JP2002350792A - Ea modulator module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate characteristic degradation due to the inductance component of an inductance element connecting a driving circuit and a stripline and the capacitance component of an EA modulator. SOLUTION: This EA modulator module is provided with an EA modulator 11 being a semiconductor element whose absorption coefficient is changed in accordance with an electric field to be impressed and which modulates the intensity of an optical signal, a first inductance element 12 whose one end is connected to the voltage applying end of the EA modulator 11, a load resistance element 13 of 50 Ω which is connected between the other end of the first inductance element 12 and ground, a stripline 14 whose one end is connected to the voltage applying end of the EA modulator 11, a capacitance element 15 which is connected between the other end of the stripline 14 and ground, a driving circuit 16 which outputs a voltage signal for driving the EA modulator 11 and a connection wire 17 which connects the output end of the driving circuit 16 and the other end of the stripline 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an electro-absorption (hereinafter referred to as "EA") modulator module used for intensity-modulating an optical signal in an optical transmitter in an optical communication system.

[0002]

2. Description of the Related Art An EA modulator is a capacitive element (diode) having the same pn junction double heterostructure as a laser diode (hereinafter referred to as "LD"). When a negative bias is applied, it is absorbed by the Franz-Keldysh effect. The intensity of the optical signal is modulated using the change in the coefficient.

[0003] Unlike the case of directly modulating the oscillation light of the LD, the EA modulator does not involve the movement of the carrier at the time of modulation, and therefore has excellent responsiveness and can be driven and controlled at high speed. Therefore, in the recent optical communication field, LD
External modulation using this EA modulator has been used instead of direct modulation.

Here, a circuit for introducing a voltage signal to be applied to the EA modulator in the reverse direction integrates each circuit element on a substrate using microwave integrated circuit technology in order to drive the EA modulator at high speed. EA modulator module.

FIG. 9 shows an example of the electrical configuration of a conventional EA modulator module. In FIG. 9, the EA modulator module 50 includes an EA modulator 51, a load resistance element 52 of 50Ω connected in parallel to the EA modulator 51, and an EA modulator 5.
Strip line 53 having one end connected to one voltage application end
, A driving circuit 54, and an inductance element 55 for connecting the output terminal of the driving circuit 54 and the other end of the strip line 53.
And

The EA modulator 51 has a continuously oscillating L
Continuous light from D61 is introduced via an optical transmission line 62. In the EA modulator module 50, the driving circuit 54
A voltage signal for driving the A modulator 51 is output. The output of the drive circuit 54 is applied to the EA modulator 51 through the inductance element 55 and the strip line 53, and the operation of changing the absorption coefficient of the EA modulator 51 is performed. As a result, the EA modulator 51 performs an operation of intensity-modulating the continuous light from the LD 61, and outputs an intensity-modulated optical signal from the optical transmission line 63.

FIG. 10 is a diagram for explaining characteristics when the load resistance of the EA modulator is viewed from the driving side of the EA modulator module shown in FIG. FIG. 10A shows the reflection coefficient S1.
FIG. 10B is an admittance chart showing the relationship between 1 and the input impedance Zin, and FIG.
FIG. 10C is a measurement circuit diagram.

As shown in FIG. 10C, since the inductance element 55 is a wire, its inductance component is connected in series to the strip line. Wire inductance increases with increasing frequency. On the other hand, the capacitance component of the EA modulator 51 decreases as the frequency increases.

In FIG. 10A, the measurement frequency range is from 100.0 kHz to 100.0 GHz. The frequency at the mark point m1 is 31.82 GHz, the reflection coefficient S (1,1) is 0.578 / 103.644, and the impedance is Z0 (0.413 + j0.700). In FIG. 10B, the horizontal axis is frequency (GHz),
The vertical axis is the reflection coefficient (dB). The frequency at the mark point m2 is 29.99 GHz, and the reflection coefficient dB ｛S
(1,1)｝ is −0.290 dB.

