Kink-free high fill factor wide area semiconductor laser on trimmed substrate

Abstract

The invention relates to a kink-free high fill factor wide area semiconductor laser on an off-cut substrate. The semiconductor laser may include a trimmed substrate having a cut angle of at least about 6 degrees (DEG). The semiconductor laser may include an epitaxial structure over a trimmed substrate. A first sidewall formed by the trimmed substrate and the epitaxial structure may be parallel to a second sidewall formed by the trimmed substrate and the epitaxial structure. A front facet formed by the trimmed substrate and the epitaxial structure may be parallel to a back facet formed by the trimmed substrate and the epitaxial structure. The cut angle of the trimmed substrate may cause the first sidewall not to be perpendicular to the epitaxial layer of the epitaxial structure. The cut angle of the trimmed substrate may cause the second sidewall not to be perpendicular to the epitaxial layer of the epitaxial structure.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 506,731, entitled “KINK-FREE HIGH FILL-FACTORBROAD AREA SEMICONDUCTOR LASER ON AN OFF-CUT SUBSTRATE” filed on June 7, 2023. The disclosure of that prior application is considered a part of and incorporated by reference into this patent application. Technical Field

[0003] The present disclosure relates generally to semiconductor lasers, and to high fill factor wide area semiconductor lasers on cropped substrates. Background Art

[0004] A wide area laser diode is an edge emitting laser diode in which the emission region of the front facet of the wide area laser diode has the shape of a wide stripe or ridge. The fill factor of a wide area laser diode is defined as the percentage (or ratio) of the width of the emission region compared to the width of the wide area laser diode. Summary of the invention

[0005] In some embodiments, a semiconductor laser includes: a cut substrate having a cut angle of at least about 6 degrees (°); and an epitaxial structure located above the cut substrate; wherein a first sidewall formed by the cut substrate and the epitaxial structure is parallel to a second sidewall formed by the cut substrate and the epitaxial structure, wherein a front facet formed by the cut substrate and the epitaxial structure is parallel to a rear facet formed by the cut substrate and the epitaxial structure, wherein the cut angle of the cut substrate causes the first sidewall to be non-perpendicular to an epitaxial layer of the epitaxial structure, and wherein the cut angle of the cut substrate causes the second sidewall to be non-perpendicular to the epitaxial layer of the epitaxial structure.

[0006] In some embodiments, an optical device includes: a trimmed substrate having a cutting angle of at least about 6°; and an epitaxial structure located above the trimmed substrate; wherein a first sidewall of the optical device is parallel to a second sidewall of the optical device, wherein a front facet of the optical device is parallel to a rear facet of the optical device, wherein the front facet and the rear facet are perpendicular to an epitaxial layer of the epitaxial structure, and wherein the first sidewall and the second sidewall are not perpendicular to the epitaxial layer of the epitaxial structure.

[0007] In some embodiments, a laser device includes: a substrate having a cutting angle greater than or equal to about 6°; and an epitaxial structure located above the cut substrate, the epitaxial structure including a plurality of epitaxial layers; wherein sidewalls of the laser device are parallel to each other, wherein the sidewalls are not perpendicular to the plurality of epitaxial layers, wherein facets of the laser device are parallel to each other, and wherein the facets of the laser device are perpendicular to the plurality of epitaxial layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1A-1B is a diagram of an example implementation described herein.

[0009] Figure 2A-2B is a graph of an example of a light-current (LI) curve associated with an optical device.

[0010] Figure 3 is a diagram illustrating one example implementation for achieving kink-free LI performance for the optical devices described herein. DETAILED DESCRIPTION

[0011] The following detailed description of example embodiments refers to the accompanying drawings.The same reference numbers in different drawings may identify the same or similar elements.

