CN101694413A - Optical echo loss calibration transferring part - Google Patents

Abstract

The invention relates to an optical echo loss tester calibration part, in particular to an optical echo loss calibration transferring part, which comprises an FC/APC joint, an optical attenuation device and a full reflector which are sequentially connected via optical fibers. The scheme includes that the optical attenuation device is formed by serially connecting one or pluralities of optical fiber tapering coupling optical attenuators, the full reflector is an optical fiber coupler with a 1*2 standard, and the length difference of two output arms of the optical fiber coupler is 2-3 centimeters. As the optical echo loss calibration transferring part comprises the standard FC/APC joint, the optical fiber tapering coupling optical attenuators and the full reflector made of the optical fiber coupler which are sequentially connected via high-quality optical fibers and the transferring part is an all-fiber structure, the transferring part has low cost, stable and reliable performance, and is better than 0.5 dB in repeatability.

Description

Optical echo loss calibration transferring part

Technical field

The present invention relates to a kind of Optical Return Loss tester calibrating device, particularly relate to a kind of optical echo loss calibration transferring part.

Background technology

Optical Return Loss is called reflection loss again, and it is meant that in the optical fiber junction, back reflected laser is imported the decibels of the ratio of light relatively, and return loss heals greatly better, to reduce the influence of reflected light to light source and system.Along with the development of optical fiber communication, high speed fibre transmission system (as SDH, high-power CATV etc.) must have very high return loss, and Distributed Feedback Laser is because its line width, and output characteristics is easy to be subjected to the influence of return loss, thereby has a strong impact on the performance of system.Even common laser instrument also can be subjected to the influence of return loss to some extent, therefore, the test of the return loss of various optical fibre devices becomes more and more important in the system, and the Optical Return Loss tester is able to widespread use.

The alignment light return loss measuring set is a problem that just proposed in recent years, and developing light return loss transmission part stable and reliable for performance, good reproducibility, that dynamic range is big is the precondition of the value accuracy of alignment light return loss measuring instrument and the linearity.Therefore, when the accuracy of alignment light return loss measuring set and linearity index, need use optical echo loss calibration transferring part stable and reliable for performance, good reproducibility.

Present most measurement technology mechanism is just with a FC/UPC fibre-optical splice (a light return loss value about 55dB can be provided) and the so-called smooth return loss transmission part of a FC/APC fibre-optical splice (a light return loss value about 65dB can be provided) composition, this is unscientific, because the repeatability that part is transmitted in this smooth return loss depends on the quality of fiber end face fully, and these fiber end faces are direct physical contacts when calibrating, and this is several dB with regard to the repeatability that causes this smooth return loss to transmit part.So strictly, it is wrong coming the alignment light return loss measuring set with this smooth return loss transmission part.

A kind of possible technique scheme that can realize light return loss transmission part function is: a variable optical attenuator and a gold-plated full-reflector are coupled together, just can obtain a corresponding Optical Return Loss value by the pad value that changes variable optical attenuator.Its principle is, because light path is reversible, supposes that the insertion loss of variable optical attenuator is 2dB, and the light decay depreciation of setting is 3dB, can obtain the Optical Return Loss of 10dB in theory by such scheme; The light decay depreciation that is provided with is 8dB, can obtain the Optical Return Loss of 20dB in theory, by that analogy.

But this scheme has significant disadvantages, not only plugs light joint and the decline of fiber end face quality at every turn and can make in this way the poor repeatability of the Optical Return Loss value that produces, and generally greater than 1dB, and the realization cost of this scheme is very high.

Summary of the invention

Technical matters to be solved by this invention is that the light return loss that solves the alignment light return loss measuring set is transmitted the part poor repeatability, realized the high problem of cost.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention provides a kind of optical echo loss calibration transferring part, comprises the FC/APC joint, light attenuation device and the full-reflector that are connected successively by optical fiber.

In the such scheme, described light attenuation device draws awl coupling light attenuator to be in series by one or more optical fiber.

Described light attenuation device is that an optical fiber draws awl coupling light attenuator.

Described light attenuation device two or three optical fiber of serving as reasons draw awl coupling light attenuator to be in series.

Described full-reflector is 1 * 2 standard fiber coupling mechanism, and the length of two output arms of this fiber coupler differs 2～3 centimetres.

The present invention includes the full-reflector that the standard FC/APC joint, the optical fiber that are connected successively by high-quality optical fiber draw awl coupling light attenuator and made by fiber coupler, be all optical fibre structure, cost is low, stable and reliable for performance, and repeatability is better than 0.5dB.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the full-reflector structural representation.

Embodiment

Below in conjunction with accompanying drawing the present invention is made detailed explanation.

As shown in Figure 1, the present invention includes FC/APC joint 1, light attenuation device 3 and the full-reflector 4 that connects successively by optical fiber 2.

