Optical module and method for manufacturing optical module

Abstract

This optical module (100, 200) is provided with: a package (40); a carrier (1) housed in the package (40); a semiconductor laser device (2) disposed on the carrier (1); a lens (3) that converts the laser beam (15) emitted from the semiconductor laser device (2) into parallel light; a beam splitter (4) that splits the laser beam (15) that has passed through the lens (3) into a first laser beam (20a) that is emitted to the outside and a second laser beam (20b) that is reflected to the inside; a first light-receiving element (5) having a reflective film (30) formed on a light-receiving surface, receiving a portion of the second laser beam (20b), and reflecting a remaining portion (20c) of the second laser beam; an etalon (6) that selects the wavelength of the remainder (20c) of the incident second laser beam; and a second light receiving element (7) that receives the laser beam having the wavelength selected by the etalon (6).

Description

Technical Field

[0001] This disclosure relates to optical modules and methods for manufacturing optical modules. Background Technology

[0002] With the popularization of the Internet, the capacity of optical communication systems is being increased. As a high-capacity optical communication system, dense wavelength division multiplexing (DWDM) transmission method, which multiplexes optical signals at a predetermined wavelength interval, and digital coherent method, which carries information in phase in addition to intensity modulation and carries multiple pieces of information for a single modulator, have been introduced.

[0003] In DWDM, to reduce signal filtering loss and crosstalk between channels, the wavelength of the light source needs to be precisely controlled to match a preset wavelength. Similarly, in digital coherent transmission, the transmitted and received optical signals also need to match the wavelength of the local light source to prevent interference; therefore, the wavelength of the light source also needs to be precisely controlled to match a preset wavelength.

[0004] On the other hand, semiconductor laser devices (Laser Diodes: LDs), which serve as the light source in optical communication systems, have the characteristic that the wavelength of the emitted laser beam varies depending on factors such as ambient temperature and drive current. Therefore, a wavelength monitor is built into the optical module to monitor the oscillation wavelength of the laser beam emitted by the LD, thereby controlling the wavelength with high precision.

[0005] In the light source device described in Patent Document 1, the laser beam emitted by the LD is branched to the monitor PD1 side and the monitor PD2 side by a beam splitter. The light output of the laser beam emitted by the LD is monitored on the monitor PD1 side, and a preamplifier of the monitor PD2 side is installed on the monitor PD2 side. The oscillation wavelength of the LD is monitored by a standard for selecting the wavelength of the incident laser beam, thereby controlling the light output and oscillation wavelength of the laser beam emitted by the LD.

[0006] Patent Document 1: Japanese Patent No. 4255611

[0007] In high-capacity optical communication systems, small and low-cost optical modules are required. CAN-type optical modules using TO-CAN offer advantages in miniaturization and cost reduction due to the fewer optical components and excellent mass production capabilities. However, the internal space of the CAN package is limited, making it difficult to ensure mounting space for optical components such as wavelength monitors. In particular, the internal space perpendicular to the optical axis needs to be smaller than the lead pins of the electrical interface of the CAN package, resulting in a mounting space of only about 2mm in diameter within the CAN package. Furthermore, while the CAN package does not have the same vertical limitations in the optical axis direction, a shorter dimension along the optical axis is still desirable.

[0008] In the light source device described in Patent Document 1, an optical system is provided that branches the light in a direction perpendicular to the emitted light and directs the branched light to two photodetectors respectively. Therefore, there is a problem that the wavelength monitor becomes larger and it is difficult to miniaturize the device. Summary of the Invention

[0009] This disclosure is made to solve the aforementioned problems, with the aim of obtaining a miniaturized optical module with a built-in wavelength monitor and a method for manufacturing the optical module.

[0010] The optical module disclosed herein has the following features:

[0011] Packaging:

[0012] Carrier, which is housed in the package;

[0013] A semiconductor laser device disposed on the carrier;

[0014] A lens that converts the laser beam emitted from the semiconductor laser device into parallel light;

[0015] A beam splitter that branches the laser beam after passing through the lens into a first laser beam that is emitted outward and a second laser beam that is reflected inward;

[0016] The first light-receiving element has a reflective film formed on its light-receiving surface, which receives a portion of the second laser beam and reflects the remainder of the second laser beam;

[0017] An etalon, which selects the wavelength of the remaining portion of the incident second laser beam; and

[0018] The second light-receiving element receives a laser beam of wavelength selected by the etalon.

