JP2002243546A - Wavelength control module using optical resonator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize a transmission characteristic of an optical resonator constituting a wavelength control module. SOLUTION: This wavelength control module is equipped with the optical resonator formed by arranging two substrates having each one surface functioning as a reflecting surface having a prescribed reflectance so that the reflecting surfaces are faced each other in parallel across a medium, and by interposing a spacer between the two substrates, a means for allowing a monitoring light signal to enter the optical resonator as parallel light, and a means for detecting the change of the intensity of transmitted light from the optical resonator. In the module, an optical path from the incident means to the detection means after transmission through the optical resonator is stored in a casing, and the optical resonator is fixed on the inner surface of the casing. The module is characterized by installing a fixing member 41 for suppressing movement of the optical resonator 114 on the inner surface of the casing.

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 using an optical resonator, and more particularly to an optical resonator having improved transmission characteristic stability.

[0002]

2. Description of the Related Art In a wavelength division multiplexing system (hereinafter referred to as WDM system), optical signals of a plurality of wavelengths are used. The wavelength interval becomes shorter. WDM
In general, a semiconductor laser (L
D) is used, but in the LD, the center wavelength of the emitted light fluctuates due to a change over time or the environment, and this may cause crosstalk with an adjacent wavelength to cause interference. In order to keep the oscillation wavelength of the LD constant, for example, FIG.
A wavelength management system using a wavelength management module as shown in FIG.

In this figure, reference numeral 1 denotes an LD light source, 11
Indicates a wavelength management module. The LD light source 1 is configured so that the oscillation wavelength can be controlled by controlling the chip temperature or the LD introduction current. In the former case, the LD light source 1 includes a temperature controller (not shown). 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 transmission optical fiber as signal light, and the remaining 5% is made incident on the wavelength management module 11 as a monitoring optical signal. In the wavelength management module 11, first, the collimator 12 converts the monitoring optical signal into parallel light and outputs the half mirror 1.
3 The transmitted light of the half mirror 13 is incident on the optical resonator 14, and the transmitted light intensity of the optical resonator 14 is measured by the first photodiode 15. On the other hand, the half mirror 13
Is guided to the second photodiode 17 via the reflection mirror 16 and its light intensity is measured. Generally, a collimator 12, a half mirror 13, an optical resonator 14, and a first photodiode 1 constituting a wavelength management module 11
5, the reflection mirror 16, the second photodiode 17, and the like are fixed to a board or a housing that accommodates them collectively.

FIG. 8 is a sectional view of an example of the optical resonator 14 as viewed from above. The optical resonator 14 of this example includes two reflective films 21a and 21b having a predetermined reflectance on one surface.
The substrates 21 and 21 ′ are arranged in parallel so that the reflection films 21a and 21b face each other with the medium 22 interposed therebetween.
A spacer 23 is arranged between the two substrates 21 and 21 'so that the length d (hereinafter sometimes referred to as a cavity length) between the substrates 21 and 21' is set to a predetermined length. In the example, the medium 22 is an air layer. . The light transmittance of the optical resonator 14 has wavelength dependency, and for example, has a wavelength-transmittance characteristic close to a sine wave as shown in FIG. Therefore, if the wavelength of the monitoring optical signal 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 monitoring optical signal changes. In this case, it appears as a change in the transmitted light intensity measured by the first photodiode 15.

Further, the intensity of the emitted light of the LD light source 1 may change with time. In this case, even if the wavelength of the emitted light is constant, the intensity of the transmitted light measured by the first photodiode 15 is reduced. Changes. Regarding this, since the value obtained by measuring the reflected light intensity of the half mirror 13 with the second photodiode changes in accordance with the change in the emitted light intensity of the LD light source 1, the light intensity measured with the first photodiode is changed. And the value of the light intensity measured by the second photodiode, an arithmetic operation is performed to calculate the difference between the transmitted light intensity measured by the first photodiode 15 and the outgoing light intensity. The amount of change in transmitted light intensity due to the change in intensity is canceled out, and the amount of change in transmitted light intensity due to a change in the wavelength of emitted light is found. Then, based on the amount of change in the transmitted light intensity after the arithmetic processing, the wavelength of the emitted light is returned to the original value, that is, the amount of change in the transmitted light intensity after the arithmetic processing is reduced to zero. It controls the temperature controller or the LD introduction current. In the figure, reference numeral 5 denotes an arithmetic unit, and 6 denotes a control unit.

