Optical device, light source module and manufacturing method thereof, and optical engine

Abstract

Optical device, light source module and manufacturing method thereof, and optical engine. Monitoring light is stably obtained in a sufficient amount. The optical device has a light function layer on a substrate. The light function layer has a light branching portion (120a, 120b, 120c) branching visible light emitted from each visible laser light source (301a, 301b, 301c), a monitoring light waveguide (130a, 130b, 130c) connected to an output portion of one of each light branching portion, and a modulation light waveguide (140a, 140b, 140c) connected to an output portion of the other of each light branching portion. Monitoring light propagating in the monitoring light waveguide is emitted from a monitoring port (131a, 131b, 131c). Display light propagating in the modulation light waveguide is combined by a light combining portion (180) after being modulated by a light modulation portion (170a, 170b, 170c), and is emitted from a light output port (191).

Description

Technical Field

[0001] This disclosure relates to optical devices, light source modules and methods for manufacturing the same, and optical engines. Background Technology

[0002] In recent years, XR glasses, such as AR (Augmented Reality) glasses and VR (Virtual Reality) glasses, have attracted attention as small wearable devices. Regarding XR glasses, it is important to miniaturize the various structural elements to fit within the typical size of eyeglasses. In particular, retinal scanning displays are expected to visually confirm images by imaging two-dimensionally scanned light onto the user's retina. In such retinal scanning displays, light sources such as LEDs (Light Emitting Diodes) and LDs (Laser Diodes) corresponding to the colors R (red), G (green), and B (blue) are generally used. Visible light of each color emitted from the various light sources is combined and transmitted to the image display unit. The image display unit scans the transmitted light in two dimensions and directs this light into the user's pupil. This incident light forms an image on the user's retina, allowing the user to visually confirm the image.

[0003] Color representation in XR glasses and similar devices is achieved using visible light of each of the RGB colors. When adjusting the color balance of each RGB color, the incident light branch corresponding to that color is used as a monitoring light. By checking the intensity of the monitoring light, the color balance of each color can be adjusted.

[0004] Patent Document 1 discloses an optical wave combiner that can be connected to or integrated with an optical modulator using a lithium niobate film, and that can adjust the RGB color balance. The optical wave combiner disclosed in Patent Document 1 comprises multiple multimode interference optical wave combiners (first to third optical wave combiners), and visible light modulated by a Mach-Zehnder type optical modulator is input to each optical wave combiner. The first optical wave combiner is connected to a first optical input waveguide, a first monitoring optical output waveguide, and a first connecting waveguide. The second optical wave combiner is connected to a second optical input waveguide, a first connecting waveguide, a second monitoring optical output waveguide, and a second connecting waveguide. The third optical wave combiner is connected to a third optical input waveguide, a second connecting waveguide, a third monitoring optical output waveguide, and an optical output port connecting waveguide. The first monitoring light output waveguide to the third monitoring light output waveguide are all configured not to cross with other light waveguides, in order to prevent light output loss (crossing loss).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2024-94959 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] The optical wave combiner disclosed in Patent Document 1 is a structure in which an optical wave combiner is connected to the post-stage of a Mach-Zehnder type optical modulator. The visible light modulated by the optical modulator is split in the optical wave combiner and then output from the monitoring light output port (monitoring port) through the optical waveguide on the monitoring light output side.

[0010] However, in order to obtain a sufficient amount of monitoring light from the monitoring light output port, the intensity of the visible light modulated by the light modulator needs to be high. If the light intensity is insufficient, there is a problem that not enough light can be obtained from the monitoring light output port, thus affecting the measurement accuracy.

[0011] When using Mach-Zehnder type optical modulators, the light intensity may decrease due to the initial phase difference generated between the two optical waveguides. This phase difference depends on the initial settings in the unvoltage state; to ensure sufficient light intensity, an appropriate voltage needs to be applied. In particular, when inputting a visible light laser source into the optical input port and using light from the monitoring optical output port for active alignment, appropriate voltages need to be applied to each optical modulator used to propagate each visible light beam. Therefore, there is a problem of increased complexity and decreased efficiency in the active alignment process.

[0012] This disclosure was made in view of the above-mentioned problems, and its purpose is to provide an optical device, a light source module and a method for manufacturing the same, as well as an optical engine, capable of stably obtaining a sufficient amount of monitoring light from a monitoring port.

[0013] Solution for solving the problem

[0014] To address the aforementioned problems, the optical device disclosed herein comprises a substrate and an optical functional layer formed on the main surface of the substrate. The optical device is characterized in that the optical functional layer comprises: an optical input port corresponding to each of a plurality of visible light laser sources, capable of receiving visible light emitted from each visible light laser source; an input optical waveguide connected to each optical input port; an optical branch having an input portion connected to each input optical waveguide and two output portions; a monitoring optical waveguide connected to one output portion of each optical branch; a monitoring port connected to each monitoring optical waveguide for emitting monitoring light to the outside; a first optical waveguide connected to the other output portion of each optical branch; an optical modulation section connected to each first optical waveguide; a second optical waveguide connected to each optical modulation section; an optical combining section connected to each second optical waveguide; an output optical waveguide connected to the optical combining section; and an optical output port connected to the output optical waveguide for emitting light combined by the optical combining section to the outside.

[0015] To address the aforementioned issues, the light source module disclosed herein is characterized by having the aforementioned optical devices and the plurality of visible light laser light sources.

[0016] To solve the above problems, the manufacturing method of the light source module disclosed herein is a method for manufacturing the aforementioned light source module. The manufacturing method is characterized in that visible light emitted from the visible light laser source is incident on the light input port, and light emitted from the monitoring port is incident on an optical detection device. Based on the detection result of the optical detection device, the relative position of the visible light laser source with respect to the optical device is adjusted, and the visible light laser source is fixed relative to the optical device at a position in which the optical axis of the visible light emitted from the visible light laser source coincides with the center position of the light input port.

[0017] To solve the above problems, the optical engine disclosed herein is characterized by comprising: the aforementioned light source module; and a light scanning mirror that changes angle to reflect light emitted from the light source module for image display.

[0018] The effects of the invention

[0019] This disclosure provides an optical device, a light source module, a method for manufacturing the same, and an optical engine capable of stably obtaining sufficient light from a monitoring port. Attached Figure Description

[0020] Figure 1 This is a top view of the light source module in the first embodiment of this disclosure.

[0021] Figure 2 It shows from Figure 1The top view of the light source module without the electrodes and pads is shown.

[0022] Figure 3 It is along Figure 1 A cross-sectional view along line AA.

[0023] Figure 4 It is along Figure 1 A cross-sectional view of the BB line.

[0024] Figure 5 It is along Figure 1 A cross-sectional view of the CC line.

[0025] Figure 6 yes Figure 1 and Figure 2 A top view of the conical section.

[0026] Figure 7 yes Figure 1 and Figure 2 A top view of the cross waveguide in the diagram.

[0027] Figure 8 yes Figure 1 and Figure 2 A top view of the connected cross waveguides.

[0028] Figure 9 yes Figure 1 and Figure 2 A top view of a high-order mode filter.

[0029] Figure 10 This is a diagram illustrating the active alignment performed during the manufacturing process of the light source module in the first embodiment of this disclosure.

[0030] Figure 11 This is a diagram used to illustrate the concept of active alignment performed in the first embodiment of this disclosure.

[0031] Figure 12 This diagram illustrates the state in which an anti-reflective device is arranged near the monitoring port of the light source module in the first embodiment of this disclosure.

[0032] Figure 13 This is a concept diagram of the optical engine and XR glasses in the first embodiment of this disclosure.

[0033] Figure 14 This is a top view schematic diagram of the light source module in a derivative example of the first embodiment of this disclosure.

[0034] Figure 15 It shows from Figure 14 The top view of the light source module without the electrodes and pads is shown.

[0035] Figure 16 This is a top view of the light source module in the second embodiment of this disclosure.

[0036] Figure 17 It shows from Figure 16 The top view of the light source module without the electrodes and pads is shown.

[0037] Figure 18 This is a top view schematic diagram of the light source module in a derivative example of the second embodiment of this disclosure.

[0038] Figure 19 It shows from Figure 18 The top view of the light source module without the electrodes and pads is shown.

[0039] Figure 20 This is a top view of the light source module in the third embodiment of this disclosure.

[0040] Figure 21 It shows from Figure 20 The top view of the light source module without the electrodes and pads is shown.

[0041] Figure 22 This is a top view of the light source module in the fourth embodiment of this disclosure.

[0042] Figure 23 It shows from Figure 22 The top view of the light source module without the electrodes and pads is shown. Detailed Implementation

[0043] Hereinafter, embodiments of the present disclosure will be described in detail with appropriate reference to the accompanying drawings. In the drawings used in the following description, for ease of understanding, characteristic parts are sometimes shown enlarged for convenience, and the dimensions, proportions, etc., of each structural element may differ from the actual dimensions. The materials, dimensions, etc., illustrated in the following description are merely examples. The present disclosure is not limited to such examples and can be implemented with appropriate modifications within the scope of achieving the effects of the present disclosure. Furthermore, the "~" indicating a numerical range refers to any value within a range that includes the lower and upper limits of the values ​​stated before and after it.

[0044] [First Implementation Method]

[0045] The first embodiment of this disclosure will now be described.

[0046] <Light Source Module>

[0047] Reference Figure 1 and Figure 2 The structure of the light source module 1A in the first embodiment of this disclosure will be described. Figure 1 This is a top view of the light source module 1A in the first embodiment. Figure 2 It shows from Figure 1 A top view of the light source module 1A with the electrodes 200 and pads 201 removed.

[0048] like Figure 1 and Figure 2 As shown, the light source module 1A has multiple visible light laser light sources 301a, 301b, 301c and optical device 10A.

[0049] In this specification, in the XYZ orthogonal coordinate system set in the figure, the direction along one side of the optical device 10A is defined as the X direction, the direction orthogonal to the X direction is defined as the Y direction, and the direction orthogonal to both the X and Y directions is defined as the Z direction. The X direction is consistent with the light incident direction from the plurality of visible light laser sources 301a, 301b, and 301c onto the optical device 10A. The Y direction is the width direction of the optical device 10A. The Z direction is the direction perpendicular to the main surface of the optical device 10A. Hereinafter, the orientation will be further considered as "positive Z direction," "negative Z direction," etc. In particular, the "positive Z direction" is sometimes referred to as the upward direction, and the "negative Z direction" is sometimes referred to as the downward direction. Furthermore, the Z direction, as the upward and downward direction, may not be consistent with the direction of gravity.

[0050] Visible Light Laser Sources

[0051] Multiple visible light laser sources 301a, 301b, and 301c are configured to emit visible light (laser) in different wavelength regions, for example. Visible light laser source 301a is a light source that emits laser light of a specific color. Although not particularly limited, laser diodes (LDs) or laser light-emitting diodes can be used, for example.

