JPH05100132A - WDM transmission / reception module - Google Patents

Abstract

(57) [Abstract] [Purpose] A compact and low-cost module that facilitates adjustment of optical coupling between the light emitting and receiving element and the waveguide, achieves higher efficiency and output, and has electrical and optical low crosstalk. I will provide a. [Structure] Light is emitted from a light emitting device package 6 with an aspherical lens, propagates through an antireflection coated glass 11, a multiplexing waveguide 5, and a directional coupler 3 and is coupled to an optical fiber 2. On the other hand, the light from the optical fiber 2 is demultiplexed by the directional coupling portion 3, propagates through the demultiplexing waveguide 4, enters the light receiving element package 8 with the aspherical lens, and is condensed on the light receiving element. In order to reduce the influence of reflection, non-reflection coated glass is attached to the waveguide substrate 1 on the side where the light emitting device package 6 with an aspherical lens is attached.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitter / receiver module for optical wavelength division multiplexing used in various optical communication equipment fields.

[0002]

2. Description of the Related Art FIG. 8 shows the structure of a conventional wavelength division multiplexing transmission / reception module (Japanese Unexamined Patent Publication No. 60-184216). The optical multiplexer / demultiplexer in which the interference film filter 87 is adhered to the light emitting element package 83, the light receiving element package 84, the common holder 85, and the glass block 86 is mounted on the ceramic substrate 81.

As shown in FIG. 8, a light emitting device package 8 is provided.
The parallel beam of wavelength λ1 from the laser beam 3 is generated by the interference filter 8
7. The light passes through the glass block 86 and is focused on the optical fiber 82 by the common holder 85. On the other hand, the light of wavelength λ2 from the optical fiber 82 is converted into a parallel beam by the common holder 85, reflected by the interference film filter 87, and reflected by the glass block 8.
After passing through 6, the light is collected on the light receiving element by the lens of the light receiving element package 84. The interference film filter 8 is mounted on the light emitting / receiving element packages 83, 84, the common holder 85, and the glass block 86.
The optical multiplexer / demultiplexer to which 7 is bonded is integrated on the ceramic substrate 81.

In the wavelength division multiplexing transmission / reception module of FIG. 8 having such a configuration, since the optical multiplexing / demultiplexing is performed by the interference film filter 87, the multiplexing / demultiplexing characteristic has a large degree of freedom in the design of the filter, so that it is relatively easy to obtain a wide band. Thus, it is possible to obtain a multi-demultiplexing characteristic with low crosstalk. Further, on the ceramic substrate 81, the light emitting device package 83, the light receiving device package 84,
Since the glass block 86 and the common holder 85 are mounted, there is an advantage that multi-mode optical fibers can be collectively assembled without adjustment.

[0005]

In the above-mentioned prior art, since the multiplexing / demultiplexing glass block has an optical path as shown in FIG. 8, there is a certain size limitation and it is difficult to reduce the size.
Further, it is difficult to reduce the price because the glass block is required to be processed with high accuracy. Further, when a single mode fiber is used for the transmission line, it is impossible to assemble the module without adjustment because the optical axis must be adjusted with high accuracy during assembly. That is, assuming that the optical axis direction is the Z axis, the two axes X and Y perpendicular to the Z axis are perpendicular.
Since it is necessary to simultaneously adjust the axis, the tilt θ of the XZ plane, the tilt φ of the YZ plane, and the five axes of the distance Z between the common holder lens and the optical fiber, the assembly process is complicated and the number of man-hours is large. It is difficult to produce and reduce the price.
Furthermore, to prevent condensation, when fixing the case in an airtight manner,
There is a problem that a large force is applied to the ceramic substrate to cause an optical axis shift, resulting in an increase in loss. In addition, since the coupling optical system uses a spherical lens, it is difficult to realize high efficiency and high output due to the influence of spherical aberration.

An object of the present invention is to provide a module which has low electro-optical crosstalk, high efficiency, high output, small size and low cost.

Another object of the present invention is to provide a module in which the influence of light reflection of the light emitting element itself is reduced.

[0008]

In order to achieve the above object, the present invention adopts a waveguide type substrate having a directional coupler as a constituent element, which can be easily mass-produced and can be made small in size and low in cost.
Further, as a light emitting and receiving element package, a light emitting and receiving element package with an aspherical lens, which can be coupled with a waveguide only by adjusting two axes (X axis and Y axis) and has a large numerical aperture and no spherical aberration, is used. It is mounted on a module package, and the light emitting and receiving element packages are arranged in a right-angled positional relationship with each other in order to reduce electrical and optical crosstalk, thereby eliminating the adjustment of the Z axis and the X axis and Y axis. The adjustment tolerance of the shaft can be relaxed more than before, and the structure is such that higher efficiency and higher output than before can be obtained. According to the present invention, the waveguide substrate and the light emitting and receiving device package with the aspherical lens facing the end face thereof are respectively arranged at positions where electrical and optical crosstalk are reduced, and are integrated into the same module package. It was characterized by doing.

