Category: Fiber Transceivers

While installing fiber optic cables, you will come across such questions. Should I choose to field terminate fiber optic cables or just turn to pre-terminated fiber optic cables? Which choice is better for the installation? Before jumping to a decision, you need to take a few things into consideration. In this article, we will discuss what cable construction type you need and understand why a pre-terminated fiber option is a better choice for you.

What May Pre-Terminated Fiber Cables Bring to You?

Pre-terminated cabling systems have been in use for a number of years. Nowadays they have been regarded as the “norm” for Data Center applications. There are reasons for it.

Time saving: Without doubt, pre-terminated fiber cables can help you save a lot of time. As the products are terminated in a factory environment and delivered to site, minimal engineering or assembly work is required on site. Pre-terminated solutions also save testing time. The pre-terminated solutions can be tested at the factory and transported to site, which minimises the occurrence of faulty connections.

Space Saving: Pre-terminated fiber cable is much higher in density. And, installers need space to store the components and work areas to make terminations. Using a pre-terminated solution can be space saving as the pre-terminated links are “made to measure” and they don’t need to be stored when delivered as needed and can be put to use immediately.

Pre-terminated cables or fiber optic patch cables assemblies eliminate time-consuming field-termination processes and provide a factory-tested and certified endface. But they also have disadvantages. Prepolished connectorized fibers can cost much more than epoxy-style field-polish connectors. And cable length needs to be precisely measured. If pre-terminated cables are too short, you will have to install a replacement; if they are too long, you will have to deal with installation issues associated with managing the extra cable length, which will also cause additional expense.

What May Field Termination Bring to You?

As you know, optical fiber, mainly made of glass, is very fragile and difficult to install. Termination of installing optical fiber cables has always been perceived as a difficult, expensive, and time-consuming process, whether the termination is done in the field or it is an in-house operation, which discourags a lot of installers. And now, with the development of new high speed systems, termination is becoming more and more difficult. For example, multi-mode fiber networks for 40Gbit/s and 100Gbit/s applications use parallel transmission with 8 or 20 fibers per link utilizing 12-fiber MTP/MPO connectors, making it harder to terminate than a single fiber connector. Instead, a pre-terminated MPO cable would be much easier. Why not choose to field terminate fiber optic cabling systems? Here are several troubles that a field termination may bring to you.

Polishing process: Polishing the fiber is one of the most critical step in the connectorization process. Polishing is the process of creating a smooth surface by rubbing it or using a chemical action, leaving a surface with a significant specular reflection. Polishing finalizes the connector endface and cleans the surface, which has a direct impact on such optical performance parameters as insertion loss, return loss, and bit-error-rate for overall network performance. Reliable polishing processes rely on proper training and a well-equipped termination toolkit. Many installers fear connectorizing optical fiber cable, mainly due to the delicate techniques of polishing.

Connector protection: Another problem is how to protect the connectors. We know that optical fiber connector is a high-precision device with tolerances on the order of microns, it is crucial that the fiber should not only be formed perfectly to align with a mating connector, but that it should be free of any dust or dirt. Failing to do so can cause high insertion loss and high reflection, and can contaminate the equipment to which the connectors and patch cords will be connected. In a field termination process, extra attention must be paid to the handling of the collectors. Bad environment may increase the possibility of a connector failure.

Cost: Besides, fiber termination involves a heavy investment into the proper tools and test equipment to make a proper fiber connection at the location. For example, you need a cable stripper to remove the tight buffer, a ruler and a marker to measure the length and mark on the fiber jacket, and some fiber optic cleaning fluid to clean the bare fiber, and so on. The most costly part of field termination kit is going to be your cleaver. Some only cleave multimode fibers and some do both multimode and singlemode fibers. So if you decide to field terminate fiber optic cables, you must prepare all those termination tools that you need, which is a big load for field termination.

How Do You Make A Choice?