[0052] Visible light laser sources 301a, 301b, and 301c emit visible light in the three primary colors (red, green, and blue), respectively. By using the principle of additive color mixing to make these emitted lights overlap, the desired color can be represented. Visible light laser sources 301a, 301b, and 301c can also emit light in colors other than the three primary colors.

[0053] In light source module 1A, visible light laser source 301a emits red light, visible light laser source 301b emits green light, and visible light laser source 301c emits blue light. Visible light laser source 301a, for example, is a red laser source emitting laser light (red light) in the wavelength region of 590nm to 800nm. Visible light laser source 301b, for example, is a green laser source emitting laser light (green light) in the wavelength region of 490nm and above but less than 590nm. Visible light laser source 301c, for example, is a blue laser source emitting laser light (blue light) in the wavelength region of 380nm and above but less than 490nm. There is no particular limitation on the arrangement order or number of visible light laser sources 301a, 301b, and 301c emitting light in each wavelength region.

[0054] Multiple visible light laser sources 301a, 301b, and 301c are fixed relative to the optical device 10A. The visible light laser sources 301a, 301b, and 301c can also be mounted as bare chips on the upper surfaces of the sub-carriers 302a, 302b, and 302c. In this case, the sub-carriers 302a, 302b, and 302c are aligned with the substrate 101 of the optical device 10A (see reference 101). Figures 3-5 The metal bonding layer and other bonding parts 303a, 303b, and 303c are joined together.

[0055] To ensure that the lasers emitted from visible light laser sources 301a, 301b, and 301c are properly incident on the optical input ports 110a, 110b, and 110c of the optical device 10A, optical axis adjustment is required. Figure 1 In the light source module 1A shown, as described later, the optical axes of the visible light laser light sources 301a, 301b, and 301c can be adjusted based on the monitoring light emitted from the monitoring ports 131a, 131b, and 131c.

[0056] <Optical Devices>

[0057] Optical device 10A has a planar structure in which optical waveguides are formed two-dimensionally on substrate 101. For example... Figure 1 and Figure 2 As shown, the optical device 10A has four end faces located on the side, namely the first end face 11, the second end face 12, the third end face 13 and the fourth end face 14.

[0058] The first end face 11 is a light incident surface equipped with light input ports 110a, 110b, and 110c. The second end face 12 is a surface substantially parallel to the first end face 11 and located on the opposite side of the first end face 11. Figure 1 and Figure 2In the optical device 10A shown, monitoring ports 131a, 131b, and 131c are arranged on the second end face 12. The third end face 13 is a surface substantially perpendicular to the first end face 11 and the second end face 12, and is located on the left side (positive Y-direction side) when viewed from the first end face 11. The fourth end face 14 is a surface substantially perpendicular to the first end face 11 and the second end face 12, and is located on the right side (negative Y-direction side) when viewed from the first end face 11. Figure 1 and Figure 2 In the optical device 10A shown, an optical output port 191 is arranged on the fourth end face 14.

[0059] An optical waveguide for propagating light is formed in the optical device 10A. The optical waveguide of the optical device 10A is designed to propagate the laser emitted from the visible light laser sources 301a, 301b, and 301c, and to exit from the monitoring ports 131a, 131b, and 131c and the optical output port 191.

[0060] like Figure 1 As shown, an electrode 200 is disposed on the upper surface (main surface) side of the optical device 10A. The electrode 200 is used to apply a driving voltage for modulating light, and is suitably disposed near the light modulation sections 170a, 170b, and 170c. The electrode 200 has pad portions 201 near the third end face 13 and the fourth end face 14. The pad portions 201 function as connection terminals for electrically connecting the voltage supply circuit. The construction of the electrode 200 is not particularly limited. Furthermore, although not shown in the figure, an electrode for applying a bias voltage may also be disposed, for example.

[0061] The structure of the optical device 10A in this embodiment will be described below.

[0062] An optical waveguide for propagating laser light emitted from visible light laser source 301a will be described. An optical input port 110a is disposed on the first end face 11. The optical input port 110a is the optical input port for the laser light emitted from visible light laser source 301a. The laser light emitted from visible light laser source 301a is incident on the optical input port 110a.

[0063] An input optical waveguide 111a is connected to the optical input port 110a. One end of the input optical waveguide 111a is connected to the optical input port 110a. The other end of the input optical waveguide 111a is connected to the optical input section of the optical branch 120a.

[0064] The optical branch section 120a has a one-input, two-output structure with one optical input section and two optical output sections, configured to split a single optical input signal into two optical output signals. The optical branch section 120a can be used to split light propagating in an optical waveguide without any particular limitation, and can use, for example, an MMI coupler (multimode interference coupler), a Y-branch (Y-type waveguide), a directional coupler, etc.

[0065] One optical output section of the optical branch 120a is connected to one end of the monitoring optical waveguide 130a. The monitoring optical waveguide 130a bends midway and extends along the Y direction, and extends along the X direction near the third end face 13. The other end of the monitoring optical waveguide 130a is connected to a monitoring port 131a disposed on the second end face 12. The monitoring port 131a is a monitoring light output port used to monitor the laser emitted from the visible light laser source 301a. In this specification, the light output from the optical branch 120a to the monitoring optical waveguide 130a is sometimes referred to as monitoring light.

[0066] A tapered portion 135a for changing the width (waveguide width) of the optical waveguide is disposed midway through the monitoring optical waveguide 130a. Regarding the tapered portion 135a, refer to... Figure 6 The details will be described later.

[0067] Another light output section of the light branch 120a is connected to one end of the modulation optical waveguide 140a. The other end of the modulation optical waveguide 140a is connected to the light input section of the high-order mode filter 150a. In this specification, the light output from the light branch 120a to the modulation optical waveguide 140a is sometimes referred to as display light. The display light output from the light branch 120a is red light, which, after being modulated by the light modulation section 170a, is combined with display light of other wavelengths to be used, for example, as image projection light for XR glasses.

[0068] A cross waveguide 160a, which intersects with the monitoring optical waveguide 130b, and a cross waveguide 160b, which intersects with the monitoring optical waveguide 130c, are arranged in the modulation optical waveguide 140a. For details regarding cross waveguides 160a and 160b, refer to... Figure 8 The details will be described later.

[0069] The high-order mode filter 150a includes an optical input section and an optical output section, and is configured to remove high-order modes of the light input to the optical input section, outputting only single-mode light from the optical output section. For more information on the high-order mode filter 150a, please refer to... Figure 9 The details will be described later.

[0070] The optical output section of the high-order mode filter 150a is connected to one end of the modulation optical waveguide 151a. The other end of the modulation optical waveguide 151a is connected to the optical input section of the optical modulation section 170a. The modulation optical waveguide 140a and the modulation optical waveguide 151a constitute the first optical waveguide of this disclosure. In this disclosure, the optical branch section 120a is connected to the optical modulation section 170a via the first optical waveguide, and the optical branch section 120a is disposed in the pre-stage of the optical modulation section 170a.

[0071] The optical modulation unit 170a is configured to modulate the light input to the optical input unit and output the modulated light from the optical output unit. For example, the optical modulation unit 170a can use a Mach-Zehnder type optical waveguide with a Mach-Zehnder interferometer structure.

[0072] like Figure 2 As shown, the other end of the modulation optical waveguide 151a is connected to the optical branch section 171a, which serves as the optical input section of the optical modulation unit 170a. In the optical branch section 171a, the modulation optical waveguide 151a branches into two branch waveguides 172a and 173a. The two branch waveguides 172a and 173a extend parallel to each other along the X-direction and are connected to the optical combining section 174a, which serves as the optical output section of the optical modulation unit 170a. The two branch waveguides 172a and 173a merge in the optical combining section 174a.

[0073] The optical modulation unit 170a controls the voltage supplied to the electrode 200 to apply an electric field to the branch waveguides 172a and 173a. The application of the electric field causes changes in the refractive index of the branch waveguides 172a and 173a, respectively, and modulates the phase of the light based on these changes in refractive index. The optical modulation unit 170a utilizes the interference effect to adjust the amplitude of the light after it has been combined by the optical combining unit 174a, outputting light of the desired intensity.

[0074] One end of the modulation optical waveguide 175a is connected to the optical output section of the optical modulation section 170a. The other end of the modulation optical waveguide 175a is connected to the optical input section of the optical combining section 180. The modulation optical waveguide 175a constitutes the second optical waveguide of this disclosure.

[0075] The optical combining section 180 has a multi-input, one-output structure with at least two optical input sections and one optical output section, configured to combine two or more optical input signals into a single optical output signal. Figure 1 and Figure 2 In the optical device 10A shown, the optical wave combiner 180 has a three-input, one-output structure, configured to combine light input from modulation optical waveguide 175a, modulation optical waveguide 175b, and modulation optical waveguide 175c. However, the optical wave combiner 180 is not limited to this structure; for example, a two-input, one-output optical wave combiner can be multi-stage connected.

[0076] The optical wave combiner 180 can combine light propagating in the optical waveguide without any particular limitation. For example, it can use an MMI coupler (multimode interference coupler), a Y-branch (Y-type waveguide), a directional coupler, etc.

[0077] One end of the output optical waveguide 181 is connected to the optical output section of the optical wave combiner 180. The output optical waveguide 181 is bent approximately vertically at the bend 182. The other end of the output optical waveguide 181 is connected to the optical output port 191 disposed on the fourth end face 14. The optical output port 191 is a light output port for outputting the light combined by the optical wave combiner 180, and the light output from the optical output port 191 is emitted to the outside.

[0078] An optical waveguide for propagating laser light emitted from visible light laser source 301b will be described. An optical input port 110b is disposed on the first end face 11. The optical input port 110b is the optical input port for the laser light emitted from visible light laser source 301b. The laser light emitted from visible light laser source 301b is incident on the optical input port 110b.

[0079] An input optical waveguide 111b is connected to the optical input port 110b. One end of the input optical waveguide 111b is connected to the optical input port 110b. The other end of the input optical waveguide 111b is connected to the optical input section of the optical branch 120b.

[0080] The optical branch 120b has a one-input, two-output structure with one optical input and two optical outputs, configured to split a single optical input signal into two optical output signals. The optical branch 120b can be used to split light propagating in an optical waveguide without any particular limitation; for example, it can use an MMI coupler (multimode interference coupler), a Y-branch (Y-type waveguide), a directional coupler, etc.

[0081] One optical output section of the optical branch 120b is connected to one end of the monitoring optical waveguide 130b. The monitoring optical waveguide 130b bends midway and extends along the Y direction, and extends along the X direction near the third end face 13. The other end of the monitoring optical waveguide 130b is connected to a monitoring port 131b disposed on the second end face 12. The monitoring port 131b is a monitoring light output port used to monitor the laser emitted from the visible light laser source 301b. In this specification, the light output from the optical branch 120b to the monitoring optical waveguide 130b is sometimes referred to as monitoring light.

