400G CFP8 PAM4 & 400GBASE-SR16 NRZ Transceiver Modules

With the price of 100G QSFP28 optics and CFP form factors (CFP module/CFP2/CFP4) dropping down in 2017, 100G technology is becoming more and more popular among data center managers and IT pros in order to cope with the ever-lasting bandwidth needs. However, 100G is not the finish line. CFP multimode source agreement (MSA) demonstrated CFP8 (16X 25 Gb/s) form factor for 400 Gigabit Ethernet at OFC 2017. Although CFP8 module is still in development, it is assured to be popular in the near future. Therefore, this article will have a clearer introduction to 400G CFP8 PAM4 and NRZ modules, and compare with the former CFP modules and 400G CDFP.
Introduction to 400GbE CFP8 Modules
CFP8 module is the latest developing CFP from factor version, which supports eight times and four times the bandwidth density of CFP and CFP2 form factors, respectively. The CFP8 interface supports up to 16 different lanes in each direction with nominal signaling rates of 25Gb/s or 26Gb/s per lane, and either NRZ or PAM4 signaling. As the above image shows, CFP8 is approximately the size of a CFP2 optics. This interface has been generally specified to allow for 16 x 25 Gb/s and 8 x 50 Gb/s mode.
400G CFP8 FR8 and LR8 Transceivers with PAM4 Technology
CFP8 PAM4 optics, compliant with IEEE 802.3bs 400GBASE-FR8 & LR8 electrical interface specifications, offers higher receiver bandwidth capacity for reach up to 2km and 10km. The 400GBASE-FR8 & LR8 consumes less than half the power per GB compared to a 100G CFP4 msa solution. CFP8 optics uses LC duplex fiber cables.
The PAM4 stands for pulse amplitude modulation with four levels. Instead of driving the laser to generate one of the two output amplitudes, like NRZ, PAM4 technology generates four different amplitude levels, meaning a network based on PAM-4 can send twice as much data as an NRZ version.
CFP8 400GBASE-SR16 with NRZ Technology
CFP8 400GBASE-SR16 modules focus on non-return to zero (NRZ) signal modulation Scheme. To use an analogy, it means you’re sending signals in the most simple format: “light on” and “light off.” A ‘1” is transmitted as pulse of light whereas ‘0” is no light output. Based on the currently available fast VCSEL light sources only achieving data rates of 25G, sixteen channels must transmit in parallel to create a 400G data stream.
Due to the design simplicity NRZ, the modulation format of choice for all data rates up to 25Gb/s. 400GBASE-SR16 CFP8 transceivers requires 16 fiber pairs to support a total of 400Gb/s with MPO multimode cables.
What’s New With CFP8 Module?
A CFP8 module is a hot pluggable module. Compared with the former modules, the control and status reporting functions between a host and a CFP8 module use non-data control and status reporting pins on the 124-pin connector. There are three Hardware Control pins, two Hardware Alarm pins, and four pins dedicated to the MDIO interface.
Compared to CFP2/CFP4 MSA Optics
CFP8 is the proposed CFP8 from factor by MSA member companies. It maintains the large size of CFP form factor (nearly the size of CFP2, larger than CFP4 MSA modules), but supports 4x100G i.e. 4x the CFP2. Besides this, CFP8 uses less power than the former CFP form factor modules. There are 400GBASE-SR16 for parallel MMF 16x25G NRZ, and 400GBase-FR8/LR8 duplex SMF 8x50G PAM4 WDM.
CFP8 Vs. CDFP
CFP8 is not the first released 16x25G= 400G modules, but CDFP. 400G CDFP module (CD=400 in Latin), is the four generation CFP form factor. Providing a high level of integration, performance and long-term reliability, the CDFP 400 Gbps interface is available in short- and long-body versions. The specifications are compatible for use with direct attach cables, active optical cables, and connectorized optical modules. The CDFP module will support:
5 meter direct attach cables
100 meter multimode fiber
500 meter parallel single‐mode fiber
2 kilometers of duplex single‐mode fiber
The compact modules are well suited for low power applications using copper, VCSEL or silicon photonics based technology. They also targeted InfiniBand EDR hydra cables and 128GFC applications but so far little market segment pick up. Though relatively new with 2014 and 2015 rev releases, CDFP may be short lived due to the smaller more efficient developing set of CFP8 solutions.
Latest Trend With 400 Gb/s in the Industry
While 400 GbE standard is still a few years away, the need for 400 Gb/s interfaces is here today. The CDFP form factor is already being used in proprietary interfaces to interconnect high performance servers and will soon be used to interconnect switch and router chassis. 400G CFP8 FR8/LR8 PAM4 and 400GBASE-SR16 modules had been displayed at OFC 2017. Finisar, Fujitsu, and oclaro, etc MSA member enterprises will introduce low profile 400G modules in a short period.
These proprietary chassis interconnects have always been massively parallel and will continue because they provide the massive bandwidth needed to interconnect equipment so that multiple chassis perform as one big chassis. While 16 lanes is a fairly wide interface, multiple applications need the maximum amount of bandwidth that can only be provided by many parallel lanes running at the fastest speed available. It seem that CFP8 with the same 16 MPO connectors has much potential than CDFP modules. fiber-mart.COM offers a large stock MSA-compliant optical transceivers, including 100G CFP/CFP2/CFP4 MSA, CXP, and QSFP28 transceiver modules. We will keep in path with the informative world, and provide the best services & telecom products to all of our customers.

