Light source device and method for manufacturing light source device

Abstract

To provide a light source device capable of maintaining good propagation characteristics of high-frequency signals driving an optical semiconductor light source element while suppressing cost increase.SOLUTION: A light source device has a signal feedthrough section 204 provided in a stem to transmit high-frequency signals, a high-frequency wiring board 103 on which an optical semiconductor light source element mounted on the stem and driven by the high-frequency signals, and a high-frequency line section 202 that transmits the high-frequency signals to the optical semiconductor light source element are formed, and a connection section 203 that connects the signal feedthrough section and the high-frequency line section, and the connection section has a characteristic impedance of a value between the value of the characteristic impedance of the signal feedthrough section and the value of the characteristic impedance of the high-frequency line section, and an effective dielectric constant of a value between the value of the effective dielectric constant of the signal feedthrough section and the effective dielectric constant of the high-frequency line section.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to optical communications technology. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a structure in which an optical semiconductor light source element such as a direct modulated laser (DML) or a distributed feedback (DFB) laser is mounted in a can-type package has been known.

[0003] Patent Document 1 discloses a method of directly connecting an optical semiconductor light source element to the mounting surface of a can-type package via a submount, thereby shortening the distance between the optical semiconductor light source element and the mounting surface, and connecting signal lines using only wire bonding.

[0004] However, in the method disclosed in Patent Document 1, since the optical semiconductor light source element is directly mounted on the submount, there is a problem that the degree of freedom of arrangement of the optical semiconductor light source element is low. In addition, there is also a problem that wire bonding at the connection part is likely to cause deterioration of high-frequency characteristics.

[0005] To address this issue, Patent Document 2 discloses a method for connecting the mounting surface of a can-type package to an optical semiconductor light source element using a high-frequency wiring board. This method allows the optical semiconductor light source element to be located away from the mounting surface, increasing the degree of freedom in arranging the optical semiconductor light source element. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2004-354642 A [Patent Document 2] JP 2011-108939 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the method disclosed in Patent Document 2 has a problem that it is difficult to suppress disturbance of high-frequency characteristics between the high-frequency wiring board and the signal feedthrough. In response to this problem, Patent Document 2 improves the high-frequency characteristics by providing a portion using glass and a portion using air as an insulator of the feedthrough adjacent to each other. However, this method has a problem that the structure of the feedthrough becomes complicated and the cost increases.

[0008] In order to solve the above problems, the present disclosure aims to provide a light source device and a manufacturing method for a light source device that can suppress cost increases while maintaining good propagation characteristics of a high-frequency signal that drives an optical semiconductor light source element. [Means for solving the problem]

[0009] In order to solve the above problems, the light source device of the present disclosure employs a method of optimizing the board width, which is normally treated as a constant, as an independent parameter in a high-frequency wiring board used in a communication can package structure.

[0010] Specifically, the light source device of the present disclosure is Stem and a signal propagation portion provided on the stem for transmitting a high-frequency signal; an optical semiconductor light source element mounted on the stem and driven by receiving the high frequency signal; a high-frequency wiring board on which a high-frequency line portion for transmitting the high-frequency signal to the optical semiconductor light source element is formed; a connection portion that connects the signal propagation portion and the high-frequency line portion, The connection portion is a characteristic impedance having a value between a characteristic impedance value of the signal propagation portion and a characteristic impedance value of the high-frequency line portion, The effective dielectric constant has a value between the effective dielectric constant of the signal propagation portion and the effective dielectric constant of the high-frequency line portion.

[0011] Further, a method for manufacturing a light source device according to the present disclosure includes the steps of: providing a signal propagation portion for transmitting a high frequency signal on the stem; an optical semiconductor light source element that is driven by receiving the high frequency signal is mounted on the stem; providing a high-frequency wiring board on the stem, the high-frequency wiring board including a high-frequency line portion that transmits the high-frequency signal to the optical semiconductor light source element and has a characteristic impedance and an effective dielectric constant different from those of the signal propagation portion; connecting the signal propagation portion and the high-frequency line portion; and The present invention is characterized in that the connection portion between the signal propagation portion and the high-frequency line portion has a characteristic impedance whose value is between that of the signal propagation portion and that of the high-frequency wiring board, and is adjusted so as to have an effective dielectric constant whose value is between that of the signal propagation portion and that of the high-frequency wiring board.

