Laser light emitting device and optical module

Abstract

The laser light emitting device (31) includes a substrate (40), a laser light source (51) held on a surface (40a) of the substrate and generating laser light, a modulation section (52) held on the surface of the substrate and modulating the laser light generated by the laser light source and emitting it in a predetermined direction (D1) from one end of the substrate in a predetermined direction along the surface of the substrate, and a signal line (43) formed on the surface of the substrate and transmitting a modulation signal for modulating the laser light generated by the laser light source to the modulation section, and the signal line is positioned at a position closer to one end of the substrate than the other end.

Description

[Technical field]

[0001] The present disclosure relates to a laser beam emitting device and an optical module. [Background technology]

[0002] Conventionally, an optical module has been disclosed that includes a laser diode that outputs laser light, a semiconductor optical modulator that modulates and emits the laser light, and a carrier that holds a semiconductor optical integrated element (laser light emitting device) having the laser diode and the semiconductor optical modulator (see Patent Document 1). In this optical module, the semiconductor optical integrated element and a signal line that guides a modulated signal to the semiconductor optical integrated element are arranged on a main surface of the carrier made of an insulator. In addition, this signal line is formed so as to extend in the longitudinal direction of the carrier from a position close to one end face of the carrier to a position close to the other end face. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-74057 A Summary of the Invention [Problem to be solved by the invention]

[0004] A semiconductor optical integrated device such as that described in Patent Document 1 has a problem in that, depending on the frequency of the modulated signal input to the semiconductor optical modulator, the modulated signal transmitted may be degraded due to resonance of the signal line.

[0005] The present disclosure is devised to solve the above-mentioned problems, and has an object to provide a laser beam emitting device and an optical module capable of suppressing degradation of a transmitted modulated signal. [Means for solving the problem]

[0006] The laser light emitting device according to the present disclosure comprises: Laser lightand a laser light source that modulates the laser light generated by the laser light source. Place Directed Direction On the other hand A modulation unit that outputs and a substrate holding the modulator thereon; and a signal line that transmits a modulation signal for modulating the laser light generated by the laser light source to the modulation section, the signal line being disposed at a position closer to one end of the substrate than to the other end, and the modulation signal being input from one side. and is formed continuously over the front and back surfaces of the substrate. It is characterized by the above. Effect of the Invention

[0007] According to the present disclosure, it is possible to shorten the signal line that transmits the modulated signal compared to the conventional art, thereby suppressing resonance of the signal line and suppressing deterioration of the modulated signal. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view showing an optical module according to a first embodiment, viewed from the front side. [Diagram 2] 1 is a perspective view showing the optical module according to the first embodiment as viewed from the rear side. [Diagram 3] FIG. 2 is an enlarged view showing the optical module according to the first embodiment. [Figure 4] 1 is a perspective view showing a laser beam emitting device according to a first embodiment, as viewed from the front side. [Diagram 5] 5 is a perspective view showing the front side of the laser beam emitting device according to the first embodiment, viewed from a direction different from that of FIG. 4. [Figure 6] 6 is a graph showing a comparison result of an S21 characteristic simulation depending on the length of the signal line according to the first embodiment. [Figure 7] FIG. 11 is a perspective view showing a laser beam emitting device according to a second embodiment, as viewed from the front side. [Figure 8] FIG. 11 is a perspective view showing a laser beam emitting device according to a second embodiment, as viewed from the rear side. [Figure 9] FIG. 11 is a perspective view showing an optical module according to a third embodiment, as viewed from the front side. [Figure 10]FIG. 11 is a perspective view showing an optical module according to a fourth embodiment, as viewed from the front side. [Figure 11] FIG. 11 is a perspective view showing an optical module according to a fourth embodiment, as viewed from the rear side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Embodiment 1 First, a schematic configuration of an optical module 1 according to a first embodiment will be described with reference to Figs. 1 to 3. Fig. 1 is a perspective view showing the optical module 1 according to the first embodiment as viewed from the front side, and Fig. 2 is a perspective view showing the optical module 1 according to the first embodiment as viewed from the back side. The optical module 1 according to the first embodiment is a module for converting an electric signal into an optical signal and outputting it through an optical fiber. As shown in Figs. 1 and 2, the optical module 1 according to the first embodiment includes a module substrate 10, driving circuits 21, 22, 23, and 24 which are a plurality of driving circuits, laser light emitting devices 31, 32, 33, and 34 which are a plurality of laser light emitting devices, focusing lenses 61, 62, 63, and 64 which are a plurality of focusing lenses, a fiber array 70, various wirings, and the like.

[0010] The module substrate 10 serving as the second substrate is formed into a plate shape from an insulating material, and holds each component of the optical module 1. For example, the module substrate 10 is formed from synthetic resin, ceramics such as aluminum nitride, or a combination of these, and may be formed from LTCC (Low Temperature Co-fired Ceramics) or the like.

