JP2006030463A - Optical module, optical signal transmitter and optical transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mall optical module having a simple constitution, and to provide an optical signal transmitter and an optical transmitter. <P>SOLUTION: An optical module 12 is provided with a VCSEL34 and a PD36 which are mounted on a first rigid substrate (a circuit substrate) and a light guiding rod 38 which optically couples the VCSEL34 and a transmitting optical fiber 44. Moreover, the optical module 12 is provided with a receptacle section 24 which covers the light guiding rod 38, the VCSEL34 and the PD36 and no lens is used to optically couple the VCSEL34 and the optical fiber 44. Therefore, the optical module having a simple constitution is realized. Since there is no need to actively align lenses, the production process is simplified and the production cost of the optical module 12 is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical module to which an optical fiber is connected, an optical signal transmission device, and an optical transmission device.

  Along with the broadbandization of information communication services, there is a demand for an increase in transmission capacity. As one of the solutions, optical communication is widely performed. In optical communication, an optical signal transmission device is used in which a light emitting element, a light receiving element, and a board on which electronic components electrically connected thereto are mounted and packaged in a casing (for example, Patent Documents 1 to 4). reference).

  In addition, the optical transmitter and the optical receiver of the optical signal transmission device have a subassembly including a light emitting element or a light receiving element and a lens system in order to optically couple the light emitting element, the light receiving element, and the optical fiber with high accuracy. . For example, Patent Documents 2 and 4 disclose subassemblies in which a laser diode and a ball lens are held in a case.

  By the way, as an optical fiber for long-distance communication, an SM (single mode) type or MM (multi mode) type optical fiber in which the core of the optical fiber is made of quartz has been conventionally used.

  On the other hand, in recent years, POF (plastic optical fiber) and HPCF (hard polymer clad fiber), which have a diameter larger than that of quartz fiber, have come to be used in homes and optical transmission at a relatively short distance. Note that the core diameter of the quartz fiber is about 62.5 μm at the largest.

  FIGS. 7 and 8 show examples of subassemblies of an optical signal transmission apparatus using POF. In FIG. 7, VCSEL (surface emitting laser) 84 is used as a light emitting element, and PD (pin photodiode) 86 having a light receiving diameter of 0.1 mmφ is used as a light receiving element. Also, as the transmission optical fiber 94 and the reception optical fiber 96, POF having a fiber diameter of 0.5 mmφ is used. In this example, the transmission optical fiber 94 and the VCSEL 84, and the reception optical fiber 96 and the PD 86 are optically coupled by lenses 88 and 92, respectively.

  VCSEL 84 and PD 86 are mounted on a common substrate (not shown).

  In addition, it is necessary to align the interface position of a device (not shown) in which the optical signal transmission device 80 is incorporated (that is, the device housing and the external connection surface such as a connector are matched). For this reason, in the receptacle part 104 which comprises the optical signal transmission apparatus 80, the connection part 108 for transmission to which the optical fiber 94 for transmission is connected, and the connection part 110 for reception to which the optical fiber 96 for reception is connected. The positions are aligned, that is, the external connection surfaces are coincident. The position of the interface of a device (not shown) incorporating the optical signal transmission device 80 is also aligned.

  In the conventional optical signal transmission device 80, the light receiving diameter of the PD 86 is smaller than the fiber diameter of the optical fiber 96. For this reason, a condensing lens 92 is required to optically couple the optical fiber 96 and the PD 86. Further, since the light emitting surface of the VCSEL 84 and the transmission optical fiber 94 are largely separated from each other, a condensing lens 88 is used.

In addition, the VCSEL 84 and the PD 86 are fixed in the lens barrel by being actively aligned (that is, fixed at a position having the highest coupling efficiency by moving the package).
JP 2001-298217 A JP 2000-155251 A JP 2002-82261 A JP 7-151943 A

  Incidentally, in recent years, there has been a demand for further downsizing of optical signal transmission devices. In addition, when the coupling lenses 88 and 92 are used, there is a problem that high position mounting accuracy is required and that the manufacturing process becomes complicated due to active alignment, thereby increasing the manufacturing cost.

  In view of the above facts, an object of the present invention is to provide an optical module, an optical signal transmission device, and an optical transmission device that have a simple configuration and are miniaturized.

