JPH1075003A - Semiconductor laser module with built-in matching unit - Google Patents

Abstract

(57) Abstract: A semiconductor laser module for directly inputting a microwave frequency signal as a modulation signal to obtain high modulation efficiency and stable characteristics in a desired frequency band. An input impedance matching circuit unit for connecting between a laser diode chip and a modulation signal input terminal is provided inside a module package.
The input impedance matching circuit unit 8 has a structure in which components such as a microstrip line, a reactance element, and a bonding wire are integrated on a single dielectric substrate. As a result, the transmission efficiency of the modulation signal is improved in a desired frequency band, a high degree of modulation is obtained with a small power signal, and the transmission efficiency and the stability of matching characteristics such as a matching frequency band are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser module used in an optical communication system using a direct modulation method.

[0002]

2. Description of the Related Art In recent years, semiconductor laser modules have been
Applications to communication fields that handle signals in the microwave frequency range, such as TV and public communication, have been actively attempted, and practical use has begun. Among them, in short-to-middle distance transmission of several hundreds of meters to several kilometers, in which accumulation of noise and signal distortion is small, a direct intensity modulation method of converting a high-frequency signal into an optical signal as a direct modulation signal is a simple and cost-effective facility. Effective in terms of surface.

[0003] In the equivalent circuit of the conventional semiconductor laser module shown in FIG.
2 is a laser diode chip, 13 is a transmission line inside the module package, 14 is a DC bias circuit, 15 is a modulation signal input terminal, 16 is a transmission line having a specified characteristic impedance, and 17 is an input impedance matching resistor.

The operation of this semiconductor laser module is performed as follows. First, the DC bias circuit 14
A drive current is supplied to excite and oscillate the laser diode chip 12. Next, a high-frequency modulation signal is input from the modulation signal input terminal 15 to directly modulate the laser diode chip 12. Normally, the load of the laser diode chip is several Ω, and the characteristic impedance of the transmission line 7 is 50 Ω.
Therefore, the matching with the characteristic impedance of the transmission line 16 is realized by inserting the input impedance matching resistor 17.

[0005] In another conventional example shown in FIG. 3, a signal input circuit outside the package module 11 has an LC input circuit.
By inserting the type impedance matching circuit 19 and appropriately setting the LC circuit constant, matching between the characteristic impedance of the transmission line 16 in the desired frequency band and the input impedance of the semiconductor laser module is realized.

[0006]

However, in the above-mentioned first conventional structure, the load resistance inserted in series becomes several times larger than the load of several Ω of the laser diode, so that the power of the modulation signal power is increased. Most is consumed by the load resistance. For this reason, the input power efficiency converted by the laser diode chip 12 decreases, and the degree of modulation decreases.

For example, when the load of the laser diode chip is 3Ω and the load resistance is 39Ω, the impedance matching is represented by a voltage standing wave VSWR as shown in FIG. FIG. 5 shows a graph in which the light modulation level at this time is represented by the ratio S21 between the light modulation output power and the modulation signal input current.
As can be seen from FIG. 4, the insertion of the load resistor 17 for input impedance matching lowers the VSWR.
Matching has been achieved. However, as can be seen from FIG. 5, since the power consumed by the resistor is large, the modulation signal power and the output level that can be converted by the laser diode chip are low. Therefore, in order to obtain a desired degree of modulation, it is necessary to input a large modulation signal power. As a result, it is necessary to newly provide a pre-amplifier or to increase the gain of an existing pre-amplifier. It becomes a factor of increase in size, size, and cost. Also, with the increase in the output of the amplifier,
Mutual distortion also increases.

In the second conventional configuration, the transmission line 13 inside the module package connecting the laser diode chip 12 and the modulation signal input terminal 15 is constituted by a microstrip line, a bonding wire, etc., and functions as an inductance component. For this reason, the frequency range in which matching can be performed by the LC impedance matching circuit 18 outside the module package is limited. FIG. 6 is a graph of a frequency characteristic in which impedance matching is represented by a voltage standing wave ratio VSWR. FIG. 7 is a graph of a frequency characteristic in which an optical modulation level at this time is represented by a ratio S21 between an optical modulation output power and a modulation signal input current. It is a graph. Input impedance matching circuit 18
It can be seen from FIGS. 6 and 7 that the VSWR is reduced and that the modulation signal power that can be converted by the laser diode 12 is large, so that a high optical output level can be realized at a frequency of 600 MHz. However, since the transmission line 13 inside the module package has an electrical length that functions as an inductance component, input impedance matching in a desired frequency band, for example, 1200 MHz cannot be realized due to these effects.

