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Optical Transceiver Modules

  • Introduction to Small Form-factor Pluggable (SFP) Transceiver Modules

    Introduction to Small Form-factor Pluggable (SFP) Transceiver Modules

    What Is SFP?
    SFP, short for small form-factor pluggable is a compact, hot-pluggable transceiver used for both telecommunication and data communications applications. SFP transceiver can be regarded as the upgrade version of GBIC module. Unlike GBIC with SC fiber optic interface, SFP is with LC interface and the main body size of SFP is only about half of GBIC so that it can save more space. SFP interfaces a network device mother board (for a router, switch, media converter or similar devices) to a fiber optic or copper networking cable. Meanwhile, SFP is a popular industry format supported by many network component vendors. It is designed to support SONET, Gigabit Ethernet, Fibre Channel, and other communications standards.

    The SFP transceiver is not standardized by any official standards body, but rather is specified by a Multi-source Agreement (MSA) among competing manufacturers. The SFP was designed after the GBIC interface, and allows greater port density (number of transceivers per cm along the edge of a mother board) than the GBIC, which is why SFP is also known as mini-GBIC. The related Small Form Factor transceiver is similar in size to the SFP, but is soldered to the host board as a through-hole device, rather than plugged into an edge-card socket.

    However, as a practical matter, some networking equipment manufacturers engage in vendor lock-in practices whereby they deliberately break compatibility with "generic" SFPs by adding a check in the device's firmware that will enable only the vendor's own modules. For example, in 2003 during a routine Internet Operating System (IOS) update on their Catalyst line of switches, Cisco added a feature that would cause the switch to reject optical modules that were not deemed "Cisco brand".

    Types of SFP Transceiver Modules
    SFP Transceivers are available with a variety of transmitter and receiver types, allowing users to select the appropriate transceiver for each link to provide the required optical reach over the available optical fiber type (e.g. multi-mode fiber or single-mode fiber).

    In the market, SFP transceiver modules are commonly available in several different categories:

    For multi-mode fiber, with black or beige extraction lever
    SX - 850 nm, for a maximum of 550 m at 1.25 Gbit/s (Gigabit Ethernet) or 150m at 4.25 Gbit/s (Fibre Channel)

    For single-mode fiber, with blue extraction lever
    LX - 1310 nm, for distances up to 10 km
    EX - 1310 nm,for distances up to 40 km
    ZX - 1550 nm, for distances up to 80 km
    BX - 1490 nm 1310nm, for distances up to 10 km
    1550 nm 40 km (XD), 80 km (ZX), 120 km (EX or EZX)

    For copper twisted pair cabling
    1000BASE-T - these modules incorporate significant interface circuitry and can only be used for Gigabit Ethernet, as that is the interface they implement. They are not compatible with (or rather: do not have equivalents for) Fibre channel or SONET.

    For WDM (Wavelength Division Multiplex) system
    BiDi SFP (Bidirectional SFP) for bi-directional traffic on a single fiber. Coupled with CWDM (Coarse Wavelength Division Multiplexing), these double the traffic density of fiber links
    CWDM and DWDM (Dense Wavelength Division Multiplexing) transceivers at various wavelengths achieving various maximum distances

     Applications of SFP Transceiver Module
    SFP is expected to perform at data speed of up to five gigabits per second (5Gbps), and possibly higher. Because SFP module can be easily interchanged, so electro-optical or fiber optic networks can be upgraded and maintained more conveniently than that with traditional soldered-in modules. Owing to its low cost, low profile and the ability to provide a connection to different types of optical fibers, SFP transceiver can result in a substantial cost savings, both in maintenance and in upgrading efforts. SFP transceiver is available with multi-mode single-mode fiber optics, allowing users to select the appropriate transceiver for each link in order to provide the required optical reach over the available optical fiber type. It is also available with copper cable interfaces, which allows a host device designed primarily for optical fiber communications to communicate over unshielded twisted pair networking cables. Modern optical SFP transceiver supports DDM (Digital Diagnostics Monitoring) functions, also known as DOM (Digital Optical Monitoring). This feature gives users the ability to monitor the real-time parameters of SFP transceiver, such as optical output power, optical input power, temperature, laser-bias current and transceiver supply voltage.

