JP2005345674A - Optical composite module and light wavelength multiplexed transmission system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an optical compound module, in which coupling functions among light input-output ends and a light-emitting element/a light-receiving element and an optical multiplexer/demultiplexer can be integrated with simple constitution, and to realize, by using the same, a light wavelength multiplexed transmission system whose constitution is simple. <P>SOLUTION: In the optical composite module, since it becomes possible to receive an optical signal being a part of optical signals transmitting a 1st optical fiber 104 with a light-receiving element 106 by demultiplexing it and also it becomes possible to transmit an optical signal from a light-emitting element 107, and it becomes possible to transmit the optical signal from an optical fiber 105, while multiplexing it by providing 1st and 2nd convergent rod lenses 101, 102 so as to hold a 1st optical filter 103 and by providing the 1st and 2nd optical fibers 104, 105 at the side of the 1st convergent rod lens 101 and by providing the light-receiving element 106 and the light-emitting element 107 at the side of the 2nd convergent rod lens 102, coupling functions among the optical fibers and the light-emitting element/the light-receiving element and the optical multiplexer/demultiplexer can be integrated using a simple constitution. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical wavelength division multiplexing transmission system for optical wavelength division multiplexing transmission of a plurality of information signals and the like, and more particularly to an optical composite module used therefor, and more specifically, an optical demultiplexing / multiplexing function and light receiving and emitting. The present invention relates to an optical composite module having a function of coupling an element and an optical fiber.

  In order to expand the optical fiber transmission capacity, an optical wavelength division multiplexing transmission system that transmits optical signals of different wavelengths by wavelength multiplexing is used. Among optical wavelength division multiplex transmission systems, there is a system in which a master station device and a plurality of slave station devices are connected in cascade with an optical fiber (see, for example, Patent Document 1). FIG. 9 shows a conventional optical wavelength division multiplexing transmission system described in Patent Document 1. In FIG. FIG. 10 shows a demultiplexing / multiplexing unit of the conventional optical wavelength division multiplexing transmission system described in Patent Document 1.

In FIG. 9, the master station device 28 and the plurality of slave station devices 29 to 32 are connected in cascade by optical fibers. Each of the slave station devices 29 to 32 has the optical demultiplexing unit shown in FIG. The optical signal of the fiber 37 was received by demultiplexing the optical signal of wavelength λ1 to the fiber 39 by the lens systems 41 and 43 and the optical filter 45. Further, the transmission signal having the wavelength λ 1 is multiplexed from the fiber 38 by the lens systems 42 and 44 and the optical filter 45 and transmitted by the fiber 40. In the slave station devices 29 to 32, the transmission wavelength band of the optical filter is changed, and optical wavelength multiplexing transmission is performed.
Japanese Patent Publication No. 60-57777 (page 2-3, FIG. 3, FIG. 4)

  However, the conventional configuration requires a large number of lens systems, and a light receiving module (not shown) that couples the fiber 39 and the light receiving element separately from FIG. 10 or a light emitting module that couples the light emitting element and the fiber 38 (not shown). (Not shown in the figure) is required, which complicates the configuration and hinders cost reduction. In addition, since the reception optical signal demultiplexed to the fiber 39 and the transmission optical signal multiplexed from the fiber 38 have the same wavelength, and the reflectance at the wavelength λ1 of the optical filter 45 cannot be completely zero, the light from the fiber 38 Since a part of the signal is reflected by the optical filter and coupled to the fiber 39, there is a problem that the near-end leakage becomes large.

  The present invention solves the above-mentioned conventional problems. An optical composite module capable of reducing the near-end leakage to an extremely low level and capable of reducing the near-end leakage to a very low level, and an optical wavelength multiplex transmission using the same. The purpose is to provide a system.

  In order to solve the above-described conventional problems, an optical composite module according to a first aspect of the present invention includes a first optical filter and first and second lenses arranged substantially coaxially with the first optical filter interposed therebetween. And an imaging point of the first light input / output end by a lens system comprising the first and second light input / output ends disposed in the vicinity of the focal plane of the first lens and the first and second lenses A light receiving element provided in the vicinity, and a light emitting element provided in the vicinity of an image forming point of the second light input / output end by the lens system including the first and second lenses, and the first optical filter comprises: The reflected wavelength emitted from the first light input / output end is characterized by providing a transmission wavelength band that transmits in the vicinity of the emission wavelength band of the light emitting element and a reflection wavelength band that reflects a part of the other wavelength band. The band light is converted into substantially parallel light by the first lens, Is reflected by the serial first optical filter is characterized in that again placing the second light input and output ends are condensed in a position to form an image in said first lens.