However, in recent years, in order to cope with an increase in the wavelength interval in the WDM system, it has been required to reduce the fluctuation width of the oscillation wavelength of the LD light source 1. Therefore, in order to improve the accuracy of the wavelength management module, it has been desired to stabilize the transmission characteristics of the optical resonator 14 to a higher degree.

The present invention has been made in view of the above circumstances, and has as its object to stabilize the transmission characteristics of an optical resonator constituting a wavelength management module.

[0008]

As described above, for example, as shown in FIG. 8, two substrates 21 and 2 having reflection surfaces are provided.
1 ′ are arranged in parallel so that the reflection surfaces (reflection films 21a and 21b) face each other with the medium 22 interposed therebetween, and the two substrates 21 and
The optical resonator 14 having a spacer interposed between 1 ′ is
It has a transmission characteristic as shown in FIG. 9 and shows a peak of the transmittance at a constant wavelength interval. The transmittance T (λ) (unit:%) when the wavelength is λ (nm) is represented by the following equation (1). In the following formula (1), T ₀ is the maximum transmittance (peak value of the transmittance), n is the refractive index of the medium 22, d is the gap length, and θ is the incident angle with respect to the substrate 21. When the reflectances of the two reflecting surfaces (reflection films 21a and 21b) are R ₁ and R ₂ , respectively, F is represented by the following equation (2), and R in the equation (2) is represented by the following equation (3). ).

[0009]

(Equation 1)

The inventor of the present invention has determined that the optical resonator 14 has a difference in the linear expansion coefficient of each member of the housing, the adhesive, and the optical resonator.
Is displaced, which causes the optical resonator 14
We noticed that there may be fluctuations in the characteristics of. For example, when the optical resonator 14 moves in a rotation direction indicated by an arrow P in FIG. 10, a movement occurs such that a displacement occurs when the optical resonator 14 is viewed from above with the light incident direction being a horizontal direction. In this case, the incident angle θ with respect to the substrate 21 changes, and as can be seen from the above equation (1), even if the wavelength is constant, the transmittance of the optical resonator 14 fluctuates and a drift of the transmission wavelength occurs. Therefore, the present invention aims to stabilize the transmission characteristics of the optical resonator by suppressing such a change in the incident angle θ.

When the ambient temperature of the optical resonator 14 changes, the spacer 23 may be thermally expanded and the gap length d may change. According to equation (1), it is understood that the transmittance changes when the gap length d changes even when the wavelength is constant. Therefore, by suppressing such a change in the gap length d, the transmission characteristics of the optical resonator can be further stabilized.

In some cases, the refractive index n of the medium 22 changes due to a change in the ambient temperature of the optical resonator 14. For example, as the temperature increases, the volume of the medium 22 increases and the density decreases. As the density of the medium 22 decreases, the refractive index n decreases.
Then, as can be seen from Expression (1), when the refractive index n of the medium 22 changes, the transmittance changes, and the center wavelength drifts. Therefore, even if the ambient temperature changes, the medium 22
If the refractive index n is not changed, the transmission characteristics of the optical resonator can be further stabilized.

That is, in order to solve the above-mentioned problems, a wavelength management module according to the present invention comprises two substrates, one of which is a reflection surface having a predetermined reflectance, the reflection surfaces opposing each other across a medium. And an optical resonator having a spacer interposed between the two substrates, and means for causing a monitoring optical signal to be incident on the optical resonator as parallel light,
Means for detecting a change in intensity of transmitted light from the optical resonator, an optical path from the incident means to the optical resonator through the optical resonator to the detection means is housed in a housing, A wavelength management module in which the optical resonator is fixed on an inner surface of a housing, wherein a fixing member for suppressing movement of the optical resonator is provided on an inner surface of the housing. . Alternatively, a configuration in which a concave portion for suppressing the movement of the optical resonator may be provided on the inner surface of the housing. When the fixing member is provided, it is preferable that only one substrate among the constituent members of the optical resonator is bonded and fixed to the housing and / or the fixing member. An elastic member may be used as means for fixing the optical resonator to the housing and / or the fixing member. When the concave portion is provided, it is preferable that only one substrate among the constituent members of the optical resonator is bonded and fixed to the housing and / or the concave portion. An elastic member may be used as means for fixing the optical resonator to the housing and / or the recess.

