A monolithic heterogeneously integrated optical parametric amplification chip

Abstract

The application discloses a monolithic hetero-integrated optical parametric amplification chip, which comprises a substrate, a lower cladding layer, a lithium niobate thin film flat optical waveguide, an optical parametric amplification transmission light path layer, an upper cladding layer and a pump laser epitaxial layer, wherein the optical parametric amplification transmission light path layer comprises a pump light coupling optical waveguide, a pump light transmission optical waveguide, a signal light input mode spot converter, a signal light transmission optical waveguide, a pump light signal light coupler, a periodical polarization lithium niobate thin film optical waveguide, a signal light demultiplexer and a signal light output mode spot converter. The application can realize amplification of input signal light on a single chip, and has the advantages of high integration, low noise, high gain and low insertion loss.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of integrated optical chips, in particular to a monolithic heterogeneous integrated optical parametric amplification chip. BACKGROUND

[0002] The optical amplifier is a key device for realizing the relay amplification of the optical signal in the optical path, and plays an important role in the optical communication and optical network system. The existing optical amplifiers mainly include fiber amplifiers, semiconductor optical amplifiers and optical parametric amplifiers, etc. Among them, the fiber amplifier has the characteristics of large gain and high saturated optical power, and is widely used in the optical network system at present, but it is large in size and high in power consumption, and cannot be applied in the field of photonic integrated chips. The semiconductor optical amplifier has the advantage of integrability, but it has large noise, small gain and low saturated optical power, and cannot be applied in the fields of microwave photon integrated chips, high-speed optical communication chips, quantum computing chips and other high-performance application fields.

[0003] The optical parametric amplifier utilizes the nonlinear effect of the optical nonlinear crystal material, and combines the quasi-phase matching technology to realize the amplification of the optical signal, and has the outstanding advantage of ultra-low noise. At present, the optical parametric amplifier is mainly prepared based on the periodical polarization lithium niobate crystal. The second-order nonlinear effect of the lithium niobate crystal is utilized to realize the parametric conversion, and the periodical polarization technology is utilized to polarize the lithium niobate crystal to obtain the periodical ferroelectric domain inversion to realize the quasi-phase matching structure, and then the optical amplification is realized.

[0004] However, the above optical parametric amplifier is prepared based on the block lithium niobate crystal, adopts the high-power pump laser and the spatial optical path coupling transmission, and is large in size and difficult to integrate. In recent years, the development of the lithium niobate thin film material promotes the miniaturization and integration of the periodical polarization lithium niobate-based optical parametric amplifier, but only the periodical polarization lithium niobate thin film optical waveguide can be prepared on the chip, and the coupling of the pump light and the signal light and the selected output of the signal light still need to be realized by the spatial light or the optical fiber optical path coupling mode outside the chip, which seriously restricts the integrated application of the optical parametric amplifier SUMMARY

[0005] In view of the above problems, the present application provides a monolithic heterogeneous integrated optical parametric amplification chip.

[0006] In order to achieve the purpose of the present application, a monolithic heterogeneous integrated optical parametric amplification chip is provided, which comprises:

[0007] a substrate, a lower cladding layer, a lithium niobate thin film flat optical waveguide, an optical parametric amplification transmission optical path layer, an upper cladding layer, a laser bonding layer and a pump laser epitaxial layer.

[0008] The optical parametric amplification transmission light path layer comprises: a signal light input mode spot converter, a signal light transmission optical waveguide, a pump light coupling optical waveguide, a pump light transmission optical waveguide, a pump light signal light coupler, a periodically poled lithium niobate thin film optical waveguide, a signal light demultiplexer, and a signal light output mode spot converter.

