Semi-conductor laser array with thin-layer lithium composite wave conductor

Abstract

A semiconductor laser arrangement comprises an array of surface-emitting lasers, each with a light-emitting surface and an opposing surface; at least one electrical contact, electrically connected to supply the array of surface-emitting lasers with an electrical bias from an external electrical source; and an optical waveguide over the light-emitting surface. The optical waveguide contains lithium.

Description

BACKGROUND1. Area

[0001] The present application relates generally to laser devices and, more particularly, to semiconductor laser devices. 2. Description of the state of the art

[0002] Visible light-emitting lasers, which emit light in the red-green-blue (RGB) spectrum, are widely used in medical applications such as tissue penetration for diagnosis and treatment. They are also used for projection in screens and displays (including AR / VR displays). Additionally, RGB lasers are used for applications requiring white light, such as spotlights. Consequently, compact RGB laser sources that can be mass-produced, such as VCSEL lasers, are highly sought after for RGB applications.

[0003] Currently, most available compact RGB solutions are based on LED sources. One drawback of current LED-based solutions is the lack of a white gamut for projectors / displays. Another disadvantage is the poor beam quality, which is detrimental in many medical applications. Furthermore, LEDs typically have a much wider divergence angle than lasers and, unlike lasers, lack coherence. Both of these characteristics lead to significant losses when the light energy is delivered to tissue. A further disadvantage of using LEDs is their lower modulation bandwidth, which is needed for applications requiring short pulse widths.

[0004] Currently available RGB laser technologies are significantly larger than VCSEL lasers. Gallium nitride-based RGB VCSEL lasers described in the literature have not proven sufficiently reliable and have low efficiencies.

[0005] Accordingly, experts are continuing their research and development in the field of semiconductor laser arrangements. SUMMARY

[0006] Semiconductor laser arrangements are revealed.

[0007] In one example, the semiconductor laser arrangement comprises an array of surface-emitting lasers with a light-emitting surface and an opposite surface; at least one electrical contact electrically coupled to the array of surface-emitting lasers to provide the array with an electrical bias from an external electrical source; and an optical waveguide over the light-emitting surface, the optical waveguide comprising lithium. The at least one electrical contact may comprise: one contact over the light-emitting surface and another contact over the opposite surface, or a pair of contacts over the opposite surface.

[0008] The optical waveguide can be made of lithium niobate or lithium tantalate. The optical waveguide can be periodically poled by 180°.

[0009] The array of surface-emitting lasers can comprise a variety of surface-emitting lasers with a vertical resonator or a variety of surface-emitting lasers with a photonic crystal. The array of surface-emitting lasers can include an upward-emitting laser or a downward-emitting laser.The array of surface-emitting lasers may include one or more of the following: an emitter designed to emit electromagnetic radiation or light with a wavelength between 1850 nm and 1950 nm; an emitter designed to emit electromagnetic radiation or light with a wavelength between 1200 nm and 1300 nm; an emitter designed to emit electromagnetic radiation or light with a wavelength between 1000 nm and 1100 nm; an emitter designed to emit electromagnetic radiation or light with a wavelength between 900 nm and 1000 nm; and an emitter designed to emit electromagnetic radiation or light with a wavelength between 1500 nm and 1600 nm.

[0010] The array of surface-emitting lasers can include at least one emitter with a polarization aligned with a width of the optical waveguide and / or at least one emitter with a polarization perpendicular to a width of the optical waveguide.

[0011] The semiconductor laser array can include a semi-insulating substrate positioned between the surface-emitting laser and the optical waveguide. The semi-insulating substrate can be made of gallium arsenide (GaAs). The semiconductor laser array can include an optical beam combiner positioned between the array of surface-emitting lasers and the optical waveguide. The semiconductor laser array can include an antireflection coating over the optical waveguide.

[0012] Methods for emitting electromagnetic radiation or light are also disclosed.

[0013] In one example, the method involves coupling a lithium-encompassing optical waveguide to a semiconductor laser and emitting electromagnetic radiation or light with a first wavelength from the semiconductor laser to the optical waveguide, wherein the electromagnetic radiation or light is emitted from the optical waveguide with a second wavelength and wherein the second wavelength is shorter than the first wavelength.

[0014] Coupling can involve binding or regrowth. In one example, emission can involve the emission of electromagnetic radiation or light with a wavelength between 1200 nm and 1300 nm from the semiconductor laser to the optical waveguide, with the frequency being doubled or substantially doubled as it passes through the optical waveguide.In another example, the emission may involve the emission of electromagnetic radiation or light with a first wavelength from a first emitter to an optical beam combiner, the emission of electromagnetic radiation or light with a second wavelength from a second emitter to the optical beam combiner, and the emission of the electromagnetic radiation or light with the first and second wavelengths from the beam combiner to the optical waveguide, which adds the first and second wavelengths as it passes through the optical waveguide.