    Click on Link to buy Compufox SFP Transceivers

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  • Migrate to a 40-Gbps Data Center with Cisco QSFP BiDi Technology

    What You Will Learn

    This document describes how the Cisco® 40-Gbps QSFP BiDi transceiver reduces overall costs and installation time for customers migrating data center aggregation links to 40-Gbps connections.

    As a result of data center consolidation, server virtualization, and new applications that require higher data transport rates, the data center network is shifting to 10 Gbps at the access layer and 40 Gbps at the aggregation layer. A broad portfolio of high-performance and high-density 10- and 40-Gbps Cisco Nexus® Family switches is available at attractive prices for this transition. However, to support 40-Gbps connectivity, data center architects are challenged by the need for a major upgrade of the cabling infrastructure, which can be too expensive or disruptive to allow data centers to quickly adopt and migrate to the 40-Gbps technology.

    Cisco solves this problem with innovative 40-Gbps Quad Small Form-Factor Pluggable (QSFP) bidirectional (BiDi) technology that allows reuse of existing 10-Gbps fiber infrastructure for 40-Gbps connections.

    Challenges with Existing 40-Gbps Transceivers

    Standard short-reach (SR) 10- and 40-Gbps transceivers use fundamentally different connectivity formats, requiring fiber cabling infrastructure to be redesigned and replaced. 10-Gbps SR transceivers operate over dual-fiber multimode fiber (MMF) with LC connectors, and 40-Gbps SR protocols, such as SR4 and CSR4, operate over MMF ribbon with MPO connectors. As a result, 40-Gbps MPO-based SR4 transceivers cannot reuse aggregation fiber infrastructure built for 10-Gbps connectivity.

    Connector type is not the only concern. Whereas 10-Gbps SR transceivers require 2 fiber strands per 10-Gbps link, 40-Gbps SR4 and CSR4 transceivers require a theoretical minimum of 8 fiber strands, and often 12 fiber strands in practice. The reason for this requirement is that 40-Gbps SR4 and CSR4 use 4 parallel fiber pairs (8 fiber strands) at 10-Gbps each for a total of 40-Gbps full duplex, as shown in Figure 1. However, both use MPO-12 connectors, which terminate 12-fiber ribbons. As a result, 4 fiber strands in each connection are unused and wasted.

    To economize trunk fiber in a structured cabling environment, a 2 x 3 MPO fiber conversion module could combine three SR4 links onto two 12-fiber ribbon cables. But even then the 40-Gbps SR4 trunk still uses 8 fiber strands per link compared to 2 fiber strands in the case of 10-Gbps SR.

    At best, the connector change and increased fiber density needed for SR4 require a significant cable plant upgrade, making it expensive and disruptive for customers to migrate from 10-Gbps connectivity to 40‑Gbps connectivity in their existing data centers.

    Figure 1.      Concept of Existing 40-Gbps Transceivers: Of the 12 Fiber Strands Terminated by MPO-12 Connectors, 8 Fiber Strands (4 Fiber Pairs) Carry Traffic and 4 Are Unused


    Solution with Cisco 40-Gbps QSFP BiDi Transceiver

    The Cisco QSFP BiDi transceiver, shown in Figure 2, transmits full-duplex 40-Gbps traffic over one dual-fiber LC-connector OM3 or OM4 MMF cable. It provides the capability to reuse 10-Gbps fiber infrastructure. In other words, it enables data center operators to upgrade to 40-Gbps connectivity without making any changes to the previous 10-Gbps fiber cable plant.

    Figure 2.      Cisco QSFP BiDi Transceiver (QSFP-40G-SR-BD)


    The Cisco QSFP BiDi transceiver has two 20-Gbps channels, each transmitted and received simultaneously over two wavelengths on a single MMF strand. The result is an aggregated duplex 40-Gbps link over a MMF duplex LC-terminated fiber cable. The connection can reach 100 meters on OM3 MMF or 150 meters on OM4 MMF, which is the same as 40-Gbps SR4. Figure 3 shows the technology concept of the Cisco QSFP BiDi transceiver.

