JP2003069504A - Wavelength management module and wavelength management apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a wavelength management apparatus by employing a wavelength selection means so as to maintain an oscillation wavelength from a light source at a predetermined wavelength for use. SOLUTION: There are provided a waveguide-type optical branching means 111 having functions of making signal light oscillated from a light source 1 branch into main signal light S and monitoring signal light M, and making the monitoring signal light M branch into first branching signal light M1 and second branching signal light M2, a first measurement means 15 which measures light intensity of the first branching signal light M1, and a second measurement means 17 which measures light intensity of the second branching signal light M2. Further, a wavelength selection means 14 having wavelength-dependent transmittance is provided on an optical path of the first branching signal light M1. The first measurement means 15 measures the light intensity transmitted through the wavelength selection means 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength management module and a wavelength management device for controlling the oscillation wavelength of a light source so as to keep it at a preset use wavelength, and more particularly to a wavelength management module using a waveguide type optical branching means. Is.

[0002]

2. Description of the Related Art In a wavelength division multiplexing system (hereinafter referred to as WDM system), signal lights of a plurality of wavelengths are used.
As the used wavelength spacing becomes higher, the adjacent wavelength spacing becomes smaller. A semiconductor laser (LD) is generally used as a light source in the WDM system, but the LD causes a change in center wavelength of emitted light due to a change with time or an environment, which causes crosstalk with adjacent wavelengths. Interference may occur. Therefore, in order to keep the oscillation wavelength of the LD constant, for example, a wavelength management device using a wavelength selection means such as an optical resonator or a short-period fiber grating whose transmission characteristic has wavelength dependency is used.

FIG. 15 is a schematic configuration diagram showing an example in which a wavelength management device is configured by using an optical resonator as a wavelength selection means. In this figure, reference numeral 1 is an LD light source, and 11 is a wavelength management module. LD light source 1 is the temperature of the chip or L
The oscillation wavelength can be controlled by controlling the D introduction current, and in the former case, a temperature controller (not shown) is provided. The light emitted from the LD light source 1 is split into two by the first coupler 2. By the first coupler 2, for example, 95% of the emitted light is made incident on the optical fiber for transmission as the main signal light, and the remaining 5% is made incident on the wavelength management module 11 as the signal light for monitoring. In the wavelength management module 11, first the collimator 12
Then, the monitor signal light is incident on the half mirror 13 as parallel light. The transmitted light of the half mirror 13 is an optical resonator 14
The intensity of the light transmitted through the optical resonator 14 is measured by the first photodiode 15. On the other hand, the reflected light from the half mirror 13 passes through the reflecting mirror 16 and the second photodiode 17
And the light intensity is measured. Generally, the collimator 12, the half mirror 13, the optical resonator 14, the first photo diode 15, the reflection mirror 16, the second photo diode 17, etc., which compose the wavelength management module 11, collectively accommodate them. It is fixed to the board or housing.

FIG. 16 is a sectional view of an example of the optical resonator 14 seen from above. In the optical resonator 14 of this example, two substrates 21, 21 ′ having reflection films 21 a, 21 b having a predetermined reflectance on one surface face each other with the reflection films 21 a, 21 b sandwiching the medium 22. And the spacers 23 are arranged between the two substrates 21 and 21 'so that the length d between the substrates 21 and 21' (hereinafter, also referred to as a gap length) d is a predetermined length. It is configured to be In this example, the medium 22 is an air layer. The light transmittance of the optical resonator 14 has wavelength dependency,
For example, it has a wavelength-transmittance characteristic close to a sine wave as shown in FIG. Therefore, if the wavelength of the monitor signal light incident on the optical resonator 14 is constant, the transmitted light intensity measured by the first photodiode 15 is constant, and the wavelength of the monitor signal light changes. If it occurs, the change appears in the transmitted light intensity measured by the first photodiode 15.

The intensity of the light emitted from the LD light source 1 may change with time. In this case, the intensity of the transmitted light measured by the first photodiode 15 is constant even if the wavelength of the emitted light is constant. Will change. Regarding this, since the value of the reflected light intensity of the half mirror 13 measured by the second photodiode 17 changes in accordance with the change of the emitted light intensity of the LD light source 1, the light measured by the first photodiode is changed. If the difference between the intensity value and the value of the light intensity measured by the second photodiode 17 is calculated, then the amount of change in the transmitted light intensity measured by the first photodiode 15 The change amount of the transmitted light intensity due to the change of the emitted light intensity is offset, and the change amount of the transmitted light intensity due to the change of the wavelength of the emitted light is found. Then, based on the amount of change in transmitted light intensity after this arithmetic processing,
The LD light source 1 is designed so that the wavelength of the emitted light is returned to the original, that is, the amount of change in the transmitted light intensity after the arithmetic processing becomes zero.
Temperature controller or LD introduction current is controlled. In the figure, reference numeral 5 indicates a computing device, and 6 indicates a control device. Reference numeral 18 in the figure is a temperature sensor, which is provided as necessary. The temperature sensor 18 detects a temperature change in the optical resonator 14 and is provided with a circuit (not shown) for performing temperature compensation based on the detection result.

FIG. 18 is a schematic configuration diagram showing a conventional example in which a wavelength management device is configured by using a short period fiber grating as a wavelength selection means. In this figure, the same components as those in FIG. 15 are designated by the same reference numerals and the description thereof is omitted. In the wavelength management device of this example, the light emitted from the LD light source 1 is split into two by the first coupler 2. With this first coupler 2, for example, 95% of the emitted light
Is incident on the optical fiber for transmission as the main signal light, and the remaining 5% is sent to the second coupler 21 as the signal light for monitoring, and is divided into the first branch signal light and the second branch signal light. Branched. The first emission port 21a of the second coupler 21
Is connected to one end of the short-period fiber grating 24, and the other end of the short-period fiber grating 24 is connected to the first photodiode 25. On the other hand, the second emission port 21b of the second coupler 21 is connected to the second photodiode 26. Then, the second coupler 21
The first branched signal light of the branched light split into two is incident on the short-period fiber grating 24, and the transmitted light intensity transmitted through the short-period fiber grating 24 is measured by the first photodiode 25. The intensity of the second branched signal light is measured by the second photodiode 26.

The short-period fiber grating 24 is a fiber grating in which the refractive index of the optical fiber core is periodically changed, and in particular, the short-period fiber refractive index change period of 1 μm or less. Short period fiber grating 2
No. 4 has a characteristic of selectively reflecting light in a specific wavelength band, and has, for example, a reflectance-wavelength characteristic as shown in FIG. Therefore, the transmittance-wavelength characteristic of this short-period fiber grating 24 is shown in FIG.
It is represented by a graph having a substantially V shape in a specific wavelength band as shown in (b). Therefore, the wavelength of the monitor signal light incident on the short-period fiber grating 24 is
If the wavelength of the monitor signal light is constant when the transmittance-wavelength characteristic graph is in the range of the specific wavelength band having a substantially V shape, the transmitted light intensity measured by the first photodiode 25. Is constant, and when a change occurs in the wavelength of the monitor signal light, it appears as a change in the transmitted light intensity measured by the first photodiode 25.

Regarding the change with time of the emitted light intensity of the LD light source 1, the value obtained by measuring the light intensity of the second branched signal light with the second photodiode 26 is the change of the emitted light intensity of the LD light source 1. The first photodiode 25
If the arithmetic processing is performed so as to obtain the difference between the value of the light intensity measured by the second photo diode and the value of the light intensity measured by the second photo diode, the transmitted light intensity measured by the first photo diode 15 is calculated. Among the change amounts, the change amount of the transmitted light intensity due to the change of the emitted light intensity in the LD light source 1 is offset, and the change amount of the transmitted light intensity due to the change of the wavelength of the emitted light is found. Then, on the basis of the change amount of the transmitted light intensity after the arithmetic processing, the wavelength of the emitted light is returned to the original, that is, the change amount of the transmitted light intensity after the arithmetic process becomes zero. Control the temperature controller or LD introduction current.

Further, as shown in FIGS. 20 and 21,
Of the two optical paths branched by the first coupler 2a,
There may be a case where a device having polarization dependence such as an LN modulator (lithium niobate intensity or phase modulator) 20 is provided on the optical path of the main signal light. In this case, the first coupler 2a is polarized. The optical fiber 2b on the incident side and the optical fibers 2c, 2d on the output side are both polarization-maintaining optical fibers having the characteristic of preserving the polarization plane. 20 and 21, the same components as those in FIGS. 15 and 18 are designated by the same reference numerals, and description thereof will be omitted.