Adopting the FC/APC joint is because if joint form is FC/PC or FC/UPC, and just can not develop Optical Return Loss is the transmission part of 60dB.The return loss of FC/PC joint is less than 50dB, and the return loss of FC/UPC joint also can only reach about 55dB, it will limit the Optical Return Loss that part is transmitted in the overall optical return loss like this, the return loss of common FC/APC joint is greater than 65dB, the FC/APC joint performance of making standard can be more stable, and repeatability can be better.

Light attenuation device 2 among the present invention draws awl coupling light attenuator to be in series by one or more optical fiber.For Optical Return Loss is the light return loss transmission part of 40dB and (as 10dB, 20dB etc.) below the 40dB, draws awl coupling light attenuator to get final product with single-stage optical fiber.When the damping capacity of this attenuator during less than 20dB, its uncertainty is less than 0.2dB.Under the situation that connects desirable full-reflector, if use the 20dB optical attenuator, the return loss that part can obtain 40dB is transmitted in reflection.This is because light path has forward and reverse both direction, and its light path is reversible for optical fiber draws awl coupling light attenuator, if promptly light positive is to the optical attenuation that 20dB is arranged by this attenuator, also can produce the optical attenuation of 20dB so during oppositely by this attenuator when light.Transmit part for Optical Return Loss greater than the light return loss of 40dB (as 50dB, 60dB etc.), will draw the series connection of awl coupling light attenuator to make with two-stage or multi-stage fiber.For example, be the reflection transmission part of 50dB for return loss, can draw the series connection of awl coupling light attenuator to make with two optical fiber, the damping capacity of one of them is 10dB, another damping capacity is 15dB; For return loss is that part is transmitted in the reflection of 60dB, can be in series with the attenuator that 3 damping capacitys are 10dB, also can make with the attenuator series connection that two damping capacitys are 15dB, and to be the former Duoed a welding point than the latter in their difference.Because modern optical fiber splicer function admirable, the single-mode fiber splice loss, splice attenuation is less than 0.05dB, so this difference can be ignored.

Full-reflector among the present invention adopts fiber coupler to make.Because modern production technology is very ripe, every technical indicator of fiber coupler has obtained improving significantly.Directivity as coupling mechanism can reach more than the 70dB, and spectrum width is greater than 20nm, and the uncertainty of splitting ratio is less than 0.4%, and added losses are less than 0.04dB, and polarization dependent loss is less than 0.04dB or the like.For the full-reflector that makes development can access stable effect, must eliminate the influence of interference effect.As shown in Figure 2, the light of light emitted incides two output arm 42,43 respectively through the input end 41 of 50: 50 fiber couplers, above-mentioned two output arms 42 and 43 tail end welding.If two output arms 42 are the same with 43 length, at this moment satisfy coherent condition, and interference effect is the strongest.Therefore, two output arms 42 and 43 length difference must be greater than 2～3 centimetres, this is because the employed light source of most Optical Return Loss testers is a FP type light source, the spectral width of this light source is greater than 1nm, is that the coherent length of laser in optical fiber of the light emitted of 1nm is for spectral width:

$l_c=\frac{{\mathrm{\λ}}^2}{n\×\mathrm{\Δ\λ}}=\frac{{1.31}^2}{1.46\×0.001}\≈1175.41\mathrm{\μm},$

So that the length difference of two output arms of fiber coupler is suitable greater than 2～3 centimetres.

The implementation of the optical attenuator among the present invention also has optical fiber dislocation welding, optical fiber to twine, insert optical attenuation sheet etc. in light path, and these schemes can realize reducing the luminous power in the optic fibre light path.

The present invention is not limited to above-mentioned preferred forms, and anyone should learn the structural change of making under enlightenment of the present invention, and every have identical or close technical scheme with the present invention, all falls within protection scope of the present invention.

Claims (5)

1. optical echo loss calibration transferring part is characterized in that comprising the FC/APC joint, light attenuation device and the full-reflector that are connected successively by optical fiber.

2. optical echo loss calibration transferring part as claimed in claim 1 is characterized in that described light attenuation device draws awl coupling light attenuator to be in series by one or more optical fiber.

3. optical echo loss calibration transferring part as claimed in claim 2 is characterized in that described light attenuation device is that an optical fiber draws awl coupling light attenuator.

4. optical echo loss calibration transferring part as claimed in claim 2 is characterized in that described light attenuation device two or three optical fiber of serving as reasons draw awl coupling light attenuator to be in series.

5. as claim 1 to 4 a described optical echo loss calibration transferring part of each claim, it is characterized in that described full-reflector is 1 * 2 standard fiber coupling mechanism, and the length of two output arms of this fiber coupler differs 2～3 centimetres.

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