[0009] The substrate, the lower cladding layer, the lithium niobate thin film flat optical waveguide, the optical parametric amplification transmission light path layer, and the upper cladding layer are sequentially attached from bottom to top; the laser bonding layer is attached to the upper surface of the pump light coupling optical waveguide in the optical parametric amplification transmission light path layer, the pump laser epitaxial layer is attached to the upper surface of the laser bonding layer, and the pump laser epitaxial layer and the laser bonding layer both completely cover the upper surface of the pump light coupling optical waveguide; the upper surface of the pump laser epitaxial layer is higher than or flush with the upper surface of the upper cladding layer.

[0010] The signal light input mode spot converter is connected to one end of the signal light transmission optical waveguide; the pump light coupling optical waveguide is connected to one end of the pump light transmission optical waveguide; the other end of the pump light transmission optical waveguide and the other end of the signal light transmission optical waveguide are respectively connected to two input ports of the pump light signal light coupler; one end of the periodically poled lithium niobate thin film optical waveguide is connected to an output port of the pump light signal light coupler, and the other end of the periodically poled lithium niobate thin film optical waveguide is connected to one end of the signal light demultiplexer; the other end of the signal light demultiplexer is connected to the signal light output mode spot converter.

[0011] Further, the substrate is made of silicon or quartz, the lower cladding layer and the upper cladding layer are both made of silicon dioxide, and the thickness of the lower cladding layer and the upper cladding layer is in the range of 1 μm-3 μm.

[0012] Further, the thickness of the lithium niobate thin film flat optical waveguide is in the range of 50 nm-500 nm, the width of the pump light transmission optical waveguide is in the range of 500 nm-3000 nm, and the width of the signal light transmission optical waveguide is in the range of 600 nm-2000 nm.

[0013] Further, the pump laser epitaxial layer is made of an InP-based laser active epitaxial layer or a GaAs-based laser active epitaxial layer, and the light emitting wavelength range is 775 nm-1550 nm.

[0014] Further, the cross section of the ridge back protruding part of the periodically poled lithium niobate thin film optical waveguide is trapezoidal, the lower base of the trapezoid is longer than the upper base, the height of the trapezoid is in the range of 100 nm-500 nm, the length of the lower base of the trapezoid is in the range of 600 nm-2000 nm, and the range of the two base angles on the lower base of the trapezoid is 55°-89°.

[0015] Further, the pump light signal light coupler adopts a Y-branch type coupler; the Y-branch type coupler comprises an upper branch input waveguide, a lower branch input waveguide and a Y-branch coupler output waveguide; at least one pump light multimode interference coupler is prepared on the upper branch input waveguide.

[0016] Further, the pump light signal light coupler adopts a micro-ring type light coupler; the micro-ring type light coupler comprises an upper arm input waveguide, a lower arm input waveguide, a lower arm output waveguide and a ring waveguide; at least one pump light multimode interference coupler is prepared on the upper arm input waveguide.

[0017] Further, the width of the pump light multimode interference coupler ranges from 3 μm to 50 μm.

[0018] Further, the signal light demultiplexer adopts a cascaded directional coupler; the cascaded directional coupler is composed of a cascaded idle light directional coupler and a signal light directional coupler; the cascaded directional coupler further comprises a signal light output waveguide, a pump light output waveguide and an idle light output waveguide.

[0019] Further, the signal light demultiplexer adopts a cascaded multimode interference coupler; the cascaded multimode interference coupler comprises at least two cascaded signal light multimode interference couplers; the width of the signal light multimode interference coupler ranges from 5 μm to 100 μm.

[0020] Compared with the prior art, the present application has the following beneficial technical effects:

[0021] The single-heterogeneous integrated optical parametric amplification chip provided in the present application can realize the generation of pump laser, pump light coupling, optical parametric amplification process and selective output of amplified light on a single chip, thereby solving the problem that the existing optical parametric amplifier cannot be fully integrated on a chip; the single-heterogeneous integrated optical parametric amplification chip provided in the present application introduces a pump light multimode interference coupler in the pump light signal light coupler to filter the spontaneous emission noise of pump light, and has the advantage of ultra-low noise. The single-heterogeneous integrated optical parametric amplification chip provided in the present application is realized by using a subwavelength lithium niobate thin film ridge type optical waveguide, and has the advantages of high integration, high parametric conversion efficiency and large gain. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Fig. 1 is a schematic diagram of the top internal structure of a single-heterogeneous integrated optical parametric amplification chip according to an embodiment of the present application;