In the present invention, the spacer is preferably made of a material having a coefficient of linear expansion close to zero,
Preferably, the housing is sealed. If the spacer is made of a material having a linear expansion coefficient close to zero while suppressing the movement of the optical resonator, the gap length d due to the temperature change can be increased.
If the enclosure housing the optical resonator is a closed system, the density is kept constant even if the pressure of the medium of the optical resonator changes when the environmental temperature changes, A change in the refractive index n due to the change is suppressed. Therefore, the transmission characteristics of the optical resonator can be further stabilized.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
FIGS. 1A and 1B show a main part of a wavelength management module according to a first embodiment of the present invention. FIG. 1A is a perspective view, and FIG. 1B is a plan view seen from above. Optical resonator 11 in the present embodiment
Reference numeral 4 denotes two rectangular substrates 31 and 31 'each having a reflection film (not shown) laminated on both end surfaces in the thickness direction of the rectangular parallelepiped block-shaped spacer 33 such that the reflection film is inside. Have been. The reflectance on the reflecting surfaces of the substrates 31, 31 'is generally set within a range of 40 to 90%.
In this embodiment, it is 90%. Although not shown in FIG. 1A, a hollow portion 122 penetrating in the thickness direction is formed in the spacer 33, and the hollow portion 122 has a groove 125.
Is communicated with the outside. Such an optical resonator 1
14, the end surfaces 114a and 114b perpendicular to the thickness direction (the laminating direction) become the light incident surface and the light emitting surface,
The inside of the hollow portion 122 serves as a medium, and the thickness direction (stacking direction) is the traveling direction of light as shown by a broken line in FIG. The hollow portion 122 is formed by the groove 125 so as to form the optical resonator 1.
Thus, the hollow portion (air layer) 122 is open. For this reason, even if the temperature changes, there is no pressure difference between the inside and the outside of the hollow portion (air layer) 122, and there is no possibility that the adhesion of the joint between the substrates 31, 31 'and the spacer 33 is impaired.

Although not shown, the optical resonator 114 is housed in a hermetically sealed housing together with an incident means for injecting parallel light into the optical resonator 114 and a means for detecting a change in transmitted light intensity. . A fixing member 41 having a substantially U-shaped planar shape is provided on the inner surface of the housing.
Are arranged in the fixing member 41 such that the bottom surface parallel to the light traveling direction is in contact with the inner surface of the housing. The inner surface of the fixing member 41 is formed to have substantially the same planar shape as the optical resonator 114 when viewed from above.
The four side surfaces parallel to the light traveling direction and the one side surface perpendicular to the light traveling direction among the four side surfaces
It is configured to be in contact with the inner surface of the. Fixing member 41
Is limited so as not to impede the incidence and emission of light at the optical resonator 114.

In this embodiment, an adhesive is used as a means for fixing the optical resonator to the housing and the fixing member 41. Reference numeral 42 in the figure indicates an adhesive,
In FIG. 1A, it is shown by oblique lines. In the present embodiment, only one of the two substrates 31 and 31 ′ constituting the optical resonator 114 is integrated with the housing and the fixing member 41 by the adhesive 42. That is, only the bottom surface and the three side surfaces of the substrate 31 ′ having the incident surface 114 a are bonded and fixed to the inner surface of the housing and the inner surface of the fixing member 41 by the adhesive 42. As the adhesive 42, for example, an epoxy resin is preferably used.

In this embodiment, the spacer 33 is made of a material having a linear expansion coefficient close to zero. Although the allowable range of the linear expansion coefficient depends on the degree of stability of the temperature characteristic to be obtained, it is approximately −0.02 × 10 ^{−6 /} K to + 0.02 × 1.
It may be within the range of about 0 ^-6 / K. Specific examples of the material constituting the spacer having a linear expansion coefficient close to zero include Zerodur (trademark) and ULE (trademark).

