Integrated on-chip quantum light sources on a van der Waals platform

arXiv:2512.15337 · physics.optics, cond-mat.mtrl-sci, quant-ph · Submitted 2025-12-17 · Read on arXiv

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Introduction to the show: ident: Quantum Radio. Generated commentary on the latest quantum physics and condensed matter papers.

Kai: Today's paper: "Integrated on-chip quantum light sources on a van der Waals platform".

Mira: Integrated on-chip quantum light sources on a van der Waals platform demonstrate an efficient, integrated single-photon source by combining strain-engineered bilayer WSe2 emitters with multimode WS2 waveguides.

Kai: First, who's behind it and why it matters.

Title and authors: Kai: Well, we've got this paper on "Integrated on-chip quantum light sources on a van der Waals platform," and it looks like they've really managed to put a whole quantum light source system onto one chip using these van der Waals materials. Mira, from your perspective as a condensed matter theorist, what makes the title sound so significant?

Mira: I think the significance lies in that integration itself; combining strain-engineered bilayer WSe2 emitters with multimode WS2 waveguides is a very specific architectural choice to create a complete quantum photonic circuit on one substrate. It shows how you can use the distinct properties of different transition metal dichalcogenides to each do one specialized job, which is a key concept in modern integrated photonics research.

Lev: From an error-correction standpoint, I'm curious about the physical realization here; what kind of noise profiles are we looking at when you talk about this single-photon source? We need to know if the coupling efficiency translates into a stable emission rate that can actually sustain a quantum protocol.

Kai: Exactly, Lev, and the authors report some impressive numbers on this paper: under continuous-wave p-shell excitation, they observe an out-coupled single-photon rate at the first lens reaching approximately three hundred twenty kHz, which corresponds to an estimated waveguide-coupled rate of one point seven MHz. It’s a substantial coupling efficiency for a system built entirely from these vdW materials.

Mira: That coupling rate is what really gets my attention; it suggests that the interaction between the WSe2 emitter and the WS2 waveguide modes is quite robust, which means you have a good pathway toward scalable photonic quantum information processing as they aim for.

Lev: A one point seven MHz waveguide-coupled rate sounds promising for establishing a backbone, but we need to know how much of that coupling efficiency is lost during the actual on-chip measurement process versus the theoretical coupling value they're aiming for.

Kai: The paper tackles that head-on by showing results from both an off-chip Hanbury Brown-Twiss configuration and an on-chip one, where they found a purity value of g (two)(zero) equal to zero point zero seven six plus or minus zero point zero two three for the on-chip setup <ref:2512.15337#pg0,both an off-chip Hanbury Brown-Twiss configuration>. That's a direct measurement of the quality of the single photons produced right there in the circuit.

Title and authors: Mira: That purity figure is what allows us to assess if this system can actually deliver high-quality quantum information, and it shows that even within their integrated geometry, they maintain a relatively high degree of single-photon character.

Lev: If we consider running this on real hardware for error correction, the stability of that coupling mechanism under operational conditions is critical; any environmental drift could easily degrade those figures.

Kai: They addressed that by exploring different excitation schemes; they compared above-band excitation with p-shell excitation at a wavelength of eight hundred two nm, and found that the p-shell excitation resulted in brighter emission and a reduced decay time, from fifty-five nanoseconds down to thirty-one point one nanoseconds.

Mira: That reduction in decay time under p-shell excitation suggests a more stable charge environment for the emitter, which is fundamentally important because decoherence is often tied to those environmental fluctuations.

Lev: A shorter decay time definitely helps with timing requirements in quantum protocols; if the emission state lasts less time, we have a better window for subsequent operations before the state degrades.

Kai: Moving into how they build it, they focus on using nanostructured multilayer WS2 as building blocks for their passive components, including multimode slab waveguides that are five hundred nm wide and one hundred fifty nm tall to optimize mode overlap with the emitter <ref:2512.15337#pg2,slab waveguides that are 500 nm wide and 150 nm tall to>.

Mira: The geometry choice of those five hundred by one hundred fifty nanometer slabs is a deliberate design decision intended to maximize the interaction area between the quantum emitter and the photonic circuit, which is a very practical approach for maximizing coupling in this system <ref:2512.15337#pg2>.

Lev: From an engineering standpoint, designing these structures involves significant fabrication challenges; how do you handle maintaining that smooth surface and homogeneous material properties when using mechanical exfoliation of WS2 flakes transferred onto silicon chips?

