2017-12-07

Things You Should Know About PSM4


In current interconnection market, 100G QSFP28 transceiver has become a common trend of Ethernet due to its higher bandwidth, high data rate, lower cost and so on. To further keep pace with the market demands, many series of QSFP28 optical transceivers comes into data center, such as QSFP28 100GBASE-SR4/LR4, QSFP28 100GBASE-PSM4, QSFP28 100GBASE-CWDM4 and so on, in which 100GBASE-PSM4 is relatively cost-effective compared with other 100G series optics. Well, this article will have an introduction to things you should know about QSFP28 PSM4 from perspectives of 100G PSM4 definition, 100G PSM4 Specification, advantages of PSM4 and other else.
What’s PSM4?
PSM4, the abbreviation of Parallel Single Mode 4-channels, is a type of single-mode transceiver that uses a parallel fiber design for reaches from up to 2 km and for reaches beyond the limits of 100-meter Short Reach 4-channel (SR4) multi-mode transceivers. It uses four lanes of parallel single fiber to deliver serialized data at a rate of 25Gbps per lane . PSM4 will be the transceiver that enables single-mode fiber to become popular in next-generation data centers due to its low cost and high configurability.
Moreover, PSM4 is built with one laser (instead of four), split into four paths or channels and separately modulated with electrical data signals. Each channel has its own fibers and is separated throughout the link. It doesn’t need a MUX/DEMUX for each laser but it does need a directly modulated DFB laser (DML) or an external modulator for each fiber. PSM4 uses eight-fibers, in which four fibers are for transmission and four fibers are for receiving. A PSM4 QSFP28 module supports link lengths of up to 500 meters over single-mode fiber with 12 fiber MTP/MPO connectors. The light source of PSM4 optic module is a single uncooled distributed feedback (DFB) laser operating at 1310nm.
Brief Introduction Of 100G PSM4 Specification
The 100G PSM4 specification, created by PSM4 MSA(Multi-Source Agreement) group, provides a low-cost solution for long-reach optical interconnects data center. With the data rates of optical interconnects increased, the growth in the scale of data center has created a need for low cost solutions available for at least 500m reaches. The 100G PSM4 Specification is targeted to service that need on a parallel single mode infrastructure, as a critical need of next-generation data centers.
This specification defines a four lane (per direction) 100Gb/s optical interface to single mode fiber(SMF) media. As shown in Figure 1, the 100G PSM4 transceiver module (100G PSM4 module) provides Transmit Optics and Receive Optics between the Host IC and the fiber optic media. A particular form factor, such as QSFP28 or CFP4, is not defined and the 100G PSM4 optical transceiver module may be implemented in various form factors. Since management and control interfaces are with dependent form factor, definition of these interfaces are outside the scope of this specification.
Advantages of PSM4
In the aspect of QSFP28 PSM4 advantages, in addition to the common merits of QSFP28 transceiver module, such as high bandwidth, low insertion loss, high data rate and so on, the most prominent advantage of PSM4 is with the lowest cost. On one hand, the existing 100G Ethernet links with QSFP28 SR4 or LR4 are either too short in transmission distance or too expensive in cost. On the other hand, unlike CWDM4, PSM4 doesn’t need to use an optical multiplexer and de-multiplexer, operating around 1310nm with CWDM technology, as shown in the following picture. However, the high component count drives the cost of CWDM4 modules. Thus, by comparison, CWDM4 is more expensive than PSM4.
Gigalight 100G PSM4
For QSFP28 PSM4 transceiver, Gigalight also launches one type: GQM-SPO101-IR4C(shown as the pic). Besides the characteristics and advantages that common transceiver has, Gigalight PSM4 has its own unique features. This high-performance module for data communication and interconnect applications, integrates four data lanes in each direction with 104Gbps bandwidth. Each lane can operate at 26Gbps up to 2km over G.652 SMF. The electrical interface uses a 38 contact edge type connector. In addition, this module incorporates Gigalight proven circuit and optical technology to provide reliable long life, high performance, and consistent service.