  According to the first aspect, the coupling function between the light input / output terminal and the light emitting element / light receiving element and the optical multiplexer / demultiplexer can be integrated with a simple configuration.

  An optical composite module according to a second invention is an invention dependent on the first invention, wherein the first and second light input / output ends are substantially aligned with respect to the optical axis of the first lens. It is characterized by being arranged in a symmetrical position.

  According to the second aspect, the lens can be easily aligned and fixed.

  Furthermore, an optical composite module according to a third aspect of the invention is an invention dependent on the first or second aspect, wherein the first and second optical input / output ends are respectively connected to the first and second optical fibers. It features an end face.

  According to the third aspect of the invention, the coupling function of the optical fiber and the light emitting element / light receiving element and the optical multiplexer / demultiplexer can be integrated with a simple configuration.

  An optical composite module according to a fourth aspect of the invention is an invention dependent on the third aspect of the invention, wherein the first and second optical fibers are arranged substantially parallel to each other.

  According to the fourth aspect, the two optical fibers can be easily fixed.

  The optical composite module according to a fifth aspect of the present invention is an invention dependent on any one of the first to fourth aspects, wherein the first and second lenses are convergent rod lenses. Yes.

  According to the fifth aspect, it is possible to easily fix the lens and another optical component.

  An optical composite module according to a sixth invention is an invention dependent on the fifth invention, wherein the first and second lenses and the first optical filter are arranged in close contact with each other. It is a feature.

  According to the sixth aspect, the lens and the optical filter can be easily fixed.

  Furthermore, the optical composite module according to a seventh aspect of the present invention is the first optical path, the first optical filter disposed at an angle other than a right angle with respect to the first optical path, and the first optical filter with respect to the first optical filter. A second optical path provided at a position that is a reflection position from the first optical path, a light receiving element provided at a position that is a transmission position from the first optical path with respect to the first optical filter, and the first optical path A demultiplexing characteristic comprising a light emitting element provided at a position that is a transmission position from the second optical path with respect to the optical filter, and a second optical filter provided between the first optical filter and the light receiving element. The first optical filter has a characteristic that a specific wavelength band including an emission wavelength of the light emitting element is a transmission wavelength band, and a part of the other wavelength band is a reflection wavelength band, The second optical filter includes the first optical filter. A wavelength band that does not include the emission wavelength of the light emitting element within the transmission wavelength band of the data is a transmission wavelength band, and a wavelength band near the emission wavelength of the light emitting element is a reflection wavelength band or an absorption wavelength band. It is said.

  According to the seventh aspect, it is possible to reduce near-end leakage in which a transmission optical signal from the light emitting element leaks into the light receiving element.

  An optical composite module according to an eighth aspect of the invention is an invention dependent on any one of the first to sixth aspects, wherein a second optical filter is provided between the second lens and the light receiving element, The second optical filter has a wavelength band that does not include the emission wavelength of the light emitting element within the transmission wavelength band of the first optical filter as a transmission wavelength band, and a wavelength band near the emission wavelength of the light emitting element is a reflection wavelength. It is characterized by having a band or absorption wavelength band.

  According to the eighth aspect of the invention, the coupling function between the light input / output terminal and the light emitting element / light receiving element, and the optical multiplexer / demultiplexer can be integrated with a simple configuration, and the transmission light signal from the light emitting element is transmitted to the light receiving element. It is possible to reduce near-end leakage.

  Furthermore, an optical composite module according to a ninth aspect is the invention according to any one of the first to sixth aspects or the eighth aspect, wherein the light emitting element and the light receiving element are the same base material or an integrated body. It is mounted on a plurality of substrates fixed and fixed, and an axis adjustment section is provided between the substrate and the second lens.

  According to the ninth aspect, the light emitting element and the light receiving element can be aligned at the same time, and the manufacturing process can be simplified.

  An optical wavelength division multiplex transmission system according to a tenth aspect of the invention is an invention dependent on any one of the first to ninth aspects, wherein a plurality of slave station devices are sequentially connected in cascade with a transmission optical fiber. In the multiplex transmission system, the plurality of slave station devices use the optical composite module according to any one of the first to ninth inventions in which the transmission wavelength bands of the first optical filter are different from each other. An optical signal transmitted through a fiber in a transmission wavelength band of the first optical filter is received by the light receiving element, and an optical signal from the light emitting element is transmitted by the transmission optical fiber.