Kai: They did the fabrication by mechanically exfoliating WS2 flakes and then transferring them onto Si chips with a two micrometer layer of SiO2 and pre-patterned alignment markers, ensuring they have a smooth surface with limited sidewall roughness <ref:2512.15337#pg0>. The photonic circuits are built right on top of those flakes.

Mira: That process highlights the versatility of the van der Waals assembly approach; it shows that even complex passive optical components can be constructed using these 2D materials without introducing excessive material defects into the core circuit function <ref:2512.15337#pg0>.

Title and authors: Lev: If we think about scaling this up for a larger system, like a true chip, I worry about the uniformity of those flakes during transfer; inconsistent flake quality could introduce variable coupling strengths across the entire device.

Kai: They used optical reflectometry to filter the WS2 flakes by their thickness before transferring them onto Si chips, which helps ensure that they have the desired layer thickness needed for good waveguide performance.

Mira: That filtering step is a necessary control mechanism; it shows they are aware that material quality control is as much about the initial selection and preparation of the building blocks as it is about the final circuit design.

Lev: So, back to your point on noise, if we were trying to implement error correction on this, would you say these fabrication methods offer a route toward deterministic placement of qubits or emitters?

Kai: The authors suggest that strain and defect engineering in bilayer WSe2 can be used to place the quantum emitter on demand and even control its polarization, which is crucial for tuning the emission coupling efficiency.

Mira: That level of control over the emitter's physical properties through strain manipulation opens up a lot of possibilities for designing tailored quantum bits, moving beyond just relying on fixed material properties.

Lev: If we could deterministically place and tune those emitters, it would certainly make implementing localized quantum computation much more feasible in a neuromorphic context.

Kai: And that leads into the potential applications; they are envisioning this platform as a way to realize the first demonstration of an integrated single-photon source where both the active emitter and passive circuitry are entirely from vdW materials.

Mira: That monolithic integration is what really sets this apart; it’s not just two separate components working together, but a unified system where all parts share the same material philosophy.

Lev: For real hardware, that monolithic nature reduces interface noise, which is a major hurdle in building scalable quantum systems that rely on many interconnected components.

Kai: And they also explored using NbSe2 nanowires as ultra-thin single-photon detectors because of their superconducting properties, showing the potential for end-to-end integration.

Title and authors: Mira: Integrating the detection material directly onto the same platform as the source is a strong design choice because it minimizes loss and maximizes coherence by keeping everything in close proximity.

Lev: If we look at scaling, that end-to-end integration is powerful, but we still have to worry about integrating many such units without introducing crosstalk between adjacent quantum channels.

Kai: The paper concludes by verifying the single-photon nature using second-order autocorrelation measurements in various Hanbury Brown and Twiss configurations, including using the waveguide itself as an on-chip beam splitter to collect photons from both output ports simultaneously.

Mira: That on-chip HBT measurement is a very clever way to confirm that the output isn't just classical light being channeled, but genuinely quantum correlation from the source.

Lev: Confirming that correlation within the circuit itself is a good step toward validating system performance before you even try to link it to larger error-correction codes.

Kai: So, in summary, this paper on "Integrated on-chip quantum light sources on a van der Waals platform" demonstrates an efficient method for creating an integrated single-photon source by combining strain-engineered bilayer WSe2 emitters with multimode WS2 waveguides.

Mira: The core implication is showing a viable pathway toward scalable photonic quantum information processing by realizing the first demonstration of this kind of integrated system built from van der Waals materials.

Lev: For error correction researchers, it shows a material platform where you can engineer emitter placement and have high-purity emission rates that are already established for the device architecture.

Kai: It opens up possibilities for creating truly monolithic quantum photonic circuits where both the source and the circuit reside in this 2D material system <ref:2512.15337#pg0>.

Mira: The main point remains that combining strain-engineered emitters with WS2 waveguides creates a solid foundation for scalable photonic quantum information processing by realizing this integrated system entirely from van der Waals materials.

Lev: For those working on error correction, it’s exciting because it validates the use of these specific TMDs for creating high-purity sources within a compact, integrated structure.

Kai: This work paves the way for a future where quantum light sources and photonic circuitry are all realized on a single chip using van der Waals materials.

Mira: It really shows how material choice dictates the functionality in this field, providing concrete examples of how to build complex integrated quantum devices.

The paper's summary: Kai: So, to recap, this paper is about taking active quantum emitters and passive photonic circuits, both made from van der Waals materials like WSe2 and WS2, and putting them all together on a single chip to create an integrated source for single photons.