[0010]

However, in such a conventional module and device for wavelength management, there is a problem that miniaturization is difficult to achieve. That is, in the wavelength management module 11 using the optical resonator 14, the monitor signal light emitted from the collimator 12 is branched into two, and the respective branched lights are divided into the first and second photodiodes 15, 15. Since the optical path until the light is received by 17 is formed in the space, it is necessary to secure the distance between the components so that the components in the wavelength management module 11 do not come into contact with the optical path and cause a hindrance. Therefore, there is a problem that it is difficult to arrange each component in high density and it is difficult to miniaturize the module.

Further, the short period fiber grating 24
In the wavelength management device using the
Since the two optical couplers 2 and 21 and the short-period fiber grating 24 are connected before reaching the photodiode 25, there is a problem that the optical path becomes relatively long. For example, the length of one optical fiber coupler is generally around 5 cm, and an extra length for fusion splicing is also required. Therefore, from the LD light source 1 to the first photodiode 25.
The distance including up to was at least about 20 cm, and it was impossible to reduce the size further.

Further, in order to perform wavelength management in a system including a device having polarization dependence as described above, the first coupler 2a was composed of a polarization maintaining coupler. Most of is emitted as the main signal light,
A polarization maintaining coupler having a function of emitting the rest as signal light for monitoring has a problem that it is very expensive because it is difficult to manufacture and the yield is low. For example, if the first coupler 2a is manufactured using a polarization maintaining optical fiber, the price is 50 times or more that of a coupler manufactured using an optical fiber that does not have a polarization maintaining characteristic, and the wavelength is There is an inconvenience that the cost for management increases significantly.

The present invention has been made in view of the above circumstances, and makes it possible to miniaturize a wavelength management device for maintaining an oscillation wavelength of a light source at a preset use wavelength by using a wavelength selection means. An object of the present invention is to reduce the cost of wavelength management in a system including a device having polarization dependence.

[0014]

The present invention solves at least one of the above-mentioned problems, and a wavelength management module of the present invention controls a wavelength of a light source so as to keep the oscillation wavelength at a preset operating wavelength. In the management module, the signal light oscillated from the light source is split into a main signal light and a monitor signal light, and the monitor signal light is divided into a first branch signal light and a second branch signal light. And a waveguide type optical branching unit having a function of branching into at least one of the optical path of the first branched signal light and the optical path of the second branched signal light, the transmittance of which has wavelength dependency. Wavelength selecting means having
The wavelength selecting means comprises: first measuring means provided on the optical path of the first branched signal light; and second measuring means provided on the optical path of the second branched signal light. The measuring means on the optical path provided with, receives the reflected light or transmitted light of the wavelength selection means and measures the light intensity thereof,
The measuring means on the optical path not provided with the wavelength selecting means receives the branched signal light emitted from the waveguide type optical branching means and measures its light intensity.

Alternatively, it is a wavelength management module for controlling the oscillation wavelength of the light source so as to maintain it at a preset use wavelength, and splits the signal light emitted from the light source into a main signal light and a monitor signal light. A waveguide type optical branching means having a function, a wavelength selecting means having a transmittance having wavelength dependency and on which the monitor signal light is incident, and a reflected light or a transmitted light of the wavelength selecting means for receiving and And a third measuring means for measuring the light intensity.

As the wavelength selecting means, two substrates, one surface of which is a reflecting surface having a predetermined reflectance, are arranged substantially in parallel so that the reflecting surfaces face each other with the medium sandwiched therebetween. Can be used. In this case, a collimator may be provided as an incident means to the optical resonator, if necessary. Alternatively, a bandpass filter using a dielectric multilayer film can be used as the wavelength selecting means. In this case, if necessary, a collimator may be provided as an incident means for the bandpass filter. The wavelength selecting means may be provided on the waveguide type optical branching means.

A short period fiber grating can be used as the wavelength selecting means. In this case, it is preferable that the light emitted from the waveguide type optical branching means is made incident on the short period fiber grating through the optical fiber. Alternatively, a short-period grating can be formed as a wavelength selecting means on the waveguide type optical branching means.

Signal light oscillated from the light source is incident on the waveguide type optical branching means via a polarization maintaining optical fiber,
A polarization maintaining optical fiber may be connected to the emission end of the main signal light in the waveguide type optical branching means. In this case, it is preferable to provide a polarizer on the optical path before the signal light oscillated from the light source is incident on the waveguide type optical branching means.

The wavelength control device of the present invention comprises the wavelength control module of the present invention. When the wavelength control device of the present invention has the first measuring means and the second measuring means, the first measuring means is used. Calculating means for obtaining the difference between the light intensity measured by the second measuring means and the light intensity measured by the second measuring means, and controlling the oscillation wavelength of the light source so that the difference in the light intensity becomes a predetermined value. A control means is provided. Alternatively, when the wavelength management module has the third measuring means,
Control means is provided for controlling the oscillation wavelength of the light source so that the light intensity measured by the third measuring means has a predetermined value.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
FIG. 1 is a schematic configuration diagram showing a first embodiment of a wavelength management device of the present invention. Reference numeral 110 in the figure denotes a wavelength management module. In FIG. 1, the same components as those in FIG. 15 are designated by the same reference numerals and the description thereof will be omitted. The wavelength management module 110 of the present embodiment splits the signal light oscillated from the light source 1 into the main signal light S and the monitor signal light M, and the monitor signal light M into the first branch signal light. M1 and second
It is equipped with a waveguide type optical branching means 111 having a function of branching to the branched signal light M2. Further, the optical resonator 14 is used as the wavelength selecting means.

The waveguide type optical branching means 111 has the structure shown in FIG.
An optical waveguide 111 having two branches as shown in FIG.
a is formed. The waveguide type optical branching means 111 is preferably manufactured by a method of forming an optical waveguide 111a by irradiating a substrate made of silica glass with ultraviolet rays to change the refractive index. In this embodiment, the light intensity ratio between the main signal light S and the monitor signal light M is S: M = 95:
5 and the light intensity ratio of the first branch signal light M1 and the second branch signal light M2 is M1: M2 = 66: 33.

Optical fibers 120 and 1 are provided at the incident end of the waveguide type optical branching means 111 and the emitting end of the main signal light S, respectively.
21 is connected. At the connecting portion between the waveguide type optical branching means 111 and the optical fibers 120 and 121, the end portions of the optical fibers 120 and 121 are, as shown in FIG.
The end face of the optical fiber 120 (121) and the block body 1 are provided in the block body 122 having one V groove 125 inside.
It is held so that the end face of 22 is flush with the end face. Then, the optical fibers 120 and 121 and the block body 1
By bonding the end face of 22 to the end face of the waveguide type optical branching means 111 using an ultraviolet curing adhesive, the optical fibers 120 are respectively provided at the incident end of the waveguide type optical branching means 111 and the emitting end of the main signal light S. , 121 are connected.
In the present embodiment, the block body 122 has a structure shown in FIG.
As shown in FIG. 3, a plate-shaped upper block 124 made of glass is laminated on a rectangular parallelepiped lower block 123 made of glass or ZrO _2.
V groove 125 is formed on the upper surface of the. Optical fiber 12
The ends of 0 and 121 are the inner surface of the V groove 125 and the upper block 1.
It is held so as to be sandwiched by the lower surface of 24.

The first branched signal light M1 emitted from the waveguide type optical branching means 111 is collimated by a collimator lens (collimator) 112 provided on the optical path of the signal light M1 and then optically resonated. It is configured to be incident on the container 14. The transmitted light that has passed through the optical resonator 14 and is emitted is incident on the first photodiode (first measuring means) 15 via the condenser lens 15a, and the light intensity thereof is measured. It should be noted that the condenser lens 15a may be provided if necessary, and may be configured without it.
On the other hand, the second branched signal light M2 emitted from the waveguide type optical branching means 111 is incident on the second photodiode (second measuring means) 17 and the light intensity thereof is measured. In addition,
In order to improve the efficiency of incidence on the second photodiode 17, a condenser means such as a condenser lens may be provided between the emission end of the waveguide type optical branching means 111 and the second photodiode 17 as necessary. It may be provided. In the present embodiment, the waveguide type optical branching means 111, the collimator lens 112, the optical resonator 14, the first photo diode 15, and the second photo diode 17 which compose the wavelength management module 110 are not shown. , Are fixed to a board or a housing that collectively accommodates them.

