241102 Optical fiber numerical aperture NA

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Key words: Core NA, fiber numerical aperture NA

For optical communication, part of the optical incident on the optical fiber end face cannot enter the optical fiber, and the optical entering the optical fiber end face may not be transmitted in the optical fiber, only the optical that meets a certain specific condition can be fully reflected in the optical fiber to be transmitted.

As shown in the figure above, a beam of optical, regardless of the range of angles, can only enter the fiber along a specific optical cone Angle (the red part)

For normal transmission, the sine value of this Angle θ is called the fiber numerical aperture NA.

NA：Numerical Apeture

One of the important optical parameters of optical fiber

No dimensions, no units                   NA=n*Sinθ

(n: refractive index of medium; θ : Angle between the optical and the fiber axis, usually called half Angle)

According to the formula, only optical with numerical aperture NA≦nsinθ can be coupled into the optical fiber for transmission. The numerical aperture NA represents the optical fiber's ability to receive optical.

How to correctly select numerical aperture NA?

Physically, the numerical aperture of an optical fiber represents the fiber's ability to receive incoming optical.

The larger the NA, the stronger the ability of the fiber to receive optical, from the point of view of increasing the optical power into the fiber, the larger the NA, the better, because the larger the numerical aperture of the fiber is favorable for the docking of the fiber.

However, when NA is too large, the mode distortion of the fiber increases, which affects the bandwidth of the fiber. Therefore, in the optical fiber communication system, there are certain requirements for the numerical aperture of optical fiber. Generally, in order to most effectively beam optical into the fiber, a lens whose numerical aperture is the same as that of the fiber should be used for optical collection.

General keywords:

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Optical splitter: FBG taper splitter, PLC optical splitter, wave splitter, TAP-PD, multi-mode splitter, multi-mode PLC

Optical switch: mechanical optical switch, MEMS optical switch, magneto-optical switch, optical routing equipment, optical crossover, optical switching, OXC optical matrix, optical switch switching equipment

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High speed cable: DAC, AOC, ACC,AEC,Mini-SAS, HDMI AOC

Integrated cabling: optical jumper, MPO/MTP jumper, armored optical jumper, base station pull high beam jumper, field cable assembly, multi-core cable jumper, ODF fiber distribution frame, fiber connector box, 144 core high density fiber distribution frame, photoelectric composite cable

Optical devices: ring actuator, passive dual fiber to single fiber, passive single multimode conversion, optical isolator, polarization-preserving device, polarization-preserving coupler, polarization-preserving circulator, polarization-preserving jumper, polarization-preserving isolator, PBC/PBS beam binder/splitter, polarization-preserving CWDM, polarization-preserving DWDM

Network security: OTAP rack-mounted splitter, TAP shunt, aggregation shunt, traffic replication, spectral replication, one-way isolation, fiber optic network card

Access equipment: Optical transceiver, protocol converter, optical fiber transceiver, photoelectric converter, PCM equipment, telephone optical transceiver, PDH optical transceiver, video optical transceiver, industrial transceiver, Industrial switch, POE switch, POE transceiver