  The inventor has intensively studied the miniaturization of the optical signal transmission device. As a result, instead of the conventional quartz optical fiber, when using a large-diameter optical fiber such as POF or HPCF as described above, if it is possible to reduce the distance between the VCSEL and the transmission optical fiber, It has been found that optical coupling is possible without using a lens, and the present invention has been completed.

  According to the first aspect of the present invention, at least one of optical coupling between the light emitting element and the optical fiber for transmitting the optical signal and optical coupling between the light receiving element and the optical fiber for receiving the optical signal are performed. An optical module for transmitting and receiving: a light emitting element, a light receiving element, an optical coupling between the light emitting element and the transmitting optical fiber, and an optical coupling between the light receiving element and the transmitting optical fiber. A light guide rod that performs at least one of the light guide rod and a receptacle that covers the light guide rod, the light receiving element, and the light emitting element.

  In this specification, optical coupling means enabling optical transmission.

  In the first aspect of the invention, a lens for optical coupling is not used. Therefore, an optical module with a simple configuration is realized. In addition, since there is no need to actively align the lenses, the manufacturing process can be simplified and the manufacturing cost of the optical module can be reduced. Furthermore, the optical module can be miniaturized by shortening the length of the light guide rod.

  These effects are particularly noticeable when a transmission optical fiber having a large diameter is used.

  The invention according to claim 2 is an optical module that optically couples a light emitting element, an optical fiber for transmitting an optical signal, and a light receiving element and an optical fiber for receiving an optical signal, and transmits and receives signals. A light guide rod for optically coupling the light emitting device, the light receiving device, the light emitting device and the optical fiber for transmission, and a receptacle for covering the light guide rod, the light receiving device, and the light emitting device. It is characterized by providing.

  In this mode, the light receiving area is relatively small on the receiving side, and the receiving module having a lens for coupling signal light from the optical fiber to the light receiving element is combined with the transmitting module not using the lens for optical coupling on the transmitting side. To do. As a result, when the signal light from the optical fiber is directly received, the utilization efficiency can be improved in the configuration where the light reception efficiency is insufficient, and the configuration on the transmission side is simple, realizing a low-cost optical module. Is done.

  According to a third aspect of the present invention, the light receiving element and the light emitting element are provided on one surface of a circuit board, and the receptacle portion includes a transmission connection portion to which the transmission optical fiber is connected, and the reception portion. A receiving connection portion to which an optical fiber is connected, and the transmission connecting portion and the receiving connection portion are provided on one surface.

  Thereby, a miniaturized optical module having a simple configuration and having end faces (connection faces) of the optical fibers for transmission and reception located in the same plane is realized.

  The invention described in claim 4 is characterized in that the diameter D1 of the light guide rod is 100 μm or more.

  As a result, it is possible to optically couple with the element without performing special alignment such as active alignment, and the assembly cost can be reduced.

  The invention described in claim 5 is characterized in that the light guide rod is formed of an optical fiber.

  This makes it possible to produce an optical module at low cost by using a commercially available fiber that does not require a new lens design or new processing.

A sixth aspect of the present invention is an optical signal transmission device comprising the optical module according to any one of the first to fifth aspects, the transmission optical fiber, and the reception optical fiber. Thus, a miniaturized optical signal transmission apparatus is realized.

  The invention according to claim 7 is characterized in that the transmission optical fiber is a plastic optical fiber (POF) or a hard polymer clad fiber (HPCF).

  Thereby, even if an optical fiber having a relatively large diameter and easily available is used, the durability is good.

  The invention according to an eighth aspect is characterized in that the aperture D1 of the light guide rod and the core aperture D2 of the optical fiber for transmission satisfy a relationship of D1 ≦ D2.

  Thereby, the light emitted so as to spread from the end face of the light guide rod efficiently enters the optical fiber for transmission.

  According to a ninth aspect of the present invention, the light guide rod is formed of an optical fiber, and the numerical aperture NA1 of the optical fiber and the numerical aperture NA2 of the optical fiber for transmission satisfy a relationship of NA1 ≦ NA2. It is characterized by.

  Thereby, the signal light (propagation mode) transmitted with the optical fiber used for the light guide rod can be efficiently guided to the transmission optical fiber.

  A tenth aspect of the present invention includes the optical module according to any one of the first to fifth aspects, the transmission optical fiber, and the reception optical fiber. .