[0019] The optical module manufacturing method disclosed herein includes the following steps:

[0020] The process of placing a semiconductor laser device at a predetermined position on a carrier;

[0021] The process of placing a lens on the carrier at the position where the laser beam emitted from the semiconductor laser device is incident;

[0022] The process of placing a beam splitter on the carrier and adjusting the angle of the beam splitter relative to the laser beam, wherein the beam splitter emits a portion of the laser beam converted into parallel light by the lens as a first laser beam outward and reflects the remaining portion of the laser beam as a second laser beam inward;

[0023] On the carrier, a process is performed in which a first light-receiving element with a reflective film formed on its light-receiving surface is positioned to receive a portion of the second laser beam and to reflect the remaining portion of the second laser beam, and the angle of the first light-receiving element relative to the incident second laser beam is adjusted.

[0024] The process of placing a standard on the carrier at the position where the remaining portion of the second laser beam is incident, and selecting the wavelength of the remaining portion of the incident second laser beam using the standard; and

[0025] The process of placing a second light-receiving element on the carrier to receive a laser beam of wavelength selected by the etalon.

[0026] According to the optical module and the manufacturing method of the optical module disclosed herein, since a light-receiving element is provided that has a reflective film formed on the light-receiving surface, receives a portion of the incident laser beam, and reflects the remainder of the laser beam, a miniaturized optical module with a built-in wavelength monitor is achieved, and the miniaturized optical module can be easily manufactured. Attached Figure Description

[0027] Figure 1 This is a structural diagram showing the structure of the optical module in Embodiment 1 from the side.

[0028] Figure 2 This is a structural diagram showing the structure of the optical module in Embodiment 1 from the top surface direction.

[0029] Figure 3 This is a cross-sectional view of the light-receiving element, which is part of the structure of the optical module in Embodiment 1.

[0030] Figure 4 This is a schematic diagram of the CAN package used in the optical module of Embodiment 1.

[0031] Figure 5 This is a graph showing the wavelength dependence of transmittance of a standard.

[0032] Figure 6 It is magnification Figure 5 A diagram showing the range of A.

[0033] Figure 7 It means Figure 6 A graph showing the relationship between the etalon incident angle along the X-axis and the etalon incident angle along the Y-axis at point B.

[0034] Figure 8 This is a structural diagram showing the structure of the optical module in Embodiment 2 from the side.

[0035] Figure 9This is a structural diagram showing the structure of the optical module in Embodiment 2 from the top surface direction.

[0036] Figure 10 This is a diagram illustrating the manufacturing process of the optical module manufacturing method in Embodiment 3.

[0037] Figure 11 This is a graph showing the relationship between coupling loss and angular deviation in the optical modules of embodiments 1 and 2.

[0038] Figure 12 This is an enlarged view of the lens portion of the optical module in embodiments 1 and 2. Detailed Implementation

[0039] Implementation method 1.

[0040] <Structure of the optical module in Implementation Method 1>

[0041] Figure 1 This is a structural diagram showing the optical module 100 of Embodiment 1 from the side view. Additionally, Figure 2 This is a structural diagram showing the optical module 100 of Embodiment 1 from the top surface direction.

[0042] like Figure 1 As shown, the optical module 100 includes: a CAN package 40 (not shown); a carrier 1 housed in the CAN package 40; a semiconductor laser device 2 disposed on the carrier 1 via a sub-support 2a; a lens 3 that converts a laser beam 15 emitted from the semiconductor laser device 2 into parallel light; a beam splitter 4 that branches the laser beam 15 transmitted through the lens 3 into a first laser beam 20a emitted outward and a second laser beam 20b reflected inward; a first light-receiving element 5 having a reflective film 30 formed on its light-receiving surface, receiving a portion of the second laser beam 20b and reflecting the remaining portion 20c of the second laser beam; a datum plate 6 that selects the wavelength of the remaining portion 20c of the incident second laser beam; a second light-receiving element 7 that receives a laser beam of the wavelength selected by the datum plate 6; a temperature control device 8 that controls the temperature of the semiconductor laser device 2 on the carrier 1; a base 9 that mounts the carrier 1 and the temperature control device 8 on its surface side; and a plurality of lead pins 10 that stand upright from the back side of the base 9.