Pre-terminated fiber cable is relatively a much easier way to install fiber cable. The connectors you specify are pre-terminated for you, and the fiber cable you specify is cut to the proper length that you need. When the installation is over, you can just plug and play fiber optic system. It is perfect for beginners and also convenient for professional fiber optic installers. Many cable and patchcord manufacturers offer a cable termination service. If you have a good cable plant layout design and can accurately calculate cable lengths between termination points, all you have to do is specify what kind and number of fibers, the fiber types and connector types and the cable length that you need. Then the manufacturer would supply a completed assembly, and the cable is terminated with connectors, fully tested and fitted with protective sleeving at each end. Pre-terminated fiber cable is an excellent choice.

Conclusion

Pre-terminated fiber cables do offer a number of advantages for a variety of different network installations for reasons of time saving and space saving. However, it doesn’t mean that you can get all the benefits offered by a pre-terminated solution. A large amount of planning needs to be carried out prior to installation. Attention to details in the site survey process is critical, or these benefits will be lost and additional cost incurred. A pre-terminated solution is a pre-planned solution. Only when you preplan it well can it work well.

In communication networks, many transmission lines need bidirectional transmission. This need leads to the development of Bidirectional (BiDi) transceivers, which can transmit and receive data to/from interconnected equipment through a single optical fiber. BiDi transceivers are fitted with wavelength division multiplexing (WDM) diplexers, which combine and separate data transmitted over a single fiber based on the wavelengths of the light. BiDi transceivers must be deployed in matched pairs, with their diplexers tuned to match the expected wavelength of the transmitter and receiver that they will be transmitting data from or to. In this post, a kind of BiDi transceiver, 1000BASE-BX SFP BiDi transceiver will be introduced.

Introduction

1000BASE-BX is a part of the Gigabit Ethernet standard related to transmission over fiber optic cable. 1000BASE-BX SFP modules are compliant with SFP Multi-Source Agreement (MSA) specification and SFF-8472, and conform to the IEEE 802.3ah 1000BASE-BX10 standard. 1000BASE-BX SFP modules include 1000BASE-BX-U SFP module and 1000BASE-BX-D SFP module. These two SFP modules must be used in pairs to permit a bidirectional Gigabit Ethernet connection using a single strand of single mode fiber (SMF) cable. These transceivers transmit and receive signals on one fiber strand using two wavelengths in each direction. These hot pluggable optical transceivers consist of two sections: the transmitter section uses 1490nm DFB laser/1310nm Fabry-Perot laser, and the receiver section uses 1310nm/1490nm receiver accordingly. The 1000BASE-BX-D SFP operates at wavelengths of 1490nm TX/1310nm RX, and the 1000BASE-BX-U SFP operates at wavelengths of 1310nm TX/1490nm RX. These transceivers use standard simplex LC connectors for fiber cable connection and provide a long transmission distance of up to 10 km.

Key Features

Data rate up to 1.25 Gbps

Hot-pluggable SFP footprint

1490 nm DFB Transmitter and 1310 nm PIN Receiver

1310 nm FP Transmitter and 1490 nm PIN Receiver

Transmission distance up to 10 km

Simplex LC connector

Low power dissipation

Digital diagnostic monitor interface is compliant with SFF-8472

Compliant with SFP MSA Specification

Compliant with IEEE 802.3z Gigabit Standard

RoHS compliance

1000BASE-BX-D SFP

1000BASE-BX-D SFP supports link length of up to 10km point to point on single mode fiber (1490nm-TX/1310nm-RX wavelength) at 1Gbps bidirectional. This optic uses an LC connector. The picture below show a Cisco GLC-BX-D compatible 1000BASE-BX-D SFP 1490nm-TX/1310nm-RX transceiver. The GLC-BX-D is a small form factor pluggable module for Gigabit Ethernet 1000BASE-BX and Fiber Channel communications. The GLC-BX-D transceiver operates at 1490Tx/1310Rx wavelength. It is compatible with the IEEE 802.3ah 1000BASE-BX10-D standards. A 1000BASE-BX-D device is always connected to a 1000BASE-BX-U device with a single strand of standard SMF.