[0012] According to this, by using a simple method of adjusting the characteristic impedance and effective dielectric constant of the connection part that connects the high frequency wiring board and the signal propagation part, it is possible to provide a light source device that can maintain good propagation characteristics of the high frequency signal while suppressing an increase in cost. In addition, since the high frequency wiring board is used, the number and length of signal wire bonding for transmitting the high frequency signal can be suppressed.

[0013] The signal propagation portion is formed of a coaxial line, It is preferable that a coplanar line having a transmission line and a pair of ground electrodes positioned so as to sandwich the transmission line is formed on the high-frequency substrate.

[0014] This makes it possible to suppress electromagnetic radiation and improve the waveform quality of high frequency signals.

[0015] one of the pair of ground electrodes is grounded to a rear surface ground of the high-frequency wiring board by via grounding or castellation; It is preferable that the other of the pair of ground electrodes is grounded to the back surface ground by a sidewall metal provided so as to surround an outer periphery of the high frequency wiring board.

[0016] This makes it possible to obtain a coplanar line having desired high frequency characteristics even if the center of the signal line is offset from the center of the high frequency wiring board.

[0017] It is preferable that the center of the signal line of the transmission path is offset from the center of the high frequency wiring board.

[0018] Even if the center of the signal line is shifted from the center of the high-frequency wiring board in this manner, the light source device of the present disclosure can provide a coplanar line having desired high-frequency characteristics as described above.

[0019] an operating temperature adjustment mechanism for adjusting the operating temperature of the optical semiconductor light source element; It is preferable that the optical fiber further comprises a subcarrier substrate connected to the high-frequency wiring board by high-frequency connection means, on which the optical semiconductor light source element is mounted and on which a pattern for electrical connection to the coplanar line is formed.

[0020] In the present disclosure, since a high-frequency wiring board is used, it is not necessary to arrange the optical semiconductor light source element close to the mounting surface in order to improve the deterioration of high-frequency characteristics caused by wire bonding. In other words, the degree of freedom in arranging the optical semiconductor light source element is ensured while suppressing the disturbance of high-frequency characteristics. And, since the degree of freedom in arranging the optical semiconductor light source element is ensured in this way, the operating temperature adjustment mechanism can be arranged at an appropriate position inside the package, and the optical semiconductor light source element can be appropriately cooled.

[0021] It is preferable that the optical semiconductor light source element is an EML (Electro-absorption Modulated Laser) or a DML (Direct Modulated Laser), that the output waveguide is mounted with an inclination of 3 degrees or more with respect to the optical axis, and that a semiconductor optical amplifier is integrally integrated.

[0022] In this way, when a semiconductor optical amplifier is provided, wire bonding is required to drive the semiconductor optical amplifier, and interference due to electromagnetic radiation of the high frequency signal tends to become significant. In contrast, the configuration of the present disclosure employs a coplanar line, which suppresses electromagnetic radiation and improves the waveform quality of the high frequency signal.

[0023] The connection portion is a characteristic impedance having an intermediate value between a characteristic impedance value of the signal propagation portion and a characteristic impedance value of the high-frequency line portion, It is preferable that the effective dielectric constant of the signal propagation portion is intermediate between the effective dielectric constant of the high-frequency line portion and the effective dielectric constant of the signal propagation portion.

[0024] This makes it possible to provide a light source device that can more suitably maintain the propagation characteristics of high-frequency signals.