[0012] In order to achieve high power output (e.g., high optical power output) of a laser device (e.g., a wide area laser device) and reduce the size of the laser device and / or the costs associated with manufacturing the laser device, a high fill factor of the laser device is preferred. For example, a fill factor of greater than or equal to 60% is often preferred. However, in many cases, such a high fill factor enables non-preferred in-epi-plane lasing within the laser device. That is, a high fill factor often enables the formation of ring modes and / or other non-preferred in-epi-plane lasing modes within the epitaxial structure of the laser device.

[0013] For example, a near-infrared (NIR) diode laser device may include an epitaxial structure grown on a gallium arsenide (GaAs) substrate having a crystal orientation of (001), which means that the shape of a single emitter facet is rectangular. In the lateral direction, both side facets of the laser device are perpendicular to the epitaxial plane and form a Fabry-Perot (FP) resonator that supports lateral laser emission. In addition, a high filling factor may result in the formation of a ring resonator in the epitaxial plane through the front facet, the back facet, and the side facets of the laser device, which supports ring laser emission in the epitaxial plane (e.g., under high current pumping). In the unpumped passive region, the quantum well (QW) temperature is significantly lower than the temperature in the pumped region. Therefore, the unpumped passive region may be transparent to the laser signal (e.g., because the lower temperature results in a higher band gap energy). The reflection of the ring laser signal on one side of the laser device is a total internal reflection, which is lossless to the ring laser signal. For a single emitter and a long cavity with a filling factor exceeding 60%, the ring laser mode has sufficient gain to balance the mirror loss and other losses, so the ring laser mode has a chance to perform laser emission. It is worth noting that lateral lasing has a lower chance of lasing because lateral lasing mirror losses are likely to be at least ten times higher than the designed FP resonator ridge cavity of the laser device. However, lateral FP resonators and in-plane ring resonators enhance QW spontaneous emission, which results in losses to the laser device. These epitaxial in-plane lasers will compete with the designed ridge waveguide lasers. Therefore, the power performance (e.g., optical power performance) of the laser device will be inconsistent or unpredictable (e.g., when the current applied to the laser device is changed). This is indicated by the light-current (LI) curve associated with the laser device, which often has kinks and is not smooth (e.g., as described in this article about Figure 2A As a result, this laser device cannot be used in applications requiring more consistent and predictable power performance.

[0014] Some embodiments described herein provide an optical device (e.g., a laser device, such as a wide area semiconductor laser) comprising a trimmed substrate and an epitaxial structure above the trimmed substrate. In some embodiments, the trimmed substrate may have a trim angle of at least about 6°. In some embodiments, the trim angle of the trimmed substrate is such that a first sidewall of the optical device is not perpendicular to an epitaxial layer of the epitaxial structure, and similarly such that a second sidewall of the optical device is not perpendicular to the epitaxial layer of the epitaxial structure.

[0015] In some embodiments, the cut angle prevents total internal reflection at the waveguide and cladding interface, which means that lateral and ring cavities are absent within the optical device. Thus, unwanted lateral and ring lasing within the epitaxial structure is eliminated, thereby improving the power performance of the optical device. Thus, even when the optical device has a high fill factor (e.g., a fill factor greater than or equal to 60%), the power performance of the optical device (e.g., when varying the current of the optical device) is more consistent and predictable than the power performance of the laser device described above. This is indicated by the LI curve associated with the optical device having no kinks (e.g., "kink-free") and being smooth (e.g., as described herein with respect to Figure 2B As described above). In addition, the power performance of the optical device is more efficient because an increase in the current applied to the optical device reliably results in an increase in the power of the optical device. Therefore, the optical device can be used in applications that require more consistent and predictable power performance (and in which the above-mentioned laser devices cannot be used). Additional details are provided below.

[0016] Figure 1A-1B is a diagram of an example implementation 100 described herein. Figure 1A-1B As shown, each example embodiment 100 may include an optical device 102 . Figure 1A shows a top view of the optical device 102, and Figure 1B A rear end view of the optical device 102 is shown (eg, from the Figure 1A 102). Note that a front view of the optical device 102 (e.g., from the left side of the optical device 102) Figure 1A The front facet 130 of the optical device 102 as shown in FIG. Figure 1B Rear view shown.

