© 2016 by Castor Optics, Inc.

OPERATING WAVELENTGH

The double-clad couplers developed by Castor combine single-mode light transmission with multimode light transfer. Light transmission in the core is quasi-lossless from Port A to Port S, and again from Port S to Port A (see diagrams below). In the inner cladding of the double-clad fiber, light transfer occurs either from the inner cladding of Port S to the multimode branch called Port B in couplers designed for light collection OR from the Port B to the inner cladding of Port S, for couplers designed for injection.

In the multimode regime, our coupler work for all wavelength between 400nm up to 1600nm, with a flat spectral response.

In the single-mode regime, the operating wavelength range for the core of the double-clad fiber is bound by the cutoff wavelength, defined as the smallest wavelength for which we can guarantee single-mode operation. Below that wavelength - indicated below for each coupler - the core of the double-clad fiber still transmit light, but not in the single mode regime. 

Our couplers may be inserted in your fiber optics assembly through the use of connectors or through fusion splicing with other optical fibers. At Castor, we know our couplers inside-out: we also provide custom integration with single mode fibers, double-clad fibers and multimode fibers for applications requiring the highest level of sensitivity. 

DOUBLE-CLAD FIBER COUPLERS

1250-1550nm: Collection DCFC

Castor's flagship product, our double-clad fiber coupler designed for single mode operations at 1300nm and 1550nm. Our double-clad fiber was specifically designed to provide a low cutoff wavelength at 1250nm, perfect for high-resolution optical coherence tomography (OCT) imaging. Combined with a large diameter multimode fiber, this coupler provides the highest multimode transfer of more than 70%. Available via Thorlabs as DC1300LE with and without connectors. Other fiber diameters are available through Castor.

1250-1550nm: Bidirectional DCFC (À modifier)!

Castor is working on a double-clad fiber coupler designed for light injection within a double-clad fiber for applications such as monitoring of laser therapy. Designed for single mode operations at 1300nm and 1550nm, our double-clad fiber was specifically designed to provide a low cutoff wavelength at 1250nm, perfect for high-resolution optical coherence tomography (OCT) imaging. Combined with a large diameter multimode fiber, this coupler provides the highest multimode transfer of more than 70%. Available soon at Thorlabs with and without connectors. 

960-1260nm: Collection DCFC

The little sister of Castor's flagship product, our double-clad fiber coupler designed for operations at 1060nm. Our double-clad fiber was specifically designed to provide a low cutoff wavelength at 960nm, perfect for optical coherence tomography (OCT) imaging. Combined with a large diameter multimode fiber, this coupler provides the highest multimode transfer of more than 70%. Available via Thorlabs as DC1060LE with and without connectors. 

680-980nm: Collection DCFC

Designed for operations at 780nm (with a low cutoff wavelength at 680nm), this 2x2 fiber coupler combines a double-clad fiber (i.e. single mode core surrounded by a multimode inner cladding) with a standard step-index multimode fiber. The double-clad fiber was designed with a small inner cladding, but nonetheless provide guiding through the coupler with virtually no loss (≤0.5 dB). Light in the multimode inner cladding of the DCF is transferred to the output leg of the multimode fiber with ≥70% transmission. The small inner cladding of the fiber behaves like a pinhole in a confocal microscopy setup, preserving optical sectioning while increasing collection efficiency and reducing laser speckle. Additionally, this coupler can be used to combine optical coherence tomography (OCT) with fluorescence imaging, spectroscopy, or confocal microscopy. Available via Thorlabs as DC780SE with and without connectors. 

450-680nm: Collection DCFC

Designed for a cutoff wavelength 450nm, this 2x2 fiber coupler combines a double-clad fiber (i.e. single mode core surrounded by a multimode inner cladding) with a standard step-index multimode fiber. The double-clad fiber was designed with a small inner cladding, but nonetheless provide guiding through the coupler with virtually no loss (≤0.5 dB). Light in the multimode inner cladding of the DCF is transferred to the output leg of the multimode fiber with ≥70% transmission. The small inner cladding of the fiber behaves like a pinhole in a confocal microscopy setup, preserving optical sectioning while increasing collection efficiency and reducing laser speckle. Additionally, this coupler can be used to combine optical coherence tomography (OCT) with fluorescence imaging, spectroscopy, or confocal microscopy. 

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MULTIMODE CIRCULATOR/COMBINER

125um injection with 200um illumination & collection

Castor's Bla bla bla

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MODULES AND DOUBLE-CLAD FIBERS

OCT/fluorescence module

Custom integration of Castor's DCFC (DC1300LE) with wavelength division multiplexers and fiber optics beam splitter in order to combine optical coherence tomography with fluorescence imaging. 

Double-clad fiber

All our couplers come with 1m of double-clad fiber. We also sell more of these custom double-clad fibers. DC1300 is sold through Thorlabs. For other fibers, contact us directly.

Looking for another DCFC? Custom design? Particular module?

Drop Castor a line - we might just be working on what you are looking for, or we'll design it for you.

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