    Most Cisco switching and routing products that support 40 Gigabit Ethernet interfaces support the Cisco QSFP BiDi transceiver. For a complete list of supporting products, refer to the Cisco 40 Gigabit Optical Transceiver product page at

    Figure 3.      Concept of Cisco QSFP BiDi Transceiver


    Savings with Cisco QSFP BiDi When Migrating from 10 Gbps to 40 Gbps

    This section presents two case studies that demonstrate the savings achieved by using Cisco QSFP BiDi technology for 40-Gbps connectivity in data center networks. The case studies show how Cisco QSFP BiDi technology can remove the cost barriers for migrating and expanding the existing 10-Gbps cabling footprint to 40-Gbps infrastructure to provide the higher data rate in the data center network.

    Case Study 1: 288 x 40-Gbps Connections with Unstructured Cabling

    In an unstructured cabling system, devices are connected directly with fiber cables. This direct-attachment design can be used to connect devices within short distances in a data center network. As shown in Figure 4, direct connection between two 40-Gbps devices can be provided by MMF cables with either QSFP SR4 or QSFP BiDi transceivers at two ends.

    Figure 4.      Direct 40-Gbps Connections


    The QSFP SR4 transceiver uses MPO-12 connectors, whereas Cisco QSFP BiDi uses LC connectors. Existing 10-Gbps connections commonly are MMF cables with LC connectors. Therefore, with QSFP SR4 transceivers, none of the existing 10-Gbps MMF cables can be reused because the connector types are different. Cisco QSFP BiDi allows cable reuse, resulting in zero-cost cabling migration from direct 10-Gbps connections to direct 40-Gbps connections.

    Table 1 summarizes the costs and savings of migration and new deployment of 288 direct connections. To migrate the existing 288 10-Gbps connections to 40-Gbps connections, Cisco QSFP BiDi does not require any new spending on cables. Therefore, in comparison to QSFP SR4 transceivers, Cisco QSFP BiDi transceivers reduce costs by 100 percent and provide savings of up to US$290 per 40-Gbps port.

    Table 1.       Fiber Infrastructure Savings for 10-Gbps to 40-Gbps Direct-Cabling Migration and New 40-Gbps Deployment

    Fiber Cable Infrastructure Cost and Savings with BiDi* (US$)




    288 LC-connector dual-fiber MMF cables for Cisco BiDi




    288 MPO-connector ribbon-fiber MMF cables for SR4




    10-Gbps to 40-Gbps migration

    Total savings (US$)




    Per port savings (US$)




    Savings (percent)




    New 40-Gbps deployment

    Total savings (US$)




    Per-port savings (US$)




    Savings (percent)




    * This example is based on real-world cable cost estimates. The transceiver cost is not included.

    For the case in which 288 new direct 40-Gbps connections are needed in addition to the existing cabling infrastructure for a data center migration or expansion, the savings for 288 new connections using Cisco QSFP BiDi instead of QSFP SR4 transceivers is as high as 77 percent and US$221 per 40-Gbps port. These numbers do not take into account the installation costs. Adding installation costs could easily double the SR4 deployment costs.

    Case Study 2: 384 x 40-Gbps Connections with Structured Cabling

    A structured cabling system is commonly deployed in data center networks to provide flexible and scalable cabling infrastructure. Structured cabling uses short patch cords to attach devices to a patch panel and then runs fiber trunks either to consolidate the cables in a central location for additional connectivity or to direct them to another patch panel to which the remote devices are attached. Figure 5 shows a simple example of a 10-Gbps structured cabling design.

    Figure 5.      Simple Example of 10-Gbps Structured Cabling


    For migration of a data center with a structured 10-Gbps cabling system, Cisco QSFP BiDi technology allows you to repurpose the existing cabling system - including the patch cables, patch panels with MTP/MPO LC modules, and fiber trunks - for 40-Gbps connectivity. In contrast, QSFP SR4 transceivers require new patch cables and patch panels because the connector types differ and the size of the fiber trunk needs to be quadrupled.

    This case study examines a simple nonblocking two-tier fabric design (Figure 6) that provides 1536 10-Gbps edge ports on its leaf layer. Its spine layer is composed of two Cisco Nexus 9508 Switches, and its leaf layer consists of 32 Cisco Nexus 9396PX Switches, each with six 40-Gbps links to every spine Cisco Nexus 9508. There are 384 40-Gbps links total between the leaf and spine layers.

