MPO/MTP ASSEMBLIES – THE GAME CHANGER OF DATA CENTER CABLING

High-density data center is becoming the direction of the next generation data center. Today density is the key factor that determines the capacity of the facility. Parallel optics technology has become the transmission option of choice in many data centres as it is able to support 10G, 40G, and 100G transmission. For parallel optics to work effectively, it requires the right choice of cable and connector.

An optical fiber connector terminates the end of an optical fiber, and enables quicker connection and disconnection than splicing. The connectors mechanically couple and align the cores of fibers so light can pass. Better connectors lose very little light due to reflection or misalignment of the fibers. In all, about 100 fiber optic connectors have been introduced to the market. MPO/MTP® connector – “multi-fiber push on” technology with multi-fiber connectors offers ideal conditions for setting up high-performance data networks in data centers to handle future requirements.

MTP/MPO cabling assemblies, as an excellent solution for quick and reliable multi-mode fiber connectivity, provide an effective way for 40GbE and 100GbE network solutions, ensuring a high-performance and high-speed network

The MTP® connector is a registered trademark and design of UsConnec. It is also a kind of MPO connector but with a higher performance which provides some advantages over a generic MPO connector. Compared to generic MPO connector, MTP® is designed with multiple engineered product enhancements to improve optical and mechanical performance.

MT stands for mechanical transfer and an MT ferrule is a multi-fibre (usually 12 fibres) ferrule. The performance of the connector is determined by the fibre alignment and how this alignment is maintained after connection. Ultimately, the alignment is determined by the eccentricity and pitch of the fibre and how accurately the guide pins keep the fibres together during mating. The performance of any MPO connector can be improved if the tolerances of the pins and the moulding processes are reduced during manufacture.

Nowadays, a MPO/MTP® connector can support 2, 4, 8, 12 or 24 fibers, and even up to 72 fibers in the tiniest of spaces. MTP/MPO fiber cables fall on MTP/MPO trunk cables and MTP/MPO harness cables. As terminated with MTP/MPO connectors on one end and standard LC/FC/SC/ST/MTRJ connectors (generally MTP to LC) on the other end, these cable assemblies can meet a variety of fiber cabling requirements.

MTP/MPO CASSETTES

MTP/MPO cassettes are utilized to interconnect MTP/MPO backbones with LC/SC/ST/FC patching, and reduce installation time and cost for optical networking environments. They are able to provide secure transition between MTP/MPO and LC/SC/ST/FC connector. The standard MTP/MPO cassettes can accommodate 12 and 24 port configurations.

MTP/MPO CASSETTES FEATURES

High density easy-plug cassette modules

Simple to use, convenient installation: Pre-installed with fiber MTP/MPO adapters at the rear, and LC adapters in the front panel. Reduces cable load in raised floors to existing active server/switch/storage equipment with LC Duplex interface.

Field terminations Elimination: reduces labour cost and improves cabling manageability.

Available in 12 fiber and 24 fiber configurations, up to 36 duplex ports or up to 72 single-mode fibers. For example, a 10G system would utilise a single MPO / MTP (12 Fibre) connector between the 2 switches.

High performance zirconia sleeve adaptors.

Reliability -100% tested factory tested in a controlled environment.

The gender can be changed after assembly or even in the field giving flexibility at point of use.

The MTP connector has a metal pin clamp with features for centering the push spring

eliminates lost pins

centers the spring force

eliminates fibre damage from the spring mechanism

APPLICATIONS

Data centre infrastructure

Storage area network

Fibre channel

Parallel optics

Ultra High Density Fiber Management

Telecommunications networks and Broadband CATV networks.

LAN/WAN Premises

Therefore, parallel optics and MTP cabling have proven to be an excellent solution for delivering 10G, 40G and 100G transmission especially within a data centre environment. It provides a flexible, high density option for quickly connecting services and is a reliable high speed solution for many data networks.

Whether to Use EDFA Amplifier in Long WDM System Or Not?

