JP4690117B2 - Optical module - Google Patents

Description

  The present invention relates to an optical module obtained by modularizing an optical modulator that modulates an optical signal.

  Conventionally, for example, in an optical modulator module, a temperature control element (Peltier cooler) or the like has been used in order to keep the temperature of the optical modulator constant (see Patent Document 1). In addition, in order to efficiently release the heat generated from the optical modulator to the outside, the mount portion where the optical modulator is installed has a structure that can sufficiently ensure heat conduction with the module housing.

JP 2004-288951 A

  However, in the optical modulator module as described above, when heat flows in from the outside, especially when the heat flows in a direction perpendicular to the traveling direction of light, a thermal gradient is generated in the mount portion, and the light modulation is performed. The vessel will be heated unevenly. In particular, in an interference optical modulator such as a Mach-Zehnder optical modulator based on the principle of obtaining an intensity-modulated optical signal by distributing input light to two optical waveguides and controlling the phase difference between the two, When the temperature of the waveguide changes non-uniformly, the light output intensity changes, causing signal degradation. That is, the mount for ensuring heat conduction has put the optical modulator in a state that is easily affected by fluctuations in the external temperature.

  In addition, when the control electronic circuit for controlling the optical modulator is mounted inside the optical module housing, the heat generated by the control electronic circuit is non-uniformly conducted to the mount portion, and the optical modulator is non-uniformly heated. As a result, there is a risk of signal deterioration of the optical modulator.

  The present invention has been made in view of the above problems, and provides an optical module in which the output of an optical modulator does not fluctuate even when internal heat generation or fluctuation of external temperature is caused by a control electronic circuit mounted inside. With the goal.

An optical module according to a first invention for solving the above-described problem is
An optical modulator for modulating an optical signal ;
A mount mounting the optical modulator, diffuses the heat generated of the optical modulator,
A housing containing the mount, including the light modulator;
A spacer for fixing the mount inside the housing;
The cross-sectional area of the spacer in the plane perpendicular to the same direction is made smaller than the cross-sectional area of the mount in the plane perpendicular to the direction in which the mount is fixed to the housing .
The thermal conductivity of the material forming the spacer is smaller than the thermal conductivity of the material forming the housing and the mount .
That is, according to the above configuration, the contact area of the spacer in contact with the mount can be made smaller than the area of the surface in contact with the spacer of the mount, and heat inflow from the spacer to the mount can be suppressed.

An optical module according to a second invention for solving the above-described problem is
In the optical module according to the first invention,
A cross-sectional area of the spacer is 2/3 or less of a cross-sectional area of the mount.

An optical module according to a third invention for solving the above-described problem is
In the optical module according to the first or second invention,
The thermal conductivity of the material forming the spacer is 50% or less of the thermal conductivity of the material forming the housing and the mount.

An optical module according to a fourth invention for solving the above-described problem is
In the optical module according to any one of the first to third inventions,
A control electronic circuit for controlling the optical modulator is mounted inside the casing.

An optical module according to a fifth invention for solving the above-described problem is
In the optical module according to any one of the first to fourth inventions,
A stage on which the control electronic circuit is mounted is provided inside the housing independently of the mount and the spacer.

  According to the present invention, the mount on which the optical modulator is mounted is fixed to the casing via the spacer, the cross-sectional area of the spacer is made smaller than the cross-sectional area of the mount, and the thermal conductivity thereof is mounted. Since it is smaller than the conductivity, the heat flowing from the spacer to the mount is suppressed, and the cross-sectional area is larger than the spacer and the heat flowing in can be diffused to the mount having a large heat capacity. The light modulator is not affected by the heat that has flowed in. Even if there is a change in temperature, the temperature of the optical modulator can be changed uniformly by a mount having a large heat capacity. As a result, an optical module in which the output from the optical modulator does not fluctuate can be realized.

  The present invention relates to an optical module in which an optical modulator or an optical modulator and a control electronic circuit that drives the optical modulator are mounted at the same time, in order to suppress heat inflow from the optical module housing to the mount on which the optical modulator is mounted. The cross-sectional area of the spacer between the housing and the mount is configured to be smaller than the cross-sectional area of the mount, and in addition, in order to reduce heat inflow, a material with low thermal conductivity is used as the spacer material. is there. Hereinafter, some exemplary embodiments of the optical module according to the present invention will be described with reference to FIGS.

Reference example 1

1A and 1B are diagrams showing a reference example of an optical module according to the present invention. FIG. 1A is a cross-sectional view taken along line BB ′ in FIG. 1B, and FIG. FIG. 1C is a perspective view, and is a cross-sectional view taken along line AA ′ in FIG.

In the present reference example , as the optical modulator 108 to be mounted on the mount 106 shown in FIG. 1, a modulator formed on a retum niobate (LiNbO ₃ ) substrate 80 as shown in FIG. 2 is used. The modulator distributes the CW light input to the optical input waveguide 81 to the two phase control optical waveguides 83 and 85 by the optical distributor 82, and determines the phase difference between the optical waveguides as the control electrode 84. , 86 is a Mach-Zehnder type optical modulator (MZ modulator) that is controlled by an electric signal applied to 86 and is coupled by an optical coupler 87 and controls the light intensity output from the optical output waveguide 88. is there. In the MZ modulator, as described in the above principle, the output light intensity is controlled by the phase difference between the two phase control optical waveguides 83 and 85, so that only one of the optical waveguides is heated and the temperature rises. Thus, when the refractive index (phase) of only the optical waveguide on one side changes, the output light intensity changes. However, if both the optical waveguides are heated in the same manner, the phase difference between the two optical waveguides does not change even when the temperature is raised, so that the output light intensity does not change.