[0010]

However, in the conventional EA modulator module, when the EA modulator 51 is viewed from the drive circuit 54 side by the capacitance component of the EA modulator 51 and the inductance component of the inductance element 55. There is a problem that the impedance cannot be matched to 50Ω at high frequencies, the reflection characteristics (frequency characteristics of the reflection coefficient S11) deteriorate, and multiple reflection occurs between the drive circuit 54 and the EA modulator 51.

In the conventional EA modulator module,
Since the capacitance component of the EA modulator 51 and the load resistance element 52 are connected in parallel, there is also a problem that the forward transfer characteristics at high frequencies (frequency characteristics of the forward transfer coefficient S21) deteriorate.

The present invention has been made in view of the above, and has an EA modulator module having a configuration for compensating for characteristic deterioration due to an inductance component of an inductance element connecting a drive circuit and a strip line and a capacitance component of an EA modulator. The purpose is to obtain.

[0013]

In order to achieve the above object, an EA modulator module according to the present invention is an EA modulator which is a semiconductor element whose absorption coefficient changes according to an applied electric field and which intensity-modulates an optical signal. A modulator; a first inductance element having one end connected to a voltage application end of the EA modulator; a 50Ω load resistance element connected between the other end of the first inductance element and ground; A strip line having one end connected to a voltage application end of the modulator, a capacitive element connected between the other end of the strip line and ground, and a drive circuit for outputting a voltage signal for driving the EA modulator. And a second inductance element for connecting the output terminal of the drive circuit and the other end of the strip line.

According to the present invention, the characteristic that the impedance of the second inductance element increases at a high frequency is complemented by the complementary characteristic that the impedance of the capacitance element connected near the connection point between the second inductance element and the strip line decreases. It is compensated and the reflection characteristics are improved. Further, the characteristic that the impedance due to the capacitance component of the EA modulator decreases at a high frequency is compensated by the complementary characteristic that the impedance of the first inductance element connected between the EA modulator and the 50Ω load resistance element increases. , The forward transfer characteristics are improved.

The EA modulator module according to the next invention is an EA modulator which is a semiconductor element whose absorption coefficient changes in accordance with an applied electric field and which modulates the intensity of an optical signal.
A load resistance element having a resistance value smaller than 50Ω is connected in parallel with the A modulator, a strip line having one end connected to a voltage application terminal of the EA modulator, and a voltage signal for driving the EA modulator. A driving circuit for outputting the driving signal; and an inductance element for connecting an output terminal of the driving circuit and the other end of the strip line.

According to the present invention, the inductance element and the load resistance element are connected in series. However, since the load resistance element has a resistance value smaller than 50Ω, the combined impedance at a high frequency is equal to the inductance. By increasing the impedance of the element, it becomes closer to 50Ω and matching can be achieved, and the reflection characteristics are improved.

An EA modulator module according to the next invention is an EA modulator which is a semiconductor element whose absorption coefficient changes in accordance with an applied electric field and which modulates the intensity of an optical signal.
A load resistance element having a resistance value of 50Ω connected in parallel to the modulator, a combined circuit including a resistance element and a capacitance element connected in parallel with the load resistance element, and one end connected to a voltage application terminal of the EA modulator. A strip line to be connected;
A drive circuit for outputting a voltage signal for driving the A modulator, and an inductance element for connecting an output terminal of the drive circuit and the other end of the strip line are provided.

According to the present invention, when the impedance of the inductance element is to be increased at a high frequency, the combined impedance of the combined circuit is reduced, so that a compensation operation for suppressing the increase is performed, and the reflection characteristic is improved. On the other hand, at low frequencies, the combined impedance of the combining circuit becomes infinite, and the influence of the impedance of the inductance element is eliminated.

The EA modulator module according to the next invention is characterized in that the driving circuit is constituted by a distributed amplifier.