[0011] The driving circuits 21-24 as modulation signal output units are held on the module substrate 10, and output modulation signals to the corresponding laser light emitting devices. For example, the driving circuits 21-24 are held on the rear surface 10b of the module substrate 10, and generate modulation signals that are electrical signals to be output to the EML. Specifically, the driving circuits are configured by signal amplifiers, digital signal processing circuits, or the like.

[0012] The laser light emitters 31, 32, 33, and 34 emit modulated laser light based on a modulation signal from a corresponding one of the drive circuits 21 to 24. For example, the laser light emitters 31 to 34 are held on the surface of the module substrate 10 opposite to the surface holding the drive circuits 21 to 24. In other words, the laser light emitters 31 to 34 are held on the surface 10a of the module substrate 10. Specifically, the laser light emitters 31 to 34 are held on the surface 10a of the module substrate 10 in a state of being arranged side by side at a pitch of 1 mm or less. Also, for example, the laser light emitters 31 to 34 each emit laser light in a D1 direction shown in FIG. 1, which is a predetermined direction along the surface 10a of the module substrate 10. In the following description, a direction perpendicular to the D1 direction along the surface 10a of the module substrate 10 is also referred to as a lateral direction, and a direction perpendicular to the surface 10a of the module substrate 10 is also referred to as an up-down direction. The laser beam emitting devices 31 to 34 will be described in detail later.

[0013] The condenser lenses 61, 62, 63, and 64 are optically connected to the laser beam emitters 31 to 34, and collect the laser beams from the corresponding laser beam emitters among the laser beam emitters 31 to 34, and output the collected laser beams toward the fiber array 70. For example, the condenser lenses 61 to 64 are held on the surface 10a of the module substrate 10, and are disposed forward (downstream) of the laser beam emitters 31 to 34 in the D1 direction, and are disposed facing the corresponding laser beam emitters among the laser beam emitters 31 to 34. The condenser lenses 61 to 64 collect the laser beams emitted from the laser beam emitters 31 to 34 and traveling in a free space while diverging. In other words, the condenser lenses 61 to 64 convert the laser beams emitted from the laser beam emitters 31 to 34 and traveling in a free space while diverging into a collected beam.

[0014] The fiber array 70 is optically connected to the condenser lenses 61-64, and outputs the laser light from the condenser lenses 61-64 to an external device (not shown). For example, the fiber array 70 has an optical system 71 and an optical fiber 72. For example, the fiber array 70 is held on the surface 10a of the module substrate 10, and is disposed in front of the condenser lenses 61-64 in the D1 direction. For example, the optical system 71 is composed of lenses, mirrors, a multiplexer, a splitter, etc. (not shown).

[0015] The optical fiber 72 transmits the laser light from the optical system 71 to an external device (not shown). For example, the optical fiber 72 has a mode field diameter 4 to 5 times that of the laser light emitting devices 31 to 34, and is arranged so that the distance from the condenser lenses 61 to 64 to the optical fiber 72 is 4 to 5 times that from the laser light emitting devices 31 to 34 to the condenser lenses 61 to 64. Specifically, the condenser lenses 61 to 64 are arranged close to each other, at about 200 um, in order to sufficiently capture the laser light from the laser light emitting devices 31 to 34, and the optical fiber 72 is arranged so that the distance to the condenser lenses 61 to 64 is about 800 um to 1 mm.

[0016] Fig. 3 is an enlarged view showing the optical module 1 according to the first embodiment. As shown in Fig. 2 and Fig. 3, the optical module 1 includes wirings 14, 15, 16, wirings 11, 12, 13, and wirings W1, W2, W3 that transmit modulation signals from the drive circuits 21-24 to the laser light emitters 31-34. Note that the configurations of the drive circuits 22-24 and the laser light emitters 32-34 of the optical module 1 are similar to the configurations of the drive circuit 21 and the laser light emitter 31, so the configurations of the drive circuit 21 and the laser light emitter 31 will be described, and the configurations of the drive circuits 22-24 and the laser light emitters 32-34 will be omitted.

[0017] The wirings 14 to 16 are electrically connected to the respective terminals of the drive circuit 21. For example, the wirings 14 and 15 are electrically connected to a ground terminal of the drive circuit 21, and the wiring 16 is electrically connected to a signal terminal of the drive circuit 21 to transmit a modulation signal. Furthermore, for example, the wirings 14 to 16 extend in a direction along the front surface 10a of the module substrate 10 and are formed on the back surface 10b. Furthermore, for example, the wirings 14 to 16 are formed of a conductive metal film.