  That is, even if the temperature of the optical modulator changes, if the entire optical modulator changes in the same temperature, the output high intensity will not change, and at least the heat distribution in the width direction W of the optical modulator will not change. If the non-uniformity is suppressed, even if the heat distribution in the length direction L of the optical modulator has non-uniformity, it is possible to prevent a change in the output light intensity (see FIG. 2).

The optical module of the present reference example includes a module housing composed of a module outer wall 101 and a plate 102, and includes an optical fiber 104 for light input / output and an optical fiber fixing sleeve 103. The electrical signal is supplied from the electrical connector 109 to the optical modulator 108 through the wiring board 111 formed of ceramic having high thermal insulation. An optical fiber 104 for guiding input / output light is directly coupled to the optical modulator 108. The optical modulator 108 is mounted on a mount 106, and the mount 106 is fixed to the plate 102 of the module housing using a spacer 112, and these are accommodated inside the module housing.

Here, the module outer wall 101, the plate 102, and the mount 106 are made of a material having good thermal conductivity, such as copper tungsten (CuW, thermal conductivity˜3.7 × 10 ⁻³ J / cm / s / K). Formed and made to improve heat conduction. The spacer 112 is made of the same material, but the cross-sectional area S _{s in the} plane perpendicular to the direction F for fixing the mount 106 to the plate 102 is smaller than the cross-sectional area S _m of the mount in the plane perpendicular to the same direction F. as it will have been set to the area of 2/3 or less of the cross-sectional area S _m. That is, the contact area of the spacer 112 in contact with the mount 106 is made smaller than the area of the surface of the mount 106 in contact with the spacer 112. Therefore, the heat that is about to flow from the plate 102 toward the optical modulator 108 is difficult to flow toward the optical modulator 108 because the cross-sectional area of the spacer 112 is small. Even if there is an influence, it has only an effect of heating the optical modulator 108 uniformly, and does not affect the light output intensity.

  Since the optical modulator 108 hardly generates heat or generates a small amount of heat, the generated heat is diffused by the mount 106 having a large heat capacity, and a local temperature rise of the optical modulator 108 is avoided. be able to. The cross-sectional area of the spacer 112 is preferably 2/3 or less of the cross-sectional area of the mount 106, more preferably 1/2 or less, and most preferably 1/4 or less.

FIG. 3 is a diagram showing an example of an embodiment of an optical module according to the present invention. FIG. 3A is a cross-sectional view taken along line BB ′ in FIG. 3B, and FIG. FIG. 3C is a cross-sectional view taken along the line AA ′ of FIG. 3B.

Also in the present embodiment, as the optical modulator 108, a modulator formed on a recombination niobate (LiNbO ₃ ) substrate 80 as shown in FIG. The modulator distributes the CW light input to the optical input waveguide 81 to the two phase control optical waveguides 83 and 85 by the optical distributor 82, and determines the phase difference between the optical waveguides as the control electrode 84. , 86 is a Mach-Zehnder type optical modulator (MZ modulator) that is controlled by an electric signal applied to 86 and is coupled by an optical coupler 87 and controls the light intensity output from the optical output waveguide 88. is there. In the MZ modulator, as described in the above principle, the output light intensity is controlled by the phase difference between the two phase control optical waveguides 83 and 85, so that only one of the optical waveguides is heated and the temperature rises. Thus, when the refractive index (phase) of only the optical waveguide on one side changes, the output light intensity changes. However, if both the optical waveguides are heated in the same manner, the phase difference between the two optical waveguides does not change even when the temperature is raised, so that the output light intensity does not change.

  That is, even if the temperature of the optical modulator changes, if the entire optical modulator changes in the same temperature, the output high intensity will not change, and at least the heat distribution in the width direction W of the optical modulator will not change. If the non-uniformity is suppressed, even if the heat distribution in the length direction L of the optical modulator has non-uniformity, it is possible to prevent a change in the output light intensity (see FIG. 2).

  The optical module of the present embodiment includes a module housing composed of a module outer wall 101 and a plate 102, and includes an optical fiber 104 for light input / output and an optical fiber fixing sleeve 103. The electrical signal is supplied from the electrical connector 109 to the optical modulator 108 through the wiring board 111 formed of ceramic having high thermal insulation. An optical fiber 104 for guiding input / output light is directly coupled to the optical modulator 108. The optical modulator 108 is mounted on a mount 106, and the mount 106 is fixed to the plate 102 of the module housing using a spacer 113, and these are housed inside the module housing.

