JPH11237535A - Optical transmitter/receiver and optical transmitting/ receiving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical transmitter/receiver and an optical transmission/ reception method capable of preventing the generation of crosstalk at the time of executing optical transmission/reception and improving the efficiency of optical transmission/reception. SOLUTION: The optical transmitter/receiver is provided with a light emitting means 2 for emitting a 1st optical signal S1, an optical device 20 for making the 1st optical signal S1 emitted from the means 2 incident upon the incident end of an optical fiber 11 along a direction different from the exiting direction of a 2nd optical signal S2 from the end part 11a of the fiber 11 and a light receiving means 5 for receiving the 2nd optical signal S2 exiting from the end part 11a of the fiber 11. When the 1st optical signal S1 is made incident upon the end part 11a of the fiber 11, the means 5 is arranged on the outside of an arriving area of reflected light generated by reflecting the signal S1 on the end part 11a of the fiber 11.

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 device and an optical transmission / reception method for single-core bidirectional optical communication.

[0002]

2. Description of the Related Art A method of transmitting a signal by optical communication has been increasingly required due to diversification of information communication. When transmitting a signal by optical communication, a single-core bidirectional communication line system using one optical fiber or a two-core bidirectional communication line system using two optical fibers is usually used. In the single-core bidirectional optical communication system, an optical transmitting / receiving device as shown in FIG. 18 is used. In the conventional optical transmission / reception device shown in FIG. 18, it is necessary to divide the optical paths for optical transmission and optical reception in order to realize single-core bidirectional optical communication. The light path for transmission is such that light emitted from the laser emission source 1002 is bent at the reflection surface 1004a of the beam splitter 1004,
This is an optical path that enters the end 1011 a of the optical fiber 1011 through the coupling lens 1003.

[0003] The receiving optical path is an optical path in which light emitted from the optical fiber 1011 is condensed by the coupling lens 1003, passes through the reflecting surface 1004 a of the beam splitter 1004, and enters the photodiode 1005. That is,
A beam splitter 1004 is used to separate transmission and reception optical paths.

[0004]

As described above, at the time of transmission, light from the laser light source 1002 is reflected by the reflection surface 1004a of the beam splitter 1004. However, when this light is reflected, some of the light is reflected by the reflection surface 1004.
a and directly enters the beam splitter 1004 as stray light 1008a. Thus, the stray light 1008a that has entered the beam splitter 1004 also enters the photodiode 1005. That is, the photodiode 1005 is connected to the ordinary optical fiber 1.
In addition to receiving the receiving light emitted from 011, stray light 1008 a as crosstalk is also received. When this stray light 1008a enters the photodiode 1005, the photodiode 105
The S / N (signal / noise) of 05 deteriorates, and the transmission distance by the optical fiber 1011 becomes short.

In another conventional example, a laser light source 1002
There is also an example in which a polarization beam splitter adapted to the oscillation polarization is used in place of the beam splitter 1004. In this case, however, since the laser light is not perfectly linearly polarized, it is possible to completely eliminate the generation of the stray light 1008a during transmission. Can not. Also, when the light emitted from the optical fiber 1011 is received by the photodiode 1005, the light is reflected by the reflection surface (mirror surface) 1004a of the beam splitter 1004, so that a part of the light for reception is transmitted to the photodiode 1005. It has not been reached and wasted. The received light reflected by the reflection surface 1004a of the beam splitter 1004 enters the laser light source 1002,
02 may have unstable oscillation characteristics. Accordingly, the present invention has been made to solve the above-mentioned problems, and to provide an optical transmitting / receiving apparatus and an optical transmitting / receiving method capable of preventing occurrence of crosstalk when performing optical transmission / reception in a single-core bidirectional optical communication circuit and improving optical transmission / reception efficiency. It is an object.