[0018] The wirings 11 to 13 are electrically connected to the wirings 14 to 16, respectively. For example, the wirings 11 and 12 are electrically connected to a ground terminal of the drive circuit 21 via the wirings 14 and 15, and the wiring 13 is electrically connected to a signal terminal of the drive circuit 21 via the wiring 16, to transmit a modulation signal. For example, the wirings 11 to 13 extend in a direction along the surface 10a of the module substrate 10 and are formed on the surface 10a. For example, the wirings 11 to 13 are electrically connected to the wirings 14 to 16, respectively, by vias (not shown) formed along the up-down direction. For example, the wirings 11 to 13 are formed of a conductive metal film.

[0019] The wirings W1 to W3 electrically connect the wirings 11 to 13 and the laser light emitting device 31, respectively. For example, the wirings W1 and W2 are electrically connected to a ground terminal of the driving circuit 21 via the wirings 11 and 12, and the wiring W3 is electrically connected to a signal terminal of the driving circuit 21 via the wiring 13 to transmit a modulation signal. Also, for example, the wirings W1 to W3 are formed of conductive metal wires, and connect the wirings 11 to 13 and the laser light emitting device 31 by wire bonding. Specifically, the wirings W1 to W3 are formed of gold wires.

[0020] In this way, the optical module 1 includes four driving circuits, four laser light emitting devices, four condensing lenses, and a fiber array, and is configured as a 4-channel optical module that converts a modulated signal, which is an electrical signal, into an optical signal and outputs the optical signal via an optical fiber. For example, the optical module 1 is configured to have a total transmission capacity of 800 Gbps by operating each of the four laser light emitting devices at 100 GBaud-PAM4. Note that the number of driving circuits, laser light emitting devices, and condensing lenses is not limited to four, and may be one, or may be two or more other than four.

[0021] 4 to 6, a detailed configuration of the laser beam emitter 31 will be described. Note that since the configurations of the laser beam emitters 32 to 34 are similar to that of the laser beam emitter 31, the configuration of the laser beam emitter 31 will be described and the configurations of the laser beam emitters 32 to 34 will be omitted.

[0022] Fig. 4 is a perspective view showing the laser beam emitting device 31 according to the first embodiment as viewed from the side of the front surface 40a, and Fig. 5 is a perspective view showing the laser beam emitting device 31 according to the first embodiment as viewed from a different direction from that of Fig. 4. As shown in Figs. 4 and 5, the laser beam emitting device 31 includes a substrate 40 as a first substrate, wiring 41, wiring 43, wiring 44, wiring W4, wiring W5, an EML (Electro-absorption modulator laser) 50, and a termination resistor R1.

[0023] The substrate 40 is formed in a plate shape from an insulating material, and holds each component of the laser light emitting device 31. For example, the substrate 40 is formed in a plate shape along the D1 direction in which the module substrate 10 extends, and is held on the surface 10a of the module substrate 10. Specifically, the substrate 40 is formed in a plate shape whose length in the D1 direction is greater than its lateral length, and is held on the surface 10a of the module substrate 10. In addition, for example, the substrate 40 is formed from synthetic resin, ceramics such as aluminum nitride, or a combination thereof, and may be formed from LTCC (Low Temperature Co-fired Ceramics) or the like.

[0024] The wiring 41 and the wiring 43 are electrically connected to the wirings W1 to W3. For example, the wiring 41 is electrically connected to a ground terminal of the driving circuit 21 via the wiring W1 and the wiring W2, and the wiring 43 is electrically connected to a signal terminal of the driving circuit 21 via the wiring W3 to transmit a modulation signal. Also, for example, the wiring 41 and the wiring 43 extend in a direction along the surface 40a of the substrate 40 and are formed on the surface 40a. Also, for example, the wiring 41 and the wiring 43 are formed of a conductive metal film.

[0025] The EML 50 has a laser light source 51 that receives power to generate laser light, and a modulation section 52 that modulates and emits the laser light generated by the laser light source 51. For example, the EML 50 is held on the surface 40a of the substrate 40 via wiring 41 by soldering or the like. For example, the laser light source 51 is composed of a distributed feedback laser diode (DFB-LD). Also, for example, the laser light source 51 is formed so that the length in the direction D1, which is the longitudinal direction of the laser light source 51, is about 500 um.

[0026] The modulation unit 52 modulates the laser light generated by the laser light source 51 based on a modulation signal from the drive circuit 21. For example, the modulation unit 52 is disposed forward of the laser light source 51 in the D1 direction. For example, the modulation unit 52 modulates the intensity of the laser light generated by the laser light source 51 based on a voltage change of the modulation signal from the drive circuit 21, and emits the modulated laser light in the D1 direction from one end of the substrate 40 in the D1 direction along the surface 40a of the substrate 40. For example, the modulation unit 52 is configured by an electro-absorption modulator (EAM). For example, the modulation unit 52 is formed so that the length in the D1 direction is about 100 um, which is shorter than that of the laser light source 51, in order to reduce parasitic capacitance.