[0023] Figure 2 Fig. 2 is a schematic diagram of the cross-sectional structure at A-A' in Fig. 1; Figure 1

[0024] Figure 3 Fig. 3 is a schematic diagram of the cross-sectional structure at B-B' in Fig. 1;​Figure 1 Schematic diagram of the cross-sectional structure at point B-B';

[0025] Figure 4 This is a schematic diagram of a pump optical signal optical coupler structure according to an embodiment of a Y-branch coupler structure;

[0026] Figure 5 This is a schematic diagram of a pump optical signal optical coupler structure according to an embodiment of a micro-ring optical coupler structure;

[0027] Figure 6 This is a schematic diagram of a signal optical demultiplexer structure based on a cascaded directional coupler structure, as shown in one embodiment.

[0028] Figure 7 This is a schematic diagram of a signal optical demultiplexer structure based on a cascaded multimode interference coupler structure;

[0029] Figure 8 This is a schematic diagram of the structure of Example 1;

[0030] Figure 9 This is a schematic diagram of the structure of Example 2;

[0031] Figure 10 This is a schematic diagram of the structure of Example 3;

[0032] Figure 11 This is a schematic diagram of the structure of Example 4.

[0033] Figure reference numerals: 1 Substrate, 2 Lower cladding, 3 Lithium niobate thin-film planar optical waveguide, 4 Optical parametric amplification and transmission optical path layer, 5 Upper cladding, 61 Laser bonding layer, 6 Pump laser epitaxial layer, 41 Signal light input mode converter, 42 Signal light transmission waveguide, 43 Pump light coupling waveguide, 44 Pump light transmission waveguide, 45 Pump light signal coupler, 46 Periodically polarized lithium niobate thin-film optical waveguide, 47 Signal light demultiplexer, 48 Signal light output mode converter, 45-1Y branched coupler, 451 Upper branch input waveguide, 45 2. Lower branch input waveguide, 453Y branch coupler output waveguide, 45-2 micro-ring optical coupler, 454 upper arm input waveguide, 455 lower arm input waveguide, 456 lower arm output waveguide, 457 ring waveguide, 458 pump light multimode interference coupler, 47-1 cascaded directional coupler, 471 idler light directional coupler, 472 signal light directional coupler, 473 signal light output waveguide, 474 pump light output waveguide, 475 idler light output waveguide, 47-2 cascaded multimode interference coupler, 476 signal light multimode interference coupler. Detailed Implementation

[0034] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0035] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive or alternative embodiments. It is expressly understood that the embodiments described herein are combinable with each other.

[0036] Reference Figure 1 As shown in the figure, the present application proposes a monolithic heterogeneous integrated optical parametric amplification chip, comprising: a substrate 1, a lower cladding layer 2, a lithium niobate thin film flat optical waveguide 3, an optical parametric amplification transmission optical path layer 4, an upper cladding layer 5, a laser bonding layer 61, and a pump laser epitaxial layer 6. Each layer here is grown or bonded by a medium. The optical parametric amplification transmission optical path layer 4 is a pattern made on the lithium niobate thin film flat optical waveguide 3.

[0037] The optical parametric amplification transmission optical path layer 4 comprises: a signal light input mode spot converter 41, a signal light transmission optical waveguide 42, a pump light coupling optical waveguide 43, a pump light transmission optical waveguide 44, a pump light signal light coupler 45, a periodically poled lithium niobate thin film optical waveguide 46, a signal light demultiplexer 47, and a signal light output mode spot converter 48. The optical parametric amplification transmission optical path layer 4 is a pattern layer made by photolithography and etching on the upper half of the lithium niobate layer. The basic structures of these components are all optical waveguides. These optical waveguides are connected together to form a complete optical parametric amplification transmission optical path layer 4.