Conclusion
QSFP28 PSM4, as the most cost-effective one type of QSFP28 series transceivers, it’s believed that it will play a key role in future data center by virtue of its various strengths, especially in cost. Simultaneously, it’s possible to be further improved in cost with the development of tech. Let’s expect it together.






2017-12-05

EPON vs. GPON: What Are the Differences?

With the advent of Ethernet tech, the requirements for the bandwidth, network capacity and transmission rate are higher. In recent years, more equipment manufacturers and operators tend to transfer their focus to the optical network access techs, which contributes to the development of FTTH(Fiber To The Home) to some degree. In future optical interconnection market, FTTH will be gradually developed into a trend of access networks. PON (Passive Optical Network) becomes the major tech to serve for it. To further keep pace with market’s demands, EPON (Ethernet Passive Optical Network )and GPON(Gigabit Passive Optical Network) emerges from PON and become  popular versions of it. Maybe one is curious about difference between EPON and GPON. Well, then an introduction will be made in the form of EPON vs. GPON by Gigalight.
What’s EPON?
As the name implies, EPON tech is a version of PON tech based on Ethernet, offering point-to-multipoint network access with lower installation and maintenance costs. EPON tech is standardized by IEEE802.3EFM group and endowed with a standard, IEEE802.3ah. In this standard, the PON tech is integrated with Ethernet tech and a new physical layer specification applied in the EPON system and extended Ethernet data link layer protocol to realize the TDM access of the Ethernet frame in the PON with point-to-multipoint architecture.
In the physical layer, single fiber WDM Technology (downstream wavelength is 1490 nm, upstream wavelength is 1310 nm) are specified for application in IEEE 802.3-2005to realize bidirectional transmission via single fiber. Meanwhile, the two PON optical interfaces, the 1000 BASE-PX-10 U/D and 1000 BASE-PX-20 U/D, are defined to respectively support the maximum transmission distances,10 km and 20 km. In the physical coding sublayer, the EPON system inherits the original standard of Gigabit  Ethernet, adopts 8B/10B line coding and standardized upstream and downstream symmetric 1 Gbit/s data rate (line rate is 1.25 Gbit/s).
What’s GPON?
GPON tech is the latest-generation broadband passive optical access tech based on ITU-TG.984.x standard, which is with high bandwidth, high efficiency, wide coverage, rich user interface and so on. It's considered as an ideal tech to realize broadband access network services.
GPON uses an IP-based protocol and either ATM or GEM (GPON encapsulation method) encoding. Data rates up to 2.5Gbps are specified and it is very flexible in what types of traffic it carries. GPON enables "triple play" (voice-data-video) and is the basis of most planned FTTP (Fiber to the Premises) applications in the near future. Simultaneously, it also applies optical wavelength division multiplexing (WDM) so that a single fiber can be used for both downstream and upstream data. A laser on a wavelength (λ) of 1490nm transmits downstream data. Upstream data are transmitted on a wavelength of 1310 nm. If TV is being distributed, a wavelength of 1550nm is used.