Mira: Exactly; the central argument is that by combining strain-engineered emitters with multimode waveguides, they've managed to build a self-contained quantum light source where the active part and the passive part are both made from these 2D materials <ref:2512.15337#pg0>. It’s about achieving this monolithic integration, which is a big step in making quantum devices more practical for real hardware.

Lev: From my side, I see the implication here as a solid material foundation; if you can reliably create this level of purity and coupling efficiency right on the platform, then it gives us a much better starting point for testing error correction protocols that rely on high-quality photonic states.

Kai: That’s what excites me about it; it moves us past just studying isolated components and shows us a real path toward building functional quantum systems where everything is manufactured in the same material environment.

Mira: I think the real impact is how this platform dictates future design choices; since they are using TMDs for both emission and waveguiding, it sets a precedent that these materials are viable for realizing the entire photonic infrastructure, not just one part of it.

Lev: If we can scale this integration—if we can manage to connect many of these sources and detectors together without introducing significant noise or crosstalk—then we could start thinking about building actual quantum communication links or small quantum processors where the light itself is encoded in these 2D structures <ref:2512.15337#pg0>.

Kai: And that’s a huge leap from what we’ve seen before; it shifts the focus from just proving a concept to showing how to actually manufacture this complex, integrated system using these scalable materials.

Mira: Precisely; the methodology here isn't just about making one good emitter or one good waveguide; it’s about demonstrating that these specific van der Waals materials can handle both functions simultaneously in a way that is efficient and controllable through engineering techniques like strain.

Lev: I’m thinking about the future work, specifically how they plan to integrate detectors like NbSe2 for this source; if we can build a complete loop—source, waveguide, detector—all on one substrate from these materials, that drastically cuts down on the interface losses we usually have to deal with in larger systems.

Kai: That end-to-end integration is what makes it so compelling; it minimizes the points where a photon can get lost or corrupted during its journey from creation to measurement.

Mira: It’s about creating a platform where the quantum information processing happens within the material itself, which could fundamentally alter how we design these types of devices compared to using traditional materials.

Lev: That kind of control over the physical environment suggests that future error correction schemes might be able to leverage the intrinsic properties of these vdW systems to manage noise more effectively than is possible with conventional semiconductor approaches.

The paper's improvements: Tom: So, we're looking at how these authors suggest making this integrated source even better by focusing on material engineering and control, right?

Kai: Exactly; they talk about using strain and defect engineering in WSe2 not just to get a source, but to precisely place the emitter where it needs to be for maximum coupling efficiency.

Mira: I think that’s the core improvement because it moves beyond just having an emitter available; it shows a method for actively tuning its optical properties by manipulating its physical structure within the van der Waals stack.

Lev: If they can deterministically tune the emission properties through strain, that opens up a pathway for creating more tailored quantum bits with specific coupling characteristics, which is crucial for designing robust error correction codes.

Kai: And what about those other materials mentioned? They explore using NbSe2 as an ultra-thin detector because of its superconducting properties, suggesting they can build a complete source-to-detector system all on one platform from these vdW materials.

Mira: That end-to-end material integration is a significant improvement because it minimizes the number of interfaces where photons can interact with the environment or decohere, which should keep the quantum state cleaner over longer periods.

Lev: From an error correction standpoint, having a built-in detector right there on the chip means we could test entanglement and correlation measurements locally with much lower environmental noise than if we had to couple external components.

Kai: It’s about making these systems more self-contained; you don't need delicate fiber coupling or complex external setups to verify the quantum nature of the light coming from this integrated circuit.

Mira: The implication is that this approach could lead to a new generation of scalable quantum devices where the material choice itself is what defines both the source and its detection capabilities, rather than just using separate components for each function.

Lev: That’s fascinating because it means the noise budget for any protocol running on this hardware would be fundamentally different, likely allowing us to run more complex algorithms before error correction overhead becomes too high.

Kai: So, they are pushing toward a system that is not just efficient in generating a photon, but also highly controllable and intrinsically low-noise across its entire operational chain.

Mira: That control over the material's intrinsic quantum properties through engineering provides a level of precision that was previously hard to achieve in such integrated structures.

Lev: If they can achieve this level of deterministic material control, we could start thinking about architectures where the quantum hardware itself possesses some level of inherent robustness against certain types of environmental decoherence.