[0038] The substrate 1, the lower cladding layer 2, the lithium niobate thin film flat optical waveguide 3, the optical parametric amplification transmission optical path layer 4, and the upper cladding layer 5 are sequentially adhered from bottom to top. The laser bonding layer 61 is adhered to the upper surface of the pump light coupling optical waveguide 43 in the optical parametric amplification transmission optical path layer 4. The pump laser epitaxial layer 6 is adhered to the upper surface of the laser bonding layer 61. The pump laser epitaxial layer 6 and the laser bonding layer 61 both completely cover the upper surface of the pump light coupling optical waveguide 43. The upper surface of the pump laser epitaxial layer 6 is higher than or flush with the upper surface of the upper cladding layer 5. As shown in the figure, the signal light transmission optical waveguide 42 and the pump light coupling optical waveguide 43 are both trapezoidal in cross-section. Figure 2

[0039] ​The volume of the signal light transmission optical waveguide 42 and the pump light coupling optical waveguide 43 are both strip-shaped; the upper cladding layer 5 is seamlessly grown on all the structures below; the pump laser epitaxial layer 6 is etched after the upper cladding layer 5 is grown, the area where the pump laser epitaxial layer 6 is to be placed is etched to form a hole, and then the pump laser epitaxial layer 6 is attached to the etched hole; the size of the hole can be the same as the pump laser epitaxial layer 6 or larger than the pump laser epitaxial layer 6 by 0.5-2 um, and is generally not more than 2 um; the shape of the pump laser epitaxial layer 6 is a cuboid, and the shape of the hole is also a cuboid; from the perspective of top view, the four edges around the hole are expanded outward by 0.5-2 um than the pump laser epitaxial layer 6, as long as the pump laser epitaxial layer 6 can be attached, and the specific size depends on the integration process precision; in the case of low integration alignment precision, the hole is expanded, and in the case of high precision, the hole can be smaller; the upper surface of the pump laser epitaxial layer 6 can be higher than the upper cladding layer 5 or the same height as the upper cladding layer 5, which depends on the thickness of the pump laser epitaxial layer 6; the thickness of the upper cladding layer 5 is generally 1-3 um, and the thickness of the pump laser epitaxial layer 6 is generally 2-5 um. The upper part of the pump laser epitaxial layer 6 is air.

[0040] The signal light input mode converter 41 is connected to one end of the signal light transmission optical waveguide 42; the pump light coupling optical waveguide 43 is connected to one end of the pump light transmission optical waveguide 44; the other end of the pump light transmission optical waveguide 44 and the other end of the signal light transmission optical waveguide 42 are respectively connected to two input ports of the pump light signal light coupler 45; one end of the periodically poled lithium niobate thin film optical waveguide 46 is connected to the output port of the pump light signal light coupler 45, and the other end of the periodically poled lithium niobate thin film optical waveguide 46 is connected to one end of the signal light demultiplexer 47; the other end of the signal light demultiplexer 47 is connected to the signal light output mode converter 48.

[0041] In one embodiment, the substrate 1 is made of silicon or quartz, the lower cladding layer 1 and the upper cladding layer 5 are both silicon dioxide, and the thickness of the lower cladding layer 1 and the upper cladding layer 5 is in the range of 1-3 um.

[0042] In one embodiment, the thickness of the lithium niobate thin film flat plate optical waveguide 3 is in the range of 50-500 nm, the width of the pump light transmission optical waveguide 44 is in the range of 500-3000 nm, and the width of the signal light transmission optical waveguide 42 is in the range of 600-2000 nm.

[0043] In one embodiment, the pump laser epitaxial layer 6 is made of InP-based laser active epitaxial layer or GaAs-based laser active epitaxial layer, and the light emitting wavelength is in the range of 775-1550 nm.