According to the present invention, the impedance when the load resistance element of the EA modulator is viewed from the drive circuit is matched to 50Ω. On the other hand, the impedance of the distributed amplifier which is the driving circuit from the load resistance element of the EA modulator can be matched to 50Ω up to high frequencies by adjusting the impedance of the line connecting each amplifier in the distributed amplifier.

An EA modulator module according to the next invention is characterized in that the first inductance element is constituted by a strip line.

According to the present invention, the inductance component of the first inductance element connected between the EA modulator and the 50 Ω load resistance element is accurately controlled by adjusting the width of the strip line and the width of the substrate. .

An EA modulator module according to the next invention is characterized in that the first inductance element is constituted by a coplanar line.

According to the present invention, the inductance component of the first inductance element connected between the EA modulator and the load resistance element of 50Ω adjusts the line width of the coplanar line and the distance between the line and the ground. Is controlled with high accuracy.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an EA modulator module according to the present invention will be described below in detail with reference to the accompanying drawings.

Embodiment 1 FIG. 1 is a diagram showing an electrical configuration of an EA modulator module according to Embodiment 1 of the present invention. FIG. 2 is a diagram illustrating characteristics when the load resistance of the EA modulator is viewed from the driving side of the EA modulator module shown in FIG. FIG. 3 is a diagram illustrating a frequency characteristic of the forward transfer coefficient S21 viewed from the voltage application end of the EA modulator illustrated in FIG.

In FIG. 1, an EA modulator module 10
Is an EA modulator 11 which is a semiconductor element whose absorption coefficient changes according to an applied electric field and which intensity-modulates an optical signal;
An inductance element 12 having one end connected to the voltage application end of the A modulator 11, a 50Ω load resistance element 13 connected between the other end of the inductance element 12 and the ground,
A strip line 14 having one end connected to the voltage application end of the EA modulator 11, a capacitive element 15 connected between the other end of the strip line 14 and the ground, and a voltage signal for driving the EA modulator 11 are output. Driving circuit 16 and driving circuit 1
6 and a wire 17 as an inductance element connecting the output end of the strip line 14 and the other end of the strip line 14.

In the above configuration, continuous light from the LD 21 oscillating continuously is introduced into the EA modulator 11 via the optical transmission line 22. In the EA modulator module 10, the drive circuit 16 outputs a voltage signal for driving the EA modulator 11. The output of the drive circuit 16 is applied to the EA modulator 11 through the wire 17 and the strip line 14,
An operation of changing the absorption coefficient of the EA modulator 11 is performed. As a result, the EA modulator 11 performs an operation of intensity-modulating the continuous light from the LD 21, and outputs an intensity-modulated optical signal from the optical transmission line 23.

Here, since the impedance (wire inductance component) of the wire 17 can be expressed as jωL, it increases as the frequency increases. On the other hand, the impedance (capacitance component) of the capacitive element 15 connected near the connection point between the wire 17 and the strip line 14 is 1 / (jωC)
Therefore, it decreases as the frequency increases. Therefore, the influence of the wire inductance component of the wire 17 is compensated for by the complementary characteristic that the capacitance component of the capacitive element 15 decreases, so that when the load resistance element 13 of the EA modulator 11 is viewed from the output of the drive circuit 16. The impedance is matched to 50Ω up to high frequencies, and the reflection characteristics (frequency characteristics of the reflection coefficient S11) are improved.

The capacitance component (capacitance) of the EA modulator 11 decreases as the frequency increases. On the other hand, E
An inductance element 12 provided between an A modulator 11 and a load resistance element 13 of 50Ω arranged in parallel with the A modulator 11.
Increase with increasing frequency. Therefore, the influence of the capacitance component (capacitance) of the EA modulator 11 is compensated by the complementary characteristic that the impedance of the inductance element 12 increases.
The forward transfer characteristic at a high frequency (the frequency characteristic of the forward transfer coefficient S21) is improved.

