JPH0832524A - Optical circuit module constituting fiber optical amplifier - Google Patents

Abstract

PURPOSE:To allow provision of a containing space processing for an excess length of an optical fiber enough to be one direction only by providing a 1st port, a 2nd port and a 3rd port to the same side of the optical circuit module so as to attain same input output directions of the three optical fibers. CONSTITUTION:Collimators 28, 30, 32 being ports are provided to an optical circuit module 10. These collimators 28, 30, and 32 are arranged side by side on one side of a case main body 34 at a proper interval, that is, on the same side of the case according to the design and the optical axes of them are made in parallel. The 2nd collimator 30 is provided to the left of the 1st collimator 28 and the 3rd collimator 32 is provided to the right of the 1st collimator 28. Since the input output direction of three optical fibers is the same, only one direction of an accommodating space to process an excess length of the optical fibers is enough. Thus, the accommodation performance of the optical fibers is improved. Thus, the size of the optical amplifier is miniaturized and the job efficiency is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical circuit module which constitutes a fiber optical amplifier.

[0002]

2. Description of the Related Art Conventionally, as an optical fiber amplifier, an erbium-doped fiber (hereinafter sometimes referred to as EDF) optical amplifier has been known (for example, reference: "optical amplifier and its application", Ohmsha, 1992). Year 100th
Pp.-111). This EDF optical amplifier is classified into a backward pumping type and a forward pumping type.

Recently, in order to downsize the EDF optical amplifier, a long wave pass filter (L
WPF), an isolator, and an optical circuit module in which the optical functions of a portion configured by a coupler are integrated are used. An example thereof is disclosed in the document "1992 IEICE Autumn Meeting Proceedings, C-222" (p4-244).

A configuration of a conventional backward pumping type optical circuit module will be briefly described. FIG. 3 is a simplified configuration diagram for explaining the configuration of a conventional optical circuit module. In the conventional optical circuit module 10, the excitation light 12 input from the first collimator 28 is reflected at a right angle by the LWPF 70, and then output from the second collimator 30 to output the EDF.
The first collimator 28, as input to (not shown),
The LWPF 70 and the second collimator 30 are arranged. The signal light 14 that has entered from the second collimator 30 travels in the direction opposite to the direction in which the excitation light 12 enters the second collimator 30. The signal light 14 incident from the second collimator 30 is L
After passing through the WPF 70, it passes through the isolator 26. Most of the signal light 14 that has passed through the isolator 26 passes through the coupler 58 and then the third collimator 32.
Output from In this way, the LWPF 70, the coupler 5
8. Arrange the third collimator 32. Also, the coupler 58
As a result, the signal light 14 that is partially reflected is incident on the monitor light receiving element 66.

When an optical amplifier is constructed using such an optical circuit module 10, it is necessary to process the extra length of the optical fiber in order to connect the optical circuit module and the EDF and to attach an external output connector. At this time, it is necessary to secure an allowable bending radius of the optical fiber in order to process the excess length of the optical fiber.

[0006]

In the conventional optical circuit module, the optical fibers are provided on the three sides of the rectangular case body. Therefore, the optical fibers are drawn out in three directions. It is necessary to provide spaces for processing the length in three directions, which hinders downsizing of the optical amplifier. Also, the accommodation of the optical fiber is poor,
There is a problem that the work efficiency of assembling the optical amplifier is reduced.

Further, since the excitation light and the signal light input to the optical circuit module are reflected once by the filter and then output, the optical element due to the angular deviation or axis deviation when the filter is fixed or when the filter expands or contracts due to temperature change is output. There is also a problem that coupling loss between the optical element and the optical fiber is increased.

Here, the problem of the conventional backward pumping type optical circuit module is shown, but the same problem also occurs in the forward pumping type optical circuit module.

Therefore, there has been a demand for an optical circuit module for an EDF optical amplifier which can be miniaturized and has excellent workability in assembly.

Further, an optical circuit module having a small coupling loss and high reliability has been desired.