[0017] like Figure 1B As shown, the optical device 102 may include a trimmed substrate 104 and an epitaxial structure 106 disposed above (e.g., directly on or indirectly on) the trimmed substrate 104 (e.g., the top surface of the trimmed substrate 104). The epitaxial structure 106 may include a first cladding layer 108 (e.g., disposed above the trimmed substrate 104), a first waveguide layer 110 (e.g., disposed above the first cladding layer 108), an active layer 112 (e.g., disposed above the first waveguide layer 110), a second waveguide layer 114 (e.g., disposed above the active layer 112), a second cladding layer 116 (e.g., disposed above the second waveguide layer 114), and / or a cap layer 118 (e.g., disposed above the second cladding layer 116). The layers of the epitaxial structure 106 are also trimmed in the same manner as the trimmed substrate 104, thereby forming a structure as shown in FIG. Figure 1B Parallelogram or angled section as shown. Figure 1AAs further shown, due to the cut edge angle θ of the optical device 102 , a portion of the side wall 126 - 2 is visible from a top view of the optical device 102 .

[0018] The optical device 102 may be a laser device or another type of light emitting device. For example, the optical device 102 may be a wide area semiconductor laser configured to emit a laser beam, such as a near infrared (NIR) laser beam (e.g., a beam having a wavelength in a range of about 700 nanometers (nm) to about 1600 nm). The optical device 102 may be configured to generate, propagate, and emit the laser beam along an emission axis 120 (e.g., between a rear end of the optical device 102 and a front end of the optical device 102, or vice versa).

[0019] In some embodiments, the trimmed substrate 104 may be a gallium arsenide (GaAs) substrate (e.g., a GaAs substrate having a crystal axis orientation of (001)). Alternatively, in some embodiments, the trimmed substrate 104 may be an indium phosphide (InP) substrate or another type of substrate (e.g., a substrate having a Bravais lattice structure). Additionally or alternatively, the trimmed substrate 104 may be doped. For example, the trimmed substrate 104 may be an n-doped substrate. The trimmed substrate 104 may be formed from a wafer (e.g., a slice) from a crystal ingot, and before the substrate is cut at the trim angle θ, a layer of a quartz crystal may be formed over the trimmed substrate 104 (e.g., at a temperature such as 400 °C). Figure 1B Various other layers of the epitaxial structure 106 are formed (eg, grown) above the top surface of the edge-cut substrate 104 as shown. Additional details regarding the edge-cut substrate 104 are provided below.

[0020] The first cladding layer 108 can confine light (e.g., a laser beam) (e.g., vertically) within the first waveguide layer 110, the active layer 112, and / or the second waveguide layer 114. In some embodiments, the first cladding layer 108 can be doped. For example, the first cladding layer 108 can be an n-doped cladding layer. The first waveguide layer 110 can guide light (e.g., a laser beam) in a specific direction within the optical device 102 (e.g., along an emission axis 120 of the optical device 102) and / or confine light (e.g., vertically) within the active layer 112. The active layer 112 can serve as an active region of the optical device 102 (e.g., a laser active region within a laser cavity when the epitaxial structure 106 is included in a laser device). The active layer 112 can include one or more QWs. The second waveguide layer 114 can guide light (e.g., a laser beam) in a particular direction within the optical device 102 (e.g., along an emission axis 120 of the optical device 102), and / or confine light (e.g., vertically) within the active layer 112. The second cladding layer 116 can confine light (e.g., a laser beam) (e.g., vertically) within the first waveguide layer 110, the active layer 112, and / or the second waveguide layer 114. In some embodiments, the second cladding layer 116 can be doped. For example, the second cladding layer 116 can be a p-doped cladding layer. The cap layer 118 can protect other layers of the epitaxial structure 106 (e.g., when the cap layer 118 is formed as a top layer of the epitaxial structure 106). In some embodiments, the cap layer 118 can be highly doped. For example, the cap layer 118 can be a highly doped p-doped cap layer.

