Fiber Optic Blog | M2 Optics

Solving Optical Multicast Challenges

Posted by Kevin Miller on Mon, Mar 17, 2014 @ 18:03 PM

There are many scenarios in today’s networks that require the replication of an optical signal, also known as optical multicast. Some of those scenarios include video feeds or data streams that need to reach multiple endpoints simultaneously. In other scenarios an expensive 40/100Gbps port may need to be replicated. In either case, current multicasting solutions create potential problems associated with congestion, cost, and latency.

Problems with Existing Multicast Solutions

Multicast is a common feature of many switches with electrical backplanes, however, with data rates at 40Gbps and above, multicasting becomes an expensive and resource intensive endeavor. 100Gbps interfaces are still relatively expensive, so multicasting a 100Gbps signal adds significant cost.  In addition, multicasting 40/100Gbps signals in the electrical domain may rapidly exhaust the backplane resources. For example, a Layer 2/3 switch receives a 100Gbps signal over 4x25Gbps wavelengths. Once received, a gearbox is used to take the 4x25Gbps optical signals and convert them to 10x10Gbps electrical signals. Each of those signals has a dedicated lane within the backplane. So, if you want to multicast a single signal 8 times, 80 lanes will be required. When extrapolated multiple times, it is easy to see that even with Terabit backplanes congestion will likely occur.

Another area of concern with multicasting that exists in even lower speed 1-10Gbps networks is latency. Anytime a signal is taken from the optical domain to the electrical, some amount of delay in packet processing will be added, which creates latency. This can cost financial institutions $100s of millions of dollars every year. For video distribution, this can increase synchronization issues between multiple feeds.

Using SwitchLight to Overcome Multicast Challenges

Two of the strongest trends in networking today are 100Gbps networking and latency reduction. Since congestion can also be a cause of latency, the only way to avoid both of these problems is to move the multicasting function into the optical domain. The M2 Optics’ SWITCHLIGHT™ solution provides an efficient, low-latency approach for optical signal multicasting regardless of protocol, data rate, or fiber type.  Thus, it addresses a number of key areas that have been discussed:

Prevent congestion:  SWITCHLIGHT™ reduces the number of lanes needed for optical multicast and port replication in existing OEO (Optical-Electrical-Optical) switches.

Lower costs:  Using SWITCHLIGHT™ to replicate an expensive 40/100Gbps port decreases the per port cost of multicasting optical signals by eliminating the need to provide multiple 40/100Gbps interfaces.

Reduce latency:  SWITCHLIGHT’s all-optical solution eliminates the electrical conversion that OEO switches require to ensure that optical signals are multicast or replicated at the speed of light.

Lossless multicasting:  SWITCHLIGHT’s lossless multicasting is truly unique as it is the first all-optical, plug-and-play solution for optical multicast and/or port replication that can eliminate the added insertion loss associated with these functions.

Future-proof the network:  Being data rate and protocol agnostic, SWITCHLIGHT™ eliminates the need for upgrades for the foreseeable future. SWITCHLIGHT’s standard APIs also make integration into existing environments pain-free.

Optical Multicast Diagram


To learn more and discuss how the SWITCHLIGHT™ offers a cost-effective and resource efficient solution for optical signal multicasting and/or port replication, contact the M2 Optics team today.

Topics: optical switch, switchlight, optical multicasting, optical multicast, 100Gbps

Optical Switches: Symmetric and Asymmetric

Posted by Kevin Miller on Wed, Feb 5, 2014 @ 16:02 PM

While there are a number of aspects that can be discussed in regards to optical switching technology, the focus of this article is to provide information about two key categories of optical switches – symmetric and asymmetric.  The concept is very straightforward, but still important to understand when determining which type of optical switch will be most suitable for a given application.

Symmetric Optical Switches

Symmetric optical switches are defined as having an equal number of input (M) and output (N) ports (MxN, where M=N) and can vary in size from a 2x2 to a 320x320 or larger.  Symmetric switches are typically based on a non-blocking switch matrix providing a path from any input to any output, which permits any-to-any connectivity. While any-to-any connectivity enables all ports to be connected simultaneously, a single input can only connect to a single output.  So, if all ports are simultaneously connected and a connection needs to be changed, another connection must be disconnected to accommodate this change.