Here, the module outer wall 101, the plate 102, and the mount 106 are formed of a material having good thermal conductivity, such as copper tungsten (CuW, thermal conductivity˜3.7 × 10 ⁻³ J / cm / s / K). And is made to improve heat conduction. The spacer 113 is a material having a thermal conductivity of 50% or less compared to the material constituting the module housing, for example, brass (brass (Cu 70%, Zn 30%), thermal conductivity up to 0.96 × 10 ⁻³ J / cm. / s / K) or stainless steel (thermal conductivity˜0.25 × 10 ⁻³ J / cm / s / K). Further, the cross-sectional area S _s of the spacer 113 in a plane perpendicular to the direction F to secure the mount 106 to the plate 102, so as to be smaller than the cross-sectional area S _m of the mount in a plane perpendicular to the same direction F, the cross-sectional area S _m Of 2/3 or less. That is, the contact area of the spacer 113 in contact with the mount 106 is made smaller than the area of the surface of the mount 106 in contact with the spacer 113. Accordingly, the heat that tends to flow from the plate 102 toward the optical modulator 108 is less likely to flow toward the optical modulator 108 due to the small cross-sectional area of the spacer 113 and the poor thermal conductivity of the spacer 113. Since the light is not diffused by the mount 106 having a large heat capacity without affecting the light modulator 108, the light modulator 108 can only be heated uniformly even when there is an influence, and the light output intensity is affected. Will not affect.

  Since the optical modulator 108 hardly generates heat or generates a small amount of heat, the generated heat is diffused by the mount 106 having a large heat capacity, and a local temperature rise of the optical modulator 108 is avoided. be able to. The cross-sectional area of the spacer 113 is preferably 2/3 or less of the cross-sectional area of the mount 106, more preferably 1/2 or less, and most preferably 1/4 or less. Further, the thermal conductivity of the material of the spacer 113 is desirably 50% or less, more desirably 25% or less, and most desirably 10% or less, compared to the thermal conductivity of the material such as the mount 106.

Reference example 2

4A and 4B are diagrams showing another reference example of the optical module according to the present invention. FIG. 4A is a cross-sectional view taken along line BB ′ in FIG. 4B, and FIG. FIG. 4C is a cross-sectional view taken along the line AA ′ of FIG. 4B.

In this reference example , as the optical modulator 208 mounted on the mount 206 shown in FIG. 4, a modulator formed on the semiconductor substrate 90 as shown in FIG. 5 is used. The modulator distributes the CW light input to the optical input waveguide 91 to the two phase control optical waveguides 93 and 95 by the optical distributor 92, and determines the phase difference between the optical waveguides to the control electrode 94. , A Mach-Zehnder type optical modulator (MZ modulator) which is controlled by an electric signal applied to 96 and is coupled by an optical coupler 97 and controls the light intensity output from the optical output waveguide 98. is there. In the MZ modulator, since the output light intensity is controlled by the phase difference between the two phase control optical waveguides 93 and 95 as described in the above principle, only one of the optical waveguides is heated and the temperature rises. Thus, when the refractive index (phase) of only the optical waveguide on one side changes, the output light intensity changes. However, if both the optical waveguides are heated in the same manner, the phase difference between the two optical waveguides does not change even when the temperature is raised, so that the output light intensity does not change.

  That is, even if the temperature of the optical modulator changes, if the entire optical modulator changes in the same temperature, the output high intensity will not change, and at least the heat distribution in the width direction W of the optical modulator will not change. If the non-uniformity is suppressed, it is possible to prevent a change in the output light intensity even if the heat distribution in the length direction L of the optical modulator is non-uniform (see FIG. 5).

The optical module of the present reference example includes a module housing composed of a module outer wall 201 and a plate 202, and an optical fiber 204 for light input / output and an optical fiber fixing sleeve 203. The electrical signal is supplied from the electrical connector 209 to the semiconductor optical modulator 208 through the wiring board 211 formed of ceramic having high thermal insulation. The optical fiber 204 for guiding the input / output light is coupled to the optical modulator 208 by a coupling lens 207 provided on the optical modulator installation mount 206. The optical modulator 208 is mounted on a mount 206, and the mount 206 is fixed to the plate 202 of the module housing using a spacer 212, and these are housed inside the module housing.

Here, the module outer wall 201, the plate 202, and the mount 206 are formed of a material having good thermal conductivity, such as copper tungsten (CuW, thermal conductivity˜3.7 × 10 ⁻³ J / cm / s / K). And is made to improve heat conduction. The spacer 212 is formed of the same material, but the cross-sectional area S _{s in the} plane perpendicular to the direction F for fixing the mount 206 to the plate 202 is smaller than the cross-sectional area S _m of the mount in the plane perpendicular to the same direction F. as it will have been set to the area of 2/3 or less of the cross-sectional area S _m. That is, the contact area of the spacer 212 that contacts the mount 206 is made smaller than the area of the surface of the mount 206 that contacts the spacer 212. Therefore, the heat that is about to flow from the plate 202 toward the optical modulator 208 is less likely to flow toward the optical modulator 208 because the cross-sectional area of the spacer 212 is small. Even if there is an influence, it has only an effect of heating the optical modulator 208 uniformly, and does not affect the light output intensity.

  The optical modulator 208 hardly generates heat or generates a small amount of heat. Therefore, the heat generation is diffused by the mount 206 having a large heat capacity, and a local temperature rise of the optical modulator 208 is avoided. be able to. The cross-sectional area of the spacer 212 is preferably 2/3 or less of the cross-sectional area of the mount 206, more preferably 1/2 or less, and most preferably 1/4 or less.