[0015] Other examples will become clear from the following detailed description, the accompanying drawings and the attached patent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The disclosure will be described with reference to the following drawing figures, in which like reference numerals identify like parts throughout. Fig. 1 is a schematic cross-sectional view of an upward-directed or top-emitting semiconductor laser array; Fig. 2 is a schematic cross-sectional view of a downward-directed or downward-emitting semiconductor laser array; Fig. 3 is a schematic cross-sectional view of a downward-directed or downward-emitting semiconductor laser array; Fig. 4 is a schematic cross-sectional view of a portion of a semiconductor laser array; Fig. 5 is a schematic cross-sectional view of a portion of a semiconductor laser array; Fig. 6 is a schematic cross-sectional view of a portion of a semiconductor laser array; Fig. Figure 7 is a schematic cross-sectional view of a section of a semiconductor laser arrangement; and Fig. Figure 8 is a flowchart of a process for emitting electromagnetic radiation or light. DESCRIPTION

[0017] As used herein, spatial terms or directional designations such as "left," "right," "inner," "outer," "above," "below," and the like refer to the disclosure as depicted in the drawing figures. However, it is to be understood that the disclosure may take various alternative orientations and, accordingly, such terms are not to be considered limiting. Furthermore, as used herein, all numerical values ​​expressing dimensions, physical properties, processing parameters, component quantities, reaction conditions, and the like used in the description and claims are to be understood as being modified in all cases by the term "approximately" or "about." Accordingly, unless otherwise specified, the numerical values ​​presented in the following description and claims may vary depending on the desired properties sought by the present disclosure.At the very least, and not in an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical value is to be interpreted in light of the number of significant figures mentioned and by applying normal rounding procedures. Furthermore, all ranges disclosed herein are to be understood as encompassing the initial and final values ​​of the range and all subranges included therein. For example, a range mentioned as "1 to 10" is to be understood as including all subranges between (and including) the minimum value of 1 and the maximum value of 10, i.e., all subranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less, e.g., 1 to 3.3, 4.7 to 7.5, 5.5 to 10, and the like. "One" or "a" refers to one or more.

[0018] As used herein, “coupled,” “coupling,” and similar terms refer to two or more elements that are joined, linked, attached, connected, associated, or otherwise (e.g., mechanically, electrically, fluidically, optically, electromagnetically) connected to one another. In various examples, the elements may be directly or indirectly linked. As one example, element A may be directly linked to element B. As another example, element A may be indirectly linked to element B, for example, via another element C. It should be understood that not all links between the various disclosed elements are necessarily shown. Accordingly, there may also be links besides those shown in the figures.

[0019] As used herein, the phrase "at least one of" when used with an enumeration of elements means that various combinations of one or more of the enumerated elements may be used, and perhaps only one of each element in the enumeration is necessary. For example, "at least one of element A, element B, and element C" can include, without limitation, element A, or element A and element B. This example can also include element A, element B, and element C, or element B and element C. In other examples, "at least one of" can include, for example, without limitation, two of element A, one of element B, and ten of element C; four of element B and seven of element C; and other suitable combinations.

[0020] In one aspect, a semiconductor laser arrangement is disclosed herein. The semiconductor laser arrangement 100 can be used to emit light in the visible light spectrum, such as red, green, and / or blue (RGB) light. The disclosed semiconductor laser arrangement can feature visible light-emitting lasers (red, green, and blue) for use in various applications, such as medical applications for tissue penetration in diagnosis and treatment. The disclosed semiconductor laser arrangement can also be used for projection in screens and displays (including AR / VR displays). Additionally, the disclosed semiconductor laser arrangement can be used for applications requiring white light, such as headlights. The advantage of the disclosed semiconductor laser arrangement is that it is compact and can be manufactured in large quantities.

[0021] Several non-limiting examples are now described with reference to the accompanying figures, in which identical reference symbols correspond to identical or functionally equivalent elements.

[0022] The present disclosure features the use of vertical cavity surface-emitting lasers (VCSELs) or photonic crystal surface-emitting lasers (PCSELs) technology, for example, GaAs-based for high reliability and efficiency. In one example, the present disclosure uses an integrated RGB light source solution including a polarization-locked VCSEL and a thin-film lithium niobate (LiNbO3) optical waveguide. The LiNbO3 is poled by applying a very high bias voltage to temporarily placed electrodes attached to the sides of the waveguide 140. The periodicity of the poling can be such that the crystal structure is inverted when the number of generated photons has reached its maximum at a given point in the crystal.After polarization is complete, the periodically polarized thin-film LiNbO3 is transferred to the top of a VCSEL structure and vertically bound for an upward-emitting device and to the bottom of a VCSEL structure for a downward-emitting device (see . Fig. 1-3). While an optical waveguide 140 comprising LiNbO3 is described herein, the present disclosure is also applicable to an optical waveguide 140 comprising lithium tantalate (LiTaO3) instead of the optical waveguide 140 comprising LiNbO3.

[0023] The present disclosure uses a non-linear optical property of LiNbO3 to convert the VCSEL frequency into the visible spectrum. In a non-limiting example ( Fig. 4) Second harmonic generation can be used to frequency-double a 940 nm VCSEL to achieve blue lasers, to frequency-double a 1080 nm VCSEL to achieve green lasers, and to frequency-double a 1260 nm VCSEL to achieve red lasers. In another example, red lasers can be achieved by employing a frequency-addition generation property of LiNbO3 and using photons from 1060 nm and 1560 nm VCSEL sources (see Fig. 5) or from VCSEL sources at 940 nm and 1900 nm (see Fig. 6). In these designs, based on frequency addition generation, three or four laser sources can be used, depending on the exact optics implementation. The laser design (single / array) can be selected based on the power requirements of the intended application. Various color subsystems can be combined into a complete RGB solution using pick-and-place tools in the present disclosure.