[0044] In one embodiment, asFigure 3 As shown in the drawings, the cross section of the ridge of the periodically poled lithium niobate thin film optical waveguide 46 is trapezoidal, the lower base of the trapezoid is longer than the upper base, the height of the trapezoid ranges from 100 nm to 500 nm, the length of the lower base of the trapezoid ranges from 600 nm to 2000 nm, and the two base angles on the lower base of the trapezoid each range from 55° to 89°.

[0045] In one embodiment, as shown in the drawings, the pump light signal light coupler 45 adopts a Y-branch type coupler 45-1; the Y-branch type coupler 45-1 includes an upper branch input waveguide 451, a lower branch input waveguide 452, and a Y-branch coupler output waveguide 453; and at least one pump light multimode interference coupler 458 is prepared on the upper branch input waveguide 451. Figure 4

[0046] In one embodiment, as shown in the drawings, the pump light signal light coupler 45 adopts a micro-ring type light coupler 45-2; Figure 5

[0047] The micro-ring type light coupler 45-2 includes an upper arm input waveguide 454, a lower arm input waveguide 455, a lower arm output waveguide 456, and a ring waveguide 457;

[0048] At least one pump light multimode interference coupler 458 is prepared on the upper arm input waveguide 454.

[0049] In one embodiment, the width of the pump light multimode interference coupler 458 ranges from 3 μm to 50 μm.

[0050] In one embodiment, as shown in the drawings, the signal light demultiplexer 47 adopts a cascaded directional coupler 47-1; Figure 6

[0051] The cascaded directional coupler 47-1 is composed of a cascaded idle light directional coupler 471 and a signal light directional coupler 472;

[0052] The cascaded directional coupler 47-1 further includes a signal light output waveguide 473, a pump light output waveguide 474, and an idle light output waveguide 475.

[0053] In one embodiment, as shown in the drawings, the signal light demultiplexer 47 adopts a cascaded multimode interference coupler 47-2; Figure 7

[0054] The cascaded multimode interference coupler 47-2 includes at least two cascaded signal light multimode interference couplers 476;

[0055] ​​​​The width of the signal light multimode interference coupler 476 ranges from 5 μm to 100 μm.

[0056] The following will be described in detail with four typical embodiments as examples.

[0057] Embodiment 1

[0058] In embodiment 1, as shown in Figure 8 The pump light signal light coupler 45 is selected as a Y-branch type coupler 45-1 with two input ports, at least one pump light multimode interference coupler 458 is prepared on the upper branch input waveguide 451 of the Y-branch type coupler 45-1, and the width of the pump light multimode interference coupler 458 is 5 μm.

[0059] The signal light demultiplexer 47 is selected as a cascaded directional coupler 47-1, which is composed of a stray light directional coupler 471 and a signal light directional coupler 472, and the signal light output waveguide 473 of the cascaded directional coupler 47-1 is connected to the signal light output spot converter 48.

[0060] Specifically, the cross section of the ridge back protruding part of the periodically poled lithium niobate thin film optical waveguide 46 is trapezoidal, the trapezoidal height is 300 nm, the trapezoidal lower base width is 1000 nm, and the side wall angle is 70°.

[0061] Specifically, the substrate 1 is silicon, the lower cladding layer 2 and the upper cladding layer 5 are both silicon dioxide, and the thickness of the lower cladding layer 2 and the upper cladding layer 5 is both 2 μm.

[0062] Specifically, the thickness of the lithium niobate thin film flat plate optical waveguide 3 is 300 nm.

[0063] Specifically, the width of the pump light transmission optical waveguide 44 is 800 nm, and the width of the signal light transmission optical waveguide 42 is 1000 nm.

[0064] Specifically, the pump light laser epitaxial layer 61 is an InP-based laser active epitaxial layer, and the light emitting wavelength is 980 nm.