  FIG. 6 is a view showing another example of the embodiment of the optical module according to the present invention. FIG. 6A is a cross-sectional view taken along the line BB ′ of FIG. ) Is a top perspective view, and FIG. 6C is a cross-sectional view taken along the line AA ′ in FIG. 6B.

  Also in this embodiment, a modulator formed on the semiconductor substrate 90 as shown in FIG. The modulator distributes the CW light input to the optical input waveguide 91 to the two phase control optical waveguides 93 and 95 by the optical distributor 92, and determines the phase difference between the optical waveguides to the control electrode 94. , A Mach-Zehnder type optical modulator (MZ modulator) which is controlled by an electric signal applied to 96 and is coupled by an optical coupler 97 and controls the light intensity output from the optical output waveguide 98. is there. In the MZ modulator, since the output light intensity is controlled by the phase difference between the two phase control optical waveguides 93 and 95 as described in the above principle, only one of the optical waveguides is heated and the temperature rises. Thus, when the refractive index (phase) of only the optical waveguide on one side changes, the output light intensity changes. However, if both the optical waveguides are heated in the same manner, the phase difference between the two optical waveguides does not change even when the temperature is raised, so that the output light intensity does not change.

  That is, even if the temperature of the optical modulator changes, if the entire optical modulator changes in the same temperature, the output high intensity will not change, and at least the heat distribution in the width direction W of the optical modulator will not change. If the non-uniformity is suppressed, it is possible to prevent a change in the output light intensity even if the heat distribution in the length direction L of the optical modulator is non-uniform (see FIG. 5).

  The optical module of the present embodiment includes a module housing composed of a module outer wall 201 and a plate 202, and includes a light input / output optical fiber 204 and an optical fiber fixing sleeve 203. The electrical signal is supplied from the electrical connector 209 to the semiconductor optical modulator 208 through the wiring board 211 formed of ceramic having high thermal insulation. The optical fiber 204 for guiding the input / output light is coupled to the optical modulator 208 by a coupling lens 207 provided on the optical modulator installation mount 206. The optical modulator 208 is mounted on a mount 206, and the mount 206 is fixed to the plate 202 of the module housing using a spacer 213, and these are housed inside the module housing.

Here, the module outer wall 201, the plate 202, and the mount 206 are formed of a material having good thermal conductivity, such as copper tungsten (CuW, thermal conductivity˜3.7 × 10 ⁻³ J / cm / s / K). And is made to improve heat conduction. The spacer 213 is a material having a thermal conductivity of 50% or less compared to the material constituting the module housing, for example, brass (brass (Cu 70%, Zn 30%), thermal conductivity up to 0.96 × 10 ⁻³ J / cm. / s / K) or stainless steel (thermal conductivity˜0.25 × 10 ⁻³ J / cm / s / K). Further, the cross-sectional area S _s of the spacer 213 in a plane perpendicular to the direction F to secure the mount 206 to the plate 202, so as to be smaller than the cross-sectional area S _m of the mount in a plane perpendicular to the same direction F, the cross-sectional area S _m Of 2/3 or less. That is, the contact area of the spacer 213 that contacts the mount 206 is smaller than the area of the surface of the mount 206 that contacts the spacer 213. Accordingly, the heat that tends to flow from the plate 202 toward the optical modulator 208 is less likely to flow toward the optical modulator 208 due to the small cross-sectional area of the spacer 213 and the poor thermal conductivity of the spacer 213. Since the light is not diffused by the mount 206 having a large heat capacity without affecting the light modulator 208, even if there is an influence, the light modulator 208 can only be heated uniformly, affecting the light output intensity. Will not affect.

  The optical modulator 208 hardly generates heat or generates a small amount of heat. Therefore, the heat generation is diffused by the mount 206 having a large heat capacity, and a local temperature rise of the optical modulator 208 is avoided. be able to. The cross-sectional area of the spacer 213 is preferably 2/3 or less of the cross-sectional area of the mount 206, more preferably 1/2 or less, and most preferably 1/4 or less. In addition, the thermal conductivity of the material of the spacer 213 is preferably 50% or less, more preferably 25% or less, and most preferably 10% or less, compared to the thermal conductivity of the material such as the mount 206.

In Reference Examples 1 and 2 and Examples 1 and 2, the control IC for controlling the optical modulator is disposed outside the optical module housing. However, as described above, the optical modulator is Since the mount to be mounted is fixed to the housing side via a spacer, if the control IC is placed inside the optical module housing unless it is a place where heat is transferred directly to the optical modulator, It does not affect the output intensity. However, in this case, it is desirable to efficiently release the heat generated from the control IC to the outside of the optical module housing. Examples of such embodiments are shown in Reference Examples 3 to 4 and Examples 3 to 4 described later. Such a configuration is conceivable.

Reference example 3

FIG. 7 is a diagram showing another reference example of the optical module according to the present invention. FIG. 7A is a cross-sectional view taken along line BB ′ in FIG. 7B, and FIG. FIG. 7C is a cross-sectional view taken along the line AA ′ of FIG. 7B.