Moreover, It’s with 1.25Gbit/s or 2.5Gbit/s downstream or upstream bandwidths scalable from 155Mbit/s to 2.5Gbit/s. GPON does not support multi-cast services, which makes support for IP video more bandwidth-consuming.
As the main forces of optical network access, EPON and EPON have their own advantages for competition, as well as compensate for each other. For the difference between EPON and GPON, it will be shown in the following EPON and GPON comparison.
EPON vs. GPON Which One Is Better
1.    In data rate, GPON is higher  than EPON. EPON uses standard 802.3 Ethernet data frames: IEEE 802.3 standard, ratified as 802.3ah-2004 for 1.25 Gbps (1.0 Gbps prior to 8B/10B coding) and IEEE 802.3av standard for 10Gbps (10G-EPON). The upstream and downstream data rate of EPON is symmetrical. While GPON supports various bit rate options using the same protocol, including a symmetrical data rate of 622 Mbps in both downstream and upstream, a symmetrical data rate of 1.25Gbps in both streams, as well as a data rate of 2.5Gbps in downstream and a data rate of 1.25Gbps in upstream. 2.5Gbps of downstream bandwidth and 1.25Gbps of upstream bandwidth are the data rates supported by typical GPON systems. Thus, one can decide the upstream and downstream data rate depending on the requirements, and then choose the corresponding optical transceiver modules. It is more flexible than EPON.
2.    In split ratio, GPON is neck and neck with EPON. Split ratio mainly limited by the performance index of optical modules means the quantity of ONU user port in one OLT interface. The standard split ratio of EPON is 132. While the split ratio of GPON includes these types: 1:32; 1:64; 1:128. Actually, the split ratio of EPON can also reach higher, such as 1:64; 1:128. And the control protocol of EPON can support more ONUs. The high split ratio will bring about  the sharp rising in costs. Although GPON is able to provide multiple options, and it has few benefits in costs. In addition, the insertion loss of PON tech is 1518dB, and higher split ratio will shorten the transmission distance. When the split ratios are 1:16 and 1:32, the maximum physical distance of GPON can respectively reach 20km and 10km, which is same as that of EPON.
3.    In the cost, the EPON is more cost-effective than GPON. Generally speaking, the cost of GPON or EPON deployment consists of that of OLT, ONU/ONT and passive optical components. An ODN is combined with fiber cable, cabinet, optical splitter, connector and so on. For the same amounts of users, the cost for the fiber and cabinet with EPON is similar to that of GPON. The cost of OLT and ONT is decided by the ASIC (Application Specific Integrated Circuit) and optical transceiver modules. The GPON chipsets available in the market are mostly based on FPGA (Field Programmable Gate Array), which is more expensive than the EPON MAC (Media Access Control) layer ASIC. There are only several chipset vendors who can provide GPON chipsets, and it is likely that the price of GPON equipment cannot be reduced rapidly. The optical module of GPON is also more expensive than EPON. When GPON reaches deployment stage, the estimated cost of a GPON OLT is 1.5 to 2 times higher than that of an EPON OLT, and the estimated cost of a GPON ONT will be 1.2 to 1.5 times higher than that of an EPON ONT.
4.    In QoS(Quality of Service), GPON is superior to EPON. Ethernet protocol has no inherent QoS capability. On account that a PON system is not viable without QoS, most vendors provide it by using VLAN (Virtual Local Area Network) tags. Without automatic provisioning of VLAN tags, to a large extent, they are manually provisioned. GPON is integrated with QoS to make it better than EPON, due to that EPON QoS is with high cost relative to GPON.


5.    In OMA(Operation Administration and Maintenance), GPON has more advantages than EPON. EPON does not take OMA into consideration, and just simply defines the remote failure indication for ONT, loopback and link monitoring. On the contrary, GPON defines the PLOAM(Physical Layer OAM) in physical layer and OMCI(ONT Management and Control Interface) in the high-level layer. GPON has OAM management in multi-layers. PLOAM is applied to realize the data encryption, state inspection, error code monitoring. OMCI is applied to manage the higher-level layer services, such as ONU functional parameters, the types and quantity of T-CONT, QoS parameters, information of appliance for deployment and performance statistics, to implement the OLT management for the ONT deployment, fault diagnosis, performance and safety.

Conclusion
Although both GPON and EPON have their own features and merits, and to some degree, they compensate for each other. In performance, GPON is superior to EPON, but inferior to EPON in costs. GPON is coming up from behind. For the future broadband access market, the co-existence and 

2017-11-30

Things We Should Know About SFP Transceiver

In today’s data center, fast Ethernet is out of date.  What takes the place of it is SFP transceiver. Although SFP transceiver is commonly applied in the data center, and there are still many people knowing little of it, such as SFP transceiver types, SFP applications, SFP use tips and so on. Now this article will introduce things we should know about it there.

What Is SFP Transceiver?
The small form-factor pluggable (SFP) is a compact, hot-pluggable optical module transceiver used for both telecommunication and data communications applications. The form factor and electrical interface are specified by a multi-source agreement (MSA) under the auspices of the Small Form Factor Committee. It is a popular industry format jointly developed and supported by many network component vendors.