[0027] The termination resistor R1 electrically connects the wiring 44 and the wiring 41, and terminates the modulated signal from the drive circuit 21. For example, the termination resistor R1 is held on the surface 40a of the substrate 40, and the wiring 44 is formed on the surface 40a of the substrate 40.

[0028] The wiring W4 electrically connects the wiring 43 and the modulation unit 52. For example, the wiring W4 is formed of a conductive metal wire, and connects the wiring 43 and the modulation unit 52 by wire bonding. Specifically, the wiring W4 is formed of a gold wire. The wiring W5 electrically connects the wiring 44 and the modulation unit 52. For example, the wiring W5 is formed of a conductive metal wire, and connects the wiring 44 and the modulation unit 52 by wire bonding. Specifically, the wiring W5 is formed of a gold wire.

[0029] In general, when a high-frequency signal is transmitted through a long wiring, the wiring may resonate, and the transmitted signal may deteriorate. In the laser light emitting device 31 according to the first embodiment, the wiring 43 serving as a signal line for transmitting a modulated signal is arranged at a position closer to an end of the substrate 40 in the D1 direction than an end of the substrate 40 in the opposite direction to the D1 direction, thereby reducing the length of the wiring 43 and suppressing the resonance of the wiring 43. In other words, in the laser light emitting device 31 according to the first embodiment, the modulation section 52 emits laser light from one end of the substrate 40, and the wiring 43 is arranged at a position closer to one end of the substrate 40 than the other end of the substrate 40, thereby reducing the length of the wiring 43 and suppressing the resonance of the wiring 43.

[0030] For example, the wiring 43 and the modulation section 52 are arranged closer to the end of the substrate 40 in the D1 direction than the center of the substrate 40 in the D1 direction. For example, the wiring 43 has a specific transmission section 43a that transmits the modulation signal along the direction opposite to the D1 direction. In other words, the wiring 43 is formed so that the modulation signal is input in the direction opposite to the D1 direction. For example, the wiring 43 is formed so that the connection section W31 with the wiring W3 is located forward in the D1 direction than the connection section W41 with the wiring W4. For example, the wiring 43 is formed so that both the connection section W31 with the wiring W3 and the connection section W41 with the wiring W4 are located forward in the D1 direction than the laser light source 51. For example, the wiring 43 is formed so that it is long in the D1 direction. For example, the wiring 43 is formed so that the end in the D1 direction is close to the end in the D1 direction of the substrate 40.

[0031] 6 is a graph showing the results of S21 characteristic simulation of the laser beam emitter 31 according to the first embodiment and a laser beam emitter having a longer wiring 43 as a signal line than the laser beam emitter 31. In FIG. 6, the results of the laser beam emitter 31 having the wiring 43 according to the first embodiment are shown by a broken line, and the results of the laser beam emitter having a longer wiring length corresponding to the wiring 43 than the laser beam emitter 31 are shown by a solid line. The simulation was performed with the wiring 43 of the laser beam emitter 31 being 300 um long, and the wiring of the laser beam emitter having a longer wiring length corresponding to the wiring 43 than the laser beam emitter 31 being 800 um long. The laser beam emitter having a longer wiring length shows resonance at around 67 GHz, but the laser beam emitter 31 according to the first embodiment shows that the resonance is suppressed and the characteristics of the 3 dB band are improved.

[0032] As described above, the laser light emitting device 31 of embodiment 1 includes a substrate 40, a laser light source 51 held on the surface 40a of the substrate and generating laser light, a modulation section 52 held on the surface 40a of the substrate 40 and modulating the laser light generated by the laser light source and emitting it in the direction D1 from one end of the substrate 40 in the direction D1 along the surface 40a of the substrate 40, and wiring 43 formed on the surface 40a of the substrate 40 and transmitting a modulation signal to the modulation section 52 to modulate the laser light generated by the laser light source, and the wiring 43 is positioned at a position closer to one end of the substrate 40 than the other end.

[0033] With this configuration, the laser light emitting device 31 according to the first embodiment can shorten the wiring 43 for transmitting the modulated signal compared to the conventional one. For example, the laser light emitting device 31 can shorten the length of the signal transmission path of the wiring 43 for transmitting the modulated signal compared to the conventional one. Also, for example, the laser light emitting device 31 can shorten the length L1 (see FIG. 4) in the D1 direction of the wiring 43 for transmitting the modulated signal compared to the conventional one. As a result, the laser light emitting device 31 according to the first embodiment can suppress the resonance of the wiring 43 by making the resonance frequency of the wiring 43 higher than the frequency of the transmitted signal, thereby suppressing the deterioration of the modulated signal. Also, the laser light emitting device 31 according to the first embodiment can obtain a good optical waveform even in high Baud rate modulation that requires a bandwidth exceeding 60 GHz, such as 100 GBaud-PAM4, which is a promising modulation method for the next-generation Ethernet.