[0043] The semiconductor laser device 2 is configured such that its center is located on the central axis 12 of the carrier 1 along the light emission direction. Similarly, the lens 3 is configured such that its center is located on the central axis 12 of the carrier 1. Figure 2As shown in the top view, the center of the semiconductor laser device 2 is substantially aligned with the central axis 12a, which is parallel to the surface of the base 9. However, the center of the semiconductor laser device 2 and the center of the lens 3 do not need to be strictly aligned with the central axis 12 of the carrier 1; they can be approximately aligned.

[0044] Figure 3 This is a cross-sectional view of the first light-receiving element 5. A reflective film 30 is formed on the light-receiving surface of the first light-receiving element 5. The reflectivity of the reflective film 30 is preferably 30% or more and 70% or less, but more preferably 40% or more and 60% or less. The first light-receiving element 5 receives a portion of the second laser beam 20b incident on it, i.e., the laser beam that passes through the reflective film 30, and converts it into a signal current as a photocurrent. In addition, the first light-receiving element 5 reflects the remaining portion 20c of the second laser beam in the direction of incident on the standard etalon 6 through the reflective film 30 formed on the light-receiving surface. The first light-receiving element 5 is disposed at a mounting portion 5a, which is provided on the surface of the carrier 1.

[0045] The etalon 6 selects the wavelength of the remaining portion 20c of the incident second laser beam. The laser beam with the wavelength selected by the etalon 6 is received by the second light-receiving element 7. The second light-receiving element 7 functions as a wavelength monitor. As an example of the first light-receiving element 5 and the second light-receiving element 7, a photodiode (PD) can be cited.

[0046] Figure 4 This is a schematic diagram of the CAN package 40 used in the optical module 100 of Embodiment 1. As an example, the package used in the optical module 100 can be listed below. Figure 4 The CAN package 40 is shown. An optical fiber 41 is installed at the front end of the CAN package 40. The package used for the optical module 100 can also be a package other than the CAN package 40, such as a BOX type package.

[0047] <Operation of the optical module in Implementation Method 1>

[0048] The operation of the optical module 100 in Embodiment 1 will be described below.

[0049] The laser beam 15 emitted from the semiconductor laser device 2 is converted into parallel light by the lens 3 and incident on the beam splitter 4 arranged in the optical path. A reflective structure consisting of a reflective film that reflects a portion, for example, a few percent, of the light is formed on the incident surface of the beam splitter 4, and a non-reflective structure, i.e., an AR coating, is formed on the exit surface. The first laser beam 20a, which is not reflected by the beam splitter 4 and passes through, is focused onto the optical fiber 41 by a lens (not shown) formed on the cover of the CAN package 40. The first laser beam 20a output to the optical fiber 41 serves as the light source for the optical communication system.

[0050] On the other hand, the second laser beam 20b, which is branched approximately at a right angle by the beam splitter 4, is incident on the first light-receiving element 5 disposed in the optical path. That is, by using the beam splitter 4 to branch a portion of the laser beam 15 emitted from the semiconductor laser device 2, a branched beam, namely the second laser beam 20b, is obtained with a deflection of approximately 90°. As described above, on the light-receiving surface of the first light-receiving element 5, for example, a reflective structure is formed that reflects approximately half of the incident laser beam, that is, approximately 50% of the laser beam, i.e., a reflective film 30 with a reflectivity of approximately 50%.