[0025] The above disclosures may be combined to the greatest extent possible. Effect of the Invention

[0026] According to the light source device of the present disclosure, it is possible to maintain good propagation characteristics of high frequency signals that drive optical semiconductor light source elements while suppressing increases in costs. [Brief description of the drawings]

[0027] [Figure 1] 1A and 1B are diagrams illustrating a communication can package structure of a light source device. [Diagram 2] 1A and 1B are diagrams illustrating a high-frequency wiring board and its surrounding structure. [Diagram 3] 4 is a graph illustrating transmission characteristics and reflection characteristics of a related light source device. [Figure 4] 4 is a graph illustrating transmission characteristics and reflection characteristics of the light source device according to the embodiment. [Diagram 5] 1A and 1B are diagrams illustrating a structure in which the distance between a high-frequency wiring board and a carrier board is narrowed. [Figure 6] 10A and 10B are diagrams illustrating that the optical semiconductor light source element is inclined at a predetermined angle with respect to the optical axis. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings are assumed to indicate the same components.

[0029] (Embodiment 1) A light source device 301 according to an embodiment of the present disclosure will be described with reference to FIGS. [Outline of communication package structure] FIG. 1 is a diagram for explaining the communication package structure of the light source device 301. FIG. 2 is a diagram for explaining the structure of the high-frequency wiring board 103 and its surroundings. The light source device 301 mainly includes a stem 113, a cap 110, a substrate part 107, an optical semiconductor light source element 111, an operating temperature adjustment mechanism 116, a signal pin 101, a post 106, and a high-frequency wiring board 103. In this embodiment, as shown in FIG. 2, a signal from the signal pin 101 is transmitted to the optical semiconductor light source element 111 via a signal feed-through part 204 in which the signal pin 101 and the sealing glass 102a are coaxially formed, a connection part 203 in which the connection substrate part 201 and the upper part of the signal pin 101 are connected, and a high-frequency line part 202. The signal feed-through part 204 functions as a "signal propagation part".

[0030] Specifically, the light source device 301 includes: Stem 113 and a signal feedthrough portion 204 provided on the stem 113 and configured to transmit a high-frequency signal; an optical semiconductor light source element 111 mounted on a stem 113 and driven by receiving a high-frequency signal; a high-frequency wiring board 103 on which a high-frequency line portion 202 for transmitting the high-frequency signal to an optical semiconductor light source element 111 is formed; a connection portion 203 that connects the signal feed-through portion 204 and the high-frequency line portion 202, The connection portion 203 is has a characteristic impedance between the characteristic impedance value of the signal feed-through portion 204 and the characteristic impedance value of the high-frequency line portion 202, The effective dielectric constant has a value between the effective dielectric constant of the signal feedthrough portion 204 and the effective dielectric constant of the high-frequency line portion 202 .

[0031] The manufacturing method of the light source device 301 is as follows: providing a signal feedthrough portion 204 for transmitting a high-frequency signal on the stem 113; An optical semiconductor light source element 111 that is driven by receiving a high-frequency signal is mounted on a stem 113; A high-frequency wiring board 103 on which a high-frequency line portion 202 for transmitting a high-frequency signal to an optical semiconductor light source element 111 is formed is provided on a stem 113; and Connecting the signal feed-through portion 204 and the high-frequency line portion 202; and The connection portion 203 includes adjusting the connection portion 203 to have a characteristic impedance whose value is between the characteristic impedance value of the signal feed-through portion 204 and the characteristic impedance of the high-frequency wiring board 103, and to have an effective dielectric constant whose value is between the effective dielectric constant value of the signal feed-through portion 204 and the effective dielectric constant value of the high-frequency wiring board 103.

[0032] The stem 113 is made of metal, and has a plurality of through holes penetrating the stem 113 in the vertical direction of the figure. The plurality of through holes are provided with a signal pin 101 for transmitting a high-frequency signal or a bias pin 114 for controlling other DC biases via one of the sealing glasses 102a and 102b. Each of the signal pin 101 and the bias pin 114 protrudes upward from the stem inner surface 112. The signal pin 101 and the bias pin 114 are connected to the stem 113 by the sealing glass 102a or 102b and function as a feedthrough. Each of the sealing glasses 102a and 102b is an insulator having a predetermined dielectric constant. The sealing glass 102a is formed to correspond to the signal pin 101, and the sealing glass 102b is formed to correspond to the bias pin 114. In this embodiment, one signal pin 101 is provided, and six bias pins 114a, 114b, 114c, 114d, 114e, and 114g are provided. In addition, one sealing glass 102a and six sealing glasses 102b are provided so as to correspond to the numbers of the signal pins 101 and the bias pins 114.