[0024] To provide maximum frequency conversion efficiency, VCSEL light can be polarized in the direction of the LiNbO3 thickness. This can be achieved by implementing a polarization grating on or within the resonator of the VCSEL structure.

[0025] By co-designing the VCSEL structure with the LiNbO3 thin film (i.e., phase, field allocation optimization, beam shaping / focus), a high conversion efficiency as well as a high beam quality of the VCSEL can be maintained in the disclosed arrangement.

[0026] With reference to Fig. Figure 1, in a non-limiting example, features an upward-emitting semiconductor laser arrangement 100 comprising an array of surface-emitting lasers 110, each with a light-emitting surface 112 and an opposing surface 114. The array of surface-emitting lasers 110 can comprise any laser type required for the intended application. In one example, the array of surface-emitting lasers 110 includes a variety of VCSELs. In another example, the array of surface-emitting lasers 110 includes a variety of PCSELs.

[0027] The Fig. Figure 1 shows an upward-emitting semiconductor laser arrangement 100 comprising a first contact layer 120 on the underside, on or above the opposite surface 114, and a second contact layer 130 on the top side, on or above the light-emitting surface 112. The first and second contact layers 120 and 130 can be configured, in a manner known in the art, to allow an electrical bias to be applied to the emitters 116 (in the Fig. 4-7) of the array of surface-emitting lasers 110 from an external electrical source to cause the array of surface-emitting lasers 110 to output or emit laser light 170 in an upward direction, also in a manner known in the art. Each of the first and second contact layers 120 and 130 may be of a suitable and / or desirable thickness for a desired current density for the application and may be composed of any suitable and / or desirable electrically conductive material or compound, for example, without limitation, gold-germanium (AuGe) for an n-type contact or titanium-platinum-gold (TiPtAu) for a p-type contact.

[0028] With reference to the Fig. 2 and Fig. 3. The exemplary downward-emitting semiconductor laser arrangements 100, which are in the Fig. 2 and Fig. Figure 3 shows a pair of spaced-apart second contact layers 130 on the top surface on or above the opposite surface 114, which, in these figures, is the surface of the lower emitting semiconductor laser arrays 100. The downward-emitting semiconductor laser arrays 100, which are shown in the Fig. 2 and Fig. Figure 3 shows no first contact layer 120, as shown in Fig. 1 shown, on their undersides, to avoid interference through such a contact layer when emitting laser light 170 over the undersides in a manner known in the art.

[0029] The pair of second contact layers 130 on the top side of the opposite, or upper, surfaces 114 of the downward-emitting semiconductor laser arrangements 100, which are located in the Fig. 2 and Fig. The components shown in Figure 3 can be designed, in a manner known in engineering, to allow an electrical bias voltage to be applied to the emitters 116 (in the Fig. 4-7 shown) of the array of surface-emitting lasers 110 in the Fig. 2 and Fig. 3 is applied from an external electrical source to cause the array of surface-emitting lasers 110 to emit or emit laser light 170 in a downward direction, also in a manner known in the art. Each contact layer 130 in the Fig. 2 and Fig. 3 can be of any suitable and / or desirable thickness for a desired current density for the application and can consist of any suitable and / or desirable electrically conductive material or compound, for example, without limitation: gold germanium (AuGe) for an n-type contact or titanium platinum gold (TiPtAu) for a p-type contact.

[0030] As in the Fig. 1-7, the semiconductor laser assembly 100 further includes an optical waveguide 140 coupled to a light emission direction side of the light-emitting surface 112. In one example, the optical waveguide 140 comprises lithium. In one non-limiting example, the optical waveguide 140 comprises lithium niobate, which offers desirable nonlinear optical properties enabling frequency doubling. It should be understood that other materials or compounds with nonlinear optical properties comparable to those of lithium niobate may be implemented. For example, the optical waveguide may comprise lithium tantalate or other lithium or non-lithium materials or compounds with comparable optical properties. In one example, the optical waveguide 140 is a thin-film lithium niobate waveguide.

[0031] As in the Fig. As shown in Figures 1-3, the optical waveguide 140 of the semiconductor laser arrangement 100 can be periodically polarized multiple times. For example, the optical waveguide 140 can be periodically polarized at approximately 180°. In the [reference to the figure] Fig. In the example illustrated in Figures 1-3, the optical waveguide 140 can be periodically poled eight times or eight periods with pole angles of 0° and 180° (or 180° and 0°). However, this is not to be interpreted in a limiting sense, as the number of times or periods the optical waveguide 140 can be periodically poled and the pole angles can be selected by one skilled in the art for a particular application. The use of a periodically poled thin-film lithium niobate optical waveguide 140 provides an efficient medium for nonlinear wavelength conversion processes, such as frequency doubling. The semiconductor laser assembly 100 can include a coating 124, such as an anti-reflection coating, on a surface of the optical waveguide 140 opposite the array of surface-emitting lasers 110.