Conclusion: Kai: So we're wrapping up our discussion on "Integrated on-chip quantum light sources on a van der Waals platform," which essentially showed how to build an entire single-photon source and its necessary circuitry using only 2D van der Waals materials like WSe2 and WS2 <ref:2512.15337#pg0,Integrated on-chip quantum light sources on a van der Waals platform>.

Mira: That’s right; the main point is demonstrating the physical feasibility of monolithic integration, proving that these materials can handle both the active light emission and the passive waveguide functions in one unified system.

Lev: For error correction, this work is really encouraging because it validates a material platform where you can engineer emitter placement and have high-purity emission rates already established for the device architecture.

Kai: It’s a big step because it means we're moving away from building quantum systems with many different materials that all need to be perfectly interfaced.

Mira: Indeed, because this approach suggests that future photonic quantum information processing could rely on a single material family, which simplifies fabrication and potentially reduces interface noise significantly.

Lev: If we can achieve this level of structural control over the emitter placement via strain engineering, it gives us a much more deterministic way to manage the local quantum environment during gate operations.

Kai: So the implication is that we’re looking at a future where these integrated sources could form the backbone of scalable quantum networks, as they show a clear path toward making this technology practical.

Mira: Precisely; it establishes a clear design principle for creating complex photonic circuits using 2D materials, which is something we can use to guide the design of even more intricate quantum architectures <ref:2512.15337#pg0>.

Lev: I just think the next challenge will be taking these demonstrated single-photon sources and integrating them into a larger, functional quantum processor where we can actually run complex error correction algorithms.

Kai: That’s what we'll see in the next phase; moving from a working source to a functioning quantum computer is definitely the next big experimental hurdle.

Mira: It really shows how material science dictates the functionality in this field, providing concrete examples of how to build complex integrated quantum devices using these TMDs.

Lev: For those of us in error correction, this work gives us a solid foundation to start simulating and testing protocols on hardware that actually has the purity levels these authors are reporting.

Kai: So there you have it; this paper on "Integrated on-chip quantum light sources on a van der Waals platform" shows a very promising route forward for building integrated quantum hardware from these 2D materials <ref:2512.15337#pg0,Integrated on-chip quantum light sources on a van der Waals platform>.

Mira: It’s a solid foundation, and the direction they’re pointing toward is very exciting for condensed matter theorists looking at material platforms for quantum applications.

Lev: We look forward to seeing how this platform evolves when we start talking about scaling up the integration of detectors and more complex logic elements on top of these sources.

Department of Electrical and Photonics Engineering, Technical University of Denmark · NanoPhoton – Center for Nanophotonics, Technical University of Denmark

physics.optics, cond-mat.mtrl-sci, quant-ph

Submitted: 2025-12-17

Updated: 2026-10-06

License: http://creativecommons.org/licenses/by/4.0/

Importance score: 80/100

The gist: Integrated on-chip quantum light sources on a van der Waals platform demonstrate an efficient, integrated single-photon source by combining strain-engineered bilayer WSe2 emitters with multimode WS2

Key concepts

van der Waals (vdW) platform: This refers to using materials like WS2 and WSe2 arranged in layered structures. These layers are held together by weak van der Waals forces, allowing them to be stacked precisely. This approach is powerful because it enables the monolithic integration of quantum emitters and light circuits onto a single chip, which is key for scalable quantum devices.
Bilayer WSe2 emitters: These are two layers of tungsten diselenide (WSe2) engineered with strain or defects to act as on-demand single-photon sources. By using bilayer structures instead of single layers, the researchers achieved reduced background light while maintaining high brightness and bright, polarized emission that couples well into the WS2 waveguides.
WS2 waveguides: Tungsten disulfide (WS2) is used as the passive photonic circuit material because it has a high refractive index and low absorption across a broad spectrum above 700 nm. This allows for the creation of low-loss, tightly confined optical modes suitable for building integrated photonics circuits on the chip.

Terminology

Aperture — 5× in this paper · explained in 1 episode
Hanbury Brown-Twiss — 5× in this paper
Trace — 5× in this paper · explained in 2 episodes
Alignment — 4× in this paper · explained in 1 episode
Core — 3× in this paper · explained in 2 episodes
Robustness — 3× in this paper · explained in 5 episodes
Anisotropy — 1× in this paper · explained in 3 episodes
Entanglement — 1× in this paper · explained in 3 episodes
Homogeneity — 1× in this paper · explained in 2 episodes
Structural Control — 1× in this paper · explained in 2 episodes

Summary

Integrated on-chip quantum light sources on a van der Waals platform demonstrate an efficient, integrated single-photon source by combining strain-engineered bilayer WSe2 emitters with multimode WS2 waveguides. This work establishes a pathway toward scalable photonic quantum information processing centered around nanoengineered van der Waals materials by realizing the first demonstration of an integrated single-photon source where both the active quantum emitter and the passive photonic circuitry are realized entirely from vdW materials.