According to this embodiment, the bottom surface of the optical resonator 114 constituting the wavelength management module is fixed to the inner surface of the housing, and the substantially U-shaped fixing member 41 in contact with the three side surfaces of the optical resonator 114 is provided. Is provided on the inner surface of the housing, so that the optical resonator 114 is prevented from moving in a rotational direction about an axis parallel to the incident surface 114a. Further, by fixing only one substrate 31 ′ among the constituent members of the optical resonator 114 to the inner surface of the housing and the fixing member 41, the fixing position of the optical resonator 14 is caused by thermal expansion of the housing and the fixing member 41. Can be prevented from fluctuating. Therefore, it is possible to prevent the incident angle θ of the optical resonator 114 from being incident on the incident surface 114a, thereby improving the stability of the transmission characteristics of the optical resonator 114. Further, by forming the spacer 33 from a material having a linear expansion coefficient close to zero, a change in the gap length d due to a temperature change is prevented, and a refractive index n due to a temperature change can be prevented by using a closed casing. Is suppressed, thereby improving the temperature characteristics of the optical resonator and stabilizing the transmission characteristics.

In this embodiment, one of the substrates 31 'of the optical resonator 114 is bonded and fixed to both the housing and the fixing member 41. It may be bonded and fixed only to the body, or may be bonded only to the fixing member 41. In particular, in order to obtain high reliability, it is preferable that both the housing and the fixing member 41 are bonded and fixed.

FIG. 2 shows a second embodiment of the wavelength management module of the present invention.
(A) is a side view,
(B) is a plan view seen from above. 2, the same components as those of the wavelength management module of FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. This embodiment is different from the first embodiment in that an opposing member 43 having a surface opposing an emission surface 114b of the optical resonator 114 is provided in a state where the optical resonator 114 is disposed in the fixed member 41. The point is that the elastic member 44 is disposed between the facing member 43 and the emission surface 114b of the optical resonator 114. Elastic member 44
Is for urging the optical resonator 114 in a direction of pressing the optical resonator 114 against the fixing member 41. For example, a leaf spring, a spring, or the like is preferably used. Shape of opposing member 43 and elastic member 44
Is restricted so as not to hinder the incidence and emission of light at the optical resonator 114. In this embodiment, the two substrates 31 and 3 forming the optical resonator 114 are used.
Of 1 ', only the bottom surface of substrate 31' having incident surface 114a is adhesively fixed to the inner surface of the housing by an adhesive (not shown).

According to this embodiment, the same operation and effect as those of the first embodiment can be obtained.
By using the elastic member 44 as a means for fixing the fixing member 41 to the fixing member 41 and suppressing its movement, an improvement in reliability can be expected.

Hereinafter, the optical resonator 1 used in the above embodiment will be described.
An example of the manufacturing method of No. 14 will be described with reference to FIGS. 3 and 4, but the shape and manufacturing method of the optical resonator in the present invention are not limited thereto. First, two substrate base materials 121 of a size corresponding to a plurality of substrates 31 constituting one optical resonator 114 are prepared. On one surface of the substrate base material 121, a reflective film 121a is formed on the entire surface in advance. On the other hand, a spacer base material 123 having the same size as the substrate base material 121 is prepared. Base material for spacer 123
Has a plate shape with a constant thickness, and the front surface and the back surface are parallel. A plurality of hollow portions 122 penetrating in the thickness direction are formed in the base material 123 for the spacer. This hollow portion 122 forms a medium (air layer) in the optical resonator 114. The hollow portions 122 are preferably formed so as to be arranged in a matrix at predetermined intervals when the spacer base material 123 is viewed in plan. Further, in the present embodiment, the hollow portion 122 is formed in a cylindrical shape, but the cross-sectional shape of the hollow portion 122 can be changed.

Further, on the surface of the spacer base material 123, a groove portion 125 communicating with the adjacent hollow portion 122 is provided, and the outermost hollow portion 122a is formed with a groove portion 125a opening at the end face of the spacer base material 123. Is also in communication with the outside. In this embodiment, two hollow portions 125 are formed for one hollow portion 122, but it is sufficient that one hollow portion 122 communicates with another hollow portion 122 or the outside at least at one location. It may be communicated at more than one point. In this embodiment, the groove 125 is provided on the surface of the spacer base material 123. However, the groove 125 may be provided on the back surface of the spacer base material 123.
It may be provided on both the front surface and the back surface. Also, the groove 125
Instead, a horizontal hole (not shown) may be provided inside the spacer base material 123. It is preferable to use the side holes because it is not necessary to pay attention so that the groove 125 is not filled with the adhesive when the adhesive is applied to the base material 123 for the spacer.

