JP2004219646A - Optical transmission and reception module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease the number of components of an optical transmission and reception module and to decrease the places of optical axis alignment. <P>SOLUTION: The optical transmission and reception module has a semiconductor laser, a photodetector, and a fiber-made fusion type optical coupler all arranged on a frame. The semiconductor laser converts a high-frequency electric signal into signal light and outputs it. The photodetector receives signal light and converts it to a high frequency electric signal. The fiber-made fusion type optical coupler has a pair of branched ports. One of the branched ports is a light receiving port disposed in the vicinity of the semiconductor laser, and the other branched port is disposed in the vicinity of the photodiode. The optical coupler also has a common port led out to the outside. The semiconductor laser, photodiode, and fusion type optical coupler are molded into a single body with a light-transmissive resin and fixed on the frame. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical transceiver module used for performing bidirectional communication or the like by wavelength division multiplexing in optical communication.
[0002]
[Prior art]
In a conventional bidirectional optical transmission / reception module, a semiconductor laser, a light receiving element, an optical branching element in which a thin film is deposited on a surface of a flat glass plate, and the like are configured by a micro optical system using a lens (for example, see Patent Document 1). 1).
[0003]
[Patent Document 1]
JP-A-6-138347 (page 2-3, FIG. 1)
[0004]
[Problems to be solved by the invention]
Since the conventional bidirectional optical transmission / reception module is configured as described above, it is necessary to align the optical axes of many individual elements with high accuracy, which requires time for manufacturing steps and a large number of parts. Therefore, there has been a problem that the cost is increased as a whole.
[0005]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to obtain an optical transmitting and receiving module capable of reducing the number of components and the number of optical axis alignment points.
[0006]
[Means for Solving the Problems]
An optical transceiver module according to the present invention includes a semiconductor laser that converts a high-frequency electric signal into a signal light and outputs the same, a light-receiving element that converts a received signal light into a high-frequency electric signal, and one light-receiving port of at least one pair of branch ports. Is placed near the semiconductor laser, the light exit of the other branch port is placed near the photodiode, and a fused optical coupler made of fiber for leading a common port to the outside is arranged on the frame. A laser, a photodiode, and a fused optical coupler are integrated and fixed on a frame by a mold of a translucent resin.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described.
Embodiment 1 FIG.
FIG. 1 is a perspective view showing the structure of the optical transceiver module according to Embodiment 1 of the present invention. In the figure, reference numeral 4 denotes a fused optical coupler. The fused optical coupler used here is also called a melt-stretched WDM (wavelength division multiplexing) optical coupler or a fiber-type WDM optical coupler, and is manufactured by melting and drawing an optical fiber as a material. It is. Since the fusion type optical coupler has a small insertion loss for multiplexing light of different wavelengths, application to a WDM (wavelength division multiplexing) system for multiplexing light of many wavelengths is considered. In the first embodiment, the fusion type optical coupler 4 includes a pair of branch ports 4a and 4b and a common port 4c for transmitting a multiplex of the optical wavelengths λ1 and λ2 of these branch ports.
[0008]
On a frame 1, a semiconductor laser 2, a photodiode (light receiving element) 3, and a fused optical coupler 4 are arranged. The fusion type optical coupler 4 is arranged near the semiconductor laser 2 with the end face of the branch port 4a facing the semiconductor laser 2 as a light receiving port. On the other hand, the branch port 4 b of the fusion type optical coupler 4 is arranged near the photodiode 3 so as to face the photodiode 3. The common port 4c of the fused optical coupler 4 is led out of the frame 1. Further, terminals 6a, 6b, 6c and 6d are formed on the frame 1, and are electrically connected to the semiconductor laser 2 or the photodiode 3, respectively. The arrangement of the semiconductor laser 2, the photodiode 3, and the fused optical coupler 4 is fixed and integrated on the frame 1 by using a mold of a translucent resin 5. As the translucent resin 5, for example, an epoxy resin is used.
[0009]
Next, the operation will be described.
When a high-frequency electric signal is supplied to the terminals 6c and 6d for transmission, the semiconductor laser 2 oscillates in the wavelength band λ1 (for example, 1.3 μm band). Since the light receiving port of the branch port 4a on the wavelength λ1 side of the fused optical coupler 4 is arranged near the semiconductor laser 2, a part of the light emitted from the semiconductor laser 2 (for example, about 10% to 20%) is branched. Coupled to port 4a. The light incident on the branch port 4a propagates through the fiber, and in the coupler section of the fusion type optical coupler 4, most (for example, 90% or more) of the light propagates to the common port 4c and is output to the outside. Since the fused optical coupler 4 generally has a high directivity of 60 dB or more, leakage of the signal light incident on the branch port 4a to the branch port 4b is negligibly small.
[0010]
Next, when performing reception, if signal light of wavelength λ2 (for example, 1.55 μm band) is input to the common port 4c of the fusion type optical coupler 4, the fusion type optical coupler 4 will be mostly (for example, 90% or more) to the branch port 4b of the wavelength λ2. On the other hand, since the fused optical coupler 4 has an isolation of 20 dB to 40 dB, the signal light of the wavelength λ2 is hardly propagated to the branch port 4a of the wavelength λ1. In this case, the isolation depends on the wavelength of the signal light. For this purpose, the branching characteristics of the fused optical coupler 4 can be obtained by adjusting the amount of stretching when forming the branch ports 4a and 4b from the same material. Can be Next, the signal light having the wavelength λ2 that has propagated to the branch port 4b is emitted from the light exit at the end of the fiber. Since the light exit of the branch port 4b is arranged near the photodiode 3, the photodiode 3 receives the optical signal of the wavelength λ2. The optical signal is converted into an electric signal by the photodiode 3 and extracted from the terminals 6a and 6b.
As described above, the transmission and reception of the signal light between the semiconductor laser 2 and the branch port 4a and between the photodiode 3 and the branch port 4b can be performed optically through the translucent resin 5 without using the lens. .
[0011]
As described above, according to the first embodiment, the light-receiving port of at least one of the pair of branch ports 4a is opposed to the vicinity of the semiconductor laser 2 using the fiber-type fused optical coupler 4, and the other branch port is used. The light emitting port of the port 4b faces the photodiode 3 and is disposed so as to lead out the common port 4c to the outside. The semiconductor laser 2, the photodiode 3 and the fused optical coupler 4 are framed by molding a transparent resin. Since it is integrated and fixed on the upper surface, the number of parts for coupling the signal light is small, the number of optical axis alignments can be reduced, and the number of manufacturing steps can be reduced. Is obtained.
[0012]
Embodiment 2 FIG.
Embodiment 2 will be described with reference to FIG.
Between the semiconductor laser 2 and the light receiving port of the branch port 4a, a cap or cover for preventing the intrusion of the mold resin without disturbing the optical coupling is arranged. Further, a cap or a cover is similarly arranged between the photodiode 3 and the light exit of the branch port 4b. From there, the semiconductor laser 2, the photodiode 3, and the fused optical coupler 4 are fixed by resin molding. In addition, the cap or the cover may have a structure that facilitates positioning between the semiconductor laser 2, the photodiode 3, and the fused optical coupler 4. By doing so, the optical signal can be coupled through the space, and an opaque resin can be used as the resin used for the mold.
When a translucent resin is used as in the first embodiment, a cap or a cover may be provided for either one of the optical coupling portions.
[0013]
【The invention's effect】
As described above, according to the present invention, a semiconductor laser that converts a high-frequency electric signal into a signal light and outputs it, a light-receiving element that converts a received signal light into a high-frequency electric signal, and at least one of a pair of branch ports The light-receiving port faces the vicinity of the semiconductor laser, the light-emitting port of the other branch port faces the vicinity of the photodiode, and a fused optical coupler made of fiber for leading a common port to the outside is arranged on the frame. , The semiconductor laser, the photodiode and the fused optical coupler are integrated and fixed on the frame with a transparent resin mold, so the number of parts is small and the number of places where optical axis alignment is required is reduced. As a result, the number of manufacturing steps can be reduced, and as a result, the manufacturing cost of the optical transceiver module can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a structure of an optical transceiver module according to Embodiment 1 of the present invention.
[Explanation of symbols]
1 frame, 2 semiconductor laser, 3 photodiode (light receiving element), 4 fusion type optical coupler, 4a, 4b branch port, 4c common port, 5 translucent resin.

