiber coupling curved surface 61 in the direction of the optical fiber 23-2, passes through the optical fiber 23-2, and is optically multiplexed / demultiplexed. Is output to the outside. On the other hand, the light receiving element coupling curved surface 62 formed at the edge of the optical fiber coupling curved surface 61 is formed so as to have a different curvature and angle from the optical fiber coupling curved surface 61, and the incident light is received by the light receiving element 32-. Reflect in the direction of 1. Accordingly, of the light rays incident on the concave mirror 6-2, the remaining light other than that incident on the optical fiber coupling curved surface 61 is reflected in the direction of the light receiving element 32-1 by the light receiving element coupling curved surface 62 and collected. Light is incident on the light receiving element 32-1.

  At this time, the relationship between the optical power output from the optical fiber 23-2 and the amount of current output from the light receiving element 32-1 is measured in advance, and then from the light receiving element 32-1 during the demultiplexing operation. , The optical power output from the optical fiber 23-2 can be estimated from the measured value and the above relationship.

  Among the wavelength-multiplexed light beams incident on the light beam branching element 52-1, light beams outside the specific wavelength range are reflected by the light beam branching element 52-1, propagated to the reflecting element 42-2, and reflected by the reflecting element 42-2. And enters the beam splitter 52-2. The monochromatic light beam transmitted through the light beam splitting element 52-2 is incident on the concave mirror 6-3. Most of the light beam is incident on the optical fiber 23-3 by the fiber coupling curved surface 61, and the rest is received by the light receiving element coupling curved surface 62. -2 reflected.

  The above-described process is repeated between the optical fibers 23-1 to 23-5, the concave mirrors 6-1 to 6-5, the reflecting elements 42-1 to 42-4, and the beam splitters 52-1 to 52-3. Thus, the wavelength multiplexed light incident from the optical fiber 23-1 is taken out from the optical fibers 23-2 to 23-5 as a plurality of demultiplexed monochromatic light beams, and from the light receiving elements 32-1 to 32-4. By observing the output current, the optical power output from the optical fibers 23-2 to 23-5 can be estimated.

  As described above, according to the present embodiment, the concave mirror 6 combines the light beam that enters and exits from the end face of the optical fiber 23 and the light beam that passes through the light beam splitting element 52, and one of the light beams. By configuring the portion with the light receiving element coupling curved surface 62 that introduces the light receiving element 32, it is possible to measure the optical power to be demultiplexed or combined by detecting the output of the light receiving element 32. Therefore, it is not necessary to provide a known power monitor, and thus downsizing can be realized.

  Further, when an optical power monitor is provided as in the prior art, it is necessary to connect each channel with an optical connector, so that the connection work is complicated and inconvenient. However, according to the present embodiment, since it is not necessary to provide a power monitor, a complicated connection work is not required, and convenience can be improved.

  In addition, when using the optical multiplexer / demultiplexer which concerns on this embodiment as a multiplexer, it can implement | achieve by making the advancing direction of the wavelength multiplexed light and monochromatic light in the above-mentioned demultiplexing operation reverse. That is, by inputting monochromatic light into the optical fibers 23-2 to 23-5 from the outside of the optical multiplexer / demultiplexer, the plurality of monochromatic light beams are combined as wavelength-multiplexed light beams from the optical fiber 23-1. It will be taken out. At this time, the optical power input from the optical fibers 23-2 to 23-5 can be estimated by observing the output current from the light receiving elements 32-1 to 32-4.

  As described above, when the optical multiplexer / demultiplexer according to the present embodiment is used as a demultiplexer, as shown in FIG. 11, from the light beam splitting elements 52-1 to 52-4 to the light receiving element coupling curved surface 62-. The angles and curvatures of the light receiving element coupling curved surfaces 62-2 to 62-5 are set so that parallel light rays (or light beams slightly diffused) incident on 2 to 62-5 are collected on the light receiving element 32. On the other hand, when the optical multiplexer / demultiplexer according to the present embodiment is used as a multiplexer, a part of the diffused light emitted from the optical fibers 23-2 to 23-5 is received by the light receiving element 32 as shown in FIG. The angles and curvatures of the light receiving element coupling curved surfaces 62-2 to 62-5 are set so that the light is condensed. Therefore, the constituent elements other than the light receiving element coupling curved surfaces 62-2 to 62-5 can be used in common without changing the shape, arrangement, etc., when used in any of the multiplexer and the demultiplexer. it can.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. This embodiment is different from the first embodiment described above in the configuration of the concave mirror 6, and the other components are the same. Therefore, the same components and components as those in the first embodiment are denoted by the same names and reference numerals, and the description thereof is omitted as appropriate.

<Concave mirror 6>
The concave mirror 6 is formed at one end (on the side wall 12c side in the present embodiment) of the plurality of concave mirrors 6 provided on a straight line, and has a single curved surface, as shown in FIG. As shown in FIG. 14, it is composed of concave mirrors 6-2 to 6-n having two curved surfaces of a fiber coupling curved surface 61 and a light receiving element coupling surface 63.

  The curvature and angle of the curved surface 61 for fiber coupling are set so that the light beam entering and exiting from the end face of the optical fiber 23 and the light beam passing through the light beam splitting element 52 are coupled.