[0082] A tapered portion 135b for changing the waveguide width is disposed midway through the monitoring optical waveguide 130b. Regarding the tapered portion 135b, refer to... Figure 6 This will be described later. In addition, a cross waveguide 160a is arranged in the monitoring optical waveguide 130b, which intersects with the modulation optical waveguide 140a.

[0083] Another light output section of the light branch 120b is connected to one end of the modulation optical waveguide 140b. The other end of the modulation optical waveguide 140b is connected to the light input section of the high-order mode filter 150b. In this specification, the light output from the light branch 120b to the modulation optical waveguide 140b is sometimes referred to as display light. The display light output from the light branch 120b is green light, which, after being modulated by the light modulation section 170b, is combined with display light of other wavelengths to be used, for example, as image projection light for XR glasses.

[0084] A cross waveguide 160c, which intersects with the monitoring optical waveguide 130c, is disposed in the modulation optical waveguide 140b. For details regarding the cross waveguide 160c, refer to... Figure 7 The details will be described later.

[0085] The high-order mode filter 150b includes an optical input section and an optical output section, configured to remove high-order modes of the light input to the optical input section and output only single-mode light from the optical output section. For more information on the high-order mode filter 150b, please refer to... Figure 9 The details will be described later.

[0086] The optical output section of the high-order mode filter 150b is connected to one end of the modulation optical waveguide 151b. The other end of the modulation optical waveguide 151b is connected to the optical input section of the optical modulation section 170b. The modulation optical waveguide 140b and the modulation optical waveguide 151b constitute the first optical waveguide of this disclosure. In this disclosure, the optical branch section 120b and the optical modulation section 170b are connected via the first optical waveguide, and the optical branch section 120b is disposed in the pre-stage of the optical modulation section 170b.

[0087] The optical modulation unit 170b is configured to modulate the light input to the optical input unit and output the modulated light from the optical output unit. For example, the optical modulation unit 170b can use a Mach-Zehnder type optical waveguide with a Mach-Zehnder interferometer structure.

[0088] like Figure 2 As shown, the other end of the modulation optical waveguide 151b is connected to the optical branch section 171b, which serves as the optical input section of the optical modulation unit 170b. In the optical branch section 171b, the modulation optical waveguide 151b branches into two branch waveguides 172b and 173b. The two branch waveguides 172b and 173b extend parallel to each other along the X-direction and are connected to the optical combining section 174b, which serves as the optical output section of the optical modulation unit 170b. The two branch waveguides 172b and 173b merge in the optical combining section 174b.

[0089] The optical modulation unit 170b controls the voltage supplied to the electrode 200 to apply an electric field to the branch waveguides 172b and 173b. The application of the electric field causes changes in the refractive index of the branch waveguides 172b and 173b, and the phase of the light is modulated based on these changes in refractive index. The optical modulation unit 170b utilizes the interference effect to adjust the amplitude of the light after it has been combined by the optical combining unit 174b, outputting light of the desired intensity.

[0090] One end of the modulation optical waveguide 175b is connected to the optical output section of the optical modulation section 170b. The other end of the modulation optical waveguide 175b is connected to the optical input section of the optical combining section 180. The modulation optical waveguide 175b constitutes the second optical waveguide of this disclosure.

[0091] As described above, the optical wave combiner 180 combines the light input from the modulation optical waveguide 175a, modulation optical waveguide 175b, and modulation optical waveguide 175c. The light combined by the optical wave combiner 180 is emitted to the outside from the optical output port 191 through the output optical waveguide 181.

[0092] An optical waveguide for propagating laser light emitted from a visible light laser source 301c will be described. An optical input port 110c is disposed on the first end face 11. The optical input port 110c is the optical input port for the laser light emitted from the visible light laser source 301c. The laser light emitted from the visible light laser source 301c is incident on the optical input port 110c.

[0093] An input optical waveguide 111c is connected to the optical input port 110c. One end of the input optical waveguide 111c is connected to the optical input port 110c. The other end of the input optical waveguide 111c is connected to the optical input section of the optical branch 120c.

[0094] The optical branch section 120c has a one-input, two-output structure with one optical input section and two optical output sections, configured to split a single optical input signal into two optical output signals. The optical branch section 120c can be used to split light propagating in an optical waveguide without any particular limitation, and can use, for example, an MMI coupler (multimode interference coupler), a Y-branch (Y-type waveguide), a directional coupler, etc.

[0095] One optical output section of the optical branch 120c is connected to one end of the monitoring optical waveguide 130c. The monitoring optical waveguide 130c bends midway and extends along the Y direction, and extends along the X direction near the third end face 13. The other end of the monitoring optical waveguide 130c is connected to a monitoring port 131c disposed on the second end face 12. The monitoring port 131c is a monitoring light output port used to monitor the laser emitted from the visible light laser source 301c. In this specification, the light output from the optical branch 120c to the monitoring optical waveguide 130c is sometimes referred to as monitoring light.

[0096] A tapered portion 135c for changing the waveguide width is disposed midway through the monitoring optical waveguide 130c. Regarding the tapered portion 135c, refer to... Figure 6 This will be described later. In addition, the monitoring optical waveguide 130c is provided with a cross waveguide 160c that intersects with the modulation optical waveguide 140b, and a cross waveguide 160b that intersects with the modulation optical waveguide 140a.

[0097] Another light output section of the light branch 120c is connected to one end of the modulation optical waveguide 140c. The other end of the modulation optical waveguide 140c is connected to the light input section of the high-order mode filter 150c. In this specification, the light output from the light branch 120c to the modulation optical waveguide 140c is sometimes referred to as display light. The display light output from the light branch 120c is blue light, which, after being modulated by the light modulation section 170c, is combined with display light of other wavelengths to be used, for example, as image projection light for XR glasses.

[0098] The high-order mode filter 150c includes an optical input section and an optical output section, configured to remove high-order modes of the light input to the optical input section and output only single-mode light from the optical output section. For more information on the high-order mode filter 150c, please refer to... Figure 9 The details will be described later.

[0099] The optical output section of the high-order mode filter 150c is connected to one end of the modulation optical waveguide 151c. The other end of the modulation optical waveguide 151c is connected to the optical input section of the optical modulation section 170c. The modulation optical waveguide 140c and the modulation optical waveguide 151c constitute the first optical waveguide of this disclosure. In this disclosure, the optical branch section 120c is connected to the optical modulation section 170c via the first optical waveguide, and the optical branch section 120c is disposed in the pre-stage of the optical modulation section 170c.

[0100] The optical modulation unit 170c is configured to modulate the light input to the optical input unit and output the modulated light from the optical output unit. For example, the optical modulation unit 170c can use a Mach-Zehnder type optical waveguide with a Mach-Zehnder interferometer structure.

[0101] like Figure 2 As shown, the other end of the modulation optical waveguide 151c is connected to the optical branch section 171c, which serves as the optical input section of the optical modulation unit 170c. In the optical branch section 171c, the modulation optical waveguide 151c branches into two branch waveguides 172c and 173c. The two branch waveguides 172c and 173c extend in parallel along the X-direction and are connected to the optical combining section 174c, which serves as the optical output section of the optical modulation unit 170c. In the optical combining section 174c, the two branch waveguides 172c and 173c merge with the modulation optical waveguide 151c.

[0102] The optical modulation unit 170c controls the voltage supplied to the electrode 200 to apply an electric field to the branch waveguides 172c and 173c. The application of the electric field causes changes in the refractive index of the branch waveguides 172c and 173c, and the phase of the light is modulated based on these changes in refractive index. The optical modulation unit 170c utilizes the interference effect to adjust the amplitude of the light after it has been combined by the optical combining unit 174c, outputting light of the desired intensity.

[0103] One end of the modulation optical waveguide 175c is connected to the optical output section of the optical modulation section 170c. The other end of the modulation optical waveguide 175c is connected to the optical input section of the optical combining section 180. The modulation optical waveguide 175c constitutes the second optical waveguide of this disclosure.

[0104] As described above, the optical wave combiner 180 combines the light input from the modulation optical waveguide 175a, modulation optical waveguide 175b, and modulation optical waveguide 175c. The light combined by the optical wave combiner 180 is emitted to the outside from the optical output port 191 through the output optical waveguide 181.

[0105] exist Figure 1 and Figure 2 In the optical device 10A, optical input ports 110a, 110b, and 110c are arranged at equal intervals along the Y direction on the first end face 11, but their intervals may not be equal. In addition, a portion of the optical input ports 110a, 110b, and 110c may also be arranged on different end faces of the optical device 10A.

[0106] exist Figure 1 and Figure 2 In this design, monitoring optical waveguides 130a, 130b, and 130c extend near the third end face 13, but may also extend near the fourth end face 14. Additionally, monitoring ports 131a, 131b, and 131c can also be configured on either the third end face 13 or the fourth end face 14. Furthermore, a portion of monitoring ports 131a, 131b, and 131c can also be configured on different end faces of the optical device 10A. Figure 1 and Figure 2 In this case, the optical output port 191 is configured on the fourth end face 14, but it can also be configured on other end faces (such as the second end face 12) as described in the derivative examples below.

[0107] <Cross-sectional structure of optical devices>

[0108] Reference Figures 3-5 To illustrate the cross-sectional structure of the optical device 10A. Figure 3 It is along Figure 1 A cross-sectional view along line AA. Figure 4 It is along Figure 1 A cross-sectional view of the BB line. Figure 5 It is along Figure 1A cross-sectional view of the CC line.

[0109] like Figures 3-5 As shown, the optical device 10A has a substrate 101, an optical functional layer 102, and a protective layer 106. The optical functional layer 102 is, for example, composed of an optical waveguide layer 103, a first buffer layer 104, and a second buffer layer 105. The optical device 10A has a multilayer structure obtained by sequentially stacking the optical waveguide layer 103, the first buffer layer 104, the second buffer layer 105, and the protective layer 106 on the substrate 101.

[0110] like Figure 3 and Figure 5 As shown, the electrode 200 and the pad portion 201 are disposed between the second buffer layer 105 and the protective layer 106. Figure 3 In the figure, the driving electrode 200S and the reference electrode 200G are illustrated as electrodes 200.

[0111] The substrate 101 is a component used to ensure the overall physical stability and durability of the optical device 10A. From the viewpoint of improving light propagation efficiency by enclosing light in the optical waveguide formed in the optical functional layer 102, the material of the substrate 101 is preferably a material with a lower refractive index than the material of the optical waveguide layer 103. As the substrate 101, for example, a substrate made of a material containing aluminum oxide (sapphire substrate), a Si substrate, a thermally oxidized silicon substrate, etc., can be used.

