Category: Fiber Transceivers

Optical transceivers, Active Optic Cables, data center switches, and cable management in data centers.

WHICH FIBER PATCH CORD SHOULD BE USED FOR DIFFERENT TRANSEIVER TYPES?

Fiber Optic Networks have many features, ready to fulfill every customer’s needs for bandwidth, stability, reliability and most important cost-effective network architecture. There are many manufacturers that are offering their products on the market. Fortunately, most of their products are compatible between them, meaning we can mix and match different products from different manufacturers. However choosing the correct equipment for a specific network design is not a simple task. We must be really good prepared and we must know the properties of every single component of the fiber optic network in order to achieve a stable network architecture with possibility for future upgrades.

One of the key aspects to focus on when designing and deploying a fiber optic network is the connection between the main transmission components, the optical transceiver and the optical fiber cable. The fiber optic transceiver is a type of self-contained, hot swappable component that has the capability to convert electrical input into optical signal and vice versa, and with the help of lasers transmit these optical signals (optical light) down the optical cable. They are a key component for the fiber optic network and its performance. They are inserted in devices like servers, storages, switches and routers in a dedicated port on the device itself. There are many Form-Factors of transceivers with various properties, however the most commonly used are SFP+, QSFP and QSFP28 transceivers. The SFP+ transceivers are Small Form-Factor transceivers capable for speeds up to 16 GB/s and up to 80 kilometers, depending on the fiber type. The QSFP and QSFP28 transceivers are Quad Small Form-Factor transceivers capable for speeds up to 40 GB/s and 100 GB/s. QSFP has a range of up to 40 kilometers and QSFP28 has a range of up to 10 kilometers on Single-mode fibers.

When it comes to fiber optic cables, or fiber optic patch cords, they are composed of a fiber optic cable with a fiber optic connector ending on each end. According to the application they would be used for, they can be divided in several categories:

Multi-mode or Single-mode

Simplex or Duplex

According their connectors

When buying an optical cable we must know the distance they would be used for because this is the deciding factor when choosing Multi-mode of Single-mode fibers. Multi-mode fibers can come in four different modes, OM1, OM2, OM3 and OM4 and each of these four modes have different reach capabilities. However Multi-mode fibers are used for short reach because of their bigger core which transmits wider wavelength. Single-mode fibers are used for long reach distances because they transmit a narrower optical light via their smaller, around 9 micrometers, core. Simplex and duplex option explains the number of fiber cores consisted in a fiber optic cable. As the name suggests, simplex consists of one fiber core, while duplex consists of two fiber optic cores. According to their connectors there are many different types of cables. The most common used are cables with duplex LC connectors and the MPO/MTP trunk and breakout fiber optic cable solution. There are also cables with SC, ST, FC, E2000 and other connectors.

When choosing the correct patch cords it’s important to know the compatibility with the transceivers. Their compatibility could be found in their datasheets. When choosing cables with appropriate connectors we should keep in mind that the MPO/MTP connector solutions are the future of optical networking because they can support speeds up to 100 GB/s and they provide a solid ground for future network upgrades. Today for 40 GB/s a 12-fiber MPO/MTP connector is used because only 8 fibers are needed for successful connection, four used for transmitting, four used for receiving and four are left unused. For 100 GB/s solutions the use of 24-fiber MPO/MTP connectors is a must. These MPO/MTP connectors provide a seamless upgrade to 40 GB/s and 100 GB/s solutions. The MPO/MTP connectors are generally used with various QSFP type of transceivers, especially with QSFP28 because QSFP28 transceivers support bandwidth bigger than 40 GB/s, up to 100 GB/s.

The LC connector stands for Lucent Connector because it was firstly designed by Lucent Technologies. This connector has a body build similar to RJ jack style. These connectors are generally used in telecom rooms and network closets of a given organization. They are most commonly used for reach up to 10 kilometers on Single-mode fibers and with SFP+ transceivers.

