JP2003282896A - Light transmitting and receiving module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent noises caused by electrostatic and electromagnetic inductions which are generated from the light emitting side of a light transmitting and receiving module to its light receiving side when mounting its light emitting element and its light receiving element in a single package. <P>SOLUTION: With respect to the light transmitting and receiving module, a metal thin film is so formed on an optical plate used in it as to reduce the influence of the electrostatic or electromagnetic induction generated from its light emitting side to its light receiving side. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transmission / reception module applied to an optical transmission / reception device or an optical medium recording device for performing bidirectional communication using one optical fiber for transmission and reception.

[0002]

2. Description of the Related Art With the progress of optical communication systems, there has been an increasing demand for miniaturization of optical transmission / reception modules which are headends of optical communication systems. In the optical communication system, the magnitudes of the signal voltage and the signal current used in the transmitter are significantly larger than those in the receiver. Therefore, if the optical transceiver module is downsized, the influence of electrostatic induction or electromagnetic induction from the transmitter to the receiver becomes stronger. Especially, the influence is great in the optical transceiver module in which the light emitting element and the light receiving element are arranged on the same substrate.

FIG. 7 shows the configuration of a conventional optical transceiver module used in an optical communication system. In FIG. 7, 12 is a received signal light, 13 is an optical plate, 14 is a transmitted signal light, 15 is a light emitting element, 30 is a substrate, and 31 is an optical plate. In the one-core bidirectional transmission method in which transmission and reception are performed by using one optical fiber, an optical transceiver module in which a light emitting element 15 used for transmission and a light receiving element 13 used for reception are mounted on the same substrate 30 Used. A part of the received signal light 12 from the optical medium (not shown) is transmitted through the optical plate 31, and the light receiving element 1
Light is received at 3. A part of the transmission signal light 14 from the light emitting element 15 is reflected by the optical plate 31 and is coupled to an optical medium (not shown).

In the configuration of the conventional optical transmitter / receiver module, the signal voltage and signal current used in the light emitting element are much higher than those used in the light receiving element. Therefore, the light receiving element is electrostatically or electromagnetically induced from the light emitting element. Was propagated to and caused noise.

In the one-core bidirectional transmission system, the same wavelength is used for the upstream signal light and the downstream signal light, and the optical signal plate such as a half mirror is used for the upstream signal light and the downstream signal light in the single core. The same-wavelength single-core bidirectional transmission method in which bidirectional transmission is performed with an optical fiber, and different wavelengths are used for the upstream signal light and the downstream signal light. There is a different wavelength single-core bidirectional transmission system in which bidirectional transmission is performed with a single-core optical fiber. In the recording method for the optical recording medium, the light for reading and the reflected light from the optical recording medium have the same wavelength, so the same wavelength single-core bidirectional transmission that uses the same wavelength for the upstream signal light and the downstream signal light It will be similar to the method.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical transceiver module capable of reducing the influence of electrostatic induction or electromagnetic induction from a transmitter to a receiver in order to solve such a problem. And

[0007]

In order to achieve the above-mentioned object, in the invention according to claim 1, all or a part of received signal light from an optical medium is provided on a substrate on which a light emitting element and a light receiving element are mounted. A light transmitting / receiving module comprising an optical plate that transmits or reflects light to enter a light receiving element, and reflects or transmits all or part of transmission signal light from the light emitting element to transmit to the optical medium, A metal thin film was formed on the optical plate, and the metal thin film was electrically connected to the substrate. Claim 1
According to the invention of claim 1, it is possible to prevent electrostatic induction by interposing a metal thin film between the light emitting element and the light receiving element.

According to a second aspect of the present invention, in the first aspect, the metal thin film is formed thick in a portion other than the portion where the received signal light illuminates the optical plate so that the transmitted signal light can be blocked. According to the invention of claim 2, the metal thin film is formed thick to effectively prevent electrostatic induction.

According to a third aspect of the present invention, all or a part of the received signal light from the optical medium is transmitted or reflected on the substrate on which the light emitting element and the light receiving element are mounted to enter the light receiving element. An optical transmission / reception module comprising an optical plate that reflects or transmits all or part of transmission signal light from an element and transmits the signal light to the optical medium, wherein a thin film of a metal having a high magnetic permeability is formed on the optical plate. According to the invention of claim 3, a metal thin film having a high magnetic permeability is interposed between the light emitting element and the light receiving element to prevent electromagnetic induction.