Symmetric Optical Switch

In terms of applications, symmetric optical switches are useful and better suited for a dynamic topology, where frequent changes are required for connecting to/with all network devices.  One of the most common applications is test environment automation, where the topology needs to change rapidly so that any port on a DUT can reach any test generator or analyzer.

Asymmetric Optical Switches

Just the opposite of a symmetric arrangement, asymmetric optical switches are defined as having an unequal number of input (M) and output (N) ports (MxN where M≠N).  An optical switch of this type could be as simple as a 1xn (where N>1), or an MxN (where M<N).  Common examples of these are 1x2 or 64x128.  Similar to symmetric switches, asymmetric optical switches also use a non-blocking switch matrix; however, the number of simultaneous connections is equal to the number of input ports.  For example, a 1xn can only have one connection active at a time; whereas, a 64xn can have 64 connections active at a time. Unlike a symmetric switch, many times a connection on an asymmetric switch can be changed without moving any other connections.

Asymmetric Optical Switch

This “any-to-any” (or one-to-any, in the case of 1xN) type of optical switch is ideal for static topologies that require protection switching, which can be done with one or more 1x2s. It is also useful in product test environments that require the ability to transmit a signal from one device to one of many others, where a larger 1xN duplex switch is needed.  One of the more common applications for asymmetric switches is network monitoring.  Network monitoring applications typically require an asymmetric switch to share a test or analysis tool on-demand across multiple devices and paths in the network.  In this scenario, the asymmetric switch generally accesses the network through taps to prevent the disruption of data between the source and destination.

Ultimately, when requiring an optical switch for any application, is it important to understand the types that are available to determine the most suitable solution.  If you wish to learn more, or wish to discuss the right type of optical switch for an application, the M2 Optics team is always available to offer assistance and expertise at your convenience.


View the Most Flexible Optical Switching Platform





Topics: network monitoring, optical switch, optical switches, optical switching, symmetric optical switches, asymmetric optical switches, non-blocking switch, switchlight

Are Your CATV Laser Transmitters Optimized for Maximum Performance?

Posted by Kevin Miller on Tue, Sep 10, 2013 @ 16:09 PM

As a provider of Optical Modulation Index (OMI) Instruments used for optimizing laser transmitter performance, our organization has the opportunity to work closely with many of the talented technicians and engineers at the leading CATV operators around the world.  As a result of the many discussions related to both the importance and use of OMI for maximizing system performance, there have been a number of consistent topics we have seen regarding the deployment of transmitters in the network.

One question that always comes up from engineers when discussing why they need to use an OMI instrument is:  "When I purchase a new transmitter from our vendor, shouldn't it already be optimized for maximum performance? "  In theory this is correct, but in reality, this is not often the case when it is deployed, due to a number of variables.  This is not to say that the transmitter you purchased is not a great device, as there are many models available from the most reputable vendors that deliver high quality equipment.  However, there is almost always room for improvement, from an optimization perspective, to get the most out of that particular transmitter.

Variables That Can Lead to Non-Optimization 

Before a laser or transmitter is shipped, it goes through a number of processes and specification-setting procedures. All of these procedures are prone to inaccuracies that, in the end, can and often add up to a major shift in performance.

Laser OMI is determined and specified by the laser manufacturer

Variable - manufacturers typically use un-modulated carriers
Variable - manufacturers set the specification using a specific number of channels, which is almost never the exact channel setting of the end-user, given that every live network is unique in terms of total channel counts, analog-to-digital ratios, etc.

Lasers are purchased and installed by the transmitter manufacturer

Variable - laser driver circuits introduced between the input and laser
Variable - transmitter manufacturers typically use un-modulated carriers
Variable - transmitter manufacturers typically do not openly divulge the OMI for the device. Usually the RF per channel level necessary to drive the transmitter is given.  Since manufacturers want to ensure the transmitter will work for a variety of scenarios in each unique CATV network, this provides a buffer for any variations normally encountered in manufacturing optical equipment.