Next, the two base materials 121 for the substrate are
The spacers 21a face each other so that they face inward, and the spacer base material 123 is sandwiched and fixed between them. Specifically, an adhesive is applied to the front and back surfaces of the spacer base material 123,
A substrate base material 121 is superposed thereon so that the reflection film 121a is in contact with the spacer base material 123, and these are adhered and fixed to obtain a laminate. Thereafter, the obtained laminated body is cut in the thickness direction between the adjacent hollow portions 122, and cut into each hollow portion 122 to obtain the optical resonator 114 as shown in FIG. 4A and 4B show an example of the optical resonator 114 obtained by cutting the laminate, wherein FIG. 4A is a perspective view, and FIG. 4B is a cross-sectional view along the line XX. In the present embodiment, since the hollow portions 122 are arranged in a matrix at predetermined intervals in the base material 123 for a spacer, a rectangular parallelepiped having one hollow portion 122 at the center is obtained by cutting the laminate into a lattice shape. Of the optical resonator 114 of the same size can be cut out.

According to the manufacturing method of this embodiment, the optical resonators conventionally assembled one by one using minute components are
Since many pieces can be manufactured at the same time, productivity is good and mass production is possible. Further, since the base material 121 for the substrate and the base material 123 for the spacer are relatively large members, the dimensional accuracy can be easily increased. By improving the dimensional accuracy of the substrate base material 121 and the spacer base material 123, the shape accuracy of the optical resonator can be improved. In particular, the accuracy of the gap length d can be improved by controlling the thickness of the spacer base material 123. By increasing the value, characteristics can be made uniform.

In the above embodiment, the optical resonator 114
Although a substantially U-shaped member protruding on the inner surface of the housing was provided as a fixing member for preventing the movement of
The optical resonator 114 can be appropriately changed as long as it can prevent the optical resonator 114 from moving in a rotation direction about an axis parallel to the incident surface 114a. For example, an optical resonator 1 is provided on the inner surface of the housing.
A recessed portion capable of accommodating the bottom of 14 without a gap may be provided.
Further, in the above embodiment, the incident surface 1 of the optical resonator 114
14a and the emission surface 114b may be reversed. Further, it is also possible to use an elastic member that urges the bottom surface of the optical resonator 114 against the inner surface of the housing without using an adhesive to fix the optical resonator 114 to the housing.

[0028]

EXAMPLES Hereinafter, the effects of the present invention will be clarified by showing specific examples. Example 1 An optical resonator was manufactured by the method shown in FIGS. First, the substrate base material 121 made of glass is
A reflective film 121a made of SiO ₂ and TiO ₂ or Ta ₂ O ₅ was formed on the entire surface on one surface by ion-assisted vapor deposition. The size of the substrate base material 121 is 50
The thickness of the reflective film 121a was set to 1 μm or less, and the thickness was 2 to 5 mm. The reflectance on the reflection surface of the base material 121 for a substrate was 90%.

Separately, a spacer base material 123 made of Zerodur (trademark, coefficient of linear expansion = 0.02 × 10 ⁻⁶ / K) was prepared. The size of the spacer 123 is 5
0-100mm, width 50-100mm, thickness 1.5-6
mm, and a cylindrical hollow portion 122 having an inner diameter of 1.5 mm was formed by ultrasonic machining. The hollow portions 122 are provided so as to be arranged in a matrix when the spacer base material 123 is viewed in a plan view. The distance between the centers of the adjacent hollow portions 122 is 3 mm, and the center of the outermost hollow portion 122a and the spacer The distance from the end face of the base material 123 was 1.5 mm.
On one surface of the spacer base material 123, each hollow portion 1
A groove 125 was formed using a dicer along a straight line passing through the center of 22 and parallel to the lateral direction of the spacer base material 123. The groove 125 had a width of 0.5 mm and a depth of 0.5 mm, and was formed from one end to the other end of the spacer base material 123 in the lateral direction.