[0009] Further, it is necessary to transmit signals in a plurality of bands when transmitting wireless signals optically. In this case, it becomes more difficult to match the input impedance and efficiently drive the laser module by modulation.

Also, an LC composed of several circuit elements
A space for mounting the mold input impedance matching circuit 19 outside the module package must be secured, which causes an increase in the size of the device.

Further, the LC outside the module package
Regarding the type impedance matching circuit 19, variations in circuit constants occur due to differences in the mounting state of the material of the printed circuit board to be mounted, the transmission path, the matching circuit element, the module, and the circuit element, thereby lowering the conversion efficiency, shifting the matching frequency band, and the like. Causes the characteristic deterioration. For this reason, the characteristics of the desired frequency cannot be compensated for by the semiconductor laser module device alone, and it is necessary to inspect and adjust the input impedance matching state. This causes an increase in cost and a decrease in yield.

SUMMARY OF THE INVENTION The present invention has been made to solve the conventional problems as described above, and realizes input impedance matching in a single or a plurality of frequency bands, and can obtain a high modulation degree with a small modulation signal power. It is an object of the present invention to provide a semiconductor laser module having a built-in matching circuit unit requiring no adjustment.

[0013]

In order to achieve this object, a semiconductor laser module with a built-in matching unit according to the present invention includes a module package containing a laser diode chip and having a modulation signal input terminal.
An impedance matching circuit unit that connects the laser diode chip and the modulation signal input terminal, the impedance matching circuit unit is configured by arranging a metal transmission line and a matching circuit element on a single dielectric substrate, It has one or more frequency bands.

[0014] Preferably, the input impedance matching circuit unit includes a microstrip line having a predetermined characteristic impedance, a bonding wire, and a reactance element as constituent elements. It is also preferable that the input impedance matching circuit unit includes an inductance element connected in series with the microstrip line, and a capacitance element connected between the microstrip line and the ground side of the laser diode.

It is preferable that the input impedance matching circuit unit includes a resistance element as a component in addition to the reactance element, and the resistance element is connected in series to the laser diode chip. As a result, changes in the matching state and the drive current can be suppressed. However, from the viewpoint of suppressing the insertion loss, the resistance value of the resistance element is desirably 10Ω or less. further,
Preferably, the resistance element is connected between the reactance element and the laser diode chip.

The circuit constant of the input impedance matching circuit unit is not limited to a single frequency band, and may be set so that transmission efficiency is improved simultaneously in a plurality of frequency bands. It is also preferable that a bias circuit and a bias input terminal for driving the laser diode chip be provided in the input impedance matching circuit unit and housed inside the module package.

Also, a first input impedance matching circuit unit for improving transmission efficiency in a first frequency band and a second input impedance matching circuit unit for improving transmission efficiency in a second frequency band are provided. It is preferable that the frequency characteristics be switched by selectively using the first and second input impedance matching circuit units. In this case, the first and second
May be configured so that transmission efficiency is improved in a plurality of frequency bands. Further, a configuration in which the frequency characteristics are switched by selectively using three or more input impedance matching circuit units having good transmission efficiency in each frequency band for three or more frequency bands is also preferable.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. 1 shows the internal structure of a semiconductor laser module according to an embodiment of the present invention. In FIG. 1, 1 is a module package, 2 is a laser diode chip,
Reference numeral 3 denotes an optical fiber, 4 denotes a chip carrier, 5 denotes a lead pin serving as a modulation signal input terminal and a bias input terminal, 6 denotes a lens, and 8 denotes an input impedance matching circuit unit. The input impedance matching circuit unit 8 is inserted between the laser diode 2 and the lead pin 5 and connects them.

FIG. 8 shows an equivalent circuit of the semiconductor laser module of this embodiment. 8, the same circuit elements as those in FIG. 2 used for describing the conventional example are denoted by the same reference numerals. FIG. 8 differs from FIG. 2 in the following points. That is,
The transmission line 13 inside the module package is replaced with an input impedance matching circuit unit 18 without adding the input impedance matching resistor 17. The input impedance matching circuit unit 18 includes a bonding wire 181, an inductance element 182 that is a reactance element inserted in series, and a microstrip line 18.
3. Consisting of capacitance elements 184 and 185, which are reactance elements inserted in parallel.