[0006]

According to the present invention, there is provided an optical fiber connected to an optical fiber used in a single-core bidirectional optical communication circuit and transmitting a first optical signal to be transmitted to the optical fiber. A light transmitting / receiving device for receiving a second optical signal transmitted through the optical fiber while being incident on an end of the optical fiber; a light emitting unit for emitting the first optical signal; Light-receiving means for receiving the second optical signal emitted from the optical fiber, the second optical signal along a direction different from the direction of emission from the end of the optical fiber,
An optical device for causing the first optical signal of the light emitting means to be incident on an incident end of the optical fiber, wherein the first optical signal is incident upon the end of the optical fiber. Is achieved by an optical transceiver in which the light receiving means is arranged outside a region where reflected light generated by reflection at the end of the optical fiber reaches.

According to the present invention, a first optical signal to be transmitted, which is connected to an optical fiber used in a single-core bidirectional optical communication circuit, is made incident on an end of the optical fiber and transmitted through the optical fiber. An optical transmitting and receiving apparatus for receiving the incoming second optical signal. The light emitting means of this optical transceiver is a
Emit an optical signal. The light receiving means receives the second optical signal emitted from the end of the optical fiber. The optical device causes the first optical signal of the light emitting means to enter the incident end of the optical fiber along a direction different from the direction in which the second optical signal exits from the end of the optical fiber. Thereby, in the optical device,
Since the first optical signal of the light emitting means is incident on the end of the optical fiber along a direction different from the direction in which the second optical signal exits from the end of the optical fiber, the optical path of the first optical signal is The optical paths of the two optical signals can be made almost completely independent.
For this reason, since a part of the first optical signal is not received by the light receiving unit together with the second optical signal, optical crosstalk (stray light) in the light receiving unit can be eliminated.
In the present invention, preferably, when the first optical signal is incident on the end of the optical fiber, the first optical signal is reflected by the end of the optical fiber, and outside the region where the reflected light reaches,
By arranging the light receiving means, it is possible to more reliably prevent the occurrence of crosstalk (stray light).

In the present invention, preferably, the optical device includes a light condensing member and a direction changing element, so that the light condensing member condenses the first optical signal of the light emitting means, and then the direction changing element condenses the first light signal. The optical path of the first optical signal can be converted into a direction different from the direction in which the second optical signal exits from the end of the optical fiber, and can be incident on the end of the optical fiber. Thus, the first optical signal of the light emitting means can be efficiently incident on the end of the optical fiber. In the present invention, preferably,
The direction changing element of the optical device sets the optical path of the first optical signal to the second path.
By providing a reflection film on the reflection surface for converting the optical signal into a direction different from the direction in which the optical signal exits from the end of the optical fiber, the first optical signal can be converted to the end of the optical fiber with a simple configuration. The light can be reliably and efficiently incident on the portion.

In the present invention, preferably, if the reflection film is a total reflection film, the first light signal can be made incident on the end of the optical fiber without loss of the light amount. In the present invention, a light emitting means, an optical device, and a package for housing the light receiving means are provided, and the optical fiber can be attached to the package so that the end of the optical fiber can be detachably attached to the light receiving means. It can be easily attached to and detached from the transmitting / receiving device. In the present invention, preferably,
If light shielding means is arranged in the package to prevent light from the light emitting means from leaking from the package, even if the optical fiber comes off the package, it is possible to prevent light from the light emitting means from leaking out of the package. Can be.

In the present invention, it is preferable to provide a light-collecting element for condensing the second optical signal and making it incident on the light receiving means, so that the efficiency of incidence of the second optical signal on the light receiving means can be increased.

[0011] The object of the present invention is to connect a first optical signal to be transmitted to an optical fiber used in a single-core bidirectional optical communication circuit and to transmit the first optical signal to an end of the optical fiber. An optical transmitting and receiving method for receiving a second optical signal transmitted through the optical fiber, wherein the second optical signal is directed in a direction different from a direction in which the second optical signal is emitted from the end of the optical fiber. The first light signal of the light emitting means is incident on the end of the optical fiber, the light receiving means receives the second light signal emitted from the end of the optical fiber, and the first light signal The optical transmission / reception method is characterized by not receiving the light reflected at the end of the optical fiber.

Thus, the first optical signal of the light emitting means is incident on the end of the optical fiber along a direction different from the direction in which the second optical signal exits from the end of the optical fiber. The optical path of the signal and the optical path of the second optical signal can be made almost completely independent. From this, since a part of the first optical signal is not received by the light receiving means together with the second optical signal, optical crosstalk (stray light) in the light receiving means can be eliminated, and Since the reflected light at the end of the optical fiber is not received, optical stock in the light receiving means can be more reliably prevented.