SFP Transceiver

An SFP interface on networking hardware provides the device with a modular interface that the user can easily adapt to various fiber optic and copper networking standards. Existing SFP transceivers support SONET, gigabit Ethernet, Fibre Channel, and other communications standards. Due to its smaller size, the SFP has replaced the gigabit interface converter (GBIC) in most applications; the SFP is sometimes referred to as a Mini-GBIC. In fact, no device with this name has ever been officially defined in the MSAs.

Types of SFP Transceiver
SFP transceivers are available with a variety of transmitter and receiver specifications, allowing users to select the appropriate transceiver for each link to provide the required optical reach over the available optical fiber type. With the respect to SFP transceiver types, it can be sorted out according to transmission rate, wavelength. The introductions of them are as below:
Classified according to the SFP transceiver rate, it includes 155M/622M/1.25G/2.125G/4.25G/8G/10G, in which 155M and 1.25G are usually applied. Besides, 10G tech is maturely developed, and the demands for it tend to rise.
Sorted according to the SFP wavelength, it consists of 850nm/1310nm/1550nm/1490nm/1530nm/1610nm, in which 850nm wavelength belongs to multimode, and its transmission distance is less than 2KM; 1310nm/1550nm wavelength belongs to single mode, and the transmission distance is over 2KM. Relatively speaking, the prices of 850nm, 1310nm and 1550nm wavelength are lower than the other three types. Moreover, bare optical modules without signs are easy to get mixed up, thus manufacturers usually make a clarification in the colours of pull rings. For example, pull rings of  modules differ in colors, which means they distinguish in wavelengths. Black represents 850mn wavelength; blue represents 1310mn wavelength; yellow represents 1550mn wavelength; and purple represents 1490mn.
In addition, it can also be divided into these categories, such as Gigabit Ethernet SFP, Fast Ethernet SFP, BiDi SFP, CWDM SFP, DWDM SFP, Fiber Channel SFP and so on, in which Gigabit Ethernet SFP and CWDM SFP are relatively common ones (Gigalight will provide several ones for reference at the end of this article, shown as the tables)

Applications
SFP sockets are found in Ethernet switches, routers, firewalls and network interface cards. Storage interface cards, also called HBAs or Fibre Channel storage switches, also make use of these modules, supporting different speeds such as 2Gb, 4Gb, and 8Gb. Because of their low cost, low profile, and ability to provide a connection to different types of optical fiber, SFP provides such equipment with enhanced flexibility.

Use Tips
If module is improperly operated when used, it may not work. Once this situation happens, things that should be done first is to check it carefully and analyze the causes. The failure of optical transceiver usually includes these two types: the failure of transmitting terminal and receiving terminal. The commonly-seen reasons of failure are as below:
1.    The contaminated interface of fiber connector result in the secondary contamination of optic module’s optical port
2.    Optical port of optic module is exposed to the air, and dust into it brings about contamination.
3.    Optic fiber connector is with bad quality.

Conclusion
Although the needs for higher rate products will be increased with the development of tech, and SFP transceiver will still be in the optic market for a long time due to its advantages in miniaturization, port density and so on. This article have a relative comprehensive introductions to SFP transceiver, and it’s believed that it will be beneficial to us in the future use of SFP transceiver.

More Information :
1.    Gigalight Gigabit Ethernet SFP:
Gigalight Gigabit Ethernet SFP
Part Number
Description

GE-GB-P3RT-E
Compliant with the Gigabit Ethernet and 1000BASE-T standards as specified in IEEE 802. 3-2002 and IEEE 802.3ab, which supporting 1000Mbps data- rate up to 100 meters reach over unshielded twisted-pair category 5 cable.
GP-8524-S5TD
Supporting data-rate of 1.25Gbps and 550m transmission distance with MMF. All modules satisfy class I laser safety  requirements.
GP-3124-L4TD
Supporting data-rate of 1.25Gbps he transceiver consists of three sections: a DFB laser transmitter, a PIN photodiode
integrated with a and 40km transmission distance with SMF
GP-5524-L8TD
Supporting data-rate of 1.25Gbps and 80km transmission distance with SMF. Compatible with SFP Multi-Source Agreement (MSA) and SFF-8472.