[0032] With reference to the Fig. 4-7 The array of surface-emitting lasers 110 of the semiconductor laser arrangement 100 can have a plurality of emitters 116 designed to emit electromagnetic radiation or light with different wavelengths. In some non-limiting examples, the array of surface-emitting lasers 110 can include at least one emitter 116A designed to emit electromagnetic radiation or light with a wavelength between 1200 nm and 1300 nm. In another example, the array of surface-emitting lasers 110 can include at least one emitter 116B designed to emit electromagnetic radiation or light with a wavelength between 1000 nm and 1100 nm.In another example, the array of surface-emitting lasers 110 can include at least one emitter 116C designed to emit electromagnetic radiation or light with a wavelength between 900 nm and 1000 nm. In another example, the array of surface-emitting lasers 110 can include at least one emitter 116D designed to emit electromagnetic radiation or light with a wavelength between 1000 nm and 1100 nm. In yet another example, the array of surface-emitting lasers 110 can include at least one emitter 116E designed to emit electromagnetic radiation or light with a wavelength between 1500 nm and 1600 nm.In yet another example, the array of surface-emitting lasers 110 can include at least one emitter 116F designed to emit electromagnetic radiation or light with a wavelength between 1850 nm and 1950 nm.

[0033] With reference to Fig. 7 The disclosed semiconductor laser arrangement 100 can have a plurality of emitters 116 with different polarizations. In the example of Fig. Figure 7 shows that the array of surface-emitting lasers 110 comprises four emitters 116. Some emitters 116b in the array may have a polarization aligned with the width of the optical thin-film waveguide 140. Light from these emitters will result in the output of the optical thin-film waveguide 140 at twice the frequency. Other emitters 116a in the array may have a polarization aligned perpendicular to the width of the optical thin-film waveguide 140. Light from the emitters 116a is not affected by the non-linear effect in the optical thin-film waveguide 140, and the output wavelength will remain the same as the input wavelength (for example, IR). The polarization blocking for the emitter can be defined by the photonic crystal design in a PCSEL array or by the lattice orientation in a VCSEL array. Accordingly, as in the example of Fig. Figure 7 shows that the array of surface-emitting lasers 110 has at least one emitter 116a having a polarization that is aligned with a width of the optical waveguide 140 and / or at least one emitter 116b having a polarization that is perpendicular to a width of the optical waveguide 140.

[0034] With reference to Fig. In one example, the semiconductor laser arrangement 100 can have one or more dielectric layers 150 and 151. In another example, the dielectric layer 151 can be positioned between the array of surface-emitting lasers 110 and the optical waveguide 140. In another example, the dielectric layer 151 can comprise an index-matching dielectric. In another example, the index-matching dielectric comprising the dielectric layer 151 can have a refractive index that is the square of an index n1 of the array of surface-emitting lasers 110 times an index n2 of the optical waveguide 140, i.e., (n1 x n2) 2 . The dielectric layer 150 on the remaining surface 112 surrounding the optical waveguide 140 may be a passivation layer, for example, silicon nitride, which prevents moisture and / or other undesirable contaminants from coming into contact with the remaining surface 112.

[0035] With reference to Fig. In one example, the semiconductor laser arrangement 100 can include a semi-insulating substrate 160 positioned between the surface-emitting laser 110 and the optical waveguide 140. The semi-insulating substrate 160 can be made of any material that possesses the required insulating material properties. For example, the semi-insulating substrate 160 can be gallium arsenide (GaAs).

[0036] With reference to Fig. In one example, the semiconductor laser arrangement 100 can include an optical beam combiner 180 positioned between the array of surface-emitting lasers 110 and the optical waveguide 140. In another example, an optical beam combiner 180 can be located between the emitters 116D and 116E in Fig. 5. In one example, the optical beam combiner 180 delivers the electromagnetic radiation or light emitted by the emitters 116D and 116E with wavelengths of, for example, 1060 nm (corresponding to a frequency f1 of approximately 943 kHz) and 1560 nm (corresponding to a frequency f2 of approximately 641 kHz), respectively, to the optical waveguide 140, which is positioned on the optical beam combiner 180. In this example, the optical waveguide 140 adds these frequencies f1 and f2 to obtain an electromagnetic output radiation or light with a wavelength of approximately 630 nm (corresponding to a frequency f3 of approximately 1590 kHz), which corresponds to the color red. In the exemplary semiconductor laser arrangement 100, which is shown in Fig. As shown in Figure 5, emitter 116C is positioned directly beneath an optical waveguide 140, without an intervening optical combiner 180, and emitter 116B is also positioned directly beneath an optical waveguide 140, likewise without an intervening optical combiner 180. In this disclosure, because the values ​​of the frequencies and wavelengths are rounded to three or four decimal places, with all subsequent decimal places omitted, the value of each frequency and / or wavelength can be described, without limitation, as "about" a certain value. However, this is not to be interpreted as a limitation.

[0037] With reference to Fig. 8 also discloses a method 200 for emitting electromagnetic radiation or light 170, as in the Fig. Figures 4-7 illustrate the method 200, which can be used with a VCSEL or PCSEL array. In one example, the method 200 can involve coupling 220 an optical lithium niobate waveguide 140 to an array of surface-emitting lasers 110. In another example, the coupling 220 can involve binding the optical waveguide 140 to the array of surface-emitting lasers 110 either directly, as shown in Fig. 3 shown, or via the semi-insulating substrate 160, as in Fig. 2 shown. In another example, the coupling 220 can exhibit the regrowth of the optical waveguide 140 on a surface of the array of surface-emitting lasers 110.