Then, the arithmetic unit 5 performs arithmetic processing so as to obtain the difference between the value of the light intensity measured by the first photodiode 15 and the value of the light intensity measured by the second photodiode 17. Then, the controller 6 controls the temperature controller of the LD light source 1 or the LD introduction current so that the difference between the light intensities is always the predetermined value α, so that the oscillation wavelength of the light source 1 is set in advance. Can be kept at the wavelength. Here, the predetermined value α is obtained when the oscillation wavelength of the LD light source 1 matches a preset use wavelength,
The value corresponds to the difference between the value of the light intensity measured by the first photodiode 15 and the value of the light intensity measured by the second photodiode 17, and is set to, for example, substantially zero.
This α may be a value other than substantially zero, but if α is substantially zero, it is measured by the first photodiode 15 when the oscillation wavelength of the LD light source 1 matches a preset use wavelength. Since the wavelength management module 110 may be designed so that the value of the light intensity of the second photodiode 17 and the value of the light intensity measured by the second photodiode 17 are equal, there is an advantage that the design is easy.

According to this embodiment, the signal light emitted from the light source 1 is converted into the main signal light S, the first branched signal light M1 and the second signal light M1.
Since the optical branching of the branched signal light M2 into three is performed on one waveguide type optical branching means 111, it is necessary for the optical branching as compared with the conventional configuration in which the optical branching is performed in the space. The space is small and the wavelength management module 110 can be downsized. For example, in the conventional configuration shown in FIG. 15, the size of the housing required to house the components of the wavelength management module 11 is, for example, 15 mm in length and 50 m in width.
While the height is 8 mm and the volume is 6000 mm ³ , by changing the configuration of the present embodiment, the size of the housing that houses the components of the wavelength management module 110 is, for example, 10 mm in the vertical direction, The size can be reduced to 3200 mm ³ with a width of 40 mm and a height of 8 mm.

Further, in the conventional structure in which the light is split in the space, it is relatively difficult to manufacture and adjust the collimator, and the wavelength management module 11 requires skill in arranging and assembling the half mirror 13, the reflection mirror 16 and the like. However, the wavelength management module 110 of the present embodiment can apply the already established mass production technique to the production of the waveguide type optical branching means 111.
Further, since the collimator lens 112, the optical resonator 14, the first photo diode 15, and the second photo diode 17 are relatively easily arranged, mass production is possible and cost reduction can be achieved. Furthermore, in recent years, various optical modules have been increasingly integrated and multifunctional using a planar optical waveguide. In this embodiment, the waveguide type optical branching means 1 is used.
Since 11 is used, it is possible to support integration and multi-functionalization in the wavelength management module in the future. Also,
In this embodiment, the V-shaped groove 125 is used to optically connect the optical fibers 120 and 121 and the waveguide type optical branching means 111.
Since the block body 122 provided with is used, the optical fibers 120 and 121 and the waveguide type optical branching means 111 can be easily connected with good reproducibility, which is preferable for mass production. Furthermore, in the present embodiment, since the optical resonator is used as the wavelength selection means, it is possible to perform wavelength management for oscillation light of a plurality of wavelengths, and to obtain a wavelength management module capable of supporting multiple wavelengths. .

FIG. 2 is a schematic configuration diagram showing a second embodiment of the wavelength management device of the present invention. Reference numeral 210 in the figure denotes a wavelength management module. 2, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The wavelength management module 210 of the present embodiment is largely different from the wavelength management module 110 of the first embodiment in that the monitoring signal light M is emitted without being branched, and the second photodiode 17 is provided. It is not provided, and the arithmetic unit 5 is not provided.

In this embodiment, an optical waveguide 211a having one branch is formed in the waveguide type optical branching means 211 as shown in FIG. 2, and the main signal light S and the monitor signal light M are separated from each other. The light intensity ratio is S: M = 95: 5. Then, the waveguide type optical branching means 211
The monitor signal light M emitted from is collimated by the collimator lens 112 provided on the optical path of the signal light M, and then is incident on the optical resonator 14 so that the optical resonator 1
The transmitted light intensity of No. 4 is measured by the first photodiode (third measuring means) 15. In the present embodiment as well, the condenser lens 15a at the front stage of the first photodiode 15 may be provided if necessary, and may be configured without it.

In the present embodiment, the value of the light intensity after the monitor signal light M has passed through the optical resonator 14 is measured by the first photodiode 15. The measured light intensity value is previously measured. By controlling the oscillation wavelength of the light source 1 by the control device 6 so that the predetermined value β is set, the light source 1
The oscillation wavelength of can be maintained at a preset use wavelength. Here, the above-mentioned predetermined value β is obtained when the oscillation wavelength of the LD light source 1 matches the preset use wavelength,
Although it corresponds to the value of the light intensity measured by the first photodiode 15, the optical resonator 14 (wavelength selection means) has, for example, the configuration shown in FIG.
In the case of having the transmission characteristic as shown in, the value of the light intensity at the transmittance of 50% can be set to β. The predetermined value β can be set to a value of the light intensity when the transmittance is other than 50%, but in this example, the vicinity of the transmittance of 50% is
Since the slope of the graph showing the transmittance-wavelength characteristics is the largest, it is preferable to set the transmittance value in this region to β because the sensitivity to the fluctuation of the oscillation wavelength of the light source 1 becomes high.

According to the present embodiment, the monitor signal light M is used for measurement (first branch signal light M1) and reference (second branch signal light M2) as in the first embodiment. Although the accuracy is slightly inferior to the configuration in which the light intensity is different between the two branched lights, the wavelength management of the light source 1 can be performed with a simple device configuration, and the number of parts is small. Therefore, the wavelength management device can be provided at low cost. Further, in the present embodiment, as in the first embodiment, the wavelength management module can be advantageously downsized, mass-produced, integrated, and multifunctional as compared with the conventional configuration in which optical branching is performed in space. In addition to the effect that it can be achieved, since the signal light emitted from the light source 1 is branched only once, the waveguide type optical branching means 211 for performing the optical branching can be made smaller than in the first embodiment. The wavelength management module 210 can be made smaller.

FIG. 4 is a schematic configuration diagram showing a third embodiment of the wavelength management device of the present invention. Reference numeral 310 in the figure indicates a wavelength management module. 4, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The wavelength management module 310 of this embodiment is largely different from the wavelength management module 110 of the first embodiment in that the second branched signal light M2 emitted from the waveguide type optical branching means 111 is the second light. The second collimating lens 312 and the second optical resonator 314 are provided on the optical path until the light is received by the diode 17. In the present embodiment, the collimator lens and the optical resonator provided on the optical path of the first branched signal light M1 emitted from the waveguide type optical branching means 111 are, for convenience, the first collimator lens 112 and the first collimator lens 112, respectively. The optical resonator 14 of FIG.

In this embodiment, the first branch signal light M
When the first optical resonator 14 provided on the first optical path has a transmission characteristic as shown by the solid line in FIG. 5, for example, the second optical resonator provided on the optical path of the second branched signal light M2. Three
An optical resonator having a transmission characteristic as shown by a broken line in FIG. 5 is used as 14. That is, the second optical resonator 3
The transmission characteristic of 14 is obtained by changing the waveform representing the transmission characteristic of the first optical resonator 14 to 1/2 of FSR (free spectrum range).
It is represented by a waveform shifted only to the short wavelength side (or the long wavelength side).

In the present embodiment, the first branched signal light M1 emitted from the waveguide type optical branching means 111 is collimated by the first collimator lens 112, and then is directed to the first optical resonator 14. It is configured to be incident.
Then, the intensity of the transmitted light which is transmitted through the optical resonator 14 and is emitted is the first photodiode 15 through the condenser lens 15a.
Measured at. On the other hand, the second branched signal light M2 emitted from the waveguide type optical branching means 111 is configured to be collimated by the second collimator lens 312 and then incident on the second optical resonator 314. Has been done. Then, the intensity of the transmitted light that is emitted after passing through the optical resonator 314 is measured by the second photodiode 17 via the condenser lens 17a. It should be noted that the condenser lenses 15a and 17a may be provided if necessary, and may be configured without them.
Also in this embodiment, the waveguide type optical branching means 111, the first and second collimating lenses 112 and 312, the first and second optical resonators 14 and 314, and the first and second optical resonators which configure the wavelength management module 310. 2 photo diodes 1
Although not shown, 5 and 17 are fixed to a board or a housing that collectively accommodates them.