Today many leading IT managers are searching for a cost-effective solution while not thinking about the future. Even though it’s more expensive to purchase, the MPO/MTP solution provides a seamless upgrade to new technologies and greater money savings on a long run. Also because of the way they are functioning they consume less space and make the whole maintenance process less complex.

WHAT KIND OF FIBER POLISH BE USED

When a connector is mounted on the fiber end, some loss of power will be experienced. Some of the light would be reflected back to the fiber towards the source that generated that light signal. These reflected back signals into the fiber are called Optical Return Loss (ORL). The ORL can harm the laser source can also interrupt the transmission signal. Usually the fiber connectors have different polishing types, the different polishing have different ORL levels. There are four polishing types available, each having its own ORL levels and characteristic. The polishing types are: 1. Flat surface, 2. Physical Contact (PC), 3. Ultra Physical Contact (UPC) and 4. Angled Physical Contact (APC). Each connector is evolved from one into another, let’s discuss each on detail.

Flat Fiber Connector

Originally the fiber connectors are flat surface connectors. A small gap between the two fiber faces is left when two faces of flat fibers are coupled. These flat fiber connectors are not appropriate for single mode fiber with a 9µm core size, therefore it is vital to advance into Physical Contact (PC) connectors. ORL values in this type of connectors is around -35dB.

Physical Contact (PC) Fiber Connector

Physical Contact connector is polished with a minor spherical design, this allow to decrease the general size of the end face. The spherical design helps to overcome the air gap issue experienced in flat connectors. The spherical design results in overall lower ORL, as a reduced amount of light being sent back into the fiber and also to the light source. ORL values in this type of connectors is around -45dB. But still some of the light manages to reflect back towards the source.

Ultra Physical Contact (UPC) Fiber Connector

To overcome the issue faced in physical contact connectors, the convex end face is made by extending the polishing methods on PC connectors, resulting an even finer connector that is called Ultra Physical Contact (UPC) connector. The UPC have even lower ORL as compare to PC connectors. ORL values in this type of connectors is upto -55dB. UPC fiber connector can be used with single-mode fiber as well as multimode fiber. Usually the blue color UPC connector is used for single-mode fiber and beige color UPC connector is used for multimode fiber. UPC allows more consistent signals in digital TV and telephony systems.

Previously discussed PC and UPC connectors have a low insertion loss, but ORL really depends on the surface finish of the fiber. When the connectors are repeatedly coupled and decoupled, the ORL will start to degrade. So it is essential for a connector with low back reflection and it could endure repeated coupling and decoupling without ORL degradation.

Angled Physical Contact (APC) Fiber Connector

The end faces of Angled Physical Contact (APC) connectors have curved edges but are angled at 8 degree of an industry standard. This allows even closer connection with a much smaller gap between two. The combination of angled connector with smaller gap, allows any reflected light that is reflected back into the fiber is in fact reflected into the fiber cladding. That is because of the 8 degree angled face. ORL values in this type of connectors is less then -65dB. This to be noted that these types of fiber connector can only be used with single-mode fiber. 

It’s vibrant from above discussion that all types of connectors play important role and are available in market. It seems difficult to conclude that which connector is best to use. The specific application requirement chooses which one to use. For application like high accuracy optical signals APC connectors may be selected, on other hand less complex systems will work fairly well using UPC or even FC connectors.

 WHAT IS SFP+ OR A SFP TRANSCEIVER

SFP stands for small form-factor pluggable it is a compact hot pluggable transceiver used for both telecom and the data applications. LC connectors are used to connect fibers to SFPs. SFP module has two sides, first side known as transmitter it has laser for transmitting and other side known as receiver side has a photo detector. So basically SFP is a transceiver module since it has transmitter and the receiver in a single unit.

SFPs are not standardized by any single body, but relatively are specified by a multi source agreement also called MSA. It is an agreement between several manufacturers to make products which are compatible among different vendors. SFP designed based on the bigger gigabit interface converter (GBIC) interface, but it has a much smaller size in order to increased port density, that is why SFP is also called mini- GBIC.