2.    Gigalight CWDM SFP Transceivers:
Gigalight CWDM SFP Transceivers
Part Number
Description

GPC-4903-08TD
Supporting data-rate of 155Mbps and 80km transmission distance with SMF. Compatible with SFP Multi-Source Agreement (MSA) and SFF-8472.
GPC-5103-08TD
Supporting data-rate of 155Mbps and 80km transmission distance with SMF. Compatible with SFP Multi-Source Agreement (MSA) and SFF-8472.
GPC-5303-08TD
Supporting data-rate of 155Mbps and 80km transmission distance with SMF. Compatible with SFP Multi-Source Agreement (MSA) and SFF-8472.
GPC-5503-08TD
Supporting data-rate of 155Mbps and 80km transmission distance with SMF. Compatible with SFP Multi-Source Agreement (MSA) and SFF-8472.
GPC-5703-08TD
Supporting data-rate of 155Mbps and 80km transmission distance with SMF. Compatible with SFP Multi-Source Agreement (MSA) and SFF-8472.
GPC-5903-08TD
Supporting data-rate of 155Mbps and 80km transmission distance with SMF. Compatible with SFP Multi-Source Agreement (MSA) and SFF-8472.
GPC-6103-08TD
Supporting data-rate of 155Mbps and 80km transmission distance with SMF. Compatible with SFP Multi-Source Agreement (MSA) and SFF-8472.


Note: Infiberone is the online store of Gigalight

2017-10-10

A Good Chance of Lifetime for You to Show Your Talents In the Communication Industry

Maybe you have been looking forward to a chance to display your talents for a long time. Now, fortunately, Gigalight right has a good opportunity for you!
Once you miss it, maybe you will be regretful! Therefore, Don't wait, just visit here to catch it: https://www.infiberone.com/Plate_Detail_388.html
Gigalight Tech Center Address In Wuhan

2017-09-20

Gigalight 100G Single Optical Transceiver Has Been Admitted By Domestic DPI Manufacturers

Nowadays, DPI industry is developed rapidly. In the development waves, the demand of Network security is constantly raised, and the personalized recognition for the users’ service is also gradually strengthened. Therefore, how to meet the market demands of data center, manufacturers and Internet enterprises,has recently become the crucial topic of Gigalight.
However, at the process of the implement from the gradual upgrading of 10G POS/WAN-40G/100G to the enrichment of product line, the improvement of delivery capability, the making of long-term goals, Gigalight has made breakthrough achievements in these aspects, seen from the truth that Gigalight continuously has won the bids  of the leading DPI device manufacturers in this field and has gained their supports. Now, the below is the detailed introduction about these measures:

Measure 1: Providing Rich Product Lines
For an enterprise, products are the core. Rich product lines is able to meet the needs of manufacturers in many aspects and to reduce the combination costs. Therefore, Gigalight spares no effort to build one rich product line, 100G QSFP28 LR4/CFP LR4/CFP2 LR4 series single optical module product line, satisfying the needs of clients about the high bandwidth. Meanwhile, by the tech innovation , the adoption of self-developed ROSA components lead to the low-cost products, bringing DPI manufacturers practical benefits. In addition, the 100G CFP4 LR4 also can be customized and achieve the multiple options of products.


Measure 2: Improving the Delivery Capability
For the professional optical transceiver manufacturers, they are not only with the ability to offer clients high-quality and high-performance optical transceiver solutions, but also with the delivery capability to share the delivery pressure of manufacturers.

Recently, Gigalight DPI series 100G single optical transceiver continuously won the bids of leading device manufacturers. Faced with the short delivery time, Gigalight gave the manufacturers a satisfying result by virtue of their strong delivery ability and high quality products, by which they are highly admitted by domestic DPI manufacturers and DPI market is also injected a new fresh air. 