Hereinafter, the degree of improvement will be specifically described with reference to FIGS. 2A is an admittance chart showing a relationship between the reflection coefficient S11 and the input impedance Zin, and FIG. 2B is a diagram showing a frequency characteristic of the reflection coefficient S11, and FIG. ) Is a measurement circuit diagram.

As shown in FIG. 2C, a wire inductance compensating capacitance is connected between the connection point of the wire inductance component and the strip line and the ground. In addition, the EA modulator and 5 arranged in parallel with it.
An inductance component for compensating a capacitance component (capacitance) of the EA modulator is provided between the load resistance and the load resistance of 0Ω.

In FIG. 2A, the measurement frequency range is
It is from 100.0 kHz to 100.0 GHz. The frequency at the mark point m1 is 39.81 GHz, the reflection coefficient S (1,1) is 0.405 / 104.024, and the impedance is Z0 (0.614 + j0.578).
In FIG. 2B, the horizontal axis represents frequency (GHz), and the vertical axis represents reflection coefficient (dB). The frequency at the mark point m2 is 2.578 GHz, and the reflection coefficient dB ｛S (1,
1)｝ is -27.935 dB.

FIG. 10A without compensation and FIG. 2 with compensation
As can be understood from the comparison of the admittance chart with (a), the reflection coefficient S11 has an amplitude of 0.578 to 0.5.
405 and the reflection characteristic (reflection coefficient S of the S parameter)
11 is improved. Further, in the frequency characteristic, in the case of FIG. 10B, it can cover only up to about 55 GHz, but in the case of FIG.
It is shown that the frequency characteristic has been extended to about 2 GHz, which indicates that the frequency characteristic has been greatly improved.

In FIG. 3, the characteristic (1) is a forward transfer coefficient S2 when the inductance element 12 for compensating the impedance characteristic of the capacitance component of the EA modulator 11 exists.
1 is the frequency characteristic. The characteristic (2) is that the EA modulator 11
FIG. 11 is a frequency characteristic of the forward transfer coefficient S21 in the case shown in FIG. 9 where the impedance characteristic of the capacitance component of FIG. 9 is not compensated. From FIG. 3, it can be seen that it is improved in a high frequency region exceeding 30 GHz. This is because peaking occurs around 40 GHz due to the addition of an inductance component for compensation.

Embodiment 2 FIG. 4 is a diagram showing an electrical configuration of an EA modulator module according to Embodiment 2 of the present invention. In FIG. 4, the same reference numerals are given to the same elements as the circuit elements shown in FIG. Here, a description will be given focusing on a portion relating to the second embodiment.
This is the same in the following embodiments.

As shown in FIG. 4, in the second embodiment, the capacitive element 15 is omitted in FIG. 1, and the inductance element 12 for compensating the capacitive component of the EA modulator 11 is omitted. Load resistance elements 18 are connected in parallel. The load resistance element 18 has a resistance value smaller than 50Ω.

In the above configuration, the wire 17 is connected to the EA
It is connected in series to the load resistance element 18 of the modulator 11. The inductance component of the wire 17 increases at high frequencies. On the other hand, the impedance due to the capacitance component of the EA modulator 11 decreases at high frequencies. Therefore, the driving circuit 16
When the load resistance element 18 of the EA modulator 11 is viewed from the output of the EA modulator 11, the impedance is greatly affected by the inductance component of the wire 17 and becomes higher at higher frequencies, and the frequency characteristics of the reflection coefficient S11 at high frequencies deteriorate.

However, in the second embodiment, the load resistance element 18 of the EA modulator 11 has a resistance value smaller than 50Ω. Therefore, the combined impedance of the series circuit of the wire 17 and the load resistance element 18 approaches 50Ω at a high frequency, and EA from the output of the drive circuit 16
When the load resistance element 18 of the modulator 11 is viewed, the impedance can be matched to 50Ω. That is, the frequency characteristics of the reflection coefficient S11 at high frequencies are improved. Of course, the frequency characteristics of the reflection coefficient S11 at low frequencies are good. Therefore, the frequency characteristics are improved.