[0112] The optical waveguide layer 103 functions as a waveguide core film for forming the optical waveguide. The optical waveguide layer 103 is a ferroelectric thin film composed of a crystal represented by the chemical formula ABX3. Materials exhibiting electro-optic effects can be used for the optical waveguide layer 103. Examples of materials exhibiting electro-optic effects include oxide ferroelectrics such as lithium niobate (LiNbO3), lithium tantalate (LiTaO3), and barium titanate (BaTiO3). Optical devices 10A using lithium niobate in the optical waveguide layer 103 are sometimes referred to as LN optical devices, and optical modulators equipped with LN optical devices are sometimes referred to as LN optical modulators.

[0113] When a sapphire single-crystal substrate or a silicon single-crystal substrate is used as the substrate 101, the lithium niobate film constituting the optical waveguide layer 103 can be formed as an epitaxial film on the upper surface of the substrate 101. The crystal orientation of the substrate 101 is not particularly limited, but since it serves as the substrate of the optical waveguide layer 103, it is preferable to have the same symmetry as the optical waveguide layer 103. Specifically, the lithium niobate film has a three-dimensional symmetry. When using a c-axis oriented lithium niobate film as the optical waveguide layer 103, if it is a sapphire single-crystal substrate, it is preferable to use a substrate 101 with the c-plane, and if it is a silicon single-crystal substrate, it is preferable to use a substrate 101 with the (111) plane.

[0114] An epitaxial film refers to a film obtained by growing a crystal based on the crystal orientation of a substrate 101 that serves as the substrate, and by having a specific crystal orientation consistent with the crystal structure of the substrate 101. Whether the optical waveguide layer 103 is an epitaxial film relative to the substrate 101 can be demonstrated, for example, by performing peak intensity and pole analysis at the orientation position in 2θ-θ X-ray diffraction.

[0115] Specifically, when performing measurements based on 2θ-θ X-ray diffraction, the intensity of all peaks except the target plane should be 10% or less, preferably 5% or less, of the maximum peak intensity of the target plane. For example, in the case of an epitaxial film composed of a c-axis oriented lithium niobate film, the peak intensity except for the (00L) plane should be 10% or less, preferably 5% or less, of the maximum peak intensity of the (00L) plane. Here, (00L) is a general term for planes such as (001), (002), etc.

[0116] Furthermore, poles also need to be observed in pole analysis. Confirming the peak intensity at a specific orientation position only evaluates the crystal orientation in one direction. Therefore, even if the peak intensity can be confirmed to be below a specified value, the X-ray intensity will not increase at a specific angular position and poles will not be observed if the in-plane crystal orientation is inconsistent. LiNbO3 has a trigonal crystal structure; therefore, there are three poles in a single crystal of LiNbO3(014).

[0117] In the case of lithium niobate films, it is known that a crystal rotated 180° around the c-axis is epitaxially grown in a so-called bicrystalline state with symmetrical coupling. In this case, two parts are symmetrically coupled with three poles, thus six poles are observed. In addition, when a lithium niobate film is formed on a silicon single-crystal substrate with the (100) plane, since the substrate is four-fold symmetric, 4 × 3 = 12 poles are observed. Furthermore, in this disclosure, lithium niobate films epitaxially grown in a bicrystalline state are also included in the epitaxial film.

[0118] The composition of lithium niobate is Li x NbA y O z x is 0.5~1.2, preferably 0.9~1.05. y is 0~0.5. z is 1.5~4.0, preferably 2.5~3.5. A is an element other than Li, Nb, and O. Examples of elements that can be used as A include K, Na, Rb, Cs, Be, Mg, Ca, Sr, Ba, Ti, Zr, Hf, V, Cr, Mo, W, Fe, Co, Ni, Zn, Sc, Ce, etc., or combinations of two or more of these elements.

[0119] The optical waveguide layer 103 is not limited to being formed by epitaxial growth, but can also be a thin film attached to the upper surface of the substrate 101.

[0120] The optical waveguide layer 103 is configured to have: a slab layer 103a having a specified thickness; and a ridge 103b protruding from the upper surface of the slab layer 103a. For example... Figure 3 and Figure 4 As shown, the ridge 103b is positioned to form an optical waveguide. The ridge 103b forms an optical waveguide that encloses light within itself for light propagation. Figure 3 The ridge 103b shown forms branch waveguides 172c and 173c. Figure 4 The ridge 103b shown forms a monitoring optical waveguide 130c. Figure 5 The cross-section does not have a ridge 103b, and the optical waveguide layer 103 is composed of a flat plate layer 103a with a specified thickness.

[0121] The ridge 103b can be a protrusion formed by etching the optical waveguide layer 103, or it can be formed by attaching the same material as the plate layer 103a to the upper surface of the plate layer 103a. The shape of the ridge 103b is not particularly limited, but it is formed here with a rectangular cross-section.

[0122] By making the distance between adjacent ridges 103b smaller, the electric field efficiency imparted to the optical waveguide formed by the ridges 103b can be improved.

[0123] Alternatively, an optical waveguide can be formed by creating a region with a high refractive index within the optical waveguide layer 103, instead of forming the optical waveguide from the ridge 103b. For example, a region with a high refractive index can be locally created within the optical waveguide layer 103 using Ti diffusion or proton exchange methods, and this region can be used as an optical waveguide.

[0124] like Figures 3-5 As shown, the first buffer layer 104 is disposed on the upper surface of the planar layer 103a of the optical waveguide layer 103. Near the formation location of the ridge 103b, the first buffer layer 104 is configured to fill between adjacent ridges 103b and cover the upper surface of the planar layer 103a and the side surface of the ridge 103b.

[0125] like Figures 3-5 As shown, the second buffer layer 105 is disposed on the upper surface of the first buffer layer 104. Near the formation location of the ridge 103b, the second buffer layer 105 is configured to cover the upper surface of the first buffer layer 104 and the upper surface of the ridge 103b.

[0126] The first buffer layer 104 and the second buffer layer 105 are made of a dielectric material with a refractive index lower than that of the optical waveguide layer 103. The first buffer layer 104 and the second buffer layer 105 serve to prevent visible light propagating in the optical waveguide layer 103 from being absorbed by the electrode 200.

[0127] Materials for the first buffer layer 104 and the second buffer layer 105 can include, for example, silicon oxide (SiO2), aluminum oxide (Al2O3), lanthanum oxide (La2O3), or composites of these oxides. Examples of composites of these oxides include LaAlSiInO. The materials for the first buffer layer 104 and the second buffer layer 105 can also be different. Here, as a preferred embodiment, silicon oxide is used as the material for the first buffer layer 104, and LaAlSiInO is used as the material for the second buffer layer 105. Alternatively, the materials for the first buffer layer 104 and the second buffer layer 105 can be the same, and the first buffer layer 104 and the second buffer layer 105 can also be configured as an integral unit.

[0128] like Figure 3 and Figure 5 As shown, electrode 200 and pad portion 201 are disposed on the upper surface of second buffer layer 105. In this embodiment, as an example, a structure using a Z-cut lithium niobate film as optical waveguide layer 103 is shown. In this case, since an electro-optic effect is strongly exhibited in the Z direction, therefore, as Figure 3 As shown, electrode 200 is preferably positioned directly above the ridge 103b forming the optical waveguide. However, an X-cut lithium niobate film can also be used as the optical waveguide layer 103. In this case, since an electro-optic effect is strongly exhibited in the Y direction, electrode 200 is preferably positioned to the side of the ridge 103b forming the optical waveguide.

[0129] like Figure 3 and Figure 4 As shown, the protective layer 106 is configured to cover the upper surface of the second buffer layer 105 and the upper surface of the electrode 200. The protective layer 106 protects the upper surface of the second buffer layer 105 and the upper surface of the electrode 200, particularly preventing damage to the electrode 200. For example, silicon oxide (SiO2) or silicon nitride (SiN) can be used as the material for the protective layer 106. The material of the protective layer 106 can be the same as or different from that of the first buffer layer 104 or the second buffer layer 105.

[0130] The protective layer 106 covers the entire upper surface of the optical device 10A, specifically the upper surface of the second buffer layer 105 and the upper surface of the electrode 200. However, as... Figure 5As shown, a portion of the pad portion 201 is not covered by the protective layer 106, and the upper surface 201a of the pad portion 201 is exposed to the outside. The pad portion 201 can be electrically connected to an external power supply circuit, etc., through the exposed upper surface 201a. Specifically, the protective layer 106 covers the entire side surface of the pad portion 201 and a portion of the upper surface 201a; however, the protective layer 106 is cut off at the upper surface 201a of the pad portion 201. As a result, a gap is formed between the ends 106a of the protective layer 106, and the upper surface 201a of the pad portion 201 is exposed to the outside through this gap. Alternatively, a metal layer may be formed on the upper part of the pad portion 201. This improves the strength of the physical connection with the external power supply circuit.

[0131] The height of the flat plate layer 103a ( Figures 3-5 The height H1 is not particularly limited, but is preferably 0.1 μm to 0.3 μm; for example, it is set to 0.15 μm. Regarding the ridge 103b, if it is too small, light cannot propagate properly; if it is too large, the propagated light becomes multimode. Therefore, it is preferable to set it to an appropriate size. The height from the lower surface of the flat plate layer 103a to the upper surface of the ridge 103b (H1) Figures 3-5 The height H2 is preferably 0.5 μm to 1.5 μm, and for example, it is set to 0.7 μm. The shape of the ridge 103b is not particularly limited, but it can be set to a base angle θ. Figure 3 and Figure 4 The angle θ) is a trapezoidal shape of 70°~90°.

[0132] The height of the second buffer layer 105 ( Figures 3-5 The height H3 is not particularly limited and can be set to the same level as the height H2 mentioned above. For example, it is set to 0.7 μm. The heights of the electrode 200 and the pad portion 201 (…) Figure 3 and Figure 5 The height H4 is not particularly limited, but is preferably 0.1 μm to 5.0 μm; for example, it is set to 2.0 μm. The height of the protective layer 106 ( Figures 3-5 The height (H5) is not particularly limited, but is preferably 0.5μm to 0.7μm.

[0133] The distance between the center positions of adjacent ridges 103b ( Figure 3 The width W1 is not particularly limited, but is preferably 2.0 μm to 12 μm; for example, it is set to 4.0 μm. The width of electrode 200 is not particularly limited, but the width of driving electrode 200S ( Figure 3 The width W2 is preferably 1.0 to 4.0 μm, and for example, it is set to 3.0 μm.

[0134] The distance between adjacent electrodes 200 is not particularly limited, and the distance between the sides of adjacent electrodes 200 is ( Figure 3 The width W4 is preferably 1.0 μm to 10 μm, and for example, it is set to 2.0 μm. The upper surface 201a of the pad portion 201 only needs to be exposed to the outside as an electrical connection terminal. For example, the distance between the end 106a of the protective layer 106 and the side of the pad portion 201 ( Figure 5 The width (W5) is set to 10μm.

[0135] The width of the ridge 103b is equivalent to the width of the optical waveguide. In this embodiment, the width of the ridge 103b forming the monitoring optical waveguides 130a, 130b, and 130c is set to be at least greater than the width of the ridge 103b forming the optical waveguides 170a, 170b, and 170c.

