Munti-Mode Fiber Patchcord

A fiber-optic patch cord connects two distant fiber optic ends and uses the same type of fiber and connections as the tips of the respective fibers it connects. In the context of optogenetics experiments with the rotary joint, a fiber optic patch cord is needed to connect the light source and the rotary joint and yet another patch cord to connect the rotary joint and the fiber-optic cannula.

Fiber Cladding type: GRIN-INDEX FIBER and STEP INDEX Fiber

Numerical Aperture

Numerical Aperture (NA), a measure of the acceptance angle of a fiber, is a dimensionless quantity.  For applications, it is most commonly expressed as
NA = ni sinθa

where θa is the maximum 1/2 acceptance angle of the fiber, and ni  is the index of refraction of the material outside of the fiber. This material is typically air, making it equal to approximately 1.0, as shown in the figure.

Structure of a patch cord

The core and the cladding are two layers that make up the lightguide. However, the light travels inside the core of the fiber-optic, barely or not inside the cladding. For this reason, interconnected fiber-optics should have the same core diameter. Different cladding diameters have no influence on the coupling efficiency.
The buffer is a protective layer that tightly encircles the cladding. For fiber patch cords, we usually recommend the use of another protective layer, called jacket, which is a tube covering the previously mentioned layers of the cable.

Fiber Connector

FC-PC

SMA

FC-APC

??

ST

SC

ZF-1.25

ZF-2.5

Cord diameter (+/-2%)

25um

50um

50um

60um

62.5um

105um

NA

0.11

0.126

0.22

0.12

0.22

0.22

Transmission Range

UV

UV

IR

UV

IR

UV

Spectrum Range(nm)

300~1200

250~1200

420~2400

250~1200

420~2400

190~1200

Step Index Multi-Mode Fiber

Cord diameter (+/-2%)

105um

200um

200um

300um

365um

400um

NA

0.22

0.22

0.22

0.22

0.22

0.22

Transmission Range

IR

UV

IR

UV

IR

UV

Spectrum Range(nm)

420~2400

190~1200

420~2400

190~1200

420~2400

190~1200

Step Index Multi-Mode Fiber

Cord diameter (+/-2%)

550um

600um

600um

800um

800um

910um

NA

0.22

0.22

0.39

0.22

0.39

0.22

Transmission Range

IR

UV

IR

UV

IR

IR

Spectrum Range(nm)

420~2400

190~1200

420~2200

190~1200

420~2200

420~2400