Next, on both surfaces of the spacer base material 123,
An epoxy resin is applied as an adhesive to a thickness of about 1 μm,
On each of them, the base material 121 on the substrate was laminated and bonded so that the reflection film 121a was inside. The laminated body thus formed was cut into a lattice shape at a distance of 3 mm in the horizontal direction and at a distance of 3 mm in the vertical direction using a dicer to obtain an optical resonator 114.

In the wavelength management module 11 shown in FIG. 7, the optical resonator 114 manufactured as described above is used instead of the optical resonator 14, and the first light is transmitted through the optical resonator 14 from the collimator 12 (incident means). And the second photodiode 1
The optical path leading to 5, 17 (detection means) was housed in a sealable housing provided with a fixing member 41 as shown in FIG. 1 to produce a wavelength management module. Epoxy resin is used to fix the optical resonator 114, and only the bottom surface and three side surfaces of the substrate 31 having the incident surface 114a are fixed to the inner surface of the housing and the adhesive by the adhesive 42, as shown by oblique lines in FIG. Each of the fixing members 41 was bonded and fixed to the inner surface. Using this wavelength management module, a wavelength management system for the LD light source 1 as shown in FIG. 7 was constructed.

(Test Example 1) The wavelength-transmittance characteristic of the optical resonator 114 was measured using the wavelength management module manufactured in Example 1 above, and the center wavelength at which the transmittance peaked was determined. And the ambient temperature is 10 ℃ from 0 ℃ to 70 ℃
After the temperature was increased by 70 ° C., the fluctuation of the center wavelength when the temperature was decreased by 10 ° C. from 70 ° C. to 0 ° C. was examined. This result is shown by the solid line in FIG. In the graph of this figure, the horizontal axis is the environmental temperature,
The vertical axis indicates the center wavelength. In addition, the graph shows the measurement result at the time of temperature rise, and the graph shows the measurement result at the time of temperature drop (the same applies hereinafter). As shown in this figure, the fluctuation width of the center wavelength is suppressed to about 5 pm with respect to the temperature change of 0 to 70 ° C., and it is recognized that the stability of the characteristics with respect to the temperature change is excellent.

(Test Example 2) A wavelength management module was manufactured in the same manner as in Example 1 except that the housing was not closed and an open system was used. Using this wavelength management module,
The wavelength-transmittance characteristic of the optical resonator was measured in the same manner as in Test Example 1 above, and the change in the center wavelength due to the change in environmental temperature was examined. This result is shown by a broken line in FIG. As shown in this figure, if the housing housing the optical resonator is an open system,
The fluctuation range of the center wavelength for a temperature change of 70 ° C. is 100 p.
m.

Test Example 3 In Example 1, ULE (trademark, coefficient of linear expansion =
A wavelength management module was produced in the same manner ^{except that} 0.02 × 10 ⁻⁶ / K) was used. Using this wavelength management module, the wavelength-transmittance characteristic of the optical resonator was measured in the same manner as in Test Example 1 above, and a change in the center wavelength due to a change in environmental temperature was examined. The result is shown by a solid line in FIG. As shown in this figure, even if the material of the spacer was changed, the fluctuation width of the center wavelength with respect to a temperature change of 0 to 70 ° C. was about 5 pm, which was as good as that of Test Example 1.

(Test 4) In Example 1, ULE (trademark, coefficient of linear expansion =
0.02 × 10 ⁻⁶ / K), and a wavelength management module was produced in the same manner except that the housing was not closed and an open system was used. Using this wavelength management module, the above Test Example 1
The wavelength-transmittance characteristics of the optical resonator were measured in the same manner as described above, and the change of the center wavelength due to the environmental temperature change was examined. This result is shown by a broken line in FIG. As shown in this figure, when the housing housing the optical resonator is an open system, the fluctuation width of the center wavelength with respect to a temperature change of 0 to 70 ° C. has increased to about 120 pm.