[0136] exist Figure 3 In the diagram, ridges 103b1 and 103b2, which form the branch waveguides 172c and 173c of the optical modulation section 170c, are shown as ridges 103b. The width WA of the upper surface of ridge 103b is shown in the reference diagram. Figure 3 For example, it is preferred to be 1.0 μm or less, and as an example, it is set to 0.8 μm. The width of the ridge 103b of the branch waveguides 172a and 173a forming the optical modulation section 170a, and the width of the ridge 103b of the branch waveguides 172b and 173b forming the optical modulation section 170b are also set in the same way.

[0137] exist Figure 4 In the diagram, a cross-section of the ridge 103b3 forming the monitoring optical waveguide 130c is shown, serving as ridge 103b. The width WB of the upper surface of the ridge 103b3 (see reference) Figure 4 For example, it is preferred to be 2.0 μm or more, and as an example, it is set to 3.0 μm. The width of the ridge 103b forming the monitoring optical waveguides 130a and 130b is also set in the same way.

[0138] The following is for reference Figure 2 A specific example of the waveguide width of the optical device 10A in this embodiment will be explained.

[0139] The waveguide widths of the input optical waveguides 111a, 111b, and 111c connected to the optical input ports 110a, 110b, and 110c are set to... Figure 3 The width WA is (e.g., 0.8 μm). In the optical branch sections 120a, 120b, and 120c, the optical waveguide branches are monitoring optical waveguides 130a, 130b, and 130c, and modulation optical waveguides 140a, 140b, and 140c.

[0140] The waveguide widths of the monitoring optical waveguides 130a, 130b, and 130c are modified within the tapered portion 135a. The width of the optical waveguide from the optical branches 120a, 120b, and 120c to the tapered portions 135a, 135b, and 135c is set as follows: Figure 3 The width WA is (e.g., 0.8 μm). In the tapered portions 135a, 135b, and 135c, the waveguide width increases towards the direction of light propagation. The width of the optical waveguide from the tapered portions 135a, 135b, and 135c to the monitoring ports 131a, 131b, and 131c is set to... Figure 4 The width WB (e.g., 3.0 μm).

[0141] As will be described later, the monitoring optical waveguides 130a, 130b, and 130c can also be configured such that the waveguide width varies within the cross waveguides 160a, 160b, and 160c. In the cross waveguides 160a, 160b, and 160c, the waveguide width of the monitoring optical waveguides 130a, 130b, and 130c is set to... Figure 4 The width WB (e.g., 3.0 μm) is greater than or equal to 3.0 μm.

[0142] The waveguide widths of modulation optical waveguides 140a, 140b, 140c and their subsequent stages are set to... Figure 3 The width WA is (e.g., 0.8 μm). More specifically, the waveguide widths of the modulation waveguides 140a, 140b, and 140c are set to... Figure 3 The width WA (e.g., 0.8 μm). The waveguide widths of the modulation optical waveguides 151a, 151b, and 151c are set to... Figure 3 The waveguide width WA (e.g., 0.8 μm). The waveguide widths of branch waveguides 172a, 173a, 172b, 173b, 172c, and 173c are set to... Figure 3 The width WA (e.g., 0.8 μm). The waveguide widths of the modulation optical waveguides 175a, 175b, and 175c are set to... Figure 3 The width WA (e.g., 0.8 μm). The waveguide width of the output optical waveguide 181 is set to... Figure 3 The width WA (e.g., 0.8 μm).

[0143] As described later, the modulation optical waveguides 140a, 140b, and 140c are configured such that their waveguide widths vary within the cross waveguides 160a, 160b, and 160c. Within the cross waveguides 160a, 160b, and 160c, the waveguide widths of the modulation optical waveguides 140a, 140b, and 140c are set to be greater than... Figure 3 The width WA (e.g., 0.8μm) is large.

[0144] In this way, by utilizing the tapered portions 135a, 135b, and 135c to extend the waveguide width of the monitoring optical waveguides 130a, 130b, and 130c to allow for multimode optical waves, the propagation loss caused by scattering and absorption can be reduced, thereby increasing the amount of light propagated. As a result, the output light quantity of the monitoring ports 131a, 131b, and 131c can be increased.

[0145] <Conical section>

[0146] Reference Figure 6 The tapered portions 135a, 135b, and 135c will now be explained. Figure 6 yes Figure 1 and Figure 2 A top view of the tapered portion 135a.

[0147] like Figure 6 As shown, the tapered portion 135a is disposed in the middle of the monitoring optical waveguide 130a, thereby changing the waveguide width of the monitoring optical waveguide 130a. The tapered portion 135a has a narrow end portion 135a1 located on the optical branch portion 120a side, a wide end portion 135a2 located on the monitoring port 131a side, and a widening portion 135a3 disposed between the narrow end portion 135a1 and the wide end portion 135a2.

[0148] The width of the narrow end 135a1 is the same as the width WA (e.g., 0.8 μm) of the optical waveguide from the optical branch 120a to the tapered portion 135a. The width of the wide end 135a2 is the same as the width WB (e.g., 3.0 μm) of the waveguide from the tapered portion 135a to the monitoring port 131a. The width of the widening portion 135a3 smoothly increases from the narrow end 135a1 toward the wide end 135a2. According to this structure, the tapered portion 135a smoothly extends the width of the monitoring optical waveguide 130a in the direction of propagation of the monitoring light.

[0149] The tapered portion 135a can be positioned anywhere on the monitoring optical waveguide 130a, but is preferably positioned near the optical branch portion 120a. The length L1 between the optical branch portion 120a and the narrow end portion 135a1 (refer to...) Figure 6 For example, a width of 50 μm to 500 μm is preferred. By arranging the tapered portion 135a near the optical branch portion 120a, the waveguide width can be made large in most areas of the monitoring optical waveguide 130a.

[0150] The length L2 of the widened portion 135a3 (refer to) Figure 6 The distance is preferably set to an appropriate value, taking into account the reduction of propagation loss and the efficiency of the manufacturing process. The length L2 of the widened portion 135a3 is not particularly limited, but is preferably 50 μm to 150 μm. For example, it is set to 100 μm.

[0151] Here, in Figure 6 The diagram illustrates the structure of the tapered portion 135a, but the tapered portions 135b and 135c also have the same structure.

[0152] By utilizing the tapered portions 135a, 135b, and 135c to expand the waveguide width of the monitoring optical waveguides 130a, 130b, and 130c, the monitoring light propagating in the monitoring optical waveguides 130a, 130b, and 130c is multimode-enabled. This reduces the propagation loss of the monitoring light in the monitoring optical waveguides 130a, 130b, and 130c, ensuring that a sufficient amount of monitoring light is emitted from the monitoring ports 131a, 131b, and 131c.

[0153] <Cross-waveguide>

[0154] Reference Figure 7 and Figure 8 Let's explain the cross waveguides 160a, 160b, and 160c. Figure 7 yes Figure 1 and Figure 2 A top view of the 160c cross waveguide. Figure 8 yes Figure 1 and Figure 2 A top view of the connected cross waveguides 160a, 160b, and 160c.

[0155] In the optical device 10A of this embodiment, monitoring optical waveguides 130a, 130b, and 130c extend along the Y direction midway to the vicinity of the third end face 13. According to this structure, intersections are formed between the monitoring optical waveguide 130b and the modulation optical waveguide 140a, between the monitoring optical waveguide 130c and the modulation optical waveguide 140a, and between the monitoring optical waveguide 130c and the modulation optical waveguide 140b.

[0156] At each intersection, propagation losses due to scattering and other factors increase, which may reduce the output light quantity of monitoring ports 131a, 131b, 131c and optical output port 191. Hereinafter, such losses will sometimes be referred to as "cross loss".

[0157] In the optical device 10A of this embodiment, considering the possible cross-loss in each cross section, cross waveguides 160a, 160b, and 160c are arranged in each cross section.

[0158] right Figure 7 The cross waveguide 160c shown is illustrated below. Figure 7As shown, a cross waveguide 160c is disposed at the intersection of the monitoring optical waveguide 130c and the modulation optical waveguide 140b, thereby changing the waveguide widths of the monitoring optical waveguide 130c and the modulation optical waveguide 140b respectively. In the intersection, it is preferable that the monitoring optical waveguide 130c and the modulation optical waveguide 140b intersect approximately perpendicularly to reduce the impact of cross-loss.

[0159] The cross waveguide 160c has four tapered sections 161c, 162c, 163c, 164c and a cross section 165c.

[0160] The tapered portion 161c constitutes part of an optical waveguide for propagating display light. The tapered portion 161c is disposed on the side of the optical branch portion 120b with reference to the intersection portion. The tapered portion 161c has a narrow end portion 161c1 located on the side of the optical branch portion 120b, a wide end portion 161c2 located on the side of the optical modulation portion 170b, and a widening portion 161c3 disposed between the narrow end portion 161c1 and the wide end portion 161c2.

[0161] The width of the narrow end 161c1 is the same as the width WA (e.g., 0.8 μm) of the modulation optical waveguide 140b. The width WC of the wide end 161c2 is set to be larger than the width WA of the narrow end 161c1. The width WC of the wide end 161c2 is preferably 2.0 μm to 5.0 μm, and for example, it is set to 3.6 μm.

[0162] The width of the widened portion 161c3 smoothly increases from the narrow end 161c1 toward the wide end 161c2. According to this structure, the tapered portion 161c smoothly extends the width of the modulation optical waveguide 140b in the direction of propagation of the display light.

[0163] The tapered portion 162c constitutes part of an optical waveguide for propagating display light. The tapered portion 162c is disposed on the side of the optical modulation portion 170b with reference to the intersection portion. The tapered portion 162c has a wide end portion 162c1 located on the side of the optical branch portion 120b, a narrow end portion 162c2 located on the side of the optical modulation portion 170b, and a narrowing portion 162c3 disposed between the wide end portion 162c1 and the narrow end portion 162c2.

[0164] The width of the wide end 162c1 is the same as the width WC of the wide end 161c2. The width of the narrow end 162c2 is the same as the width WA (e.g., 0.8 μm) of the modulation optical waveguide 140b. The width of the narrowing portion 162c3 smoothly decreases from the wide end 162c1 toward the narrow end 162c2. According to this structure, the tapered portion 162c smoothly reduces the width of the modulation optical waveguide 140b in the direction of propagation of the displayed light.

[0165] The length L3 of the widened portion 161c3 (refer to) Figure 7) and the length L4 of the narrowed portion 162c3 (refer to Figure 7 The lengths L3 and L4 of the widening portion 161c3 and the narrowing portion 162c3 are not particularly limited, but are preferably 50 μm to 150 μm. For example, both lengths L3 and L4 are set to 100 μm.