Embodiment 3 FIG. 5 is a diagram showing an electrical configuration of an EA modulator module according to Embodiment 3 of the present invention. As shown in FIG. 5, in the third embodiment,
In FIG. 1, the capacitive element 15 is omitted, and the EA modulator 1
A load resistance element 13 is connected in parallel to the EA modulator 11 by omitting the inductance element 12 for compensating the capacitance component of 1, and a combined circuit 19 of a resistance element and a capacitance element is connected in parallel to the load resistance element 13. ing.

In the above configuration, the combining circuit 19
At low frequencies, the impedance becomes ∞.
And the influence of the inductance component of the second embodiment is eliminated. Therefore,
From the output of the drive circuit 16, the value of 50Ω
Appears as the impedance value as it is. On the other hand, at higher frequencies, the impedance increases due to the influence of the inductance component of the wire 17, but the complementary characteristics of the impedance of the combining circuit 19 decrease, so that the characteristics cancel each other out and 50Ω matching can be obtained. for that reason,
Good frequency characteristics of the reflection coefficient S11 are obtained from low frequencies to high frequencies.

Embodiment 4 FIG. 6 is a diagram showing an electrical configuration of an EA modulator module according to Embodiment 4 of the present invention. As shown in FIG. 6, in the fourth embodiment,
In FIG. 1, a distributed amplifier 20 is provided in place of the drive circuit 16. A load resistance element of 50Ω is connected to a line to which each amplifier of the distributed amplifier 20 is connected.

In the configuration shown in FIG. 1, even when a good 50Ω matching is obtained from the output of the drive circuit 16 to the high frequency of the load resistance element 13 of the EA modulator 11 up to a high frequency, the output of the drive circuit 16 If the impedance looking at the drive circuit 16 is not 50Ω matching up to the high frequency,
Multiple reflection occurs between the drive circuit 16 and the EA modulator 11.

However, in the distributed amplifier 20, a good frequency characteristic of the reflection coefficient S22 up to a high frequency can be obtained by adjusting the impedance of the line connecting each amplifier. In the fourth embodiment, the distributed amplifier 20 includes the capacitive element 15 for compensating the inductance component of the wire 17.
And the inductance element 12 for compensating for the capacitance component of the EA modulator 11, the 50 Ω of the distributed amplifier 20 is added.
The area from the load resistance element to the 50Ω load resistance element 13 of the EA modulator 11 can be made to look like a strip line in a pseudo manner. Therefore, the voltage waveform applied to the EA modulator 11 has the same favorable waveform as when the output of the distributed amplifier 20 is viewed from the 50Ω load resistance element of the distributed amplifier 20.

Embodiment 5 FIG. The EA modulator module according to the fifth embodiment is different from the EA modulator module shown in FIG. 1 in that the EA modulator 11 and the load resistor 13
The inductance element 12 connecting between the two is formed of a strip line.

FIG. 7 shows a fifth embodiment E of the present invention.
It is a figure which shows the strip line used as an inductance element which compensates for the capacitance component of an EA modulator in an A modulator module. FIG. 7A is a mounting diagram, and FIG.
(B) is an equivalent circuit.

In FIG. 7, a strip line 31 used as the inductance element 12 has one end connected to the EA modulator 11 by a flip chip 32, and the other end formed with a load resistance element 13 of 50Ω. Note that one end of the strip line 14 is also connected to the EA modulator 11 by the flip chip 33.

The strip line 31 can have an arbitrary inductance component and an arbitrary capacitance component by changing the substrate width and the line width. In the fifth embodiment, the strip line 31 has a large substrate width and a narrow line width to provide an inductance component for compensating for the capacitance component of the EA modulator 11.