  According to the tenth aspect of the present invention, optical wavelength division multiplex transmission can be performed with a simple slave station configuration in which the coupling function between the light input / output terminal and the light emitting element / light receiving element and the optical multiplexer / demultiplexer are integrated.

  According to the optical composite module of the present invention and the optical wavelength division multiplexing transmission system using the same, the coupling function between the light input / output terminal and the light emitting element / light receiving element and the optical multiplexer / demultiplexer are integrated with a simple configuration, and the near end It is possible to realize an optical composite module and an optical wavelength multiplexing transmission system with little leakage.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
1 and 2 are a perspective sectional view and a plan sectional view of an optical composite module 100 according to Embodiment 1 of the present invention. In FIGS. 1 and 2, the first and second convergent rod lenses 101 and 102 are fixed so as to sandwich the first optical filter 103. In the first embodiment, the first convergent rod lens has a pitch of approximately 0.25, and the second convergent rod lens is shorter than 0.25 pitch (for example, 0.2 pitch). The first optical filter is designed to transmit light in the first specific wavelength range and reflect light in other wavelength ranges other than the first specific wavelength range. For example, the first optical filter is formed on a transparent member such as glass. It can be manufactured by a method such as forming a dielectric multilayer film.

  First and second optical fibers 104 and 105 are fixed on the first converging rod lens 101 side. On the other hand, a light receiving element 106 and a light emitting element 107 are fixed on the second rod lens side. The light receiving element 106 is an element that converts an optical signal into an electric signal, such as a semiconductor light receiving element. The light emitting element 107 is an element that converts an electrical signal into an optical signal using, for example, a semiconductor laser. 1 and 2 also show the second optical filter 108, which will be described later.

  The first and second convergent rod lenses 101 and 102 are fixed to the lens fixing member 201. The first and second optical fibers 104 and 105 are fixed to the fiber fixing member 202. The light receiving element 106 and the light emitting element 107 are fixed to the light receiving element table 203 and the light emitting element table 204, respectively, and the light receiving element table 203 and the light emitting element table 204 are fixed. The optical element stem 205 is fixed to the optical element fixing ring 206.

  The lens fixing member 201 and the fiber fixing member 202 adjust the positions of the first convergent rod lens 101 and the first and second optical fibers 104 and 105 and are fixed via the fiber adjusting member 207. The lens fixing member 201 and the optical element fixing ring 206 adjust the positions of the second convergent rod lens 102, the light receiving element 106, and the light emitting element 107, and are fixed via the optical element adjusting member 208. .

  Next, the positional relationship between the components will be described. In FIG. 1 and FIG. 2, the optical path is indicated by a two-dot chain line. The light emitted from the first optical fiber 104 into the first converging rod lens 101 is converted into substantially parallel light by the converging rod lens and reaches the first optical filter 103. The first optical filter 103 reflects light in a wavelength range other than the first specific wavelength range as described above. The reflected light is collected near the end face of the first lens, and the first converging rod lens 101 and the first and second optical fibers 105 are positioned so that the second optical fiber 105 is located near the condensing position. The positions of the optical fibers 104 and 105 are adjusted. On the other hand, the light in the first specific wavelength range that has passed through the first optical filter 103 is condensed outside the second convergent rod lens 102 by the second convergent rod lens 102. The light receiving element 106 is fixed at this condensing position. The light emitting element 107 emits light at a wavelength within the first transmission wavelength range of the first optical filter. The emitted light is converted into substantially parallel light by the second converging rod lens 102, passes through the first optical filter 103, and is collected at the end face position of the second optical fiber 105 by the first converging rod lens. A light emitting element 107 is arranged so as to be illuminated.

  Next, the operation of the first embodiment of the present invention will be described. FIG. 3 is a characteristic diagram of the first optical filter transmission wavelength region, and shows an example thereof. FIG. 3 also shows the characteristics of the transmission wavelength region of the second optical filter 108, which will be described later.