Also in this reference example , as the optical modulator 308, a modulator formed on a recombination niobate (LiNbO ₃ ) substrate 80 as shown in FIG. The modulator distributes the CW light input to the optical input waveguide 81 to the two phase control optical waveguides 83 and 85 by the optical distributor 82, and determines the phase difference between the optical waveguides as the control electrode 84. , 86 is a Mach-Zehnder type optical modulator (MZ modulator) that is controlled by an electric signal applied to 86 and is coupled by an optical coupler 87 and controls the light intensity output from the optical output waveguide 88. is there. In the MZ modulator, as described in the above principle, the output light intensity is controlled by the phase difference between the two phase control optical waveguides 83 and 85, so that only one of the optical waveguides is heated and the temperature rises. Thus, when the refractive index (phase) of only the optical waveguide on one side changes, the output light intensity changes. However, if both the optical waveguides are heated in the same manner, the phase difference between the two optical waveguides does not change even when the temperature is raised, so that the output light intensity does not change.

  That is, even if the temperature of the optical modulator changes, if the entire optical modulator changes in the same temperature, the output high intensity will not change, and at least the heat distribution in the width direction W of the optical modulator will not change. If the non-uniformity is suppressed, even if the heat distribution in the length direction L of the optical modulator has non-uniformity, it is possible to prevent a change in the output light intensity (see FIG. 2).

The optical module of this reference example is provided with a stage 305 for disposing a light input / output optical fiber 304, an optical fiber fixing sleeve 303, and a control IC 310 in a module housing composed of a module outer wall 301 and a plate 302. is there. The control IC 310 on the stage 305 is configured to supply an electrical signal through the electrical connector 309, and the control signal from the control IC 310 is optically modulated through the wiring board 311 formed of ceramic having high thermal insulation. To the container 308. An optical fiber 304 for guiding input / output light is directly coupled to the optical modulator 308. The light modulator 308 is mounted on a mount 306, and the mount 306 is fixed to the plate 302 of the module housing using a spacer 312, and the stage 305 is independent of the mount 306 and the spacer 312. These are fixed to the plate 302 and are housed inside the module housing.

Here, the module outer wall 301, the plate 302, the stage 305, and the mount 306 have good thermal conductivity, such as copper tungsten (CuW, thermal conductivity˜3.7 × 10 ⁻³ J / cm / s / K). It is made of material and made to improve heat conduction. The spacer 312 is made of the same material, but the cross-sectional area S _{s in the} plane perpendicular to the direction F for fixing the mount 306 to the plate 302 is smaller than the cross-sectional area S _m of the mount in the plane perpendicular to the same direction F. as it will have been set to the area of 2/3 or less of the cross-sectional area S _m. That is, the contact area of the spacer 312 that contacts the mount 306 is made smaller than the area of the surface of the mount 306 that contacts the spacer 312. Accordingly, the heat that is about to flow from the plate 302 toward the optical modulator 308 is less likely to flow toward the optical modulator 308 because the cross-sectional area of the spacer 312 is small. Even if there is an influence, the light modulator 308 is only heated uniformly and does not affect the light output intensity. The heat generated from the control IC 310 is efficiently released to the outside of the module through the stage 305 and the plate 302 having good thermal conductivity, so that the heat is not directly transferred to the optical modulator 308. Even if the light flows in the direction of the optical modulator 308, heat is transmitted through the spacer 312 and the mount 306, and as described above, heat transfer to the mount 306 is suppressed by the spacer 312 and heat is transmitted by the mount 306. Since the diffusion is performed, the light output intensity is not affected.

  The optical modulator 308 generates little heat or generates a small amount of heat, so that the heat generation is diffused by the mount 306 having a large heat capacity to avoid a local temperature rise of the light modulator 308. be able to. The cross-sectional area of the spacer 312 is preferably 2/3 or less of the cross-sectional area of the mount 306, more preferably 1/2 or less, and most preferably 1/4 or less.

  FIG. 8 is a diagram showing another example of the embodiment of the optical module according to the present invention. FIG. 8A is a cross-sectional view taken along the line BB ′ in FIG. ) Is a top perspective view, and FIG. 8C is a cross-sectional view taken along the line AA ′ in FIG. 8B.

Also in this embodiment, as the optical modulator 308, a modulator formed on a reconditioned niobate (LiNbO ₃ ) substrate 80 as shown in FIG. The modulator distributes the CW light input to the optical input waveguide 81 to the two phase control optical waveguides 83 and 85 by the optical distributor 82, and determines the phase difference between the optical waveguides as the control electrode 84. , 86 is a Mach-Zehnder type optical modulator (MZ modulator) that is controlled by an electric signal applied to 86 and is coupled by an optical coupler 87 and controls the light intensity output from the optical output waveguide 88. is there. In the MZ modulator, as described in the above principle, the output light intensity is controlled by the phase difference between the two optical waveguides for phase control. Therefore, only the optical waveguide on one side is heated and the temperature rises. When the refractive index (phase) of only the optical waveguide changes, the output light intensity changes. However, if both the optical waveguides are heated in the same manner, the phase difference between the two optical waveguides does not change even when the temperature is raised, so that the output light intensity does not change.

  That is, even if the temperature of the optical modulator changes, if the entire optical modulator changes in the same temperature, the output high intensity will not change, and at least the heat distribution in the width direction W of the optical modulator will not change. If the non-uniformity is suppressed, even if the heat distribution in the length direction L of the optical modulator has non-uniformity, it is possible to prevent a change in the output light intensity (see FIG. 2).