[0011]

Therefore, according to the optical circuit module of the present invention, among the functions of inputting pumping light, outputting pumping light, inputting signal light, and outputting signal light, , A plurality of ports having any one function or a plurality of functions, and a reflection optical system for guiding pumping light from a port having a function of inputting pumping light to a port having a function of outputting pumping light, and inputting a signal light A reflection optical system that guides the signal light to the port that has the function of outputting the signal light from the port that has the function of It is equipped with an isolator that is provided in the optical path of the optical system and outputs the signal light to the port that has the function of passing the signal light and outputting the signal light. On one side, such that each optical axes of the respective input and output light of the excitation light and signal light are parallel, characterized in that is provided.

Further, in a preferred embodiment of the present invention, a reflection optical system for guiding pumping light from a port for inputting pumping light to a port for outputting pumping light and a signal for outputting a signal light from a port for inputting signal light are provided. It is preferable that the reflection optical system that guides light is configured by an optical element of a type in which the excitation light and the signal light are internally reflected at least twice.

In the embodiment of the present invention, preferably, the reflection optical system for guiding the signal light from the port for inputting the signal light to the port for outputting the signal light is composed of two optical elements, and an isolator is provided between these optical elements. Is good to place.

[0014]

According to this structure, since the pumping light input port, the signal light input port, the pumping light output port, and the signal light output port are provided on the same side of the optical circuit module, the light connected to these ports is connected. The fiber input and output directions are the same. Therefore, the accommodation space for processing the extra length of the optical fiber is only on one side of the optical circuit module, and the accommodation of the optical fiber is improved.

Further, when the first and second reflecting optical systems are composed of block-shaped optical elements of the type which reflect two or more even times, even if an angular deviation or an axial deviation of the optical elements occurs, these The light emitted from the optical element is only shifted in parallel. The relationship between the amount of deviation of the light beam and the coupling loss is loose with respect to the axis deviation of the optical element. Therefore, the angle of each block fixing the collimator or filter due to expansion and contraction due to temperature change, etc. Even if misalignment or axis misalignment occurs, the amount of light beam misalignment is small, and therefore the coupling loss is also small.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In these drawings, each component is only schematically shown so that the present invention can be understood,
Therefore, the shapes, dimensions, and arrangements of these constituent components are not limited to the illustrated examples.

FIG. 1 is a schematic configuration diagram for explaining a first embodiment of the configuration of an optical circuit module of the present invention. An amplifier having an optical circuit module configured as in this embodiment is called a backward pumping type.

This optical circuit module 10 has a pumping light 12
, Pumping light 12 is output, signal light 14 is input,
And a plurality of ports having any one function or a plurality of functions of outputting the signal light 14, that is, a first port 16, a second port 18, and a third port 20. In this embodiment, the first port 16 has a function of inputting the pumping light 12, the second port 18 has a function of outputting the pumping light 12 and inputting the signal light 14, and the third port 20 is a signal light. It has a function of outputting 14. Further, the module 10 includes a first reflection optical system 22 for guiding the pumping light 12 from a first port 16 having a function of inputting the pumping light 12 to a second port 18 having a function of outputting the pumping light 12, and a signal light. The second reflection optical system 24 for guiding the signal light 14 from the second port 18 having the function of inputting 14 to the third port 20 having the function of outputting the signal light 14, and the optical path of the second reflection optical system 24 are provided. , A third port 2 having a function of passing the signal light 14 and outputting the signal light 14
And an isolator 26 that outputs the signal light 14 to 0. In this embodiment, collimators 28, 30 and 32 are provided as the respective ports. The collimators 28, 30 and 32 are provided side by side on one side of the case body 34, that is, on the same side with a suitable interval according to the design so that their optical axes are parallel to each other.
Here, the first collimator 28 is centered, the second collimator 30 is provided on the left side of the first collimator 28, and the third collimator 32 is provided on the right side.
Is provided. Further, the first optical reflection system 22 is composed of block-shaped optical elements 36, and the second optical reflection system 24 is composed of block-shaped optical elements 38 and 40. In addition,
Hereinafter, the optical elements 36, 38, and 40 may be simply referred to as blocks. Also, these blocks 36, 38,
40 is made of a suitable transparent optical material, for example, glass or plastic having a low transmittance for signal light or excitation light. Alternatively, the optical element may be fixed by forming a hole in metal or the like. And in this embodiment, block 3
The isolator 26 is arranged in the optical path between 8 and 40. If necessary, another block-shaped optical element 42 is provided in the optical path between the isolator 26 and the block 40. The optical element 42 may also be simply referred to as a block.