Currently, utilizing WDM technology to deploy the optical network has received widespread attentions, which enables higher capacity for data transmission. However, the technology is also limited by the transmission distance. When deploying a long WDM system, the signal power would still become weak due to the fiber loss. In order to address the issue, using EDFA amplifier to directly enhance the WDM signals would be a good choice for current and future optical network needs. The optical network combining WDM technology and EDFA module together can transmit multiple signals over the same fiber, at lengths up to a few hundred kilometers or even transoceanic distances. To better know how does EDFA amplifier work in the long WDM system, let’s learn the EDFA amplifier knowledge and analyze the performance of WDM system bonding with the EDFA module.

Introduction to EDFA Amplifier

EDFA amplifier, also referred to as erbium-doped fiber amplifier, is basically composed of a length of Erbium-doped fiber (EDF), a pump laser, and a WDM combiner. When it works, the pump laser with 980 nm or 1480 nm and the input signal around 1550 nm can be combined by the WDM combiner, then transmitted and multiplexed into the Erbium-doped fiber for signal amplification. The pump energy can be transmitted in the same direction as the signal (forward pumping), or the opposite direction to the signal (backward pumping), or both direction together. And the pump laser can also using 980 nm or 1480 nm, or both. Taking the cost, reliability and power consumption into account, the forward pumping configuration with 980nm pump laser EDFA amplifier is always the first choice to enhance the signals for a long WDM system.

Analysis of WDM Network Without EDFA Amplifier

Before analyzing WDM network deployed with EDFA amplifier, it is necessary to know the basic configuration of an original WDM network, as shown in the figure below. We can learn that four signals from different channels are combined by the optical combiner. And then, the integrated signals are transmitted through an optical fiber. Thirdly, the signals are split into two parts by the splitter. One part passes through the optical spectrum analyzer for analyzing signals, and the other one goes through the photo detector to be converted into electrical signal and then be observed by the electrical filter and scope. However, in the process, the signal power gets highly attenuated after being transmitting at long distance.

Analysis of WDM Network Using EDFA Amplifier

By using the EDFA amplifier, we can easily overcome the attenuation of long WDM network. From the following figure, we can learn that EDFA amplifiers act as booster amplifier and pre-amplifier to enhance the signal, so that system will no longer suffer from losses or attenuation. Therefore, if you need to deploy a long WDM system, it is highly recommended to deploy the EDFA amplifiers in the system that features flat gain over a large dynamic gain range, low noise, high saturation output power and stable operation with excellent transient suppression. It is an undoubtedly ideal solution with reliable performance and relatively low cost to extend the WDM network transmission distance.

Conclusion

It is well know that the signal power would be greatly attenuated when the transmission distance is long enough. Hence, when deploying a long WDM network, it is definitely necessary to use the EDFA amplifier to enhance the signal strength, allowing for the long transmission distance. As a preferable option, the EDFA amplifier with very low noise is relatively insensitive to signal polarization and easy to realize signal amplification.

Bridge Copper to Fiber With PoE Media Converter

It’s common to see in modern society that many enterprise networks must support a wide range of installation environments located indoors and out. Considering this, a wide range of media converters and power supply options are important. And with the great benefits of fiber optic cables being accepted widely, PoE media converter seems to be a better choice for enterprise networks. Today this article intends to explain what PoE media converter can bring for managers and its applications.

PoE Media Converter Basis

PoE media converter is a type of fiber-to-copper media converter. It enables enterprises to power their network devices over the existing copper connections. With its PoE injector, PoE media converters can power devices like IP phones, video conferencing equipment, IP cameras and Wi-Fi devices over copper UTP cabling. Besides, they are available in a variety of multi-port configurations, including dual RJ-45 and dual fiber ports, and they can support fixed fiber connectors or SFP (Small Form Pluggable) transceivers.

Once PoE media converters are connected into network systems, they are usually close to the PDs (Power devices) like IP cameras and wireless access points. And when they work, fiber is run to the power source via the SFP socket, and PoE is distributed over UTP cabling to the power devices via RJ45 port.

