JPH1126875A - Optical composite module - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To mount and fix all light emitting and receiving elements and optical elements on a single substrate, and to mount the optical elements using a passive alignment method. SOLUTION: A plurality of optical elements and a light receiving / emitting element are arranged on a mounting board made of silicon or ceramic on a Peltier element, and the mounting board is divided or integrated into a light source mounting board and an optical element mounting board. This makes it possible to provide an optical composite module having stable characteristics and high reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an optical composite module used for an optical fiber amplifier.

[0002]

2. Description of the Related Art Conventionally, in an optical fiber amplifier, a coupler, a WDM, an in-line optical isolator, various light emitting / receiving components, a rare earth doped fiber, and the like are individually fusion-spliced and configured. Recently, there has been developed an optical composite module in which the function of branching and monitoring input / output light, the function of an in-line optical isolator, and the function of multiplexing pump light are integrated in one module. By using such a module, the optical circuit portion can be constituted by one module, so that the trouble of measurement and evaluation at the time of fusion is eliminated, and the circuit portion is downsized. However, these types of optical composite modules usually attach each optical element to a fixing bracket to fix each optical functional element, for example, beam splitter, WDM filter, in-line optical isolator, and weld and fix it to the case by YAG welding. doing. At that time, the dielectric multilayer film used for the surface treatment of each optical element has a light incident angle dependency in light transmission characteristics and reflection characteristics. Therefore, it is necessary to fix each optical element with a high degree of angular accuracy. From the above, when the conventional method is used, the optical composite module has the following disadvantages.

(1) Fixing of each optical element requires welding fixation by individually and precisely adjusting element fixing brackets, which is troublesome.

(2) Since the optical path system passes through each fixed optical element, its characteristics are liable to change due to slight deflection between the fixed elements.

(3) An excitation light source is not built-in, and it is necessary to separately attach and attach an excitation module by fusion splicing, resulting in poor utilization efficiency and time-consuming production.

(4) The number of manufacturing steps is large, and it is difficult to reduce the cost.

And so on.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve these problems, and an optical composite module in which a Peltier element is provided in a storage case and a mounting board is fixed on the Peltier element. A plurality of optical elements and a light receiving / emitting element are arranged on a mounting board made of silicon or ceramic, and the mounting board is further provided with a light source mounting board on which the light emitting elements are arranged and an optical element mounting board on which the optical elements are arranged The present invention provides an optical composite module divided into:

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a layout view of a first embodiment of the present invention in which a substrate with one electrode is mounted on a Peltier element, and an excitation light source, a WDM element, a branch element, an isolator element, and a light receiving element are mounted and fixed on the substrate. FIG. 2 shows a second embodiment of the present invention, in which the substrate is divided into an excitation light source, a WDM element section and an isolator element, a branch element, and a light receiving element section, and heat radiation from the excitation light source is separated from the substrate. FIG. 3 is a perspective view of the arrangement diagram shown in FIG. 1, and FIG. 4 is a diagram for explaining the function of the optical composite module of the present invention. FIG. 5 is a diagram illustrating an optical composite module including an excitation unit, FIG. 5 is a diagram illustrating an inline optical isolator element according to the present invention, and FIG. 6 is a diagram illustrating a case where a fiber and a lens are mounted on a substrate. FIG. 7 is a block diagram. Is a diagram showing the connection structure between the pumping semiconductor laser and the coupling lens according to the invention.

In FIG. 1, 1 is a substrate, 7 is a Peltier element, 6 is a butterfly type package, 9 is a wedge lens, 21 is a light receiving element, 22 is a light emitting element, 24 is an input port, 25 is an output port, 26 Is a total reflection mirror, and 27 is a beam splitter. These optical elements (2
1, 22) are fixedly mounted on one substrate 1.
The Peltier element 7 for cooling the excitation light source is placed in the case, and the substrate 1 is mounted thereon. The material of the substrate 1 is S
i, the ceramics are appropriate, and the processing on the substrate 1, that is, the slit or V-groove processing may be either a mechanical processing or an etching method.

Metal thin film deposition can be performed with a positional accuracy on the order of microns by using a metal thin film deposition using a mask or an etching process using a resist. Here, as for the method of mounting each optical element, the optical element is mounted upright in the processed slit, and fixed between the substrate and the substrate using solder glass. The slit of the substrate 1 can be formed by processing on the order of microns or by using a plurality of substrates 1 and fixing the optical element between the substrates. Thereby, since the positional accuracy of the optical element can be adjusted on the order of microns, the optical flat element that reflects, combines, and branches light can be fixed at a high-precision angle. Further, since the solder glass is used for fixing the optical element, the coefficient of linear expansion is small, and the optical element substrate does not change even when the temperature and humidity change, so that stable optical characteristics can be obtained. The in-line optical isolator element is fixed by a V-groove or a similar groove as shown in FIG. The in-line type optical isolator 3 shown in FIG. 5 is one in which both sides of a Faraday rotator are laminated by a wedge-type birefringent polarizer, so that light in the forward direction passes for any polarized light and removes return light. It is. In this embodiment, the isolator is shaped into a cylindrical shape, but may be square. When a Faraday rotator having magnetism is used in advance as shown in this embodiment, a magnet for applying a magnetic field is not required.
The wedge-shaped fiber used for the connection with the pumping light source is a multimode fiber or a single-mode fiber whose core is enlarged by heating to form one end face of the fiber into a wedge shape. High-efficiency coupling can be achieved by adjusting the focus of the wedge lens and the focal position of the laser.