1000BASE-BX-U SFP

1000BASE-BX-U SFP supports link length of up to 10km point to point on single mode fiber (1310nm-TX/1490nm-RX wavelength) at 1Gbps bidirectional. This optic uses an LC connector. The communication over a single strand of fiber is achieved by separating the transmission wavelength of the two devices. 1000BASE-BX-D transmits a 1490nm channel and receives a 1310nm signal, whereas 1000BASE-BX-U transmits at a 1310nm wavelength and receives a 1490nm signal. A wavelength-division multiplexing (WDM) splitter integrated into the SFP to split the 1310nm and 1490nm light paths. The GLC-BX-D and GLC-BX-U SFPs also support digital optical monitoring (DOM) functions according to the industry-standard SFF-8472 multisource agreement (MSA). This feature gives the end user the ability to monitor real-time parameters of the SFP, such as optical output power, optical input power, temperature and transceiver supply voltage. The picture below show a Cisco GLC-BX-U compatible 1000BASE-BX-U SFP 1310nm-TX/1490nm-RX transceiver.

Applications

Gigabit Ethernet

Fiber Channel Links

Switch to switch interface

Switched backplane applications

Pouter/Server Interface

Other optical transmission systems

Conclusion

New organizational applications, virtualization, and data center consolidation trends are pushing your server I/O requirements to meet higher needs than before. With new BiDi optical technology, SFP BiDi transceivers make it much easier for you to upgrade your networks.

40GBASE QSFP+ (quad small form factor pluggable) portfolio offers customers a wide variety of high-density and low-power 40 Gigabit Ethernet connectivity options for data center, high-performance computing networks, enterprise core and distribution layers, etc. And each kind of 40GBASE QSFP+ transceiver has its special applications. 40GBASE-LR4 QSFP+ transceiver is a common 40 Gigabit Ethernet connectivity option. Here is some basic information about 40GBASE-LR4 QSFP+ transceiver.

Introduction

40GBASE-LR4 QSFP+ module supports link lengths of up to 10 kilometers over a standard pair of G.652 single-mode fiber with duplex LC connectors. The 40 Gigabit Ethernet signal is carried over four wavelengths. Multiplexing and demultiplexing of the four wavelengths are managed within the device. The letter “L” stands for long, the “R” denotes the type of interface with 64B/66B encoding and the numeral 4 indicates numeral 4 indicates that the transmission is carried out over a ribbon fiber with four singlemode fibers in every direction. Each lane has a 10 Gbit/s data rate. 40GBASE-LR4 QSFP+ transceiver modules are compliant with the QSFP+ MSA and IEEE 802.3ba 40GBASE-LR4. The picture below shows a Mellanox MC2210511-LR4 compatible 40GBASE-LR4 QSFP+ transceiver.

Two Types of 40GBASE-LR4 QSFP+ Transceiver

There are mainly two of 40GBASE-LR4 QSFP+ transceivers, 40GBASE-LR4 CWDM (coarse wavelength division multiplexing) QSFP+ transceiver and 40GBASE-LR4 PSM (parallel single-mode fiber) QSFP+ transceiver. This part mainly talks about these two 40GBASE-LR4 QSFP+ transceiver types.

40GBASE-LR4 CWDM QSFP+ transceiver, such as QSFP-40GE-LR4, contains a duplex LC connector for the optical interface. It can support transmission distance of up to 10km. A 40GBASE-LR4 CWDM QSFP+ transceiver converts 4 inputs channels of 10G electrical data to 4 CWDM optical signals by a driven 4-wavelength distributed feedback (DFB) laser array, and multiplexes them into a single channel for 40G optical transmission. Then the receiver module accepts the 40G CWDM optical signals input, and demultiplexes it into 4 individual 10G channels with different wavelengths.

40GBASE-LR4 PSM QSFP+ transceiver is a parallel single-mode optical transceiver with an MTP/MPO fiber ribbon connector. It also offers 4 independent transmit and receive channels, each capable of 10G operation for an aggregate data rate of 40G. The transmitter module accepts electrical input signals compatible with common mode logic (CML) levels. All input data signals are differential and internally terminated. The receiver module converts parallel optical input signals via a photo detector array into parallel electrical output signals. The receiver module outputs electrical signals are also voltage compatible with CML levels.