[0038] In one example, the method 200 can include coupling 220 to achieve a semiconductor laser arrangement 100 with an array of surface-emitting lasers 110 having a light-emitting surface 112 and an opposite surface 114. The array of surface-emitting lasers 110 can comprise any type of wavelength or laser required for the intended application. In one example, the array of surface-emitting lasers 110 includes a variety of vertical resonator surface-emitting lasers (VCSELs). In another example, the array of surface-emitting lasers 100 can comprise a variety of photonic crystal surface-emitting lasers (PCSELs).

[0039] In one example, the semiconductor laser array 100 shown in Fig. 1 and formed by method 200, may include a first contact layer 120 on the bottom surface on or above the opposite (bottom) surface 114 and a second contact layer 130 on the top surface on or above a part or portion of the light-emitting surface 112. Each contact layer 120 and 130 may be of any suitable and / or desirable thickness for a desired current density for the application and may be composed of any suitable and / or desirable electrically conductive material or compound, for example, without limitation: gold-germanium (AuGe) for an n-type contact or titanium-platinum-gold (TiPtAu) for a p-type contact.

[0040] In another example, the semiconductor laser arrangement 100, which is in the Fig. 2 and Fig. Figure 3, formed by method 200, comprises a pair of spaced-apart contact layers 130 on or over portions or sections of the opposite (upper) surface 114 and no contact on the underside. Each contact layer 130 can be of any suitable and / or desirable thickness for a desired current density for the application and can consist of any suitable and / or desirable electrically conductive material or compound, for example, without limitation: gold-germanium (AuGe) for an n-type contact or titanium-platinum-gold (TiPtAu) for a p-type contact.

[0041] As in the Fig. As shown in Figures 1-7, the semiconductor laser arrangement 100 formed by the method 200 can form an optical waveguide 140 on or above an upward-facing light-emitting surface 112 (in Fig. 1) or on or below a downward-facing light-emitting surface 112 (in the Fig. 2 and Fig. 3) possess the capacity to receive electromagnetic radiation or light emitted by the array of surface-emitting lasers 110. For example, since Fig. 1 illustrates a top-emitting semiconductor laser array 100, the optical waveguide 140 is positioned on the light-emitting surface 112, which emits electromagnetic radiation or light upwards in the figure. In another example, since the Fig. 2 and Fig. Figure 3 shows downward-emitting semiconductor laser arrays 100, the optical waveguides 140 positioned on or below the light-emitting surfaces 112, which emit electromagnetic radiation or light downwards in the figures. Herein, the terms "electromagnetic radiation", "light", and "laser light" may be used synonymously with regard to the emission of electromagnetic radiation, light, or laser light from a surface-emitting laser or the array of surface-emitting lasers 110.

[0042] In one example, the optical waveguide 140 comprises lithium. In a non-limiting example, the optical waveguide 140 may comprise lithium niobate, which provides desirable nonlinear optical properties, enabling frequency doubling of a single wavelength electromagnetic radiation or light (of frequency f1) propagating through the optical waveguide 140, or, when the optical waveguide 140 is used with the optical beam combiner 180, which provides two different wavelengths of electromagnetic radiation or light (of frequencies f1 and f2) to the optical waveguide 140, the optical waveguide 140 emits electromagnetic radiation or light having a frequency of f3, which is the sum of the frequencies f1 and f2, i.e., f3 = f1 + f2.It is understood that other materials with non-linear optical properties comparable to those of lithium niobate can be implemented. For example, optical waveguide 140 can be made of lithium tantalate or other lithium or non-lithium materials with comparable optical properties. In one example, optical waveguide 140 is a thin-film lithium niobate waveguide.

[0043] As in the Fig. As shown in Figures 1-3, the optical waveguide 140 of the semiconductor laser array 100 formed by method 200 can be periodically polarized. In one example, the optical waveguide 140 is periodically polarized at approximately 180°. The use of a periodically polarized lithium niobate thin-film optical waveguide 140 provides an efficient medium for non-linear wavelength conversion processes, such as frequency doubling of the frequency of a single-wavelength electromagnetic radiation or light input into the optical waveguide 140, or adding the frequencies of at least two wavelengths of the electromagnetic radiation or light input into the optical waveguide 140, e.g., from an optical beam combiner 110. The semiconductor laser array 100 can have a coating 124, such as an antireflection coating, on a surface of the optical waveguide 140 facing the array of surface-emitting lasers 110.

[0044] With reference to the Fig. 4-7, the semiconductor laser assembly 100 formed by the method 200 may include an array of surface-emitting lasers 110 having a plurality of emitters 116 configured to emit electromagnetic radiation or light having different wavelengths. In one example, the array of surface-emitting lasers 110 may include at least one emitter 116A configured to emit electromagnetic radiation or light having a wavelength between 1200 nm and 1300 nm. In another example, the array of surface-emitting lasers 110 may include at least one emitter 116B configured to emit electromagnetic radiation or light having a wavelength between 1000 nm and 1100 nm.In another example, the array of surface-emitting lasers 110 can include at least one emitter 116C designed to emit electromagnetic radiation or light with a wavelength between 900 nm and 1000 nm. In another example, the array of surface-emitting lasers 110 can include at least one emitter 116D designed to emit electromagnetic radiation or light with a wavelength between 1000 nm and 1100 nm. In yet another example, the array of surface-emitting lasers 110 can include at least one emitter 116E designed to emit electromagnetic radiation or light with a wavelength between 1500 nm and 1600 nm.In yet another example, the array of surface emitting lasers 110 may include at least one emitter 116F configured to emit electromagnetic radiation or light having a wavelength between 1850 nm and 1950 nm.