The first collimator 28 passes through the optical fiber 44.
Input wavelength to optical circuit module 10 from 1.48 μm
The excitation light 12 in the band is reflected by the reflection mirror 50 formed on one surface of the block 36 and then reflected by the reflection mirror 52 formed on the other surface of the same block 36. The excitation light 12 reflected by the reflection mirror 52 passes through a short wave pass filter (hereinafter sometimes referred to as SWPF) 54 formed on one surface of the block 38,
The light is output from the second collimator 30 and input to the EDF (not shown) via the optical fiber 46. The SWPF 54 passes the 1.48 μm band that is the excitation light, but reflects the 1.55 μm band that is the signal light.

The signal light 14 having a wavelength band of 1.55 μm is EDF.
When input to (not shown), the signal light 14 is amplified by the EDF. In this case, the signal light 14 is the excitation light 12 E
Input to EDF from the direction opposite to the input to DF. The amplified signal light 14 travels in a direction opposite to the direction in which the pumping light 12 is input to the EDF via the common optical fiber 46, and is input from the second collimator 30 to the optical circuit module 10. Signal light 14 input to the optical circuit module 10
Is the SWPF5 formed on one surface of the block 38.
After being reflected by 4, the light is reflected by the reflection mirror 56 formed on the other surface of the same block 38 and advances in the direction perpendicular to the input direction to the optical circuit module 10. Reflection mirror 5
The signal light 14 reflected by 6 passes through the isolator 26. The isolator 26 allows light to pass in one direction and blocks light from passing in the opposite direction, thus preventing oscillation caused by reflection of optical components in the optical amplifier. In this embodiment, the isolator 26 allows light to pass in the direction of arrow a. The signal light 14 that has passed through the isolator 26 is partially branched by the coupler 58 formed on one surface of the block 42. For example, it is branched into 10: 1 by using the coupler 58. Most of the signal light 14 passing through the coupler 58 is reflected by the reflection mirror 62 formed on one surface of the block 40 and then reflected by the reflection mirror 64 formed on the other surface of the same block 40. Output from the 3 collimator 32. In this way, each collimator 28, 30, 32
The input and output lights in the optical circuit module 10 are parallel to the. On the other hand, the signal light 14 reflected by the coupler 58
After being reflected by the reflection mirror 60 formed on the other surface of the block 42, is input to the monitor light receiving element 66, is electrically changed, and is output as a monitor output. The reflection mirrors 50, 52, 56, 60, 62, 6 used in this embodiment.
4, SWPF 54, and coupler 58 are formed of a dielectric film.

FIG. 2 is a schematic configuration diagram for explaining the second embodiment of the configuration of the optical circuit module of the present invention. An amplifier having an optical circuit module configured as in this embodiment is called a forward pump type.

The configuration of this forward pumping type optical circuit module differs from the backward pumping type optical circuit module described above in the following points. That is, the isolator 26 provided in the optical path of the second reflective optical system 24 transmits light in the opposite direction, and the blocks 42 are arranged in different directions. In the forward pumping type, the signal light 14 is input to the third port 20, that is, the third collimator 32, and is output from the second port 18, that is, the second collimator 30.

Also in this embodiment, the pumping light 12 input to the optical circuit module from the first collimator 28 via the optical fiber 44 is output from the second collimator 30 after passing through the first reflecting optical system 22, E via fiber 46
Input to DF (not shown).