[0065] Embodiment 2

[0066] In embodiment 2, as shown in Figure 9 The pump light signal light coupler 45 is selected as a micro-ring type optical coupler 45-2, which is composed of an upper arm input waveguide 454, a ring waveguide 457, a lower arm input waveguide 455, and a lower arm output waveguide 456, at least one pump light multimode interference coupler 458 is prepared on the upper arm input waveguide 454, and the width of the pump light multimode interference coupler 45 is 10 μm.

[0067] The signal light demultiplexer 47 is a cascaded directional coupler 47-1, which is composed of a signal light directional coupler 472 and a pump light directional coupler 471 in cascade, and the signal light output waveguide 473 of the cascaded directional coupler 47-1 is connected with the signal light output spot converter 48.

[0068] Specifically, the cross section of the ridge of the periodically poled lithium niobate thin film optical waveguide 46 is trapezoidal, the height of the trapezoid is 350 nm, the base width of the trapezoid is 1200 nm, and the sidewall angle is 75°.

[0069] Specifically, the substrate 1 is silicon, the lower cladding layer 2 and the upper cladding layer 5 are both silicon dioxide, the thickness of the lower cladding layer 2 is 2 μm, and the thickness of the upper cladding layer 5 is 3 μm.

[0070] Specifically, the thickness of the lithium niobate thin film planar optical waveguide 3 is 250 nm.

[0071] Specifically, the width of the pump light transmission optical waveguide 44 is 900 nm, and the width of the signal light transmission optical waveguide 42 is 1200 nm.

[0072] Specifically, the pump light laser epitaxial layer 6 is a GaAs-based laser active epitaxial layer, and the light emitting wavelength is 780 nm.

[0073] Embodiment 3:

[0074] In embodiment 3, as shown in Figure 10 The pump light signal light coupler 45 is a Y-branch type coupler 45-1 with two input ports, at least one pump light multimode interference coupler 458 is prepared on the upper branch input waveguide 451 of the Y-branch type coupler 45-1, and the width of the pump light multimode interference coupler 458 is 20 μm.

[0075] The signal light demultiplexer 47 is a cascaded multimode interference coupler 47-2, which includes at least two cascaded signal light multimode interference couplers 476, and the width of the signal light multimode interference coupler is 6 μm.

[0076] Specifically, the cross section of the ridge of the periodically poled lithium niobate thin film optical waveguide 46 is trapezoidal, the height of the trapezoid is 250 nm, the base width of the trapezoid is 1500 nm, and the sidewall angle is 70°.

[0077] Specifically, the substrate 1 is silicon, the lower cladding layer 2 and the upper cladding layer 5 are both silicon dioxide, and the thickness of the lower cladding layer and the upper cladding layer is both 3 μm.

[0078] Specifically, the thickness of the lithium niobate thin film planar optical waveguide 3 is 350 nm.

[0079] Specifically, the width of the pump light transmission optical waveguide 44 is 1000 nm, and the width of the signal light transmission optical waveguide 42 is 1500 nm.

[0080] Specifically, the pump light laser epitaxial layer 6 is a GaAs-based laser active epitaxial layer, and the light-emitting wavelength is 775 nm.

[0081] Embodiment 4:

[0082] In embodiment 4, as shown in Figure 11 The pump light signal light coupler 45 is a micro-ring type optical coupler 45-2, which is composed of an upper arm input waveguide 454, a ring waveguide 457, a lower arm input waveguide 455 and a lower arm output waveguide 456. At least one pump light multimode interference coupler 458 is prepared on the upper arm input waveguide 454, and the width of the pump light multimode interference coupler is 50 μm.

[0083] The signal light demultiplexer 47 is a cascaded multimode interference coupler 47-2, which includes at least two cascaded signal light multimode interference couplers 476, and the width of the signal light multimode interference coupler is 100 μm.

[0084] Specifically, the cross section of the ridge back protruding part of the periodically poled lithium niobate thin film optical waveguide 46 is trapezoidal, the trapezoidal height is 200 nm, the trapezoidal base width is 2000 nm, and the side wall angle is 80°.