  The light receiving element coupling surface 63 that functions as a light receiving element reflecting portion is formed of a curved surface formed at a substantially central portion of the fiber coupling curved surface 61. Such a light receiving element coupling surface 63 has a curved surface curvature and angle set so that a part of the light beam that is transmitted through the light beam splitting element 52 and is incident on the concave mirror 6 is reflected toward the light receiving element 32. Yes. In the present embodiment, the light receiving element coupling surface 63 is projected from the fiber coupling curved surface 62. Thereby, since the inclination angle of the surface of the light receiving element coupling surface 63 can be increased, the degree of freedom of the position where the light receiving element 32 is provided can be increased.

  The light beam that passes through the light beam splitting element 52 and enters the concave mirror 6 is a Gaussian beam, and has the highest light intensity at the center of the optical axis, and the light intensity decreases from the optical axis center to the periphery. In the present embodiment, the light receiving element coupling surface 63 is provided in the vicinity of the center of the optical axis where the intensity is strong, so that the light receiving element coupling curved surface 62 is provided in a portion away from the optical axis as in the first embodiment. Compared with the case of the case, the area of the reflecting surface for reflecting the light of the same intensity can be reduced. For this reason, in this embodiment, as shown in FIG. 15, the light beam traveling from the light receiving element coupling surface 63 to the light receiving element 32 can be made thinner than the first embodiment. Thereby, the light receiving element 32 having a smaller area can be used, and the miniaturization can be realized. Further, when the light receiving element 32 having the same area as that of the first embodiment is used, positioning accuracy when mounting the light receiving element 32 may be low, so that the optical multiplexer / demultiplexer can be easily assembled. Can do.

  In the present embodiment, the light receiving element coupling surface 63 is configured from a curved surface, but may be configured from a flat surface.

  The present invention can be applied to an optical module such as an optical multiplexer / demultiplexer.

It is an exploded view showing the configuration of the optical multiplexer / demultiplexer of the present invention. It is a perspective view which shows the structure of the optical multiplexer / demultiplexer of this invention. It is the II sectional view taken on the line of FIG. (A) is a perspective view which shows the structure of a main block, (b) is principal part sectional drawing. It is a perspective view which shows the structure of a fiber unit. (A) is a top view which shows the structure of a light receiving element block, (b) is a side view. (A) is a top view which shows the structure of a waveguide mirror block, (b) is a side view. (A) is a top view which shows the structure of a filter block, (b) is a top view of the surface on the opposite side to (a), (c) is a side view. It is a perspective view explaining typically operation of an optical multiplexer / demultiplexer. It is a top view which illustrates typically operation | movement of an optical multiplexer / demultiplexer. It is a figure which illustrates typically the operation | movement in case an optical multiplexer / demultiplexer functions as a splitter. It is a figure which illustrates typically operation in case an optical multiplexer / demultiplexer functions as a multiplexer. It is a perspective view which shows the modification of a main block. It is a perspective image for demonstrating the modification of a concave mirror. It is a figure which illustrates typically operation in case an optical multiplexer / demultiplexer functions as a multiplexer. It is an exploded view which shows the structure of the conventional optical multiplexer / demultiplexer. It is a top view which shows the structure of the conventional optical multiplexer / demultiplexer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Main block, 2 ... Fiber unit, 3 ... Light receiving element block, 4 ... Waveguide mirror block, 5 ... Filter block, 6 ... Concave mirror, 7 ... Holding plate, 11 ... Base part, 12a, 12b, 12c ... Side wall, DESCRIPTION OF SYMBOLS 13 ... Plane part, 14 ... Groove formation part, 14a ... Groove, 15 ... Gap part, 16 ... Fiber unit mounting part, 16a ... Recessed part, 17 ... Mirror block holding part, 17a ... Projection, 18 ... Filter block holding part, 18a ... Projection 19. Light receiving element block holding portion 19 a. Flat surface 19 b. Projection portion 21. Lower holding substrate 22. Upper holding substrate 23 Optical fiber 31 Light receiving element mounting substrate 31 a Lower surface 31 b Upper surface, 32 ... light receiving element, 33 ... electrical connector, 41 ... support part, 41a ... mirror surface, 41b ... adhesive face, 42 ... reflection element, 43 ... projection, 51 ... support part, 5 ... light branching element, 53 ... hole, 61 ... fiber coupling curved surface, 62 ... light-receiving element binding curved surface, 63 ... light-receiving element coupling surfaces.

Claims (1)

A reflective condensing element composed of a concave mirror and reflecting light incident from a first direction in a second direction;
A beam splitter disposed on the optical axis of either the first direction or the second direction and transmitting or reflecting light according to the wavelength;
A reflective member that is formed at a substantially central portion of the mirror of the reflective condensing element and reflects a part of the light incident on the reflective condensing element in a third direction;
A light receiving element for detecting the power of the light reflected by the reflecting member ,
An optical fiber is disposed on the optical axis of the first direction and the second direction where the beam splitter is not disposed,
The reflection condensing element functions as an optical fiber coupling element that couples a light beam incident or emitted from an end face of the optical fiber and a light beam passing through the light beam branching element;
The optical multiplexer / demultiplexer, wherein the reflecting member is formed of a reflecting surface protruding from the mirror of the reflective condensing element and having a different angle from the mirror .