[0013]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limits are given, the scope of the present invention is not limited to these modes unless otherwise specified in the following description.

FIG. 1 shows an example in which a so-called connected home is connected to an information provider in the world via a network as an object to which the optical transmitting and receiving apparatus of the present invention can be applied. Various electric devices, information devices, and the like are arranged in the house 200. The house 200 provides information from an external content provider 201 to the home server 203 via the access network 202, or provides information from the home server 203 to the access network 2
The information can be sent to the content provider 201 through the communication device 02. The house 200 is provided with an antenna 204, and the content provider 201
Can be received via the artificial satellite 205. As a method of providing information, a method using terrestrial waves can be adopted.

In the house 200 shown in FIG. 1, a control system 210 for the above-described devices and a multimedia system 220 are provided. The control system 210 is a device used in a general household, for example, an electric light 210A, a refrigerator 210B, a microwave oven 210.
C, a signal path for controlling the indoor unit 210D of the air conditioner, the electric carpet 210E, the gas water heater 210F, the home medical device 210G, and the like is formed. On the other hand, the multimedia system 220 is a device corresponding to the multimedia age, such as a computer 220A, a telephone 220B, and an audio device 220.
C, portable information device 220D, digital still camera 2
20E, a printer / facsimile 220F, a digital video camera 220G, a game machine 220H, a DVD (digital versatile disk or digital video disk: trademark) player 220I, and a signal path for controlling a television receiver 220J and the like. The various devices of the control system 210 and the multimedia system 220 transmit and receive optical signals to and from the home server 203 using an optical fiber described later using a single-core bidirectional optical communication system. It can perform on / off control of each device, supply information to various devices, and perform operations such as switching on and off the television receiver 220J of the multimedia system 220, and supplying and sending information. It has become.

FIG. 2 shows an example of the optical transmission / reception apparatus 1 for connecting the home server 203 between various devices of the control system 210 or the multimedia system 220 shown in FIG. This optical transmitting and receiving apparatus is used for a so-called single-core bidirectional optical communication circuit, and the optical fiber 11 can transmit and receive an optical signal between one device M1 and the other device M2. The optical transceiver 1 is provided in each of these devices M1 and M2. These devices M1 and M2 are each device of the control system 210, each device of the multimedia system 220, the home server 203, and the like shown in FIG.

FIGS. 3 and 4 show a preferred embodiment of the optical transceiver 1 of FIG. This optical transceiver 1
Is for performing single-core bidirectional optical communication using the optical fiber 11. The end 11a of the optical fiber 11 can be removably fitted into the hole 10f of the connector 10 of the package 7 of the optical transceiver 1. This optical transceiver 1
Has a package 7, a laser light source 2 as a light emitting means, an optical device 20, a photodiode 5 as a light receiving means, and the like. The laser emission source 2 includes a semiconductor element 32
It is provided on. The laser light source 2 is, for example, a semiconductor laser that emits a laser beam L having a wavelength of 650 nm, and this laser beam L is a first optical signal S1 to be transmitted. The driving of the laser light source 2 is as follows.
This is performed by a laser light emission drive circuit (not shown), and the laser light emission drive circuit drives the laser light emission source 2 so as to generate the first optical signal S1.

The optical device 20 is arranged in an optical path between the laser light source 2 and the optical fiber 11. Optical fiber 11
Is preferably perpendicular to the optical axis OP1 of the first optical signal S1. The optical device 20 has a function of bending the optical path of the first optical signal S1 and causing the first optical signal S1 to enter the end 11a of the optical fiber 11 along the direction indicated by the arrow R1. This optical device 20
Has a coupling lens (condensing lens) 3, a base 3a, and a rising mirror 4. The base 3 a fixes the coupling lens 3, and the coupling lens 3 faces the laser light source 2. The rising mirror 4 is located behind the coupling lens 3, and the rising mirror 4 has a substantially triangular cross section and preferably has a total reflection film 4a formed on an inclined surface.