[0033] Specifically, either one of the sealing glasses 102a or 102b is press-fitted into the plurality of through holes. A compressive stress acts between the stem 113 and the sealing glasses 102a and 102b to maintain airtightness. A compressive stress also acts between the sealing glass 102a and the signal pin 101, and between the sealing glass 102b and each of the bias pins 114a, 114b, 114c, 114d, 114e, and 114f to maintain airtightness. In addition to the bias pins, the stem 113 may be provided with any number of pins for ground connection.

[0034] The stem 113 is sealed by a cap 110. The cap 110 is provided with an optical means 109.

[0035] On stem inner surface 112, an operating temperature adjustment mechanism 116, a substrate portion 107, and optical semiconductor light source element 111 are mounted in this order from the bottom. Operating temperature adjustment mechanism 116 is a heat sink that controls the temperature of optical semiconductor light source element 111. Operating temperature adjustment mechanism 116 is composed of a Peltier element, for example. The lower surface of operating temperature adjustment mechanism 116 is in contact with stem inner surface 112. Furthermore, the upper surface of operating temperature adjustment mechanism 116 is in contact with the lower surface of substrate portion 107. Heat generated when optical semiconductor light source element 111 is operating is dissipated to the outside via operating temperature adjustment mechanism 116 and stem 113.

[0036] The substrate unit 107 has a carrier substrate 107a and a sub-carrier substrate 107b. The lower surface of the carrier substrate 107a is in contact with the upper surface of the operating temperature adjustment mechanism 116. The sub-carrier substrate 107b is mounted on the carrier substrate 107a. The semiconductor optical light source elements 111 are mounted on the sub-carrier substrate 107b.

[0037] The optical semiconductor light source element 111 has a light exit port 117. The light emitted from the light exit port 117 is guided to the outside of the cap 110 via the optical means 109.

[0038] Post 106 is a structure provided for fixing high-frequency wiring board 103 in a predetermined position, but is not essential. High-frequency wiring board 103 has high-frequency line portion 202 and connection board portion 201. Connection board portion 201 is disposed so as to contact a portion of signal pin 101 that protrudes upward from stem inner surface 112. Connection board portion 201 and signal pin 101 are electrically connected by being in contact with each other.

[0039] 2, a signal from the signal pin 101 is transmitted to the optical semiconductor light source element 111 via the signal feed-through portion 204 in which the signal pin 101 and the sealing glass 102a are coaxially arranged, the connection portion 203 in which the connection board portion 201 and the upper portion of the signal pin 101 are connected, and the high-frequency line portion 202. Hereinafter, the characteristics of the signal feed-through portion 204, the connection portion 203, and the high-frequency line portion 202 will be described.

[0040] [Feed-through characteristics] The characteristic impedance of the signal feed-through portion 204 is determined by the diameter d1 of the signal pin 101, the relative dielectric constant of the sealing glass 102a, and the diameter d2 of the sealing glass 102a. The effective dielectric constant of the signal feed-through portion 204 is determined by the relative dielectric constant of the sealing glass 102a. The diameter d1 of the signal pin 101 depends on the manufacturing technology of the can package. The diameter d1 of the signal pin 101 can be easily realized up to about 0.2 mm in the smallest case. The relative dielectric constant of the sealing glass can be easily realized up to 4.0 in the case of a low sealing glass. From these, the diameter d1 at which 50Ω is obtained as the characteristic impedance of the signal feed-through portion 204 is expected to be about 1.0 mm. Since the signal feed-through portion 204 has a coaxial line structure, the effective dielectric constant at this time is 4.0, which is the same as the relative dielectric constant of the sealing glass 102a. In the present invention, the above line structure is used for detailed explanation, but the same discussion applies to signal pins and sealing glasses other than those described above.