[0021] In some embodiments, the edged substrate 104 is formed such that the sidewalls of the edged substrate 104 are not perpendicular to the surface of the edged substrate 104. Figure 1BAs shown, the trimmed substrate 104 can be formed to have a trim angle θ such that the sidewalls of the trimmed substrate 104 are not perpendicular to the bottom surface of the trimmed substrate 104. When the sidewalls of the trimmed substrate 104 are formed in this way, the sidewalls of the epitaxial structure 106 are also formed to be not perpendicular to the surface (e.g., the bottom surface or the side surface) of the epitaxial structure 106. In some embodiments, the trim angle θ can be at least about 6°, which can significantly reduce the lateral internal reflection of the sidewall 126. In some embodiments, the trim angle θ can be less than about 15°, which can maintain the quality and yield of the epitaxial layer. In some embodiments, the trim angle θ can be selected based on the refractive index contrast between the waveguide layer of the epitaxial structure 106 and the cladding layer of the epitaxial structure 106. For example, in order to eliminate lateral laser emission and ring laser emission, the minimum trim angle θ of the trimmed substrate 104 can be determined based on the refractive index contrast between the first waveguide layer 110 and the first cladding layer 108 (or by the refractive index contrast between the second waveguide layer 114 and the second cladding layer 116). As a specific example, for a vertical fundamental mode reflected by an angled sidewall, the minimum cut angle θ can be determined to be equal to (90°-sin -1 (n2 / n1)) / 2, where n1 is the refractive index of the first waveguide layer 110 and n2 is the refractive index of the first cladding layer 108.

[0022] In some embodiments, Figure 1B As shown, the first sidewall 126-1 formed by the trimmed substrate 104 and the epitaxial structure 106 is parallel to the second sidewall 126-2 formed by the trimmed substrate 104 and the epitaxial structure 106. That is, in some embodiments, the sidewalls 126 of the optical device 102 can be parallel to each other. In addition, the cutting angle θ of the trimmed substrate 104 makes the sidewall 126 not perpendicular to the epitaxial layer of the epitaxial structure 106. For example, the cutting angle θ of the trimmed substrate 104 makes the first sidewall 126-1 not perpendicular to the epitaxial layer of the epitaxial structure 106 (e.g., the first cladding layer 108, the first waveguide layer 110, the active layer 112, the second waveguide layer 114, the second cladding layer 116, and the cap layer 118). Similarly, the cutting angle θ of the trimmed substrate 104 causes the second sidewall 126 - 2 to be non-perpendicular to the epitaxial layers (eg, first cladding layer 108 , first waveguide layer 110 , active layer 112 , second waveguide layer 114 , second cladding layer 116 , and cap layer 118 ) of the epitaxial structure 106 .

[0023] In some embodiments, Figure 1A As shown, the front facet 130 formed by the trimmed substrate 104 and the epitaxial structure 106 is parallel to the rear facet 128 formed by the trimmed substrate 104 and the epitaxial structure 106. That is, in some embodiments, the facets of the optical device 102 can be parallel to each other. Figure 1A and Figure 1BIt is understood that in some embodiments, the front facet 130 and / or the back facet 128 can be perpendicular to the epitaxial layers in the epitaxial structure 106. For example, in some embodiments, the front facet 130 and the back facet 128 of the optical device 102 can be perpendicular to the first cladding layer 108, the first waveguide layer 110, the active layer 112, the second waveguide layer 114, the second cladding layer 116, or the cap layer 118. In some embodiments, as Figure 1B As further shown, the front facet 130 of the optic 102 and / or the back facet 128 of the optic 102 may have a parallelogram shape.

