JP2000329958A - Optical transmitter receiver module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical transmitter receiver module capable of being micronized, relaxing the mounting accuracy of a photodiode element for monitoring, and reducing the variance of a monitor current. SOLUTION: The optical waveguide substrate 1 is provided with a transmitting laser diode element 6 for emitting transmitting light while accompanying back light, a receiving photodiode element 7 for receiving signal light from the outside, a monitor photodiode element 4 for receiving the back light and monitoring the transmitting light, and an optical waveguide 2 for guiding the transmitting light to the outside as well as guiding the signal light from the outside to the receiving photodiode element 4. In this case, on the optical waveguide substrate 1, a monitor optical waveguide 3 is formed which is for guiding the back light of the transmitting laser diode element 6 to the monitor photodiode element 4. Consequently, the degree of freedom is enhanced on the arrangement of the monitor photodiode element 4 for the optical waveguide substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical transceiver module for optical communication, and more particularly to a mounting structure of a monitoring light receiving element for monitoring the optical output of a light emitting element that emits transmission light.

[0002]

2. Description of the Related Art Generally, an optical transmission / reception module (optical communication waveguide module) using an optical waveguide is transmitted from a laser diode element (transmission LD element) for emitting transmission light and a transmission path. There are three types of photodiode elements (receiving PD elements) for receiving incoming optical signals, and monitoring photodiode elements (monitoring PD elements) for monitoring output light (that is, transmitting light) of LD elements. An optical semiconductor element is mounted.

[0003]

Among the three types of optical semiconductor elements, the monitoring PD element is described below.
The backside light emitted by the transmitting LD element is directly received, and it is necessary to mount it near the transmitting LD element. Therefore, the degree of freedom of the mounting position of the monitor PD element in the optical transmitting / receiving module is small, and it is difficult to reduce the size of the optical transmitting / receiving module.

[0004] Further, a transmission LD is provided by a monitor PD element.
The structure is such that the backside light of the element is directly received, and the dispersion of the monitor current due to the mounting accuracy of the transmission LD element and the monitor PD, or the dispersion of the backside radiation angle of the transmission LD element is large, and the module yield is reduced. Had been lowered.

[0005] Furthermore, the optical transmitting / receiving module uses two types of PD elements, one for receiving and the other for monitoring, and requires high-precision positioning for mounting these elements, so that a large number of assembly steps are required. , Making it difficult to lower prices.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and can reduce the size of a module, reduce the mounting accuracy of a monitoring PD element, and reduce variations in monitor current. It is an object of the present invention to provide an optical transmitting and receiving module capable of performing the following.

[0007]

In order to solve the above-mentioned problems, the present invention has the following arrangement. That is, the present invention relates to an optical waveguide substrate (for example, the optical waveguide substrate 1 shown in FIG. 1).
A light-emitting element (e.g., a component corresponding to the transmission laser diode element 6 shown in FIG. 1) mounted on the optical waveguide substrate and emitting transmission light with backside light; A light receiving element (for example, a component corresponding to the receiving photodiode element 7 shown in FIG. 1) mounted outside the optical waveguide substrate and receiving the received light; A monitoring light receiving element (for example, a component corresponding to the monitoring photodiode element 4 shown in FIG. 1) for receiving and monitoring the transmission light; and a monitor light-receiving element formed on the optical waveguide substrate and monitoring the back surface light. A monitoring optical waveguide (for example, a component corresponding to the monitoring optical waveguide 3 shown in FIG. 1) for guiding to the light receiving element for light and an optical waveguide formed on the optical waveguide substrate and guiding the transmission light to the outside. An optical waveguide for guiding the signal light from the outside to the light receiving element (component corresponding to the optical waveguide 2 shown in FIG. 1, for example), characterized by comprising a. An emission end of the optical waveguide with respect to the light receiving element (for example, an element corresponding to the emission end of the optical waveguide 2 shown in FIG. 2) and an emission end of the monitoring optical waveguide with respect to the monitoring light receiving element (for example, a monitor shown in FIG. 2) An element corresponding to the output end of the optical waveguide 3)
Are formed together on the same end face side of the optical waveguide substrate, for example.