SFP modules are used in all types of network applications like data networks, telecommunication networks, SAN as well as SONED/SDH.

Typical SFP modules can be classified based on the working wavelengths and its working distance so let’s take a look at the list here:

For multimode fibers the SFP modules called SX (short reach) module, it use 850 nanometer wavelength. The distance that SX modules support depend on the network speed, for 1.25 gigabit per second speed the distance achieved is about 550 meters, whereas for 125 gigabit per second speed it supports up to 150 meters

For single mode fiber side there are lots of choices, following are the most common types:

For single-mode fibers the SFP modules called LX (long reach) module use 1310 nanometer wavelength laser and supports up to 10 kilometer. EX module use 1310 nanometer wavelength laser and supports up to 40 kilometer. ZX module use 1550 nanometer wavelength laser and supports up to 80 kilometer. EZX module use 1550 nanometer wavelength laser and supports up to 160 kilometer. CWDM and DWDM SFP transceivers are also used at different wavelengths for reaching several maximum distances. Also there are Gigabit Ethernet UTP copper cable modules available.

As mentioned earlier SFP module supports speed up to 4.25 gigabit per second and an enhanced version which is called SFP+ supports more than 10 gigabit per second and SFP+ is becoming more popular on 10 gigabit ethernet.

The enhanced small form-factor pluggable (SFP+) is an improved kind of the SFP that supports data rate up to 16 gigabit per second. SFP+ supports 8 gigabit per second Fibre Channel, 10 Gigabit Ethernet and Optical Transport Network standard OTU2.

10 gigabit per second or commonly called SFP+ modules, are precisely the same sizes as regular SFPs, permitting the equipment producer to re-use present physical designs for 24 and 48 port switches and modular line cards.

The advantages of using SFP or SFP+ is, these both transceivers are typically the size of an RJ-45 ethernet port. As compared to GBIC, XENPAK or XFP modules SFP and SFP+ uses small area and standardized size of connectors. SFP sockets are commonly found in Ethernet switches, routers, firewalls and Optical Line Terminal commonly called OLT.

Recent optical SFP transceivers also support Standard digital diagnostics monitoring (DDM). This feature is commonly known as digital optical monitoring (DOM). DOM capable SFP modules give end user the ability to observer parameters of the transceiver, such as transmitted optical power, received optical power, transceiver supply voltage, laser bias current, as well as temperature of SFP in real time. This feature is commonly applied for monitoring on switches, routers and optical equipment via SNMP.

Since these SFPs are specified by a multi source agreement, which permits compatibility among different vendors. So a single SFP purchased can be used from Cisco switch to Juniper Router and from HP server to Huawei OLT. Also SFP modules are hot pluggable, so unlike other network components/cards there is no need to power off the device when inserting the SFP.

Somethings you need to Know Before Selecting CWDM SFP Transceivers

As an extension of wavelength division multiplexing (WDM), coarse wavelength division multiplexing (CWDM) is a technology that multiplexes a number of optical carrier signals onto a single optical fiber through the use of different wavelengths (i.e., colors) of laser light.

A CWDM SFP (Small Form-factor Pluggable) transceiver is a hot-swappable input/output device that plugs into an SFP port or slot of a switch or router, linking the port with the fiber-optic network. It is a kind of optical-electric/electric-optical converter. With the transmitter on one end, the CWDM SFP transceiver takes in and converts the electrical signal into light, after the optical fiber transmission in the fiber cable plant, the receiver end again converts the light signal into electrical signal.

Being a kind of compact optical transceiver, CWDM SFP transceiver is widely used in optical communications for both telecommunication and data communication. It is designed for operations in Metro Access Rings and Point-to-Point networks using Synchronous Optical Network (SONET), SDH (Synchronous Digital Hierarchy), Gigabit Ethernet and Fiber Channel networking equipment.