[0024] As described above, the trimmed substrate 104 with the trim angle θ provides an emitter with parallelogram-shaped facets that are oriented inward and outward. Figure 1A The emission direction of the page plane of the epitaxial structure 106 is perpendicular to the epitaxial layers in the epitaxial structure 106, which forms an FP cavity. In addition, the sidewalls 126 along the laser cavity are not perpendicular to the epitaxial layers of the epitaxial structure 106 (and can be parallel to each other), which means that the lateral FP resonator is not formed in the epitaxial plane. Here, if the first waveguide layer 110 has a higher refractive index than the first cladding layer 108, the second waveguide layer 114 has a higher refractive index than the second cladding layer 116, and the cut angle θ is large enough so that there is no total internal reflection at the waveguide / cladding interface, then no lateral cavity and no ring cavity are formed, which means that lateral laser emission and ring laser emission are eliminated in the optical device 102.

[0025] In some embodiments, the optical device 102 may include a pair of grooves 122 associated with controlling horizontal far-field divergence. These grooves 122 are optional. For example, Figure 1A-1B As shown, the optical device 102 may include a pair of grooves 122 (shown as grooves 122-1 and 122-2). Figure 1A As shown, the pair of grooves 122 may be formed in a surface (eg, top surface) of the optical device 102. Figure 1B As shown, a pair of trenches 122 may be formed in a surface (eg, a top surface) of the epitaxial structure 106 including a surface of the optical device 102 .

[0026] like Figure 1A As shown, the pair of grooves 122 may be formed in an inner region (e.g., a central region) of the surface of the optical device 102 (e.g., an inner region of the surface of the epitaxial structure 106). The pair of grooves 122 may be formed along a dimension substantially parallel to the emission axis 120 (e.g., within a tolerance range, which may be less than or equal to 1 degree, 2 degrees, and / or 3 degrees, etc.) in the inner region of the surface of the optical device 102 (e.g., along the inner region of the surface of the epitaxial structure 106). For example, as Figure 1AAs shown, the pair of grooves 122 can be formed along the length (eg, shown as a horizontal dimension) of the interior region of the surface of the optical device 102 .

[0027] In some embodiments, the pair of grooves 122 can define a ridge 124 of the optical device 102 (eg, a ridge 124 of the epitaxial structure 106). Figure 1A-1B As shown, the ridge 124 can be an area defined by the pair of grooves 122 in the inner region of the surface of the optical device 102. In some embodiments, the width of the ridge 124 can be defined as the distance between the inward edges of the pair of grooves 122. The fill factor of the optical device 102 can be defined as the percentage (or ratio) of the width of the ridge 124 compared to the width of the optical device 102. In some embodiments, the fill factor of the optical device 102 can be at least 60%, such as 61%, 62.5%, 65%, or 67.5%. That is, in some embodiments, the width of the ridge 124 of the optical device 102 is at least about 60% of the width of the optical device 102. In existing optical devices having sidewalls perpendicular to the epitaxial layer and a fill factor of at least 60%, the corresponding LI performance (see Figure 2A ) exhibits power loss to undesirable lasing modes (e.g., lateral lasing and circular lasing) during operation. In embodiments of the present invention, angled sidewalls 126 of epitaxial structure 106 prevent such power loss regardless of whether the fill factor is at least 60% (see Figure 2B ).

[0028] In some embodiments, the pair of grooves 122 can be formed using an etching technique (e.g., using a wet etching technique or a dry etching technique). In some embodiments, each groove 122 in the pair of grooves 122 can extend into at least the second cladding layer 116. For example, Figure 1B As shown, each trench 122 can extend through the cap layer 118 into the second cladding layer 116. In some embodiments, each trench 122 does not extend into the second waveguide layer 114 and / or does not extend into the active layer 112. In some embodiments, such as due to dry etching techniques, each trench 122 can have an axis that is aligned with the epitaxial formation axis of the optical device 102 (e.g., as shown in FIG. Figure 1B The sidewalls of the trench 122 may be substantially parallel (e.g., within a tolerance range, which may be less than or equal to 1 degree, 2 degrees, and / or 3 degrees, etc.) to the vertical direction shown. Thus, each trench 122 may have a "vertical" sidewall, such as Figure 1B Alternatively, each trench 122 may have sidewalls that form a non-zero angle with the epitaxial formation axis, such as due to use of a wet etching technique. Thus, in some embodiments, each trench 122 may have "non-vertical" sidewalls.