Claims (3)

A semiconductor laser that converts a high-frequency electrical signal into a signal light and outputs the signal light;
A light-receiving element that converts the received signal light into a high-frequency electric signal,
At least one light-receiving port of the pair of branch ports faces the vicinity of the semiconductor laser, and the light-emitting port of the other branch port faces the vicinity of the photodiode. Place the optical coupler and on the frame,
An optical transmitting and receiving module in which the semiconductor laser, the photodiode, and the fused optical coupler are integrated and fixed on the frame with a light-transmitting resin mold. A semiconductor laser that converts a high-frequency electrical signal into a signal light and outputs the signal light;
A light-receiving element that converts the received signal light into a high-frequency electric signal,
At least one light-receiving port of the pair of branch ports faces the vicinity of the semiconductor laser, and the light-emitting port of the other branch port faces the vicinity of the photodiode. An optical coupler,
A cover or cap provided between the light receiving port of the one branch port and the semiconductor laser and between the light emitting port of the other branch port and the photodiode, and through which signal light passes but which prevents resin from entering the mold. On top of
An optical transceiver module in which the semiconductor laser, the photodiode, the fused optical coupler, and the cover or cap are integrated and fixed on a frame using a resin mold. A cover or cap is provided between the light-receiving port of one branch port and the semiconductor laser and between the light-emitting port of the other branch port and the photodiode, and the resin to be molded is made of a translucent resin. The optical transceiver module according to claim 2, wherein

Images