Then, the arithmetic unit 5 performs arithmetic processing so as to obtain the difference between the value of the light intensity measured by the first photodiode 15 and the value of the light intensity measured by the second photodiode 17. Then, the control device 6 controls the temperature controller of the LD light source 1 or the LD introduction current so that the difference between the light intensities is almost zero, so that the oscillation wavelength of the light source 1 is set to a preset use wavelength. Can be kept.

According to the present embodiment, as in the first embodiment, the wavelength management module 310 is downsized, mass-produced, integrated, and more versatile than the conventional configuration in which the optical branching is performed in the space. In addition to the effect that the functionalization can be achieved advantageously, in particular, the first and second optical resonators 14 and 314 are provided on the optical paths of both the first and second branched signal lights M1 and M2, respectively. By providing, the response characteristics can be further improved.

Next, a fourth embodiment of the wavelength control device of the present invention will be described. The wavelength management device of this embodiment uses a bandpass filter as the wavelength selection means. The wavelength management device of the present embodiment has a configuration in which a bandpass filter 414 is arranged instead of the optical resonator 14 in the first embodiment shown in FIG. Also in the present embodiment, the bandpass filter 414 and the first photodiode 1
5, and between the emission end of the waveguide type light branching means 111 and the second photodiode 17, a condenser means such as a condenser lens is provided as necessary.

Bandpass filter 4 in this embodiment
As the element 14, for example, as shown in FIG. 6, an element having a transmission characteristic of selectively transmitting light in a specific wavelength band and changing the transmittance in the specific wavelength band depending on the wavelength is used. Specifically, for example, a dielectric multilayer film formed by laminating a large number of thin films made of silica (SiO ₂ ), titania (TiO ₂ ), tantalum pentoxide (Ta ₂ O ₅ ) and the like on a substrate such as quartz glass. A filter is used. The transmission characteristics of the dielectric multilayer filter can be controlled by changing the refractive index of the material, the film thickness, and the number of layers.

In this embodiment, the first branched signal light M1 emitted from the waveguide type optical branching means 111 is collimated by the collimator lens 112 and then incident on the bandpass filter 414. Then, the intensity of the transmitted light which is transmitted through the bandpass filter 414 and is emitted is measured by the first photodiode (first measuring means) 15. On the other hand, the second branched signal light M2 emitted from the waveguide type optical branching means 111 is directly incident on the second photodiode (second measuring means) 17 and its light intensity is measured. Then, as in the first embodiment, the arithmetic device 5 causes the first
Calculation is performed so as to take the difference between the value of the light intensity measured by the photodiode 15 and the value of the light intensity measured by the second photodiode 17, and the difference in the light intensity is always a predetermined value. The oscillation wavelength of the light source 1 can be maintained at a preset use wavelength by controlling the temperature controller of the LD light source 1 or the LD introduction current by the control device 6 so as to be α (preferably approximately zero). .

According to the present embodiment, as in the first embodiment, it is advantageous to make the wavelength management module compact, mass-produced, integrated, and multifunctional, as compared with the configuration in which the optical branching is performed in the space. In addition to the effect that can be achieved, in particular, since a bandpass filter is used as the wavelength selection means, if the substrate is made thin, the size is considerably smaller than that of the optical resonator type. Further, it is suitable for performing wavelength management for a single wavelength, and wavelength control accuracy is good.

Next explained is the fifth embodiment of the wavelength control device of the invention. The wavelength management apparatus of this embodiment has a configuration in which a bandpass filter 414 is arranged instead of the optical resonator 14 in the second embodiment shown in FIG. As the bandpass filter 414 in the present embodiment,
Similar to the fourth embodiment, for example, a dielectric multilayer filter having a transmission characteristic as shown in FIG. 6 is used.
Also in the present embodiment, a condensing unit such as a condensing lens 15a is provided between the bandpass filter 414 and the first photodiode 15 as needed.

In the present embodiment, the signal light incident on the waveguide type optical branching means 211 is split into the main signal light S and the monitor signal light M. Waveguide type optical branching means 21
The monitor signal light M emitted from the beam splitter 1 is collimated by the collimator lens 112, and then enters the bandpass filter 414.
The transmitted light intensity of the first photodiode (third measuring means)
Measured at 15. Then, as in the second embodiment, the oscillation wavelength of the light source 1 is controlled by the control device 6 so that the value of the light intensity measured by the first photodiode becomes a predetermined value β set in advance. By controlling, the oscillation wavelength of the light source 1 can be maintained at the preset use wavelength.

According to this embodiment, as in the second embodiment, the wavelength management module can be further miniaturized and mass-produced, as compared with the conventional configuration in which the optical branching is performed in the space.
In addition to the effect that integration and multi-functionality can be achieved advantageously, in particular, since a bandpass filter is used as the wavelength selection means, it is suitable for wavelength management for a single wavelength, and the accuracy of wavelength control is high. Is good.

FIG. 7 is a schematic configuration diagram showing a sixth embodiment of the wavelength management device of the present invention. Reference numeral 610 in the figure indicates a wavelength management module. 7, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The wavelength management module 610 of the present embodiment is largely different from the wavelength management module 110 of the first embodiment in that a bandpass filter 614 is provided on the waveguide type optical branching means 111, and the waveguide type optical branching unit 610 is provided. Branching means 111
The point is that the collimator lens 112 and the optical resonator 14 are not provided outside.

Bandpass filter 6 in this embodiment
As 14, a dielectric multilayer filter having a transmission characteristic as shown in FIG. 6, for example, is used similarly to the bandpass filter 414 in the fourth embodiment. In the present embodiment, the bandpass filter 614 is provided on the waveguide type optical branching means 111. That is, the first branch signal light M is provided on the upper surface of the waveguide type optical branching means 111.
A groove having a depth reaching the core layer is formed at a position where the optical waveguide 111a for propagating 1 is formed, and the bandpass filter 614 is inserted in the groove. Further, in order to prevent reflection on the incident surface of the bandpass filter 614, the bandpass filter is set so that the angle formed by the incident surface of the bandpass filter 614 and the optical axis of the optical waveguide 111a is 90 ° ± 2 to 5 °. It is preferable to determine the position of the filter 614.

In the present embodiment, the signal light incident on the waveguide type optical branching means 111 is branched into the main signal light S and the monitor signal light M, and the monitor signal light M is further divided into
It is branched into a first branch signal light M1 and a second branch signal light M2. Since the bandpass filter 614 is provided in the middle of the optical waveguide through which the first branched signal light M1 is propagated, the first branched signal light M1 is generated by this bandpass filter 6
It is incident on 14.

The transmitted light transmitted through the bandpass filter 614 is emitted from the waveguide type optical branching means 111, and the light intensity thereof is measured by the first photodiode 15. On the other hand, the second branched signal light M2 is emitted from the waveguide type optical branching means 111, and its light intensity is measured by the second photodiode. In order to improve the efficiency of incidence on the first photodiode 15 and the second photodiode 17, a gap between the emission end of the waveguide type optical branching unit 111 and the first photodiode 15 may be added as necessary. And / or waveguide type optical branching means 1
A condensing unit such as a condensing lens may be provided between the emission end of 11 and the second photodiode 17.

Then, as in the first and fourth embodiments, the arithmetic unit 5 measures the value of the light intensity measured by the first photodiode 15 and the second photodiode 17. The calculation processing is performed so as to obtain the difference between the light intensity value and the temperature of the LD light source 1 controlled by the control device 6 so that the light intensity difference always becomes a predetermined value α (preferably approximately zero). The oscillation wavelength of the light source 1 can be maintained at a preset use wavelength by controlling the controller or the LD introduction current. According to this embodiment, the same effect as that of the fourth embodiment can be obtained, and in particular, since the bandpass filter 614 is provided on the waveguide type optical branching means 111, further miniaturization can be achieved. It is possible.
In the fifth embodiment as well, a bandpass filter can be similarly provided on the waveguide type optical branching means 111.