[0085] Specifically, the substrate 1 is silicon, the lower cladding layer 2 and the upper cladding layer 5 are both silicon dioxide, the thickness of the lower cladding layer 2 is 3 μm, and the thickness of the upper cladding layer 5 is 2 μm.

[0086] Specifically, the thickness of the lithium niobate thin film flat plate optical waveguide 3 is 400 nm.

[0087] Specifically, the width of the pump light transmission optical waveguide 44 is 3000 nm, and the width of the signal light transmission optical waveguide 42 is 2000 nm.

[0088] Specifically, the pump light laser epitaxial layer 6 is an InP-based laser active epitaxial layer, and the light-emitting wavelength is 1550 nm.

[0089] The scheme is based on the periodically poled lithium niobate thin film optical waveguide to construct a monolithic integrated optical parametric amplification chip, which takes advantage of the strong light field interaction of the lithium niobate thin film optical waveguide under subwavelength scale, and integrates the functions of pump light generation, pump light signal light coupling, signal light amplification and signal light selection output using lithium niobate thin film optical waveguide devices, which has the advantages of high gain, low noise and high integration.

[0090] Specifically, the scheme utilizes a cascade multimode interference coupler structure to construct a pump light and signal light filter, filters the spontaneous emission noise of the pump light at the input end, suppresses the propagation of the noise of the pump light into the periodically poled lithium niobate thin film optical waveguide, filters the signal light at the output end, suppresses the output of the wide spectrum stray light, thereby improving the output signal-to-noise ratio and reducing the noise of the optical parametric amplifier.

[0091] In addition, the scheme also adopts a micro-ring structure to construct a pump light and signal light coupler, through which the pump light in the upper arm input waveguide can be efficiently coupled from the ring waveguide to the lower arm output waveguide, while the signal light cannot be coupled into the ring waveguide, but directly and losslessly propagates to the lower arm output waveguide through the lower arm input waveguide, thereby realizing efficient coupling of the pump light and the signal light.

[0092] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present disclosure.

[0093] It should be noted that the terms "first", "second", "third" in the embodiments of the present application are only to distinguish similar objects, and do not represent a specific order of the objects. Understandably, "first", "second", "third" can be interchanged in a specific order or sequence as allowed. It should be understood that the objects distinguished by "first", "second", "third" can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0094] The terms "include" and "have" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusion. For example, a process, method, device, product or equipment including a series of steps or modules is not limited to the listed steps or modules, but can optionally include other steps or modules not listed or can optionally include other steps or modules inherent to the process, method, product or equipment.

[0095] The above-described embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A monolithic heterogeneously integrated optical parametric amplification chip, characterized by, The application relates to a lithium niobate thin film planar optical waveguide and a preparation method thereof. The optical parametric amplification transmission light path layer (4) comprises a signal light input mode spot converter (41), a signal light transmission optical waveguide (42), a pump light coupling optical waveguide (43), a pump light transmission optical waveguide (44), a pump light signal light coupler (45), a periodical polarization lithium niobate thin film optical waveguide (46), a signal light demultiplexer (47) and a signal light output mode spot converter (48). The substrate (1), the lower cladding layer (2), the lithium niobate thin film planar optical waveguide (3), the optical parametric amplification transmission light path layer (4) and the upper cladding layer (5) are sequentially adhered from bottom to top; the laser bonding layer (61) is adhered to the upper surface of the pump light coupling optical waveguide (43) in the optical parametric amplification transmission light path layer (4), the pump laser epitaxial layer (6) is adhered to the upper surface of the laser bonding layer (61), and the pump laser epitaxial layer (6) and the laser bonding layer (61) both completely cover the upper surface of the pump light coupling optical waveguide (43); the upper surface of the pump laser epitaxial layer (6) is higher than or flush with the upper surface of the upper cladding layer (5). The signal light input mode spot converter (41) is connected with one end of the signal light transmission optical waveguide (42); the pump light coupling optical waveguide (43) is connected with one end of the pump light transmission optical waveguide (44); the other end of the pump light transmission optical waveguide (44) and the other end of the signal light transmission optical waveguide (42) are respectively connected with two input ports of the pump light signal light coupler (45); one end of the periodical polarization lithium niobate thin film optical waveguide (46) is connected with an output port of the pump light signal light coupler (45), and the other end of the periodical polarization lithium niobate thin film optical waveguide (46) is connected with one end of the signal light demultiplexer (47); the other end of the signal light demultiplexer (47) is connected with the signal light output mode spot converter (48). The substrate (1) is made of silicon or quartz, the lower cladding layer (1) and the upper cladding layer (5) are both made of silicon dioxide, and the thickness of the lower cladding layer (1) and the upper cladding layer (5) is 1-3 microns.