[0045] The array of surface emitting lasers 110 in the Fig. 4-7, electromagnetic radiation or laser light 170 is shown emitting in an upward direction, e.g., when used with the Fig. 1 is used. However, it should be understood that the array of surface-emitting lasers 110 in one of the Fig. 4-7 (i.e., with the thin-film optical waveguides 140 under the emitters 116), wherein the array of surface-emitting lasers 110 emits electromagnetic radiation or laser light 170 in a downward direction, e.g., when used with the semiconductor laser arrays 100 shown in the Fig. 2 and Fig. 3 are shown.

[0046] With reference to Fig. 7, the disclosed semiconductor laser arrangement 100 formed by the method 200 may include a plurality of emitters 116 with different polarizations. In the example of Fig. 7, the array of surface-emitting lasers 110 may comprise four emitters 116. Some emitters 116b in the array may have a polarization that is based on the width in Fig. 7, of the optical thin-film waveguide 140 is aligned. Light from these emitters 116b will result in a frequency twice that of the optical thin-film waveguide 140 at its output. Other emitters 116a in the array may have a polarization perpendicular to the width, e.g., vertically in Fig. 7, of the thin-film optical waveguide 140. Light from these emitters 116a is not affected by the nonlinear effect of the thin-film optical waveguide 140, and the wavelength will remain the same as the input wavelength (e.g., IR). The polarization blocking for each emitter can be defined by the photonic crystal design for a PCSEL array or by the grating alignment for a VCSEL array. Accordingly, as in the example of Fig. Figure 7 shows that the array of surface-emitting lasers 110 has at least one emitter 116a having a polarization aligned with a width of the optical waveguide 140, and / or at least one emitter 116b having a polarization perpendicular to a width of the optical waveguide 140.

[0047] With reference to Fig. In one or more examples, the semiconductor laser arrangement 100 formed by method 200 can include a semi-insulating substrate 160 positioned between the surface-emitting laser 110 and the optical waveguide 140. The semi-insulating substrate 160 can be made of any material that has the required insulating material properties. In one example, the semi-insulating substrate 160 can be gallium arsenide (GaAs).

[0048] With reference to the Fig. 5 and Fig. 6, in one or more examples, the semiconductor laser arrangement 100 formed by method 200 can include an optical beam combiner 180 positioned between two or more emitters 116 of the array of surface-emitting lasers 110 and a single optical waveguide 140. The optical beam combiner 180 of Fig. 6 can directly transmit electromagnetic radiation or light (of frequency f1) emitted by the emitter 116C to the optical waveguide 140, which is positioned on or above the emitter 116C. In the manner described above, the optical waveguide 140, which is positioned on or above the emitter 116C, doubles the frequency of the electromagnetic radiation or light emitted directly by the emitter 116C to the optical waveguide 140. Additionally, the optical beam combiner 180 can Fig. 6. Electromagnetic radiation or light (of frequency f1) emitted by emitter 116C is directed or guided to optical waveguide 140, which is positioned on or above emitter 116F. Optical waveguide 140, positioned on or above emitter 116F, also receives electromagnetic radiation or light (of frequency f2) emitted by emitter 116F. In the manner described above, optical waveguide 140, positioned on or above emitter 116F, adds the frequencies (f1 and f2) of the electromagnetic radiation or light received by optical waveguide 140 from emitters 116C and 116F and emits electromagnetic radiation or light 170 with a frequency f3, which is the sum of the frequencies f1 and f2, i.e., f3 = f1 + f2.

[0049] With reference to Fig.8. Method 200 can involve the emission 230 of electromagnetic radiation or light with a first wavelength from the semiconductor laser arrangement 100 to the optical waveguide 140. The electromagnetic radiation or light with the first wavelength is then subsequently emitted by the optical waveguide 140 with a second wavelength. In one example, the second wavelength can be shorter than the first wavelength. For instance, the output frequency of the second wavelength can be doubled such that the output wavelength is approximately half the length of the input wavelength. In another example, the second wavelength can be approximately half the length of the first wavelength.

[0050] Emitting 230 of method 200 may include emitting electromagnetic radiation or light in the visible RGB light spectrum. Accordingly, in one example, emitting 230 may include emitting electromagnetic radiation or light having a wavelength between 1200 nm and 1300 nm from an emitter 116 of semiconductor laser array 100 to an optical waveguide 140 such that the frequency is substantially doubled upon passing through optical waveguide 140.

[0051] Emitting 230 of method 200 may further comprise combining (adding) electromagnetic radiation or light emitted at two or more different central wavelengths to result in a different output wavelength. For example, emitting 230 may comprise emitting electromagnetic radiation or light having a first wavelength (corresponding to a first frequency f1), for example, a wavelength between 1000 nm and 1100 nm, from a first emitter 116D to an optical beam combiner 180 and simultaneously emitting electromagnetic radiation or light having a second wavelength (corresponding to a second frequency f2), for example, a wavelength between 1500 nm and 1600 nm, from a second emitter 116E to the optical beam combiner 180.The optical beam combiner 180 directs the electromagnetic radiation or light with the first and second wavelengths (and thus the first and second frequencies f1 and f2) to the optical waveguide 140, which is coupled to the optical beam combiner 180. The optical waveguide 140 then outputs or emits the electromagnetic radiation or light 170 with a frequency f3, which is the sum of the frequencies f1 and f2, i.e., f3 = f1 + f2. In the example mentioned above, the first and second wavelengths, the first and second frequencies f1 and f2, and the frequency f3, and thus the wavelength of the emitted electromagnetic radiation or light 170, differ from the first and second frequencies f1 and f2 and the first and second wavelengths.It should be understood that the above-mentioned examples of wavelengths and frequencies are merely exemplary and that any two or more center wavelengths input to an optical beam combiner 180 are directed to and summed by the optical waveguide 140 coupled to the optical beam combiner 180.