Three Components of CWDM SFP Transceivers

The CWDM SFP transceiver consists of an un-cooled CWDM Distributed Feed Back (DFB) laser transmitter, a PIN photodiode integrated with a Trans-impedance Preamplifier (TIA) and a Microprogrammed Control Unit (MCU). The DFB laser used in the CWDM SFP transceiver transmitter is a 18 CWDM DFB wavelengths laser. It is well suited for high capacity reverse traffic. Obeying the standard diode equation for low frequency signals, The PIN photodiode has a 80km transmission distance. And the MCU is a high-speed, executive, input-output (I/O) processor and interrupt handler for the NRL Signal Processing Element (SPE).

Advantages of CWDM SFP Transceivers

Using existing fiber connections efficiently through the adoption of active wavelength multiplexing, CWDM SFP transceivers have improved the designs of telecommunications devices and other technologies. Here are some advantages of CWDM SFP transceivers:

1. Scalability and Flexibility

CWDM SFP transceivers can support multiple channels. It means that more channels can be activated as demand increases. CWDM SFP transceivers have a wide variety of network configurations that range from the meshed-ring configurations to the multi-channel point-to-point. In point-to-point configurations, the two endpoints will connect directly through a fiber link, allowing users to add or delete as many as eight channels at a time.

2. Low Risks in Investment

Most CDWM SFP transceivers have a low failure rate, which is less likely to be the reason why the user’s solution fails. It helps enterprises increase the bandwidth of the Gigabit Ethernet optical infrastructure without adding any additional fiber strands and can also be used in conjunction with other SFP devices on the same platform. Thus the user will be able to re-invest the capital saved by avoiding prematurely failed devices.

Selecting a Right CWDM SFP Transceiver

There are many kinds of CDWM SFP transceivers in the market. Their wavelengths are available from 1270 nm to 1610 nm, with each step 20 nm. Different CDWM SFP transceivers have different color codes, distances, data rates and laser operating wavelengths. For example, the CWDM-SFP-1470 transceiver, which is colored gray, is one of Cisco CWDM SFP. It is a CWDM SFP transceiver that rates for distances up to 80 km and a maximum bandwidth of less tan 1.5 Gbps, operating at 1470nm wavelength.

CWDM-SFP-1490 transceiver, however, is designed for single mode fiber and operates at a nominal wavelength of CWDM wavelength. Colored purple, it rates for distances up to 80 km and a maximum bandwidth of 1.5 Gbps, operating at 1490 nm wavelength. Cisco CWDM-SFP-1470Cisco CWDM-SFP-1490 Customers may choose a CWDM SFP transceiver in accordance with their actual needs. Applied to the access layer of Metropolitan Area Network (MAN), The CWDM SFP is a low-cost WDM transmission technology.

fiber-mart.com provides the aforesaid CWDM-SFP-1470, CWDM-SFP-1490 and other types of CDWM SFP Transceivers, which are convenient and cost-effective solution for the adoption of Gigabit Ethernet and Fiber Channel (FC) in campus, data center, and metropolitan-area access networks.

Compatible Juniper QSFP+ LX4 Transceiver Introduction

In today’s data center communications, individual streams routinely reach 10 Gbps speeds, and it is necessary to have 40GbE links to provide better performance. Such high-performance, high-density 40 Gbps network devices such as Juniper Networks switches, when equipped with LX4 optics, seamlessly enable this transition. This article introduces Juniper QSFP+ LX4 transceiver in details.