[0029] In some embodiments, the pair of grooves 122 can be formed to have a specific depth and / or width such that the pair of grooves 122 is configured such that the slow-axis far-field divergence angle associated with the optical device 102 satisfies a divergence angle threshold. That is, the pair of grooves 122 can be configured such that the slow-axis far-field divergence angle associated with the optical device 102 is less than or equal to the divergence angle threshold, which can be less than or equal to 7 degrees, 10 degrees, or 15 degrees, etc. For example, the depth and / or width of the pair of grooves 122 can define an effective refractive index contrast (e.g., in the slow-axis direction) of the second waveguide layer 114. In this way, the pair of grooves 122 can be formed to prevent the slow-axis far-field divergence angle associated with the optical device 102 from exceeding the divergence angle threshold.

[0030] In some embodiments, the use of the cut edge substrate 104 and the paired grooves 122 enables a wide area single emitter with kink-free LI performance and acceptable slow axis divergence angle. In some embodiments, the use of the cut edge substrate 104 simplifies wafer processing while reducing the cost of the optical device 102.

[0031] As mentioned above, Figure 1A-1B Provided as examples only. Other examples may be relevant to Figure 1A-1B Different than described.

[0032] Figure 2A-2B is a graph of an example of a light-current (LI) curve associated with an optical device.

[0033] Figure 2A An LI curve 202 associated with an optical device that does not include the trimmed substrate 104 described herein (e.g., does not include angled sidewalls) or the pair of grooves 122 is shown. The optical device can, for example, have a width of 400 micrometers (μm) and a length of 4.8 mm, and the ridges of the optical device can have a width of 250 μm and a length of 4.8 mm. Thus, the optical device can have a fill factor of 62.5% (e.g., 250 μm divided by 400 μm). Figure 2A As shown, the LI curve 202 includes a kink 204 where the power of the optical device (optical power, in watts (W)) decreases as the current applied to the optical device (in amperes (A)) increases (e.g., when the current applied to the optical device increases from about 9 A to 10 A). As further shown, the LI curve 202 is not smooth, such that an incremental change in current may result in a greater or lesser incremental change in the power of the optical device. As a result, the power performance of the optical device (e.g., when changing the current applied to the optical device) is inconsistent or unpredictable. Furthermore, in some cases, an increase in the applied current results in a decrease in the power of the optical device.

[0034] Figure 2B An LI curve 206 associated with an example configuration of an optical device 102 including a trimmed substrate 104 (e.g., including angled sidewalls) and a pair of grooves 122 as described herein is shown. The optical device 102 may, for example, have a width of 400 μm and a length of 5.5 mm, and the ridges 124 of the optical device 102 may have a width of 270 μm and a length of 5.5 mm. Thus, the example configuration of the optical device 102 may have a fill factor of 67.5% (e.g., 270 μm divided by 400 μm). As shown in FIG. Figure 2B As shown, the LI curve 206 does not include a kink. In addition, the LI curve 206 is smooth, so that incremental changes in the current applied to the optical device 102 result in incremental changes in the power of the optical device. Therefore, the power performance of the optical device 102 (e.g., when changing the current of the optical device) is better than that described herein. Figure 2A The power performance of the described optical device is more consistent and predictable. In addition, the power performance of the optical device 102 is more efficient because the increased current applied to the optical device 102 results in an increased power of the optical device 102.

[0035] As shown in LI curve 206, Figure 2A The optical device 102 provides improved power performance compared to the optical devices described herein. This is because the optical device 102 includes a cropped substrate 104 that produces angled sidewalls 126 in the epitaxial structure 106, which minimizes or prevents the formation of a donut mode and / or other non-preferred epitaxial in-plane lasing modes (e.g., as described herein) within the epitaxial structure 106 of the optical device 102. In this manner, the current applied to the optical device 102 is used to form a preferred lasing mode of the optical device 102. Therefore, in many cases, the optical device 102 provides higher power per ampere than a similar optical device that does not include a cropped substrate 104.