Network Design Options Provided by PoE Media Converter

PoE media converters bring great benefits for network deployments. For example, they eliminate the need for power supply devices, power cables and outlets that would be required for remote device. In addition, they also provide flexible network design options. Here are some examples.

PoE Media Converter with Single Fiber Ports

As shown in the following picture, single fiber ports are deployed in star topologies with a point-to-point style layout with the fiber switch in the center of the network.

PoE Media Converter with Dual Fiber Ports

Option 1: daisy chain design. This design uses dual fiber ports to support connections in a liner daisy chain configuration. It suits long-haul applications along subways and rail lines.

Option 2: fiber ring design. In this fiber ring architecture, traffic can flow in both directions. In the picture below, a switch connects three PoE media converters to form a ring. If a fiber

failure occurs in it, the switch can reroute the traffic in the opposite direction.

Option 3: redundant fiber design. This network structure uses two fiber connections. One is active and carries the data traffic. The other is a protection fiber port that back-up a fiber failure switch-over of less than 50 milliseconds.

Applications of PoE Media Converter

As we all know, in order to break out the distance and bandwidth limitations of copper cables, fiber optic cable is a good alternative. PoE media converters can convert copper to fiber and provide power at the same time, making it popular among enterprise networks. There are three main applications of PoE media converters.

Fiber to IP cameras. The PoE media converters have fiber uplink ports and downlink ports. And in most applications, two IP cameras at each location can be connected through the dual RJ-45 ports of a PoE media converter.

Fiber to wireless access points. PoE media converters enable wireless access points to be installed in office buildings, airport, hotels, public areas or other places needed.

Fiber to the desktop. The PoE media converters provide fiber to copper media conversion, and they send data and power to desktop items such as IP phones and video conferencing equipment.

Summary

PoE media converters provide a cost-effective way to extend distances over fiber optic cabling to PoE powered devices (PDs). In this article, four network designs with PoE media converters and three applications of them are illustrated simply. If you want to know more details about PoE media converters, please visit fiber-mart.COM.

Comparison of Passive DWDM and Active DWDM System

DWDM (dense wavelength division multiplexing) technology is an ideal solution to address the capacity-hungry issue, which can simply fall into two types, passive DWDM and active DWDM. To greatly expand the bandwidth of the existing fiber system, both passive DWDM and active DWDM systems are designed to multiplex different wavelengths for carrying multiple signals over one single fiber. To better know the features of these two DWDM systems, the following will intend to learn what are the passive DWDM and active DWDM systems, and find their advantages and disadvantages.

Passive DWDM System Overview

Since there is no any active component used in the passive DWDM system, the performance of the passive DWDM link only depends on the optical budget of the DWDM transceivers used in the system. That’s to say, the transmission distance the passive DWDM system supports can’t be extended and is limited to the optical budget of the DWDM transceivers. We can learn from the figure below that shows a common passive DWDM system. Obviously, no active component like fiber amplifier and DCM module, but a pairs of 20 channels DWDM Mux are used. This design allows for high capacity transmission and makes capacity expansion possible. In short, it is very suitable to deploy passive DWDM system in metro networks and high speed and capacity communication lines.

Active DWDM System Overview

Unlike passive DWDM system, active DWDM system can be composed of fiber amplifier, DWDM Mux, DWDM transceiver, DCM module and OEO transponder, which can be also called transponder-based system. Due to its active feature, it is easier to manage and control the optical active DWDM network. Here offers the design of the active DWDM system for your reference.

DWDM (dense wavelength division multiplexing) technology is an ideal solution to address the capacity-hungry issue, which can simply fall into two types, passive DWDM and active DWDM. To greatly expand the bandwidth of the existing fiber system, both passive DWDM and active DWDM systems are designed to multiplex different wavelengths for carrying multiple signals over one single fiber. To better know the features of these two DWDM systems, the following will intend to learn what are the passive DWDM and active DWDM systems, and find their advantages and disadvantages.

