Vertical resonator optical parametric oscillator

Abstract

To provide a vertical resonator optical parametric oscillator. [Solution] In some embodiments, a vertical resonator optical parametric oscillator may be provided. The vertical resonator optical parametric oscillator may include a first mirror layer, a second mirror layer, and a nonlinear optical layer between the first and second mirror layers. The nonlinear optical layer may be configured to resonate both the fundamental harmonic optical signal and the second harmonic optical signal. Each of the first and second mirror layers may have a reflective surface for both the fundamental harmonic optical signal and the second harmonic optical signal to be reflected back and forth within the nonlinear optical layer.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the priority of U.S. Provisional Patent Application No. 63 / 740,151, filed on December 30, 2024, which is hereby incorporated by reference in its entirety.

[0002] The present disclosure relates to photonic integrated circuits, and more particularly, to vertical - cavity optical parametric oscillators.

Background Art

[0003] The emerging field of photonic integrated circuits requires parallel and reproducible device fabrication. In photonic integrated circuits, light is guided by waveguides, which are generally fabricated by etching millimeter - length and micrometer - width ridges from transparent oxides. Such fabricated waveguides operate as optical circuits that provide non - linear operation with low power budgets. However, conventional photonic integrated circuits still have several technical drawbacks. One major drawback is the low degree of connectivity because crossing waveguides generally result in large, undesirable crosstalk and cause power loss. Crossing waveguides are a problem for optical parametric oscillator solvers such as coherent - imaging machines and XY - machines where high - density arrays of non - linear optical elements need to be re - configured and connected to each other in a reconfigurable way. This limitation has been partially circumvented by relying on time - multiplexing where trains of optical pulses circulating within a given resonator encode different sites of a synthetic network. However, this solution sacrifices additional delay times for the optical solver and requires sophisticated electronic readout and feedback (e.g., using a large number of FPGAs). Furthermore, conventional photonic integrated circuits are generally bulky and limited to a footprint of about several cm due to waveguide bending losses, and thus face challenges with respect to large - scale and high - density integration. 2 of footprint, and thus face challenges with respect to large - scale and high - density integration.

Summary of the Invention

[0004] In some embodiments, a vertical cavity optical parametric oscillator may be provided. The vertical cavity optical parametric oscillator may include a first mirror layer, a second mirror layer, and a nonlinear optical layer between the first and second mirror layers. The nonlinear optical layer may be configured to resonate both the fundamental harmonic optical signal and the second harmonic optical signal. Each of the first and second mirror layers may have a reflective surface for both the fundamental harmonic optical signal and the second harmonic optical signal to be reflected back and forth within the nonlinear optical layer.

[0005] In some embodiments, a method for performing optical parametric oscillation may be provided. This method may include reflecting both the fundamental harmonic optical signal and the second harmonic optical signal back and forth within the nonlinear optical layer of the vertical resonator optical parametric oscillator by each of the first and second mirror layers of the vertical resonator optical parametric oscillator, such that both the fundamental harmonic optical signal and the second harmonic optical signal resonate within the nonlinear optical layer.

[0006] In some embodiments, a method for manufacturing a vertical resonator optical parametric oscillator may be provided. This method may include placing a first mirror layer on a substrate. This method may further include placing a nonlinear optical layer on the first mirror layer. This method may further include placing a second mirror layer on the nonlinear optical layer. The nonlinear optical layer may be configured to resonate both a fundamental harmonic optical signal and a second harmonic optical signal. Each of the first and second mirror layers may have a reflective surface for both the fundamental harmonic optical signal and the second harmonic optical signal to be reflected back and forth within the nonlinear optical layer. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows an exemplary vertical-cavity optical parametric oscillator according to an exemplary embodiment of the present disclosure. [Figure 2A]This figure shows an example of adjusting the nonlinear polarization generated within the nonlinear element of a vertical-cavity optical parametric oscillator according to an exemplary embodiment of the present disclosure. [Figure 2B] This figure shows another example of tuning the nonlinear polarization generated within the nonlinear element of a vertical resonator optical parametric oscillator, according to an exemplary embodiment of the present disclosure. [Figure 3A] This figure shows an example of the relative positioning of nonlinear elements between the resonator front mirror and the resonator back mirror of a vertical resonator optical parametric oscillator according to an exemplary embodiment of the present disclosure. [Figure 3B] This figure shows another example of the relative positioning of nonlinear elements between the resonator front mirror and the resonator back mirror of a vertical resonator optical parametric oscillator, according to an exemplary embodiment of the present disclosure. [Figure 4] This figure shows an exemplary vertical-cavity optical parametric oscillator array according to an exemplary embodiment of the present disclosure. [Figure 5] This figure shows an example of nearest-nearest coupling of a vertical optical parametric oscillator according to an exemplary embodiment of the present disclosure. [Figure 6] This figure shows an example of programmable coupling of a vertical optical parametric oscillator according to an exemplary embodiment of the present disclosure. [Figure 7] This is a flowchart illustrating an exemplary method for performing optical parametric amplification according to an exemplary embodiment of the present disclosure. [Figure 8] This is a flowchart illustrating an exemplary method for fabricating a vertical resonator optical parametric oscillator according to an exemplary embodiment of the present disclosure. [Modes for carrying out the invention]