Further, the present invention provides an optical waveguide substrate (for example, a component corresponding to the optical waveguide substrate 1 shown in FIG. 3), and a light emitting device mounted on the optical waveguide substrate and emitting transmission light with back surface light. An element (e.g., a component corresponding to the transmitting laser diode element 6 shown in FIG. 3) and mounted outside the optical waveguide substrate to receive the receiving light and receive the back light to monitor the transmitting light. A light receiving element (for example, a component corresponding to the receiving photodiode element 7 shown in FIG. 3) and the optical waveguide substrate,
A monitoring optical waveguide (for example, a component corresponding to the monitoring optical waveguide 3 shown in FIG. 3) for guiding the back surface light to the monitoring light receiving element, and the transmission light formed on the optical waveguide substrate and guiding the transmission light to the outside. And an optical waveguide (for example, a component corresponding to the optical waveguide 2 shown in FIG. 3) for guiding signal light from the outside to the light receiving element, and each of the output of the monitoring waveguide and the light waveguide to the light receiving element. The ends are formed to be close to each other.

The main features of the present invention are summarized below. (1) In an optical module using an optical waveguide, a waveguide pattern for guiding the light on the back surface of the transmitting LD element was formed. (2) The back surface light of the transmission LD element is guided through the waveguide pattern and is coupled to the monitoring PD element.

With the above features, the following effects can be obtained. (1) By forming a monitor optical waveguide for guiding the back surface light of the transmission LD element to the monitor PD element, the degree of freedom of the mounting position of the monitor PD element is increased. (2) Since the degree of freedom of the mounting position of the monitoring PD element is increased, it is possible to reduce the variation in the coupling between the rear surface light of the transmitting LD element and the monitoring PD element, and to suppress the variation in the monitor current of the module. (3) When applied to a TCM type optical module, a PD element for light reception and a PD element for monitoring can be realized by one PD element.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In each of the drawings, common elements are denoted by the same reference numerals. <First Embodiment> FIG. 1 shows the configuration of an optical transceiver module according to the first embodiment. In FIG.
Reference numeral 2 denotes an optical waveguide for guiding transmission light and reception light, reference numeral 3 denotes a monitoring optical waveguide for guiding light on the back surface of a later-described transmission laser diode element 6 (transmission LD element), and reference numeral Reference numeral 4 denotes a monitoring photodiode element (monitoring PD element) that receives the back surface light guided to the optical waveguide 3, reference numeral 5 denotes a carrier of the monitoring PD element 4, and reference numeral 6
Is a transmission LD element for emitting transmission light, reference numeral 7 is a reception photodiode element (reception PD element) for receiving reception light, and reference numeral 8 is an optical fiber as an externally connected optical transmission path. V-groove for mounting 9, reference numeral 50
Is the carrier of the PD element 7 for reception, and the LD for transmission 60
The optical filter unit reflects the output light of the element 6 toward the optical waveguide coupled to the optical fiber 9.

Here, on the back side of the transmitting LD element 6 mounted on the optical waveguide substrate 1, a monitoring optical waveguide 3 for guiding the back surface light emitted from the back side of the transmitting LD element 6 is provided.
Is connected to one end, and the other end is a monitoring PD element 4
Is joined to. Thereby, the back surface light emitted from the back surface of the transmission LD element 6 is guided to the monitoring PD element 4 outside the substrate via the monitoring optical waveguide 3.

The monitoring PD element 4 is attached to an arbitrary position outside the optical waveguide substrate 1 so as to be separated from the optical fiber 9 so as not to interfere with the optical fiber 9.
The monitoring optical waveguide 3 is connected to the monitoring PD element 4 by the transmission L
A pattern is formed on the optical waveguide substrate 1 so as to guide light from the back surface of the D element 6.

On the end face of the output end of the monitoring optical waveguide 3,
In order to reduce the return light due to the reflection at this end face and the end face of the monitor PD element 4, an appropriate angle is provided with respect to the traveling direction of the back light, and the back light of the transmission LD element 6 is used for monitoring. The light is emitted from the optical waveguide 3 to the outside of the monitoring optical waveguide 3 at an appropriate angle.

The shape of the core of the monitoring optical waveguide 3 may be formed in a uniform size in the longitudinal direction.
Alternatively, the transmission LD element 6 can be coupled to the monitor optical waveguide 3 with high efficiency.
May be formed in an expanded shape.