  As a result, signal transmission between bases relatively distant from each other is possible, and an inexpensive optical transmission device can be constructed.

  Since the present invention has the above-described configuration, an optical module, an optical signal transmission device, and an optical transmission device that are simple and downsized are realized.

  Hereinafter, embodiments will be described and embodiments of the present invention will be described. In the second and subsequent embodiments, the same components as those already described are denoted by the same reference numerals and description thereof is omitted.

[First Embodiment]
First, the first embodiment will be described. As shown in FIGS. 1 to 3, the optical signal transmission device 10 of the first embodiment includes a first rigid board (circuit board) 18 on which a light emitting element module 14 and a light receiving element module 16 are mounted, and a light emitting element module. 14 and a second rigid substrate 22 on which a driving LSI for driving the light receiving element module 16 is mounted, and an FPC (flexible printed circuit) 20 for connecting the first rigid substrate 18 and the second rigid substrate 22 to each other. , A receptacle section 24 that covers the light emitting element module 14 and the light receiving element module 16, and a casing 26 that houses the first rigid board 18 and the second rigid board 22, and transmits and receives optical signals. It is.

  The light emitting element module 14 includes a VCSEL 34 provided as a light emitting element in the can package 28, and a cylindrical light guide rod 38 having a diameter D1 (see FIG. 3) of 180 μm. The light guide rod 38 is made of quartz glass having a refractive index of 1.62, and is fixed to the lens barrel 40 with a UV adhesive (NOALAND, NOA61, refractive index: 1.56).

  It is desirable that the light guide rod 38 and the window surface 28G of the can package 28 are fixed in close contact with each other. Further, in order to connect the light guide rod 38 and the window surface 28G of the can package 28, it is possible to combine them using a matching gel or matching oil in order to prevent Fresnel reflection.

  The light receiving element module 16 includes a PD (pin photodiode) 36 in the can package 30 and a lens 42 for guiding light from the optical fiber 46 to the PD 36. The light receiving diameter of the PD 36 is 0.1 mmφ.

  In the receptacle part 24, a transmission connection part 48 to which a transmission optical fiber 44 is connected and a reception connection part 50 to which a reception optical fiber 46 is connected are formed on the same plane. The end face 44E of the transmission optical fiber 44 and the end face 46E of the reception optical fiber 46 are located on the same plane. Further, light from the light guide rod 38 enters the optical fiber 44 for transmission, and incident light to the lens 42 is emitted from the optical fiber 46 for reception. In the present embodiment, GI (graded index type) HPCF (core aperture D2 (see FIG. 3): 200 μm (cladding diameter: 230 μm), NA: 0.4) is used as the optical fibers 44 and 46. These are connected to the transmission connection section 48 and the reception connection section 50 by a double SC type connector, respectively. The optical fibers 44 and 46 are not limited to GI (graded index type) HPCF, but may be SI (step index type) HPCF, SI POF, or GI POF.

  In the present embodiment, the optical module 12 that performs optical coupling between the transmission optical fiber 44 and the VCSEL 34 and optical coupling between the reception optical fiber 46 and the PD 36 is provided in the receptacle unit 24 and the receptacle unit 24. Light guide rod 38 and lens 42.

  As described above, according to the present embodiment, as the optical fibers 44 and 46, the HPCF having a relatively large diameter and being easily available and having good durability are used, and the VCSEL 34 provided as a light emitting element and the light for transmission are used. The fiber 44 is optically coupled with the light guide rod 38, and no lens is used as in the prior art. Therefore, the optical signal transmission device 10 including the optical module 12 having a simple configuration is realized. In addition, since it is not necessary to actively align the lenses, the manufacturing process of the optical module 12 can be simplified, and the manufacturing cost of the optical module 12 can be reduced.

  The light guide rod 38 is not limited to quartz glass, but can also be a refractive index distribution type glass (cell hook lens). Further, the light emitting element is not limited to the VCSEL 34, and an end surface light emitting type laser diode or a light emitting diode can also be used. Further, the package of the light emitting element is not limited to the can package, and a resin sealed package may be used.

  The end of the light guide rod 38 may be formed in a convex lens shape. By using the convex lens shape, the spread angle of the light emitted from the end of the light guide rod 38 can be reduced, and the coupling efficiency between the light guide rod 38 and the light emitting element or the light guide rod 38 and the optical fiber 44 can be further increased. It becomes possible to improve.