The Rise of 40 Gbps QSFP+ LX4 Technology

Short-reach (SR) and extended short reach (eSR4) transceivers for 40 Gbps connectivity in a quad small form-factor pluggable transceiver (QSFP) mode use independent transmit and receive sections, each with four parallel fiber strands. For a duplex 40 Gbps connection, eight fiber strands are required, while QSFP SR4 uses Multipath Optical (MPO) 12-fiber connectors (MPO-12F). This IEEE standard technology must reach up to 400m using OM4 and provide future support for 100 Gbps speeds using the same cabling infrastructure. However, this technology requires more fiber strands than can be found in today’s 10 Gbps infrastructures, which means that data centers require a cabling upgrade. Juniper offers an innovative alternative: a 40 Gbps QSFP plus (QSFP+) LX4 technology that allows for zero-cost fiber migration by reusing the current 10 Gbps multi-mode fiber optic (MMF) cabling plant for 40 Gbps connectivity.

Introduction to Juniper 40 Gbps QSFP+ LX4

Juniper offers a new 40 Gbps Ethernet optical technology called LX4 and provides a QSFP+ 40GbE optical module that uses the same infrastructure as 10GbE. The LX4 technology represents a new way to deploy 40GbE that meets all of the performance criteria of today’s data centers by providing 40GbE on two MMF strands and duplex LC connectors. The Juniper QSFP+ LX4 transceiver addresses the challenges of fiber infrastructure by providing the ability to transmit full-duplex 40 Gbps traffic over one duplex MMF cable with LC connectors. In other words, the Juniper QSFP+ LX4 transceiver, a short-reach optical transceiver that delivers 40 Gbps over duplex OM3 or OM4 MMF, allows 40 Gbps connectivity to connect directly to the 10 Gbps fiber and fiber trunk.

The Juniper QSFP+ LX4 transceiver has four 10 Gbps channels, each of which can transmit and receive simultaneously on four wavelengths over a MMF strand. The result is an aggregated duplex 40 Gbps link over a duplex of two MMF strands. Using duplex LC connectors, QSFP+ LX4 connections can reach 100 meters on OM3 MMF or 150 meters on OM4 MMF.

About fiber-mart.com’s 40G QSFP+ LX4 Transceivers

As a professional manufacturer and supplier for optical fiber products as well as third-party, fiber-mart.com’s 40G QSFP+ LX4 transceivers support highly reliable operations in data center networks, and are optimized for various switching platforms by offering the perfect compatibility with brands, such as Juniper. The fiber-mart.com compatible Juniper 40G QSFP+ LX4 transceiver can save you a lot of budget and provides the same functions just as Juniper 40G QSFP+ LX4 transceiver. And there is no need to worry about the quality or performance of 40G QSFP+ LX4 transceiver offered by fiber-mart.com.

Features of fiber-mart.com’s compatible Juniper 40G QSFP+ LX4 Transceivers:

QSFP+ MSA compliant

EEE 802.3ba Electrical Interface

LC duplex connector

Up to 150m over duplex OM3 or OM4 fiber, 500m over duplex single-mode fiber

Compliance with Restriction on Hazardous Substances (RoHS) directive

Conclusion

All fiber-mart.com’s 40G QSFP+ LX4 transceivers, including the compatible ones mentioned above, provide high density and ensure high quality. Besides, fiber-mart.com’s compatible Juniper 10G SFP/XFP transceivers and 1000G SFP transceivers, like EX-SFP-10GE-LR, XFP-10G-E-OC192-IR2, JX-SFP-1000BASE-T are also available. For more information about fiber-mart.com 100% compatible transceivers with Juniper, please visit fiber-mart.com.

The Way to Choose Suitable Patch Cable for Optical Transceiver?

People are always amazed by the fast development of optical communication. Fiber optic transceiver, a small-size but important component, can best represent the advancing of the optical communication industry. The form factor of optical transceiver has changed from GBIC for Gigabit Ethernet to SFP+ for 10GbE, QSFP+ for 40GbE and CFP or QSFP28 for 100GbE. It is not difficult to tell the differences among these transceivers. However, users may feel confused about the patch cable which is used to connect optical transceiver to the telecommunication network. This post will introduce how to choose the suitable patch cable for optical transceiver from the aspects of transmission media, transmission distance & rate, and interface.