FIG. 8 shows a seventh embodiment of the wavelength control device of the present invention. (A) is a schematic configuration diagram of the device,
(B) is a front view of the block body 722. Reference numeral 7 in the figure
Reference numeral 10 indicates a wavelength management module. 8, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The wavelength management module 710 of the present embodiment is largely different from the wavelength management module 110 of the first embodiment in that a short period fiber grating 714 is used in place of the optical resonator 14 as the wavelength selection means, The collimator lens 112 is not provided, and instead of this, the first optical fiber 715 is provided,
Also, a second optical fiber 716 having a ferrule 717 is disposed between the waveguide type optical branching means 111 and the second photodiode 17.

In this embodiment, the waveguide type optical branching means 1 is used.
From the emission end face of 11, three lights of the main signal light S, the first branch signal light M1, and the second branch signal light M2 are emitted. The main signal light S is incident on the optical fiber 121 and
The branched signal light M1 is incident on the first optical fiber 715, and the second branched signal light M2 is incident on the second optical fiber 716. These three optical fibers 121, 715, 716 and the waveguide type optical branching means 11
In the connection part with 1, the three optical fibers 121, 71
As shown in FIG. 8B, the end portions of the optical fibers 121, 715, 716 and the end portions of the optical fibers 121, 715, 716 and the end portions of the optical fibers 121, 715 and 716 are in the block body 722.
The two end faces are held together so that they are flush with each other. Then, these three optical fibers 121, 715, 7
16 and the end faces of the block body 722 are adhered to the emission end face of the waveguide type optical branching means 111 by using an ultraviolet curable adhesive. In the present embodiment, the block body 722 provided on the emission end side of the waveguide type optical branching unit 111 is
As shown in FIG. 8B, a plate-shaped upper block 724 made of glass is laminated on a rectangular parallelepiped lower block 723 made of glass or ZrO ₂ , and three Vs are provided on the upper surface of the lower block 723. The grooves 725 are formed in parallel. The ends of the optical fibers 121, 715, 716 are V
It is held so as to be sandwiched between the inner surface of the groove 725 and the lower surface of the upper block 724.

The first optical fiber 715 is connected to the short period fiber grating 714. The short-period fiber grating 714 is obtained by periodically changing the refractive index of the optical fiber core in a short period of 1 μm or less. For example, like the short-period fiber grating 24 in the conventional example, as shown in FIG. Simple V-shaped transmittance-
Those having wavelength characteristics are used. The first optical fiber 715 is an optical fiber separate from the short-period fiber grating 714 and is a short-period fiber grating 714.
Alternatively, the extra length portion of the short period fiber grating 714 may be used as the first optical fiber 715 for connection with the waveguide type optical branching means 111. In the present embodiment, the short period fiber grating 714
Is fixed to the ceramic package 718. The first branched signal light M1 emitted from the waveguide type optical branching means 111 is incident on the short-period fiber grating 714 via the first optical fiber 715, transmitted through the short-period fiber grating 714, and emitted. The intensity of the transmitted light is measured by the first photodiode 15.

On the other hand, the end on the emission side of the second optical fiber 716 is fixed in the ferrule 717. Second branched signal light M2 emitted from the waveguide type optical branching means 111
Is emitted through the second optical fiber 716, and its light intensity is measured by the second photodiode 17. The first
In order to improve the efficiency of incidence of the light on the photodiode 15 and the second photodiode 17, the distance between the emission end of the short-period fiber grating 714 and the first photodiode 15 and / or the second photodiode 15 is increased as necessary. A condensing unit such as a condensing lens may be provided between the emission end of the optical fiber 716 and the second photodiode 17. In the present embodiment, among the components of the wavelength management module 710, at least the waveguide type optical branching means 111, the short period fiber grating 714, the ferrule 717, and the first photodiode 1 are included.
Although not shown, the fifth photodiode 17 and the second photodiode 17 are fixed to a board or a housing that collectively houses them.

Then, as in the first embodiment, the arithmetic unit 5 calculates the light intensity value measured by the first photodiode 15 and the light intensity value measured by the second photodiode 17. Is calculated so that the difference between the light intensities is always a predetermined value α (preferably approximately zero), the controller 6 controls the temperature controller of the LD light source 1 or the LD introduction current. By controlling, the oscillation wavelength of the light source 1 can be maintained at the preset use wavelength.

According to the present embodiment, the signal light emitted from the light source 1 is converted into the main signal light S, the first branch signal light M1 and the second branch signal light M1.
Since the optical branching into the three branching signal lights M2 is performed on one waveguide type optical branching means 111, the optical branching is performed as compared with the conventional optical fiber coupler. The wavelength management module 7 requires only a small distance.
10 can be miniaturized. Further, the waveguide type optical branching means 111 and the respective optical fibers 120, 121, 715,
In order to optically connect with 716, since the block bodies 122 and 722 provided with V-grooves are used to bond and fix with an adhesive, the work is simpler than the fusion-splicing method and necessary for connection. The extra length of the optical fiber can be small. In addition, three V-grooves 7 are connected to the connection on the output end side of the waveguide type optical branching means 111.
By using a block body 722 with 25
Since the optical fibers 121, 715, and 716 of the book can be collectively connected to each of the three emission ends of the waveguide type optical branching means 111 with good reproducibility, workability is good and mass production can be achieved. preferable. For example, in FIG.
In the conventional configuration shown in FIG. 1, a part including the first coupler 2, the second coupler 21, the short-period fiber grating 24, the first photo diode 25, and the second photo diode 26 among the components of the wavelength control device. The size of the housing required to accommodate the light source is, for example, 10 mm in length, 180 mm in width, 8 mm in height and 14400 mm ³ in volume, whereas according to the configuration of this embodiment, the wavelength management module 7
It is possible to reduce the size of the housing that houses 10 to, for example, 10 mm in length, 40 mm in width, 8 mm in height and 3200 mm ³ in volume.

Furthermore, in recent years, various optical modules are being integrated and multifunctional using a planar optical waveguide, but in the present embodiment, a waveguide type optical branching means is used. The wavelength management module can be integrated and have multiple functions. Further, since the short-period fiber grating 714 is held by the ceramic package 718, the wavelength characteristics are good and the optical characteristics are stable. Furthermore, according to the configuration using the short-period fiber grating as the wavelength selecting means as in the present embodiment, the wavelength setting accuracy is high and the cost can be reduced.

FIG. 9 is a schematic configuration diagram showing an eighth embodiment of the wavelength management device of the present invention. Reference numeral 810 in the figure denotes a wavelength management module. 1 and 8 in FIG.
The same components as those of the above are given the same reference numerals and the description thereof will be omitted. The wavelength management module 810 of the present embodiment is largely different from the wavelength management module 710 of the seventh embodiment in that the monitoring signal light M is emitted without being split into a second optical fiber 716, That is, the second photodiode 17 and the arithmetic unit 5 are not provided.

In this embodiment, an optical waveguide 811a having one branch is formed in the waveguide type optical branching means 811 as shown in FIG. 9, and the main signal light S and the monitor signal light M are separated from each other. The light intensity ratio is S: M = 95: 5. Two lights, a main signal light S and a monitor signal light M, are emitted from the emission end face of the waveguide type optical branching unit 811. The main signal light S is incident on the optical fiber 121, and the monitoring signal light M is the first optical fiber 715.
Is incident on.

Two optical fibers 121 and 715 on the output side
At the connecting portion between the optical fiber branching means 811 and the waveguide type optical branching means 811, the end portions of the two optical fibers 121 and 715 have two V insides.
In the block body 822 having the groove, the optical fibers 121,
The end surface of 715 and the end surface of the block body 822 are held together so that they are flush with each other. Then, the end faces of the two optical fibers 121 and 715 and the block body 822 are waveguide type optical branching means 8 using an ultraviolet curing adhesive.
It is adhered to the emission end face of 11. The block body 822 according to the present embodiment has substantially the same configuration as the block body 722 according to the seventh embodiment, and the V groove 72 is provided.
Only the number of 5 is different.

The monitor signal light M emitted from the waveguide type optical branching means 811 is incident on the short period fiber grating 714 via the first optical fiber 715, transmitted through the short period fiber grating 714 and emitted. The intensity of the transmitted light is measured by the first photodiode 15. In order to improve the efficiency of incidence on the first photodiode 15, a condenser means such as a condenser lens is provided between the emission end of the short-period fiber grating 714 and the first photodiode 15 as necessary. May be provided. In the present embodiment, as in the second embodiment, the control device 6 controls the light source so that the value of the transmitted light intensity measured by the first photodiode 15 becomes a preset value β. By controlling the oscillation wavelength of the light source 1, the oscillation wavelength of the light source 1 can be maintained at the preset use wavelength.