    Figure 6.      Two-Tier Network Example


    If 384 x 10-Gbps connections are to be reused to construct this network, no additional spending on cabling will be needed if Cisco QSFP BiDi transceivers are used for all the 40-Gbps links. This scenario thus offers a 100 percent cost savings compared to the cost of reconstructing the cabling system using QSFP SR4 transceivers, including the cost of new patch cables, new patch panels, and expansion of the current fiber trunk.

    If the cabling for this network is a new (greenfield) deployment or an expansion of an existing cabling system, the 384 x 40-Gbps connections can be built by using MMF cables and either QSFP SR4 transceivers or Cisco QSFP BiDi transceivers. Figures 7 and 8 show design examples for each option. Table 2 compares real-world cost estimates for these two designs. The design with Cisco QSFP BiDi offers 77 percent savings over that with QSFP SR4 transceivers, which is equivalent to a savings of US$2077 per 40-Gbps connection.

    Figure 7.      Structured 40-Gbps Cabling with QSFP SR4 Transceivers


    Table 2.       Structured 40-Gbps Cable Infrastructure Cost Comparison

    Structured 40-Gbps Cable Infrastructure Cost Savings with BiDi Technology (US$)


    Unit Price* (US$)


    Total (US$)

    90m 12-fiber MPO-MPO trunk cable (3 SR links per 2 cables)


    384 x (2/3)


    12-fiber MPO-MPO 2x3 conversion module (3 SR links per module, both ends)


    384 x (1/3) X 2


    12-fiber MPO jumper (1 per link, both ends)


    384 x 2


    SR total




    90m 12-fiber MPO-MPO trunk cable (6 BiDi links per cable)


    384 x (1/6)


    12-fiber MPO-LC trunk module (6 BiDi links per module, both ends)


    384 x (1/6)


    12-fiber LC jumper (1 per link, both ends)


    384 x 2


    BiDi total




    Total savings




    Percentage savings




    *Based on manufacturer’s list price
    Figure 8.      Structured 40-Gbps Cabling with Cisco QSFP BiDi Transceivers



    Cisco QSFP BiDi technology removes 40-Gbps cabling cost barriers for migration from 10-Gbps to 40-Gbps connectivity in data center networks. Cisco QSFP BiDi transceivers provide 40-Gbps connectivity with immense savings and simplicity compared to other 40-Gbps QSFP transceivers. The Cisco QSFP BiDi transceiver allows organizations to migrate the existing 10-Gbps cabling infrastructure to 40 Gbps at no cost and to expand the infrastructure with low capital investment. Together with Cisco Nexus 9000 Series Switches, which introduce attractive pricing for networking devices, Cisco QSFP BiDi technology provides a cost-effective solution for migration from 10-Gbps to 40-Gbps infrastructure.

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  • COMPUFOX SFP+ Direct Attach Copper Cables Solution

    SFP+ Direct Attach Copper Cable, also known as Twinax Cable, is an SFP+ cable assembly used in rack connections between servers and switches. It consists of a high speed copper cable and two SFP+ copper modules. The SFP+ copper modules allow hardware manufactures to achieve high port density, configurability and utilization at a very low cost and reduced power budget.

    Direct Attach Cable assemblies are a high speed, cost-effective alternative to fiber optic cables in 10Gb Ethernet, 8Gb Fibre Channel and InfiniBand applications. They are suitable for short distances, making them ideal for highly cost-effective networking connectivity within a rack and between adjacent racks. They enable hardware OEMs and data center operators to achieve high port density and configurability at a low cost and reduced power requirement.

    Compufox SFP+ copper cable assemblies meet the industry MSA for signal integrity performance. The cables are hot-removable and hot-insertable: You can remove and replace them without powering off the switch or disrupting switch functions. A cable comprises a low-voltage cable assembly that connects directly into two SFP+ ports, one at each end of the cable. The cables use high-performance integrated duplex serial data links for bidirectional communication and are designed for data rates of up to 10 Gbps.

    Types of SFP+ Direct Attach Copper Cables

    SFP+ Direct Attach Copper Cable assemblies generally have two types which are Passive and Active versions.