Passive DWDM System Overview

Since there is no any active component used in the passive DWDM system, the performance of the passive DWDM link only depends on the optical budget of the DWDM transceivers used in the system. That’s to say, the transmission distance the passive DWDM system supports can’t be extended and is limited to the optical budget of the DWDM transceivers. We can learn from the figure below that shows a common passive DWDM system. Obviously, no active component like fiber amplifier and DCM module, but a pairs of 20 channels DWDM Mux are used. This design allows for high capacity transmission and makes capacity expansion possible. In short, it is very suitable to deploy passive DWDM system in metro networks and high speed and capacity communication lines.

Active DWDM System Overview

Unlike passive DWDM system, active DWDM system can be composed of fiber amplifier, DWDM Mux, DWDM transceiver, DCM module and OEO transponder, which can be also called transponder-based system. Due to its active feature, it is easier to manage and control the optical active DWDM network. Here offers the design of the active DWDM system for your reference.

Active DWDM

In the active DWDM system, the transponder usually utilizes short wave 850nm or long wave 1310nm to do the optical-electrical-optical (OEO) DWDM conversion. When the long distance is required in the active DWDM system, several EDFA fiber amplifiers will be inserted along the active DWDM link. What should be noted is that the active DWDM link can’t be extended infinitely, because the number of fiber amplifiers for an active DWDM link is limited to the optical cable type, the channel count, the data transmission rate of each channel, and permissible OSNR value, etc.

Furthermore, the chromatic dispersion occurring in the optical transmission also makes an influence on the transmission distance of the active DWDM link. Hence, when designing the active DWDM system, we should also take the permissible chromatic dispersion values of the link into consideration. If needed, we can insert the dispersion compensators (dcm modules) into the active DWDM link to enhance the optical signals for a longer transmission.

Passive DWDM vs Active DWDM System

It is well known that the passive DWDM system doesn’t need fiber amplifiers or dispersion compensators, which may saves you a lot of time and money. Meanwhile, it is also very easy to deploy due to the uncomplex installation. However, there are also several disadvantages of passive DWDM system. Firstly, the scalability is not so good as the active one. With the development of the passive DWDM system, more passive devices are required. Meanwhile, the passive DWDM system will be difficult to manage with the increasing of passive devices. What’s worse, if a wavelength or connection needs to be changed in the link, the only option is to take it out of link and disconnect the connection.

As for the active DWDM system, it can multiplex more wavelengths over a single fiber pair. Hence, more bandwidth can be provided by the active DWDM system. Furthermore, the active setups make the optical system management easier. And you can directly change the wavelengths or connections in the link without dropping connections. Finally, the active DWDM system is more scalable than the passive one, which makes more wavelengths to be multiplexed over the fiber. But one the other hand, there are also two main disadvantages of active DWDM system. One is the high cost of the active DWDM devices, and the other one is the complex installation.

In conclusion, the active DWDM system can offer greater capacity and higher scalablity, while the the passive DWDM system needs less cost and is easy to deploy. If the passive DWDM system meets your need, you’d better not to choose the active one as it will cost you very high. All in all, there is no the best, but the most suitable for your system. Just choosing the most suitable DWDM for your system according to what your network needs.

Polishing Tips and Best Practices for Single Fiber Connectors

When polishing a fiber optic connector, by polishing machine, there are procedures and setting parameters designed to leverage the machines best practices as well as previous developments and experience.

Additionally, there are tips to consider applying during daily production to improve first pass yield, efficiency and results to avoid scrapping costs.

The standard polishing process includes three steps:

Epoxy Removal

Geometry

Final Step: finishing the optical surface

Below we share tips for each step of the process:

Epoxy removal

Air Polish

When connectors are loaded on the jig after cleaving, there are large, sharp edge fibers and inconsistent fiber protrusion due to different fiber cleaves.  This can result in fiber breaks if polishing, by machine, is started immediately.