[0008] The figures are for illustrative purposes only, but it should be understood that this disclosure is not limited to the arrangements and means shown in the drawings. In the figures, the same reference numerals identify elements that are at least generally similar.

[0009] Embodiments disclosed herein can provide vertical-cavity optical parametric oscillators. The disclosed vertical-cavity optical parametric oscillators may be free from the same connectivity issues (e.g., crossed waveguides) as conventional photonic integrated circuits, and can enable vertical injection and vertical readout of optical signals. That is, the need for horizontal transmission of optical signals, and therefore crossed waveguides, can be minimized. Additionally, vertical-cavity optical parametric oscillators have a smaller footprint compared to conventional photonic integrated circuits and are therefore suitable for large-scale production. For example, multiple vertical-cavity optical parametric oscillators can be fabricated on a single wafer. For example, because vertical-cavity optical parametric oscillators can enable vertical injection and readout of optical signals, there is also the possibility of out-of-plane networking for coherent optical computing with arbitrarily reconfigurable connectivity between components.

[0010] Figure 1 shows an exemplary vertical-cavity optical parametric oscillator 100 according to an exemplary embodiment of the present disclosure. As shown, the vertical-cavity optical parametric oscillator 100 may include, among several components, a resonator front mirror 104 with a reflective surface, a resonator back mirror 106 with another reflective surface, a nonlinear element 110, and a handle substrate 108. However, it should be understood that the components of the vertical-cavity optical parametric oscillator 100 shown in Figure 1 and described herein are merely examples, and optical resonators with additional, alternative, and fewer components should be considered within the scope of the present disclosure.

[0011] In some embodiments, each of the resonator front mirror 104 and the resonator back mirror 106 can be formed by coating the handle substrate 108. In some embodiments, the coating may be multilayered with alternating high-refractive-index and low-refractive-index materials. In some embodiments, the coating can be used to form a distributed Bragg reflector (DBR), and therefore each of the resonator front mirror 104 and the resonator back mirror 106 can be a DBR. Note that the terms “front” and “back” are used simply for ease of interpretation, and for example, the resonator front mirror 104 may face away from the handle substrate 108, and the resonator back mirror 106 may face the handle substrate, and should not be considered as specific orientations of the vertical resonator optical parametric oscillator 100.

[0012] The nonlinear element 110 can be formed from any type of material or crystal that can facilitate the nonlinear resonance of photons injected into the vertical-cavity optical parametric oscillator 100. Such nonlinear resonance allows the vertical-cavity optical parametric oscillator 100 to output photons of a different frequency than the injected photons. For example, the injected photons may be blue light, while the output photons are red light. In some embodiments, the nonlinear element can be formed using a second-order nonlinear optical element. In some embodiments, the second-order nonlinear element 110 can be thin-film lithium niobate (TFLN). The use of TFLN material is merely an example, and other second-order nonlinear optical materials should also be considered within the scope of this disclosure.

[0013] The handle substrate 108 can represent any type of substrate that can receive the resonator back mirror 106 (e.g., as a first coating layer), the nonlinear element 110 (e.g., as a second coating layer), and the resonator front mirror 104 (e.g., as a third coating layer) as coating layers. In some embodiments, the handle substrate 108 can form a wafer that can manufacture a number of vertical resonator parametric oscillator 100 devices using a number of coating layers.

[0014] For more efficient optical parametric oscillation, the vertical resonator optical parametric oscillator 100 can be configured to satisfy the following three conditions.