The gist

Bilayer WSe2 quantum emitters are integrated on top of multimode WS2 waveguides, enabling efficient waveguide coupling in a 2D–2D emitter–waveguide system, resulting in an out-coupled single-photon rate at the first lens reaching approximately 320 kHz under continuous-wave p-shell excitation, corresponding to an estimated waveguide-coupled rate of 1.7 MHz.

Platform Versatility and Material Selection

The paper advocates for transition metal dichalcogenides (TMDs) as a powerful material platform due to their strong exciton resonances, large optical oscillator strengths, and versatility afforded by van der Waals (vdW) assembly. The platform is envisioned to integrate quantum emitters, photonic circuitry, and detectors monolithically. Specific components are assigned roles based on their properties:

** Mono- or bilayer WSe2:**

** Serve as on-demand quantum light sources through strain or defect engineering. Bilayers offer reduced background photoluminescence while maintaining high emitter brightness. The emitters exhibit bright, highly polarized emission that couples efficiently into WS2 waveguides. 19–47. 43. 45. 61. **

WS2:

** Acts as the photonic circuit material, possessing high refractive index and low absorption over a broad spectral window above 700 nm that support low-loss, tightly confined optical modes suitable for waveguides and photonic cavities. 26–29. **

NbSe2:

** Explored as ultrathin single-photon detectors due to its superconducting properties. 31–33. **

Waveguide and Grating Coupler Design

The passive optical components are established using nanostructured multilayer WS2 as building blocks for integrated photonics. The proposed waveguide geometry consists of multimode WS2 slab waveguides that are 500 nm wide and 150 nm tall, to enhance the mode overlap with any dipole-like quantum emitter located outside the slab waveguide. 3.

The fabrication involves mechanical exfoliation of WS2 flakes, followed by transfer onto Si chips with pre-patterned alignment markers. The waveguides are characterized by a smooth and homogeneous surface and limited sidewall roughness. 2c, d.

Grating couplers are designed based on a compact silicon nitride design for microscopy systems consisting of concentrical half rings, optimized for microscope operation rather than fiber coupling. Numerical modeling via FDTD simulations determined the main figure of merit as the out-coupling efficiency with a fixed numerical aperture (NA = 0.81) of a propagating mode inside the waveguide. 2g.

Quantum Emitter Coupling and Excitation Schemes

The integration involves transferring a thin layer of hexagonal boron nitride (hBN) on top of the WS2 waveguide, followed by bilayer WSe2. This structure is designed to facilitate the emitter coupling into the waveguide while decreasing the likelihood of bilayer breaking during transfer. 3a.

Coupling efficiency analysis using FDTD simulations showed that leakier modes (either higher-order TE modes or any TM mode) have an overall stronger coupling to the dipole emission due to the larger overlap with the field profile. 2b. The coupling is also dependent on dipole orientation, as both in-plane and out-of-plane dipoles can couple, highlighting the importance of TM or hybrid modes. 3c.

The paper compares two excitation schemes for spectral line at λ = 802 nm: above-band excitation (ABE) and p-shell excitation (PSE). PSE results in brighter emission and simultaneously reduces the spectral background from higher-energy states, leading to stronger photoluminescence than previous examples. The decay time under PSE is reduced from τABE = (55.0 ± 1.1) ns to τPSE = (31.1 ± 0.4) ns, indicating a more stable charge environment under this scheme. 3f, Supplementary Figure 7.

On-chip Second-Order Correlation Measurement

The paper verifies the single-photon nature by performing second-order autocorrelation measurements in different HBT setup configurations. The measurement is repeated by moving the collection spot to one of the grating couplers, where single photons can be collected simultaneously from each output port, and the waveguide itself is used as an "on-chip beam splitter.

Improvements for AI systems

As a fastidious researcher, I have analyzed this paper on integrated quantum light sources based on van der Waals (vdW) materials. While the paper focuses heavily on developing a physical quantum photonic platform, its core contribution lies in demonstrating efficient, integrated single-photon generation and detection at the nanoscale using 2D materials.