In order to achieve another object, the influence of the reflection of light from the light emitting device itself is reduced by attaching a non-reflective coating glass to the waveguide substrate on the side where the light emitting device package is mounted. To do.

[0010]

In the present invention, the waveguide substrate having the directional coupler as a component has a multiplexing / demultiplexing function. Further, by disposing the light emitting and receiving element package with the aspherical lens facing the waveguide end face of this substrate, when the optical axis direction is the Z axis, the two axes X and Y perpendicular to the Z axis have no Z axis. For the adjustment, X-axis, and Y-axis, it is possible to reduce the tolerance during adjustment, and realize high efficiency and high output. The light emitting device package and the light receiving device package are arranged at right angles to the respective packages so as to reduce electrical and optical crosstalk, and the optical fiber and the waveguide are fused or aspherical. It functions as a wavelength multiplex transmission / reception module by being coupled via a lens and further integrated into a module package.

Further, by attaching non-reflective coating glass to the waveguide substrate on the side where the light emitting device package is mounted, the light emitted from the light emitting device is reflected on the waveguide substrate,
It is possible to reduce the incidence of light on itself and to stably supply light as a light source.

[0012]

Embodiments of the present invention will be described below with reference to FIGS.
This will be described with reference to FIGS. 4, 5, 6 and 7.

FIG. 1 is a plan view of a simplified main part of a wavelength division multiplexing transmission / reception module according to an embodiment of the present invention. In the figure, the light of wavelength λ1 from the light emitting element is emitted from the light emitting element package 6 with the aspherical lens holder 7, and the antireflection coated glass 11, the multiplexing waveguide 5, and the directional coupler 3 are provided.
Is propagated and is coupled to the optical fiber 2 attached to the end face of the directional coupler 3 by fusion bonding A. On the other hand, the optical fiber 2
The light of wavelength λ2 from is propagated through the directional coupling portion 3 and the demultiplexing waveguide 4, enters the light receiving element package 8 with the aspherical lens holder, and is condensed on the light receiving element.

FIG. 2 is a sectional view of a main part of a light emitting and receiving element package with an aspherical lens holder. In the figure, a lens holder 23 in which an aspherical lens 22 is housed in the peripheral portion of a glass window cap of the light emitting and receiving element package 21.
After the optical axis adjustment, is fixed by resistance welding or YAG laser welding.

FIG. 3 shows the relationship between the distance between the light emitting element chip and the waveguide (inter-object distance) and the coupling loss in coupling the light emitting element package with the aspherical lens holder to the waveguide. From the figure, when the object-image distance is optimized, the coupling loss is 3
It can be seen that the coupling is about dB and the coupling is highly efficient. For example,
When the light output of the light emitting element chip is 5 mW, it is possible to obtain about 2 mW at the fiber end light output.

FIG. 4 shows an allowable error range between the light emitting device package with the aspherical lens holder and the waveguide when the X and Y axes are deteriorated by 1 dB. From this figure, it can be estimated that the adjustment of the X and Y axes can be relaxed.

FIG. 5 shows an allowable error range between the light emitting device package with the aspherical lens holder and the waveguide when the Z axis is deteriorated by 1 dB. From this figure, when the object-image distance is 11 mm, which is the optimum with respect to the Z axis, there is about 100 μm, and no adjustment is possible. Further, the light receiving element package can be similarly coupled with the waveguide.

FIG. 6 shows another embodiment of the present invention. This embodiment also operates similarly to the above-mentioned embodiments. However, the difference from the above-described embodiment is that the directional coupler 3
The point is that the optical fiber 2 and the optical fiber 2 are not fused but joined by a fiber collimator 12 with an aspherical lens.

FIG. 7 shows a sectional view of the main part of the fiber collimator package. After adjusting the optical axis of the lens holder 74 in which the aspherical lens 75 is stored in the peripheral portion of the holder 73 holding the ferrule 72 attached to the tip of the optical fiber 71, resistance welding or YAG laser welding is performed. Fix it.

In order to achieve another object, the present invention is non-reflective at the end face of the multiplexing waveguide 5 so that the light emitted from the light emitting device package 6 is reflected at the end face of the multiplexing waveguide 5 and does not return to the light emitting device. Bond the coated glass with a photo bond. As a result, the reflected return light is affected by the light incident on the light emitting element package 6 itself, and the light emitting element is prevented from being unable to stably supply light.