[0015] resonance The electromagnetic field within the vertical resonator optical parametric oscillator 100 may need to satisfy resonator resonance at both the fundamental harmonic (FH) frequency and the second harmonic (SH) frequency. As shown in the figure, both the FH field 112 (i.e., at the fundamental harmonic frequency) and the SH field 114 (i.e., at the second harmonic frequency) may need to resonate within the nonlinear element 110 based on reflections from the resonator front mirror 104 and the resonator back mirror 106, respectively. By performing excitation of either the FH field 112 or the SH field 114 (both resonant fields), the other field can be driven.

[0016] phase matching As they propagate through the nonlinear element 110, the FH field 112 and the SH field 114 may be out of phase due to the difference in refractive indices at their respective frequencies. For example, the nonlinear element 110 has a frequency-dependent refractive index, which can cause a phase shift between the FH field 112 and the SH field 114 as they repeatedly reflect and propagate. The vertical resonator optical parametric oscillator 100 can be configured to perform phase matching between the FH field 112 and the SH field 114 via the polarization of the nonlinear element 110. In some embodiments, the nonlinear element 110 may encompass the coherence lengths of both the FH field 112 and the SH field 114. In these cases, the nonlinear region within the nonlinear element 110 can be electrically inverted (also called "polarization processing") to adjust the nonlinear polarization generated within the nonlinear element 110 (i.e., increase the nonlinearity).

[0017] FIG. 2A shows an example of adjusting the nonlinear polarization generated within the nonlinear element 110 of the vertical cavity optical parametric oscillator 100 according to an exemplary embodiment of the present disclosure. As shown, a single nonlinear region 202 may be used to generate a single pole 204. The single pole 204 can represent a non-periodic polarization, and the non-periodic polarization can be used to maximize the nonlinear polarization because in the case of periodic polarization, the nonlinear effect from the previous pole may be canceled by the nonlinear effect from the subsequent pole. The non-periodic polarization can adjust the phase of one or more of the FH field 112 and the SH field 114. In some embodiments, periodic polarization may also be used. The phase adjustment can be used to bring the phase of the FH field 112 closer to the phase of the SH field 114 to cancel out the phase shift effect provided by the nonlinear element 110.

[0018] FIG. 2B shows another example of adjusting the nonlinear polarization generated within the nonlinear element 110 of the vertical cavity optical parametric oscillator 100 according to an exemplary embodiment of the present disclosure. As shown, two nonlinear regions 206, 208 may be electrically inverted to generate corresponding two poles 210, 212. Since the polarization patterns of the two poles 210, 212 do not repeat periodically, the two poles 210, 212 can represent a non-periodic polarization. Similar to the single pole 204 described above, the two non-periodic poles 210, 212 can also be used to maximize the nonlinear polarization. The non-periodic polarization can adjust the phase of one or more of the FH field 112 and the SH field 114. In some embodiments, periodic polarization may also be used. The phase adjustment can be used to bring the phase of the FH field 112 closer to the phase of the SH field 114 to cancel out the phase shift effect provided by the nonlinear element 110.

[0019] Relative phase of the second harmonic field The SH field 114 generated in the forward path through the non-linear element 110 can constructively interfere with the SH field 114 generated in the backward path after reflection from the resonator back mirror 106. If the interference is destructive, the SH fields 114 will cancel each other out, thereby reducing the usefulness of the vertical cavity optical parametric oscillator 100. Therefore, the non-linear element 110 with respect to the resonator front mirror 104 and the resonator back mirror 106 can be configured by adjusting the distance between the resonator front mirror 104 and the resonator back mirror 106, and the relative positioning of the non-linear element 110. The adjustment can be performed by using dielectric spacers (not shown) between the resonator front mirror 104 and the non-linear element 110, and / or between the resonator back mirror 106 and the non-linear element 110. The adjustment (performing the desired positioning of the non-linear element facing the resonator front mirror 104 and the resonator back mirror 106) can enable constructive interference of the forward and backward paths of the SH field 114, as will be described below.

[0020] FIG. 3A shows an example of the relative positioning of the non-linear element 110 between the resonator front mirror 104 and the resonator back mirror 106 according to an exemplary embodiment of the present disclosure. As shown, the FH field 112 and the SH field 114 may overlap within the non-linear element 110. Additionally, the SH field 114 can further constructively interfere within the non-linear element 110.