[0036] As mentioned above, Figure 2A-2B Provided as examples only. Other examples may be relevant to Figure 2A-2B Different than described.

[0037] Figure 3 is a diagram illustrating one example implementation for achieving kink-free LI performance for optical device 102.

[0038] exist Figure 3 In the example shown, a GaAs substrate with a 6° cut edge is used for the growth of an epitaxial structure (eg, epitaxial structure 106). Figure 3 in the plane of the page, or along the dark black axis of the wafer. Figure 3In the example shown, the substrate uses the EJ plane option, "OF" refers to the orientation plane (principal plane), and " <111> A” refers to the crystal orientation. In this example, after the grid is split, Figure 3 When the resulting grid bars are observed from directions A and B, the split facets have different shapes. Figure 3 As shown and described above, the front and rear facets are parallel to each other and perpendicular to the epitaxial layers within the epitaxial structure.

[0039] As mentioned above, Figure 3 are provided as examples. Other examples may be relevant to Figure 3 Different than described.

[0040] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive of the embodiments or to limit the embodiments to the precise forms disclosed. Modifications and variations may be made based on the above disclosure, or modifications and variations may be obtained from practicing the embodiments. In addition, unless the foregoing disclosure explicitly provides a reason why one or more embodiments may not be combined, any embodiments described herein may be combined.

[0041] Although specific combinations of features are described in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various embodiments. In fact, many of these features can be combined in a manner that is not specifically described in the claims and / or not disclosed in the specification. Although each dependent claim listed below may only directly depend on one claim, the disclosure of various embodiments includes each dependent claim combined with each other claim in the claim set. As used herein, the phrase "at least one" in the referenced item list refers to any combination of these items, including a single member. As an example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination of multiple identical items.

[0042] When a component or one or more components (e.g., a laser emitter or one or more laser emitters) is described or claimed (within a single claim or across multiple claims) as performing multiple operations or being configured to perform multiple operations, the language is intended to cover a wide variety of architectures and environments. For example, unless otherwise expressly required (e.g., via the use of "first component" and "second component" or other language that distinguishes components in a claim), the language is intended to cover a single component that performs or is configured to perform all operations, a group of components that collectively perform or are configured to perform all operations, a first component that performs or is configured to perform a first operation and a second component that performs or is configured to perform a second operation, or any combination of components that performs or is configured to perform operations. For example, when a claim has the form "one or more components are configured to: perform X; perform Y; and perform Z", the claim should be interpreted to mean "one or more components are configured to perform X; one or more (possibly different) components are configured to perform Y; and one or more (possibly different) components are configured to perform Z".

[0043] Any element, action or instruction used herein should not be interpreted as critical or necessary, unless explicitly described in this way. In addition, as used herein, the articles "one" and "an" are intended to include one or more projects, and can be used interchangeably with "one or more". In addition, as used herein, the article "the" is intended to include one or more projects quoted in conjunction with the article "the", and can be used interchangeably with "the one or more". In addition, as used herein, the term "set" is intended to include one or more projects (for example, a combination of related projects, unrelated projects, or related projects and unrelated projects), and can be used interchangeably with "one or more". In the case of only being intended to a project, the phrase "only one" or similar language is used. In addition, as used herein, the terms "have", "have", "contain" etc. are intended to be open terms. In addition, the phrase "based on" is intended to represent "at least partially based on", unless otherwise clearly stated. In addition, as used herein, the term "or" is intended to be inclusive when used in series, and can be used interchangeably with "and / or", unless otherwise clearly stated (for example, if used in combination with "or" or "only one of them"). Additionally, for ease of description, spatially relative terms such as "below," "beneath," "above," and the like may be used herein to describe the relationship of one element or feature to another element or feature shown in the accompanying drawings. Spatially relative terms are intended to encompass different orientations of the device, equipment, and / or element in use or operation in addition to the orientation depicted in the accompanying drawings. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein may likewise be interpreted accordingly.

