FIBER ALIGNMENT AND JOINT LOSSES EBOOK DOWNLOAD

FIBER ALIGNMENT AND JOINT LOSSES EBOOK DOWNLOAD

FIBER ALIGNMENT AND JOINT LOSSES EBOOK DOWNLOAD!

Fiber joints are permanent or removable connections between multimode or Coupling losses depend substantially on the used technology. mechanical splices, which are relatively simple alignment devices holding the fiber ends together. Explanation: Intrinsic loss is defined as the summation of lateral offset loss and angular misalignment loss. In case of multimode fibers, the intrinsic loss is dependent on the refractive index gradient. The intrinsic loss through a single mode fiber joint is independent of direction of propagation. Optical Fiber Communication. 10EC LECTURE UNIT - 4. FIBER COUPLERS AND CONNECTORS. Introduction, fiber alignment and joint loss, single mode.


FIBER ALIGNMENT AND JOINT LOSSES EBOOK DOWNLOAD

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FIBER ALIGNMENT AND JOINT LOSSES EBOOK DOWNLOAD


There are different techniques for joining fiber ends: Permanent and stable connections with very low transition losses can be obtained by fusion splicing.

FIBER ALIGNMENT AND JOINT LOSSES EBOOK DOWNLOAD

Essentially, the fiber ends are fused together with a heat treatment. Semi-permanent connections can fiber alignment and joint losses made with mechanical splices, which are relatively simple alignment devices holding the fiber ends together. Typically, some index matching gel or an epoxy is used for reducing reflection losses.

Compared with fusion splices, mechanical splices are faster to make and can be removed after use. The initial cost is much lower, but the cost per splice is higher. The splice losses and reflection loss are of the order of 0. Fiber connectors are convenient for connections which need to be released more often.

Fiber alignment and joint loss

Common connector types are named FC, SC and LC for single-mode applications and ST for multimode, but there are also dozens of other types, with special qualities such as duplex connections, particularly small size, built-in shutter for improved laser safetyetc. In most cases, the fiber is glued into the connector with some epoxy, and then the fiber end is polished.

The transition losses of connectors are similar to those of mechanical splices, although the stability is generally lower. Microscope imagine of a fusion splice between a photonic crystal fiber PCF, left side and a fiber alignment and joint losses fiber right side.

The hole pattern of the PCF can be seen. Also, certain authors assume index matching and hence no Fresnel reflection, which makes the first term in Eq.

FIBER ALIGNMENT AND JOINT LOSSES EBOOK DOWNLOAD

This may be valid if the two fiber ends are assumed to be in close contact i. Nevertheless, bearing in mind these possible inconsistencies, useful estimates for the attenuation due to lateral misalignment of multimode step index fibers may be obtained.

Lateral misalignment loss in multimode graded index fibers assuming a uniform distribution of optical power throughout all guided fiber alignment and joint losses was calculated by Gloge.

A further estimate including the leaky modes gave a revised expression for the lateral misalignment loss fiber alignment and joint losses in Eq. Factors causing fiber—fiber intrinsic losses were listed in previous Section; the major ones comprising a mismatch in the fiber core diameters, a mismatch in the fiber numerical apertures and differing fiber refractive index profiles are illustrated in Figure 2.

Connections between multimode fibers with certain of these parameters being different can be quite common, particularly when a pigtailed optical source is used, the fiber pigtail of which has different characteristics from the main transmission fiber.

Fiber Joints

Moreover, as indicated previously, diameter variations can occur with the same fiber type. Assuming all the modes are equally excited in a multimode step or graded index fiber, and that the numerical apertures and index profiles are the same, then the loss resulting from a mismatch of core diameters see Figure 2.

It may be observed from Fiber alignment and joint losses. In addition, only a relatively small loss 0. When the transmitting fiber has a higher numerical aperture than the receiving fiber, then some of the emitted light rays will fall outside the acceptance angle of the receiving fiber and they will therefore not be coupled through the joint.

Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS

Lateral misalignment reduces the overlap region between the two fiber cores. The lateral misalignment loss in decibels may be determined using: The predicted losses obtained using the formulas given in Eqs 2.

This assumption fiber alignment and joint losses only correct for certain cases of optical fiber transmission.

Also, certain authors assume index matching and hence no Fresnel reflection, which makes the first term in Eq. This may be valid if the two fiber ends are assumed to be in close contact i.

Nevertheless, bearing in mind these possible inconsistencies, useful estimates for the attenuation due to lateral misalignment of multimode step index fibers may be obtained. Lateral misalignment loss in multimode graded index fibers assuming a uniform distribution of optical power throughout all guided modes was calculated by Gloge.

A further estimate including the leaky modes gave a revised expression for the lateral misalignment fiber alignment and joint losses given in Eq.