  For example, a case where light having four wavelengths λ2 to λ5 is used will be described. The transmission characteristics of the first optical filter 103 are indicated by thick solid lines in FIG. 3, and the first specific wavelength region including λ3 and λ4 is the transmission region. Light in a wavelength range other than the first specific wavelength range including λ2 and λ5 is reflected. Therefore, when optical signals having wavelengths λ2, λ3, and λ5 are transmitted to the first optical fiber 104 and emitted to the first convergent rod lens 101, the light having the wavelengths λ2 and λ5 outside the first specific wavelength range is the first. Reflected by one optical filter 103. Light having wavelengths λ <b> 2 and λ <b> 5 enters the second optical fiber 105 and is transmitted through the second optical fiber 105. On the other hand, light having a wavelength of λ3 in the first specific wavelength range is incident on the light receiving element 106 and converted into an electrical signal. This electrical signal is taken out through a receiving terminal 301 provided in the optical element stem 205. The light receiving element 106 and the receiving terminal 301 are connected by a wire or the like, but are not shown. The light emitting element 107 converts the electrical signal input from the transmission terminal 302 into an optical signal having a wavelength λ4 and emits the optical signal toward the second convergence rod lens 102. The optical signal having the wavelength λ4 is collected near the end face of the second optical fiber 105 and incident, and is transmitted along with the light having the wavelengths λ2 and λ5 through the second optical fiber 105. That is, an optical signal having a part of the wavelength of the optical signal transmitted through the first optical fiber 104 is demultiplexed and converted into an electrical signal by the light receiving element 106, and the electrical signal applied to the light emitting element 107 is converted into an optical signal. The function of converting the signal into a signal, combining it, and sending it out from the optical fiber 105 is obtained.

  As described above, according to such a configuration, the first and second convergent rod lenses 101 and 102 are provided so as to sandwich the first optical filter 103, and the first convergent rod lens 101 side has the first. And the second optical fibers 104 and 105, and by providing the light receiving element 106 and the light emitting element 107 on the second converging rod lens 102 side, one of the optical signals transmitted through the first optical fiber 104 is provided. The optical signal of the wavelength of the light is demultiplexed and converted into an electric signal by the light receiving element 106, and the electric signal applied to the light emitting element 107 is converted into an optical signal, multiplexed, and transmitted from the second optical fiber 105. Therefore, an optical composite module having both a function of coupling an optical fiber and a light emitting element / light receiving element and an optical multiplexing / demultiplexing function can be realized with a simple configuration.

  In the first embodiment of the present invention, the first and second convergent rod lenses 101 and 102 are fixed to the lens fixing member 201. However, this is one design example, for example, The first convergent rod lens 101 is fixed to the lens fixing member 201, the second convergent rod lens 102 is fixed to the end surface of the first convergent rod lens 101 via the first optical filter 103, etc. The present invention is not limited to the detailed design.

  In the first embodiment of the present invention, the first optical filter 103 is manufactured by a method such as forming a dielectric multilayer film on a transparent member such as glass, but the first converging rod lens 101 is used. Alternatively, it may be formed by a method such as forming a dielectric multilayer film directly on the end face of the second convergent rod lens 102.

  Next, the second optical filter 108 will be described. As described above, all of the light emitted from the light emitting element 107 ideally passes through the first optical filter 103. However, in practice, it is difficult to make the reflectance at the wavelength λ4 of the optical filter 103 zero, and some of the light is reflected. The reflected light having the wavelength λ4 is collected near the light receiving element 106 in the same manner as the light having λ3. For this reason, near-end leakage that causes the light receiving element 106 to receive the transmission signal from the light emitting element 107 occurs. In order to prevent this problem, the second optical filter 108 is provided. The second optical filter 108 has the transmission characteristics shown in FIG. 3, and transmits light in the second specific wavelength region near λ3. The second specific wavelength region is set narrower than the first specific wavelength region that is the transmission region of the first optical filter 103. The second optical filter 108 has a characteristic of reflecting or absorbing light in a wavelength region including λ4 outside the second specific wavelength region. As a result, it is possible to prevent a part of the light of λ4 reflected by the first optical filter 103 from entering the light receiving element 106. Similarly to the first optical filter 103, the second optical filter 108 can be manufactured by a method such as forming a dielectric multilayer film on a transparent member such as glass. Similarly to the first optical filter 103, it is also possible to form a dielectric multilayer film directly on the end face of the second converging rod lens 102.

  As described above, according to the first embodiment of the present invention, the second optical filter 108 is provided between the second convergent rod lens 102 and the light receiving element 106, whereby the transmission signal from the light emitting element 107 is obtained. Can be prevented from leaking into the light receiving element 106.

  In Embodiment 1 of the present invention, the second optical filter 108 is set close to the second convergent rod lens 102, but like the optical composite module 1100 shown in FIG. The second optical filter 1108 is provided on the optical path between the second convergent rod lens 102 and the light receiving element 106, for example, the second optical filter 1108 is fixed to the optical element case 209 installed on the optical element stem 205. Thus, the same effect can be obtained.

  In FIG. 1, FIG. 2, and FIG. 4, the second optical filters 108 and 1108 are installed substantially at right angles to the optical path, but may be installed inclined to prevent reflected return light.