Transmitters sometimes have front panel “set up” indicators

Variable – the circuit tolerances can cause the OMI setting window to shift, becoming smaller or larger, and thereby allowing the OMI setting to have a fairly wide range

The final result is that the user sets the RF input level for the number of channels used. This may be a change from the original OMI/channel setting. With modulated carriers and all of the above other variables, the setting is almost certain to not be optimal.

In fact, in most deployments where the FOS 1000A OMI instrument has been used for the first time, the majority of laser transmitters are under-driven, with a total OMI value in the 13 to 17 range. A good DFB laser that is optimized typically results in a total OMI value in the 19 to 25 range.  In these cases, while the under-driven total OMI value may be a "safe" number, there is a lot of room for improvement in terms of achieving the best performance from your lasers.  

Since you have made the investment in a high quality laser transmitter, it only makes sense to take the extra step to maximize their value.  A healthy system leads to happy subscribers, which is a key goal of any CATV operator.

Learn More About OMI & Optimizing Laser Transmitters:

OMI Whitepaper      Technical Whitepaper - "Defining OMI"
 FOS 1000A OMI Instrument      FOS 1000A OMI Instrument

Topics: m2 optics, optical modulation index, omi, laser transmitter, fos 1000a, catv transmitter, catv laser

Mobile Backhaul - Strategies for Increasing Bandwidth to Cell Sites

Posted by OJ Johnston on Mon, Jul 22, 2013 @ 17:07 PM

As the use of mobile applications and services that require increasingly more bandwidth continues to grow, wireless service providers must find cost-effective and efficient methods for meeting the bandwidth demand. Legacy transport networks are no longer capable of adequately serving today’s cell sites. Newer technologies such as GPON, WDM-PON, and Ethernet over CWDM/DWDM are all well-suited to cost-effectively address the growing bandwidth needs of wireless service providers. Regardless of the technology used, M2 Optics’ SplitLight product is an integral part of the solution.


While GPON has been adopted as a technology of choice in high-speed access networks for inexpensive residential service delivery, more recently, it has begun to spread into business access.  With the ability to deliver up to 10Gbps per GPON port, it can also be a cost-effective technology for delivering higher bandwidth to cell towers.


Figure 1: GPON Network


Whether the GPON splitters are collocated with the OLT or distributed in the field, it is likely that a multiple of splitter modules would be needed to handle each serving area.  To aid with this, the SplitLight HD can provide up to 16 GPON splitters in a single, 1RU chassis, while traditional solutions can only provide a single GPON splitter in the same footprint. In addition, legacy LGX solutions would require at least 4RU to deliver the same density.


Building on the advantages of GPON, shared infrastructure and a single OLT transponder, WDM-PON provides the added advantage of delivering a dedicated wavelength to each ONT. Unlike GPON, WDM-PON does not use a splitter. Instead, an Arrayed Waveguide Grating (AWG) is used to multiplex and de-multiplex wavelengths between the feeder fibers and distribution fibers. The result is dedicated bandwidth and a more secure network for each subscriber, or in this case, cell tower. Another advantage of WDM-PON is the ability to add/drop wavelengths at intermediate cell towers that lie between mobile switching centers.


Figure 2: WDM-PON Network

As with GPON splitters, it is likely that multiple AWGs would be required at both ends of the WDM-PON network. The SplitLight HD can also house up to 12 AWGs in a single, 1RU chassis. In addition, the SplitLight HD has the flexibility to also house passive OADMs for the intermediate add/drops.

Ethernet over CWDM/DWDM

Of course, one of the best ways to increase bandwidth to fiber-served cell towers is to simply increase the bandwidth capacity by delivering multiple wavelengths to sites that are approaching network saturation. The simplest way to do this is to use passive CWDM and DWDM multiplexers/de-multiplexers.