[0052] In one or more examples, method 200 may include poling 210 a lithium niobate thin film to form a periodically poled optical waveguide with 180° periodically reversed domains. In one example, poling 210 includes coupling a plurality of electrodes to the lithium niobate layer and applying appropriate electrical bias voltage(s) to the electrodes to achieve a periodically poled optical waveguide 140.

[0053] Other non-limiting examples or aspects of this revelation are presented in the following illustrative and exemplary numbered provisions.

[0054] Definition 1: Semiconductor laser arrangement comprising: an array of surface-emitting lasers having a light-emitting surface and an opposing surface; at least one electrical contact electrically coupled to provide the array of surface-emitting lasers with an electrical bias from an external electrical source; and an optical waveguide over the light-emitting surface, wherein the optical waveguide comprises lithium.

[0055] Definition 2: Semiconductor laser arrangement according to Definition 1, wherein the at least one electrical contact may have one contact over the light-emitting surface and another contact over the opposite surface or a pair of contacts over the opposite surface.

[0056] Clause 3: A semiconductor laser device according to clause 1 or 2, wherein the optical waveguide may comprise lithium niobate.

[0057] Clause 4: A semiconductor laser device according to any one of clauses 1-3, wherein the optical waveguide may comprise lithium tantalate.

[0058] Provision 5: A semiconductor laser device according to any one of provisions 1-4, wherein the optical waveguide may be periodically poled 180°.

[0059] Provision 6: Semiconductor laser arrangement according to any of Provisions 1-5, wherein the array of surface-emitting lasers may comprise a plurality of surface-emitting lasers with a vertical resonator or a plurality of surface-emitting lasers with a photonic crystal.

[0060] Provision 7: Semiconductor laser arrangement according to any of Provisions 1-6, wherein the array of surface-emitting lasers comprises upward-emitting lasers or downward-emitting lasers.

[0061] Provision 8: Semiconductor laser arrangement according to any of Provisions 1-7, wherein the array of surface-emitting lasers comprises at least one emitter designed to emit electromagnetic radiation with a wavelength between 1850 nm and 1950 nm.

[0062] Provision 9: Semiconductor laser arrangement according to any of Provisions 1-8, wherein the array of surface-emitting lasers comprises at least one emitter designed to emit electromagnetic radiation with a wavelength between 1200 nm and 1300 nm.

[0063] Provision 10: Semiconductor laser arrangement according to any of provisions 1-9, wherein the array of surface-emitting lasers comprises at least one emitter designed to emit electromagnetic radiation with a wavelength between 1000 nm and 1100 nm.

[0064] Provision 11: Semiconductor laser arrangement according to any of Provisions 1-10, wherein the array of surface-emitting lasers comprises at least one emitter designed to emit electromagnetic radiation with a wavelength between 900 nm and 1000 nm.

[0065] Provision 12: Semiconductor laser arrangement according to any of Provisions 1-11, wherein the array of surface-emitting lasers comprises at least one emitter designed to emit electromagnetic radiation with a wavelength between 1500 nm and 1600 nm.

[0066] Provision 13: Semiconductor laser arrangement according to one of Provisions 1-12, wherein the array of surface-emitting lasers comprises at least one emitter with a polarization aligned to a width of the optical waveguide.

[0067] Provision 14: Semiconductor laser arrangement according to one of Provisions 1-13, wherein the array of surface-emitting lasers comprises at least one emitter with a polarization perpendicular to a width of the optical waveguide.

[0068] Definition 15: Semiconductor laser arrangement according to one of Definitions 1-14, further comprising a semi-insulating substrate positioned between the surface-emitting laser and the optical waveguide.

[0069] Determination 16: Semiconductor laser arrangement according to one of Determinations 1-15, wherein the semi-insulating substrate comprises gallium arsenide (GaAs).

[0070] Provision 17: Semiconductor laser arrangement according to one of Provisions 1-16, further comprising an optical beam combiner positioned between the surface-emitting lasers and the optical waveguide.

[0071] Provision 18: Semiconductor laser arrangement according to one of provisions 1-17, further comprising an antireflection coating over the optical waveguide.

[0072] Provision 19: A method of emitting electromagnetic radiation, the method comprising: coupling an optical waveguide comprising lithium to a semiconductor laser and emitting electromagnetic radiation having a first wavelength from the semiconductor laser to the optical waveguide, wherein the electromagnetic radiation is emitted from the optical waveguide at a second wavelength, and wherein the second wavelength is shorter than the first wavelength.

[0073] Determination 20: Procedure according to Determination 19, wherein the second wavelength is approximately half the size of the first wavelength.

[0074] Provision 21: Procedure according to Provision 19 or 20, wherein coupling includes binding or regrowth.