[Second Embodiment]
Next, a second embodiment will be described. As shown in FIG. 4, the present embodiment is different from the first embodiment in that the light guide rod that optically couples the transmission optical fiber 44 and the VCSEL 34 is formed of a cylindrical optical fiber. In this embodiment, an optical module 62 that performs optical coupling between the transmission optical fiber 44 and the VCSEL 34 and optical coupling between the reception optical fiber 46 and the PD 36 is provided in the receptacle 54 and the receptacle 54. Light guide rod 58 and lens 42.

  In this embodiment, the POF (CK-10, NA: 0.5, core diameter: 240 μm (cladding diameter: 250 μm)) manufactured by Mitsubishi Rayon is used as the light guide rod 58, and the optical fibers 44 and 46 connected from the outside are used. A POF (GH-2001, NA: 0.5, core diameter: 480 μm (cladding diameter: 500 μm)) manufactured by Mitsubishi Rayon is used, and is connected to the optical module 62 by a double SC type connector.

In the present embodiment, the numerical aperture NA1 of the optical fiber used as the light guide rod 58 and the numerical aperture NA2 of the transmission optical fiber 44 are:
NA1 ≤ NA2
Meet the relationship. Thereby, the signal light (propagation mode) transmitted with the optical fiber used for the light guide rod can be efficiently guided to the transmission optical fiber.

  In this embodiment, an optical fiber that is not coated with fiber is used as the light guide rod 58. It should be noted that an optical fiber with a fiber coating can be used even if the coating thickness varies widely as long as the required amount of light can be transmitted.

  The optical fiber used as the light guide rod 58 is not limited to the SI-type POF but may be a GI-type POF or HPCF.

  As described above, in this embodiment, the POF is used as the light guide rod 58, which makes it possible to reduce the cost by using a commercially available fiber that does not require a new lens design or new processing. A simple optical module can be manufactured.

[Third Embodiment]
Next, a third embodiment will be described. As shown in FIG. 5, the third embodiment includes a light guide rod 72 that optically couples the receiving optical fiber 46 and the PD 36 in place of the lens 42 as compared with the first embodiment. In the present embodiment, the light guide rod 72 is composed of an optical fiber. In the present embodiment, the diameter of the light receiving region of the PD 36 is larger than that of the first embodiment, so that the light can be efficiently coupled even when the spread angle of the light emitted from the end surface 72E of the light guide rod 72 is large. ing.

  It is desirable that the light guide rod 72 and the window surface 30G of the can package 30 are fixed in close contact with each other. Further, in order to connect the light guide rod 72 and the window surface 30G of the can package 30, it is also possible to use a matching gel or a matching oil in order to prevent Fresnel reflection.

  In this embodiment, an optical module 73 that performs optical coupling between the transmission optical fiber 44 and the VCSEL 34 and optical coupling between the reception optical fiber 46 and the PD 36 is provided in the receptacle unit 74 and the receptacle unit 74. The light guide rod 58 and the light guide rod 72 are formed.

  Thus, in the present embodiment, the PD 36 and the receiving optical fiber 46 are optically coupled by the light guide rod 72, and no lens is used as in the prior art. Therefore, compared with the first embodiment, an optical module having a simple configuration and a reduced size is realized.

[Fourth Embodiment]
Next, a fourth embodiment will be described. FIG. 6 is a schematic diagram showing an example of a system in which an optical transmission device 75 equipped with an optical module according to the present invention is used.

  As shown in FIG. 6, this system includes floor optical switches 76A to 76F provided on each floor, a backbone optical switch 77 serving as a backbone thereof, a backbone optical switch 77, and floor optical switches 76A to F, respectively. Optical fibers 78A to 78F to be connected. A plurality of information terminals are connected to each of the floor optical switches 76A to 76F.

  The optical transmission device 75 includes a backbone optical switch 77, floor optical switches 76A to 76F, optical fibers 78A to F, and the information terminals described above, and the optical module of the present invention is mounted on the optical transmission device 75. .

  Such a system is applicable not only to a general office network, but also to a hospital network, a network of residents such as condominiums, and a campus network such as a university.

  According to this embodiment, high-speed optical transmission is possible, and construction of an inexpensive optical transmission system is realized.