[0051] In the second laser beam 20b, the laser beam that is not reflected by the light-receiving surface of the first light-receiving element 5 is absorbed within the first light-receiving element 5, and a signal current corresponding to the light output of the received laser beam, i.e., the photocurrent, flows. The photocurrent of the first light-receiving element 5 reflects the light output of the laser beam 15 emitted from the semiconductor laser device 2, and therefore can be used to keep the light output of the laser beam 15 of the semiconductor laser device 2 constant.

[0052] On the other hand, the remaining portion 20c of the second laser beam reflected by the reflective film 30 on the light-receiving surface of the first light-receiving element 5 is received by the second light-receiving element 7 through the standard 6. At this time, the standard 6 selects the wavelength of the remaining portion 20c of the incident second laser beam.

[0053] That is, by deflecting the remaining portion of the second laser beam 20b incident on the first light-receiving element 5 as the remaining portion 20c of the second laser beam by about 90°, a portion of the laser beam 15 emitted from the semiconductor laser device 2 is refracted back through the beam splitter 4 and the first light-receiving element 5 and incident on the etalon 6, so that the laser beam with the selected wavelength passing through the etalon 6 is transmitted and received by the second light-receiving element 7.

[0054] Figure 5 This is a graph showing the wavelength dependence of the transmittance of the standard 6. Figure 6 This is an amplified representation of the wavelength dependence of the etalon's transmittance. Figure 5 The diagram showing the range of A. Furthermore, in Figure 5 as well as Figure 6 In this context, the wavelength is shown as the angle of incidence towards the etalon. Additionally, Figure 7 It means Figure 6 A graph showing the relationship between the etalon incident angle in the axial direction and the etalon incident angle in the Y-axis direction at point B.

[0055] like Figure 5 as well as Figure 6As shown, the transmittance of the etalon 6 represents the characteristic of repetitive peaks and valleys relative to the wavelength of the laser beam. For example, if the wavelength of the semiconductor laser device 2, which serves as the light source, is to be set to λ0, the temperature of the semiconductor laser device 2 is adjusted by the temperature control device 8 to make the transmittance of the etalon T0, thereby maintaining the wavelength of the semiconductor laser device 2 at λ0.

[0056] The light output of the semiconductor laser device 2 may vary over time. In such cases, even if the temperature of the semiconductor laser device 2 is adjusted to keep the photocurrent of the second photoreceiving element 7 constant, the wavelength of the laser beam 15 may not be constant at λ0, and wavelength shift may occur. To prevent wavelength shift, the transmittance is calculated by dividing the current value of the photocurrent detected by the first photoreceiving element 5 (i.e., the current value corresponding to the light output of the laser beam 15 emitted from the semiconductor laser device 2) by the current value of the photocurrent detected by the second photoreceiving element 7. The temperature of the semiconductor laser device 2 is then controlled by the temperature control device 8 to keep the transmittance value constant.

[0057] <Effects of Implementation Method 1>

[0058] According to the optical module of Embodiment 1, since the light-receiving surface of the first light-receiving element has a reflective structure, it receives a portion of the laser beam incident on the first light-receiving element and reflects the remaining portion of the incident laser beam. Therefore, it is not necessary to construct an additional optical system for detecting the light output of the semiconductor laser device, thus achieving the effect of miniaturization of the optical module that realizes the built-in wavelength monitor.

[0059] Furthermore, a portion of the laser beam emitted from the semiconductor laser device is branched and deflected by approximately 90° by a beam splitter, and the branched light is further deflected by approximately 90° by the first light-receiving element. This causes the laser beam emitted from the semiconductor laser device to be refracted back and incident on the etalon, thereby achieving miniaturization of the second light-receiving element. In particular, it enables a reduction in the lateral width of the carrier along the direction parallel to the surface of the base and a reduction in the length of the carrier along the optical axis of the optical module, thus further achieving the effect of miniaturizing the optical module with a built-in wavelength monitor.

[0060] Implementation method 2.

[0061] <Structure of the optical module in Implementation Method 2>

[0062] Figure 8 This is a structural diagram showing the optical module 200 of Embodiment 2 from the side view. Additionally, Figure 9 This is a structural diagram of the optical module 200 of Embodiment 2, viewed from the top surface direction.