Measure 3: Making The Long-Term Goals
For a company, a long-term  goal is the motivation of producing and the soul of offering higher-quality service for clients. Gigalight combines the market needs and its own tech strengths to achieve the goal, in the later two years’ DPI market, making the 100G product’s cost at $100 via scale and new tech to get the DPI devices applied widely, to continuously provide manufacturers with high-quality and low-cost optical module products and to offer more low-cost products to DPI manufacturers for options.

Above all is the Gigalight news about 100G single optical transceiver. If you want to know more, welcome to contact us at any time.

Note: Gigalight is the head office of Infiberone.

2017-09-10

Consideration on the Applications of 100GE QSFP28 in the Large-Scare Data Center

1.The Changes On the Structure of Data Supercomputing Center Lead to the 100GE ports’ rapid increasing in Number, Showing the importance of Structure 
With the rapid increasing of IP flux , the accelerated infiltration of cloud computing and virtualization, and the fast burstout of IDC inner flux, large-scale data center is developed toward new and flat leaf- spine network structure continuously. Traditional three-layers network structure of data center will be replaced by new and flat leaf- spine network structure. 

Meanwhile, With the rapid increasing in quantity of interconnection ports between leaf converters and spine converters, the demands on high-end 40GE/100GE optical transceiver also rise rapidly with it. It’s predicted by the Third-Part Institution that 40GE/100GE high-speed optical modules’ quantity ,needed by leaf- spine network structure, is 15-30 times the quantity of Traditional three-layers network structure for the large-scale data center. In addition, high-speed optical modules will be upgraded from10G/40G optical module to 100G/200G, especially is 100G optical module, demands for it will be raised in a large scale. 


2.Exploration On the Background of Rapid Increasing for 100G Optical Module, Showing the Importance of Wiring 
It’s predicted by the Third-Part Institution, Ovum, that the deployed quantity of 100G single-mode optical module will be close to or exceed the one of 100G multimode optical module, With the rapid increasing in quantity of interconnection ports between leaf converters and spine converters, and the distance among converters extended . Shown as the above pic, in the data center with 500,000 ft2, the quantity of TOR/Leaf/Spine converters and 100G single-mode/multimode optical modules has been listed clearly. We need to make some theoretical exploration:  

A. Difficulties in wiring space due to the density of scales and devices. For these difficulties, data center may prefer to choose the 100G CWDM4 optical module in the long-distance interconnection, because it saves the fiber wiring space and the reduces fiber wiring difficulties superficially at least. But such kind of savings lead to self-limitation on account that wiring structure has no good designs from the beginning. Therefore, deep consideration is necessary before deploying it.

B. Based on the comprehension for scale and different techs, PSM4 and CWDM4 optical module will be deployed. They should be used on the basis of comprehensive assessment for their stability, power dissipation and working life. Technically evaluating, CWDM4 optical module is more complicated than PSM4 optical module. 

But whether the complex standards constituted by industry association are reasonable is worth reflecting. The performance of CWDM4 optical module is becoming higher and higher, and the large-scale usage for it will exist no dangers under the guarantee of 65 or double-85 test’s reliability. But we haven’t seen the improvements on techs from PSM4 to CWDM4, and it seems that everything is like factitious tech barriers and trends. Our viewpoints on CWDM4 are that it’s just an extension for PSM4 optical module, not another application tech superior to the former. The large-scale applications for the PSM4 and CWDM4 may be a miracle in the data center.

C. The wiring structure of data center has a great influence in the cost of large-scale data center. What we should focus on is wiring, not devices, which we consider as the deviation of industry’s focus. When we are keen on studying converters and servers with high speed and high performance, we must have wiring techs suitable for them, which is just like that inspection for subgrade , the assurance for the structure and plot ratio of the building, should be done before building a house. If everything about it weren’t confirmed, the built house may be with hidden safety dangers or not good in Fengshui theory. 

Similarly, if we don’t confirm the basic wiring, the PCB layout of electrical products, in advance, the performance of them will be at a mess. If a data center is built hastily, no differences with previously-built computer room, and it will truly enter into the deserted stage. 

D. We must have a long-term consideration on data center, in which long term must be a relative concept. How long it should be must integrate the present progress and demands on dealing with the datas in the data center. If the sources of rapid increasing needs aren’t confirmed, frankly speaking, the distribution for a new data center will be finally proved to be impractical and wasteful when it adopts immatural or the most advanced products. 