Ethernet CWDM DWDM

Figure 3: Ethernet over CWDM/DWDM

As with WDM-PON, passive OADMs (Optical Add-Drop Multiplexers) can be used to add/drop one or more wavelengths at cell towers between mobile switching centers.


Figure 4: OADM Function

Similar to the other technologies previously mentioned, M2 Optics’ SplitLight HD is capable of providing both the CWDM/DWDM muxes as well as the passive OADMs. Up to 16 mux/OADM modules can be housed within a single SplitLight HD chassis.


As mobile data traffic continues to increase, carriers must find the most cost-effective and efficient solutions for delivering bandwidth to each tower. Technologies that allow for a shared infrastructure enable carriers to realize a more immediate ROI. However, proven solutions for FTTH, such as GPON, might not be enough for mobile backhaul due to their shared bandwidth, which will likely experience more contention for bandwidth even on 10G GPONs. In such cases, WDM-PON or Ethernet over CWDM/DWDM solutions could be the answer. Regardless of the underlying technology, SplitLight can accommodate any passive optical networking need in the most cost-effective and efficient manner.


Learn More about SplitLight

Topics: WDM-PON, GPON, SplitLight, m2 optics, cwdm, dwdm, mobile backhaul, wireless backhaul, oadm

Enterprise and MDU/MTU PON – Rack’em, But Don’t Stack’em

Posted by OJ Johnston on Tue, Apr 9, 2013 @ 17:04 PM

Currently, one of the challenges in deploying new, higher speed services to both enterprise customers as well as MDU/MTU customers is how to deliver these services using the least amount of space possible, while maintaining network flexibility and service quality.  M2 Optics’ recent release of the SplitLighttm High-Density Platform (HDP) enables unprecedented space savings and enhanced flexibility without sacrificing performance.

Size Matters!

As previously introduced in a recent article, the SplitLighttm HDP form-factor offers the most density available in a single RU for optical combiners/splitters (up to 192 each 1x2, 128 each 1x4, or 16 each 1x32) through its patent-pending, 3D architecture.  In addition to combiners/splitters, the SplitLighttm HDP can also house passive optical wavelength multiplexers (mux) and demultiplexers (demux).  In fact, it can house up to 16 of these mux/demuxes.  Furthermore, the SplitLighttm HDP can be configured to support both applications simultaneously within a single chassis.  As a result, in just 1RU of space, GPON, 10G GPON, WDM-PON, and network monitoring applications can all be supported from a single chassis.  Typically, this scenario would have required the following:

  • A patch panel with integrated tap for monitoring at the service demarcation point

  • GPON splitter shelf (3 or 4RUs) or wall mount cabinet combiners/splitters to split the signal from the feeder fiber onto the distribution fibers

  • WDM mux/demux, which may fit in the splitter shelf or may be a separate shelf (another 3 or 4 RUs)

By using the SplitLighttm HDP, all of these functions can be accomplished in a single chassis, reducing the required rack space from as many as 4-6 RUs or more down to just 1RU.  M2 accomplishes this by using MTP connectors to reduce the front panel space needed for connectors and the patent-pending 3D architecture of the system.

GPON and WDM-PON Diagram
Figure 1:  GPON or WDM-PON Using SplitLighttm

Doing More with Less – Future Proofing The Network

In today’s business environment, companies are being forced to do more with less. As previously mentioned, the SplitLighttm HDP allows companies to simultaneously tap signals for network monitoring, split signals to provide access via the GPON, and/or demux the wavelengths to provide access via the WDM-PON. Combining the functionality of multiple passive network elements into a single network element decreases the size without limiting flexibility. In addition, the SplitLighttm HDP can provide front panel, rear panel, or both, connectivity with customized labeling. The connectivity flexibility coupled with the 3D architecture of the SplitLighttm HDP, enables companies and service providers to have even more flexibility in future-proofing their networks.

WDM-PON and GPON Through SplitLight
Figure 2:  Both GPON & WDM-PON Using SplitLighttm

Optimum Performance

M2 Optics’ SplitLighttm HDP uses low-loss components, including official US Conec MTP Elitetm connectors. Using bend-insensitve fiber and MTP Elite connectors coupled with M2 Optic’s comprehensive testing ensures the lowest possible loss across all connections while providing the size and functionality benefits previously mentioned. As a result, the SplitLighttm HDP surpasses the capabilities of all other solutions in the market.

