Laser light source device

Abstract

The pins (2a, 2b) pass through the metal tube seat (1). The support block (3) is mounted on the metal tube seat (1). The dielectric substrate (4) is mounted on the side of the support block (3). The signal lines (5a, 5b) are formed on the dielectric substrate (4). One end of the signal lines (5a, 5b) is connected to the pins (2a, 2b). The semiconductor light modulator (6) is mounted on the dielectric substrate (4). The conductive wires (8a, 8b) connect the other end of the signal lines (5a, 5b) to the semiconductor light modulator (6). The semiconductor light modulator (6) has a plurality of light modulators (6b, 6c) separated from each other.

Description

Technical Field

[0001] The present disclosure relates to a laser light source device including a semiconductor light modulation element. Background Art

[0002] The spread of SNS and video sharing services is advancing globally, and the capacity of data transmission is accelerating. In response, the speed and size of optical transceivers are being improved to cope with the high-speed and high-capacity transmission of signals in limited installation space.

[0003] As an existing laser light source device equipped with a semiconductor light modulator, a device is disclosed in which pins passing through a metal stem and AC-GND are converted into coplanar lines and connected to a semiconductor light modulator mounted on a temperature control module (for example, refer to Patent Document 1).

[0004] Patent Document 1: Japanese Patent Application No. 2011-518381

[0005] In the existing laser light source device, a semiconductor light modulator having a single light modulator is used, and the electrical signal input method to the semiconductor light modulator is a single-layer drive method. If the length of the light modulator is shortened, broadband can be achieved. However, the shortening of the size is in a trade-off relationship with the extinction ratio. Therefore, if the size of the light modulator is shortened to achieve broadband, there is a problem that a sufficient extinction ratio cannot be ensured. Summary of the invention

[0006] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to obtain a laser light source device capable of achieving a wide bandwidth while ensuring a sufficient extinction ratio.

[0007] The laser light source device involved in the present disclosure is characterized in that it comprises: a metal tube seat; a pin that passes through the above-mentioned metal tube seat; a support block that is installed on the above-mentioned metal tube seat; a dielectric substrate that is installed on the side of the above-mentioned support block; a signal line formed on the above-mentioned dielectric substrate and connected to the above-mentioned pin at one end; a semiconductor light modulator element that is installed on the above-mentioned dielectric substrate; and a conductive wire that connects the other end of the above-mentioned signal line to the above-mentioned semiconductor light modulator element, and the above-mentioned semiconductor light modulator element has a plurality of light modulators separated from each other.

[0008] In the present disclosure, the semiconductor optical modulation element has a plurality of optical modulators separated from each other. As a result, the length of each optical modulator is shorter than before, so the electrostatic capacitance becomes smaller. Therefore, the gain relative to the frequency band is improved and a wide frequency band can be achieved. In addition, the extinction ratio equivalent to that of a conventional single optical modulator can be ensured by using a plurality of optical modulators. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a perspective view showing the laser light source device according to the first embodiment.

[0010] Figure 2 This is a plan view showing a light modulator section of the semiconductor light modulator element according to the first embodiment.

[0011] Figure 3 This is a diagram showing a circuit configuration of a laser light source device according to Embodiment 1.

[0012] Figure 4 This is a diagram showing the results of a three-dimensional electromagnetic field simulation of the frequency response characteristics of a conventional laser light source device.

[0013] Figure 5 This is a diagram showing the results of a three-dimensional electromagnetic field simulation of the frequency response characteristics of the laser light source device according to the first embodiment.

[0014] Figure 6 This is a diagram showing a circuit configuration of a laser light source device according to the second embodiment.

[0015] Figure 7 It is a plan view showing a part of the laser light source device involved in Embodiment 3.

[0016] Figure 8 It is along Figure 7 A cross-sectional view of the I-II cut.

[0017] Fig. 9 This is a cross-sectional view of a portion of the laser light source device according to the fourth embodiment.

[0018] Fig.10 This is a cross-sectional view of a portion of the laser light source device according to the fifth embodiment.

[0019] Fig.11 It is a perspective view showing a laser light source device according to the sixth embodiment.