[0034] Moreover, the optical module 1 according to the first embodiment includes a module substrate 10, a laser beam emitting device 31 held on the module substrate 10, and a driving circuit 21 held on the module substrate 10 and outputting a modulation signal for modulating the laser beam generated by the laser light source 51, the driving circuit 21 being held on the surface opposite to the surface 10a of the module substrate 10 which holds the laser beam emitting device 31. Thus configured, the optical module 1 can effectively utilize the surface 10a and the back surface 10b of the module substrate 10, and can improve the density of components and wiring on the surface 10a.

[0035] In the first embodiment, the optical module 1 is configured such that the laser light from the laser light emitting devices 31-34 is input to the fiber array via the condenser lenses 61-64, but is not limited thereto. The optical module may be configured to transmit the laser light emitted from the laser light emitting device to an external device, and may be configured to include, for example, a PLC (planar lightwave circuits) or a silicon photonics integrated circuit, and the laser light emitted from the laser light emitting device is input to the PLC or silicon photonics integrated circuit. When configured in this way, the optical module can be applied to the WDM method by using a PLC or a silicon photonics integrated circuit having a wavelength multiplexing function.

[0036] In the first embodiment, the drive circuits 21-24 are held on the surface of the module substrate 10 opposite to the surface holding the laser beam emitters 31-34, but this is not limiting. The drive circuits only need to be electrically connected to the laser beam emitters, and for example, the drive circuits may be held on the surface of the module substrate holding the laser beam emitters.

[0037] In the first embodiment, the wiring 43 is formed to be long in the D1 direction and is disposed closer to the end of the substrate 40 in the D1 direction than the center of the substrate 40 in the D1 direction, but is not limited thereto. The wiring 43 may be formed so that the length for transmitting a signal can be shortened compared to the conventional method by being disposed closer to the end of the substrate 40 in the D1 direction than the end of the substrate 40 in the opposite direction to the D1 direction. For example, the wiring 43 may be formed so that the lateral length is longer than the D1 direction, or a part of the wiring 43 may be disposed so as to be located on the opposite side to the D1 direction from the center of the substrate 40 in the D1 direction, or the connection part W31 with the wiring W3 may be formed to be located to the side of the connection part W41 with the wiring W4, or the wiring 43 may be formed so as to transmit a modulated signal along the side, or a part of the wiring 43 may be disposed so as to be close to the lateral end of the substrate 40.

[0038] In the first embodiment, the wirings 11 to 13 are formed on the front surface 10a of the module substrate 10, and the wirings 14 to 16 are formed on the rear surface 10b of the module substrate 10, but this is not limiting. These wirings may be formed so as to electrically connect the drive circuits 21 to 24 and the laser light emitting devices 31 to 34. For example, the wirings 11 to 13 may be formed on the rear surface 10b of the module substrate 10, the wirings 14 to 16 may be formed on the front surface 10a of the module substrate 10, the wirings 11 to 13 and the wirings 14 to 16 may be formed on either the front surface 10a or the rear surface 10b of the module substrate 10, or other wirings (not shown) may be formed between the wirings 11 to 13 and the wirings 14 to 16. In addition, when the module substrate is formed as a multilayer substrate, the wirings 11 to 13 and the wirings 14 to 16 may be formed partly or entirely in an inner layer of the module substrate.

[0039] In the first embodiment, the wirings 41, 43, and 44 are formed on the front surface 40a of the substrate 40, but are not limited thereto. These wirings may be formed so as to electrically connect the driving circuits 21 to 24, the laser light source 51, the modulation section 52, and the termination resistor R1, respectively. For example, the wirings 41, 43, and 44 may be partially formed on the rear surface 40b of the substrate 40, or may be partially formed on a side surface connecting the front surface 10a and the rear surface 40b of the substrate 40. In addition, when the substrate of the laser light emitting device is formed as a multilayer substrate, the wirings 41, 43, and 44 may be partially or entirely formed in an inner layer of the substrate.

[0040] In the first embodiment, the optical module 1 is configured such that the laser light emitting device 31 and the wirings 11 to 13 formed on the module substrate 10 are connected by wire bonding, but is not limited thereto. The optical module may be configured such that the laser light emitting device and the drive circuit are electrically connected, and may be configured such that, for example, the laser light emitting device and the drive circuit are electrically connected by contacting the wiring formed on the surface of the substrate of the laser light emitting device with the wiring formed on the surface of the module substrate.

[0041] Embodiment 2 Next, a laser beam emitter 231 according to embodiment 2 will be described with reference to Fig. 7 and Fig. 8. The laser beam emitter 231 according to embodiment 2 is different from the laser beam emitters 31 to 34 according to embodiment 1 in that wiring formed on a substrate 40 is different, but other configurations are similar, and the same configurations as those in embodiment 1 are denoted by the same reference numerals and description thereof will be omitted.