In addition, the future level about interconnection tech of data center still isn’t confirmed, even though certain paths made by industry association aren’t necessarily correct in the direction. Now, industry association is used to making many decisions hastily, which usually leads to efforts in the incorrect direction. 


3.Advantages of 100G PSM4/100G CWDM4/100G LR4 Optical Module And The Importance of Choices.
A comparison about the integrated parameters of 100G optical module in wavelength, optical connector, fiber types, working distance, the interior of optical module with/without MUX/DEMUX, system terminal with/without needs of FEC function, the power dissipation of optical module and so on, in this table, used for customers’ reference:    

100GBASE-SR4(100 m) and 100GBASE-LR4(10 km) are defined by IEEE. Due to the needs from data center customers, 100G CWDM4 and 100G PSM4 are also defined by MSA, making up for the gap in needs between 100meters and 10KM. Compared with 100GBASE-LR4, 100G CWDM4 and 100G PSM4 have the lower cost advantages and their application distances cover 2 KM. And 100G PSM4 adopts parallel single-mode tech and MPO APC 8°connector with eight fibers, with the lowest cost in the 100G single-mode transmission tech. 

Besides, in the market, there is 100G PSM4 made on the basis of silicon photonics tech or traditional 4x mini TOSA packaging tech. Similarly, they have the advantages on the low cost. Sometimes two-fibers CWDM4 are considered to be more economical and practical than multi-fibers PSM4. However, the results is contrary:
1. PSM4 increases the complexity of wiring density, and CWDM4 results in the complexity of devices’ performance. 

2. PSM4 is still available to extend in space, and CWDM4 has gotten into the endless loop.

3. PSM4 is with higher stability and reliability in the wavelength, and in the present whole chain, CWDM4 still exists problems in reliability and have no way to pass the double-85 test. 

4. PSM4 is with lower power dissipation, and CWDM4 needs interior temperature or control from the external environment to reach the ideal power dissipation on account that the narrow space of module causes the heat dissipation problem.

5. PSM4 is easier to manage because of its clear link path, and CWDM4’s link path is not clear. 

Whatever optic product manufacturers of data center want, the producers of optical module can provide it for them. And it’s proved that there exists direction problems in the previous comparison of advancement and superiority between optical module/ devices and data center. All techs about optical module will tend to be same in the performance and be more stable one year later. We should concentrate on the improvement of wiring techs and more economical and practical items. 

With the progress in the optical interconnection tech, data center will tends to be at the state of instant evolution and flourish, which means continuous devotion and evolution and is with no ultimate products. The combination process from 1G to 100G and then from 400G to 1T, will be the final and vital formation of data center, based on the combination of different applications.  

4.Introduction about 100GE QSFP28 Data Center Application Cases
1. In June, 2016, Azure data center started to adopt Intel 100G QSFP28 PSM4 silicon photonics optical module volumely. Azure cloud service have been used in the 140 countries, and over 90% of Fortune 500 enterprises have applied Microsoft Azure, which will be immediately expanded to 34 areas on the basis of existing 28 areas in the world where more than 100 data centers were invested to build. The number will exceed the sum of AWS, Google and AliCloud. 

2. In February, 2017, Facebook specially released OCP CWDM4 standards to deploy 100G QSFP28 CWDM4 scalely. For the volume production and low cost, Facebook has loosened part of standards, such as working temperature, optical emission power, receiving sensitivity and optical link path index. At present, Facebook has purchased 100G QSFP28 CWDM4 optical module.

5.Recommendation on the Infiberone 100GE QSFP28 Products 
By their own strength, Infiberone developed 100G QSFP28 CWDM4 optical module with cost benefit by themself. This optical module adopts self-packaged optical engine, and some micro components are assembled inside, such as DFB laser(1271nm,1291nm,1311nm and 1331nm)of 4-channels 25Gbps uncooled CWDM, 4-channels optical detector, CDRs, micro AWG chip and so on. Under the total air temperature(0~70℃), its typical power consumption is lower than 2.6W, and its optic eye diagram margin is higher than 20%. 