Applications

QSFP-40GE-LR4 supports 40GBASE Ethernet rate only, whereas the QSFP-40G-LR4 supports OTU3 data rate in addition to 40GBASE Ethernet rate. 40GBASE-LR4 QSFP+ transceivers are most commonly deployed between data-center or IXP sites with single mode fiber.

fiber-mart.com offers customers a wide variety of 40GBASE-LR4 QSFP+ transceivers for your high-density and low-power 40 Gigabit Ethernet connectivity options, including 40GBASE-LR4 CWDM QSFP+ transceiver and 40GBASE-LR4 PSM QSFP+ transceiver, like Cisco QSFP-40GE-LR4 40GBASE-LR4 QSFP+ transceiver. fiber-mart.com also provides wide brand compatible 40G QSFP+ transceivers, such as Brocade QSFP+, Dell QSFP+, Juniper QSFP+, Mellanox QSFP+, and HP QSFP+. Each fiber optic transceiver provided by fiber-mart.com has been tested to ensure its compatibility and interoperability.

The number of network connections in data centers is on the rise. Data centers have to achieve ultra-high density in cabling. Multimode fiber optics is the medium of the future for satisfying the growing need for transmission speed and data volume over short distances. Parallel optics technology is what you get if you combine both trends—cabling density and the use of fiber optics. It is a suitable solution for high-performance data networks in data centers. This passage provides introductory information on parallel optics technology.

What Is Parallel Optics?

Parallel optics is a term used to represent both a type of optical communication and the devices on either end of the link that transmit and receive information. It differs from traditional fiber optic communication in that data is simultaneously transmitted and received over multiple optical fibers. In parallel optical communication, the devices on either end of the link contain multiple transmitters and receivers. For example, four transmitters on End A communicate with four receivers on End B, spreading a single stream of data over four optical fibers. With this configuration, a parallel optics transceiver can use four 2.5Gb/s transmitters to send one 10Gb/s signal from A to B.

Parallel optical devices are fundamentally different in construction from serial optical devices. Two complementary technologies have enabled the development and deployment of parallel optics devices: vertical cavity surface emission lasers (VCSELs) and the MPO connector. Parallel optic transmission technology spatially multiplexes or divides a high-data-rate signal among several fibers that are simultaneously transmitted and received. At the receiver, the signals are de-multiplexed to the original high-data-rate signal. MPO connectivity is used throughout the parallel optic link and interfaces into the transceiver module. An MPO connector and its connectivity method is showed in the picture below (Tx stands for transmit, Rx stands for receive).

Applications of Parallel Optics Technology

Parallel optic interfaces (POIs) are a fiber optic technology primarily targeted for short-reach multimode fiber systems (less than 300 meters) that operate at high data rates. Duplex fiber serial transmission with a directly modulated 850 nm VCSEL has been used to date for data rates up to 10G. Current and future protocols expected to use parallel optics include 40G and 100G Ethernet, InfiniBand and Fibre Channel speeds of 32G and higher. IEEE has already included physical layer specifications and management parameters for 40Gbps and 100Gbps operation over fiber optic cable. The uses of parallel optics technology continues to evolve and takes shape as higher-speed fiber optic transmission. Many cabling and network experts have pointed out that parallel optical communication supported with MPO technology is currently a way to equip an environment well prepared for the 40/100GbE transmission.

Why Choose Parallel Optics?

Parallel optical communication uses multiple paths to transmit a signal at a greater data rate than the individual electronics can support. Parallel transmission can either lower the cost of a given data rate (by using slower, less expensive optoelectronics) or enable data rates that are unattainable with traditional serial transmission. Moreover, POIs offer an economical solution that utilizes multimode fiber, which is optimized with VSCEL sources. This means that for speeds faster then 16G, parallel optics, is the most practical, cost-effective solution.

Parallel optics is one technology currently on the market for high data rates networking solutions. Fiberstore is a professional manufacturer and supplier, which offers a large amount of cables and transceivers for your parallel optics applications, such as QSFP+ transceiver and QSFP+ cable. Parallel optical transceivers used for 40GBASE-SR4 and 40GBASE-CSR4 have 10-Gbps electrical lanes that are mirrored in the optical outputs.