  The optical module of the present embodiment is provided with a stage 305 for arranging a light input / output optical fiber 304, an optical fiber fixing sleeve 303, and a control IC 310 in a module housing composed of a module outer wall 301 and a plate 302. is there. The control IC 310 on the stage 305 is configured to supply an electrical signal through the electrical connector 309. The control signal from the control IC 310 is optically modulated through the wiring board 311 formed of ceramic having high thermal insulation. To the container 308. An optical fiber 304 for guiding input / output light is directly coupled to the optical modulator 308. The optical modulator 308 is mounted on a mount 306, the mount 306 is fixed to the plate 302 of the module housing using a spacer 313, and the stage 305 is independent of the mount 306 and the spacer 313. These are fixed to the plate 302 and are housed inside the module housing.

Here, the module outer wall 301, the plate 302, the stage 1 305, and the mount 306 have good thermal conductivity, for example, copper tungsten (CuW, thermal conductivity˜3.7 × 10 ⁻³ J / cm / s / K). Etc., and is made so as to improve heat conduction. The spacer 313 is a material having a thermal conductivity of 50% or less compared to the material constituting the module housing, for example, brass (brass (Cu 70%, Zn 30%), thermal conductivity up to 0.96 × 10 ⁻³ J / cm. / s / K) or stainless steel (thermal conductivity˜0.25 × 10 ⁻³ J / cm / s / K). Further, the cross-sectional area S _s of the spacer 313 in a plane perpendicular to the direction F to fix the mount 306 to the plate 302, so as to be smaller than the cross-sectional area S _m of the mount in a plane perpendicular to the same direction F, the cross-sectional area S _m Of 2/3 or less. That is, the contact area of the spacer 313 in contact with the mount 306 is made smaller than the area of the surface of the mount 306 in contact with the spacer 313. Therefore, the heat that tends to flow from the plate 302 toward the optical modulator 308 is less likely to flow toward the optical modulator 308 due to the small cross-sectional area of the spacer 313 and the poor thermal conductivity of the spacer 313. Since it is diffused by the mount 306 having a large heat capacity without exerting a great influence on the optical modulator 308, even if there is an influence, it has only an effect of heating the optical modulator 308 uniformly and affects the light output intensity. Will not affect. The heat generated from the control IC 310 is efficiently released to the outside of the module through the stage 305 and the plate 302 having good thermal conductivity, so that the heat is not directly transferred to the optical modulator 308. Even if the light flows in the direction of the optical modulator 308, heat is transmitted through the spacer 313 and the mount 306, and as described above, the heat conduction to the mount 306 is suppressed by the spacer 313 and the mount 306 heats. Since the diffusion is performed, the light output intensity is not affected.

  Note that the optical modulator 308 generates little heat, or the heat generation is minimal, so that the heat is diffused by the mount 306 having a large heat capacity, and a local temperature rise of the light modulator 308 is avoided. be able to. The cross-sectional area of the spacer 313 is preferably 2/3 or less of the cross-sectional area of the mount 306, more preferably 1/2 or less, and most preferably 1/4 or less. In addition, the thermal conductivity of the material of the spacer 313 is preferably 50% or less, more preferably 25% or less, and most preferably 10% or less, compared to the thermal conductivity of the material such as the mount 306.

Reference example 4

FIG. 9 is a diagram showing another reference example of the optical module according to the present invention. FIG. 9A is a cross-sectional view taken along the line BB ′ in FIG. 9B, and FIG. FIG. 9C is a cross-sectional view taken along line AA ′ of FIG. 9B.

Also in this reference example , a modulator formed on the semiconductor substrate 90 as shown in FIG. In the optical modulator, the CW light input to the optical input waveguide 91 is distributed to the two phase control optical waveguides 93 and 95 by the optical distributor 92, and the phase difference between the optical waveguides is determined as the control electrode. Mach-Zehnder type optical modulator (MZ modulator) based on the principle of controlling the intensity of light output from the optical output waveguide 98 by being controlled by an electric signal applied to 94 and 96 and coupled by the optical coupler 97. It is. In the MZ modulator, since the output light intensity is controlled by the phase difference between the two phase control optical waveguides 93 and 95 as described in the above principle, only one of the optical waveguides is heated and the temperature rises. Thus, when the refractive index (phase) of only the optical waveguide on one side changes, the output light intensity changes. However, if both the optical waveguides are heated in the same manner, the phase difference between the two optical waveguides does not change even when the temperature is raised, so that the output light intensity does not change.

  That is, even if the temperature of the optical modulator changes, if the entire optical modulator changes in the same temperature, the output high intensity will not change, and at least the heat distribution in the width direction W of the optical modulator will not change. If the non-uniformity is suppressed, it is possible to prevent a change in the output light intensity even if the heat distribution in the length direction L of the optical modulator is non-uniform (see FIG. 5).

