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Optical coupling options

Our fiber coupled and free-space solutions

Single mode optical fibers

Coupling solution to standard SNSPDs

Single-mode fibers stand out as optimal conduits for transmitting light signals with exceptional precision.

The slender core allows for the propagation of a single, well-defined mode of light, ensuring minimal signal dispersion and count rate optimization. The compact design of SNSPDs aligns seamlessly with the focused beam of a single-mode fiber, enabling efficient coupling.

For certain wavelengths, it is possible to use polarization maintaining fibers (PM Fiber), an extra feature to ensure the maintenance of linearly-polarized light waves launched into the fiber.

We offer single mode fibers with core diameters of 3 um up to 9 um, with the option of PM fibers depending on the wavelength.

Multimode optical fibers

Coupling solution to large-active-area detectors

Perfect for remote laser ranging and astronomy applications, our large-active-area SNSPDs seamlessly couple with 50μm and 28μm fiber core diameters, allowing the transmission of multiple modes through the fiber.

Operating optimally at 850 nm and 1064 nm, multimode fiber-coupled detectors enable the coupling to larger mode areas. Unlike single-mode fibers, light from a multimode fiber introduces varied polarizations, impacting on the system detection efficiency. However, our multimode fiber-coupled SNSPDs provide an invaluable solution for scenarios collecting photons from large mode areas with high count rate between 5 MHz and 10 MHz and up to 50% system detection efficiency. [1,2]


Free-space coupling


Single Quantum provides a free-space coupling solution, SQCam™, comprised of a cryostat with an optical window, which can host an SNSPD array of up to 36 pixels.

This very special architecture allows to have spatial resolution for imaging applications and overcome the limitation of dead time, when higher photon fluxes are deployed. This free space solution is engineered to offer low dark count rate even at telecom and short-wave infrared wavelengths, increasing the signal to noise ratio and dynamic range. 

SQCam™ is suitable for a variety of applications such as bio-imaging and deep-space optical communication.