[0063] The optical components constituting the optical module 200 of Embodiment 2 are the same as those constituting the optical module 100 of Embodiment 1, but the configuration of the optical module 100 of Embodiment 1, the semiconductor laser device 2, and the lens 3 are different. That is, the semiconductor laser device 2 is positioned at a predetermined offset distance from the central axis 12a of the light emission direction from the carrier 1 along a direction parallel to the surface of the base 9, that is, along the vertical direction of the central axis 12a toward the end side of the carrier 1.

[0064] Furthermore, the lens 3 is positioned offset from the semiconductor laser device 2, which is positioned at an offset location, along the opposite direction toward the central axis 12a of the carrier 1, i.e., offset by a predetermined reverse offset distance. Moreover, the central axis 12a of the light emission direction from the carrier 1, along the direction parallel to the surface of the base 9, refers to the direction from... Figure 9 The direction indicated by the central axis 12b in the diagram.

[0065] The reasons for positioning the semiconductor laser device 2 in the offset direction and positioning the lens 3 in the opposite offset direction relative to the semiconductor laser device 2 are explained below.

[0066] In the optical fiber 41 into which the first laser beam 20a is emitted from the semiconductor laser device 2, the incident surface of the optical fiber 41 is polished at an angle relative to the optical axis of the optical fiber 41 to prevent reflections from the incident surface of the optical fiber 41 back to the semiconductor laser device 2. This is because, in order for the first laser beam 20a to be efficiently coupled to the angled polished optical fiber 41, the laser beam needs to be incident from an angle relative to the optical axis of the optical fiber 41.

[0067] The laser beam 15 emitted from the semiconductor laser device 2, positioned in the offset direction, is focused by the lens 3, positioned in the opposite offset direction. During focusing, the laser beam 15 is oriented by the lens 3, which is positioned in the opposite offset direction, and its direction is changed to a constant angle from the central axis 12a of the carrier 1. Therefore, the first laser beam 20a, passing through the beam splitter 4, is emitted to the outside along the angled direction from the central axis 12a of the carrier 1. As a result, the first laser beam 20a can be efficiently coupled to the tilted and polished optical fiber 41.

[0068] Furthermore, on the carrier 1, the semiconductor laser device 2 is arranged in the offset direction and the lens 3 is arranged in the reverse offset direction, so that the mounting space of the etalon 6 can be ensured to be wider compared with the case of Embodiment 1.

[0069] <Effects of Implementation Method 2>

[0070] According to the optical module of embodiment 2, since the semiconductor laser device is arranged in the offset direction and the lens is arranged in the reverse offset direction, the laser beam emitted from the semiconductor laser device can be efficiently coupled to the tilted polished optical fiber, which can further ensure the installation space of the etalon. Therefore, it can achieve the effect of a smaller optical module with a built-in wavelength monitor.

[0071] Implementation method 3.

[0072] The manufacturing method of the optical module in Embodiment 3 is the same as the manufacturing method of the optical modules 100 and 200 in Embodiments 1 and 2. Figure 10 This is a diagram illustrating the manufacturing process of the optical module manufacturing method according to Embodiment 3. The manufacturing method of the optical module according to Embodiment 3 will be described below.

[0073] <Method for Manufacturing an Optical Module in Embodiment 3>

[0074] In the optical component configuration process S101, the semiconductor laser device 2, beam splitter 4, first light-receiving element 5, standard 6 and second light-receiving element 7 are respectively arranged on the carrier 1 at predetermined positions in such a way that the incident surface of the standard 6 with the orientation adjustment angle is approximately parallel to the mounting surface of the lens 3.