The direct application of this specific physical system to improve AI systems is highly indirect and requires a conceptual leap from quantum optics/nanophotonics to machine learning or computation. However, by leveraging the fundamental principles demonstrated in this paper—namely, scalable, high-efficiency single-photon sources and on-chip correlation measurements—we can propose improvements in several advanced AI domains.

Here are the specific improvements I can derive and the capabilities they would enable:

)

Use the demonstrated on-chip HBT (Hanbury Brown and Twiss) measurement capability to develop a novel, ultra-sensitive sensor for detecting subtle changes in quantum states within an AI hardware substrate.
Utilize the high-purity, waveguide-coupled single-photon source to create a scalable quantum communication backbone for secure, low-latency AI model synchronization.
Apply the principles of strain/defect engineering in WSe2 to design novel neuromorphic hardware with on-demand, localized quantum bits (qubits).

Here are the specific improvements and what the improved system can do:

Develop a novel, ultra-sensitive sensor for detecting subtle changes in quantum states within an AI hardware substrate.
Create a scalable quantum communication backbone for secure, low-latency AI model synchronization.
Design neuromorphic hardware with on-demand, localized quantum bits (qubits).

Detailed Specific Improvements and Capabilities:

The paper demonstrates high-purity single-photon emission from strain-engineered bilayer WSe2 emitters coupled to WS2 waveguides, along with the realization of an on-chip Hanbury Brown and Twiss (HBT) measurement configuration.
By integrating this into a sensor architecture, the improved AI system can perform:
Detect minute fluctuations or phase shifts in the quantum state (e.g., charge density, strain field, or magnetic flux) of silicon-based AI processors with near-unity purity and extremely high sensitivity (due to the single-photon nature). This could enable:
Real-time, non-invasive monitoring of device health or operational anomalies in quantum computing components or neuromorphic chips.
Developing a Quantum State Integrity Monitor for AI hardware that detects subtle decoherence events before they manifest as catastrophic computational errors, allowing for preemptive error correction mechanisms within the AI pipeline.
The paper establishes an efficient on-chip coupling mechanism and estimated MHz-level waveguide-coupled count rates (1.7 MHz).
By scaling this architecture to incorporate integrated single-photon detectors (like the NbSe2 SNSPDs mentioned in Section I) and phase modulators, the improved AI system can perform:
Establish a Quantum Interconnect Layer for AI accelerators where data is encoded in quantum states transmitted via on-chip single photons. This would enable:
Secure, low-latency communication between distributed AI nodes (e.g., in a quantum network) or within a large chip where classical crosstalk and latency are prohibitive, significantly reducing the synchronization overhead for massive parallel AI workloads.
The paper details how strain and defect engineering in WSe2 allows for on-demand quantum emitter placement and polarization control, which is key to controlling emission coupling efficiency.
By adapting this material science knowledge to semiconductor fabrication processes (e.g., using deterministic transfer techniques), the improved AI system can design:
Novel Neuromorphic Hardware where the neurons are physical WSe2 quantum emitters, and their connectivity/activity is controlled by applying localized strain fields or external gate voltages that tune emitter coupling efficiency and emission properties. This enables:
The creation of a truly analog, energy-efficient neuromorphic processor where computation is intrinsically linked to the quantum dynamics of the material itself, potentially leading to vastly superior power efficiency compared to traditional digital AI accelerators for specific tasks (e.g., pattern recognition or sparse learning).

Abstract

Scalable photonic quantum information technologies require a platform combining quantum light sources, waveguides, and detectors on a single chip. Here, we introduce a van der Waals platform comprising strain-engineered bilayer WSe 2 quantum emitters, integrated on multimode WS 2 waveguides with grating couplers, enabling efficient on-chip quantum light sources. The emitters exhibit bright, highly polarised emission that couples efficiently into WS 2 waveguides. Under discrete-state excitation, we observe high-purity, waveguide-coupled single-photon emission, measured using both single-port and cross-correlated, multi-port photon streams, yielding g(2)(0) = 0.003+0.030-0.003 and g(2)(0) = 0.076 plus or minus0.023, respectively. For a single output, the out-coupled single-photon count rate at the first lens reaches approximately 357 kHz under continuous-wave discrete-state excitation, corresponding to an estimated minimum waveguide-coupled rate of 1.68 MHz. These results demonstrate an efficient, integrated single-photon source and establish a pathway toward scalable photonic quantum information processing centred around nanoengineered van der Waals materials.