In recent years, 40 Gigabit Ethernet (GbE) has gained more popularity and the market of 40GbE is encouraging. But with the rapid growth of the new standard 100GbE, a new voice is announcing, namely 25GbE. As the increasing bandwidth requirements of private and public cloud data centers and communication service providers, 25GbE will to have a significant impact on server interconnect interfaces. Now you have two upgrade paths to 100G, 10G-25G-100G and 10G-40G-100G. Which one to choose? This post will make a comparison of 25GbE and 40GbE cabling, hoping it can help you make an appropriate decision.

25GbE Cabling Overview

25GbE is a standard developed by developed by IEEE 802.3 task forces P802.3by, used for Ethernet servers and switches connectivity in a datacenter environment. The single-lane design of 25 GbE gives it a low cost per bit, which enables cloud providers and large-scale data center operators to deploy fewer switches to meet the needs while still scaling their network infrastructure.

25GbE physical interface specification supports two main form factors, SFP28 (1×25 Gbps) and QSFP28 (4×25 Gbps). 25GBASE-SR SFP28 is an 850nm VCSEL 25GbE transceiver available in the market. It is designed to transmit and receive optical data over 50/125µm multi-mode optical fiber (MMF) and support up to 70m on OM3 MMF and 100m on OM4 MMF (LC duplex). In fact, using an SFP28 direct attach copper (DAC) cable for switches direct connection is a preferred option now. In addition, a more cost-effective solution is to use a QSFP28 to 4xSFP28 breakout cable to connect a 100GbE QSFP28 switch port with four SFP28 ports. DAC cable lengths are limited to three meters for 25GbE. Thus, active optic cable (AOC) solutions are also used for longer lengths of applications.

40GbE Cabling Overview

40GbE is a standard developed by the IEEE 802.3ba task force. The official development of 40GbE standards first began in January 2008, and were officially approved in June 2010. At the heart of the 40GbE network layer is a pair of transceivers connected by a fiber optic cable, OM4 or OM3 fiber cable. Fiber optic transceivers are plugged into either network servers or a variety of components, including interface cards and switches.

There are several standard form factors of 40GbE transceivers in the whole evolution. The CFP (C form-factor pluggable) transceiver uses 12 Tx and 12 Rx 10Gbps lanes to support one 100GbE port, or up to three 40GbE ports. With its large size, it can meet the needs of single-mode optics and can easily serve multi-mode optics or copper. But it is gradually falling behind since the increasing demand for high density. Another form factor is the CXP. It also provides twelve 10Gbps lanes in each direction, but is much smaller than the CFP and serves the needs of multi-mode optics and copper. At present, the most commonly used 40GbE form factor is the QSFP+ (quad small form-factor pluggable plus). It has the similar size with CXP but can provide four Tx and four Rx lanes to support 40GbE applications for single-mode, multi-mode fiber and copper.

Fiber optic cabling and copper cabling are both available for 40 GbE. The supportable channel length depends on the cable and the transceiver type. For data center 40GbE fiber optic cabling, OM3 and OM4 multi-mode cables are generally recommended because they can support a wider range of deployment configurations compared to copper solutions, and lower costs compared to single-mode solutions. MPO/MTP connectors are used at the multimode transceivers to support the multifiber parallel optics channels. For copper solutions, you can use QSFP+ direct attach copper cables, such as Cisco QSFP+ breakout cable. There are a lot of options, both active and passive, like Cisco QSFP-4SFP10G-CU5M compatible 40G QSFP+ to 4x10G SFP+ passive direct attach copper breakout cable (as shown below).