[0020] Fig.12 It is a cross-sectional view showing a laser light source device according to the seventh embodiment.

[0021] Fig.13 It is a side view showing the laser light source device involved in Embodiment 8. DETAILED DESCRIPTION

[0022] The laser light source device according to the embodiment will be described with reference to the drawings. The same reference numerals are used for the same or corresponding components, and duplicate description may be omitted.

[0023] Implementation Method 1

[0024] Figure 11 is a perspective view showing a laser light source device according to Embodiment 1. The metal stem 1 is a plate-shaped stem base made of a metal material such as Cu with a high thermal conductivity and Au plating applied to the surface.

[0025] The leads 2a, 2b, and 2c penetrate the metal stem 1. The support block 3 is mounted on the metal stem 1. The support block 3 is a block made of a metal material having Au plating applied to the surface of a material with high thermal conductivity such as Cu, for example.

[0026] The dielectric substrate 4 is mounted on the side of the support block 3. The dielectric substrate 4 is, for example, a ceramic plate such as aluminum nitride (AlN). The differential drive signal lines 5a, 5b and the ground conductor 5c are Au plating and metallization patterns formed on the dielectric substrate 4. The differential drive signal lines 5a, 5b are coplanar lines or microstrip lines, and the impedance is equivalent to the output impedance of the signal generator. The ground conductor 5c is connected to the metal stem 1 by, for example, SnAgCu solder.

[0027] The semiconductor light modulator 6 is mounted on the dielectric substrate 4. The semiconductor light modulator 6 is an optical modulator integrated laser diode (EAM-LD) obtained by monolithically integrating a distributed feedback laser diode 6a and two electric field absorption optical modulators 6b and 6c. The electric field absorption optical modulators 6b and 6c have, for example, an InGaAsP quantum well absorption layer.

[0028] One end of the differential drive signal lines 5a and 5b is connected to the pins 2a and 2b through solders 7a and 7b, respectively. The solders 7a and 7b are made of materials such as SnAgCu. Conductive wires 8a and 8b made of Au and the like connect the other ends of the differential drive signal lines 5a and 5b to the electric field absorption type optical modulators 6b and 6c of the semiconductor optical modulation element 6, respectively. Conductive wire 8c made of Au and the like connects the pin 2c to the distributed feedback laser diode 6a. Wire bonding uses, for example, ultrasonic vibration crimping.

[0029] The metal stem 1 fixes the support block 3, the dielectric substrate 4, and the semiconductor light modulator 6. The support block 3 fixes the dielectric substrate 4 and the semiconductor light modulator 6. The dielectric substrate 4 fixes the semiconductor light modulator 6. Generally, the dielectric substrate 4 has an electrical insulation function and a heat transfer function. The heat generated in the semiconductor light modulator 6 is dissipated to a cooling member (not shown) on the negative side of the metal stem 1 in the Z-axis direction via the metal stem 1, the support block 3, and the dielectric substrate 4.

[0030] The distributed feedback laser diode 6a is powered via the pin 2c and the conductive wire 8c, and emits laser light. The electrical signal is input from the pins 2a and 2b, and is transmitted to the differential drive signal lines 5a and 5b via the solders 7a and 7b, and then applied to the plurality of optical modulators 6b and 6c of the semiconductor optical modulator element 6 via the conductive wires 8a and 8b. The grounding conductor 5c of the metal stem 1, the support block 3, and the dielectric substrate 4 connected to each other functions as an AC ground, and the electrical signal input to the pins 2a and 2b is electromagnetically coupled to the metal stem 1.

[0031] Laser light emitted from the distributed reflector laser diode 6a is modulated in sequence by the electric field absorption optical modulators 6b and 6c. The modulated laser light is radiated from the light emission point of the semiconductor optical modulator 6 along an optical axis perpendicular to the chip end face and parallel to the chip main surface.

