The bright correlated photon source is a fully integrated, fiber-coupled solution for generating high-quality time/energy entangled photon pairs via spontaneous parametric down conversion (SPDC). Designed for demanding quantum optics and quantum information experiments, this source combines a stabilized pump laser, thermally controlled nonlinear waveguide, and optimized optical filtering in a single, compact 3U enclosure. It delivers turn-key operation at room temperature, removing the traditional complexity of free-space alignment, external pump lasers, and bulk filtering optics commonly associated with custom SPDC setups.

At the core of the system is an SPDC medium that is actively temperature stabilized to maintain ideal phase matching conditions. This thermal control ensures high and repeatable photon-pair generation efficiency over extended operating times. After down-conversion, residual pump photons are strongly suppressed using built-in low-noise optical filters, yielding a clean output with a high signal-to-noise ratio. The internal architecture is realized entirely in fiber, providing excellent robustness against mechanical vibrations and environmental fluctuations while preserving optical alignment over the device’s lifetime.

The integrated pump laser offers up to 12 mW of variable output power, controlled through an internal variable optical attenuator. This enables users to conveniently tune the pair-generation rate to match the requirements of different experiments, from low-flux, single-photon regime measurements to higher-count applications where bright sources are essential. Under continuous-wave operation, the broadband configuration typically achieves pair-generation rates on the order of 10×106 pairs per second, while the narrowband configuration provides about 2×106 pairs per second, both measured in the low-power regime. These performance levels place the source among the brighter commercial SPDC systems used in research laboratories and pilot quantum technology testbeds.

Two standard spectral configurations are available to address different use cases. The broadband model is optimized around a degeneracy wavelength of 1550 nm, covering an approximate full width at half maximum (FWHM) bandwidth of 80 nm across the C and L telecommunication bands. In this configuration, signal and idler photons are separated using a wavelength-division multiplexer (WDM), providing two output ports suitable for fiber-based quantum communication, quantum networking, and telecom-compatible quantum key distribution. This wide spectral coverage is particularly attractive for wavelength-multiplexed experiments and for interfacing with standard telecom components such as DWDM filters, low-loss single-mode fibers, and InGaAs-based single-photon detectors.

For applications that require tighter spectral control or compatibility with silicon and free-space detectors, a narrowband configuration is offered. In this version, photon pairs are generated at two main wavelengths near 1550 nm and 810 nm, each within a few nanometers of bandwidth. A polarizing beam splitter (PBS) is used to separate the photons into two output ports, resulting in a polarization-correlated (or polarization-entangled, depending on the setup) pair source that is well suited for quantum metrology, fundamental tests of quantum mechanics, and hybrid quantum systems that link near-infrared and telecom platforms. The dual-wavelength architecture allows one photon to be efficiently detected with high-performance silicon avalanche photodiodes at 810 nm, while its partner is compatible with long-distance low-loss transmission at 1550 nm.

The system achieves typical noise suppression levels around 75 dB for the pump light, which significantly reduces accidental counts and enhances heralding efficiency. This high level of pump rejection is critical for experiments requiring precise timing correlations, such as heralded single-photon generation, entanglement distribution, and quantum interference measurements. In comparison to many laboratory-built SPDC sources that rely on separate pump lasers and bulk optics, this integrated unit streamlines the experimental setup, shortens configuration time, and improves overall repeatability of results from one session to the next.

With a signal/idler degeneracy wavelength accuracy on the order of 0.5 nm, the source offers reliable spectral positioning, which is important when interfacing with narrowband filters, optical cavities, or pre-existing fiber infrastructure. This level of precision supports experiments that require long-term stability of the photon wavelength, such as quantum memory interfacing, high-visibility Hong–Ou–Mandel interference, and advanced quantum communication protocols. The ability to customize wavelength and bandwidth for volume orders further extends the source’s ap&