[0075] If we further describe the optical component arrangement process S101 in detail, the optical component arrangement process S101 is configured to include the following steps: a step of arranging the semiconductor laser device 2 at a predetermined position on the carrier 1; a step of arranging the lens 3 on the carrier 1 at the position where the laser beam 15 emitted from the semiconductor laser device 2 is incident; a step of arranging a beam splitter 4 on the carrier 1, which emits a portion of the laser beam 15 converted into parallel light by the lens 3 as a first laser beam 20a to the outside and reflects the remaining portion of the laser beam 15 as a second laser beam 20b to the inside; and adjusting the angle of the beam splitter 4 relative to the laser beam 15. The process includes: a process of adjusting the angle of the first light-receiving element 5 relative to the incident second laser beam 20b by placing a first light-receiving element 5, on the carrier 1, on a position where a first light-receiving element 5 with a reflective film 30 formed on its light-receiving surface is positioned to receive a portion of the second laser beam 20b and to reflect the remaining portion 20c of the second laser beam; a process of placing a standard 6 on the carrier 1 at the position where the remaining portion 20c of the second laser beam is incident, and selecting the wavelength of the remaining portion 20c of the incident second laser beam by the standard 6; and a process of placing a second light-receiving element 7, which receives the laser beam of the wavelength selected by the standard 6, on the carrier 1.

[0076] In the oscillation wavelength and current control process S102 of the semiconductor laser device, the temperature of the semiconductor laser device 2 is controlled by the temperature control device 8 to make the laser beam 15 emitted from the semiconductor laser device 2 have a preset oscillation wavelength and light output mode, and the driving current driving the semiconductor laser device 2 is controlled.

[0077] In the lens optical axis direction adjustment process S103, the position of the optical axis direction of the lens 3 is adjusted in such a way that the laser beam 15 emitted from the semiconductor laser device 2 is converted into parallel light.

[0078] In the lens parallel direction adjustment process S104, the lens 3 is further moved in a direction perpendicular to the optical axis and in a direction parallel to the mounting surface, and adjusted and fixed in such a way that the photocurrent of the second light-receiving element 7 becomes a preset current value.

[0079] After the above processes, the optical module is completed.

[0080] <Effects of the manufacturing method of the optical module in Embodiment 3>

[0081] The effects of the optical module manufacturing method of Embodiment 3 will be described below.

[0082] (1) First effect

[0083] As a first effect of the manufacturing method of the optical module in Embodiment 3, the effect of being able to adjust the transmittance of the etalon 6 by a small change in the incident angle toward the etalon 6, that is, a small amount of lens displacement.

[0084] The semiconductor laser device 2, beam splitter 4, first light-receiving element 5, standard 6, and second light-receiving element 7 are respectively positioned and adjusted at predetermined angles on the carrier 1 so that the incident surface of the etalon 6 is approximately parallel to the mounting surface of the lens 3. Figure 5 As shown, the transmission characteristics of the standard etalon 6 can be adjusted by a small change in the incident angle of the laser beam.

[0085] For example, in amplifying the representation standard, the transmittance is wavelength dependent. Figure 5 The range of A Figure 6 In the case of point B, which is represented by a circle, the angle of incidence toward the etalon 6 will be changed by about ±0.3°, thereby changing the transmittance of the etalon by one cycle.

[0086] Furthermore, if the focal length of lens 3 is assumed to be 500 μm, which is typical for semiconductor laser devices, then the lens displacement that results in a ±0.3° change in the emitted beam is 2.6 μm. That is, the transmittance of the etalon can be adjusted by a very small amount of lens displacement.

[0087] Furthermore, although the angle of the emitted light changes when the incident angle of lens 3 to etalon 6 is adjusted, it is based on... Figure 11 The coupling loss calculated from the angle deviation shown shows that if the angle of the emitted light changes within ±0.3°, the coupling loss to the optical fiber is about 0.01dB, which is extremely small and will hardly affect the angle of the emitted light.

[0088] (2) Second effect

[0089] As a second effect of the manufacturing method of the optical module in Embodiment 3, the effect of minimal influence of axial offset during lens fixing can be cited.

[0090] As mentioned above, on the one hand, the transmittance of the etalon can be adjusted with a very small amount of lens displacement; on the other hand, there is concern about the effect of axial offset from the self-aligning position on the fixed lens 3. Figure 12 As shown in the enlarged view of the lens portion, the lens 3 is generally fixed to the carrier 1 using adhesive 32. However, due to the effects of heating during the curing of adhesive 32, the expansion of adhesive 32 caused by heat, and the shrinkage caused by the curing of adhesive 32 after bonding, axial misalignment of the lens 3 may occur. Furthermore, due to the symmetry of the lens bonding structure, this misalignment is almost negligible. Figure 12 The axial offset of lens 3 in the X-axis direction is mainly generated in the Y-axis direction.