Embodiment 6 FIG. The EA modulator module according to the sixth embodiment is different from the EA modulator module shown in FIG. 1 in that the EA modulator 11 and the load resistance element 13
The inductance element 12 connecting between the two is constituted by a coplanar line.

FIG. 8 shows a sixth embodiment of the present invention.
It is a figure which shows the coplanar line used as an inductance element which compensates the capacitance component of an EA modulator in an A modulator module. FIG. 8A is a mounting diagram, and FIG.
(B) is an equivalent circuit.

In FIG. 8, one end of a coplanar line 41 used as the inductance element 12 is connected to the EA modulator 11 by a flip chip 42, and
Line 41a on which 0 Ω load resistance element 13 is formed
And a ground 41b arranged on both sides of the line 41a. Note that one end of the strip line 14 is similarly connected to the EA modulator 11 by the flip chip 42.

The coplanar line 41 can have any inductance and capacitance components by adjusting the distance between the line 41a and the ground 41b and the line width. In the sixth embodiment, the line width of the coplanar line 41 is reduced, and the distance between the line 41a and the ground 41b is increased to provide an inductance component for compensating the capacitance component of the EA modulator 11.

[0053]

As described above, according to the present invention, the characteristic that the impedance of the second inductance element increases at a high frequency depends on the impedance of the capacitance element connected near the connection point between the second inductance element and the strip line. This is compensated by the complementary characteristic of decreasing, and the reflection characteristic is improved. The characteristic that the impedance due to the capacitance component of the EA modulator decreases at high frequencies is different from that of the EA modulator.
The compensation is made by the complementary characteristic that the impedance of the first inductance element connected to the load resistor of 0Ω is increased, so that the forward transfer characteristic is improved.
Therefore, good matching characteristics can be obtained up to high frequencies, and the frequency characteristics can be improved.

According to the next invention, since the resistance value of the load resistance element is smaller than 50Ω, the combined impedance with the inductance element approaches 50Ω by increasing the impedance of the inductance element at a high frequency so that matching can be achieved. And the reflection characteristics are improved.
Therefore, good matching characteristics can be obtained, and the frequency characteristics can be improved.

According to the next invention, the characteristic that the impedance of the inductance element increases at high frequencies is compensated by the characteristic that the combined impedance of the combining circuit decreases, so that the reflection characteristic is improved. Therefore, good matching characteristics can be obtained up to high frequencies, and the frequency characteristics can be improved.

According to the present invention, the impedance when the load resistance element of the EA modulator is viewed from the drive circuit is matched to 50 Ω, and in addition, the distributed amplifier which is the drive circuit is changed from the load resistance element of the EA modulator. The impedance that saw
Since it is possible to match 50Ω up to a high frequency, it is possible to improve both the reflection characteristics and the forward transmission characteristics, thereby improving the frequency characteristics.

According to the next invention, the EA modulator and the 50 Ω
Since the first inductance element connecting between the load resistance elements is constituted by a strip line, the inductance component can be accurately controlled by adjusting the line width and the board width, and a good forward transfer characteristic is obtained. Will be obtained.

According to the next invention, the EA modulator and the 50 Ω
Since the first inductance element connecting between the load resistance elements is constituted by a coplanar line, the inductance component can be accurately controlled by adjusting the line width and the distance between the line and the ground. A good forward transmission characteristic can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an electrical configuration of an EA modulator module according to Embodiment 1 of the present invention.

FIG. 2 is a diagram illustrating characteristics when a load resistance of the EA modulator is viewed from a driving side of the EA modulator module illustrated in FIG. 1; 2A is an admittance chart showing a relationship between the reflection coefficient S11 and the input impedance Zin, FIG. 2B is a diagram showing a frequency characteristic of the reflection coefficient S11, and FIG. 2C is a measurement circuit diagram. is there.