[0041] [Connection characteristics] Next, the characteristics of the connection part 203 will be described. If the connection part 203 where the signal pin 101 and the connection board part 201 are in contact is not provided, the signal pin 101 is located in air with a relative dielectric constant of 1.0, so that the characteristic impedance of the signal pin 101 is higher than 50Ω and the effective dielectric constant is lower than 4.0. In contrast, in this embodiment, the connection board part 201 is provided so as to be in contact with the signal pin 101, so that the local characteristic impedance and effective dielectric constant of the connection part 203 are affected by the relative dielectric constant of the high-frequency wiring board 103 and change compared to when the signal pin 101 is located in air. By adjusting the relative dielectric constant, board thickness, and board width W of the high-frequency wiring board 103, it is possible to match the characteristic impedance of the connection part 203 to 50Ω and control the effective dielectric constant at the same time. Here, the dielectric constant and thickness of the high-frequency wiring board 103 have little freedom of adjustment due to the availability and processability of materials. Therefore, it is practical to mainly adjust the characteristic impedance and the effective dielectric constant by using the width W of the high-frequency wiring board 103. In this embodiment, the board width W refers to the width of the high-frequency wiring board 103 in the left-right direction in the figure. In other words, the board width W refers to the width of the high-frequency wiring board 103 in the direction perpendicular to the extension direction of the high-frequency line portion 202. A high-dielectric constant board having a relative dielectric constant of about 9.0, such as alumina or aluminum nitride, is often used as the material for the high-frequency wiring board 103. In this embodiment, the description will be given assuming these high-dielectric constant boards, but the same discussion will also be valid for high-dielectric constant boards other than those mentioned above.

[0042] [How to determine board width] Next, a method for determining the width W will be described in detail. Here, it is assumed that the signal feed-through portion 204 has a characteristic impedance Z1 and an effective dielectric constant ε1, the high-frequency line portion 202 on the high-frequency wiring board 103 has a characteristic impedance Z2 and an effective dielectric constant ε2, and the connection portion 203 between the signal pin 101 and the connection board portion 201 has a characteristic impedance Z and an effective dielectric constant ε. In this case, the optimum board width W is determined by increasing or decreasing the board width W of the high-frequency wiring board 202 to adjust the characteristic impedance Z to an intermediate value between Z1 and Z2, and to adjust the effective dielectric constant ε to an intermediate value between ε1 and ε2. Note that if both Z1 and Z2 can be regarded as 50Ω, Z is also 50Ω. Even if the above conditions cannot be satisfied by adjusting the board width W alone, the desired range of characteristic impedance and effective dielectric constant can be obtained by changing the thickness of the high-frequency wiring board 103 and re-optimizing the board width W.

[0043] FIG. 3 is a graph showing high-frequency characteristics of a conventional communication package structure not having the communication package structure of this embodiment. That is, FIG. 3 shows high-frequency characteristics in a configuration in which the signal pin 101 and the high-frequency wiring board 103 are connected by wire bonding or the like without contacting the signal pin 101 and the high-frequency wiring board 103. FIG. 4 is a graph showing high-frequency characteristics of the communication package structure of this embodiment. That is, FIG. 4 shows S parameters when the signal pin 101 and the high-frequency wiring board 103 are connected to the connection part 203 via the connection part 203. Comparing the graphs, it can be seen that the reflection characteristic S11 and the transmission characteristic S21 are improved by providing the connection part 203. Specifically, comparing the graphs, it can be seen that the absolute value of the transmission loss in dB units is reduced to half or less in the frequency range of 25 GHz to 35 GHz, and is sufficiently below 1 dB. Also, from FIGS. 3 and 4, it can be seen that the improvement in high-frequency characteristics is more remarkable on the high-frequency side, and that a wider-band communication device can be obtained by using the communication package structure of the present invention. In this manner, in this embodiment, the board width of the high frequency wiring board 103, which is usually treated as a constant, is optimized as an independent parameter, thereby suppressing the disturbance of the high frequency characteristics at the connection portion 203. This makes it possible to provide a light source device 301 that can maintain good propagation characteristics of a high frequency signal simply and at low cost. In addition, since the high frequency wiring board 103 is used, the number and length of wire bonding between the optical semiconductor light source element 111 and the mounting surface can be suppressed. Therefore, in this embodiment, it is not necessary to arrange the optical semiconductor light source element 111 close to the mounting surface in order to improve the deterioration of the high frequency characteristics due to wire bonding. That is, in this embodiment, the degree of freedom of arrangement of the optical semiconductor light source element 111 is secured while suppressing the disturbance of the high frequency characteristics. And, since the degree of freedom of arrangement of the optical semiconductor light source element 111 is secured in this manner, the operating temperature adjustment mechanism 116 can be arranged at an appropriate position inside the package.