The Ultimate Solution

Using a single chassis with the integrated taps for network monitoring, GPON combiners/splitters, and WDM-PON mux/demux provides unmatched flexibility and density in a single 1RU platform. Couple these attributes with high performance components and the SplitLighttm HDP delivers the ultimate solution for today’s high-bandwidth, enterprise and MDU/MTU PON networks.


SplitLight PON Splitters

      Learn More about SplitLight  


Topics: PON, WDM-PON, GPON, 10G GPON, PON splitters, MDU PON, SplitLight

Get The Most Out Of Bare Optical Fiber Spools

Posted by Kevin Miller on Thu, Apr 4, 2013 @ 17:04 PM

If your company is like most that are involved with building or utilizing fiber optic systems, chances are you have a few spools of bare optical fiber laying around the lab.  Since it is critical to ensure fiber-based equipment works as intended prior to deployment in the field, it is a recommended and common practice for engineers to simulate networks using spools of bare optical fiber.  Because there have been a variety of different fibers available over the years, engineers can end up with fair amount of spools at their disposal.

As a leading provider of packaged optical fibers for over a decade, our team at M2 has come across a lot of different setups for working with optical fibers in the testing environment.  While we often assist customers with new fiber requirements, we also receive a lot of inquiries that say something to the extent of “I already own a lot of fiber, but I am not seeing consistent performance, how can I improve this?” or “We have fiber spools, but I’m not 100% certain what type they are and/or if any may be damaged – can you help?”  As a result, we wanted to share a few straightforward tips and practices that one can follow in order to ensure you get the most out of your fiber spools.

Invest in a Quality Fiber Spool Enclosure

While your first reaction to the above statement may be to cringe at the idea of having to spend money, the word “invest” is used because taking this action is both a necessary step and one that will provide long-term benefits.

Most engineers will prefer to use a high quality testing platform, but we’ve seen quite a few eye-opening, makeshift setups from exposed fiber hanging from a shelf in the ceiling to spools sitting on the floor in cardboard boxes – all of which the engineers admitted were not the most ideal setups.  In many cases taking this step also requires convincing others, so here are some reasons why the most reputable test labs always follow this best practice:

  • A quality enclosure will protect against damage to both the fiber itself and the connectors, which occurs pretty regularly when using and handling unsecured fiber spools.  By protecting the fiber from breaks or bends (which are not often easily visible), you can ensure that your fiber will offer consistent performance over the long-term.

  • Optical fibers are more easily identified and organized when packaged into a suitable enclosure.  In this manner, you know what you are working with and do not have to waste time finding and trying to determine that what you are using is indeed the correct optical fiber.

  • A quality enclosure offers a more professional look, which is something not always considered when using optical fibers.  Many test labs often receive visitors, from business partners to customers, so it is important to have a nice setup.  When your most important customer comes to see a new product that you claim will meet their requirements, which will give them more confidence – a bunch of spools laying on a bench with exposed fibers all over, or an organized rack or shelf setup?  The answer is clear and this does in fact make a difference to people.

Ultimately, it comes down to the question “do I invest a little bit extra now, or do I run the risk of having to invest a lot more later if/when we have an issue?”  By making the extra investment now, you will be a lot happier knowing that you are getting results that you can rely on, while improving testing practices in the lab.  In addition, a quality vendor will be able to work closely with you to determine and customize the most ideal setup for your requirements, while offering a number of enclosure types for you to choose from.

Bare Optical Fibers
Always Clean the Connectors

Since there is so much information out there as to why connectors should always be clean, I won’t go into too much detail on this topic.  This should be a common practice of anyone working with fiber optic equipment and it is no different when testing with your optical fibers.  Even when your optical fiber is protected in an enclosure and you have followed all other best practices, a dirty connector will still lead to undesired results.  There are a number of very useful cleaning devices that make it quick and easy to clean the connectors of your fiber spools and connection cables, so always incorporate this into your testing procedures.