[0032] Figure 2 1 is a top view showing the optical modulator portion of the semiconductor optical modulator element involved in Embodiment 1. The electric field absorption type optical modulators 6b, 6c and the transparent waveguide 9 are provided on the InP substrate 10. The semiconductor layers of the electric field absorption type optical modulators 6b, 6c are insulated and separated from each other by the insulating layer 11. The absorption layers of the electric field absorption type optical modulators 6b, 6c are optically connected through the transparent waveguide 9. The p-type electrode of the electric field absorption type optical modulator 6b is electrically connected to the p-type electrode pad 6bp through the power supply line 12. The p-type electrode of the electric field absorption type optical modulator 6c is electrically connected to the p-type electrode pad 6cp through the power supply line 13.

[0033] The n-type electrode pad 6bn of the electric field absorption type optical modulator 6b and the p-type electrode pad 6cp of the electric field absorption type optical modulator 6c are connected by a conductive line, etc., and the electric field absorption type optical modulator 6b and the electric field absorption type optical modulator 6c are connected in series. The p-type electrode pad 6bp of the electric field absorption type optical modulator 6b and the n-type electrode pad 6cn of the electric field absorption type optical modulator 6c are connected to the differential drive signal lines 5a and 5b, respectively.

[0034] Figure 3 1 is a diagram showing a circuit configuration of a laser light source device according to Embodiment 1. A differential electric signal output from a signal generator 14 is supplied to a semiconductor light modulator 6 via differential drive signal lines 5a, 5b and conductive lines 8a, 8b. In order to obtain a maximum voltage amplitude from the signal generator 14, a matching resistor 15 is connected in parallel to the semiconductor light modulator 6 via signal lines 16a, 16b.

[0035] The two electroabsorption optical modulators 6b and 6c of the semiconductor optical modulation element 6 are connected in series. Therefore, if the electrostatic capacitances of the electroabsorption optical modulators 6b and 6c are respectively C1 and C2, the combined electrostatic capacitance C is C=C1×C2 / (C1+C2).

[0036] Figure 4 This is a diagram showing the results of a three-dimensional electromagnetic field simulation of the frequency response characteristics of a conventional laser light source device. Figure 5 3D electromagnetic field simulation results showing the frequency response characteristics of the laser light source device involved in Embodiment 1. The vertical axis is the pass characteristic S21. In the existing laser light source device, there is one optical modulator. In Embodiment 1, two optical modulators of 1 / 2 length of the existing optical modulators are connected in series. In the existing laser light source device, the 3dB passband (cut-off frequency) is 33GHz, but in this embodiment, the 3dB passband is 63GHz. Therefore, it can be seen that in this embodiment, the gain is improved in the high frequency band.

[0037] As described above, in this embodiment, the semiconductor light modulator 6 has a plurality of electric field absorption type light modulators 6b and 6c separated from each other. As a result, the length of each light modulator is shortened compared to the past, so the electrostatic capacitance becomes smaller. Therefore, the gain relative to the frequency band is improved and a wide frequency band can be achieved. In addition, by using a plurality of electric field absorption type light modulators 6b and 6c, it is possible to ensure an extinction ratio equivalent to that of a conventional single light modulator.

[0038] In addition, the plurality of electric field absorption type optical modulators 6b and 6c are connected in series with each other between the first and second differential drive signal lines 5a and 5b for supplying differential signals to the semiconductor optical modulator element 6. In this way, since the input method of the electric signal to the semiconductor optical modulator element 6 is a differential drive method, the plurality of electric field absorption type optical modulators 6b and 6c can be driven with the same voltage as in the past.

[0039] In addition, in this embodiment, the temperature control module provided in the prior art is not used, so that the cost reduction and the reduction of the assembly cycle time due to the reduction of the number of parts can be achieved. However, if necessary according to the use environment, the temperature control module can also be installed on the metal pipe seat 1 or on the side of the support block 3.

[0040] Implementation Method 2

[0041] Figure 6 1 is a diagram showing a circuit structure of a laser light source device according to Embodiment 2. An electric field absorption type optical modulator 6b is connected between a first differential drive signal line 5a and a ground point. An electric field absorption type optical modulator 6c is connected between a second differential drive signal line 5b and a ground point. Matching resistors 15a and 15b are connected in parallel to the electric field absorption type optical modulators 6b and 6c, respectively. Even in the case where the electric field absorption type optical modulators 6b and 6c are connected to the first and second differential drive signal lines 5a and 5b in this way, a plurality of electric field absorption type optical modulators 6b and 6c can be driven with the same voltage as before. The other structures and effects are the same as those of Embodiment 1.