    SFP+ Passive Copper Cable
    SFP+ passive copper cable assemblies offer high-speed connectivity between active equipment with SFP+ ports. The passive assemblies are compatible with hubs, switches, routers, servers, and network interface cards (NICs) from leading electronics manufacturers like Cisco, Juniper, etc.
    SFP+ Active Copper Cable
    SFP+ active copper cable assemblies contain low power circuitry in the connector to boost the signal and are driven from the port without additional power requirements. The active version provides a low cost alternative to optical transceivers, and are generally used for end of row or middle of row data center architectures for interconnect distances of up to 15 meters.


    Applications of SFP+ Direct Attach Copper Cables

    -Networking – servers, routers and hubs
    -Enterprise storage
    -Telecommunication equipment
    -Network Interface Cards (NICs)
    -10Gb Ethernet and Gigabit Ethernet (IEEE802.3ae)
    -Fibre Channel over Ethernet: 1, 2, 4 and 8G
    -InfiniBand standard SDR (2.5Gbps), DDR (5Gbps), and QDR (10Gbps)
    -Serial data transmission
    -High capacity I/O in Storage Area Networks, Network Attached Storage, and Storage Servers
    -Switched fabric I/O such as ultra high bandwidth switches and routers
    -Data center cabling infrastructure
    -High density connections between networking equipment


    Compufox SFP+ Direct Attach Copper Cables Solution

    Compufox SFP+ twinax copper cables are avaliable with custom version and brand compatible version. All of them are 100% compatible with major brands like Cisco, HP, Juniper, Enterasys, Extreme, H3C and so on. If you want to order high quality compatible SFP+ cables and get worldwide delivery, we are your best choice.

    For instance, our compatible Cisco SFP+ Copper Twinax direct-attach cables are suitable for very short distances and offer a cost-effective way to connect within racks and across adjacent racks. We can provide both passive Twinax cables in lengths of 1, 3 and 5 meters, and active Twinax cables in lengths of 7 and 10 meters. (Tips: The lengths can be customized up to the customers' requirements.)

    -1m/3m/5m/7m/10m/12m available
    -RoHS Compatible
    -Enhanced EMI suppression
    -Low power consumption
    -Compatible to SFP+ MSA
    -Hot-pluggable SFP 20PIN footprint
    -Parallel pair cable
    -24AWG through 30AWG cable available
    -Data rates backward compatible to 1Gbps
    -Support serial multi-gigabit data rates up to 10Gbps
    -Support for 1x, 2x, 4x and 8x Fibre Channel data rates
    -Low cost alternative to fiber optic cable assemblies
    -Pull-to-release retractable pin latch
    -I/O Connector designed for high speed differential signal applications
    -Temperature Range: 0-70°C
    -Passive and Active assemblies available (Active Version: Low Power Consumption: < 0.5W Power Supply: +3.3V)


    FAQ of Compufox SFP+ Direct Attach Copper Cables

    Q: What are the performance requirements for the cable assembly?
    A: Our SFP+ copper passive and active cable assemblies meet the signal integrity requirements defined by the industry MSA SFF-8431. We can custom engineer cable assemblies to meet the requirements of a customer’s specific system architecture.

    Q: Are passive or active cable assemblies required?
    A: Passive cables have no signal amplification in the assembly and rely on host system Electronic Dispersion Compensation (EDC) for signal amplification/equalization. Active cable assemblies have signal amplification and equalization built into the assembly. Active cable assemblies are typically used in host systems that do not employ EDC. This solution can be a cost savings to the customer.

    Q: What wire gauge is required?
    A: We offer SFP+ cable assemblies in wire gauges to support customers' specific cable routing requirements. Smaller wire gauges results in reduced weight, improved airflow and a more flexible cable for ease of routing.

    Q: What cable lengths are required?
    A: Cable length and wire gauge are related to the performance characteristics of the cable assembly. Longer cable lengths require heavier wire gauge, while shorter cable lengths can utilize a smaller gauge cable.

    For all you SFP+ Direct attach cables, please see link below. We carry compatible cables for most major brands.


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  • How to Install or Remove SFP Transceiver Modules on Cisco Device

    The SFP (small form Factor pluggables) transceiver modules are hot-pluggable I/O devices that plug into module sockets. The transceiver connects the electrical circuitry of the module with the optical or copper network. SFP transceiver modules are the key components in today's transmission network. Thus, it is necessary to master the skill of installing or removing a transceiver modules to avoid unnecessary loss. This tutorial are going to guide you how to install or remove SFP transceiver module in a right way.