The operation of this semiconductor laser module is as follows. When a DC drive current is supplied from the DC bias circuit 14, the laser diode chip 12 is excited and oscillates. Then, by inputting a high-frequency modulation signal from the modulation signal input terminal 15, the laser diode chip 12 can be directly modulated. The input impedance matching circuit unit 18 performs the function of impedance matching between the load of several Ω of the laser diode chip 12 and the characteristic impedance of 50 Ω of the transmission line 16. That is, the characteristic impedance of the transmission line 16 and the load impedance of the laser diode chip 12 in a desired frequency band can be matched by appropriately setting the constants of the elements constituting the input impedance matching circuit 18.

As a specific example, the bonding wire 18
1. Examples of matching input impedance at 1200 MHz by adjusting circuit constants of inductance element 182, microstrip line 183, and capacitance elements 184 and 185 are shown in FIGS.
0 is shown. FIG. 9 is a graph showing the input impedance matching by the voltage standing wave ratio VSWR, and FIG. 10 is a graph showing the optical modulation level at that time by the ratio S21 between the optical modulation output power and the modulation signal input current. As can be seen from these graphs, at a desired frequency of 1200 MHz, V
The SWR was smaller than about 1.2, the optical modulation output was also at a high level, and the modulation signal converted by the laser diode could be increased as compared with the conventional example of FIG.

As described above, according to the present embodiment, by providing the input impedance matching circuit unit 18 inside the module package 11, the impedance is matched in a desired frequency band, and even if the signal is a low power modulated signal. Thus, a semiconductor laser module capable of obtaining a high light modulation level and a high degree of modulation can be realized.
Further, since the input impedance matching circuit unit 18 exists inside the module package 11, stable matching characteristics can be realized. Therefore, as compared with an external matching circuit in which variations in characteristics are likely to occur, the probability of occurrence of characteristic deterioration such as a decrease in conversion efficiency and a shift in the matching frequency band is reduced. Further, since the characteristics of the desired frequency can be obtained by the semiconductor laser module alone, the steps of inspecting and adjusting the input impedance become unnecessary. As a result, cost reduction and improvement in yield are realized.

The input impedance matching circuit unit 18 provided inside the module package 11 includes a bonding wire 181, an inductance element 182,
Various modifications are possible without being limited to the above-described configuration using the microstrip line 183 and the capacitance elements 184 and 185.

(Embodiment 2) Next, Embodiment 2 of the present invention
FIG. 11 shows an equivalent circuit of the semiconductor laser module according to FIG. This circuit differs from FIG. 8 of the first embodiment in that a resistance element (hereinafter referred to as “load resistance”) 186 is inserted in series between the bonding wire 181 and the laser diode chip 12. The load resistor 186 has a function of suppressing a change in a matching state due to a change in impedance of the laser diode chip 12 and a change in a driving current. That is, by setting the combined value of the impedance of the laser diode chip 12 and the load resistor 186 to a value larger than the impedance of the laser diode chip 12, the occurrence of impedance mismatch due to the fluctuation of the laser diode chip 12 is suppressed. You. Also,
An increase in the secondary or tertiary intermodulation distortion of the high frequency modulation signal is also suppressed. The value of the load resistor 186 is set to 10Ω or less, preferably 5Ω or less in order to prevent a decrease in conversion efficiency.

As described above, according to the semiconductor laser module of this embodiment, since the input impedance matching circuit unit 18 including the resistance element 186 connected in series with the laser diode 12 is provided inside the module package, Input impedance matching in the frequency band described above, a large degree of modulation can be obtained even with a low-power modulation signal, and the occurrence of impedance mismatch when the operating state changes is suppressed.

The position where the load resistor is inserted is not limited to the position between the bonding wire 181 and the laser diode chip 12, and may be arranged in series with the laser diode chip 12 regardless of the configuration of the input impedance matching circuit unit. Can be inserted at the position.