Comparing 40G &100G Transceivers modules

As things stand, the trend for high-speed data transmission and high-bandwidth is overwhelming.

As things stand, the trend for high-speed data transmission and high-bandwidth is overwhelming.

now, whether you believe it or not, prepared or not prepared, 40G and 100G have already on the way. To upgrade to 40G or skip it and directly migrate to 100G has become a question for many data center mangers and IT engineers

The growth in 100G comes at the expense of 10G and 40G interfaces. Infonetics says that 10G in carrier networks “is beginning a long decline after an epic 15-year run.”Meanwhile, the market for 40G is “vaporizing,” according to the market research firms.“40G transceivers are ramping up hard as data centers deploy 40GbE, particularly as a high-density 10G interface via breakout cables. 40G QSFP demand growth over single-mode fiber is primarily a result of large shipments to Internet content providers Microsoft and Google,” said Andrew Schmitt, research director for carrier transport networking at IHS Infonetics.

40G and 100G Transceiver Technical Features

40G and 100G have two main types in the data center. Short reach (SR4) for ~100 meters transmission on multimode fiber and Long Reach (LR4) for 100 meters to 10km using single-mode fiber. We can use SR/LR transceivers to connect compute clusters and various switches layers in data centers. 40G transceivers are typically deployed as four 10G lanes in QSFP or CFP MSAs. 40G SR transceiver uses 8 multi-mode fibers, VCSEL lasers, and the QSFP MSA. Using edge-emitting lasers and multiplexes the four 10G lanes onto two single-mode fibers, 40G LR4 reach a 10km distance per CFP MSA, CFP/2 or QSFP28 MSAs. The 40G SR4 and LR4 transceivers can be used in the same QSFP switch port without any issues.

40G,In today’s market, 40G products mainly include 40GBASE-SR4 and 40GBASE-LR4 QSFP+ modules and 40G AOCs. QSFP+ supports both 40G links between racks and high-density 10G links within the rack, especially the 40G QSFP+ breakout AOC which is an ideal solution for 40G migration.“40G transceivers are ramping up hard as data centers deploy 40GbE, particularly as a high-density 10G interface via breakout cables. 40G QSFP demand growth over single-mode fiber is primarily a result of large shipments to internet content providers Microsoft and Google,”said Andrew Schmitt.

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100G SR10 transceivers use 20 multi-mode fibers, VCSELs and the CXP MSA, the 100G LR4 transceivers uses CFP form and 2 single-mode fibers.The market for 100G data center optics is accelerating, but it has yet to be turbocharged by widespread data center deployment in the way 40G QSFP optics have.

The market for 100G data center optics is accelerating, but it has yet to be turbocharged by widespread data center deployment in the way 40G QSFP optics have.The data center likely will be the engine of any overall growth in optical transceiver sales over the next several years. Data centers now represent 65% of the overall telecom and datacom market for 10G/40G/100G optical transceivers. 100

100G is ready here. Tens of thousands of 100G Ethernet links deployed in core routers and carrier switches. Vast majority are CFP modules and CFP2 deployments are now starting. In addition,100G is rapidly expanding. For instance, new optical standards for the data center (100G SR4, CWDM4, PSM4) and new higher density 100G module form factors like CFP4 and QSFP28 are on the way. High port-count 100G switches are being designed and many 100G modules will be used to support high-density 10G and 25G. It is said that 100G and 4x 25G deployments are expected to grow substantially starting in 2015. 100G products mainly include 100GBASE-SR10 and 100G LR4 CFP/CFP2/CFP4 and 120G AOCs. Additionally, QSFP28 as the 100G module form factor of choice for new data center switches is also launched.

If you ask me why 40G Ethernet will be obsolete? The short answer is “cost”. From the technical point, The primary issue lies in the fact that 40G Ethernet uses 4x10G signalling lanes. On UTP, 40G uses 4 pairs at 10G each. Early versions of the 40G standard used 4 pairs, but rapid advances in manufacturing developed a 4x10G WDM on a single fiber optic pair. Each 40G SFP module contains a silicon chip that performs multiplexing so that the switch see 40 gigabits in and 40 gigabits out. It’s similar to Coarse Wave Division Multiplexing when using fiber. When you buy a 40G cable or QSFP, you are paying for the cost of the chip and software, plus the lasers, etc. When using 25/50/100G, the “lane speed” is increased to 25 gigabits per second. For 100G Ethernet, there are four 25G signalling lanes. It’s cheaper to buy 100G with four lanes rather than 40G with a four-lane MUX.

40G/100G transceivers development supports this growth with smaller module form factors for higher port density, lower power consumption per bit and lower cost per bit.

Fiber-MART offers several 40G and 100G Transceiver modules to support the transmission of very high-speed digital signals, providing a bandwidth of 40G or 100G, with distances reaching up to 40 kilometers. These include 40G CFP transceiver and 100G CFP transceivers as well as 40G QSFP+ transceivers. For more informations, you can visit www.fiber-mart.com.pls feel free to contact us for any question. E-mail : service@fiber-mart.com