By following these practices, it will go a long way to ensuring that you are getting maximum benefit out of your optical fiber spools, whether they are brand new or ones that you already own.



   Download Free Whitepaper

   Best Practices for
   Simulating a Physical Fiber Network


Topics: optical fiber, optical fibers, fiber spools, optical fiber spools, bare optical fiber

Passive Optical Networks – Moving Beyond the LGX Form-Factor

Posted by OJ Johnston on Wed, Apr 3, 2013 @ 17:04 PM

Traditionally, products have gone down the path of modularity for two reasons: cost and/or ease of replacement without effecting existing services.  When the LGX form factor was first created for optical splitters, it made sense to have a modular approach for the first reason and to a lesser extent, the latter reason.  When optical splitter modules were first put into the LGX form factor, the cost per splitter was considerably higher than it is today. Therefore, inserting modules into a chassis became a cost effective way to “grow” as needed.  At the same time, the quality of those modules was not as high nor as repeatable as it is today, so despite any changes being service effecting (passive elements are not capable of protection switching around an outage) having the ability to replace the modules was also a key advantage.

Current Requirements & Challenges

Today, the cost of optical splitters has significantly dropped while the quality has improved, negating the previous advantages of the LGX form factor.  In fact, as networks grow exponentially in bandwidth, they are decreasing exponentially in physical footprint due to virtualization and cloud technologies.  The driving factors behind this market shift have been related to the space available for service providers and data centers to offer the services their customers need.  For this reason, the LGX form factor no longer works.  Taking up 4RUs in a rack (at a minimum) is unacceptable for passive elements in today’s networks, yet this is what is required for a modest number of LGX splitter modules.  Even with the maximum number of optical splitter modules installed in the highest density 4RU LGX rack, the total number of splitters is limited to only 128.

The Solution

Recognizing this market shift, M2 Optics has recently launched its SplitLightTM High-Density Platform (HDP) family of products. Each platform, or chassis, is only 1RU. Unlike, traditional approaches that have bulkhead modules, the SplitLightTM HDP uses a patent-pending 3D approach to provide the industry’s most dense solution in a single rack unit. As a result, up to 192 splitters can be installed in a single, SplitLightTM HDP.  While the SplitLightTM HDP provides significantly more density per RU than an LGX solution, it also maintains the flexibility of those solutions in terms of chassis depth, flexible mounting options, and both front and rear connector customization.


SplitLight Optical Splitters

      Learn More about SplitLight  


Topics: SplitLight, fiber optic splitters, m2 optics, optical tap, fiber tap, optical splitters, passive optical network, lgx, pon splitter

Best Practices for Network Monitoring Traffic Capture

Posted by OJ Johnston on Thu, Dec 20, 2012 @ 18:12 PM

In recent years, companies have shown the benefits of “copying” and sending traffic from network backbones to purpose-built monitoring devices…no interference with the existing, “live” traffic and the traffic can be analyzed in real-time or stored for later playback. However, the best approaches to “copying” and sending the traffic to be monitored has been a source of contention.  As 40/100G becomes more prevalent, how the traffic is accessed will become increasingly important.

Initially, the Switched Port Analyzer (SPAN) ports were used to deliver copies of traffic to analyzers, but this has posed several problems at the 1G and 10G data rates, which likely will increase exponentially with 40/100G:

  • SPAN ports are part of the switch/router and operate in much the same way as typical ports, so the data is not always an exact copy
  • Traffic congestion both on the router and on the SPAN port itself can result in increased latency or the traffic to be dropped completely
  • Relying on a device that could be creating the problem to help identify it can be a self-defeating exercise

Network Traffic Capture 1

Figure 1: Network Monitoring with SPAN Ports

The practice most recently deployed, uses passive taps to send an exact copy of the traffic to the analyzer(s).  While this accomplishes the task of not interfering with the “live” network, it presents issues in terms of cost and data accessibility. For example, if a network has 10x10Gbps backbones that require monitoring, the network must also have 10 analyzer ports available for the monitoring. That may not seem that daunting at first, but suppose you are a service provider or data center and you have 144/288 fibers that require monitoring. Now, you need that many analyzer ports as well, which are expensive even at 10Gbps, so what happens when the customer migrates to 40/100G?