The coupling lens 3 is a convex lens that guides the first optical signal S1 of the laser light source 2 to the total reflection film 4a side of the rising mirror 4, and includes a center of the coupling lens 3 and the first optical signal S1. The intensity centers are shifted by a distance d. For this reason, the first optical signal S1 that has passed through the coupling lens 3 is condensed by the coupling lens 3, and the path of the intensity center is bent. The laser light signal S11 whose path has been bent and converged is reflected by the total reflection film 4a of the rising mirror 4 to become a light beam 8 and an end 11a of the optical fiber 11.
At an angle θ (θ is smaller than 90 °).

The above-mentioned laser light source 2, the semiconductor 32, the base 3a of the optical device 20, the rising mirror 4, and the photodiode 5 as a light receiving means described below are set on a semiconductor substrate (substrate) 6. ing. On the other hand, the second optical signal S2 emitted from the end face 11b of the optical fiber 11 in FIG. That is, the photodiode 5 is fixed so as to be embedded in the semiconductor substrate 6 at a position corresponding to the end face 11 b of the optical fiber 11.

Next, referring to FIG. 3, FIG. 4 and FIG. 5, the first optical signal S1 and the second optical signal S2 in the optical transmitting / receiving apparatus 1 will be described.
The optical transmission / reception operation using is described. The first optical signal S1 emitted from the laser light source 2 is collected by the coupling lens 3. At this time, since the intensity center of the first optical signal S1 is shifted from the center of the coupling lens 3 by the distance d, the path of the intensity center (principal ray) of the first optical signal S1 which is the emitted light is bent upward in the figure. And the total reflection film 4a of the rising mirror 4
The light beam 8 is bent by being reflected by the light, and becomes a light beam 8 in the R1 direction.

As shown in FIG. 4 and FIG.
The light flux of the optical signal S1 enters the end face 11b of the optical fiber 11 at an angle of θ. The incident light beam 8 is divided into a light beam 8 t traveling into the optical fiber 11 and an end face 11 of the optical fiber 11.
The light beam 8r reflected by b is split. When the reflected light beam 8r reaches the light receiving region of the photodiode 5, optical crosstalk (stray light) in the photodiode 5 occurs.
Reflects in the direction of arrow R2. At the end face 11b, the light beam 8r is reflected by the semiconductor substrate 6 at a reflection angle θ.
It reflects in two directions. The region that reflects and reaches the semiconductor substrate 6 is outside the light receiving region of the photodiode 5. That is, in order to avoid stray light, by selecting the position of the photodiode 5 and the angle of the obliquely traveling light beam 8r, the light beam 8r can be prevented from entering the light receiving range of the photodiode 5 at all. Such an effect is caused by the angle of the end face 11b of the optical fiber 11, and furthermore, the light ray 8r
Can be realized by selecting the degree of convergence (effective NA: effective numerical aperture).

As described above, the laser light source 2 of the coupling lens 3
Is selected, the first optical signal S1 generated from the laser light source 2 does not return to the laser light source 2 side, and the laser transmission characteristics do not become unstable. . Since the antireflection film 5a is formed on the surface of the photodiode 5, the light amount of the second optical signal S2 can be efficiently converted from light to electricity. If the total reflection film is formed on the side surface 4 b of the rising mirror 4, that is, the side surface 4 b on the photodiode 5 side, the second optical signal S <b> 2 from the optical fiber 11 is temporarily irradiated on the side surface 4 b side of the rising mirror 4. However, the second optical signal S2 can be reflected by the total reflection film on the side surface 4b and made incident on the photodiode 5 side.
2 can be prevented from decreasing. The angle θ1 of the rising mirror 4, that is, the angle θ with respect to the semiconductor substrate 6
1 is inclined at approximately 45 °, and the total reflection film 4a is formed on the inclined surface, so that there is no phenomenon that the first optical signal S1 passes through the rising mirror 4 and reaches the photodiode 5. Does not occur.