[0166] The tapered portion 163c constitutes part of an optical waveguide for propagating monitoring light. The tapered portion 163c is disposed on the side of the optical branch portion 120c with reference to the intersection portion. The tapered portion 163c has a narrow end portion 163c1 located on the side of the optical branch portion 120c, a wide end portion 163c2 located on the side of the monitoring port 131c, and a widening portion 163c3 disposed between the narrow end portion 163c1 and the wide end portion 163c2.

[0167] The width of the narrow end 163c1 is the same as the width WB of the monitoring optical waveguide 130c (e.g., 3.0 μm). The width WC of the wide end 163c2 is set to be greater than or equal to the width WB of the narrow end 163c1. The width WC of the wide end 163c2 is preferably 3.0 μm to 5.0 μm, and for example, it is set to 3.6 μm.

[0168] The width of the widened portion 163c3 smoothly increases from the narrow end 163c1 toward the wide end 163c2. According to this structure, the tapered portion 163c smoothly extends the width of the monitoring optical waveguide 130c in the direction of propagation of the monitoring light.

[0169] The tapered portion 164c constitutes part of an optical waveguide for propagating monitoring light. The tapered portion 164c is disposed on the monitoring port 131c side with reference to the intersection. The tapered portion 164c has a wide end portion 164c1 located on the optical branch portion 120c side, a narrow end portion 164c2 located on the monitoring port 131c side, and a narrowing portion 164c3 disposed between the wide end portion 164c1 and the narrow end portion 164c2.

[0170] The width of the wide end 164c1 is the same as the width WC of the wide end 163c2. The width of the narrow end 164c2 is the same as the width WB (e.g., 3.0 μm) of the monitoring optical waveguide 130c. The width of the narrowing portion 164c3 smoothly decreases from the wide end 164c1 toward the narrow end 164c2. According to this structure, the tapered portion 164c smoothly reduces the width of the monitoring optical waveguide 130b in the direction of propagation of the monitoring light.

[0171] The length L5 of the widened portion 163c3 (refer to) Figure 7 The length L6 of the narrowing section 164c3 (refer to) Figure 7The lengths L5 of the widening portion 163c3 and L6 of the narrowing portion 164c3 are not particularly limited, but are preferably 50μm to 150μm. For example, both lengths L5 and L6 are set to 100μm.

[0172] The cross-shaped portion 165c forms a cross and constitutes the intersection center of the monitoring optical waveguide 130c and the modulation optical waveguide 140b. The cross-shaped portion 165c connects the wide end 161c2 of the tapered portion 161c to the wide end 162c1 of the tapered portion 162c. The cross-shaped portion 165c connects the wide end 163c2 of the tapered portion 163c to the wide end 164c1 of the tapered portion 164c.

[0173] The cross waveguide 160c is configured to extend the waveguide width of both the monitoring light and the display light at the intersection of the monitoring optical waveguide 130c and the modulation optical waveguide 140b. The monitoring light and display light pass through the cross waveguide 160c in a multimode configuration. This reduces cross-loss and increases light propagation, thereby increasing the output light quantity at the monitoring port 131c and the optical output port 191.

[0174] Here, refer to Figure 7 The structure of cross waveguide 160c was explained, but cross waveguides 160a and 160b can also be set to the same structure.

[0175] Furthermore, when multiple intersecting waveguides are arranged in the same optical waveguide, a portion of the tapered section can be omitted, and the intersecting waveguides can be connected to each other. In this embodiment, as... Figure 8 As shown, cross waveguide 160a and cross waveguide 160b are interconnected.

[0176] Cross waveguide 160a is disposed at the intersection of monitoring optical waveguide 130b and modulation optical waveguide 140a. For example... Figure 8 As shown, the cross waveguide 160a has three tapered portions 161a, 163a, and 164a, as well as a cross portion 165a.

[0177] Cross waveguide 160b is disposed at the intersection of monitoring optical waveguide 130c and modulation optical waveguide 140a. For example... Figure 8 As shown, the cross waveguide 160b has three tapered portions 162b, 163b, and 164b, as well as a cross portion 165b.

[0178] Cross waveguide 160a does not have a tapered portion on the side closer to the optical modulation section 170a than the cross portion. Cross waveguide 160b does not have a tapered portion on the side closer to the optical branch section 120a than the cross portion. Instead, the cross portion 165a of cross waveguide 160a and the cross portion 165b of cross waveguide 160b are connected by a connecting portion 166. The width WD of the connecting portion 166 is preferably 2.0 μm to 5.0 μm, for example, and is set to 3.6 μm.

[0179] When multiple intersecting waveguides are arranged on the same optical waveguide, the tapered portion between the intersecting waveguides can be omitted, and they can be connected by the connecting portion 166. As a result, the waveguide length of the tapered portion is shortened, thereby reducing optical loss caused by propagation.

[0180] High-order mode filters

[0181] Reference Figure 9 The high-order mode filters 150a, 150b, and 150c will be explained below. Figure 9 yes Figure 1 and Figure 2 A top view schematic diagram of the high-order mode filter 150a. Here, in Figure 9 The diagram illustrates the structure of the high-order mode filter 150a, but the high-order mode filters 150b and 150c have the same structure.

[0182] A high-order mode filter 150a is disposed between the cross waveguide 160b and the optical modulation section 170a.

[0183] In the modulation waveguide 140a, the display light after passing through the cross waveguides 160a and 160b is multimode. Additionally, depending on the mounting accuracy of the visible light laser sources 301a, 301b, and 301c, the light may become multimode upon incidence. To improve the modulation efficiency of the optical modulation unit 170a, it is necessary to remove higher-order modes of the display light and convert it to single-mode.

[0184] The high-order mode filter 150a is configured to convert the high-order modes of the displayed light into single-mode light. More specifically, the high-order mode filter 150a has a curved waveguide 150a1 that is formed into a semi-circular arc shape when viewed from above, and curved portions 150a2 and 150a3 connecting the curved waveguide 150a1 to the modulation optical waveguides 140a and 151a. The curved portions 150a2 and 150a3 are respectively configured to bend the optical waveguides by 90°. The semi-circular curved waveguide 150a1 is connected between the curved portions 150a2 and 150a3.

[0185] Higher-order modes of light are easily lost when passing through curved optical waveguides due to their structural characteristics. By allowing multimode light to pass through a curved optical waveguide, selective conversion to single-mode light can be achieved by allowing only specific modes to pass through. The higher-order mode filter 150a is configured to use a curved waveguide 150a1 to remove higher-order modes from the displayed light for conversion to single-mode light.

[0186] In order to convert the multimode of the display light passing through the bent waveguide 150a1 into single-mode light, it is preferable to appropriately set the shape of the bent waveguide 150a1.

[0187] The width WE of the curved waveguide 150a1 is preferably 0.4μm to 0.8μm, for example, it is set to 0.6μm.

[0188] The curvature (radius of curvature R) of the curved waveguide 150a1 is preferably set individually according to the wavelength of the display light (e.g., the three primary colors: red, green, and blue). The radius of curvature R refers to the distance from the center of the semicircular arc to the center of the optical waveguide. When the display light is red (wavelength 637 nm), the radius of curvature R of the curved waveguide 150a1 is preferably 40 μm to 80 μm, for example, set to 60 μm. When the display light is green (wavelength 520 nm), the radius of curvature R of the curved waveguide 150a1 is preferably 60 μm to 100 μm, for example, set to 80 μm. When the display light is blue (wavelength 455 nm), the radius of curvature R of the curved waveguide 150a1 is preferably 100 μm to 140 μm, for example, set to 120 μm.

[0189] In this embodiment, the high-order mode filter 150a is configured to remove the high-order mode of red light, the high-order mode filter 150b is configured to remove the high-order mode of green light, and the high-order mode filter 150c is configured to remove the high-order mode of blue light.

[0190] By effectively removing the higher-order modes contained in the display light of each wavelength using high-order mode filters 150a, 150b, and 150c, the display light modulated by the light modulation units 170a, 170b, and 170c is converted to single-mode, thereby improving the modulation efficiency of the light modulation units 170a, 170b, and 170c.

[0191] <Manufacturing Method of Light Source Module>

[0192] The manufacturing method of the light source module 1A is described.

[0193] When manufacturing the light source module 1A, firstly, the optical device 10A is fabricated and prepared. The optical device 10A can be fabricated using known methods based on the designed optical waveguide pattern. Specifically, a substrate 101 of a specified thickness is prepared, and an optical functional layer 102, an electrode 200, and a protective layer 106 are stacked on the substrate 101. For example, when a lithium niobate film is formed as an epitaxial film on a single-crystal substrate made of sapphire or the like, the epitaxial film is formed by sputtering, CVD, or other methods, in accordance with the crystal orientation of the single-crystal substrate. The ridge 103b can be formed, for example, by photolithography to create a pattern (mask) on the lithium niobate film and then by dry etching.

[0194] Next, the relative positions of the visible light laser sources 301a, 301b, and 301c with respect to the optical device 10A are adjusted and fixed by active alignment.

[0195] Figure 10 This diagram illustrates the active alignment performed during the manufacturing process of the light source module 1A in this embodiment. Figure 10 The diagram schematically illustrates the active alignment of the visible light laser source 301a.

[0196] During active alignment of the visible light laser source 301a, the visible light laser source 301a is positioned near the light input port 110a, and an optical detection device 310 is positioned near the monitoring port 131a. The optical detection device 310 is a device for detecting the amount of light (light intensity), such as a photodetector that outputs an electrical signal corresponding to the amount of light received. The optical detection device 310 is used to detect the amount of light output from the monitoring port 131a.

[0197] Visible light incident from the optical input port 110a propagates in the input optical waveguide 111a, the optical branch 120a, and the monitoring optical waveguide 130a, and is emitted as monitoring light from the monitoring port 131a. In the optical device 10A, the optical branch 120a is arranged in front of the optical modulation section 170a.

[0198] In cases where the monitoring light is configured to pass through the optical modulation unit 170a, sometimes insufficient monitoring light cannot be obtained due to the initial phase difference between the branch waveguides 172a and 173a in the optical modulation unit 170a. In such cases, it is necessary to apply a voltage to the optical modulation unit 170a to adjust the phase of the light propagating in the branch waveguides 172a and 173a.

[0199] In contrast, in the optical device 10A of this embodiment, the visible light after being split by the optical branch 120a does not pass through the optical modulation section 170a and is emitted as monitoring light from the monitoring port 131a. Therefore, in this embodiment, it is not necessary to supply power to the optical device 10A to perform phase adjustment in the optical modulation section 170a, and sufficient amount of monitoring light can be emitted from the monitoring port 131a.