Network Traffic Capture 2

Figure 2: Network Monitoring with Passive Taps

Of course, a practical approach to this issue would be to connect the “monitor” ports from the tap, storage device ports, and a few analyzer ports to a patch panel. If a 1x3 tap is used (creates two monitoring ports for each backbone), all of the traffic can be stored for replay using one of the monitoring ports, and the analyzer(s) can be patched into the other monitoring port as needed. This enables all traffic on the network backbones to be captured while simultaneously monitoring the most critical paths (the paths of most interest) in real-time.

Network Traffic Capture 3

Figure 3: Network Monitoring with Passive Taps and a Patch Panel

While the approach above does solve the problem of capturing everything and reducing the cost of the analyzing equipment, it does present one key problem: manually patching in the storage device or backbone that you want to monitor can be time consuming, error prone, and increase the risk of creating a network issue. Using a Layer 1 switch or an automated patch panel can eliminate or reduce these issues. For example, connecting the “monitor” ports from the tap to a Layer 1 switch or an automated patch panel reduces the time needed to make connections because now they can be made remotely and at the click of a mouse. Furthermore, using a switch or automated patch panel reduces errors as generally some intelligence keeps the user from making an inappropriate connection (software may be intelligent enough to prevent a 10G port connection to a 100G port). In addition, making the connections inside the switch or automated patch panel reduces exposure to the elements preventing network errors that can occur, such as dirt on the end of a fiber optic connector.

Network Traffic Capture 4

Figure 4: Network Monitoring using Passive Taps and Symmetrical Switch

Ideally, the Layer 1 switch or automated patch panel would be used to “patch” either a monitor port directly from the network or a storage device port to the analyzer as needed. As a result, one of the “monitor” ports can be statically connected through a patch panel to the storage device’s Rx port. In this case, all of the storage device’s Tx ports and the other “monitor” ports from the tap should be connected to the input ports on the Layer 1 switch or automated patch panel. With that in mind, the output ports of the Layer 1 switch or automated patch panel should be connected to the Rx port(s) on the analyzer. This approach further reduces the cost of capturing the traffic on the network because it requires a patch panel, a passive optical tap, a highly asymmetrical Layer 1 switch or automated patch panel, and only a handful of analyzer ports. The cost savings of this approach versus the previous one above is primarily due to the asymmetrical Layer 1 switch or automated patch panel cost versus a symmetrical switch.

Network Traffic Capture 5

Figure 5: Network Monitoring using Passive Taps and Asymmetrical Switch


In summary, as we move toward 40/100G networks, the same problems seen in monitoring networks at 10G still exist but are compounded with the additional cost and complexity associated with 40/100G. The best and most cost-effective approach to ensuring that all data is quickly, reliably, and easily captured is to deploy passive optical taps coupled with either optical switches or automated patch panels, which connect the network backbones to storage devices and network analyzers.


Topics: network monitoring, 100G, network tap, traffic capture, analyzer port, passive optical taps, layer 1 switch, ethernet tap, network traffic analyzer

OTDR Training Using a Fiber Lab

Posted by Kevin Miller on Wed, Nov 14, 2012 @ 14:11 PM

Learning to operate an OTDR properly is a very important skill for technicians at companies managing and servicing fiber optic networks.  The OTDR is used frequently to determine length and loss characteristics, as well as for testing optical fibers for faults and related issues that can negatively affect network performance.

There are a number of different types of OTDR devices in the market, from small portable units designed for field use, to sophisticated laboratory-grade devices that can provide a wide range of features intended for the most advanced users.  Regardless of the type of OTDR itself, the one complimentary item that is always required for training is a length of test fiber.  (Note:  An OTDR launch fiber may also be required for overcoming the “dead zone” of a fiber-under-test, which is covered here).