[0042] Implementation 3

[0043] Figure 7 It is a plan view showing a part of the laser light source device involved in Embodiment 3. Figure 8 It is along Figure 7 The matching resistor 15 is arranged between the upper surface of the dielectric substrate 4 and the lower surface of the semiconductor light modulator 6. As a result, it is not necessary to make the matching resistor 15 detour to the positive direction side of the semiconductor light modulator 6 in the Z axis, so the signal reflection loss caused by the impedance mismatch of the line part disappears. In addition, the dimension of the dielectric substrate 4 in the Z axis direction can be reduced.

[0044] However, the lower surface of the semiconductor light modulator 6 is bonded to the ground conductor 5c provided on the upper surface of the dielectric substrate 4 through the solder 17. Therefore, the ground conductor 5c is divided into two parts, and the matching resistor 15 is arranged in the gap between the ground conductor 5c divided into two parts. In this way, the ground conductor 5c and the matching resistor 15 can be separated. In addition, since the plating thickness of the ground conductor 5c is thicker than that of the matching resistor 15, the matching resistor 15 does not interfere with the semiconductor light modulator 6. The other structures and effects are the same as those of the first and second embodiments. In addition, when the present embodiment is combined with the second embodiment, the matching resistor 15 is replaced with matching resistors 15a and 15b.

[0045] Implementation 4

[0046] Fig. 9 is a cross-sectional view of a portion of the laser light source device according to Embodiment 4. Figure 7 1-2. Unlike the third embodiment, the matching resistor 15 is thicker than the ground conductor 5c, but a groove 18 is provided on the lower surface of the semiconductor light modulator 6. Thus, the matching resistor 15 does not interfere with the semiconductor light modulator 6. The other structures and effects are the same as those of the third embodiment.

[0047] Implementation method 5

[0048] Fig.10 is a cross-sectional view of a portion of the laser light source device according to Embodiment 5. Figure 7 In the third embodiment, the matching resistor 15 is provided on the upper surface of the dielectric substrate 4, but in the present embodiment, the matching resistor 15 is provided on the lower surface of the semiconductor light modulator 6. The other structures and effects are the same as those in the third embodiment.

[0049] Implementation 6

[0050] Fig.111 is a three-dimensional diagram of a laser light source device according to Embodiment 6. The light receiving element 19 is mounted on the metal stem 1 and is arranged on the negative side of the Z axis of the semiconductor light modulator 6. The light receiving element 19 is connected to the pin 21 via the conductive wire 20. The light receiving element 19 receives the back light of the semiconductor light modulator 6 and converts it into an electrical signal. The electrical signal is transmitted to the pin 21 via the connected conductive wire 20. Thus, although the number of pins passing through the metal stem 1 increases by one, the intensity of the back light of the semiconductor light modulator 6 can be monitored. Thus, the LD drive current can be controlled in such a way that the light output is constant. The other structures and effects are the same as those of Embodiments 1 to 5.

[0051] Implementation 7

[0052] Fig.12 2 is a cross-sectional view showing a laser light source device according to Embodiment 7. The cover 22 is bonded to the metal stem 1 to hermetically seal the semiconductor light modulator 6 and the like. The lens 23 is provided on the cover 22. The lens 23 is, for example, glass composed of SiO2, and focuses or converts the laser light emitted from the semiconductor light modulator 6 into parallel light. Thus, the airtightness of the semiconductor light modulator 6 and the like mounted on the metal stem 1 can be ensured. Moreover, the moisture resistance and the anti-interference performance can also be improved. The other structures and effects are the same as those of Embodiments 1 to 6.

[0053] Implementation 8

[0054] Fig.13 1 is a side view showing a laser light source device according to Embodiment 8. The lens 23 is bonded to the dielectric substrate 4. An epoxy resin adhesive is used as a bonding material. The lens 23 is, for example, glass composed of SiO2, and focuses or converts the laser light emitted from the semiconductor light modulator 6 into parallel light. Thus, miniaturization can also be achieved by Embodiment 7. The other structures and effects are the same as those of Embodiments 1 to 6.