[0200] Visible light emitted from the visible light laser source 301a is incident on the optical input port 110a, and light emitted from the monitoring port 131a is incident on the optical detection device 310. The optical detection device 310 detects the output light quantity of the monitoring port 131a and outputs the detection result. Based on the detection result of the optical detection device 310, the relative position of the visible light laser source 301a with respect to the optical device 10A is adjusted so that the output light quantity of the monitoring port 131a is above a certain level, ideally at its maximum. The relative position referred to here refers to the xyz coordinate position of the visible light laser source 301a with respect to the optical device 10A, and the orientation of the visible light laser source 301a with respect to the optical device 10A (the incident angle of visible light onto the optical device 10A).

[0201] Figure 11 This diagram illustrates the concept of active alignment performed in this embodiment. Figure 11 The diagram shows the area near the optical input port 110a on the first end face 11.

[0202] like Figure 11 As shown, visible light emitted from the visible light laser source 301a illuminates the vicinity of the light input port 110a. The visible light has an illumination range (spot S) with a certain width. The optical axis of the visible light, which is the laser, is located at the center of the spot S. Typically, the output light quantity of the monitoring port 131a is maximized by aligning the center position CE of the light input port 110a with the optical axis of the visible light.

[0203] During active alignment, the output light intensity of the monitoring port 131a, detected in real time by the optical detection device 310, is determined to maximize the output light intensity and thus determine the relative position of the visible light laser source 301a with respect to the optical device 10A. For example, while keeping the emitting surface of the visible light laser source 301a facing the first end face 11 at a certain distance, the visible light laser source 301a is moved along the Y and Z directions, thereby determining the position where the output light intensity of the monitoring port 131a is maximized.

[0204] When the output light intensity of the monitoring port 131a is at its maximum, the optical axis of the visible light emitted from the visible light laser source 301a is aligned with the center position of the light input port 110a. In this state, the visible light laser source 301a is fixed to the optical device 10A. For example, the sub-carrier 302a on which the visible light laser source 301a is mounted is bonded to the substrate 101 of the optical device 10A.

[0205] In this way, by utilizing the active alignment of the monitoring light, the incident efficiency of visible light to the light input port 110a is optimized. In addition, the position adjustment of the visible light laser source 301a can be precisely performed, thereby improving the overall operating efficiency and optical performance of the optical device 10A.

[0206] Here, the active alignment related to the visible light laser source 301a is explained, but the same method can also be used for active alignment of the visible light laser sources 301b and 301c.

[0207] Anti-reflective devices

[0208] Visible light emitted from visible light laser sources 301a, 301b, and 301c is branched by optical branches 120a, 120b, and 120c and then emitted simultaneously from monitoring ports 131a, 131b, and 131c and optical output port 191.

[0209] Monitoring light is required when performing active alignment, but it is not required when using display light emitted from the light output port 191. However, monitoring light is emitted from monitoring ports 131a, 131b, and 131c even when monitoring light is not required.

[0210] Figure 12 This diagram illustrates the state in which anti-reflective devices 320 are arranged near the monitoring ports 131a, 131b, and 131c of the light source module 1A in this embodiment. (See diagram for example.) Figure 12 As shown, by configuring the anti-reflective device 320 in the monitoring ports 131a, 131b, and 131c, leakage of the monitoring light can be prevented when using the display light. This suppresses visual flicker caused by leakage of the monitoring light and prevents interference with the display light.

[0211] The anti-reflection device 320 has the function of attenuating or scattering unwanted monitoring light emitted from monitoring ports 131a, 131b, and 131c. As the anti-reflection device 320, for example, a light attenuation device such as silicon material or an ND filter, or a light scattering device such as a diffuser or a textured component can be used.

[0212] The anti-reflective device 320 can be configured to contact the second end face 12 or to be configured at a position that is a certain distance away from the second end face 12.

[0213] The anti-reflective device 320 can also be configured to be detachable from the monitoring ports 131a, 131b, and 131c. When monitoring light is not required, the monitoring ports 131a, 131b, and 131c are covered by the anti-reflective device 320. When monitoring light is required, the anti-reflective device 320 is removed from the monitoring ports 131a, 131b, and 131c.

[0214] <Optical System>

[0215] The optical system 500 in this embodiment will be described. Figure 13 This is a conceptual diagram of the optical system 500 in this embodiment.

[0216] The optical system 500, for example, constitutes an image display device for displaying information that can be visually recognized as an image (still image and moving image). The optical system 500 can be installed, for example, in an eyeglass-type terminal such as an XR glasses 600.

[0217] Figure 13 The optical system 500 shown includes a light source module 510, an optical system 520, a laser driver 530, an optical scanning mirror driver 540, and a video controller 550 that controls these drivers.

[0218] In the optical system 500, the light source module 1A of this embodiment can be mounted as the light source module 510. The light source module 510 is, for example, disposed in the frame 601 of the XR glasses 600.

[0219] The optical system 520 performs optical processing on the emitted light LE emitted from the light source module 510. The emitted light LE is visible light (display light) emitted from the light output port 191 of the light source module 1A in this embodiment.

[0220] The optical system 520 includes, for example, a collimating lens 521, a slit 522, an ND filter 523, and a light scanning mirror 524. Figure 13 The optical system 520 shown is one example, but other structures are also possible. The light source module 510 and the light scanning mirror 524 constitute the optical engine of this disclosure.

[0221] As the optical scanning mirror 524, a MEMS mirror can be used, for example. In order to project a two-dimensional image, a biaxial MEMS mirror that vibrates to change its angle in the horizontal and vertical directions to reflect the laser is preferably used as the optical scanning mirror 524.

[0222] exist Figure 13In the XR glasses 600 shown, the light source module 510 mounted on the frame 601 emits outgoing light LE. The outgoing light LE is reflected by the light scanning mirror 524, and then reflected by the lens 602 of the XR glasses 600. The light reflected by the lens 602 enters the eyeball and forms an image on the retina. Thus, it can be visually recognized as an image.

[0223] [Derivative examples of the first embodiment]

[0224] Figure 14 This is a top view of the light source module 1A in a derivative example of the first embodiment. Figure 15 It shows from Figure 14 A top view of the light source module 1A with the electrodes 200 and pads 201 removed.

[0225] like Figure 14 and Figure 15 As shown, the optical output port 191 can also be configured on the second end face 12. The output optical waveguide 181, which is connected to the optical wave combiner 180, extends linearly in the X direction and is connected to the optical output port 191 provided on the second end face 12. By configuring the optical output port 191 on the second end face 12, which is located on the opposite side of the light incident surface (first end face 11), the installation flexibility of the light source module 1A can be improved.

[0226] [Second Implementation]

[0227] The second embodiment of this disclosure will be described. Figure 16 This is a top view of the light source module 1B in this embodiment. Figure 17 It shows from Figure 16 The light source module 1B is shown in a top view without the state of the electrode 200 and the pad portion 201. In the second embodiment, the same reference numerals are used to label the same structural elements as in the first embodiment, and descriptions are omitted where appropriate.

[0228] The light source module 1B in the second embodiment includes an optical device 10B. The optical device 10B differs from the optical device 10A in the first embodiment in that the Mach-Zehnder type optical waveguides constituting the optical modulation sections 170a, 170b, and 170c are composed of folded-back optical waveguides. Furthermore, the electrodes 200 of the optical device 10B are shaped to fit the folded-back optical waveguide.

[0229] like Figure 16 and Figure 17As shown, the branch waveguides 172a and 173a constituting the optical modulation section 170a have fold-back portions 176 and 177 that reverse the direction of light propagation. The branch waveguides 172a and 173a are bent into a U-shape at the two fold-back portions 176 and 177. Except for the fold-back portions 176 and 177, the branch waveguides 172a and 173a are straight and extend parallel to the Y-direction. Similarly, the branch waveguides 172b and 173b constituting the optical modulation section 170b, and the branch waveguides 172c and 173c constituting the optical modulation section 170c, are also bent into a U-shape at the fold-back portions 176 and 177.

[0230] By employing folded-back optical waveguides in the optical modulation sections 170a, 170b, and 170c, the lengths (lengths in the X direction) of the optical input ports 110a, 110b, and 110c of the optical device 10B in the light incident direction can be shortened. As a result, the overall size of the optical device 10B can be miniaturized.

[0231] Furthermore, the monitoring optical waveguides 130a, 130b, and 130c are connected to the monitoring ports 131a, 131b, and 131c disposed on the second end face 12, and extend along the light incident direction (X direction) of the optical input ports 110a, 110b, and 110c. By shortening the length of the optical device 10B in the X direction, the monitoring optical waveguides 130a, 130b, and 130c can be shortened, thereby reducing the propagation loss of the monitoring light.

[0232] Furthermore, by employing a folded-back optical waveguide, the lengths of the branch waveguides 172a, 173a, 172b, 173b, 172c, and 173c used to apply the electric field can be adequately ensured. As a result, the driving voltage required for modulation of the display light can be reduced, thereby reducing the overall power consumption of the optical device 10B.

[0233] <Derivative Examples of the Second Implementation>

[0234] Figure 18 This is a top view of the light source module 1B in a derivative example of the second embodiment. Figure 19 It shows from Figure 18 A top view of the light source module 1B with the electrodes 200 and pads 201 removed.

[0235] like Figure 18 and Figure 19 As shown, the optical output port 191 can also be configured on the second end face 12. The output optical waveguide 181, which is connected to the optical wave combiner 180, extends linearly along the X direction and is connected to the optical output port 191 configured on the second end face 12. By configuring the optical output port 191 on the second end face 12, which is located on the opposite side of the light incident surface (first end face 11), the installation flexibility of the light source module 1B can be improved.

[0236] The light source module 1B in the second embodiment can perform active alignment in the same way as in the first embodiment. Furthermore, the anti-reflective device 320 can also be configured to integrate the light source module 1B into the light system 500.

[0237] [Third Implementation Method]

[0238] The third embodiment of this disclosure will be described. Figure 20 This is a top view of the light source module 1C in this embodiment. Figure 21 It shows from Figure 20 The light source module 1C is shown in a top view without the state of the electrode 200 and the pad portion 201. In the third embodiment, the same reference numerals are used to label the same structural elements as in the first and second embodiments, and descriptions are omitted where appropriate.

[0239] The light source module 1C in the third embodiment has an optical device 10C. The optical device 10C differs from the optical device 10A in the first embodiment in that the modulation optical waveguides 151a, 151b, and 151c are bent approximately vertically at the bends 152a, 152b, and 152c.

[0240] like Figure 20 and Figure 21 As shown, the modulation optical waveguide 151a is bent approximately vertically at the bend 152a disposed between the high-order mode filter 150a and the optical modulation section 170a. Branch waveguides 172a and 173a constituting the optical modulation section 170a extend along the Y direction. Similarly, the modulation optical waveguide 151b is bent approximately vertically at the bend 152b disposed between the high-order mode filter 150b and the optical modulation section 170b. Branch waveguides 172b and 173b constituting the optical modulation section 170b extend along the Y direction. Similarly, the modulation optical waveguide 151c is bent approximately vertically at the bend 152c disposed between the high-order mode filter 150c and the optical modulation section 170c. Branch waveguides 172c and 173c constituting the optical modulation section 170c extend along the Y direction.