  The embodiments of the present invention have been described above with reference to the embodiments. However, these embodiments are merely examples, and various modifications can be made without departing from the scope of the invention. Needless to say, the scope of rights of the present invention is not limited to the above embodiment.

It is an expansion perspective view of the optical signal transmission device of a 1st embodiment. It is a typical plane sectional view showing the composition which transmits the light from a light emitting element to an optical fiber with the optical module which constitutes the optical signal transmission device of a 1st embodiment. It is an optical module which constitutes the optical signal transmission device of a 1st embodiment, and is a typical plane sectional view showing that the diameter of a light guide rod is thinner than the diameter of an optical fiber. It is a typical plane sectional view showing the composition which transmits the light from a light emitting element to an optical fiber with the optical module which constitutes the optical signal transmission device of a 2nd embodiment. It is a typical plane sectional view showing the composition which transmits the light from an optical fiber to a photo acceptance unit by the optical module which constitutes the optical signal transmission device of a 3rd embodiment. It is an example of the system demonstrated by 4th Embodiment, and is a schematic diagram which shows an example of the system which has an optical transmission apparatus carrying the optical module of this invention. It is a typical plane sectional view showing the composition of the conventional optical signal transmission device. It is a typical plane sectional view showing the composition of the conventional optical signal transmission device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical signal transmission apparatus 12 Optical module 18 1st rigid board (circuit board)
24 Receptacle part 34 VCSEL (light emitting device)
36 PD (light receiving element)
38 Light guide rod 44 Transmission optical fiber 44E End face 46 Reception optical fiber 46E End face 48 Transmission connection section 50 Reception connection section 54 Receptacle section 58 Light guide rod 62 Optical module 72 Light guide rod 73 Optical module 74 Receptacle section 75 Optical Transmission Devices 78A-F Optical Fiber 80 Optical Signal Transmission Device 84 VCSEL (Light Emitting Element)
86 PD (light receiving element)
94 Transmission Optical Fiber 94E End Face 96 Reception Optical Fiber 96E End Face 104 Receptacle

Claims (10)

An optical module that transmits and receives signals by performing at least one of optical coupling between a light emitting element and an optical fiber for transmitting an optical signal and optical coupling between a light receiving element and an optical fiber for receiving an optical signal. ,
A light emitting element;
A light receiving element;
A light guide rod that performs at least one of optical coupling between the light emitting element and the transmission optical fiber, and optical coupling between the light receiving element and the transmission optical fiber;
A receptacle for covering the light guide rod, the light receiving element, and the light emitting element;
An optical module comprising: An optical module that optically couples a light emitting element and an optical fiber for transmitting an optical signal, and a light receiving element and an optical fiber for receiving an optical signal, respectively, and transmits and receives signals.
The light emitting element;
The light receiving element;
A light guide rod for optically coupling the light emitting element and the transmission optical fiber;
A receptacle that covers the light guide rod, the light receiving element, and the light emitting element;
An optical module comprising: The light receiving element and the light emitting element are provided on one surface of a circuit board,
The receptacle unit includes a transmission connection unit to which the transmission optical fiber is connected, and a reception connection unit to which the reception optical fiber is connected,
The optical module according to claim 1, wherein the transmission connection unit and the reception connection unit are provided on one surface.   The optical module according to any one of claims 1 to 3, wherein a diameter D1 of the light guide rod is 100 µm or more.   The optical module according to any one of claims 1 to 4, wherein the light guide rod is formed of an optical fiber. An optical module according to any one of claims 1 to 5,
The transmitting optical fiber;
The receiving optical fiber;
An optical signal transmission device comprising:   The optical signal transmission device according to claim 6, wherein the transmission optical fiber is a plastic optical fiber or a hard polymer clad fiber. The diameter D1 of the light guide rod and the core diameter D2 of the optical fiber for transmission are:
D1 ≤ D2
The optical signal transmission device according to claim 6, wherein the relationship is satisfied. The light guide rod is composed of an optical fiber, and the numerical aperture NA1 of the optical fiber and the numerical aperture NA2 of the optical fiber for transmission are:
NA1 ≤ NA2
The optical signal transmission device according to claim 6, wherein the relationship is satisfied. An optical module according to any one of claims 1 to 5,
The transmitting optical fiber;
The receiving optical fiber;
An optical transmission device comprising:

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