Tag Archives: MPO connector

Can 40GBASE-LR4 Be Used for 4x10G?

We know that 40GBASE-SR4 QSFP+ transceiver can be used for 4x10G SFP+ connections, because it offers 4 independent transmit and receive channels, each capable of 10G operation for an aggregate data rate of 40G over 100 meters of OM3 MMF or 150 meters of OM4 MMF. However, for 40GBASE-LR4 QSFP+ transceiver, it is commonly utilized over long transmission distance of SMF in 40G network applications. Can 40GBASE-LR4 be used for 4x10G? The answer depends and this article will focus on this question.

40GBASE-LR4 CWDM QSFP+ Transceiver Cannot Be Used for 4x10G

The 40GBASE-LR4 CWDM QSFP+ transceiver, such as QSFP-40GE-LR4, is compliant to 40GBASE-LR4 of the IEEE P802.3ba standard. It contains a duplex LC connector for the optical interface. The maximum transmission distance of the transceiver is 10km over SMF. In the transmit side, the 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 then multiplexes them into a single channel for 40G optical transmission, propagating out of the transmitter module from the SMF. Reversely, the receiver side accepts the 40G CWDM optical signals input, and demultiplexes it into 4 individual 10G channels with different wavelengths. Each wavelength channel is collected by a discrete photo diode and output as electric data after being amplified by a transimpedance amplifier (TIA). Therefore, 40GBASE-LR4 CWDM QSFP+ transceiver cannot be used for 4x10G. It cannot be split into 4x10G, because it uses 4 wavelengths on a pair of single-mode fiber with LC duplex connector, and does not allow itself to split into 4 pairs without substantial complexity to split out the wavelengths.

Working Principle of 40GBASE-LR4 CWDM QSFP+ Transceiver

40GBASE-LR4 PSM QSFP+ Transceiver Can Be Used for 4x10G

The 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 on 10km of single-mode fiber. The transmitter side accepts electrical input signals compatible with common mode logic (CML) levels. All input data signals are differential and internally terminated. The receiver side converts parallel optical input signals via a photo detector array into parallel electrical output signals. That’s to say, the parallel optical signals are transmitted parallelly through 8 single mode fibers. As a result, 40GBASE-LR4 PSM QSFP+ transceiver can be used for 4x10G, because it uses parallel (ribbon) fiber with MTP/MPO connector, which allows the creation of 4 fiber pairs.

Working Principle of 40GBASE-LR4 PSM QSFP+ Transceiver

Note: From an optical transceiver module structure viewpoint, PSM uses a single uncooled CW laser which splits its output power into four integrated silicon modulators. Therefore, it allows for splitting into 4x10G (single-mode).

Conclusion

In a world, the answer of question “Can 40GBASE-LR4 be used for 4x10G?” depends. The 40GBASE-LR4 CWDM QSFP+ transceiver cannot be split into 4x10G, while for 40GBASE-LR4 PSM QSFP+ transceiver, it cab be used for 4x10G. To put it simply, 40G QSFP+ transceiver which is with MTP/MPO interface can be used for 4x10G connections, otherwise, it can only support 40G link. The 40G QSFP+ transceivers mentioned above can be found in FS.COM, if you want to know more details, please visit our site.

Parallel Optics Technology Overview

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).

12-fiber-MTP-parallel-connection-1024x366

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.