[0021] FIG. 3B shows another example of the relative positioning of the non-linear element 110 between the resonator front mirror 104 and the resonator back mirror 106 according to an exemplary embodiment of the present disclosure. As shown, the FH field 112 and the SH field 114 may overlap within the non-linear element 110. Additionally, the SH field 114 can further constructively interfere within the non-linear element 110.

[0022] Therefore, embodiments disclosed herein can achieve resonance within the vertical resonator optical parametric oscillator 100 by configuring the electrical domain to achieve phase matching and controlling the relative phase of the SH field 114 based on the relative positioning of the resonator front mirror 104, the resonator back mirror 106, and the nonlinear element 110. In some embodiments, additional configurability (or adjustment) may be achieved by temperature control. For example, a gold trace (not shown) may be incorporated into the vertical resonator optical parametric oscillator 100, and the current passing through the trace may generate heat, which may constitute the refractive index of the nonlinear element 110.

[0023] Configurations to achieve one or more of the resonance, phase matching, and relative phase of the SH field 114 can be realized using any type of manufacturing technique. For example, the desired resonance can be achieved by adjusting the length of the vertical resonator optical parametric oscillator 100. In some embodiments, the FH field 112 may be within the telecommunications wavelength (e.g., 1560 nm) and the SH field 114 may be within the infrared wavelength (e.g., 780 nm). The vertical resonator optical parametric oscillator 100 can be sized to a length of 10 micrometers to achieve resonance in both the telecommunications wavelength as the FH field 112 and the infrared wavelength as the SH field 114. Alternatively, the desired resonance can be achieved by increasing (or decreasing) the nonlinear element 110 to the desired thickness by using, for example, wafer bonding and wafer wrapping processes before closing the resonator with the resonator front mirror 104. The total resonator thickness, e.g., the thickness of the nonlinear element 110, can be calculated by the refractive index and reflection phase for the FH field 112 and the SH field 114. The reflection phase can be controlled by using different layered DBRs as one or more of the resonator back mirror 106 and the resonator front mirror 104.

[0024] In some embodiments, phase matching can be achieved by periodically polarizing the nonlinear element 110 along the resonator increasing direction using side electrodes, by wafer bonding the nonlinear crystal with alternating crystals, and / or by wafer bonding a nonlinear crystal thinner than the coherence length. In some embodiments, the desired relative phase of the SH field 114 can be achieved by using in-resonator dielectric spacers to hold the nonlinear element 110 in a desired position relative to the resonator front mirror 104 and the resonator back mirror 106.

[0025] Additionally, multiple vertical-cavity optical parametric oscillators 100 can be manufactured on a single wafer, thereby making the manufacturing process more efficient.

[0026] Figure 4 shows an exemplary vertical resonator optical parametric oscillator array 400 according to an exemplary embodiment of the present disclosure. As shown, the vertical resonator optical parametric oscillator array 400 can be formed on a handle substrate 108 forming a single wafer, and a number of vertical resonator optical parametric oscillators 100a to 100n can be formed. The vertical resonator optical parametric oscillator array 400 can be formed in a single manufacturing run by covering the handle substrate 108 with a number of layers, i.e., for each of the vertical resonator optical parametric oscillators 100a to 100n, a first layer 406 forming a resonator back mirror 106, a second layer 410 forming a nonlinear element 110, and a third layer 404 forming a resonator front mirror 104. In some embodiments, the manufacturing process can be modified to modify the covering for desired positioning of the nonlinear element 110 relative to the corresponding resonator front mirror 104 and resonator back mirror 106.

[0027] Each of the vertical resonator optical parametric oscillators 100a to 100n has a smaller footprint (e.g., μm). 2Because it has such a degree, a large, high-density array of vertical parametric oscillators 100a to 100n can be constructed as a nonlinear display surface. For example, the vertical resonator optical parametric oscillator array 400 can form a nonlinear display surface, and each of the vertical parametric oscillators 100a to 100n having the corresponding vertical radiation capability can become a pixel.

[0028] Figure 5 shows an example of nearest-neighbor coupling of vertical optical parametric oscillators according to an exemplary embodiment of the present disclosure. Three vertical optical parametric oscillators 500a, 500b, and 500c are shown for illustrative purposes only. Vertical optical parametric oscillator 500a may be nearest to vertical optical parametric oscillator 500b, and vertical optical parametric oscillator 500b may be nearest to vertical optical parametric oscillator 500c. Coupling may result from leakage of radiation to the nearest neighbor (forming the corresponding FH and SH fields), and vertical optical parametric oscillators 100a and 500b are coupled, resulting in a coupling term J 12 It is possible to form a coupling term J between the vertical optical parametric oscillator 500b and the vertical optical parametric oscillator 500c. 23 It may form.