The input / output lens is composed of a small gradient index lens or a combination of an aspherical lens and a fiber. If the lens and the fiber are fixed by a V-groove or a similar groove on the substrate, positioning is easy. Configuration.

Next, the operation of the optical composite module according to the present invention will be described with reference to FIG. In FIG. 1, the signal light enters from an input port 24 on the left side in the figure. The light emitted from the lens is collimated and almost collimated,
The light enters the DM filter 23 plate and is transmitted. The excitation light emitted from the excitation light source is reflected by the WDM filter 23 and enters a rare-earth doped fiber (not shown) on the incident side. Therefore, this embodiment is of the backward pump type, and the incident signal light is an amplified signal light.

This embodiment corresponds to the module for backward excitation shown in FIG. The signal light transmitted through the WDM filter 23 enters an in-line optical isolator element,
To Penetrate. Thereafter, the light enters the branch element, and a part of the output light is reflected and transmitted by the incident-side end face. A part of the reflected light is incident on the output light monitoring PD, where it is photoelectrically converted and used for the excitation semiconductor laser drive feedback, the output light abnormality monitoring control circuit, etc. for the amplified light stable output. After passing through the branch element, the light enters the output side fiber via the output port side lens.

Further, the reflected return light from the output side fiber is also reflected on the output side reflection surface of the branch element, and is used for a detection circuit for abnormality monitoring of the output port side fiber line. In the embodiment shown in FIG. 1, the electronic circuit for driving the excitation light source and the electronic circuit for driving the light-receiving element may be integrally formed in the case.

FIG. 2 shows another embodiment of the present invention, in which an excitation light source, a multiplexing element, an in-line optical isolator element, a branch element, and a monitor are separated from each other. The configuration is such that it is not affected by the laser.

In both the embodiment of FIG. 1 and the embodiment of FIG. 2, since a semiconductor laser is mounted inside, dry helium gas
The outer periphery of the case must be sealed by seam welding, soldering, etc.

[0018]

According to the present invention as described above, the following effects can be obtained.

(1) All the light receiving / emitting elements and optical elements are mounted and fixed on one substrate, and the passive alignment method is used for fixing the optical elements, so that the adjustment can be easily performed.

(2) Since solder glass is used for fixing each optical element, the position of the optical element does not change due to environmental changes, characteristics are stable, and reliability is high.

(3) Since a semiconductor laser is built-in as an excitation light source, and the semiconductor laser and the optical element are mounted on one substrate, the light use efficiency is high and the optical fiber amplifier can be downsized.

(4) An excitation laser driving circuit and a light receiving element driving circuit can be built in. By integration including an electronic circuit,
The optical fiber amplifier can be significantly reduced in size.

(5) It can be manufactured in a short time and at low cost by a simple manufacturing process.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention in which a substrate with one electrode is provided on a Peltier element, and an excitation light source and a WD are provided on the substrate.
FIG. 5 is a layout view in which an M element, a branch element, an isolator element, and a light receiving element are mounted and fixed.

FIG. 2 shows a second embodiment of the present invention in which the substrate is an excitation light source;
FIG. 4 is a diagram showing that the heat radiation from the excitation light source is reduced by separating the substrate, which is divided into two parts, a DM element part, an isolator element, a branch element, and a light receiving element part.

FIG. 3 is a perspective view of the layout shown in FIG. 1;

FIG. 4 is a diagram illustrating functions of the optical composite module of the present invention, and is a diagram illustrating an optical composite module including a forward excitation unit and a backward excitation unit.

FIG. 5 is a diagram showing an in-line optical isolator element according to the present invention.

FIG. 6 is a configuration diagram in a case where a fiber and a lens are mounted on a substrate, in which a V-groove or a structure similar thereto is provided on the substrate, and the fiber lens is fixed by solder glass.

FIG. 7 is a diagram showing a connection structure between a semiconductor laser for excitation and a coupling lens according to the present invention.

FIG. 8 is a diagram illustrating the structure of a conventional optical composite module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Laser for excitation 3 Optical isolator element 4 Light receiving element 5 Lens for joining

Claims (7)

[Claims] 1. An optical composite module in which a Peltier element is provided in a storage case and a mounting board is fixed on the Peltier element, and a plurality of optical elements and light emitting and receiving are mounted on a mounting board made of silicon or ceramic. An optical composite module in which an element is arranged and the mounting substrate is divided into a light source mounting substrate on which a light emitting element is disposed and an optical element mounting substrate on which an optical element is disposed. 2. The optical composite module according to claim 1, wherein the light source mounting board and the optical element mounting board are integrally formed. 3. The optical composite module according to claim 1, wherein a groove for fixing an optical element is provided on the mounting substrate. 4. The optical composite module according to claim 1, wherein an optical element is bonded to an outer peripheral surface of said mounting board. 5. The optical composite module according to claim 1, wherein an optical isolator having a configuration in which the optical elements are stacked and integrated is used. 6. The optical composite module according to claim 1, wherein a wedge-shaped collimator lens is used at one end of the connection element of the light source mounting board. 7. The case for accommodating the mounting substrate has a butterfly type package structure.
3. The optical composite module according to claim 2.