[0044] (Embodiment 2) A light source device 301 according to an embodiment of the present disclosure will be described with reference to Figures 1, 2, and 5. Figure 5 is a diagram illustrating a structure in which the distance between the high-frequency wiring board 103 and the carrier board 107a is narrowed.

[0045] [Layout decision for high frequency wiring board] In the communication package structure, the layout of each component is determined according to the function of each component, layout restrictions between the components, and the like. Here, in the first embodiment, if the above-mentioned optimization of the board width W is performed by using a high dielectric constant board for the high frequency wiring board 103, the board width W becomes smaller (narrower), and the layout of the high frequency wiring board 103 relative to the optical semiconductor light source element 111 and the like may deviate from the above-mentioned layout restrictions. For example, the distance D between the high frequency wiring board 103 and the carrier board 107a shown in FIG. 2 becomes larger than a desired value. Even in this case, it is possible to narrow the distance D to a distance D' by arranging the high frequency wiring board 103 closer to the carrier board 107a as shown in FIG. 5. This allows the layout of the high frequency wiring board 103 relative to the carrier board 107a to be within the above-mentioned layout restrictions.

[0046] [Suppression of electromagnetic radiation caused by rearrangement of high frequency wiring boards] However, when the above-described arrangement of the high-frequency wiring board 103 is adjusted while maintaining the optimized board width W, the signal line center O of the high-frequency line portion 202 may not necessarily coincide with the center line C of the high-frequency wiring board 103.

[0047] For this reason, in this embodiment, a coplanar line is adopted as the high-frequency line portion 202, which is composed of a transmission line 208 and a pair of ground electrodes 104b and 104c provided on the high-frequency wiring board 103 so as to sandwich the signal line. That is, the transmission line 208 and the pair of ground electrodes 104b and 104c are provided on the same surface of the high-frequency wiring board 103. A part of the transmission line 208 and a part of the pair of ground electrodes 104b and 104c are provided on the subcarrier board 107b. A part of the high-frequency line portion 202 provided on the subcarrier board 107b is connected to the high-frequency line portion 202 on the high-frequency wiring board 103 via a signal wire bonding 122. Specifically, the wire bonding 122 directly and electrically connects the subcarrier board 107b and the high-frequency wiring board 103. In this embodiment, the wire bonding 122 includes a signal wire bonding that directly and electrically connects the subcarrier substrate 107b and the transmission line 208, and a GND wire bonding that directly and electrically connects the carrier substrate 107b and a pair of ground electrodes 104b and 104c. Each wire bonding can be double-bonded by bonding using two wires. This further improves the transmission characteristics. The wire length can be changed arbitrarily. The shorter the wire length, the better the characteristics. The ground electrode 104c is grounded to the back ground of the high frequency wiring board 103 through the via grounds 105a, 105b, and 105c, or by castellation. The ground electrode 104b is grounded to the back ground of the high frequency wiring board 103 through the sidewall metal 104a provided so as to surround the outer peripheral surface of the high frequency wiring board 103. Since the ground electrodes 104b and 104c are grounded in this manner, it is possible to obtain a coplanar line having desired high frequency characteristics even if the signal line center O is located at a position displaced from the center line C of the high frequency wiring board 103. That is, in this embodiment, by employing a coplanar line, it is possible to suppress the generation of electromagnetic radiation of the signal and suppress deterioration of the waveform quality of the signal. Note that, as shown in FIG. 2, only the transmission line portion 208 may be specified as the high frequency line portion 202.