The operation of the first embodiment will be described below. The transmission light emitted from the transmission LD element 6 is reflected by the optical filter unit 60, coupled to the optical fiber 9, and propagates to the transmission line. At this time, the back light of the transmission LD element 6 is transmitted to the monitor optical waveguide 3 behind the transmission LD element 6.
The light propagates through the monitoring optical waveguide 3, exits from the waveguide substrate 1, and is received by the monitoring PD element 4.
The signal light propagating through the external transmission path enters the optical waveguide 2 from the optical fiber 9, passes through the optical filter unit 60, and is received by the receiving PD element 7 mounted outside the substrate. As described above, transmission and reception of signal light are performed by one module.

Here, according to the optical transceiver module according to the first embodiment, the following effects can be obtained. That is, since the back surface light of the transmission LD element 6 is guided in the monitoring optical waveguide 3 and received by the monitoring PD element 4, the transmission LD element 6 can be received from an arbitrary position on the optical waveguide substrate 1. Can be emitted. Therefore, the degree of freedom of the mounting position of the monitoring PD element 4 is improved, and the module can be reduced in size and the assembling work can be improved.

According to the prior art, it is necessary to mount the monitoring PD element 4 obliquely in order to reduce the reflected light returning from the surface of the monitoring PD element 4. According to the embodiment, the pattern at the end of the optical waveguide is formed obliquely, and the back surface of the transmission LD element 6 is emitted to the monitor PD element 4 side at an angle to the end face. It is not necessary to mount the monitor PD element 4 obliquely, and the mounting accuracy of the monitoring PD element 4 is reduced.

Further, since the back surface light of the transmission LD element 6 is coupled to the monitoring PD element 4 via the monitoring optical waveguide 3, the monitoring P element 4 is combined with the above-described mounting accuracy reduction.
It is possible to reduce the variation of the monitor current obtained by the D element.

<Second Embodiment> Next, a second embodiment of the present invention will be described. FIG. 2 shows the configuration of the optical transceiver module according to the second embodiment. The monitoring optical waveguide 3 for guiding the back light of the transmission LD element 6 includes a mirror 10
And the output end thereof is formed so as to be located near the output end of the signal light incident from the optical fiber 9. That is, the emission end of the signal light from the optical fiber 9 and the emission end of the back surface light from the monitoring optical waveguide 3 are both formed on the same surface side of the optical waveguide substrate 1. The monitoring PD element 4 is 1 together with the receiving PD element 7.
It is mounted on one carrier 50 and mounted outside the optical waveguide substrate 1 after performing positioning with respect to the monitoring optical waveguide 3. In this example, the monitoring and receiving PD elements are separately provided, but a PD element for monitoring and receiving may be integrated.

The operation of the second embodiment will be described below. As in the first embodiment, the back surface light of the transmission LD element 6 is coupled to the monitoring optical waveguide 3, reflected by the mirror 10, guided to the vicinity of the emission end of the reception light, and emitted. . The back surface light emitted from the monitoring optical waveguide 3 is received by the monitoring PD element 4 mounted on the same carrier 50 as the receiving PD element 7.

According to the optical transmitting / receiving module according to the second embodiment, the output end of the monitoring optical waveguide 3 for guiding the back light of the transmission LD element 6 is connected to the output end of the signal light incident from the optical fiber 9. , The receiving PD element 7 and the monitoring PD element 4 can be mounted on one carrier 50, the number of components of the module can be reduced, and the number of assembly steps can be reduced. Pricing is possible.

<Third Embodiment> Next, a third embodiment of the present invention will be described. In the third embodiment, the present invention
This is applied to an optical transmission / reception module of the CM system (ping-pong transmission). FIG. 3 shows the configuration of the optical transceiver module according to the third embodiment. In the TCM optical transmission / reception module, transmission and reception are temporally divided, so that one PD element can be used for reception and for monitoring. In the third embodiment, attention is paid to this, and as shown in FIG. 3, the received light and the back surface light are received by the same PD element 70. That is, the monitor optical waveguide 3 for guiding the back surface light of the transmission LD element 6 is formed behind the mounting portion of the transmission LD element 6, and the monitor optical waveguide 3 is folded back with respect to the mirror 10, and The emission end is formed so as to be close to the emission end of the signal light from the optical fiber 9.