According to the present embodiment, as in the seventh embodiment, the monitoring signal light M is used for measurement (first branch signal light M1) and reference (second branch signal light M2). Although the accuracy is slightly inferior to the configuration in which the light intensity is different between the two split light beams, the wavelength of the light source can be controlled with a simple device configuration and the number of parts is small. A wavelength management device can be provided at low cost.
Further, in the present embodiment, as in the case of the seventh embodiment, the wavelength management module can be downsized, mass-produced, integrated, and multifunctional as compared with a configuration in which optical branching is performed using a conventional optical fiber coupler. In addition to the effect that it can be achieved advantageously,
Since the signal light emitted from the light source 1 is branched once,
The waveguide type optical branching unit 811 for performing the optical branching can be made smaller than that in the seventh embodiment, and the wavelength management module 810 can be further downsized.

FIG. 10 is a schematic configuration diagram showing a ninth embodiment of the wavelength management device of the present invention. Reference numeral 910 in the figure denotes a wavelength management module. In FIG. 10, the same components as those in FIGS. 1 and 8 are designated by the same reference numerals, and the description thereof will be omitted. The wavelength management module 910 of the present embodiment is
The wavelength management module 710 in the seventh embodiment.
The major difference is that the short-period fiber grating 9
The point is that the reflected light of 14 is received by the first photodiode 15.

In this embodiment, the first branch signal light M1 in the waveguide type optical branching means 111 has a first end at the exit end thereof.
Optical fiber 915 is connected, and the first optical fiber 915 is connected to the short-period fiber grating 914. The short period fiber grating 914
It is sufficient that the refractive index of the optical fiber core is periodically changed in a short period of 1 μm or less, and the reflected light has wavelength dependence. For example, similar to the short-period fiber grating 24 in the conventional example, one having a reflectance-wavelength characteristic as shown in FIG. 19A is used. Further, the first optical fiber 915 is provided with a branch fiber 915a, and the reflected light of the short-period fiber grating 914 is incident on the first photodiode via the branch fiber 915a, and its light intensity is measured. Is configured. In this embodiment, the short-period fiber grating 914 is fixed inside the ceramic package 918. The transmitted light of the short-period fiber grating 914 is terminated at the output end of the short-period fiber grating 914 so that adverse effects such as end face reflection do not occur. In the present embodiment, it is preferable to prepare a first optical fiber 915 having a branch fiber 915a separately from the short-period fiber grating 914, and connect this to the short-period fiber grating 914 for use.

On the other hand, the second branched signal light M2 emitted from the waveguide type optical branching means 111 is the second optical fiber 71.
It is incident on the second photodiode 17 via 6 and its light intensity is measured. In addition, in order to improve the efficiency of incidence on the first photo diode 15 and the second photo diode 17, if necessary, between the emission end of the branch fiber 915a and the first photo diode 15, and / or the first photo diode 15. A condensing unit such as a condensing lens may be provided between the emission end of the second optical fiber 716 and the second photodiode 17.

Then, as in the first embodiment, the arithmetic unit 5 calculates the light intensity value measured by the first photodiode 15 and the light intensity value measured by the second photodiode 17. And a control device 6 controls the temperature controller of the LD light source 1 or the LD introduction current so that the difference between the light intensities is always a predetermined value α (preferably approximately zero). By doing so, the oscillation wavelength of the light source 1 can be maintained at the preset use wavelength. According to the present embodiment, similar to the seventh embodiment, the conventional
Compared with the configuration that performs optical branching using an optical fiber coupler,
In addition to the effect that the wavelength management module can be advantageously miniaturized, mass-produced, integrated, and multifunctional, in particular, the reflected light of the short-period fiber grating 914 is measured by the first photodiode 15, Since it is used to detect wavelength fluctuations, wavelength setting accuracy is high and cost reduction is possible.

FIG. 11 shows a tenth embodiment of the wavelength control device of the present invention.
2 is a schematic configuration diagram showing an embodiment of FIG. Reference numeral 101 in the figure
Reference numeral 0 indicates a wavelength management module. 11, the same components as those in FIG. 8 are designated by the same reference numerals, and the description thereof will be omitted. The wavelength management module 1010 of this embodiment is substantially different from the wavelength management module 710 of the seventh embodiment in that the short-period fiber grating 714 is used.
Instead of this, a short-period grating 1014 is formed on the optical waveguide 111a. Further, in the present embodiment, the first photodiode 15 is optically connected to the emission end of the first branch signal light M1 in the waveguide type optical branching means 111, and the second photodiode 17 It is optically connected to the emission end of the second branched signal light M2 in the waveguide type optical branching means 111. In order to improve the efficiency of incidence on the first photo diode 15 and the second photo diode 17, the exit end of the waveguide type optical branching unit 111 and the first photo diode 15 and / Alternatively, a condensing unit such as a condensing lens may be provided between the second photo diode 17 and the second photo diode 17.

In the present embodiment, the signal light incident on the waveguide type optical branching means 111 is branched into the main signal light S and the monitor signal light M, and the monitor signal light M is further divided into
It is branched into a first branch signal light M1 and a second branch signal light M2. Of the first branched signal light M1, the transmitted light that has passed through the short period grating 1014 is the first photodiode 15 provided at the emission end of the waveguide type optical branching means 111.
The light intensity is measured and the light intensity is measured. On the other hand, the second branched signal light M2 is incident on the second photodiode 17 provided at the emission end of the waveguide type optical branching means 111, and the light intensity thereof is measured. Then, similar to the seventh embodiment, the difference between the value of the light intensity measured by the first photodiode 15 and the value of the light intensity measured by the second photodiode 17 is calculated by the arithmetic unit 5. The control device 6 controls the temperature controller of the LD light source 1 or the LD introduction current so that the difference between the light intensities always becomes a predetermined value α (preferably approximately zero). Thus, the oscillation wavelength of the light source 1 can be maintained at the preset use wavelength.

According to this embodiment, the same effect as that of the seventh embodiment can be obtained, and in particular, since the short period grating 1014 is provided on the waveguide type optical branching means 111, further miniaturization is achieved. It is possible to

FIG. 12 shows an eleventh embodiment of the wavelength control device of the present invention.
2 is a schematic configuration diagram showing an embodiment of FIG. Reference numeral 111 in the figure
Reference numeral 0 indicates a wavelength management module. 12, the same components as those of FIG. 9 are designated by the same reference numerals and the description thereof will be omitted. The wavelength management module 1110 of the present embodiment is largely different from the wavelength management module 810 of the eighth embodiment in that the short-period fiber grating 714 is used.
Instead of this, a short period grating 1114 is formed on the optical waveguide 111a. Further, in the present embodiment, the first photodiode 15 is optically connected to the emission end of the monitor signal light M in the waveguide type optical branching unit 811. In order to improve the efficiency of incidence on the first photodiode 15, if necessary, a condenser lens or the like may be provided between the emission end of the waveguide type optical branching unit 811 and the first photodiode 15. Means may be provided.

In this embodiment, the signal light incident on the waveguide type optical branching means 811 is split into the main signal light S and the monitor signal light M. Of the monitor signal light M,
The transmitted light that has passed through the short-period grating 1114 is incident on the first photodiode 15 provided at the emission end of the waveguide type optical branching unit 811, and the light intensity thereof is measured.
Then, as in the case of the eighth embodiment, the controller 6 oscillates the light source 1 so that the value of the transmitted light intensity measured by the first photodiode 15 becomes a preset value β. By controlling the wavelength, the oscillation wavelength of the light source 1 can be maintained at the preset use wavelength.

According to the present embodiment, the same effect as that of the eighth embodiment can be obtained, and in particular, since the short period grating 1114 is provided on the waveguide type optical branching means 811, further miniaturization is achieved. It is possible to

FIG. 13 shows a twelfth embodiment of the wavelength control device of the present invention.
2 is a schematic configuration diagram showing an embodiment of FIG. Reference numeral 121 in the figure
Reference numeral 0 indicates a wavelength management device. 13, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The wavelength management module 1210 of this embodiment is largely different from the wavelength management module 110 of the first embodiment in that the optical path connecting the light source 1 and the incident end of the waveguide type optical branching means 111 is a polarization maintaining optical fiber. The polarization-maintaining optical fiber 121p is connected to the emission end of the main signal light S in the waveguide type optical branching means 111.