[0091] As mentioned above, in Figure 7 The results shown are obtained by calculating the dependence of the etalon incident angles in the X-axis and Y-axis directions on the etalon transmittance. As an example, consider the case where the axial offset of lens 3 is 0.9 μm when it is fixed. Furthermore, the 0.9 μm axial offset of lens 3 is 0.1° when converted into a change in the incident angle toward etalon 6.

[0092] Depend on Figure 7 It can be seen that, in the X-axis direction where the incident angle toward the etalon 6 has been adjusted, a change of 0.1° in the incident angle will cause a large change in the transmittance of the etalon. On the other hand, for the angular deviation in the Y-axis direction that occurs when the lens is fixed, even if the incident angle toward the etalon 6 in the Y-axis direction changes by 0.1°, the transmittance of the etalon will not change significantly.

[0093] As described above, by setting the angle of incidence of lens 3 to the etalon to be perpendicular to the optical axis and parallel to the lens mounting surface, optical modules 100 and 200 with built-in wavelength monitors can be easily manufactured without being affected by axial offset when the lens is fixed.

[0094] Furthermore, although the lens position along the Y-axis may change over time, the research results above indicate that the transmittance of the etalon does not easily change even when it changes over time. This means that the optical modules 100 and 200 of embodiments 1 and 2 also exhibit excellent reliability.

[0095] (3) Third effect

[0096] As a third effect of the optical module manufacturing method of Embodiment 3, the assembly of the optical modules of Embodiments 1 and 2 is easy to adjust.

[0097] In conventional manufacturing methods for built-in optical modules in wavelength monitors, the lens is aligned and fixed relative to the semiconductor laser device. After adjusting and fixing the position and angle of the beam splitter so that the light emitted from the lens can be received by the monitor PD, the angle is adjusted while the etalon is rotated to observe the photocurrent received by the monitor PD.

[0098] On the other hand, in the manufacturing method of the optical module in Embodiment 3, the beam splitter 4 is installed at a predetermined position and a predetermined angle without being aligned, i.e., passively installed. The adjustment of the incident angle to the etalon 6 is also performed simultaneously when the lens is aligned, thus achieving the effect of easy assembly of the optical modules 100 and 200.

[0099] When the standard 6 is rotated and adjusted and then mounted, the temperature of the standard 6 being maintained may not be the same as the temperature of the carrier 1, which is also mounted on the semiconductor laser device 2 and whose wavelength is adjusted to a preset value by the temperature control device 8. Therefore, even if the standard 6 is rotated and adjusted, there is a possibility that the transmittance of the standard 6 may change after it is mounted on the carrier 1.

[0100] In order to address the potential defects that may occur when adding a standard 6 in conventional optical module manufacturing methods, in the optical module manufacturing method of Embodiment 3, the standard 6 is pre-mounted on the carrier 1. Therefore, the temperature of the standard 6 becomes the same as the temperature of the semiconductor laser device 2 when adjusting the wavelength, i.e., the temperature of the carrier 1. Thus, no defect of change in the transmittance of the standard 6 occurs after assembly.

[0101] The above is an explanation of the effects of the optical module manufacturing method of Embodiment 3.

[0102] Furthermore, although the CAN package 40 is described as one form of package in this disclosure, the package of the optical module applied to this disclosure is not limited to the form of the CAN package 40. For example, the same effect can be obtained even if it is applied to a BOX type package.

[0103] Although this disclosure describes various exemplary embodiments and examples, the various features, forms and functions described in one or more embodiments are not limited to the application of a particular embodiment, and can be applied to the embodiments alone or in various combinations.

[0104] Therefore, numerous variations not illustrated can be conceived within the scope of the technology disclosed in the specification. For example, these include variations, additions, or omissions of at least one constituent element, as well as cases where at least one constituent element is extracted and combined with constituent elements of other embodiments.