The most significant feature is that the optical fiber 11
When the second optical signal S2 is received by the photodiode 5 from the light source, the light 8r of the first optical signal S1 as shown in FIG.
Reach the outside of the light receiving area of the photodiode 5, so that the photodiode 5 does not cause a crosstalk (stray light) phenomenon with respect to the second optical signal S2. Therefore, transmission / reception efficiency in the transmission / reception device can be improved. Even if a total reflection film 4a is not formed on the rising mirror 4 but a reflection film other than the total reflection film is formed, the first optical signal S1 in the photodiode 5 may be used.
And the second optical signal S2 can be substantially prevented from crosstalk.

As described above, the optical path of the first optical signal S1 and the optical path of the second optical signal S2 can be completely separated. Further, the first optical signal S1 is incident on the end face 11b of the optical fiber 11 at an angle θ only by forming a total reflection film or another reflection film on the rising mirror 4 made of, for example, glass or plastic. Therefore, it is not necessary to use a large beam splitter as in the related art, and the manufacturing cost can be reduced.

Next, an example of the characteristics of the optical fiber will be described with reference to FIGS. FIG.
The outer diameter of the optical fiber is, for example, 1000 μm, the outer diameter of the coating is 2.2 mm, and the coating material is polyethylene. The optical fiber includes, for example, a core and a clad that covers the core, and the outer periphery of the clad is covered with a jacket made of a coating material such as the above-described polyethylene. When the wavelength of the light from the laser emission source is monochromatic parallel light of 650 nm,
The transmission loss of the optical fiber 11 is, for example, 14 dB / 100.
m and the band is 160 MHz.

FIG. 7 shows an example of a loss spectrum of the optical fiber. In this figure, the excitation NA = 0.1 means that the first optical signal S1 and the second optical signal S2 have a numerical aperture NA = 0. 1 means that the light was incident on the end face of the optical fiber. In this case, the transmission loss can be kept relatively small, for example, at a wavelength of 650 nm.

Next, another embodiment of the optical transceiver of the present invention will be described with reference to FIG. Note that, regarding another embodiment of the optical transmitting and receiving apparatus of the present invention described below, portions different from the embodiment of FIGS. 3 to 5 will be described, and the same components as those of the embodiment shown in FIGS. The same reference numerals are given to the portions, and the description is omitted. 8, the laser light source 2, the optical device 20, the photodiode 5, and the like are substantially the same, but the structure of the connector 10a of the optical fiber 11 is different. In the embodiment of FIG. 3, the connector 10 is provided with a hole 10f for passing the optical fiber 11, and the optical fiber 11 is inserted into the hole 10f so that the end face 11b of the optical fiber 11 is connected to the photodiode 5. You can be face to face.

On the other hand, the connector 10a shown in FIG.
Are formed to protrude, for example, in a cylindrical shape from the upper end of the package 7. For example, a circular hole 10c is formed at the upper end of the connector portion 10a.
The end 11a of the optical fiber 11 can be inserted into 0c. A light absorber (or absorption film) 10 as a light shielding means is provided on the inner side of the connector portion 10a.
b is provided. The light absorber 10b is provided at a corresponding position where the light beam 8 reflected by the total reflection film 4a of the rising mirror 4 reaches. That is, when the optical fiber 11 is pulled out from the connector portion 10a in the direction of the arrow Y, the light beam 8 is absorbed by the light absorber 8b, thereby preventing the light beam 8 from leaking out of the package 7. I have. This prevents the light beam 8 from exiting the optical transceiver and entering the human eyes or skin. In the unlikely event that the optical fiber 11 is disconnected from the connector 10a by some external force while the laser light source 2 is operating,
It is possible to reliably prevent the light beam 8 as a laser beam from leaking to the outside.

If the light shielding means is the light absorber 10b,
Since the light beam 8 is absorbed, the light beam 8 does not enter the photodiode 5 as stray light, so that occurrence of crosstalk in the photodiode 5 can be prevented. This can be realized by the light beam 8 traveling obliquely with respect to the end face 11b of the optical fiber 11 and by preventing the light beam 8 from spreading significantly. FIG. 9 shows an example in which another member 10d is provided in the embodiment of FIG. 3 and a light absorber 10b is provided.