[0241] The output optical waveguide 181, which is connected to the optical wave combination section 180, extends in a straight line along the Y direction and is connected to the optical output port 191 disposed on the fourth end face 14.

[0242] In this embodiment, by increasing the length of the optical device 10C in the Y direction, sufficient lengths of the branch waveguides 172a, 173a, 172b, 173b, 172c, and 173c for modulating light can be ensured. On the other hand, the length of the optical device 10C in the X direction can be shortened.

[0243] Monitoring optical waveguides 130a, 130b, and 130c are connected to monitoring ports 131a, 131b, and 131c disposed on the second end face 12, and extend along the light incident direction (X direction) of the optical input ports 110a, 110b, and 110c. By shortening the length of the optical device 10B in the X direction, the monitoring optical waveguides 130a, 130b, and 130c can be shortened, thereby reducing the propagation loss of the monitoring light.

[0244] The light source module 1C in the third embodiment can perform active alignment in the same way as in the first embodiment. Furthermore, the anti-reflective device 320 can also be configured to integrate the light source module 1C into the light system 500.

[0245] [Fourth Implementation Method]

[0246] The fourth embodiment of this disclosure will be described. Figure 22 This is a top view of the light source module 1D in this embodiment. Figure 23 It shows from Figure 22 The light source module 1D is a top view diagram omitting the state of the electrode 200 and the pad portion 201. In the fourth embodiment, the same reference numerals are used to label the same structural elements as in the third embodiment, and descriptions are omitted where appropriate.

[0247] The light source module 1D in the fourth embodiment includes an optical device 10D. The optical device 10D differs from the optical device 10C in the third embodiment in that the Mach-Zehnder type optical waveguides constituting the optical modulation sections 170a, 170b, and 170c are constructed using folded-back optical waveguides. Furthermore, in the optical device 10D, the modulation optical waveguides 140a, 140b, and 140c are bent approximately vertically at the bending portions 141a, 141b, and 141c, but they can also be bent at the modulation optical waveguides 151a, 151b, and 151c in the same manner as in the optical device 10C. Additionally, the electrodes 200 of the optical device 10D are shaped to accommodate the folded-back optical waveguides.

[0248] like Figure 22 and Figure 23 As shown, the branch waveguides 172a and 173a constituting the optical modulation section 170a have fold-back portions 176 and 177 that reverse the direction of light propagation. The branch waveguides 172a and 173a are bent into a U-shape at the two fold-back portions 176 and 177. Except for the fold-back portions 176 and 177, the branch waveguides 172a and 173a are straight and extend parallel to the Y-direction. Similarly, the branch waveguides 172b and 173b constituting the optical modulation section 170b, and the branch waveguides 172c and 173c constituting the optical modulation section 170c, are also bent into a U-shape at the fold-back portions 176 and 177.

[0249] By employing folded-back optical waveguides in the optical modulation sections 170a, 170b, and 170c, the lengths (lengths in the X direction) of the optical input ports 110a, 110b, and 110c of the optical device 10D in the light incident direction can be shortened. As a result, the overall miniaturization of the optical device 10D can be further achieved.

[0250] Furthermore, the monitoring optical waveguides 130a, 130b, and 130c are connected to the monitoring ports 131a, 131b, and 131c disposed on the second end face 12, and extend along the light incident direction (X direction) of the optical input ports 110a, 110b, and 110c. By shortening the length of the optical device 10D in the X direction, the monitoring optical waveguides 130a, 130b, and 130c can be shortened, thereby reducing the propagation loss of the monitoring light.

[0251] Furthermore, by employing a folded-back optical waveguide, the lengths of the branch waveguides 172a, 173a, 172b, 173b, 172c, and 173c used to apply the electric field can be adequately ensured. As a result, the driving voltage required for modulation of the display light can be reduced, thereby reducing the overall power consumption of the optical device 10D.

[0252] The light source module 1D in the fourth embodiment can perform active alignment in the same way as in the first embodiment. Furthermore, the anti-reflective device 320 can also be configured to integrate the light source module 1D into the light system 500.

[0253] The various embodiments of this disclosure have been described above, but this disclosure is not limited to these embodiments. Various modifications and alterations can be made without departing from the spirit of this disclosure, and the various embodiments can also be appropriately combined.

[0254] As described above, this disclosure has the effect of providing a stable and sufficient amount of monitoring light from the monitoring port, which is useful in XR glasses that utilize all optical device technologies that utilize visible light, especially those that project image display light.

[0255] This disclosure describes a limited number of embodiments, but those skilled in the art will recognize that various other embodiments possessing the advantages of this disclosure can be conceived without departing from the spirit and scope of this disclosure. Therefore, the technical scope of the disclosed subject matter should be defined only by the claims.

[0256] Explanation of reference numerals in the attached figures

[0257] 1A, 1B, 1C, 1D, 510: Light source modules

[0258] 10A, 10B, 10C, 10D: Optical devices

[0259] 11: First end face

[0260] 12: Second end face

[0261] 13: Third end face

[0262] 14: Fourth end face

[0263] 101: Substrate

[0264] 102: Optical Functional Layer

[0265] 103: Optical waveguide layer

[0266] 103a: Flat plate layer

[0267] 103b, 103b1, 103b2, 103b3: Ridge

[0268] 104: First Buffer Layer

[0269] 105: Second Buffer Layer

[0270] 106: Protective layer

[0271] 106a: End

[0272] 110a, 110b, 110c: Optical input ports

[0273] 111a, 111b, 111c: Input optical waveguides

[0274] 120a, 120b, 120c, 171a, 171b, 171c: Optical branching sections

[0275] 130a, 130b, 130c: Surveillance optical waveguides

[0276] 131a, 131b, 131c: Monitoring ports

[0277] 135a, 135b, 135c, 161a, 161c, 162b, 162c, 163a, 163b, 163c, 164a, 164b, 164c: Conical part

[0278] 135a1, 161c1, 162c2, 163c1, 164c2: Narrow end

[0279] 135a2, 161c2, 162c1, 163c2, 164c1: Wide end

[0280] 135a3, 161c3, 163c3: Widened section

[0281] 140a, 140b, 140c, 151a, 151b, 151c, 175a, 175b, 175c: Modulation optical waveguides

[0282] 141a, 141b, 141c, 152a, 152b, 152c, 182: Curved sections

[0283] 150a, 150b, 150c: High-order mode filters

[0284] 150a1: Bent waveguide

[0285] 150a2, 150a3: Bending section

[0286] 160a, 160b, 160c: Cross waveguides

[0287] 162c3, 164c3: Narrowing section

[0288] 165a, 165b, 165c: Cross-shaped intersection

[0289] 166: Connecting Part

[0290] 170a, 170b, 170c: Optical Modulation Section

[0291] 172a, 172b, 172c, 173a, 173b, 173c: Branch waveguides

[0292] 174a, 174b, 174c, 180: Photosynthetic wavelet

[0293] 176, 177: Turnback Section

[0294] 181: Output optical waveguide

[0295] 191: Optical output port

[0296] 200: Electrode

[0297] 200G: Reference electrode

[0298] 200S: Drive electrode

[0299] 201: Pad Section

[0300] 201a: Upper surface

[0301] 301a, 301b, 301c: Visible light laser sources

[0302] 302a, 302b, 302c: Subcarriers

[0303] 303a, 303b, 303c: Joints

[0304] 310: Optical inspection device

[0305] 320: Anti-reflective devices

[0306] 500: Optical System

[0307] 520: Optical System

[0308] 521: Collimating Lens

[0309] 522: Slit

[0310] 523: ND filter

[0311] 524: Optical Scanning Mirror

[0312] 530: Laser Driver

[0313] 540: Optical Scanning Mirror Driver

[0314] 550: Video Controller

[0315] 600: XR Glasses

[0316] 601: Eyeglass frames

[0317] 602: Lens

[0318] LE: Outgoing light

Claims

1. An optical device comprising a substrate and an optical functional layer formed on the main surface of the substrate, characterized in that, The optical functional layer has the following features: The optical input port corresponds to each of the multiple visible light laser sources and can be used to input visible light emitted from each visible light laser source. An input optical waveguide is provided, which is connected to each optical input port. The optical branch section has an input section connected to each input optical waveguide and two output sections; A monitoring optical waveguide, which is connected to the output of one of the optical branches; The monitoring port, which is connected to each monitoring optical waveguide, is used to emit monitoring light to the outside; The first optical waveguide is connected to the output section of the other side of each optical branch; An optical modulation section, which is connected to each of the first optical waveguides; The second optical waveguide is connected to each optical modulation section; The optical waveguide is connected to each of the second optical waveguides; An output optical waveguide, which is connected to the optically combined wave section; and The optical output port is connected to the output optical waveguide and is used to emit light that has been combined by the optical wave combiner to the outside.

2. The optical device according to claim 1, characterized in that, The width of the monitoring optical waveguide is wider than the width of the optical waveguide constituting the optical modulation section, and the optical device has a tapered portion for extending the width of the monitoring optical waveguide.

3. The optical device according to claim 1, characterized in that, The monitoring optical waveguide and the first optical waveguide have a cross waveguide at their intersection. The cross waveguide has a cross-shaped portion located at the center of the intersection and a tapered portion that extends the width of the monitoring optical waveguide or the first optical waveguide toward the cross-shaped portion.

4. The optical device according to claim 3, characterized in that, A high-order mode filter for removing higher-order modes of light is provided between the cross waveguide and the optical modulation section. The high-order mode filter has a curved waveguide bent with a predetermined curvature.

5. The optical device according to claim 1, characterized in that, The upper surface of the optical functional layer has a protective layer, and a portion of the pad portion that is electrically connected to the electrode of the optical modulation section is not covered by the protective layer and is exposed to the outside.

6. The optical device according to claim 1, characterized in that, The optical waveguide constituting the optical modulation section has a foldback section that reverses the direction of light propagation.

7. The optical device according to claim 1, characterized in that, At least a portion of the optical waveguide constituting the optical modulation section is formed in a direction orthogonal to the light incident direction of the optical input port.

8. A light source module, characterized in that, have: The optical device according to any one of claims 1 to 7; and The plurality of visible light laser sources.

9. A method for manufacturing a light source module, wherein the light source module is the light source module according to claim 8, and the manufacturing method is characterized in that, The visible light emitted from the visible light laser source is incident on the optical input port. The emitted light from the monitoring port is directed onto the optical detection device. Based on the detection results of the optical detection device, the relative position of the visible light laser source with respect to the optical device is adjusted. The visible light laser source is fixed relative to the optical device at a position such that the optical axis of the visible light emitted from the visible light laser source is aligned with the center position of the optical input port.

10. An optical engine, characterized in that, have: The light source module according to claim 8; and A light-scanning reflector changes its angle to reflect light emitted from the light source module for image display.

Images