In the present embodiment, the waveguide type optical branching means 111 splits the light source light incident through the polarization maintaining optical fiber 120p on the incident side into the main signal light S and the monitor signal light M. Further, it has a function of branching the monitor signal light M into a first branch signal light M1 and a second branch signal light M2, which is similar to the waveguide type optical branching means 111 in the first embodiment. Any thing can be used. In this embodiment, since the light source light is incident on the waveguide type optical branching means 111 in a state where the polarization plane is preserved, the waveguide type optical branching means 111 is also configured to preserve the polarization plane. The waveguide type optical branching means is more optically stable than the optical branching means composed of optical fibers, and the polarization plane of outgoing / propagating light is almost maintained even if the structure for preserving the polarization plane is not provided. To be done. Further, there is an advantage that the plane of polarization is substantially preserved even after branching, and the PDL (polarization dependent loss) caused by branching is also minute. However, when the optical path in the waveguide type optical branching means 111 becomes long, the fluctuation of the plane of polarization becomes large and the influence is exerted. Therefore, the length of the waveguide type optical branching means 111 in the longitudinal direction may be 30 mm or less. It is preferably 20 mm or less.

In this embodiment, the polarizer 19 is provided between the incident end of the waveguide type optical branching means 111 and the connection end of the polarization maintaining optical fiber 120p, and the polarization maintaining optical fiber 120 is provided.
It is preferable that the light source light propagating in p is incident on the waveguide type optical branching means 111 via the polarizer 19. Specifically, the polarization maintaining optical fiber 1 is internally provided.
Using a block body 122a having a V groove into which 20p is inserted and a groove into which the polarizer 19 is inserted, the connection end of the polarization maintaining optical fiber 120a and the polarizer 19 are contacted in this block body 122a. The end faces of the block body 122a are brought into contact with each other and the waveguide type optical branching means 11 is formed by using an ultraviolet curable adhesive.
It is preferable to bond it to the end face of No. 1. The polarizer 19 is
It is possible to adopt a configuration in which this is not provided, but if the light source light is transmitted through the polarizer 19 before being made incident on the waveguide type optical branching means 111, the waveguide type optical branching means 111 has one polarization. It is preferable that only the incident light is incident and the extinction ratio of the main signal light S in the waveguide type optical branching means 111 is improved. The extinction ratio of the main signal light S in the waveguide type optical branching means 111 is 25d.
It is preferably B or more.

On the other hand, at the emission end of the main signal light S in the waveguide type optical branching means 111, the polarization maintaining optical fiber 121p is provided in the V groove in the block body 122, and its connection end face and the end face of the block body 122. And the end faces of the polarization-maintaining optical fiber 121p and the block body 122 are adhered to the end face of the waveguide type optical branching means 111 by an ultraviolet curable adhesive. In this embodiment, the polarization-maintaining optical fiber 1 on the incident side is
20p and the polarization-maintaining optical fiber 121p on the output side are connected to the waveguide type optical branching means 111, the direction of the polarization plane in the polarization-maintaining optical fiber 120p on the input side and the polarization-maintaining optical fiber 121p on the output side. It is necessary to make adjustments so that the directions of the polarization planes match. In the present embodiment, the first branched signal light M1 and the second branched signal light M2 propagate in a state in which the polarization planes are preserved, but the optical resonator, the first photodiode 15, and the second Since the photodiode 17 has almost no wavelength dependence,
Wavelength management can be performed in the same manner as in the first embodiment.

According to this embodiment, the signal light emitted from the light source 1 is incident on the waveguide type optical branching means 111 via the polarization maintaining optical fiber 120p, and is guided to the waveguide type optical branching means 1.
In 11, the wave is propagated while maintaining the polarization plane. Since the polarization maintaining optical fiber 121p is connected to the emission end of the main signal light S branched on the waveguide type optical branching means 111, the main signal light emitted from the waveguide type optical branching means 111. S is further propagated in a state where the polarization plane is maintained. As described above, in the present embodiment, the main signal light S in which the plane of polarization is preserved can be obtained, and therefore, it can be suitably used for wavelength management of a system including a device having polarization dependency such as the LN modulator 20. You can Further, the waveguide type optical branching means 111 does not need to be newly provided with a structure for preserving the plane of polarization, and the ordinary waveguide mode optical branching means 111 for single mode can be used as it is, so that it is easy to obtain. And the price can be kept low. Therefore, the price of the wavelength management device can be significantly reduced as compared with the conventional configuration in which the polarization maintaining coupler is used for branching the main signal light and the monitor signal light.

Further, in this embodiment, the optical branching into the main signal light S, the first branch signal light M1 and the second branch signal light M2 is performed on one waveguide type optical branching means 111. Therefore, the space required for optical branching is smaller than that of the conventional configuration, and the wavelength management module 1210 is downsized.

Besides this, also in the present embodiment, as in the case of the first embodiment, it is possible to apply the already established mass production technique to the production of the waveguide type optical branching means 111, and the wavelength. Since it is relatively easy to arrange each component in the management module, mass production is possible and cost can be reduced. In the future, the wavelength management module can be integrated and have multiple functions. And the like.

FIG. 14 shows a thirteenth wavelength management device of the present invention.
2 is a schematic configuration diagram showing an embodiment of FIG. Reference numeral 131 in the figure
Reference numeral 0 indicates a wavelength management device. 14, the same components as those in FIG. 8 are designated by the same reference numerals and the description thereof will be omitted. The wavelength management module 1310 of this embodiment is the twelfth embodiment.
Similar to the above embodiment, the light source light is configured to propagate with the polarization plane being held. Specifically, the wavelength management module 1310 of this embodiment is different from the wavelength management module 710 of the seventh embodiment in that
Similar to the second embodiment, the optical path connecting the light source 1 and the incident end of the waveguide type optical branching means 111 is the polarization maintaining optical fiber 1.
20 p, a waveguide type optical branching means 111
The polarization maintaining optical fiber 121p is provided at the exit end of the main signal light S in the waveguide type optical branching means 111, in that the polarizer 19 is provided between the incident end of the optical path and the connection end of the polarization maintaining optical fiber 120p. It is the point of connection. In the present embodiment, the first branched signal light M1 and the second branched signal light M2 are propagated with the polarization planes preserved, but the short-period fiber grating 714 and the first photodiode 1 are used.
Since the fifth and second photodiodes 17 do not have wavelength dependence, wavelength management can be performed in the same manner as in the first embodiment.

According to this embodiment, the same effect as that of the twelfth embodiment can be obtained, and the remaining main signal light S obtained by branching the monitor signal light M from the light source light is preserved in the plane of polarization. Since the light can be propagated in a closed state, it can be suitably used for wavelength management of a system including a device having polarization dependence such as the LN modulator 20.
Further, particularly in the present embodiment, since the short-period fiber grating is used as the wavelength selecting means, the wavelength setting accuracy is high and the cost can be significantly reduced.

In the second to sixth embodiments and the eighth to eleventh embodiments, the light source 1 and the incident end of the waveguide type optical branching means 111 are arranged in the same manner as the twelfth embodiment. The optical path to be connected is composed of the polarization maintaining optical fiber 120p,
A polarization-maintaining optical fiber 121p is connected to the output end of the main signal light in the waveguide type optical branching unit 111, and preferably the input end of the waveguide type optical branching unit 111 and the polarization maintaining optical fiber 1 are connected.
By providing the polarizer 19 with the connection end of 20p, a wavelength management module and a wavelength management device in which the light source light is propagated in a state in which the polarization plane is held can be obtained. Further, in the fourth to sixth embodiments, the bandpass filter is used as the wavelength selecting means, but the bandpass filter 414,
Since 614 also has no wavelength dependence, wavelength management can be performed in the same manner even in these embodiments, even if the light source light is propagated in a state in which the polarization plane is held.

[0080]

As described above, according to the present invention,
In the wavelength management module, the function of branching the signal light emitted from the light source into the main signal light and the monitor signal, and the function of branching the monitor signal light into the first branch signal light and the second branch signal light By using a waveguide-type optical branching means having, a conventional configuration for performing optical branching in space,
Alternatively, the space required for optical branching may be smaller than that of a configuration in which optical branching is performed using an optical fiber coupler, and the wavelength management module can be downsized. Further, it is possible to easily combine the waveguide type optical branching means with other parts to form a hybrid. In addition, the mass production technology that has already been established can be applied to the production of the waveguide type optical branching means, and the mass production of the wavelength management module and the cost reduction can be achieved. Furthermore, in recent years, various optical modules have been integrated and multifunctional using a planar optical waveguide, but since the present invention uses a waveguide type optical branching means, it is possible to use the optical waveguide in the future in a wavelength management module. It can also be integrated and multifunctional.