The optical module of this reference example is provided with a stage 405 for arranging a light input / output optical fiber 404, an optical fiber fixing sleeve 403, and a control IC 410 in a module housing composed of a module outer wall 401 and a plate 402. is there. The control IC 410 on the stage 405 is configured to supply an electrical signal through the electrical connector 409, and the control signal from the control IC 410 is transmitted through the wiring board 411 made of ceramic having high thermal insulation properties. The signal is supplied to the modulator 408. An optical fiber 404 for guiding input / output light is coupled to the optical modulator 408 by a coupling lens 407 provided on the optical modulator installation mount 406. The optical modulator 408 is mounted on a mount 406, the mount 406 is fixed to the plate 402 of the module housing using a spacer 412, and the stage 405 is independent of the mount 406 and the spacer 412. These are fixed to the plate 402, and these are accommodated inside the module housing.

Here, the module outer wall 401, the plate 402, the stage 405, and the mount 406 have good thermal conductivity, such as copper tungsten (CuW, thermal conductivity˜3.7 × 10 ⁻³ J / cm / s / K). It is made of material and made to improve heat conduction. The spacer 412 is formed of the same material, but the cross-sectional area S _{s in the} plane perpendicular to the direction F for fixing the mount 406 to the plate 402 is smaller than the cross-sectional area S _m of the mount in the plane perpendicular to the same direction F. as it has been set to the area of 2/3 or less of the cross-sectional area S _m. That is, the contact area of the spacer 412 in contact with the mount 406 is made smaller than the area of the surface of the mount 406 in contact with the spacer 412. Accordingly, the heat that tends to flow from the plate 402 toward the optical modulator 408 is difficult to flow in the direction of the optical modulator 408 because the cross-sectional area of the spacer 412 is small, and has a great influence on the optical modulator 408. Furthermore, since the light is diffused by the mount 406 having a large heat capacity, even if there is an influence, the light modulator 408 is only heated uniformly and does not affect the light output intensity. In addition, since the heat generated from the control IC 410 is efficiently released to the outside of the module through the stage 405 and the plate 402 having good thermal conductivity, the generated heat is not directly transferred to the optical modulator 408. Even if the light flows in the direction of the optical modulator 408, heat is transmitted through the spacer 412 and the mount 406, and as described above, heat conduction to the mount 406 is suppressed by the spacer 412 and heat is transmitted by the mount 406. Since the diffusion is performed, the light output intensity is not affected.

  The optical modulator 408 hardly generates heat or generates a small amount of heat, so that the heat generation is diffused by the mount 406 having a large heat capacity, and a local temperature rise of the optical modulator 408 is avoided. be able to. The cross-sectional area of the spacer 412 is preferably 2/3 or less of the cross-sectional area of the mount 106, more preferably 1/2 or less, and most preferably 1/4 or less.

  FIG. 10 is a diagram showing another example of the embodiment of the optical module according to the present invention. FIG. 10 (a) is a cross-sectional view taken along the line BB ′ of FIG. 10 (b), and FIG. ) Is a top perspective view, and FIG. 10C is a cross-sectional view taken along the line AA ′ in FIG. 10B.

  Also in this embodiment, as the optical modulator 408, a modulator formed on the semiconductor substrate 90 as shown in FIG. In the optical modulator, the CW light input to the optical input waveguide 91 is distributed to the two phase control optical waveguides 93 and 95 by the optical distributor 92, and the phase difference between the optical waveguides is determined as the control electrode. Mach-Zehnder type optical modulator (MZ modulator) based on the principle of controlling the intensity of light output from the optical output waveguide 98 by being controlled by an electric signal applied to 94 and 96 and coupled by the optical coupler 97. It is. In the MZ modulator, as described in the above principle, the output light intensity is controlled by the phase difference between the two optical waveguides for phase control. Therefore, only the optical waveguide on one side is heated and the temperature rises. When the refractive index (phase) of only the optical waveguide changes, the output light intensity changes. However, if both the optical waveguides are heated in the same manner, the phase difference between the two optical waveguides does not change even when the temperature is raised, so that the output light intensity does not change.

  That is, even if the temperature of the optical modulator changes, if the entire optical modulator changes in the same temperature, the output high intensity will not change, and at least the heat distribution in the width direction W of the optical modulator will not change. If the non-uniformity is suppressed, it is possible to prevent a change in the output light intensity even if the heat distribution in the length direction L of the optical modulator is non-uniform (see FIG. 5).

  The optical module according to the present embodiment is provided with a stage 405 for arranging a light input / output optical fiber 404, an optical fiber fixing sleeve 403, and a control IC 410 in a module housing composed of a module outer wall 401 and a plate 402. is there. The control IC 410 on the stage 405 is configured to supply an electrical signal through the electrical connector 409, and the control signal from the control IC 410 is transmitted through the wiring board 411 made of ceramic having high thermal insulation properties. The signal is supplied to the modulator 408. The optical fiber 404 for guiding the input / output light is coupled to the optical modulator 408 by a coupling lens 407 provided on the optical modulator installation mount 406. The optical modulator 408 is mounted on a mount 406, the mount 406 is fixed to the plate 402 of the module housing using a spacer 413, and the stage 405 is independent of the mount 406 and the spacer 413. These are fixed to the plate 402, and these are accommodated inside the module housing.