(Embodiment 3) Next, Embodiment 3 of the present invention.
Will be described. This embodiment corresponds to Embodiment 1 (FIG. 8) or Embodiment 2 (FIG. 1).
Input impedance matching circuit unit 18 shown in 1)
By properly selecting the constants of each element that constitutes
Impedance matching is performed in two frequency bands. That is, by adjusting at least one of the bonding wire 181, the inductance element 182, the microstrip line 183, and the capacitance elements 184 and 185, input impedance matching in two frequency bands is performed simultaneously.

As specific examples, 900 MHz and 1500 MHz
12 and 13 show examples in which input impedance matching is performed in two MHz bands. FIG. 12 is a graph showing the input impedance matching by the voltage standing wave ratio VSWR, and FIG. 13 is a graph showing the optical modulation level at that time by the ratio S21 between the optical modulation output power and the modulation signal input current. At 900 MHz, VSWR = 1.6, 1500 MH
At z, VSWR = 1.4 was obtained, and the optical output was simultaneously high in both frequency regions, and the modulation signal converted by the laser diode could be increased.

As described above, according to the present embodiment, the input impedance matching circuit unit 18 is provided inside the package of the semiconductor laser module, and at the same time, the input impedance matching is realized so that the transmission efficiency is improved in two frequency bands. . Note that input impedance matching can be realized in three or more frequency bands by adding an inductance element and a capacitance element.

(Embodiment 4) Next, FIG. 14 shows an equivalent circuit of a semiconductor laser module according to Embodiment 4 of the present invention. This circuit differs from FIG. 8 of the first embodiment in that the input impedance matching circuit unit 18 has
Microstrip line 183 and modulation signal input terminal 1
5 in that a bias circuit 24 is included. The bias circuit 24 includes a bias input terminal 241, a choke inductor 242 for blocking a high frequency modulation signal, and a DC cut capacitor 243. Since each of the choke inductor 242 and the DC cut capacitor 243 has a sufficiently large inductance or capacitance, it does not affect the matching state of the input impedance. Therefore, the characteristics of the configuration of FIG. 8 of the first embodiment, for example, the characteristics of FIGS. 9 and 10 do not change.

As described above, according to the present embodiment, the bias circuit 24 normally provided outside the module package 11 is housed inside the module package 11 and formed on the same substrate as the input impedance matching circuit unit. Thereby, further integration of the semiconductor laser module can be achieved.

The input impedance matching circuit unit is not limited to the configuration employed in the present embodiment, but may employ another configuration. In the present embodiment, the bias circuit 24 is provided between the microstrip line 183 and the modulation signal input terminal 15, but may be provided at another position, for example, between the bonding wire 181 and the laser diode chip 12. .

(Embodiment 5) Next, Embodiment 5 of the present invention
FIG. 15 shows an equivalent circuit of the semiconductor laser module according to the first embodiment. In this embodiment, as the input impedance matching circuit unit 18, a first input impedance matching circuit unit 28 or a second input impedance matching circuit unit 38 is selectively connected. The first and second input impedance matching circuit units 28 and 38 have different circuit constants, and are set so that transmission efficiency is good in different frequency bands. In other words, according to the frequency band to which the semiconductor laser module applies,
Switching of the matching frequency characteristic is performed by selectively using one of the first and second input impedance matching circuit units. All components other than the input impedance matching circuit unit are common.

As a specific example, the first desired frequency is 900 MHz, and the second desired frequency is 1900 MHz.
16 and 17 show examples in which the matching characteristics are switched in two frequency bands of z. FIG. 16 shows a 900M
9 is a graph showing an optical modulation level when matching at Hz is performed by a ratio S21 between an optical modulation output power and a modulation signal input current. FIG. 17 shows the optical modulation level when the first input impedance matching circuit unit 28 is replaced with the second input impedance matching circuit unit 38 and matching is performed at 1900 MHz.
21 is a graph represented by a ratio of 21.

As described above, according to the semiconductor laser module of the present embodiment, by selecting one of the two input impedance matching circuit units having good transmission efficiencies in different frequency bands, a desired one can be obtained. Matching in a frequency band can be performed. Switching of the matching frequency characteristic can be performed only by replacing the matching circuit unit while keeping the other components common.

The number of input impedance matching circuit units is not limited to two, and three or more frequency bands may be switched by selecting one from three or more.