Optical Transceiver and Patch Cable Overview

Optical transceiver or optical transmitter and receiver (shown in the following picture) is a device that uses fiber optics technology to send and receive data. The transceiver has electronic components to condition and encode/decode data into light pulses and then send them to the other end as electrical signals. To send data as light, it makes use of a light source, which is controlled by the electronic parts, and to receive light pulses, it makes use of a photodiode semiconductor. There are different types of transceivers for different Ethernet networks, such as 1G GBIC, 10G SFP+, 40G QSFP+, etc.

A patch cable or patch cord is an electrical or optical cable used to connect one electronic or optical device to another for signal routing. It is composed of electrical or optical cable terminated with connectors at each end. Optical patch cable is the most popular cable widely applied in data center and telecommunication networks. They can be differ from different connector types (see in the image below), like LC, SC, ST and FC, etc, different core diameters, like single-mode optical patch cable, multimode optical patch cable, and different fiber cable structure, like simplex optical patch cable and duplex optical patch cable.

Factors to Consider When Choosing patch cable for Optical Transceiver

Transmission Media

As we all know, there are two kinds of transmission medias in the network—fiber optic and copper. Therefore, based on these two media types, transceivers can be divided into fiber optic based transceiver and copper based transceiver. Copper based transceiver, such as 1000Base-T SFP and 10GBase-SFP+, which usually has a RJ45 interface, can achieve connection to the network with the use of cat5/6/7 patch cables.

Compared to copper based transceiver, patch cable choices for fiber optic based cable are more complicated. Generally, fiber optic patch cable comes in two types: single-mode fiber patch cable and multimode fiber patch cable, and each type can be used in different applications. Single-mode fiber patch cable can be further classified into OS1 and OS2, while multimode fiber patch cable can be further divided into OM1. OM2, OM3 and OM4. Single-mode fiber optic cable has a small diameter core that allows only one mode of light to propagate, so it is suitable for long distances data transmission. On the contrary, multimode fiber optic cable has a large diameter core that allows multiple modes of light to propagate, thus it is available for short distance data transmission. Typically, if the transmission distance is shorter than 500 meters, multimode fiber optic cable is suggested, otherwise, the single-mode fiber patch cable is a better choice.

Transmission Distance and Rate

It is known that the transmission rate will decrease as the transmission distance increases. Single-mode fiber patch cable can provide higher performance for different rates in both short and long distances, but it will cost more. When it comes to short transmission distance, it’s better to choose multimode fiber patch cable. As we have mentioned above, multimode fiber patch cable can be classified into OM1, OM2, OM3 and OM4.

OM1 patch cable supports 10 Gigabit Ethernet applications at 33 m, but is usually used for 100 Megabit Ethernet applications, while OM2 patch cable is standardized to support 10 Gigabit Ethernet applications at 82 m, but is usually applied for 1 Gigabit Ethernet applications. OM3 patch cable is commonly used to run 10 Gigabit Ethernet applications at 300 m, though it has been improved to work with 40G and 100G Ethernet applications if using a MPO connector. OM4 patch cable is optimized to support 10 Gigabit Ethernet at length up to 550 m, and 100 Gigabit Ethernet at 150 m with MPO connectors. The different performances of multimode fiber patch cable types are shown in the table below.

Transceiver Interface

Transceiver interface is also an important factor when selecting patch cable for transceiver. Most optical transceivers have two ports, one port for transmitting and one port for receiving, so duplex SC and LC interfaces are usually employed. However, for BiDi transceiver which has only one port for both transmitting and receiving, simplex fiber patch cords will be used. For 40G QSFP+ transceivers, which often use MPO/MTP interfaces, multimode fiber patch cords attached with MPO/MTP connectors will be deployed.

Conclusion

Optical transceiver and patch cable are both vital components in telecommunication networks. Without any of these two devices, the network connection can be achieved. Only matched optical transceivers and patch cables can provide better performance. Through the information that we have mentioned above, hope you can choose the suitable patch cable for your optical transceiver.