Tip: start polishing the connectors loaded on the jig with SC Film mounted on the rubber pad and then by hand/air delicately, with little hand pressure making few rotations (around 10).  Next the fiber protrusion has more consistent length distribution over all ferrules resulting in less fiber breakage (fiber into ferrule bore hole).  After this initial operation, one can start polishing with the machine using the same film used for air polishing.

LC Conical

The available surface of the 1.25 mm connector is small and sometimes due to this limited surface, epoxy is also going to the base of the chamfer area that you cannot remove using the polisher.

Tip: After the epoxy removal step on the polisher, if some epoxy is still present on the chamfer area, use a little scalpel to remove residues. This will allow to move to the next step (Geometry) avoiding any contamination on D films.

For other types of ferrule (2.0 or 2.5 mm) it is a good practice to check, after epoxy removal, if all the epoxy has been polished away (checking the front face of the ferrules).

Jig Locking Mechanism with Individual Ferrule

A jig where the ferrules are independently moving from the each other is called Individual Pressure Control (IPC) fixture and is recognized by the use of spring loaded adapters to lock and to keep the ferrule in place.

Tip: after checking if there are not any epoxy residues left, it is a good practice to verify if all the connectors are well positioned (same height) and if the spring of each adapter is working properly with the ferrule moving freely – not stuck due to polishing residue. This guarantees each ferrule will be under the defined polisher pressure in the polishing steps offering more consistent geometry results.

Geometry

Air Bubble Under Lapping Film

A common occurrence after positioning on the rubber pad is air bubbles under the lapping film.

When this occurs, it must be removed because during the geometry polishing process as the air cushion can modify the ferrule geometry (radius and/or apex).

Tip: to avoid this effect, use a roller to press down the lapping film on the rubber pad. It is important to have a different roller for each type of film to avoid contamination especially from D film to final film.  If one uses the same roller, it is essential to clean it before moving to the smaller film grid.

Tip: when using just one roller, to avoid contamination, take two films one on top of the other (one on top upside down) and then use roller. The lapping film that will used for polishing connector will not be effected by any cross-contamination.

D Film Longer Life

Diamond film is the most expensive film we use on the polishing process and one consideration when selecting a supplier is the number of times you can use it.   There are D films used for 10, 15, 25 times, or even longer depending on the process and specific customer specifications.

Tip: after a certain number of usage, typically 10 times, if you clean the surface with alcohol you are able to extend the life of this film (using alcohol removes debris from previous polishing).

VIEW: Diamond Films Product Matrix

Rubber Pad

In a polishing process, we use rubber pads typically 60 to 80/85 durometer.  Keeping consistent geometry can be a challenge.

In principle, a rubber pad that is too soft can help to reduce radius but effect negatively the apex.

Using a harder pad with higher pressure should be better to get positive radius and apex results.

Tip: always try to develop a process using pads with same durometer throughout the entire process. Changing the hardness of the pad will effect radius and/or apex and can make it difficult to bring both parameters within the specification.  Usually adjusting pressure and timing, using the same pad, can achieve desired results.  If you do need to change to a softer pad, decrease the durometer maximum by approximately 10 durometer.

APC Jig Choice According to Connector Style

In the market there are two different types of ferrules: Stepped and Conical.

As soon as you select the connector style, you need to consider the related jig.

Tip:

Stepped Ferrule – require a jig with an APC angle of 8°

Conical Ferrule – require a jig with an APC angle of 8.3°

FINAL STEP

CLEAN, CLEAN, CLEAN

Scratches are a fiber optic assembler’s nightmare because if it occurs, they jeopardize all of the previous activities and are costly due to the waste of time and additional material.

Tip: each step requires good cleanliness to avoid contamination especially when you move from D film to Final film.   Quite often this activity is underestimated but if you make this a priority, you can avoid costly issues.