According to a fourth aspect of the present invention, in the third aspect, a metal thin film having a high magnetic permeability is formed in a portion other than the portion where the received signal light irradiates the optical plate so as to block the transmitted signal light. . According to the invention of claim 4, the thick metal thin film effectively prevents the electromagnetic induction.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the first invention of the present application will be described below with reference to the accompanying drawings. (Embodiment 1) FIG. 1 shows a schematic configuration of an optical transceiver module according to the present invention. A feature of the present embodiment is that it is applied to the one-core bidirectional transmission system, and therefore has a structure that prevents electrostatic induction from the light emitting element from affecting the light receiving element. Less than,
It will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing the structure of an optical transmitter / receiver module applied to the one-core bidirectional transmission system. In FIG. 1, 10 is a substrate, 11 is an optical plate, 12 is received signal light,
13 is a light receiving element, 14 is a transmission signal light, 15 is a light emitting element,
20 is a metal thin film. Received signal light 12 from an optical medium (not shown) passes through the optical plate 11 and is received by the light receiving element 13 installed on the substrate 10. The transmission signal light 14 from the light emitting element 15 installed on the substrate 10 is reflected by the optical plate 11 and travels toward the optical medium (not shown). In this state,
Since the light emitting element 15 is driven by a high frequency signal of several V, a large noise is generated in the light receiving element due to electrostatic induction from the vicinity of the light emitting element.

Therefore, the metal thin film 20 is vapor-deposited on the optical plate 11, and the metal thin film 20 is electrically connected to the substrate 10. As described above, if the metal thin film formed on the optical plate is conducted to the substrate, the influence of electrostatic induction from the light emitting element can be reduced, and as a result, noise due to electrostatic induction can be reduced. . The means for forming the metal thin film may be a means for attaching the metal thin film to the optical plate 11 other than vapor deposition.

As a material of the metal thin film 20, a metal having high conductivity is desirable. For example, gold, silver, copper, nickel, aluminum, etc. are suitable. Alternatively, ITO (indium tin oxide) or the like used for the transparent electrode may be used. In this case, electrostatic induction can be prevented while ensuring transparency.

In the different-wavelength single-core bidirectional transmission system, a wavelength filter that transmits a specific wavelength or reflects a specific wavelength is applied to the optical plate. In this case, the transmittance of the metal thin film is preferably 70% or more at the wavelength used. In the same-wavelength single-core bidirectional transmission method, a half mirror that transmits and reflects at a fixed ratio is applied to the optical plate. A metal thin film that prevents electrostatic induction can also function as a half mirror. When the metal thin film functions as a half mirror, the transmittance of the metal thin film is 30% or more and 70% or more.
The following are preferred.

In the present embodiment, the transmission signal light 14 from the light emitting element 15 is reflected by the optical plate 11 and coupled to the optical medium (not shown), and the reception signal light 1 from the optical medium (not shown) 1
2 is configured to pass through the optical plate 11 and enter the light receiving element 13, but the transmitted signal light from the light emitting element passes through the optical plate and is coupled to the optical medium, and the received signal light from the optical medium is Even if the optical plate reflects light and enters the light receiving element, a metal thin film capable of preventing electrostatic induction is formed on the optical plate to form the substrate 10.
The effect of preventing electrostatic induction can be obtained by connecting to.

(Second Embodiment) In the first embodiment, the metal thin film for preventing electrostatic induction is uniformly formed on the optical plate.
In this embodiment, a more effective metal thin film is formed.
FIG. 2 shows how the transmission signal light and the reception signal light respectively illuminate the optical plate. In FIG. 2, 16 is an optical medium and 17 is a coupling lens. As shown in FIG.
The transmission signal light 14 from the normal light emitting element 15 is emitted from the optical medium 1
The received signal light 12 from 6 illuminates the optical plate 26 more widely than it illuminates the optical plate 26.

Therefore, as shown in FIGS. 3 (a), 3 (b) and 3 (c), a metal thin film having a thickness that can block the transmission signal light is formed on the outer edge of the optical plate. 3A shows a metal thin film 21 formed on the upper and lower portions of the optical plate, and FIG. 3B shows a metal thin film 22 on the left and right portions of the optical plate.
FIG. 3C shows a case where the metal thin film 23 is formed on the optical plate while leaving the elliptical shape. This is an example in which a metal thin film having a thickness that can block transmission signal light is formed. The transmittance of the transmission signal light in the metal thin films 21, 22 or 23 is preferably 1% or less. Thus, by forming the metal thin film thick, electrostatic induction can be effectively blocked. As a material for the metal thin films 21, 22 or 23, a metal having high conductivity is desirable. For example,
Gold, silver, copper, nickel, aluminum and the like are preferable.