[0075] Provision 22: Method according to any of Provisions 19-21, wherein the emission comprises the emission of electromagnetic radiation having a wavelength between 1200 nm and 1300 nm from the semiconductor laser to the optical waveguide, wherein the frequency is doubled or substantially doubled as it passes through the optical waveguide.

[0076] Provision 23: The method of any one of provisions 19-22, wherein emitting comprises: emitting electromagnetic radiation having the first wavelength from a first emitter of the semiconductor laser to an optical beam combiner; emitting electromagnetic radiation having a second wavelength from a second emitter of the semiconductor laser to the optical beam combiner; and emitting the electromagnetic radiation having the first and second wavelengths from the optical beam combiner to the optical waveguide that adds the first and second frequencies associated with the first and second wavelengths upon passing through the optical waveguide.

[0077] Provision 24: Method according to one of Provisions 19-23, wherein: the first wavelength is between 900 nm and 1000 nm and the second wavelength is between one of: (1) 900 nm and 1000 nm or (2) 1850 nm and 1950 nm.

[0078] Provision 25: A method according to any one of provisions 19-24, further comprising poling a lithium niobate or lithium tantalate thin film to obtain a periodically poled optical waveguide having 180° periodically inverted domains.

[0079] Although various examples of the disclosed semiconductor laser device have been illustrated and described, modifications may occur to those skilled in the art upon reading the specification. This application incorporates such modifications and is limited only by the scope of the claims.

Claims

[1] Semiconductor laser arrangement, comprising: an array of surface-emitting lasers having a light-emitting surface and an opposing surface; at least one electrical contact electrically connected to provide the array of surface-emitting lasers with an electrical bias from an external electrical source; and an optical waveguide over the light-emitting surface, the optical waveguide comprising lithium. [2] A semiconductor laser device according to claim 1, wherein the at least one electrical contact comprises: one contact over the light-emitting surface and another contact over the opposite surface, or a pair of contacts above the opposite surface. [3] A semiconductor laser device according to claim 1 or 2, wherein the optical waveguide comprises lithium niobate or lithium tantalate. [4] A semiconductor laser device according to any one of the preceding claims, wherein the optical waveguide is periodically poled 180°. [5] A semiconductor laser array according to any preceding claim, wherein the array of surface emitting lasers comprises a plurality of vertical cavity surface emitting lasers or a plurality of photonic crystal surface emitting lasers. [6] A semiconductor laser array according to any preceding claim, wherein the array of surface emitting lasers comprises top emitting lasers or bottom emitting lasers. [7] Semiconductor laser arrangement according to one of the preceding claims, wherein the array of surface-emitting lasers comprises at least one emitter designed to emit electromagnetic radiation having a wavelength between 1850 nm and 1950 nm, having a wavelength between 1200 nm and 1300 nm, having a wavelength between 1000 nm and 1100 nm, having a wavelength between 900 nm and 1000 nm or having a wavelength between 1500 nm and 1600 nm. [8] A semiconductor laser array according to any preceding claim, wherein the array of surface emitting lasers comprises at least one emitter having a polarization aligned with a width of the optical waveguide. [9] A semiconductor laser array according to any one of claims 1-7, wherein the array of surface emitting lasers comprises at least one emitter with a polarization perpendicular to a width of the optical waveguide. [10] A semiconductor laser device according to any one of the preceding claims, further comprising a semi-insulating substrate positioned between the surface emitting laser and the optical waveguide. [11] A semiconductor laser device according to claim 10, wherein the semi-insulating substrate comprises gallium arsenide (GaAs). [12] A semiconductor laser array according to any preceding claim, further comprising an optical beam combiner positioned between the surface emitting lasers and the optical waveguide. [13] A semiconductor laser device according to any one of the preceding claims, further comprising an anti-reflection coating over the optical waveguide. [14] A method for emitting electromagnetic radiation, the method comprising: Coupling a lithium-containing optical waveguide to a semiconductor laser, and Emitting electromagnetic radiation having a first wavelength from the semiconductor laser to the optical waveguide, wherein the electromagnetic radiation is emitted from the optical waveguide at a second wavelength, and wherein the second wavelength is shorter than the first wavelength. [15] The method of claim 14, wherein the second wavelength is approximately half the first wavelength. [16] A method according to claim 14 or 15, wherein the coupling comprises binding or regrowth. [17] A method according to any one of claims 14-16, wherein emitting comprises emitting electromagnetic radiation having a wavelength between 1200 nm and 1300 nm from the semiconductor laser to the optical waveguide, the frequency being doubled or substantially doubled upon passing through the optical waveguide. [18] A method according to any one of claims 14 to 16, wherein emitting comprises: Emitting electromagnetic radiation having a first wavelength from a first emitter of the semiconductor laser to an optical beam combiner, Emitting electromagnetic radiation having a second wavelength from a second emitter of the semiconductor laser to an optical beam combiner, and Emitting the electromagnetic radiation having the first and second wavelengths from the optical beam combiner to the optical waveguide, which adds the first and second wavelengths as they pass through the optical waveguide. [19] The method of claim 18, wherein: the first wavelength is between 900 nm and 1000 nm, and the second wavelength is between one of: (1) 900 nm and 1000 nm or (2) 1850 nm and 1950 nm. [20] The method of any one of claims 14-19, further comprising poling a lithium niobate or lithium tantalate thin film to obtain a periodically poled optical waveguide having 180° periodically inverted domains.

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