Tip: use spray water to remove all the debris on the ferrule and mainly at the jig’s bottom surface.   Follow this by wiping the operation using Cleaning Wipes or similar paper moving from the center of the jig to the outside.

Final Film Choice

In addition to the nice smooth surface, final film is extremely important to define the right fiber protrusion.  Based on the requested specification, you can choose different types of film that provide various results.

Tip: important to know the different specifications and what your requirement is: Fiber protrusion, Undercut, Flatness with respect to the Ferrule.   Basically, fibers can protrude or stay below the ferrule surface according to the described parameter to guarantee the best fiber physical contact terminated in a connector.

Tip: if you don’t have access to different final films, adjusting time and pressure, can also achieve specified results with some limitations.

Fiber optics requires physical contact between the two mating parts because if you have an air gap between, it will cause high back reflection.  The physical contact will happen when you have fiber protrusion but considering the compression force made by the connectors, you could have some physical deformation of the fiber and ferrule.  When that happens, there is physical contact with flat and undercut if the related value are according to the specified parameters.

One might ask, why not only use protruding fiber and the answer is that concern is about fiber breaks when the two fibers are pushed against the others?   They specify undercut or flat fiber vs. end face the ferrule to better protect the fiber but still having physical contact.  It is clear the parameters have to be according to the specifications (as seen on the graphic) otherwise you will experience air gap.

Fiber Optic Polishing Fixture Maintenance

To help ensure consistent polishing results, maintenance of all fiber optic polishing equipment is essential.    The Preventive Maintenance program for polishing fixtures should include periodic ultrasonic cleaning.  This is true for any fiber optic polishing fixtures, regardless of connector or ferrule type:  connector fixtures with latching mechanisms (LC, SC), ferrule-only fixtures with screw caps or cam-locks, MT ferrule fixtures, etc.

All fixtures come from the factory with very precisely milled ferrule “bores”, tailored specifically to the particular ferrule which will be polished.  These bores position the ferrule to precise angles to the polishing surface—–90-degrees for PC polishing, other angles (typically 82-degrees, to create an 8-degree finish) for various APC polishing.  (Note:  I use the term “bore” for the circular holes milled into the fiber optic polishing fixture which hold the round ferrule, but the same concepts apply to fixture for rectangular ferrules such as MT.  For simplification, this discussion will reference typical round, PC-finished ferrules, but the concepts all apply to MT fixtures as well as APC fixtures).

The level of precision to which the fixture holds the ferrules determines many of the ferrule’s geometric characteristics (Apex, Radius, Fiber Height, Ferrule Angle, etc).   Contamination of the fixture can negatively affect this precision, by either pre-maturely wearing of the fixtures dimensions, or by creating buildup in the fixture, which prevents the ferrule from seating properly.

The contamination we are discussing here is primarily a natural result of the normal polishing process.  Ferrules are polished on abrasive films or flock-pile pads impregnated with abrasives.  During polishing, some of these abrasive particles, along with the ceramic or plastic material being removed from the ferrule itself, come free and mix with the water used as lubricant within the process.  This results in an abrasive slurry that contaminates the fixture and the ferrules themselves.  Common polishing practices require the operator to clean the bottom of the fixture between polishing cycles, to remove abrasive particles that may create fiber end-face scratches in subsequent polishing steps.  However, this slurry can (and will) migrate into crevices and the bores of the fixture—places difficult or unlikely to be fully cleaned or flushed out during normal the normal polishing process.  Allowed to dry, it will harden and cake.

The 4 major effects of this contamination to consider:

Contamination within the ferrule bore is wearing the bore, creating larger bore diameter:  Ferrule bore wear is unavoidable over time—as thousands of ceramic ferrules are inserted and removed from a stainless steel fixture, the bore will wear.   However, contamination of the bore, particularly with abrasive particles naturally resulting from the polishing process (the “slurry” referred to above), can accelerate this wear.  As the bore diameter becomes larger, the ferrule is held to less than 90-degrees to the polishing surface, resulting in larger Apex Offset and Angle values.