[0029] Figure 6 shows an example of programmable coupling of vertical optical parametric oscillators according to an exemplary embodiment of the present disclosure. Programmable coupling allows vertical optical parametric oscillators to be coupled by directing the radiation of one vertical optical parametric oscillator to another vertical optical parametric oscillator using a free-space optical system, such as a mirror array 602. For example, the mirror array can direct the radiation of vertical optical parametric oscillator 600a to vertical optical parametric oscillator 600n (or vice versa), and the radiation of vertical optical parametric oscillator 600b to vertical optical parametric oscillator 600m. Enabling programmable coupling with a free-space optical system may eliminate the drawbacks of crossed waveguides in conventional photonic circuits.

[0030] Figure 7 shows a flowchart of an exemplary method 700 for performing optical parametric amplification according to an exemplary embodiment of the present disclosure. Optical parametric amplification can be performed by a vertical resonator optical parametric oscillator 100, as described with reference to Figure 1. In some embodiments, the vertical resonator optical parametric oscillator 100 may be part of a vertical resonator optical parametric oscillator array 400. The sequential enumeration of steps 710, 720 is for the sake of clarity, and steps 710, 720 may be performed simultaneously.

[0031] In step 710, each of the first and second mirror layers of the vertical resonator optical parametric oscillator 100 can reflect both the fundamental harmonic optical signal and the second harmonic optical signal back and forth within the nonlinear optical layer of the vertical resonator optical parametric oscillator.

[0032] In step 720, the nonlinear optical layer between the first mirror layer and the second mirror layer can resonate the fundamental harmonic optical signal and the second harmonic optical signal based on reflections by the first and second mirror layers. In some embodiments, the fundamental harmonic optical signal may be within the telecommunications frequency range (e.g., having a wavelength of 1560 nm), and the second harmonic optical signal may be within the infrared frequency range (e.g., having a wavelength of 780 nm).

[0033] Figure 8 shows a flowchart of an exemplary method 800 for fabricating a vertical resonator optical parametric oscillator according to an exemplary embodiment of the present disclosure. In some embodiments, the method 800 can be used to fabricate a vertical resonator optical parametric oscillator array 400, which includes a number of vertical resonator optical parametric oscillators 100.

[0034] In step 810, the first mirror layer can be placed on the substrate. The substrate can form a single wafer. In some embodiments, the first mirror layer may be formed by DBR.

[0035] In step 820, a nonlinear optical layer can be placed on the first mirror layer. In some embodiments, the nonlinear optical layer may be formed by a TFLN.

[0036] In step 830, a second mirror layer can be placed on the nonlinear optical layer. In some embodiments, the second mirror layer may also be formed by DBR.

[0037] Additional examples of embodiments of the methods and devices described herein are proposed by the structures and techniques described herein. Other non-limiting examples may be configured to operate separately or may be combined in any permutation or combination with any one or more of the other examples provided above or throughout this disclosure.

[0038] Those skilled in the art will recognize that this disclosure may be embodied in other specific forms without departing from its intent or essential features. Therefore, the embodiments currently disclosed are considered illustrative and not limiting in any way. The scope of this disclosure is indicated by the appended claims rather than the foregoing description, and all modifications that fall into their meaning, scope, and equivalents are intended to be incorporated herein.

[0039] It should be noted that the terms “including” and “comprising” should be interpreted as “including, but not limited to.” Unless explicitly stated in the claims, the term “a” should be interpreted as “at least one,” and “the,” “said,” etc., should be interpreted as “at least one,” “the aforementioned at least one,” etc. Furthermore, the applicant’s intent is that only claims containing the explicit language of “means for” or “step for” should be interpreted under 35 USC 112(f). Claims that do not explicitly contain the phrases “means for” or “step for” should not be interpreted under 35 USC 112(f). [Explanation of Symbols]

[0040] 100 Vertical resonator optical parametric oscillator 100a~100n Vertical resonator optical parametric oscillator, vertical parametric oscillator 104 Resonator Front Mirror 106 Resonator rearview mirror 108 Handle circuit board 110 Nonlinear elements 112 FH field 114 SH field 202 Single nonlinear domain 204 Single pole 206, 208 Two nonlinear regions 210, 212 Two poles 400 Vertical Cavity Optical Parametric Oscillator Array 404 Third Layer 406 First Layer 410 Second layer 500a, 500b, 500c Vertical Optical Parametric Oscillators 600a, 600b, 600m, 600n Vertical Optical Parametric Oscillators 602 Mirror Array J 12J 23 Combination term