(Embodiment 6) Next, Embodiment 6 of the present invention.
FIG. 18 shows an equivalent circuit of the semiconductor laser module according to the first embodiment. This embodiment differs from the configuration of the fifth embodiment shown in FIG. 15 in that the circuit constants of the first input impedance matching circuit unit 48 are set so that the transmission efficiency is simultaneously improved in two frequency bands. The point is that the circuit constant of the second input impedance matching circuit unit 58 is set such that the transmission efficiency is simultaneously improved in another two frequency bands.

As in the fifth embodiment, the frequency characteristics are switched so as to match the semiconductor laser module by replacing the first and second input impedance matching circuit units. Also in this case, all the components other than the input impedance matching circuit unit are common.

As a specific example, FIGS. 19 and 2 show an example in which matching frequency characteristics are switched in two bands of 900 MHz and 1500 MHz as the first desired frequency and 1900 MHz and 2400 MHz as the second desired frequency.
0 is shown. FIG. 20 shows 900 MHz and 1500 MHz using the first input impedance matching circuit unit 38.
5 is a graph showing the optical modulation level as a ratio S21 between the optical modulation output power and the modulation signal input current when performing the simultaneous matching of FIG. FIG. 20 shows that, from this configuration, the first input impedance matching circuit unit 28 is replaced with a second input impedance matching circuit unit 38 so that 1900 MHz and 240
It is the graph which expressed the optical modulation level at the time of performing the simultaneous matching of 0 MHz by the ratio S21 of an optical modulation output power and a modulation signal input current.

As described above, according to the semiconductor laser module of the present embodiment, even when an input impedance matching circuit unit having good transmission efficiency in two frequency bands is used at the same time, as in the fifth embodiment, two input sources are used. By selectively using the impedance matching circuit unit, a desired set of frequency bands can be matched. The switching of the matching frequency characteristic can be performed only by replacing the matching circuit unit while keeping the other components common.

The number of input impedance matching circuit units is not limited to two, and three or more frequency bands may be switched by selecting one from three or more.

[0042]

According to the semiconductor laser module of the present invention, an input impedance matching circuit unit for connecting between a laser diode chip and a modulation signal input terminal is provided inside a package to realize input impedance matching in a desired frequency band. In addition, a high degree of modulation can be obtained with a small amount of modulated signal power, and characteristic deterioration is reduced. Further, it is possible to flexibly respond to a frequency band switching request.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the internal structure of a semiconductor laser module according to an embodiment of the present invention.

FIG. 2 is an equivalent circuit diagram of the semiconductor laser module of Conventional Example 1.

FIG. 3 is an equivalent circuit diagram of a semiconductor laser module of Conventional Example 2.

FIG. 4 is a graph showing a relationship between an input modulation signal frequency and VSWR in the semiconductor laser module of Conventional Example 1;

FIG. 5 shows an input modulation signal frequency and an optical modulation output power / input signal current ratio S in the semiconductor laser module of Conventional Example 1.
Graph showing the relationship of 21

FIG. 6 is a graph showing the relationship between the input modulation signal frequency and the VSWR in the semiconductor laser module of Conventional Example 2;

FIG. 7 shows an input modulation signal frequency and an optical modulation output power / input signal current ratio S in the semiconductor laser module of Conventional Example 2.
Graph showing the relationship with 21

FIG. 8 is an equivalent circuit diagram of the semiconductor laser module according to the first embodiment of the present invention.

9 is a graph showing a relationship between an input modulation signal frequency and VSWR in the semiconductor laser module of FIG.

FIG. 10 shows an input modulation signal frequency and an optical modulation output power / input signal current ratio S2 in the semiconductor laser module of FIG. 8;
Graph showing the relationship with 1

FIG. 11 is an equivalent circuit diagram of a semiconductor laser module according to Embodiment 2 of the present invention.

FIG. 12 is a graph showing the relationship between the input modulation signal frequency and VSWR in the semiconductor laser module according to Embodiment 3 of the present invention.

FIG. 13 shows the relationship between the input modulation signal frequency and the optical modulation output power / in the semiconductor laser module according to Embodiment 3 of the present invention.
Graph showing the relationship of the input signal current ratio S21

FIG. 14 is an equivalent circuit diagram of a semiconductor laser module according to Embodiment 4 of the present invention.