In addition, its sensitivity is(pre-FEC 1E-5BER OMA)<-10.5dBm. Its error rate guarantees BER is higher than 1x10-12 under the application of post FEC. Meanwhile, it uses Duplex LC optical interface and meets the needs of 2km transmission distance. Infiberone will get about to producing it volumely in the forth quarter of 2017.
Infiberone QSFP28 PSM4 optical module shows a good performance under the  -5°C/25°C /55°C. The uniformity and consistency of four channels are accorded with design requirements and its optical eye diagram margin is higher than 15% under the -5°C/25°C /55°C . and sensitivity is higher than-9.5dbm(1E-5) constrained by agreements, meeting the needs of data center applications in the fiber transmission distance, no less than 2km. the success on the development of Infiberone 100G PSM4 optical module, means that it officially has its own essential tech and skill in the single-mode optical engine. In addition, it will start to produce this product volumely in the third quarter of 2017.

Infiberone set about to developing data center single-mode product line and its packaging techs in 2015 and officially sold 100G QSFP28 LR4 (DML)products in the end of 2016. 100G QSFP28 LR4 optical module’s power consumption is lower than 3.5W, and uses self-packaged optical engine, ROSA. In addition, its transmission distance can reach 10km when it’s connected with single-mode fiber. It conforms to IEEE802.3ba 100GBASE-LR4 and QSFP+ MSA standards. Its typical power consumption is lower than 2.6w under the total air temperature (0~70℃) and its optical eye diagram margin is higher than 20%. In the first quarter of 2017, Infiberone gets down to producing this product volumely.

For Infiberone second-generation 100G QSFP28 SR4 with lower power consumption, under the CDR working condition, its typical power consumption under the indoor temperature and 70℃ respectively is 2W and 2.2W, reaching the power consumption level ,MAX POWER 2.5W in the SFF-8436 V4.8 MSA Power level 3. 

Meanwhile, it meets the standards, such as IEEE 802.3bm 100GBASE SR4, InfiniBand EDR, 32GFC and so on, downward compatible with 10GE, completely suitable for transmission applications on transmission, such as OM3 75meters fiber transmission and OM4 100meters fiber transmission. Under the true test conditions, OM4 fiber with 100meters transmission distance has no any error code according to the stricter error rate test standards. 100G QSFP28 SR4 adopts the lens tech and optical engine tech self-developed by Infiberone, supporting the digital diagnostic function and integrating data channel of 25Gbps with 4 channels and receiving-and-sending function. 

In addition, 100G QSFP28 SR4 optical module is with higher performance in optical eye diagram, sensitivity for receiving and electric eye chattering. At present, this product has been produced volumely. The VCSEL optical module tech and production tech platform are self-developed by Infiberone, and their related cost is close to critical value by optimization whether it’s in coaxial packaging or COB tech. Advantages on the scale of delivering has been strongly supported by suppliers. 

Conclusion:
Infiberone is the advocator of 100G QSFP28 optical module products and tech marketing in date center ,and maintains a keen insight into technology and cost . In 2016, Infiberone started to arrange the layout about all series of 100G QSFP28 optical module and solutions. In March,2017, 100G PSM4 optical module was officially pushed out. And in July,2017, the sample of 100G QSFP28 CWDM4 optical module was developed, which used AAWG chip and unique COB tech platform, with good stability in temperature, suitable for the capacity expansion of data center with parallel structure or optical interconnection structure of wavelength division multiplexing style data center. 

The successful development of 100G QSFP28 CWDM4 and 100G QSFP28 PSM4 optical module has built a new competitive strength for Infiberone data center market strategy, and will also be one of the most powerful suppliers of 100G optical module in the domestic data center.


Note: Infiberone is a sub-brand of Gigalight, we focus on high-end optical network devices, mainly supplying industrial-grade optical transceivers and professional optical interconnection components for data centers. With more than 10 years' experience in optics industry, we now have professional R&D team(more than 100 engineers) and stable supply ability.