Further, in this embodiment, the signal light 14 is input to the optical circuit module 10 from the third collimator 32 via the optical fiber 48. The signal light 14 input to the optical circuit module 10 is reflected by the reflection mirror 64 formed on one surface of the block 40, and then reflected by the reflection mirror 62 formed on the other surface of the same block 40, and the optical circuit It proceeds in a direction perpendicular to the input direction to the module 10. The signal light 14 reflected by the reflection mirror 62 is partly branched by the coupler 58 formed on one surface of the block 42. Most of the signal light 14 passing through the coupler 58 passes through the isolator 26. In this embodiment, the isolator 26
Transmits light in the direction of arrow b. The signal light 14 that has passed through the isolator 26 is reflected by a reflection mirror 56 formed on one surface of the block 38, and then the same block 3
It is reflected by the SWPF 54 formed on the other surface of 8, and is output from the second collimator 30 and passed through the optical fiber 46 to E
Input to DF (not shown). In this way, the optical circuit module 1 for each collimator 28, 30, 32 is provided.
The input and output lights within 0 are parallel. Signal light 14 is E
When input to the DF (not shown), the signal light 14 is amplified by the EDF. On the other hand, the signal light 1 reflected by the coupler 58
4 is reflected by the reflection mirror 60 formed on the other surface of the block 42, and then input to the monitor light receiving element 66,
It is electrically changed and output as a monitor output.

As can be understood from the first and second embodiments, the first collimator 28 is used in the present invention.
The second collimator 30 and the third collimator 32 are provided on the same side with respect to the optical circuit module so that the optical axes of the input light and the output light of the excitation light and the signal light are parallel to each other. In addition, the signal light or the excitation light is reflected twice inside each block.

Obviously, the present invention is not limited to the above embodiments. For example, in each of the above-described embodiments, the wavelength of 1.48 μm band is used as the excitation light, but other than that, for example, 0.98 μm band may be used.

[0027]

As is apparent from the above description, according to the optical circuit module of the present invention, since the input and output directions of the three optical fibers are the same, the accommodation space for processing the surplus length of the optical fibers. Is only in one direction. Also, the accommodation of the optical fiber is improved. Therefore, the size of the optical amplifier can be reduced, and the workability of assembling the optical amplifier can be improved.

Further, when the first and second reflecting optical systems are constituted by block type optical elements of the type which reflect two or more even times, even if an angular deviation or axis deviation of the optical elements occurs, these The light emitted from the optical element is only shifted in parallel. The relationship between the amount of deviation of the light beam and the coupling loss is loose with respect to the axis deviation of the optical element. Therefore, the angle of each block fixing the collimator or filter due to expansion and contraction due to temperature change, etc. Even if misalignment or axis misalignment occurs, the amount of light beam misalignment is small, so that it is possible to provide a highly reliable optical circuit module with little increase in coupling loss.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the configuration of an optical circuit module of the present invention.

FIG. 2 is a schematic configuration diagram showing a second embodiment of the configuration of the optical circuit module of the present invention.

FIG. 3 is a schematic configuration diagram for explaining a configuration of a conventional optical circuit module.

[Explanation of symbols]

 10: Optical circuit module 12: Excitation light 14: Signal light 16: First port 18: Second port 20: Third port 22: First reflection optical system 24: Second reflection optical system 26: Isolator 28: First collimator 30: 2nd collimator 32: 3rd collimator 34: Case main body 36, 38, 40, 42: Block 44, 46, 48: Optical fiber 50, 52, 56, 60, 62, 64: Reflection mirror 54: SWPF 58: Coupler 66: Light receiving element for monitor

Claims (3)

[Claims] 1. In an optical circuit module constituting a fiber optical amplifier, any one function of pumping light input, pumping light output, signal light input, and signal light output is provided. Alternatively, it has a plurality of ports having a plurality of functions, a first reflection optical system that guides pumping light from a port having a function of inputting pumping light to a port having a function of outputting pumping light, and a function of inputting signal light. A second reflective optical system that guides the signal light to the port that has the function of outputting the signal light, and a function that is provided in the optical path of the second reflective optical system and that passes the signal light and outputs the signal light. With an isolator that outputs signal light to the ports, all the ports on the same side with respect to the optical circuit module,
The optical circuit module is provided such that the optical axes of the input light and the output light of the pumping light and the signal light are parallel to each other. 2. The optical circuit module according to claim 1, wherein the first reflective optical system and the second reflective optical system are
An optical circuit module comprising a block-shaped optical element of a type that reflects two or more even times. 3. The optical circuit module according to claim 2, wherein the second reflective optical system is composed of two optical elements, and the isolator is arranged between these optical elements. Circuit module.