[0036]

As described above, according to the present invention,
The transmission characteristics of the optical resonator constituting the wavelength management module can be stabilized. For example, a change in the center wavelength at which the transmittance peaks due to a temperature change of 0 to 70 ° C.
pm or less. Therefore, if the wavelength management module of the present invention using the optical resonator is applied to a wavelength management system for an LD light source, the oscillation wavelength of the LD light source can be controlled with higher accuracy. This gives L
The fluctuation width of the oscillation wavelength of the D light source can be suppressed to be small, and the wavelength interval in the WDM method is set to 25 to 50 GHz.
It is possible to satisfy the demand for high density to the extent. Further, since it is not necessary to provide a temperature sensor in the wavelength management module, size reduction and cost reduction can be realized.

[Brief description of the drawings]

1A and 1B show a first embodiment of an optical resonator according to the present invention, wherein FIG. 1A is a perspective view and FIG. 1B is a plan view.

FIGS. 2A and 2B show a second embodiment of the optical resonator according to the present invention, wherein FIG. 2A is a side view and FIG.

FIG. 3 is an explanatory view showing an embodiment of a method for manufacturing an optical resonator.

FIG. 4 is an explanatory diagram showing an embodiment of a method for manufacturing an optical resonator.

FIG. 5 is a graph showing a result of a test example regarding a temperature characteristic of the wavelength management module.

FIG. 6 is a graph showing the results of a test example regarding the temperature characteristics of the wavelength management module.

FIG. 7 is a schematic configuration diagram showing an example of a wavelength management system for an LD light source.

FIG. 8 is a schematic configuration diagram illustrating an example of an optical resonator.

FIG. 9 is a graph showing an example of transmission characteristics in an optical resonator.

FIG. 10 is a diagram illustrating a change in an incident angle θ in the optical resonator.

[Explanation of symbols]

11: wavelength management module, 12: collimator (incident means), 14, 114: optical resonator, 15: first photodiode (detection means), 21, 21 ', 31, 31': substrate, 21a, 21b ... Reflective film, 22 ... medium, 23, 33
... spacer, 41 ... fixing member, 42 ... adhesive, 44 ... elastic member, 122, 122a ... hollow portion, 125, 125a
... grooves.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Sakai 585 Tomimachi, Funabashi-shi, Chiba Sumitomo Osaka Cement Co., Ltd. New Technology Research Laboratory (72) Inventor Hironori Tokita F-term (Reference) 2G020 AA03 BA20 CA12 CB06 CB23 CB42 CC23 CD13 CD16 CD24 CD56 5F073 BA01 EA03 FA05

Claims (6)

[Claims] 1. Two substrates, one of which is a reflection surface having a predetermined reflectance, are arranged in parallel such that the reflection surfaces face each other with a medium therebetween, and are provided between the two substrates. An optical resonator having a spacer interposed therebetween, means for causing the optical signal for monitoring to enter the optical resonator as parallel light, and means for detecting a change in transmitted light intensity from the optical resonator,
An optical path from the incidence unit to the detection unit after passing through the optical resonator is accommodated in a housing, and the optical resonator is fixed on an inner surface of the housing. And a fixing member for suppressing movement of the optical resonator is provided on an inner surface of the housing. 2. Two substrates, one surface of which is a reflection surface having a predetermined reflectance, are arranged in parallel so that the reflection surfaces face each other with a medium therebetween, and are provided between the two substrates. An optical resonator having a spacer interposed therebetween, means for causing the optical signal for monitoring to enter the optical resonator as parallel light, and means for detecting a change in transmitted light intensity from the optical resonator,
An optical path from the incidence unit to the detection unit after passing through the optical resonator is accommodated in a housing, and the optical resonator is fixed on an inner surface of the housing. And a concave portion for suppressing movement of the optical resonator is provided on an inner surface of the housing. 3. The optical resonator according to claim 1, wherein only one of the constituent members of the optical resonator is adhered and fixed to the housing and / or the fixing member or the concave portion. The wavelength management module according to any one of the above. 4. An apparatus according to claim 1, wherein an elastic member is used as means for fixing said optical resonator to said housing and / or said fixing member or said concave portion. Wavelength management module. 5. The wavelength management module according to claim 1, wherein said spacer is made of a material having a linear expansion coefficient close to zero. 6. The wavelength management module according to claim 1, wherein said housing is sealed.