[0048] The reason why a coplanar line having the above-described high-frequency characteristics is possible is that by providing the transmission line 208 and the ground electrodes 104b, 104c on the same surface of the high-frequency wiring board 103, the propagation mode of the coplanar line can be concentrated in the vicinity of the transmission line 208, and the propagation characteristics are not affected even if the board width W changes. In contrast, if a microstrip line is used instead of the coplanar line, the ground electrode is provided on the surface opposite the transmission line, and the propagation mode is likely to extend beyond the board width W of the high-frequency wiring board 103, and an asymmetric mode is generated with respect to the center O of the signal line. This causes electromagnetic radiation of the signal, which causes a problem of deterioration in the waveform quality of the signal.

[0049] In this manner, in this embodiment, by adopting a coplanar line with little electromagnetic radiation as the wiring of the high-frequency wiring board 103, it is possible to increase the adjustment range of the board width W and adjust the position between the optical semiconductor light source element 111 and the high-frequency wiring board 103, so as to move the position of the high-frequency wiring that is usually placed in the center of the high-frequency wiring board 103 to a position other than the center.

[0050] (Embodiment 3) A light source device 301 according to an embodiment of the present disclosure will be described with reference to Fig. 1 and Fig. 6. Fig. 6 is a diagram illustrating that an optical semiconductor light source element 111 is inclined at a predetermined angle with respect to an optical axis 108.

[0051] The optical semiconductor light source element 111 is an EML (Electro-absorption Modulated Laser) or a DML (Direct Modulated Laser) 118, and the output waveguide of the optical semiconductor light source element 111 is mounted with an inclination of 3° or more with respect to the optical axis 108. The reason for inclining the output waveguide of the optical semiconductor light source element 11 with respect to the optical axis 108 in this manner is that the laser light output has a directivity that is slightly inclined from the normal line of the output side end face of the optical semiconductor light source element 111, and therefore the optical semiconductor 111 needs to be rotated and mounted in accordance with the direction. The light emitted from the light exit 117 is guided to the outside of the cap 110 by the optical means 109. Specifically, the light emitted from the light exit 117 is aligned with the optical axis 108 by a lens section or a mirror section provided inside the optical means 109, and then guided to the outside of the cap 110. The arrangement of the optical semiconductor light source element 111 is determined according to the function and characteristics of the optical means 109. In this embodiment, high frequency wiring board 103 is used, and the degree of freedom in arranging semiconductor light source element 111 is high, so that semiconductor light source element 111 can be appropriately arranged according to the function and structure of optical means 109 .

[0052] Moreover, the semiconductor optical amplifier 119 is integrated in the optical semiconductor light source element 111, which makes it possible to increase the power obtained from the emitted light. In the optical semiconductor light source element 111 containing the semiconductor optical amplifier 119, in addition to the signal wire bonding 121 of the EML or DML 118, the wire bonding 120 for driving the semiconductor optical amplifier 119 is also required, and there is a problem that interference due to electromagnetic radiation of the signal is likely to become significant. Specifically, since the signal wire bonding 121 is for RF signals, it is preferable that it has as low reflection and radiation as possible. For this reason, the wire bonding 121 is connected at the shortest distance technically possible, and only the wire bonding 121 is connected by a bonder of a different model from the other wire bondings. Furthermore, since the wire bonding 120 is for DC bias, it is necessary to connect it to the bias pin 114a of the stem 113 with a fairly long wire length. However, other than that, there are few restrictions on the length and shape of the wire bonding 120. In contrast, in this embodiment, a coplanar line is introduced and the line width of the transmission line 208 is narrowed, thereby making it possible to suppress electromagnetic radiation and improve the waveform quality of the signal. [Explanation of symbols]