2. The monolithic heterogeneously integrated optical parametric amplification chip of claim 1, wherein, The thickness of the lithium niobate thin film planar optical waveguide (3) is 50-500 nm, the width of the pump light transmission optical waveguide (44) is 500-3000 nm, and the width of the signal light transmission optical waveguide (42) is 600-2000 nm.

3. The monolithic heterogeneously integrated optical parametric amplification chip of claim 1, wherein, The pump laser epitaxial layer (6) is made of an InP-based laser active epitaxial layer or a GaAs-based laser active epitaxial layer, and the light emitting wavelength is 775-1550 nm.

4. The monolithic heterogeneously integrated optical parametric amplification chip of claim 1, wherein, ​ 5. The monolithic heterogeneously integrated optical parametric amplification chip of claim 1, wherein, The cross section of the ridge of the periodically poled lithium niobate thin film optical waveguide (46) is trapezoidal, the lower base of the trapezoid is longer than the upper base, the height of the trapezoid ranges from 100nm to 500nm, the length of the lower base of the trapezoid ranges from 600nm to 2000nm, and the two base angles of the lower base of the trapezoid each range from 55° to 89°.

6. The monolithic hetero-integrated optical parametric amplification chip according to claim 1, characterized in that, The pump light signal light coupler (45) adopts a Y-branch coupler (45-1); The Y-branch coupler (45-1) comprises an upper branch input waveguide (451), a lower branch input waveguide (452), and a Y-branch coupler output waveguide (453); At least one pump light multimode interference coupler (458) is prepared on the upper branch input waveguide (451).

7. The monolithic heterogeneously integrated optical parametric amplification chip of claim 1, wherein, The pump light signal light coupler (45) adopts a micro-ring type light coupler (45-2); The micro-ring type light coupler (45-2) comprises an upper arm input waveguide (454), a lower arm input waveguide (455), a lower arm output waveguide (456), and a ring waveguide (457); At least one pump light multimode interference coupler (458) is prepared on the upper arm input waveguide (454).

8. The monolithic hetero-integrated optical parametric amplification chip according to claim 6 or 7, characterized in that, The width of the pump light multimode interference coupler (458) ranges from 3μm to 50μm.

9. The monolithic heterogeneously integrated optical parametric amplification chip of claim 1, wherein, The signal light demultiplexer (47) adopts a cascaded directional coupler (47-1); The cascaded directional coupler (47-1) is composed of a cascaded idle light directional coupler (471) and a signal light directional coupler (472); The cascaded directional coupler (47-1) further comprises a signal light output waveguide (473), a pump light output waveguide (474), and an idle light output waveguide (475).

10. The monolithic heterogeneously integrated optical parametric amplification chip of claim 1, wherein, The signal light demultiplexer (47) adopts a cascaded multimode interference coupler (47-2); The cascaded multimode interference coupler (47-2) comprises at least two cascaded signal light multimode interference couplers (476); The width of the signal light multimode interference coupler (476) ranges from 5μm to 100μm.

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