Next, FIG. 10 shows still another embodiment of the optical transmitting / receiving apparatus of the present invention. In the embodiment of FIG. 10, when compared with the embodiment of FIG. 3, the coupling lens 3 is replaced with the coupling lens 103, and the rising mirror 4 of FIG. I have. The first optical signal S1 as the laser light L of the laser light source 2 is collected by the coupling lens 103,
The optical path is bent by the total reflection film 104a of the rising mirror 104 so that the light ray (incident light) 8 is incident on the end face 11b of the optical fiber 11 at an angle θ along the R1 direction. That is, in FIG. 3, the center of the coupling lens is shifted by the distance d from the center of intensity of the first optical signal S1, but in FIG. 10, the center of intensity of the first optical signal S1 is different from that of the coupling lens which is a convex lens. The center of 103 is not displaced and coincides. Therefore, the coupling lens 1
03 can be suppressed and the optical coupling efficiency can be further improved.

The angle θ2 of the rising mirror 104 is
The angle is set to be smaller than 45 °, and the reflected light beam 8r can be applied to the semiconductor substrate 6 at an angle. By arbitrarily selecting the angle θ2 of the rising mirror 104, the position of the end face 11b of the optical fiber 11 can be freely selected. Of course, the coupling lens 3 of FIG.
May be used in combination.

FIG. 11 shows still another embodiment of the optical transceiver of the present invention. In FIG. 11, a transparent cover component 1 is provided between the optical fiber 11 and the group of the laser light source 2, the optical device 20 and the photodiode 5.
2 are arranged. This cover part 12 has a hole 10f.
From entering the laser light source 2, the optical device 20, the photodiode 5, and the like. This cover part 12
Can be made, for example, like glass or plastic, but even if this cover part 12 is present, in particular, between the optical device 3 or the photodiode 5 and the optical fiber 11, the light beam 8 End face 11b of fiber 11
Can be utilized at an angle .theta. That is, the cover component 12 is provided with an antireflection film that matches the wavelength of the laser light source 2. However, it is technically difficult for the cover component 12 to transmit the light beam 8 to the end face 11b without reflecting the light beam 100%, and a light beam having a certain intensity of the light beam 8 is reflected by the cover component 12 in the direction of arrow R2. Is done. However, the light rays 8r, 8r reflected on the front and back of the cover component 12 can reach the outside of the area of the photodiode 5 so as to avoid the light receiving surface of the photodiode 5, and do not become stray light in the photodiode 5.

FIG. 12 shows still another embodiment of the optical transceiver of the present invention. The embodiment of FIG. 12 differs from the embodiment of FIG. 11 in the following points. The cover component 12 is arranged in the package 7 at an angle θ4. The optical fiber 11 also has its central axis CL
Are disposed at an angle θ4 with respect to the package 7. By arranging the cover component 12 and the optical fiber 11 at an angle with respect to the package 7 in this manner, the light beam 8r reflected by the cover component 12 and the light beam 8r reflected by the end face 11b are also reflected by the photodiode 5. It is possible to reach a region other than the light receiving surface. Thus, crosstalk in the photodiode 5 can be prevented. As shown in the area (A) of FIG. 12, if the end face 11d of the optical fiber 11 is formed beforehand without tilting the center axis CL of the optical fiber 11, the cross-section of the photodiode 5 by the light beam 8r can be similarly obtained. Talk can be prevented.

Next, in the embodiment of the optical transmitting / receiving apparatus of the present invention shown in FIG. 13, a condenser lens (condenser) 13 is arranged between the end face 11b of the optical fiber 11 and the photodiode 5. Thus, the second optical signal S2 emitted from the optical fiber 11 is received by the photodiode 5 after being collected by the lens 13, so that the optical coupling efficiency between the second optical signal S2 and the photodiode 5 is reduced. Can be improved.

In the embodiment of the optical transmitting / receiving apparatus of the present invention shown in FIG. 14, the rising mirror 4 and the coupling lens 3 in the optical device 20 are integrated. Optical device 20 is the first
The function of bending the optical path of the optical signal S1 into the light beam 8 is the same as that of the optical device 20 in FIG. By integrating the coupling lens 3 and the rising mirror 4 in this manner, the number of components can be reduced, and the optical device 20 can be attached to the semiconductor substrate 6 by a single bonding operation. Optical positioning of the lens and the rising mirror is not required.