[0055] Description of Reference Numerals

[0056] 1…metal stem; 2a, 2b…pins; 3…support block; 4…dielectric substrate; 5a…first differential drive signal line; 5b…second differential drive signal line; 5c…ground conductor; 6…semiconductor optical modulator; 6b, 6c…electric field absorption optical modulator; 8a, 8b…conductive wire; 15…matching resistor; 18…groove; 19…light receiving element; 22…cover; 23…lens.

Claims

1. A laser light source device, characterized in that: have: Metal pipe socket; A pin, passing through the metal tube seat; A support block is installed on the metal pipe seat; a dielectric substrate mounted on a side of the support block; A signal line, formed on the dielectric substrate, one end of which is connected to the pin; A semiconductor light modulation element mounted on the dielectric substrate; as well as A conductive wire connects the other end of the signal line to the semiconductor light modulation element, The semiconductor light modulation element has a plurality of light modulators separated from each other. The signal line includes a first differential drive signal line and a second differential drive signal line for supplying a differential signal to the semiconductor light modulation element. The plurality of optical modulators are connected in series with each other between the first differential drive signal line and the second differential drive signal line.

2. The laser light source device according to claim 1, characterized in that: The absorption layers of the plurality of light modulators are optically connected via a transparent waveguide, The plurality of optical modulators modulate the laser light in sequence.

3. The laser light source device according to claim 1 or 2, characterized in that: A light receiving element is also provided, and the light receiving element is mounted on the metal stem and receives the back light of the semiconductor light modulation element.

4. The laser light source device according to claim 1 or 2, characterized in that: Also available: a cover, engaged with the metal stem, to hermetically seal the semiconductor light modulation element; and The lens is provided on the cover and focuses the laser light emitted from the semiconductor light modulation element or converts it into parallel light.

5. The laser light source device according to claim 1 or 2, characterized in that: A lens is further provided, the lens being bonded to the dielectric substrate and converging or parallelizing the laser light emitted from the semiconductor light modulator.

6. A laser light source device, characterized in that: have: Metal pipe socket; A pin, passing through the metal tube seat; A support block is installed on the metal pipe seat; a dielectric substrate mounted on a side of the support block; A signal line, formed on the dielectric substrate, one end of which is connected to the pin; A semiconductor light modulation element mounted on the dielectric substrate; A conductive wire connecting the other end of the signal line to the semiconductor light modulation element; as well as A matching resistor is connected in parallel with the semiconductor light modulation element, The semiconductor light modulation element has a plurality of light modulators separated from each other. The matching resistor is arranged between the upper surface of the dielectric substrate and the lower surface of the semiconductor light modulation element.

7. The laser light source device according to claim 6, characterized in that: further comprising a ground conductor provided on the upper surface of the dielectric substrate, The lower surface of the semiconductor light modulator is bonded to the ground conductor. The matching resistor is arranged in a gap of the ground conductor divided into two parts.

8. The laser light source device according to claim 7, characterized in that: The ground conductor is thicker than the matching resistor.

9. The laser light source device according to claim 6 or 7, characterized in that: A groove is provided on the lower surface of the semiconductor light modulation element.

10. The laser light source device according to claim 6 or 7, characterized in that: The matching resistor is disposed on the lower surface of the semiconductor light modulation element.

11. The laser light source device according to claim 6 or 7, characterized in that: A light receiving element is also provided, and the light receiving element is mounted on the metal stem and receives the back light of the semiconductor light modulation element.

12. The laser light source device according to claim 6 or 7, characterized in that: Also available: a cover, engaged with the metal stem, to hermetically seal the semiconductor light modulation element; and The lens is provided on the cover and focuses the laser light emitted from the semiconductor light modulation element or converts it into parallel light.

13. The laser light source device according to claim 6 or 7, characterized in that: A lens is further provided, the lens being bonded to the dielectric substrate and converging or parallelizing the laser light emitted from the semiconductor light modulator.

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