[0042] Fig. 7 is a perspective view showing the laser beam emitter 231 according to the second embodiment as viewed from the front surface 40a side, and Fig. 8 is a perspective view showing the laser beam emitter 231 according to the second embodiment as viewed from the back surface 40b side. As shown in Figs. 7 and 8, the laser beam emitter 231 includes a substrate 40, a wiring 241, a wiring 243, a wiring 44 (see Fig. 4), a wiring W4, a wiring W5, an EML50, and a termination resistor R1 (see Fig. 4).

[0043] The wiring 241 and the wiring 243 are electrically connected to the wirings 11 to 13 (see FIG. 3). For example, the wiring 241 is formed over the front surface 40a of the substrate 40, the side surface 40c of the substrate 40, and the rear surface 40b of the substrate, and the portion formed on the rear surface 40b of the substrate contacts the wirings 11 and 12, thereby being electrically connected to the wirings 11 and 12. Specifically, the wiring 241 is formed over the front surface 40a of the substrate 40, the side surface 40c of the substrate 40 in the D1 direction, and the rear surface 40b of the substrate, and the portion formed on the rear surface 40b of the substrate contacts the wirings 11 and 12, thereby being electrically connected to the wirings 11 and 12. For example, the wiring 241 is formed of a conductive metal film.

[0044] Also, for example, the wiring 243 is formed over the front surface 40a of the substrate 40, the side surface 40c of the substrate 40, and the rear surface 40b of the substrate, and the portion formed on the rear surface 40b of the substrate contacts the wiring 13, thereby being electrically connected to the wiring 13. Specifically, the wiring 243 is formed over the front surface 40a of the substrate 40, the side surface 40c in the D1 direction of the substrate 40, and the rear surface 40b of the substrate, and the portion formed on the rear surface 40b of the substrate contacts the wiring 13, thereby being electrically connected to the wiring 13. For example, the wiring 243 has a specific transmission section 243a that transmits a modulated signal along a direction opposite to the D1 direction, and a specific transmission section 243b that transmits a modulated signal along the D1 direction. Also, for example, the wiring 243 is formed by a conductive metal film.

[0045] In addition, when the laser beam emitting device is configured as in embodiment 2, the optical module is required to be configured so that the signal wiring and the ground wiring can be electrically separated, for example, by forming a metal bump on at least one of the rear surface of the substrate of the laser beam emitting device and the front surface of the module substrate.

[0046] In the second embodiment, the wiring 241 and the wiring 243 are formed on the front surface 40a, the side surface 40c in the D1 direction, and the back surface 40b of the substrate 40, but are not limited thereto. The wiring 241 and the wiring 243 may be formed so as to be electrically connected to the wirings 11 to 13, and for example, the wiring 241 and the wiring 243 may be formed on the front surface 40a and the side surface of the substrate 40, or may be formed on the front surface 40a of the substrate 40, the side surface of the substrate 40, and the back surface 40b, or may be formed so that the portion formed on the front surface 40a of the substrate 40 and the portion formed on the back surface 40b of the substrate 40 are electrically connected by vias formed along the vertical direction. In addition, in the optical module, the drive circuit and the laser emitting device are held on the front surface 10a of the module substrate 10, and the drive circuit is disposed rearward of the laser emitting device in the direction D1, and a portion formed on the rear surface of the substrate of the laser emitting device and each terminal of the drive circuit may be in contact with wiring formed on the front surface of the module substrate, thereby electrically connecting the laser emitting device and the drive circuit.

[0047] Embodiment 3 Next, an optical module 3 according to a third embodiment will be described with reference to Fig. 9. The optical module 3 according to the third embodiment is different from the optical module 1 according to the first embodiment in the configuration related to the wiring formed on the module substrate 10, the arrangement of the driving circuits 21-24, and the path of the laser light from the laser light emitting devices 31-34 to the optical fiber 72, but other configurations are similar, and the same reference numerals are used for the same configurations as those in the first embodiment, and the description thereof will be omitted.

[0048] Fig. 9 is a perspective view of the optical module 3 according to the embodiment 3, viewed from the front surface 10a side. As shown in Fig. 9, the optical module 3 includes a module substrate 10, drive circuits 21-24, laser light emitting devices 31-34, collimator lenses 361, 362, 363, and 364, condenser lenses 365, 366, 367, and 368, a fiber array 370, and various wirings.

[0049] The drive circuits 21-24 are held on the surface 10a of the module substrate 10 that holds the laser light emitters 31-34. For example, the drive circuits 21-24 are arranged forward in the D1 direction from the laser light emitters 31-34. Specifically, the drive circuits 21-24 are arranged forward in the D1 direction from the laser light emitters 31-34, and are electrically connected to the laser light emitters 31-34 by wiring formed on the surface 10a.