    Things you should Know Before Installing or Removing SFP

    Before removing or installing a Transceiver Module you must disconnect all cables, because of leaving these attached will damage the cables, connectors, and the optical interfaces. At the same time please be aware that do not often remove and install an SFP transceiver and it can shorten its useful life. For this reason transceivers should not be removed or inserted more often than is required. Furthermore, transceiver modules are sensitive to static, so always ensure that you use an ESD wrist strap or comparable grounding device during both installation and removal.


    Required Tools

    You will need these tools to install the SFP transceiver module:
    Wrist strap or other personal grounding device to prevent ESD occurrences.Antistatic mat or antistatic foam to set the transceiver on.Fiber-optic end-face cleaning tools and inspection equipment


    Installing SFP Transceiver Modules

    SFP transceiver modules can have three types of latching devices to secure an SFP transceiver in a port socket:
    SFP transceiver with a Mylar tab latch.SFP transceiver with an actuator button latch.SFP transceiver that has a bale-clasp latch.
    Types of SFP Latching

    Determine which type of latch your SFP transceiver uses before following the installation and removal procedures.

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  • Optics and Cables Selection for Storage Area Network (SAN)

    Optics and cables are the most important infrastructures of network connectivity. In a storage area network (SAN), switches are used between servers and storage devices. This means that you should make connection with optics and cables between the server and switch, storage and switch as well as the switch and switch. Of course, according to different application environments, you should choose different optics and cables in order to get the best performance. Furthermore, you may need to consider the future expansion of your network. Thus, an economical and effective solution of optics and cables are very necessary.

    Key Factors Influencing Your Decision

    Firstly, there are some key factors which will influence your decision. Thus, you must make sure that what your network really requires. As we mentioned above, an SAN has server, storage device and switches. So, what should we consider in every section of the network?

    1. Server
    Bandwidth: Depending on the application load requirements, customers typically decide whether they want 1GbE, 10GbE, or 40GbE. In some cases, the decision may also be dictated by the type of traffic, e.g. DCB (Data center bridging) requires 10GbE or higher.Cost: Servers claim the highest share of devices deployed in any data center. Choosing a lower cost connectivity option results in a much lower initial deployment cost.Power: In any high density server deployment, a connectivity option which consumes lower power results in much lower OpEx.Distance: Servers are typically connected to a switch over a very short distance, i.e. typically within the same rack or, in some cases, within the same row.Cabling Flexibility: Some customer prefer to make their own copper cables due to variable distance requirement. This requirement limits the choice of connectivity to copper cables only.


    2. Storage
    Reliability: Typical storage traffic is very sensitive to loss. Even a minor loss of traffic may result in major impact on application performance.Qualification: Storage vendor qualification or recommendation plays an important role in this decision due to reasons such as customer support, peace of mind, etc.Latency: Any time spent in transition is time taken away from data processing. Reducing transition time results in much faster application performance. The result may have a direct impact on customers' bottom line, e.g. faster processing of online orders.


    3. Switch
    Bandwidth: On server facing ports, servers typically dictate the per port bandwidth requirement. However, per port bandwidth requirement for the network facing (switch-to-switch) ports denpends on multiple factors including amount of traffic generated by the servers, oversubscription ratios, fiber limitations, ect.Distance: An inter-switch or switch to router connection could range from a few inches to tens of kilometers. Generally, the price of optics increases as the distance increases.Latency: The network topology and application traffic profile (East-west, HPC (High Performance Computing), computer cluster, etc.) and influence the minimun latency that can be tolerated in the network.


    • Server to Switch Connectivity Solution

    • Storage to Switch Connectivity Solution



    • Switch to Switch Connectivity Solution


     COMPUFOX Solutions

    COMPUFOX  offers a comprehensive solution of optics and cables which supports your network from 1GbE to 100GbE. We have a great selection of 1000BASE-T/SX/LX SFP, BiDi SFP, 10GBASE-SR/LR SFP+, DWDM SFP+, whole series 40G QSFP+ optics and cables, as well as the 100G CFP2 and CFP4, etc. which help you solve the cost issue in fiber project. Especially the 40G QSFP+ optics, with the passive optic design, they can be compatible with all the equipment of all major brands. In addition, most of them are ready stock. See Links below:

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