According to this configuration, the reception light from the optical fiber 9 and the back light of the transmission LD element 6 are both transmitted to the PD element 70.
Is incident on. Here, since the receiving light and the back light do not occur at the same time, the PD element 70 receives one of the optical signals at different times and converts it into an electric signal.

Therefore, according to the third embodiment,
The PD element 70 can function as a monitoring PD element during transmission of the optical transceiver module, and can function as a receiving PD element during reception. That is, in the conventional module, two PDs are required for reception and monitoring, but with the structure of the present invention, one PD element can realize two functions. As a result, the number of parts and the number of assembly steps can be reduced along with the miniaturization of the module.
Module cost reduction is achieved.

The features of each of the above embodiments will be summarized below. (1) receiving the back light of the transmitting LD element on the optical waveguide,
A waveguide for guiding this is formed, and the light on the back surface is coupled to the monitoring PD element via the waveguide. (2) By providing the monitoring optical waveguide for guiding the light from the back side of the transmitting LD element, the degree of freedom in mounting the monitoring PD element in the optical module is increased. (3) By providing a monitor optical waveguide for guiding the rear surface light of the transmission LD element, the rear surface light and the monitor PD are provided.
Variations in coupling with the element can be reduced, and variations in monitor current obtained by the monitoring PD element can be suppressed. (4) When applied to a TCM (ping-pong transmission) optical transmission / reception module, a function of receiving signal light with one PD element and a function of monitoring backside light become possible. (5) By increasing the degree of freedom in mounting the monitoring PD element, the size of the optical module can be reduced and the assemblability can be improved, and the price of the optical transmitting and receiving module can be reduced.

[0027]

As described above, according to the present invention, the monitoring optical waveguide for guiding the back light of the light emitting element (the transmitting LD element) to the monitoring light receiving element is provided on the optical waveguide substrate. For monitoring the light from the back surface of the light emitting element while miniaturizing the module
The mounting accuracy of the element can be relaxed, and this monitor P
Variations in monitor current obtained by the D element can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an optical transceiver module according to a first embodiment of the present invention;

FIG. 2 is a block diagram illustrating a configuration of an optical transceiver module according to a second embodiment of the present invention;

FIG. 3 is a block diagram illustrating a configuration of an optical transceiver module according to a third embodiment of the present invention;

[Explanation of symbols]

1: optical waveguide substrate 2: optical waveguide 3: monitoring optical waveguide 4: monitoring photodiode element (monitoring PD element) 5, 50: carrier 6: transmission laser diode element (transmission LD element) 7, 70: Photodiode element for reception (PD element for reception) 8: V groove 9: Optical fiber (optical transmission line) 10: Mirror 60: Optical filter section

Claims (3)

[Claims] An optical waveguide substrate, a light emitting element mounted on the optical waveguide substrate and emitting transmission light with backside light, and a light receiving device mounted outside the optical waveguide substrate and receiving reception light A monitoring light receiving element mounted on the outside of the optical waveguide substrate for receiving the rear surface light and monitoring the transmission light; and a monitoring light receiving device formed on the optical waveguide substrate and receiving the rear surface light. A monitoring optical waveguide for guiding to an element; and an optical waveguide formed on the optical waveguide substrate, for guiding the transmission light to the outside and guiding signal light from outside to the light receiving element. Transmit / receive module. 2. An emission end of the optical waveguide with respect to the light receiving element and an emission end of the monitoring optical waveguide with respect to the monitoring light receiving element are both formed on the same end face side of the optical waveguide substrate. The optical transceiver module according to claim 1. 3. An optical waveguide substrate, a light emitting element mounted on the optical waveguide substrate and emitting transmission light with back surface light, and a light emitting device mounted outside the optical waveguide substrate to receive received light and to receive the received light. A light receiving element for receiving light and monitoring the transmission light; a monitoring optical waveguide formed on the optical waveguide substrate and guiding the back surface light to the monitoring light receiving element; formed on the optical waveguide substrate And an optical waveguide for guiding the transmission light to the outside and guiding the signal light from the outside to the light receiving element, wherein the monitor waveguide and the emission end of the optical waveguide for the light receiving element are close to each other. An optical transceiver module formed as described above.