Here, the module outer wall 401, the plate 402, the stage 405, and the mount 406 have good thermal conductivity, such as copper tungsten (CuW, thermal conductivity˜3.7 × 10 ⁻³ J / cm / s / K). It is made of material and made to improve heat conduction. The spacer 413 is made of a material having a thermal conductivity of 50% or less compared to the material constituting the module housing, such as brass (brass (Cu 70%, Zn 30%), thermal conductivity up to 0.96 × 10 ⁻³ J / cm. / s / K) or stainless steel (thermal conductivity˜0.25 × 10 ⁻³ J / cm / s / K). Further, the cross-sectional area S _s of the spacer 413 in a plane perpendicular to the direction F to secure the mount 406 to the plate 402, so as to be smaller than the cross-sectional area S _m of the mount in a plane perpendicular to the same direction F, the cross-sectional area S _m Of 2/3 or less. That is, the contact area of the spacer 413 that contacts the mount 406 is smaller than the area of the surface of the mount 406 that contacts the spacer 413. Accordingly, the heat that tends to flow from the plate 402 toward the optical modulator 408 is less likely to flow toward the optical modulator 408 due to the small cross-sectional area of the spacer 413 and the poor thermal conductivity of the spacer 413. Since the light modulator 408 does not have a great influence and is diffused by the mount 406 having a large heat capacity, even if there is an influence, the light modulator 408 has only an effect of heating uniformly and affects the light output intensity. Will not affect. In addition, since the heat generated from the control IC 410 is efficiently released to the outside of the module through the stage 405 and the plate 402 having good thermal conductivity, the generated heat is not directly transferred to the optical modulator 408. Even if the light flows in the direction of the optical modulator 408, heat transfer to the mount 406 is suppressed by the spacer 413 and heat is transmitted to the mount 406 by the spacer 413 as described above. Since the diffusion is performed, the light output intensity is not affected.

  The optical modulator 408 hardly generates heat or generates a small amount of heat, so that the heat generation is diffused by the mount 406 having a large heat capacity, and a local temperature rise of the optical modulator 408 is avoided. be able to. The cross-sectional area of the spacer 413 is preferably 2/3 or less of the cross-sectional area of the mount 406, more preferably 1/2 or less, and most preferably 1/4 or less. In addition, the thermal conductivity of the material of the spacer 413 is preferably 50% or less, more preferably 25% or less, and most preferably 10% or less, compared to the thermal conductivity of the mount material.

  In the present invention, the optical modulator has been described as an example. However, the present invention can be applied to any optical module as long as an optical element whose characteristics are affected by thermal fluctuation is modularized.

It is a figure which shows the reference example (reference example 1) of the optical module which concerns on this invention. FIG. 2 is a principle diagram of a re-Chemical Niobate Mach-Zehnder optical modulator used in the optical module according to the present invention. It is a figure which shows an example (Example 1) of embodiment of the optical module which concerns on this invention. 1 is a principle diagram of a semiconductor Mach-Zehnder optical modulator used in an optical module according to the present invention. It is a figure which shows the other reference example (reference example 2) of the optical module which concerns on this invention. It is a figure which shows another example ( Example 2 ) of embodiment of the optical module which concerns on this invention. It is a figure which shows the other reference example (reference example 3) of the optical module which concerns on this invention. It is a figure which shows another example ( Example 3 ) of embodiment of the optical module which concerns on this invention. It is a figure which shows the other reference example (reference example 4) of the optical module which concerns on this invention. It is a figure which shows another example ( Example 4 ) of embodiment of the optical module which concerns on this invention.

80: Re-Chemical Niobate substrate 81, 91: Optical input waveguide 82, 92: Optical distributor 83, 85, 93, 95: Phase control optical waveguides 84, 86, 94, 96: Control electrode 87, 97: Optical coupler 88, 98: Optical output waveguide 90: Semiconductor substrate 101, 201, 301, 401: Module outer wall 102, 202, 302, 402: Plate 103, 203, 303, 403: Optical fiber fixing sleeve 104, 204, 304, 404: Optical fibers for light input / output 106, 206, 306, 406: Optical modulator installation mounts 108, 208, 308, 408: Optical modulators 109, 209, 309, 409: Electrical connectors 111, 211 311, 411: wiring boards 112, 212, 312, 412: spacers 113 and 213 made of the same material as the module housing 313, 413: the module housing spacer by poor heat-conductive material than the material 207,407: coupling lens 305, 405: Stage 310, 410: Control IC (control electronics)

Claims (5)

An optical modulator for modulating an optical signal ;
A mount mounting the optical modulator, diffuses the heat generated of the optical modulator,
A housing containing the mount, including the light modulator;
A spacer for fixing the mount inside the housing;
The cross-sectional area of the spacer in the plane perpendicular to the same direction is made smaller than the cross-sectional area of the mount in the plane perpendicular to the direction in which the mount is fixed to the housing .
An optical module characterized in that a thermal conductivity of a material forming the spacer is smaller than a thermal conductivity of a material forming the casing and the mount . The optical module according to claim 1,
An optical module, wherein a cross-sectional area of the spacer is 2/3 or less of a cross-sectional area of the mount. The optical module according to claim 1 or 2 ,
An optical module, wherein a thermal conductivity of a material forming the spacer is 50% or less of a thermal conductivity of a material forming the casing and the mount. The optical module according to any one of claims 1 to 3 ,
An optical module, wherein a control electronic circuit for controlling an optical modulator is mounted inside the casing. The optical module according to any one of claims 1 to 4 ,
An optical module, wherein a stage on which the control electronic circuit is mounted is provided inside the housing independently of the mount and the spacer.

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