[0050] The collimator lenses 361-364 as parallel light conversion units are optically connected to the laser light emitters 31-34, convert the laser light from the corresponding one of the laser light emitters 31-34 into parallel light, and output the converted parallel light toward the condenser lenses 365-368. For example, the collimator lenses 361-364 are held on the surface 10a of the module substrate 10, and are disposed between the laser light emitters 31-34 and the driver circuits 21-24 in the direction D1, and are disposed opposite the corresponding one of the laser light emitters 31-34.

[0051] The condenser lenses 365-368 are optically connected to the collimator lenses 361-364, condense laser light, which is parallel light, from the corresponding collimator lens among the collimator lenses 361-364, and output the condensed laser light toward the fiber array 70. For example, the condenser lenses 365-368 are held on the front surface 10a of the module substrate 10, and are disposed forward of the collimator lenses 361-364 in the direction D1. Specifically, the condenser lenses 365-368 are held on the front surface 10a of the module substrate 10, and are disposed forward of the drive circuits 21-24 in the direction D1.

[0052] The fiber array 370 is optically connected to the condenser lenses 365-368, and outputs the laser light from the condenser lenses 365-368 to an external device (not shown). For example, the fiber array 370 has an optical system 371 and an optical fiber 72. For example, the fiber array 70 is held on the surface 10a of the module substrate 10, and is disposed in front of the condenser lenses 365-368 in the D1 direction.

[0053] In this way, the optical module 3 includes four driving circuits, four laser light emitting devices, four collimating lenses, four condensing lenses, and a fiber array, and is configured so that the laser light propagates in free space from the collimating lenses to the condensing lenses. This allows the driving circuits 21-24 to be disposed on the surface 40a of the module substrate 10 between the collimating lenses 361-364 and the condensing lenses 365-368. This eliminates the need to form vias between the laser light emitting devices 31-34 and the driving circuits 21-24, so that degradation of the modulated signal due to vias can be suppressed. The number of driving circuits, laser light emitting devices, and condensing lenses is not limited to four, and may be one, or may be two or more other than four.

[0054] The optical module may be configured to transmit the laser light emitted from the laser light emitting device to an external device, and may be configured to include, for example, a PLC or a silicon photonics integrated circuit, so that the laser light emitted from the laser light emitting device is input to the PLC or silicon photonics integrated circuit. In this configuration, the optical module can be applied to the WDM method by using a PLC or a silicon photonics integrated circuit having a wavelength multiplexing function.

[0055] Embodiment 4 Next, an optical module 4 according to a fourth embodiment will be described with reference to Fig. 10 and Fig. 11. The optical module 4 according to the fourth embodiment is different from the optical module 1 according to the first embodiment in the configuration relating to the wiring formed on the module substrate 10 and the arrangement of the drive circuits 21 to 24, but other configurations are similar, and the same configurations as those in the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

[0056] Fig. 10 is a perspective view showing an optical module 4 according to the fourth embodiment as viewed from the front surface 10a side, and Fig. 11 is a perspective view showing the optical module 4 according to the fourth embodiment as viewed from the back surface 10b side. As shown in Figs. 10 and 11, the optical module 4 includes a module substrate 10, drive circuits 21-24, laser beam emitters 31-34, wirings 11a, 12a, 13a, wirings 11b, 12b, 13b, and wirings 11c, 12c, 13c. The drive circuits 21-24 are held on the front surface 10a of the module substrate 10 that holds the laser beam emitters 31-34, and are disposed rearward (upstream) in the D1 direction from the laser beam emitters 31-34. In addition, since the configurations relating to the drive circuits 22-24 and the laser light emitters 32-34 of the optical module 4 are similar to the configurations relating to the drive circuit 21 and the laser light emitter 31, the configurations relating to the drive circuit 21 and the laser light emitter 31 will be described, and the configurations relating to the drive circuits 22-24 and the laser light emitters 32-34 will be omitted.

[0057] The wirings 11c to 13c are formed on the front surface 10a of the module substrate 10, and are electrically connected to the respective terminals of the drive circuit 21. The wirings 11b to 13b are formed on the rear surface 10b of the module substrate 10, and are electrically connected to the wirings 11c to 13c. The wirings 11a to 13a are formed on the front surface 10a of the module substrate 10, and are electrically connected to the wirings 11b to 13b and the laser light emission devices 31 to 34. For example, the wirings 11c to 13c and the wirings 11b to 13b, and the wirings 11b to 13b and the wirings 11a to 13a are connected by vias (not shown) formed in the vertical direction.

[0058] Configured in this manner, the optical module 4 of embodiment 4, for example, when it has an electrical connector upstream in the D1 direction from the driving circuits 21-24, is configured so that the input direction of power from the electrical connector, the transmission direction of electrical signals from the driving circuits 21-24 to the laser light emitters 31-34, and the emission direction of laser light from the laser light emitters 31-34 are aligned, thereby simplifying the layout of each wiring, making it possible to reduce design costs and miniaturize the product.