[0053] 101: Signal pin 102a, 102b: sealing glass 103: High frequency wiring board 104a: Sidewall metal 105a, 105b, 105c: via ground 106: Post 107: Circuit board section 107a: Carrier substrate 107b: Subcarrier board 108: Optical axis 109:Optical means 110: Cap 111: Optical semiconductor light source element 112: Stem inner surface 113: Stem 114, 114a, 114b, 114c, 114d, 114e, 114f: Bias pin 116: Operating temperature adjustment mechanism 117: Light exit port 118: EML or DML 119: Semiconductor optical amplifier 120: Wire bonding 121, 122: Signal wire bonding 201: Connection board section 202: High frequency line section 203: Connection 204: Signal feed-through section 208: Transmission line 301: Light source device

Claims

1. Stem and a signal propagation portion provided on the stem for transmitting a high-frequency signal; an optical semiconductor light source element mounted on the stem and driven by receiving the high frequency signal; a high-frequency wiring board on which a high-frequency line portion for transmitting the high-frequency signal to the optical semiconductor light source element is formed; a connection portion that connects the signal propagation portion and the high-frequency line portion, The connection portion is a characteristic impedance having a value between a characteristic impedance value of the signal propagation portion and a characteristic impedance value of the high-frequency line portion, an effective dielectric constant having a value between the effective dielectric constant of the signal propagation portion and the effective dielectric constant of the high-frequency line portion; Light source device.

2. The signal propagation portion is formed of a coaxial line, A coplanar line having a transmission line and a pair of ground electrodes positioned to sandwich the transmission line is formed on the high frequency substrate. The light source device according to claim 1 .

3. one of the pair of ground electrodes is grounded to a rear surface ground of the high-frequency wiring board by via grounding or castellation; the other of the pair of ground electrodes is grounded to the back surface ground by a sidewall metal provided so as to surround an outer circumferential surface of the high frequency wiring board; The light source device according to claim 2 .

4. a center of the signal line of the transmission line is offset from a center of the high-frequency wiring board; The light source device according to claim 3 .

5. an operating temperature adjustment mechanism for adjusting the operating temperature of the optical semiconductor light source element; a subcarrier substrate connected to the high-frequency wiring board by a high-frequency connection means, on which the optical semiconductor light source element is mounted and on which a pattern electrically connected to the coplanar line is formed; The light source device according to claim 2 .

6. The optical semiconductor light source element is an EML (Electro-absorption Modulated Laser) or a DML (Direct Modulated Laser), an output waveguide is mounted with an inclination of 3 degrees or more with respect to an optical axis, and a semiconductor optical amplifier is integrated. The light source device according to claim 2 .

7. The connection portion is a characteristic impedance having an intermediate value between a characteristic impedance value of the signal propagation portion and a characteristic impedance value of the high-frequency line portion, an effective dielectric constant having an intermediate value between an effective dielectric constant value of the signal propagation portion and an effective dielectric constant value of the high-frequency line portion; The light source device according to claim 1 .

8. providing a signal propagation portion for transmitting a high frequency signal on the stem; an optical semiconductor light source element that is driven by receiving the high frequency signal is mounted on the stem; providing a high-frequency wiring board on the stem, the high-frequency wiring board having a high-frequency line portion for transmitting the high-frequency signal to the optical semiconductor light source element; connecting the signal propagation portion and the high-frequency line portion; and adjusting a connection portion between the signal propagation portion and the high-frequency line portion to have a characteristic impedance having a value between a characteristic impedance value of the signal propagation portion and a characteristic impedance value of the high-frequency wiring board, and to have an effective dielectric constant having a value between an effective dielectric constant value of the signal propagation portion and an effective dielectric constant value of the high-frequency wiring board, A method for manufacturing a light source device.

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