In order to make the portion where the metal thin film having such a thickness as to block the transmission signal light is formed more effective, FIG.
As shown in (a), if a metal thin film having a thickness that can block the transmission signal light is formed while leaving the range in which the reception signal light from the optical medium irradiates the optical plate 11, it is possible to effectively electrostatically discharge. The influence of induction can be reduced. At this time, the signal light received from the optical medium irradiates the optical plate 11 with a substantially elliptical shape, as shown in FIG. 4B. In addition, in addition to forming the metal thin film in the first embodiment, the transmission signal light is further formed in the shape shown in FIG. 3 (a), (b), (c) or FIG. 4 (b) shown in the present embodiment. The influence of electrostatic induction can be reduced more effectively by forming a metal thin film having a thickness capable of blocking.

As described above, if a metal thin film is formed in a specific portion of the optical plate to a thickness such that transmission signal light can be blocked and the metal thin film and the substrate are electrically connected to each other, it is possible to effectively keep static electricity. The influence of electric induction can be reduced, and the noise caused by electrostatic induction can be reduced.

(Embodiment 3) FIG. 5 shows a schematic configuration of an optical transceiver module according to the present invention. A feature of the present embodiment is that it is applied to the one-core bidirectional transmission system, and therefore has a structure for preventing noise caused by electromagnetic induction from the light emitting element affecting the light receiving element. Hereinafter, it will be described in detail with reference to the drawings.

FIG. 5 is a sectional view showing the structure of an optical transceiver module applied to the one-core bidirectional transmission system. In FIG. 5, 25 is a metal thin film. Received signal light 12 from an optical medium (not shown) passes through the optical plate 11 and is received by the light receiving element 13 installed on the substrate 10. The transmission signal 14 from the light emitting element 15 installed on the substrate 10 is reflected by the optical plate 11 and travels to the optical medium (not shown). In this state, the light emitting element 15 is driven by a high frequency signal of several tens of mA, so that large noise is generated in the light receiving element due to electromagnetic induction from the vicinity of the light emitting element.

Therefore, the metal thin film 25 is formed on the optical plate 11 with a metal having high magnetic permeability. In this way, if the light emitting element and the light receiving element are cut off by the metal thin film formed on the optical plate, the magnetic lines of force from the vicinity of the light emitting element flow through the metal thin film, and the influence of electromagnetic induction on the light receiving element is reduced. The noise due to electromagnetic induction can be reduced. As the metal having high magnetic permeability, iron, nickel, cobalt, and amorphous metals thereof can be applied. Alternatively, ITO (indium tin oxide) used as a transparent electrode may be used. In this case, electrostatic induction can be prevented while ensuring transparency.

In the different-wavelength single-core bidirectional transmission system, a wavelength filter that transmits a specific wavelength or reflects a specific wavelength is applied to the optical plate. In this case, the transmittance of the metal thin film is preferably 70% or more at the wavelength used. In the same-wavelength single-core bidirectional transmission method, a half mirror that transmits and reflects at a fixed ratio is applied to the optical plate. A metal thin film that prevents electromagnetic induction can also function as a half mirror. The transmittance of the metal thin film in this case is 3
It is preferably 0% or more and 70% or less.

In the present embodiment, the transmitted signal light 14 from the light emitting element 15 is reflected by the optical plate 11 and coupled to the optical medium (not shown), and the received signal light 1 from the optical medium (not shown) 1 is received.
2 is configured to pass through the optical plate 11 and enter the light receiving element 13, but the transmitted signal light from the light emitting element passes through the optical plate and is coupled to the optical medium, and the received signal light from the optical medium is Even if it is configured to reflect on the optical plate and enter the light receiving element, if a metal thin film that can prevent electromagnetic induction is formed on the optical plate,
An electromagnetic induction prevention effect can be obtained.

(Embodiment 4) In Embodiment 3, the metal thin film for preventing electromagnetic induction is uniformly formed on the optical plate.
In this embodiment, a more effective metal thin film is formed.
As described with reference to FIG. 2, the transmission signal light 14 from the normal light emitting element 15 illuminates the optical plate more widely than the reception signal light 12 from the optical medium 16 illuminates the optical plate 26.