Contamination within the ferrule bore is building up, “pushing” the ferrule to one side:  the slurry generated from polishing can accumulate in the bore or other areas of the fixture, building up to prevent the ferrule from seating at precisely 90 degrees to the polishing surface.  This can also result in large Apex Offset and Angle values.  This buildup issue is often seen in MT ferrule polishing fixtures.

Contamination within the ferrule bore is preventing the ferrule from sliding freely within the bore:  This mainly applies to connector polishing (as opposed to ferrule-only polishing) where the connector’s spring force is relied on to present equal downward pressure to the ferrules during polishing.  The ferrules in a connector fiber optic polishing fixture must be able to piston up-and-down freely in the fixture.  If contamination of the ferrule bore holds the ferrule too tightly, this may “lock up” the ferrules or prevent them from pistoning consistently / smoothly within the bore during polishing.  This, in turn, will result in different pressures being applied to the end-faces during polishing—–which creates variation in Radius values, FH values, and fiber end-face polish quality (scratches).

Contamination on the fixture prevents ferrules from protruding equal distance from the base of the fixture. This mainly applies to fixtures for polishing ferrule only (as opposed to connector polishing).  The ferrules must protrude the same amount from the bottom of the fiber optic polishing fixture, to ensure consistent pressure being applied to all ferrules.  Contamination at the top of the bore, where the ferrule flange sits on, will cause the ferrules to sit higher and protrude less.   If ferrules are protruding different length from the bottom of the fixture, this results in unequal pressures being applied to the ferrules during polishing, again resulting in variation in Radius values, FH values, and fiber end-face polish quality (scratches).

Fiber Optic Polishing Fixture Maintenance Ultrasonic CleaningThe most effective way to reduce the effects of such contamination is to thoroughly clean the fixtures between use, by rinsing with distilled water immediately after polishing, to prevent the “surry” from drying.   Even so, particularly with fixture having many recessed faces or “nooks and crannies”, it is good practice to give each fixture a more rigorous cleaning after use, when the fixture will be not be in use for some time (such as at end of shift).  Ultrasonic cleaning, in combination with brush-cleaning the bores, works very well for this type of cleaning, and it is recommended that cleaning be part of a daily Preventive Maintenance program for all fiber optic polishing fixtures.

Ultrasonic Cleaning:

Ultrasonic cleaners are a bath into which the object to be cleaned is submerged.  The bath is usually of distilled water, which can be augmented with detergents or solvents or other cleaners.  For cleaning of polishing fixtures, an ultrasonic bath of only distilled water is sufficient, and recommended over other solutions.

The walls of an ultrasonic cleaner vibrate and a particular high frequency, transferring pressure waves to the water. These waves have the effect of pushing-and-pulling the water molecules to create “cavitation”:  essentially “tearing” the water molecules apart, creating a very short-lasting “bubble” of vacuum within the water, which very quickly—and forcefully—implodes. The energy of this collapse, which occurs near the surface of the submerged object, is what creates the agitation to remove contaminates from the surface.

Because the cavitation occurs within the water medium only, it is important that the entire object be submerged, with no air bubbles trapped in areas to be cleaned.  As long as the surfaces to be cleaned are in contact with the water, and because the cavitation happens on the molecular level, the cleaning effect can reach into very small crevices and is ideal for fiber optic polishing fixture cleaning.

It is important to note that the cavitation is created by physical movement of the side walls of the cleaner, and that most ultrasonic cleaners are calibrated such that most of the cavitation power occurs somewhere in the middle of the bath.  It is important that objects to be cleaned are suspended within the bath water, and do NOT contact the bottom or interior walls of the ultrasonic cleaner.   Objects contacting the bottom or sidewalls of the cleaner will reduce their movement, and thus reduce the cavitation effect.

Following up the ultrasonic cleaning with brushing of the ferrule bores and blowing dry with clean, compressed air will help to ensure maximum life and performance of the fiber optic polishing fixture.

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