In the embodiment of the optical transmission / reception device of the present invention shown in FIG. 15, the coupling lens 3 is disposed on the transparent cover part 12. That is, the optical device 20 includes the coupling lens 3 and the rising mirror 4, but the coupling lens 3
It is disposed integrally with the cover component 12 between the rising mirror 4 and the end face 11 b of the optical fiber 11.
The first optical signal S1 of the laser light source 2 is
After being reflected by the total reflection film 4a, the light is condensed by the condensing lens 3, and as a result, the light is obliquely incident on the end face 11b of the optical fiber 11 at a predetermined angle.

In the embodiment of the optical transmission / reception device of the present invention shown in FIG. 16, the optical device 20 includes not only the first optical signal S1 but also the first optical signal S1.
It also has a function of guiding the second optical signal S2. The intensity of the first optical signal S1 is centered by the coupling lens 3 having the same function as the coupling lens 3 shown in FIG. 3 and the total reflection film 4a of the rising mirror 4 having the same function as the rising mirror 4 shown in FIG. The portion is bent to become a light ray 8, and this light ray 8 is incident on the end face 11b of the optical fiber 11 at an angle θ along the direction of the arrow R1. On the other hand, the second optical signal S2 that has passed through the optical fiber 11 passes through the prism 4c of the optical device 20, and is received on the light receiving surface of the photodiode 5.

FIG. 17 shows still another embodiment of the present invention. The first optical signal S1 of the laser light source 2 is directly transmitted to the optical fiber 11 through the coupling lens 3 (convex lens) of the optical device 20. The light is obliquely incident on the end face 11b at an angle of θ. That is, the rising mirror 4 and the like described above are not required.

As described above, in the embodiment of the present invention, not only the efficiency of optical coupling from the optical fiber to the photodiode can be increased, but also the reflected light of the first optical signal is transmitted to the photodiode. It is possible to prevent crosstalk caused by incidence along with an optical signal. That is, the coupling efficiency when the second optical signal is received by the photodiode can be improved, and crosstalk (stray light) can be reduced or eliminated. Since there is no need to use a conventionally used large beam splitter, the cost can be reduced.

In the embodiment of the present invention, when performing one-core bidirectional optical communication using an optical fiber, the optical path incident from the light source to the optical fiber and the optical path incident from the optical fiber to the light receiving means are substantially equal to each other. By completely separating,
The following effects are obtained. (1) Crosstalk between the first optical signal S1 for transmission and the second optical signal S2 for reception can be reduced. (2) The optical coupling efficiency between the optical fiber and the light receiving means can be increased.

The present invention is not limited to the above embodiment. In the above-described embodiment, the embodiment of the optical transmission / reception device of the present invention is used for constructing a home control system or multimedia network. However, the present invention is not limited to this, and the optical transmitting and receiving apparatus of the present invention can be applied to a communication system for exchanging various kinds of information in a moving body such as an automobile, an airplane, and a ship. Further, the wavelength of the laser light source as the light emitting means is not limited to 650 nm, and it is of course possible to use another wavelength region. The light emitting means is not limited to the laser light emitting source, and it is of course possible to use other types of light emitting sources. When the optical fiber is attached to the package, it is a matter of course to provide a holding means for positioning the optical fiber with respect to the package so as not to move in the axial direction of the optical fiber.

[0043]

As described above, according to the present invention,
It is possible to prevent the occurrence of crosstalk when performing optical transmission and reception, and to increase the optical transmission and reception efficiency.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example in which an optical transmission / reception apparatus and an optical transmission / reception method of the present invention are used for information communication of a control system or a multimedia system in a home.

FIG. 2 is a diagram simply showing an example in which the optical transmitting / receiving device of the present invention is disposed between devices.

FIG. 3 is a sectional view showing a preferred embodiment of the optical transceiver of the present invention.

FIG. 4 is a diagram showing a state in which light reflected on an end face of an optical fiber reaches a region other than a light receiving region of a photodiode in the embodiment of FIG. 3;

FIG. 5 is a perspective view showing an embodiment of the optical transceiver shown in FIGS. 4 and 5;

FIG. 6 is a diagram illustrating an example of characteristics of an optical fiber.