FIG. 15 is an equivalent circuit diagram of a semiconductor laser module according to Embodiment 5 of the present invention.

16 is a graph showing a relationship between a first input modulation signal frequency and an optical modulation output power / input signal current ratio S21 in the semiconductor laser module of FIG.

17 is a graph showing a relationship between a second input modulation signal frequency and an optical modulation output power / input signal current ratio S21 in the semiconductor laser module of FIG.

FIG. 18 is an equivalent circuit diagram of a semiconductor laser module according to Embodiment 6 of the present invention.

FIG. 19 is a graph showing a relationship between a first input modulation signal frequency and an optical modulation output power / input signal current ratio S21 in the semiconductor laser module of FIG. 18;

20 is a graph showing a relationship between a second input modulation signal frequency and an optical modulation output power / input signal current ratio S21 in the semiconductor laser module of FIG. 18;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Module package 2 Laser diode chip 3 Optical fiber 4 Chip carrier 5 Lead pin 6 Lens 8 Input impedance matching circuit unit 11 Module package 12 Laser diode chip 13 Transmission path inside module package 14 Bias circuit 15 Modulation signal input terminal 16 Predetermined characteristic impedance Transmission line having: 17 input impedance matching resistor 18 input impedance matching circuit unit 181 bonding wire 182 inductance element 183 microstrip line 185, 186 capacitance element 19 LC type matching circuit outside module package 24 configured in input impedance matching circuit unit Bias circuit 241 bias input terminal 242 choke inductance element 2 43 Capacitance element for DC cut 28 Input impedance matching circuit unit for 900 MHz 38 Input impedance matching circuit unit for 1900 MHz 48 Input impedance matching circuit unit for 900 MHz and 1500 MHz 58 Input impedance matching circuit unit for 1900 MHz and 2400 MHz

Claims (11)

[Claims] An impedance matching circuit for connecting the laser diode chip to the modulation signal input terminal in a module package accommodating the laser diode chip and having a modulation signal input terminal; A semiconductor laser module with a built-in matching unit, wherein the unit is configured by arranging a metal transmission line and a matching circuit element on a single dielectric substrate, and has one or more frequency bands. 2. The semiconductor laser module with a built-in matching unit according to claim 1, wherein said input impedance matching circuit unit includes a microstrip line having a predetermined characteristic impedance, a bonding wire, and a reactance element as constituent elements. 3. The input impedance matching circuit unit includes an inductance element connected in series with the microstrip line, and a capacitance element connected between the microstrip line and a ground side of the laser diode. The semiconductor laser module with a built-in matching unit according to claim 2. 4. The input impedance matching circuit unit includes a resistance element as a constituent element and is connected in series with the laser diode chip.
4. A semiconductor laser module with a built-in matching unit according to 2 or 3. 5. The semiconductor laser module with a built-in matching unit according to claim 4, wherein the resistance value of said resistance element is 10Ω or less. 6. The semiconductor laser module with a built-in matching unit according to claim 4, wherein said resistance element is connected between said reactance element and said laser diode chip. 7. The semiconductor with a built-in matching unit according to claim 1, wherein circuit constants of said input impedance matching circuit unit are set so that transmission efficiency is improved simultaneously in a plurality of frequency bands. Laser module. 8. The semiconductor laser module with a built-in matching unit according to claim 1, wherein said input impedance matching circuit unit includes a bias circuit and a bias input terminal. 9. A first input impedance matching circuit unit for improving transmission efficiency in a first frequency band, and a second input impedance matching circuit unit for improving transmission efficiency in a second frequency band, The frequency characteristic is switched by selectively using the first and second input impedance matching circuit units.
9. The semiconductor laser module with a built-in matching unit according to any one of items 1 to 8. 10. A first input impedance matching circuit unit having good transmission efficiency in a first set of plural frequency bands, and a second input impedance matching circuit unit having good transmission efficiency in a second set of plural frequency bands. 9. The semiconductor with a built-in matching unit according to claim 1, further comprising a matching circuit unit, wherein the frequency characteristic is switched by selectively using the first and second input impedance matching circuit units. Laser module. 11. The frequency characteristic is switched by selectively using three or more input impedance matching circuit units having good transmission efficiency in each frequency band for three or more sets of frequency bands. 9. The semiconductor laser module with a built-in matching unit according to any one of 1 to 8.