Therefore, as shown in FIGS. 3 (a), 3 (b) and 3 (c), a metal thin film having a thickness that can block the transmission signal light is formed on the outer edge of the optical plate. 3A shows a metal thin film 21 formed on the upper and lower portions of the optical plate, and FIG. 3B shows a metal thin film 22 on the left and right portions of the optical plate.
FIG. 3C shows a case where the metal thin film 23 is formed on the optical plate while leaving the elliptical shape. This is an example in which a metal thin film having a thickness that can block transmission signal light is formed. The transmittance of the transmission signal light in the metal thin films 21, 22 or 23 is preferably 1% or less. By thus forming the metal thin film thick, it is possible to effectively block electromagnetic induction.

In order to make more effective the portion where the metal thin film having a thickness that can block the transmission signal light is made more effective, as shown in FIG. 6, the reception signal light from the optical medium irradiates the optical plate 11. If the metal thin film 25 having a thickness that can block the transmission signal light is formed while leaving the range, the influence of electromagnetic induction can be effectively reduced. At this time, the shape of the signal light received from the optical medium that irradiates the optical plate 11 is substantially elliptical. In addition, in addition to forming a thin film of a metal having a high magnetic permeability in the third embodiment, the thin film shown in FIG.
The influence of electromagnetic induction can be reduced more effectively by forming a thin film in the shape of (b), (c) or FIG. 6 with a metal that is thick enough to block transmission signal light.

As described above, if the metal thin film is formed in a specific portion of the optical plate with a thickness that can block the transmission signal light, the influence of electromagnetic induction can be effectively reduced. Noise due to electromagnetic induction can be reduced.

[0030]

As described above, according to the present invention, it is possible to effectively reduce the influence of electrostatic induction or electromagnetic induction from the light emitting element provided on the same substrate to the light receiving element. Noise to the light receiving element can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an optical transceiver module showing an embodiment of the first invention of the present application.

FIG. 2 is a schematic diagram illustrating the operation of the second invention of the present application.

FIG. 3 is a schematic diagram showing a configuration of an optical plate of a second invention of the present application.

FIG. 4 is a schematic diagram illustrating the operation of the second invention of the present application.

FIG. 5 is a configuration diagram of an optical transceiver module showing an embodiment of the third invention of the present application.

FIG. 6 is a schematic diagram illustrating the operation of the fourth invention of the present application.

FIG. 7 is a configuration diagram of a conventional optical transceiver module.

[Explanation of symbols]

10: substrate 11: Optical plate 12: Received signal light 13: Light receiving element 14: Transmission signal light 15: Light emitting element 16: Optical medium 17: Combined lens 20, 21, 22, 23, 24, 25: Metal thin film 26: Optical plate 30: substrate 31: Optical plate

Continued front page    F term (reference) 2H037 AA01 BA03 BA12 CA37 DA40                 2K009 CC14 EE00                 5E321 BB23 GG01 GG05 GH01                 5F073 AB27 AB28 AB29 BA02 EA27                 5F088 AA01 BA16 BA20 BB01 EA09                       EA13 JA03 JA12 JA14 JA16

Claims (4)

[Claims] 1. A transmission signal light from the light emitting element while transmitting or reflecting all or part of the reception signal light from the optical medium onto the light receiving element on a substrate on which the light emitting element and the light receiving element are mounted. An optical transmission / reception module comprising an optical plate for transmitting or transmitting all or part of the above to the optical medium, wherein a metal thin film is formed on the optical plate, and the metal thin film and the substrate are electrically connected. A featured optical transceiver module. 2. The optical transceiver module according to claim 1, wherein a metal thin film is formed thick in a portion other than a portion where the received signal light irradiates the optical plate so that the transmitted signal light can be blocked. 3. A substrate on which a light emitting element and a light receiving element are mounted transmits or reflects all or part of received signal light from an optical medium to enter the light receiving element and transmit signal light from the light emitting element. Is an optical transmission / reception module including an optical plate for reflecting or transmitting all or a part of the optical transmission to the optical medium, wherein the optical plate is formed with a thin film of a metal having a high magnetic permeability. . 4. The light according to claim 3, wherein a metal thin film having a high magnetic permeability is formed thick in a portion other than a portion where the received signal light irradiates the optical plate so as to block the transmitted signal light. Transmit / receive module.