Claims

1. A first mirror layer and a second mirror layer, The nonlinear optical layer between the first mirror layer and the second mirror layer A vertical resonator optical parametric oscillator including, The nonlinear optical layer is configured to resonate with both the fundamental harmonic optical signal and the second harmonic optical signal. A vertical-cavity optical parametric oscillator, wherein each of the first and second mirror layers comprises a reflective surface for both the fundamental harmonic optical signal and the second harmonic optical signal to be reflected back and forth within the nonlinear optical layer.

2. The vertical resonator optical parametric oscillator according to claim 1, wherein the nonlinear optical layer is formed of a thin film lithium niobate.

3. The vertical resonator optical parametric oscillator according to claim 1, wherein the length of the nonlinear optical layer is adjusted to resonate both the fundamental harmonic optical signal and the second harmonic optical signal.

4. The vertical resonator optical parametric oscillator according to claim 1, wherein the fundamental harmonic optical signal is within the telecommunications wavelength range and the second harmonic optical signal is within the infrared wavelength range.

5. The vertical resonator optical parametric oscillator according to claim 1, wherein the nonlinear optical layer is polarized to perform phase matching between the fundamental harmonic optical signal and the second harmonic optical signal.

6. The vertical resonator optical parametric oscillator according to claim 5, wherein the nonlinear optical layer is polarized aperiodically.

7. The vertical resonator optical parametric oscillator according to claim 1, wherein the nonlinear optical layer is configured to adjust the phase between different paths of the second harmonic optical signal.

8. The vertical resonator optical parametric oscillator according to claim 7, wherein the nonlinear optical layer is positioned at a predetermined location between the first mirror layer and the second mirror layer in order to adjust the phase between the different paths of the second harmonic optical signal.

9. The vertical resonator optical parametric oscillator according to claim 1, wherein at least one of the first mirror layer and the second mirror layer includes a distributed Bragg reflector.

10. The vertical resonator optical parametric oscillator according to claim 1, wherein at least one dimension of the vertical resonator optical parametric oscillator is about 10 micrometers.

11. A method for performing optical parametric oscillation, the method comprising reflecting both the fundamental harmonic optical signal and the second harmonic optical signal back and forth within the nonlinear optical layer of a vertical resonator optical parametric oscillator by a first mirror layer and a second mirror layer, respectively, such that both the fundamental harmonic optical signal and the second harmonic optical signal resonate within the nonlinear optical layer.

12. The method according to claim 11, wherein the nonlinear optical layer is formed of a thin film of lithium niobate.

13. The method according to claim 11, wherein the length of the nonlinear optical layer is adjusted to resonate both the fundamental harmonic optical signal and the second harmonic optical signal.

14. The method according to claim 11, wherein the fundamental harmonic optical signal is within the telecommunications wavelength range and the second harmonic optical signal is within the infrared wavelength range.

15. The polarization region within the nonlinear optical layer enables phase matching between the fundamental harmonic optical signal and the second harmonic optical signal. The method according to claim 11, further comprising:

16. The method according to claim 15, wherein the polarization region is polarized aperiodically.

17. The nonlinear optical layer adjusts the phase between different paths of the second harmonic optical signal. The method according to claim 11, further comprising:

18. The method according to claim 17, wherein the nonlinear optical layer is positioned at a predetermined location between the first mirror layer and the second mirror layer in order to adjust the phase between the different paths of the second harmonic optical signal.

19. A method for manufacturing a vertical resonator optical parametric oscillator, wherein the method is Placing the first mirror layer on the substrate, Placing a nonlinear optical layer on the first mirror layer, Placing a second mirror layer on the nonlinear optical layer Includes, The nonlinear optical layer is configured to resonate with both the fundamental harmonic optical signal and the second harmonic optical signal. A method wherein each of the first mirror layer and the second mirror layer comprises a reflective surface for both the fundamental harmonic optical signal and the second harmonic optical signal to be reflected back and forth within the nonlinear optical layer.

20. The method according to claim 19, wherein the nonlinear optical layer is formed of a thin film of lithium niobate.

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