25GbE Cabling vs 40GbE Cabling

Compared to 40 GbE, 25GbE seems to be more suitable and cost-effective for cloud and web-scale data center applications. Using 25GbE with QSFP28 transceivers, users can deliver a single-lane connection, similar to the existing 10GbE technology but with 2.5X faster performance. In addition, 25GbE can provide superior switch port density by requiring just one lane (vs. 4 lanes with 40 GbE). Thus, it costs less and requires lower power consumption. Benefits of 25GbE compared to 40GbE are shown as below:

Greater port density vs 40 GbE (one lane vs. four lanes)

Maximum switch I/O performance and fabric capability

Lower cost versus 40 GbE

Reduced capital expenditures (CAPEX) and operational expenditures (OPEX)

Fewer ToR switches and fewer cables

Requires less power, cooling, and footprint

Leverage of the existing IEEE 100GbE standard

Summary

25GbE seems to be a preferred option in the next step. It can provide up to 2.5 times faster performance than the existing 10GbE connections while maximizing the Ethernet controller bandwidth/pin and switch fabric capability. It can also provide greater port density with lower cost compared to 40GbE solutions. The trend will always be wider band and higher speed and port density. 25GbE or 40 GbE, let’s wait and see how things play out.

Over the years of SFP transceiver communication existence, there have been numerous different standards introduced. The great thing about SFP transceivers in networking hardware is that they allow a single piece of equipment, such as a switch, to support different wiring and transmission formats. The problem comes when trying to figure out which of the many transceiver types out there you need. There are several different types of SFP transceivers capable of supporting a multitude of communication standards, such as: CWDM/DWDM, SONET, Fibre Channel, Fast Ethernet and Gigabit Ethernet.

CWDM/DWDM SFP Transceivers

WDM, or wavelength-division multiplexing, is a type of technology that allows a transceiver to have different wavelengths assigned to it.Coarse wavelength-division multiplexing (CWDM) SFP transceivers are capable of transmitting data at eight different wavelengths ranging from 1470nm to 1610nm. CDWM SFP transceivers are color coded, to help identify which wavelength is mapped to the transceiver.Dense wavelength-division multiplexing (DWDM) SFP transceivers are available in 32 different wavelengths, and offer high-capacity bandwidth for serial optical data communications. DWDM SFP transceivers are slightly more expensive than CWDM SFP transceivers, but the more densely spaced channels allow for a greater number of wavelengths to travel over a single fiber.Both CWDM and DWDM SFP transceivers can be used to transmit data over Gigabit Ethernet, SONET and Fibre Channel.

SONET SFP Transceivers

Synchronous optical networking (SONET) technology enables the transmission of a large volume of data over long distances. SONET can be used to transmit multiple streams of data simultaneously over fiber optic mediums using laser beams and LEDs.SFP transceivers are built to transmit data over SONET at varying rates (OC-3, OC-12 and OC-48) and with different reaches (short-reach, intermediate-reach, and long-reach). SONET SFP transceivers are able to transmit data over both singlemode and multimode fiber.

Fibre Channel SFP Transceivers

Fibre Channel is a protocol which is used primarily in “Storage Area Networks”. It comes in different speeds like 1xFC, 2xFC, 4xFC, 8xFC and 16xFC. Fibre Channel was developed as a lossless protocol in a time when switches were less reliable than they are today. When using Ethernet as a protocol, frames were dropped, which created a problem for applications like data traffic. With the advent of greater technology, switches are now much more reliable; however, Fibre Channel still holds a small advantage over Ethernet when it comes to consistency and latency.Fibre Channel SFP transceivers are modules commonly used in storage area networks (SAN) and are available in 1, 2, 4, 8, 10, 16 and 20Gbps data transmission rates. Fibre Channel SFP transceivers can be used in both singlemode and multimode fiber applications.

Fast Ethernet and Gigabit Ethernet

Fast Ethernet is slowly being replaced with Gigabit Ethernet. Fast Ethernet SFP transceivers were originally designed to transmit data at 10Mbps, and eventually reached transmission speeds of 100Mbps (100Base). 100Base rate Fast Ethernet transceivers are available in the following interface types: FX, SX, BX and LX10.With the development of Gigabit Ethernet, SFP transceiver transmission rates increased to 1000Mbps (1000Base). 1000Base rate Gigabit Ethernet SFP transceivers are available in the following interface types: T, SX, LX, LX10, BX10, and the non-standard EX and ZX.

fiber-mart.COM is sure to have the right SFP transceiver for your network! We carry a full line of both name-brand and affordable 100% compatible transceivers of every type your business could possibly need. Contact us today for a free consultation on which standards meet your business needs, or to discuss fiber connectivity network solutions that will best support your future business plans.