FIG. 3 is a diagram illustrating a frequency characteristic of a forward transfer coefficient S21 viewed from a voltage application end of the EA modulator illustrated in FIG. 1;

FIG. 4 is a diagram illustrating an electrical configuration of an EA modulator module according to Embodiment 2 of the present invention;

FIG. 5 is a diagram showing an electrical configuration of an EA modulator module according to Embodiment 3 of the present invention.

FIG. 6 is a diagram showing an electrical configuration of an EA modulator module according to Embodiment 4 of the present invention.

FIG. 7 is a diagram showing a strip line used as an inductance element for compensating a capacitance component of the EA modulator in the EA modulator module according to the fifth embodiment of the present invention. FIG. 7A is a mounting diagram, and FIG. 7B is an equivalent circuit.

FIG. 8 is a diagram showing a coplanar line used as an inductance element for compensating a capacitance component of the EA modulator in the EA modulator module according to the sixth embodiment of the present invention. FIG. 8A is a mounting diagram, and FIG. 8B is an equivalent circuit.

FIG. 9 is a diagram showing an electrical configuration of a conventional EA modulator module.

FIG. 10 is a diagram illustrating characteristics when the load resistance of the EA modulator is viewed from the drive side of the EA modulator module illustrated in FIG. 9; 10A is an admittance chart showing a relationship between the reflection coefficient S11 and the input impedance Zin, FIG. 10B is a diagram showing a frequency characteristic of the reflection coefficient S11, and FIG. 10C is a measurement circuit diagram. is there.

[Explanation of symbols]

10 EA modulator module, 11 EA modulator, 12
An inductance element, a 1350Ω load resistance element,
14 strip line, 15 capacitance element, 16 drive circuit, 17 wires, load resistance element having a value smaller than 1850Ω, 19 composite circuit of resistance element and capacitance element, 20
Distributed amplifier, 21 laser diode, 22, 23 optical transmission line, 31 strip line, 32, 33, 42, 4
3 Flip chip, 41 coplanar line, 41a line, 41b ground.

Claims (6)

[Claims] 1. An EA modulator, which is a semiconductor element whose absorption coefficient changes according to an applied electric field to modulate the intensity of an optical signal, and a first inductance having one end connected to a voltage application terminal of the EA modulator. An element, a 50 Ω load resistance element connected between the other end of the first inductance element and ground, a strip line having one end connected to a voltage application end of the EA modulator, A capacitive element connected between one end and ground, a drive circuit for outputting a voltage signal for driving the EA modulator, and a second inductance for connecting an output end of the drive circuit to the other end of the strip line. An EA modulator module, comprising: an element; 2. An EA modulator, which is a semiconductor element whose intensity changes an absorption coefficient according to an applied electric field to modulate the intensity of an optical signal, and a resistance value smaller than 50Ω connected in parallel to the EA modulator. A load resistor element, a strip line having one end connected to a voltage application terminal of the EA modulator, a drive circuit for outputting a voltage signal for driving the EA modulator, an output terminal of the drive circuit, and the strip line An EA modulator module, comprising: an inductance element connected to the other end of the EA modulator. 3. An EA modulator, which is a semiconductor element whose intensity changes an absorption coefficient according to an applied electric field and modulates an intensity of an optical signal, and a load having a resistance value of 50Ω connected in parallel to the EA modulator. A resistance element, a synthesis circuit including a resistance element and a capacitance element connected in parallel with the load resistance element, a strip line having one end connected to a voltage application terminal of the EA modulator, and a voltage for driving the EA modulator. An EA modulator module, comprising: a drive circuit that outputs a signal; and an inductance element that connects an output terminal of the drive circuit and the other end of the strip line. 4. The EA modulator module according to claim 1, wherein said drive circuit is constituted by a distributed amplifier. 5. The EA modulator module according to claim 1, wherein the first inductance element is constituted by a strip line. 6. The EA modulator module according to claim 1, wherein the first inductance element is constituted by a coplanar line.