FIG. 7 is a diagram showing an example of a loss spectrum of an optical fiber.

FIG. 8 is a diagram showing another embodiment of the optical transceiver of the present invention.

FIG. 9 is a diagram showing another embodiment of the optical transceiver of the present invention.

FIG. 10 is a diagram showing another embodiment of the optical transceiver of the present invention.

FIG. 11 is a diagram showing another embodiment of the optical transceiver of the present invention.

FIG. 12 is a diagram showing another embodiment of the optical transceiver of the present invention.

FIG. 13 is a diagram showing another embodiment of the optical transceiver of the present invention.

FIG. 14 is a diagram showing another embodiment of the optical transceiver of the present invention.

FIG. 15 is a diagram showing another embodiment of the optical transceiver of the present invention.

FIG. 16 is a diagram showing another embodiment of the optical transceiver of the present invention.

FIG. 17 is a diagram showing another embodiment of the optical transceiver of the present invention.

FIG. 18 is a diagram showing a conventional optical transmitting / receiving device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical transmission / reception apparatus, 2 ... Laser light emission source (light emitting means), 3 ... Coupling lens of optical apparatus, 4 ... Startup mirror of optical apparatus, 5 ... Photodiode (Light receiving means) ), 7: package, 8: light beam (incident light), 11: optical fiber, 11a: end portion, 11
b: end face of optical fiber, 20: optical device, S1
... First optical signal, S2 ... Second optical signal

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kenichi Okubo 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Kuniyoshi Shino 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo No. Sony Corporation

Claims (8)

[Claims] 1. A first optical signal to be transmitted, which is connected to an optical fiber used in a single-core bidirectional optical communication circuit, is incident on an end of the optical fiber, and is transmitted through the optical fiber. An optical transmitting and receiving device for receiving an incoming second optical signal; a light emitting unit for emitting the first optical signal; a light receiving unit for receiving the second optical signal emitted from the end of the optical fiber; An optical device for causing the first optical signal of the light emitting means to enter the incident end of the optical fiber along a direction different from the direction in which the second optical signal exits from the end of the optical fiber. When the first optical signal is made incident on an end of the optical fiber, the first light signal is reflected outside the end of the optical fiber, and the light received outside the area where the reflected light arrives. Note that the means are Optical transmitting and receiving device. 2. The optical device, comprising: a light-collecting member for condensing the first optical signal of the light-emitting means; an optical path of the condensed first optical signal; The optical transmitting / receiving device according to claim 1, further comprising: a direction changing element that converts the light into a direction different from the direction of light emitted from the end and causes the light to enter the end of the optical fiber. 3. A direction changing element of the optical device, the reflecting surface for changing an optical path of the first optical signal to a direction different from a direction in which the second optical signal is emitted from an end of the optical fiber. 3. The optical transceiver according to claim 2, further comprising a reflection film. 4. The optical transceiver according to claim 3, wherein the reflection film is a total reflection film. 5. A light receiving device, the optical device, and a package for housing the light receiving device, wherein the end of the optical fiber is detachably attached to the package toward the light receiving device. 2. The optical transmitting and receiving device according to 1. 6. The package according to claim 5, wherein light shielding means for preventing light of the light emitting means from leaking from the package when the optical fiber is detached from the package is arranged in the package. Optical transceiver. 7. The optical transmitting and receiving apparatus according to claim 1, further comprising a light-collecting element for collecting the second optical signal and making the second optical signal incident on the light receiving unit. 8. A first optical signal to be transmitted, which is connected to an optical fiber used in a single-core bidirectional optical communication circuit, is incident on an end of the optical fiber, and is transmitted through the optical fiber. An optical transmission / reception method for receiving an incoming second optical signal, wherein the first optical signal of the light emitting means is directed along a direction different from a direction in which the second optical signal is emitted from the end of the optical fiber. The light receiving means receives the second optical signal emitted from the end of the optical fiber, and the light receiving means receives the second optical signal emitted from the end of the optical fiber, and receives the first optical signal at the end of the optical fiber. An optical transmission / reception method, which does not receive reflected light.