Furthermore, the signal light oscillated from the light source is incident on the waveguide type optical branching means via the polarization maintaining optical fiber and is polarized to the exit end of the main signal light in the waveguide type optical branching means. By connecting the wave-holding optical fiber, the main signal light can be propagated in a state where the polarization plane is preserved, so that the cost of wavelength management in a system including a device having polarization dependence can be reduced, and The size of the wavelength management device can be reduced.

[Brief description of drawings]

1A and 1B show a first embodiment according to the present invention, FIG. 1A is a schematic configuration diagram of an apparatus, and FIG. 1B is a front view showing an example of a block body used for optical connection.

FIG. 2 is a schematic configuration diagram showing a second embodiment according to the present invention.

FIG. 3 is a graph for explaining a wavelength management method according to a second embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing a third embodiment according to the present invention.

FIG. 5 is a graph showing an example of transmission characteristics of an optical resonator used in a third embodiment according to the present invention.

FIG. 6 is a graph showing an example of transmission characteristics of the bandpass filter according to the present invention.

FIG. 7 is a schematic configuration diagram showing a sixth embodiment according to the present invention.

FIG. 8 shows a seventh embodiment according to the present invention, (a) is a schematic configuration diagram of the device, and (b) is a front view showing an example of a block body used for optical connection.

FIG. 9 is a schematic configuration diagram showing an eighth embodiment according to the present invention.

FIG. 10 is a schematic configuration diagram showing a ninth embodiment according to the present invention.

FIG. 11 is a schematic configuration diagram showing a tenth embodiment according to the invention.

FIG. 12 is a schematic configuration diagram showing an eleventh embodiment according to the invention.

FIG. 13 is a schematic configuration diagram showing a tenth embodiment according to the invention.

FIG. 14 is a schematic configuration diagram showing an eleventh embodiment according to the invention.

FIG. 15 is a schematic configuration diagram showing an example of a conventional wavelength management device.

FIG. 16 is a schematic configuration diagram showing an example of an optical resonator.

FIG. 17 is a graph showing an example of transmission characteristics of an optical resonator.

FIG. 18 is a schematic configuration diagram showing an example of a conventional wavelength management device.

FIG. 19 shows the transmission characteristics of a short-period fiber grating, where (a) shows the wavelength dependence of reflectance,
(B) shows the wavelength dependence of the transmittance.

FIG. 20 is a schematic configuration diagram showing an example of a conventional wavelength management device.

FIG. 21 is a schematic configuration diagram showing an example of a conventional wavelength management device.

[Explanation of symbols]

1 ... LD light source, 2a, 2b, 2c, 120p, 121p
... polarization maintaining optical fiber, 5 ... computing means, 6 ... control means,
11, 110, 210, 310, 610, 710, 81
0,910,1010,1110,1210,1310
... Wavelength management module, 14, 314 ... Optical resonator (wavelength selection means), 15 ... First photodiode (measurement means),
Reference numeral 17 ... Second photodiode (measuring means), 19 ... Polarizer, 24, 714, 914 ... Short-period fiber grating (wavelength selecting means) 111, 211, 811 ... Waveguide type optical branching means, 112, 312 ... Collimate Lens (collimator), 414, 614 ... Band pass filter (wavelength selection means) 715, 915 ... First optical fiber, 71
6 ... 2nd optical fiber, 1014, 1114 ... Short period grating (wavelength selection means), S ... Main signal light, M ... Monitor signal light, M1 ... 1st branch signal light, M2 ... 2nd
Branch signal light.

Continuation of front page (51) Int.Cl. ⁷ Identification code FI Theme Coat (reference) H04J 14/02 (72) Inventor Hitoshi Oguri 28 6th, 6th Town, Chiyoda-ku, Tokyo Sumitomo Osaka Cement Co., Ltd. (72) Inventor Junichiro Ichikawa 6-6, Rokubancho, Chiyoda-ku, Tokyo 28 Sumitomo Osaka Cement Co., Ltd. (72) Inventor Takeshi Sakai 28-6, Rokubancho, Chiyoda-ku, Tokyo (72) Inventor Masayuki Ichioka 28, 6 Sumitomo Osaka Cement Co., Ltd., Chiyoda-ku, Tokyo (72) Inventor Yuki Kanehara 6-6, 6 Bancho, Chiyoda-ku, Tokyo 28 Inventor, Sumitomo Osaka Cement Co., Ltd. Kenichi Kuboji Chiyoda-ku, Tokyo 6th, Rokubancho 28 F-term in Sumitomo Osaka Cement Co., Ltd. (reference) 2H047 KA03 KA12 LA12 RA08 TA11 5F073 EA03 FA05 GA12 GA13 5K002 BA04 CA08 CA12 DA02 EA05

Claims (11)

[Claims] 1. A wavelength management module for controlling the oscillation wavelength of a light source so as to keep it at a preset use wavelength, wherein the signal light emitted from the light source is split into a main signal light and a monitor signal light. A waveguide type optical branching unit having a function of branching the monitoring signal light into a first branch signal light and a second branch signal light; and an optical path of the first branch signal light and the first branch signal light. Wavelength selection means having a wavelength dependency of transmittance, which is provided on at least one of the optical paths of the two branched signal lights; and a first measuring means provided on the optical path of the first branched signal light, A second measuring means provided on the optical path of the second branched signal light, wherein the measuring means on the optical path provided with the wavelength selecting means is the reflected light of the wavelength selecting means or The transmitted light is received and the light intensity is measured. The measuring means of the optical path which is-option means not provided, the wavelength management module, characterized by measuring the light intensity by receiving the branch signal light emitted from the waveguide type optical branching device. 2. A wavelength management module for controlling the oscillation wavelength of a light source so as to keep it at a preset use wavelength, wherein the signal light emitted from the light source is split into a main signal light and a monitor signal light. A waveguide type optical branching means having a function, a wavelength selecting means into which the signal light for monitoring has a transmittance having wavelength dependency, and a reflected light or a transmitted light of the wavelength selecting means for receiving the A wavelength management module comprising: a third measuring means for measuring light intensity. 3. The wavelength selecting means comprises two substrates, one surface of which is a reflecting surface having a predetermined reflectance, arranged substantially in parallel so that the reflecting surfaces face each other with a medium interposed therebetween. The wavelength management module according to claim 1, which is a bandpass filter using an optical resonator or a dielectric multilayer film. 4. The wavelength management module according to claim 3, wherein a collimator is provided as an incident means to the wavelength selecting means. 5. The wavelength management module according to claim 1, wherein the wavelength selecting means is provided on the waveguide type optical branching means. 6. The wavelength selecting means comprises a short-period fiber grating, and the light emitted from the waveguide type optical branching means is incident on the short-period fiber grating via an optical fiber. Item 3. The wavelength management module according to item 1 or 2. 7. The wavelength management module according to claim 1, wherein the wavelength selecting means is a short period grating formed on the waveguide type optical branching means. 8. A signal light oscillated from said light source is incident on said waveguide type optical branching means via a polarization maintaining optical fiber, and at the exit end of said main signal light in said waveguide type optical branching means. The wavelength management module according to claim 1, wherein a polarization maintaining optical fiber is connected. 9. The wavelength management module according to claim 8, wherein a polarizer is provided on the optical path before the signal light emitted from the light source is incident on the waveguide type optical branching means. . 10. A wavelength management module according to any one of claims 1, 3, 4, 5, 6, 7, 8 or 9, wherein the first measuring means and the second measuring means are provided. And a calculating means for obtaining a difference between the light intensity measured by the first measuring means and the light intensity measured by the second measuring means, so that the difference between the light intensities has a predetermined value. A wavelength management device comprising control means for controlling the oscillation wavelength of the light source. 11. A wavelength management module according to any one of claims 2, 3, 4, 5, 6, 7, 8 or 9, wherein the third measurement means is provided, and the third wavelength management module. A wavelength management device comprising control means for controlling the oscillation wavelength of the light source so that the light intensity measured by the measurement means has a predetermined value.