[0059] In addition, the present disclosure allows free combinations of the respective embodiments, or modifications of any of the components of the respective embodiments, or omission of any of the components of the respective embodiments. [Industrial Applicability]

[0060] A laser beam emitting device according to the present disclosure can be used, for example, to convert an electrical signal into an optical signal when transmitting the signal through an optical fiber. [Explanation of symbols]

[0061] 1 optical module, 3 optical module, 4 optical module, 10 module substrate (second substrate), 10a front surface, 10b rear surface, 11 wiring, 11a wiring, 11b wiring, 11c wiring, 12 wiring, 12a wiring, 12b wiring, 12c wiring, 13 wiring, 13a wiring, 13b wiring, 13c wiring, 14 wiring, 15 wiring, 16 wiring, 21 drive circuit (modulation signal output section), 22 drive circuit (modulation signal output section), 23 drive circuit (modulation signal output section), 24 drive circuit (modulation signal output section), 31 laser light emitting device, 32 laser light emitting device, 33 laser light emitting device, 34 laser light emitting device, 40 substrate (first substrate), 40a front surface, 40b rear surface, 40c side surface, 41 wiring, 43 Wiring (signal line), 43a specific transmission section, 44 wiring, 51 laser light source, 52 modulation section, 61 condenser lens, 62 condenser lens, 63 condenser lens, 64 condenser lens, 70 fiber array, 71 optical system, 72 optical fiber, 231 laser light emitting device, 241 wiring, 243 wiring (signal line), 243a specific transmission section, 243b specific transmission section, 361 collimator lens (parallel light conversion section), 362 collimator lens (parallel light conversion section), 363 collimator lens (parallel light conversion section), 364 collimator lens (parallel light conversion section), 365 condenser lens, 366 condenser lens, 367 condenser lens, 368 condenser lens, 370 fiber array, 371 optical system, D1 direction (predetermined direction), R1 termination resistor, W1 Wiring, W2 wiring, W3 wiring, W31 connection, W4 wiring (wire), W41 connection, W5 wiring.

Claims

1. A substrate; a laser light source that is held on a surface of the substrate and that generates a laser light; a modulation unit that is held on a surface of the substrate and that modulates the laser light generated by the laser light source and emits the modulated laser light in a predetermined direction from one end of the substrate in the predetermined direction along the surface of the substrate; a signal line formed on a surface of the substrate, for transmitting a modulation signal for modulating the laser light generated by the laser light source to the modulation unit; The signal line is disposed at a position closer to the one end of the substrate than to the other end, and the modulation signal is input from the one side.

1. A laser beam emitting device comprising:

2. The modulation section and the signal line are disposed closer to the one end than to the center of the substrate in the predetermined direction.

2. The laser beam emitting device according to claim 1.

3. The signal line is formed on the front surface and the back surface of the substrate.

2. The laser beam emitting device according to claim 1.

4. The signal line is formed on a front surface, a side surface, and a rear surface of the substrate.

4. The laser beam emitting device according to claim 3.

5. The signal line has a specific transmission portion that transmits the modulated signal in a direction opposite to the predetermined direction.

2. The laser beam emitting device according to claim 1.

6. a wire connecting the modulation unit and the signal line; The signal line transmits the modulated signal to the modulation unit via the wire.

2. The laser beam emitting device according to claim 1.

7. the substrate is a first substrate, A second substrate; a laser beam emitting device according to claim 1 , which is held by the second substrate; a modulation signal output unit that is held on the second substrate and outputs the modulation signal that modulates the laser light generated by the laser light source. An optical module comprising:

8. The modulation signal output unit is held on a surface of the second substrate opposite to a surface that holds the laser beam emitting device.

8. The optical module according to claim 7.

9. The modulation signal output unit is held on a surface of the second substrate that holds the laser beam emitting device, and is disposed forward of the laser beam emitting device in the predetermined direction.

8. The optical module according to claim 7.

10. a parallel light conversion unit that is held on a surface of the second substrate that holds the laser light emission device and is disposed forward of the laser light emission device in the predetermined direction, and that converts the laser light emitted from the laser light emission device into parallel light, The modulated signal output unit is disposed forward of the parallel light conversion unit in the predetermined direction.

10. The optical module according to claim 9.

11. The modulation signal output unit is held on a surface of the second substrate that holds the laser beam emitting device, and is disposed behind the laser beam emitting device in the predetermined direction.

8. The optical module according to claim 7.

12. The modulation signal output section is electrically connected to the laser beam emitting device via wiring formed on a surface of the second substrate opposite to a surface that holds the laser beam emitting device.

12. The optical module according to claim 11.

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