  Next, the position adjustment of the light receiving element 106 and the light emitting element 107 will be described. When the positions of the light receiving element 106 and the light emitting element 107 are adjusted after the first and second converging rod lenses 101 and 102 and the first and second optical fibers 104 and 105 are positioned and fixed, the light receiving element 106 The allowable position accuracy is about one digit larger than the allowable position accuracy of the light emitting element 107. For example, the allowable position accuracy of the light emitting element 107 is often about several μm or 1 μm or less, and the allowable position accuracy of the light receiving element 106 is often about several tens μm. On the other hand, when the light receiving element 106 and the light emitting element 107 are mounted on the light receiving element base 203 and the light emitting element base 204 on the optical element stem 205, the interval between the light receiving element 106 and the light emitting element 107 must be mounted with an accuracy within several tens of μm. Is possible. Therefore, first, the light receiving element 106 and the light emitting element 107 are fixed on the optical element stem 205, the light receiving element table 203, and the light emitting element table 204, which are integrally fixed, with an accuracy within several tens of μm. Next, while monitoring the power of the optical signal from the light emitting element 107 incident on the second optical fiber, the position is adjusted and fixed with respect to the second convergent rod lens 102, so that the light receiving element 106 The position can also be adjusted. In Embodiment 1 of the present invention, optical element adjustment is performed by adjusting the position between the lens fixing member 201 to which the second converging rod lens 102 is fixed and the optical element fixing ring 206 to which the optical element stem 205 is fixed. It can be fixed by the member 208.

  As described above, according to such a configuration, after the light receiving element 106 and the light emitting element 107 are integrally fixed, the light receiving element 106 and the light emitting element are aligned and fixed with the convergent rod lens 102. 107 can be adjusted and fixed at the same time.

  FIG. 5 is a plan sectional view of another optical composite module 2100 according to Embodiment 1 of the present invention. The main difference from the first embodiment shown in FIGS. 1 and 2 is that the first and second convex lenses 2101 and 2102 are used instead of the first and second convergent rod lenses 101 and 102. That is. Accordingly, the first optical filter 2103 and the first and second convex lenses 2101 and 2102 are fixed to the lens fixing member 2201, and the second optical filter 2108 is provided on the lens surface of the second convex lens 2102. It has been. In the first embodiment of the present invention shown in FIG. 1 and FIG. 2, the convergent rod lenses 101 and 102 are used. However, even if a convex lens other than the convergent rod lens is used as in the configuration of FIG. An effect is obtained.

(Embodiment 2)
FIG. 6 is a perspective view of the optical composite module 4100 according to Embodiment 2 of the present invention. FIG. 7 is a side cross-sectional view taken along the alternate long and short dash line in FIG. 6 and 7, the optical waveguide substrate 4110 is composed of X-shaped optical waveguides 4111a to 4111d formed of a clad 4112 and a core material. The optical waveguide substrate 4110 is provided with first and second optical fibers 4104 and 4105, a light receiving element 4106, and a light emitting element 4107 on the end face where the optical waveguides 4111 a to 4111 d are exposed. In addition, a first optical filter 4103 and a second optical filter 4108 are inserted into the optical waveguide substrate 4110 so as to face the optical waveguides 4111a to 4111d. Similar to the first optical filter 103 and the second optical filter 108 in Embodiment 1, the first optical filter 4103 and the second optical filter 4108 have the characteristics shown in FIG.

  Next, the operation of the second embodiment of the present invention will be described. When optical signals having wavelengths λ2, λ3, and λ5 are transmitted from the first optical fiber 4104 and are incident on the first optical waveguide 4111a, the light having the wavelengths λ2 and λ5 is reflected by the first optical filter 4103. Light of wavelengths λ2 and λ5 propagates through the optical waveguide 4111b, enters the second optical fiber 4105, and is transmitted through the second optical fiber 4105. On the other hand, the light of wavelength λ3 propagates through the waveguide 4111c, enters the light receiving element 4106, and is converted into an electrical signal. In addition, the light emitting element 4107 converts the input electric signal into an optical signal having a wavelength λ4 and outputs the optical signal to the waveguide 4111d. The optical signal having the wavelength λ4 propagates through the waveguides 4111d and 4111b and is transmitted along with the light having the wavelengths λ2 and λ5 through the second optical fiber 4105. That is, an optical signal having a part of the wavelength of the optical signal transmitted through the first optical fiber 4104 is demultiplexed and converted into an electric signal by the light receiving element 4106, and the electric signal applied to the light emitting element 4107 is converted into an optical signal. The function of converting the signal into a signal, combining it, and sending it out from the optical fiber 4105 is obtained. In addition, since the first optical filter 4103 cannot have a reflectivity with respect to light within the transmission wavelength range, a part of the optical signal having the wavelength λ4 from the light emitting element 4107 is reflected by the first optical filter 4103 and guided. Although propagating through the waveguide 4111c, since the second optical filter 4108 is provided, it is possible to prevent the optical signal having the wavelength λ4 from entering the light receiving element 4106 and to prevent near-end leakage.