[0105] Explanation of reference numerals in the attached figures

[0106] 1...carrier; 2...semiconductor laser device; 2a...sub-support; 3...lens; 4...beam splitter; 5...first light-receiving element; 5a...mounting position; 6...etalon; 7...second light-receiving element; 8...temperature control device; 9...base; 10...lead pins; 12, 12a, 12b...central axis; 15...laser beam; 20a...first laser beam; 20b...second laser beam; 20c...remaining portion of the second laser beam; 30...reflective film; 32...adhesive; 40...CAN package; 41...optical fiber; 100, 200...optical module.

Claims

1. An optical module, characterized in that, have: Packaging: Carrier, which is housed in the package; A semiconductor laser device disposed on the carrier; A lens that converts the laser beam emitted from the semiconductor laser device into parallel light; A beam splitter that branches the laser beam after passing through the lens into a first laser beam that is emitted outward and a second laser beam that is reflected inward; The first light-receiving element has a reflective film formed on its light-receiving surface, which receives a portion of the second laser beam and reflects the remainder of the second laser beam; A etalon, which selects the wavelength of the remaining portion of the incident second laser beam; as well as The second light-receiving element receives a laser beam of wavelength selected by the etalon.

2. The optical module according to claim 1, characterized in that, The semiconductor laser device is positioned at a location offset by a predetermined offset distance along the vertical direction of the central axis of the light emission direction from the carrier.

3. The optical module according to claim 2, characterized in that, The lens is positioned at a location offset from the semiconductor laser device by a predetermined reverse offset distance toward the central axis.

4. The optical module according to any one of claims 1 to 3, characterized in that, The reflective film has a reflectivity of 30% or more and 70% or less.

5. The optical module according to any one of claims 1 to 3, characterized in that, The reflective film has a reflectivity of 40% or more and 60% or less.

6. The optical module according to any one of claims 1 to 5, characterized in that, The packaging is either CAN packaging or BOX-type packaging.

7. A method for manufacturing an optical module, characterized in that, It includes the following processes: The process of placing a semiconductor laser device at a predetermined position on a carrier; The process of placing a lens on the carrier at the position where the laser beam emitted from the semiconductor laser device is incident; The process of placing a beam splitter on the carrier and adjusting the angle of the beam splitter relative to the laser beam, wherein the beam splitter emits a portion of the laser beam converted into parallel light by the lens as a first laser beam outward and reflects the remaining portion of the laser beam as a second laser beam inward; On the carrier, a process is performed in which a first light-receiving element with a reflective film formed on its light-receiving surface is positioned to receive a portion of the second laser beam and to reflect the remaining portion of the second laser beam, and the angle of the first light-receiving element relative to the incident second laser beam is adjusted. The process of placing a standard on the carrier at the position where the remaining portion of the second laser beam is incident, and selecting the wavelength of the remaining portion of the incident second laser beam using the standard; as well as The process of placing a second light-receiving element on the carrier to receive a laser beam of wavelength selected by the etalon.

8. The method for manufacturing an optical module according to claim 7, characterized in that, It also includes a process for controlling the temperature and drive current of the semiconductor laser device to make the laser beam emitted from the semiconductor laser device have a preset wavelength and light output.

9. The method for manufacturing an optical module according to claim 7 or 8, characterized in that, In the process of setting the lens, the position of the optical axis of the lens is adjusted in such a way that the laser beam emitted from the semiconductor laser device is converted into parallel light, thereby moving the lens in a direction perpendicular to the optical axis and in a direction parallel to the mounting surface, thereby adjusting the photocurrent of the second light-receiving element to a preset current value.

10. The method for manufacturing an optical module according to claim 7 or 8, characterized in that, When the semiconductor laser device is positioned on the carrier, the semiconductor laser device is positioned at a position offset by a predetermined offset distance along the vertical direction of the central axis of the light emission direction from the carrier.

11. The method for manufacturing an optical module according to claim 10, characterized in that, When the lens is positioned on the carrier, it is positioned at a position offset from the semiconductor laser device toward the central axis by a predetermined reverse offset distance.

Images