While most training classes will use lengths of fiber on unsecured spools or in makeshift types of enclosures, this is generally not “best practice” as the delicate fiber is frequently at risk of damage, and often not very easy to handle.  Considering that the test fiber will be used by many students over time, it is a benefit to most classes to use a more professional solution for OTDR training.

By utilizing one of the many Fiber Lab solutions for OTDR training from M2 Optics, instructors and students both receive a number of benefits not available when using a traditional, unsecured fiber spool.  For convenience, we have outlined a number of key benefits below.

Key Benefits of Using a Fiber Lab for OTDR Training:

  • Easy-to-handle, stable enclosures protect fiber from accidental damage while providing consistent results

  • Any type of fiber is available, as well as any custom length, for simulating a number of different network scenarios

  • Fiber can include user-specified attenuations that represent field splices, good or poor connectors, or other “events” that a student must learn to identify with an OTDR

Ultimately, a Fiber Lab provides every student with a real optical network in an efficient package, customized to include common events that they will experience in live networks.  For the instructors, it is a great value to have a handy tool that can be used for teaching demonstrations, as well as testing students to ensure they have learned the OTDR skills necessary to be successful.  Lastly, instructors do not have to spend time attempting to build their own solution when an ideal platform is already available.

OTDR Training Solution  

Topics: otdr, m2 optics, fiber spool, test fiber, otdr training, otdr launch fiber, fiber optic training, fiber lab

Reducing Rack Space with New, High-Density Optical Taps

Posted by OJ Johnston on Mon, Oct 15, 2012 @ 17:10 PM

As virtualization and cloud applications become more and more prevalent in Data Centers, POPs, Head-ends, and Central Offices, the available rack space needed to house the equipment for these applications is shrinking.  While the space needed to store, process, route, or switch the data becomes more compact, one thing that remains difficult to reduce is the physical layer infrastructure. As traffic enters or exits a facility, most providers want the capability to monitor what is being delivered or sent to/from their site. At the larger sites, this data traffic is riding on fiber, and in many cases, there are a number of fibers coming into or out of a given site. To be able to accurately monitor this traffic, a passive optical tap is used to duplicate the traffic and send it to a monitoring device that can analyze the header information native to the traffic type.  In the past, these optical taps were relatively expensive and bulky. Even today, most vendors cannot provide more than 24 taps in a single 1RU footprint. 

For most companies, the ideal scenario would be to not only have a lower cost, higher density optical tap solution, but also one that offers adequate customization for flexibility.  For example, in some cases a company may want a 50:50 optical power tap ratio, while another may want a 90:10 ratio. Or, a company may have multiple monitoring devices each serving a different purpose, so more than a 1x2 splitter/coupler is required.  Furthermore, some applications require single mode optical fiber, while others require multimode fiber, thus it is crucial to have a solution that can meet a wide array of requirements.

While the common approach has always been to add more chassis in order to meet varying levels of customization and/or higher density requirements, this is not a viable option when rack space is at a premium.  Fortunately, some vendors have re-thought this situation and developed a new generation of optical tap solutions.  As an example, the SplitLight HD from M2 Optics can accommodate up to 128, 1x2 splitters of varying power ratios and fiber types in single 1RU chassis.  Compared to a traditional alternative with 10-20 total optical taps, this new solution can easily reduce the rack space required by 75% or more.  How is this possible?  Unlike most traditional optical taps which are very limited as a result of using standard connectors (LC or SC type), the SplitLight HD was designed in a unique way to incorporate multi-fiber MTP® connectors, which results in a much higher density in the same physical space.



With the increasing need for more sophisticated communications equipment to meet market demands, it is crucial that companies deploying and managing optical networks utilize solutions that help to maximize system performance, while also addressing equally important, related issues like rack space usage.  By doing this and aligning themselves with partners that understand the challenges they face, these companies can continue to deliver high quality services for years to come.

Topics: optical fiber, SplitLight, m2 optics, optical tap, fiber tap, optical taps, network tap, optical splitter, high density