  As described above, according to such a configuration, the first and second optical fibers 4104 and 4105, the light receiving element 4106, and the light emitting element 4107 are provided on the end faces of the X-shaped optical waveguides 4111a to 4111d, and the first optical fiber is provided. By inserting the filter 4103 and the second optical filter 4108 so as to face the optical waveguides 4111a to 4111d, an optical signal having a part of the wavelength of the optical signal transmitted through the first optical fiber 4104 is separated. The light is converted into an electric signal by the light receiving element 4106, and the electric signal applied to the light emitting element 4107 is converted into an optical signal to be combined and sent out from the optical fiber 4105. Leakage can be suppressed, and an optical composite module having both a coupling function between an optical fiber and a light emitting element / light receiving element and an optical multiplexing / demultiplexing function can be realized.

  In FIG. 6, the second optical filter 4108 is installed at a substantially right angle to the optical waveguide 4111c, but may be installed at an angle to prevent reflected return light.

(Embodiment 3)
FIG. 8 is a configuration diagram of an optical wavelength division multiplex transmission system according to Embodiment 3 of the present invention. In FIG. 8, a master station device 5301 and slave station devices 5302a to 5302c of the optical wavelength division multiplexing transmission system 5000 are connected in cascade by optical fibers 5305a to 5305d. The master station device 5301 includes three electric / optical converters 5310 to 5312 that convert electric signals into optical signals with different wavelengths λ1, λ3, and λ5, and an optical multiplexer 5313 that combines the light with λ1, λ3, and λ5. An optical demultiplexer 5314 that demultiplexes the wavelength-multiplexed optical signals with wavelengths λ2, λ4, and λ6 into optical signals with wavelengths λ2, λ4, and λ6, and optical signals with wavelengths λ2, λ4, and λ6 that are demultiplexed, respectively. Are made up of three optical / electrical converters 5315 to 5317 for converting the signals into electrical signals. Here, the wavelengths λ1 to λ6 are shown as an example of the wavelength arrangement shown in FIG. The slave station devices 5302a to 5302c respectively receive electrical signals from the optical composite modules 5100a to 5100c having the same configuration as any of the optical composite modules 100, 1100, and 2100 in the first embodiment, and the light receiving elements of the optical composite modules 5100a to 5100c. Optical receiving circuits 5321a to 5321c that receive and amplify, etc., and optical transmission circuits 5322a to 5322c that drive the light emitting elements by inputting electric signals to the optical composite modules 5100a to 5100c. However, the optical composite modules 5100a to 5100c have different characteristics of built-in optical filters.

  The first optical filter 103 (or 2103) of the optical composite module 5100a has characteristics that include λ1 and λ2 in the transmission wavelength region and include λ3 to λ6 in the reflection wavelength region. The second optical filter 108 (or 1108 or 2108) of the optical composite module 5100a has a characteristic that λ1 is included in the transmission wavelength region and λ2 is not included in the transmission wavelength region.

  The first optical filter 103 (or 2103) of the optical composite module 5100b has characteristics that include λ3 and λ4 in the transmission wavelength region and include λ1, λ2, λ5, and λ6 in the reflection wavelength region. The second optical filter 108 (or 1108 or 2108) of the optical composite module 5100b has a characteristic that λ3 is included in the transmission wavelength region and λ4 is not included in the transmission wavelength region. That is, the optical composite module 5100b includes an optical filter having the characteristics shown in FIG.

  The first optical filter 103 (or 2103) of the optical composite module 5100c has characteristics that include λ5 and λ6 in the transmission wavelength region and include λ1 to λ4 in the reflection wavelength region. The second optical filter 108 (or 1108 or 2108) of the optical composite module 5100a has a characteristic that λ5 is included in the transmission wavelength region and λ6 is not included in the transmission wavelength region.