Claims

1. A semiconductor laser comprising: a cut edge substrate having a cut angle of at least about 6 degrees (°); as well as an epitaxial structure located above the trimmed substrate; wherein a first sidewall formed by the trimmed substrate and the epitaxial structure is parallel to a second sidewall formed by the trimmed substrate and the epitaxial structure, wherein a front facet formed by the trimmed substrate and the epitaxial structure is parallel to a rear facet formed by the trimmed substrate and the epitaxial structure, wherein the cutting angle of the trimmed substrate makes the first sidewall non-perpendicular to the epitaxial layer of the epitaxial structure, and The cutting angle of the trimmed substrate makes the second sidewall non-perpendicular to the epitaxial layer of the epitaxial structure.

2. The semiconductor laser of claim 1, wherein the cutting angle is less than about 15°. 3 . The semiconductor laser of claim 1 , wherein the cut angle is based on a refractive index contrast between a waveguide layer of the epitaxial structure and a cladding layer of the epitaxial structure. 4 . The semiconductor laser according to claim 1 , wherein at least one of the front facet or the rear facet has a parallelogram shape. 5 . The semiconductor laser according to claim 1 , wherein at least one of the front facet or the back facet is perpendicular to the epitaxial layer within the epitaxial structure.

6. The semiconductor laser of claim 1, wherein the semiconductor laser has a fill factor of at least about 60%.

7. The semiconductor laser according to claim 1, wherein the semiconductor laser is a wide-area laser device for emitting a near-infrared (NIR) beam.

8. The semiconductor laser of claim 1, wherein the epitaxial structure comprises a set of trenches formed in a surface of the epitaxial structure.

9. An optical device comprising: a cut edge substrate having a cut angle of at least about 6 degrees (°); as well as an epitaxial structure located above the trimmed substrate; wherein the first side wall of the optical device is parallel to the second side wall of the optical device, wherein the front facet of the optical device is parallel to the back facet of the optical device, wherein the front facet and the back facet are perpendicular to the epitaxial layer of the epitaxial structure, and The first sidewall and the second sidewall are not perpendicular to the epitaxial layer of the epitaxial structure.

10. The optical device of claim 9, wherein the cutting angle is less than about 15°.

11. The optical device of claim 9, wherein the cutting angle is based on a refractive index contrast between a waveguide layer of the epitaxial structure and a cladding layer of the epitaxial structure.

12. The optical device of claim 9, wherein the front facet and the back facet have a parallelogram shape.

13. The optical device of claim 9, wherein the width of the ridge of the optical device is at least about 60% of the width of the optical device.

14. The optical device according to claim 9, wherein the optical device is a wide-area laser device for emitting a near-infrared (NIR) beam.

15. The optical device of claim 9, wherein the epitaxial structure comprises a set of grooves formed in a surface of the epitaxial structure.

16. A laser device comprising: a substrate having an off-angle greater than or equal to about 6 degrees (°); as well as an epitaxial structure located above the substrate, the epitaxial structure comprising a plurality of epitaxial layers; wherein the side walls of the laser device are parallel to each other, wherein the sidewalls are not perpendicular to the plurality of epitaxial layers, wherein the facets of the laser device are parallel to each other, and The facet of the laser device is perpendicular to the plurality of epitaxial layers. The laser device of claim 16 , wherein the cutting angle is less than about 15°.

18. The laser device of claim 16, wherein the cut angle is selected based on a refractive index contrast between a waveguide layer of the epitaxial structure and a cladding layer of the epitaxial structure. The laser device of claim 16 , wherein the facet has a parallelogram shape.

20. The laser device of claim 16, wherein the laser device has a fill factor of at least about 60%.

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