In the present invention, the waveguide type substrate 1 and the light emitting and receiving element packages 6 and 8 are integrated with the module package 10 and sealed.

An example of the assembling method will be described below with reference to FIG.
First, metallize the module package 10 on one side,
Further, the waveguide substrate 1 with the optical fiber 7 fused is set to Au /
Metal is fixed to the inside of the module package 10 with Su eutectic high-temperature solder or the like, the light emitting and receiving element packages 6 and 8 with aspherical lenses are inserted from the side surface of the module package 10, and laser welding is performed after position adjustment of the X and Y axes. , Pb /
Fix metal with Su eutectic solder. At this time, in the Z-axis direction, as described above, non-adjustable assembly can be performed with mechanical part processing accuracy. At this time, since the light emitting and receiving element is already hermetically sealed with the light emitting and receiving element packages 6 and 8 with the aspherical lens, the reliability of the element is affected even when the laser welding and the soldering are not hermetically sealed. do not do. Further, even when the module is sealed to prevent dew condensation, high-performance hermetic sealing is not required, so that the module can be sealed relatively easily.

[0023]

According to the present invention, by using a waveguide substrate having a directional coupler as a constituent element in the multiplexer / demultiplexer, a light emitting / receiving element with an aspherical lens that can be easily coupled to the waveguide is used. Using an element package, these are made into a module package,
By adjusting the two axes less than the conventional five axes and making it hermetically sealed, mass production becomes possible, high efficiency,
High output, small size, and low price.

Further, by disposing the light emitting device package and the light receiving device package at positions separated from each other at a right angle to each package, electrical and optical low crosstalk is achieved.

Further, by attaching a non-reflective coating glass to the waveguide substrate on the side where the light emitting device package is mounted, the light emitted from the light emitting device package is reflected by the waveguide substrate and enters the light emitting device package to emit light. The characteristics of the device are less affected.

[Brief description of drawings]

FIG. 1 is a plan view of a main part of an embodiment of the present invention,

FIG. 2 is a sectional view of a main part of a light emitting and receiving element package with an aspherical lens holder,

FIG. 3 is a coupling loss characteristic diagram of a light emitting and receiving element package with an aspherical lens holder,

FIG. 4 is a permissible error range characteristic diagram regarding X and Y axes of a light emitting and receiving element package with an aspherical lens holder,

FIG. 5 is a characteristic diagram of a permissible error range about the Z axis of a light emitting and receiving element package with an aspherical lens holder,

FIG. 6 is a plan view of an essential part of another embodiment of the present invention,

FIG. 7 is a sectional view of a main part of a fiber collimator package,

FIG. 8 is a plan view of a main part of a wavelength division multiplex transmission / reception module using a conventional glass block type multiplexer / demultiplexer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Waveguide type substrate, 2 ... Optical fiber, 3 ... Directional coupler, 4 ... Demultiplexing waveguide, 5 ... Multiplexing waveguide, 6 ... Light emitting element package, 7 ... Aspherical lens holder, 8 ... Light receiving element package, 9 ... Aspherical lens holder, 10 ... Module package, 11 ... Antireflection coated glass.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location H04J 14/02 (72) Inventor Masahiro Usami 216 Totsuka-cho, Totsuka-ku, Yokohama Hitachi, Ltd. Totsuka Plant (72) Inventor Tatsuto Shimura 216 Totsuka-cho, Totsuka-ku, Yokohama-shi Hitachi Ltd. Totsuka factory

Claims (4)

[Claims] 1. A wavelength division multiplex transmission / reception module comprising a light emitting element package with an aspherical lens, a light receiving element package with an aspherical lens, and a waveguide substrate mounted in the same package. 2. A waveguide substrate having an optical multiplexing / demultiplexing function, wherein a directional coupling portion composed of straight and curved optical waveguides is formed as a constituent element, and a multiplexing waveguide through which the multiplexed light propagates. , A demultiplexing waveguide through which the demultiplexed light propagates, and a directional coupling portion through which the demultiplexed light and the multiplexed light propagate together, and an aspherical surface is provided at a position opposite to the end face of the multiplexing waveguide. A light emitting device package with a lens is arranged, a light receiving device package with an aspherical lens is arranged at a position facing each other on the end face of the demultiplexing waveguide, and the light emitting device package and the light receiving device package are arranged in a mutually perpendicular positional relationship. A wavelength division multiplexing transmission / reception module in which an optical fiber is fused to the common waveguide. 3. The wavelength division multiplex transmission / reception module according to claim 1, wherein an antireflection coated glass is attached to an end surface of the waveguide substrate on the side where the light emitting device package is attached. 4. The wavelength multiplexing transmission / reception module according to claim 1, wherein the common waveguide and the optical fiber are coupled by using a fiber collimator using an aspherical lens.