  Next, the operation of the third embodiment configured as described above will be described. Optical signals of different wavelengths λ1, λ3, and λ5 converted from the master station device 5301 by the electrical / optical converters 5310 to 5312 and directed to the slave station devices 5302a to 5302c are combined by the optical combiner 5313 and the optical fiber. Sent to 5305a. When the optical composite module 5100a of the slave station device 5302a is, for example, the optical composite module 100 shown in FIG. 1, the optical fiber 5305a is the first optical fiber 104 in FIG. 1, and the optical fiber 5305b is the second optical in FIG. It is connected to the fiber 105. Therefore, the optical composite module 5100a demultiplexes only the optical signal of wavelength λ1 for the slave station 5302a out of the optical signals of wavelengths λ1, λ3, and λ5, converts the optical signal into an electrical signal, and amplifies the signal by the optical receiving circuit 5321a. Do. The slave station device 5302a inputs a signal for the master station device 5301 from the optical transmission circuit 5322a to the optical composite module 5100a, converts it to an optical signal of wavelength λ2, multiplexes it to the optical fiber 5305b, and transmits it. Therefore, the optical fiber 5305b is wavelength-multiplexed with the optical signal having the wavelength λ1 from the slave station device 5302a to the master station device 5301 and the optical signals having the wavelengths λ3 and λ5 from the master station device 5301 to the slave station devices 5302b and 5302c. A signal is transmitted. Similarly, the slave station devices 5302b and 5302c transmit and receive signals. The master station device 5301 receives wavelength multiplexed optical signals of wavelengths λ2, λ4, and λ6 from the slave station devices 5302a to 5302c through the optical fiber 5305d. Entered. An optical demultiplexer 5314 demultiplexes the optical signals with wavelengths λ2, λ4, and λ6, and optical / electrical converters 5315 to 5317 respectively extract signals from the slave station apparatuses 5302a to 5302c as electric signals. In this manner, signals can be transmitted bidirectionally independently between the master station device 5301 and the slave station devices 5302a to 5302c.

  Further, by providing the optical composite modules 5100a to 5100c used in the slave station devices 5302a to 5302c with the second optical filter 108, 1108, or 2108 shown in FIG. 1, FIG. 4, and FIG. It is possible to prevent leakage into a signal and to perform bidirectional optical wavelength division multiplexing transmission with little near-end leakage.

  As described above, according to the third embodiment of the present invention, by using the optical composite modules 5100a to 5100c in the slave station devices 5100a to 5100c, the optical signal that performs bidirectional signal transmission with the master station device with a simple configuration. A wavelength division multiplexing transmission system is realized.

  Further, according to Embodiment 3 of the present invention, by providing the second optical filter 108, 1108, or 2108 in the optical composite modules 5100a to 5100c, a bidirectional optical wavelength division multiplexing transmission system with little near-end leakage is obtained. Realize.

  In the optical composite module according to the present invention, the coupling function of the light input / output terminal and the light emitting element / light receiving element, and the optical multiplexer / demultiplexer can be integrated with a simple configuration, and the near-end leakage can be suppressed low. It is useful for applications such as an optical transmission system for wavelength-multiplexing transmission of a plurality of optical signals. In addition, the optical wavelength division multiplexing transmission system using this optical composite module is capable of wavelength multiplexing transmission of a plurality of optical signals with a simple configuration and suppressing near-end leakage, and information transmission systems such as data transmission, video transmission, and audio signal transmission. It can be applied to other uses.

1 is a perspective cross-sectional view showing a configuration of an optical composite module according to Embodiment 1 of the present invention. Plan sectional drawing which shows the structure of the optical composite module in Embodiment 1 of this invention Characteristic diagram of optical filter used in Embodiment 1 of the present invention Plan sectional drawing which shows the structure of the other optical composite module in Embodiment 1 of this invention. Plan sectional drawing which shows the structure of the other optical composite module in Embodiment 1 of this invention. The perspective view which shows the structure of the optical composite module in Embodiment 2 of this invention. Side surface sectional drawing which shows the structure of the optical composite module in Embodiment 2 of this invention. Configuration diagram of optical wavelength division multiplexing transmission system in Embodiment 3 of the present invention Configuration of conventional optical wavelength division multiplexing transmission system Configuration diagram showing demultiplexing / multiplexing unit of conventional optical wavelength division multiplexing transmission system

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Optical composite module 101 1st convergence rod lens 102 2nd convergence rod lens 103 1st optical filter 104 1st optical fiber 105 2nd optical fiber 106 Light receiving element 107 Light emitting element 108 2nd optical filter DESCRIPTION OF SYMBOLS 201 Lens fixing member 202 Fiber fixing member 203 Light receiving element stand 204 Light emitting element stand 205 Optical element stem 206 Optical element fixing ring 207 Fiber adjusting member 208 Optical element adjusting member 301 Reception terminal 302 Transmission terminal 1100 Optical composite module 1108 Second optical filter 2100 Optical composite module 2101 1st convex lens 2102 2nd convex lens 2103 1st optical filter 2108 2nd optical filter 2201 Lens fixing member 4100 Optical composite module 4103 1st optical filter 4104 First optical fiber 4105 Second optical fiber 4106 Light receiving element 4107 Light emitting element 4108 Second optical filter 4110 Optical waveguide substrate 4111a, 4111b, 4111c, 4111d Optical waveguide 4112 Cladding 5000 Optical wavelength division multiplexing system 5100a, 5100b, 5100c Optical composite module 5301 Master station apparatus 5302a, 5302b, 5302c Slave station apparatus 5305a, 5305b, 5305c, 5305d Optical fiber 5310, 5311, 5312 Electric / optical converter 5313 Optical multiplexer 5314 Optical demultiplexer 5315, 5316, 5317 Optical / Electrical converters 5321a, 5321b, 5321c Optical receiver circuits 5322a, 5322b, 5322c Optical transmitter circuits

Claims (10)

A first optical filter;
First and second lenses disposed substantially coaxially with the first optical filter interposed therebetween;
First and second light input / output terminals disposed near the focal plane of the first lens;
A light receiving element provided in the vicinity of an imaging point of the first light input / output end by a lens system including the first and second lenses;
A light emitting element provided in the vicinity of an image forming point of the second light input / output end by a lens system including the first and second lenses,
The first optical filter has a characteristic of a transmission wavelength band that transmits near the emission wavelength band of the light emitting element, and a reflection wavelength band that reflects a part of the other wavelength band,
The reflected wavelength band light emitted from the first light input / output end is converted into substantially parallel light by the first lens, reflected by the first optical filter, and collected again by the first lens. An optical composite module in which the second light input / output end is disposed at a position where the light is imaged. The first and second light input / output ends are arranged at positions substantially symmetrical with respect to the optical axis of the first lens.
The optical composite module according to claim 1. The first and second light input / output ends are the end faces of the first and second optical fibers, respectively.
The optical composite module according to claim 1 or 2. The first and second optical fibers are arranged substantially parallel to each other;
The optical composite module according to claim 3. The first and second lenses are convergent rod lenses,
The optical composite module according to any one of claims 1 to 4. The first and second lenses and the first optical filter are arranged in close contact with each other.
The optical composite module according to claim 5. A first optical path;
A first optical filter disposed at an angle other than a right angle to the first optical path;
A second optical path provided at a position to be a reflection position from the first optical path with respect to the first optical filter;
A light receiving element provided at a position to be a transmission position from the first optical path with respect to the first optical filter;
A light emitting element provided at a position to be a transmission position from the second optical path with respect to the first optical filter;
An optical composite part having a demultiplexing characteristic composed of a second optical filter provided between the first optical filter and the light receiving element,
The first optical filter has a characteristic that a specific wavelength band including an emission wavelength of the light emitting element is a transmission wavelength band, and a part of other wavelength bands is a reflection wavelength band,
The second optical filter has a wavelength band that does not include the emission wavelength of the light emitting element within the transmission wavelength band of the first optical filter as a transmission wavelength band, and a wavelength band near the emission wavelength of the light emitting element is a reflection wavelength. An optical composite module characterized by having a band or absorption wavelength band. A second optical filter is provided between the second lens and the light receiving element, and the second optical filter does not include a light emission wavelength of the light emitting element within a transmission wavelength band of the first optical filter. 7. The characteristic according to claim 1, wherein a band is a transmission wavelength band, and a wavelength band near the emission wavelength of the light emitting element is a reflection wavelength band or an absorption wavelength band. Optical composite module. The light emitting element and the light receiving element are mounted on the same base material or a plurality of integrally fixed base materials, and an axis adjustment unit is provided between the base material and the second lens.
The optical composite module according to claim 1, or the optical composite module according to claim 8. 2. An optical wavelength division multiplex transmission system in which a plurality of slave station devices are connected in cascade using transmission optical fibers, wherein the transmission wavelength bands of the first optical filters are different from each other in the plurality of slave station devices. The optical composite module according to any one of claims 9 to 9, wherein the light receiving element receives an optical signal in a transmission wavelength band of the first optical filter transmitted by the transmission optical fiber, and the light emission An optical wavelength division multiplexing transmission system for transmitting an optical signal from an element through the transmission optical fiber.

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