Archive | August 2017

Introduction to Semiconductor Optical Amplifier (SOA)

Optical amplifier, with the introduction in 1990s, conquered the regenerator technology and opened doors to the WDM technology. It is mainly used to amplify an optical signal directly, without the need to first convert it to an electrical signal. There are many types of optical amplifiers, namely Raman amplifiers, erbium doped-fiber amplifiers (EDFAs), and semiconductor optical amplifier (SOA). This article will make a clearer introduction to SOA amplifier, and analyze its advantages and disadvantages.

transport network system

The Basics of Semiconductor Optical Amplifier (SOA)

SOA optical amplifiers use the semiconductor as the gain medium, which are designed to be used in general applications to increase optical launch power to compensate for loss of other optical devices. Semiconductor optical amplifiers are often adopted in telecommunication systems in the form of fiber-pigtailed components, operating at signal wavelengths between 0.85 µm and 1.6 µm and generating gains of up to 30 dB. Semiconductor optical amplifier, available in 1310nm, 1400nm, 1500nm, 1600nm wavelength, can be used with singlemode or polarization maintaining fiber input/output.

Key Points of SOA Amplifier

  • 1310 nm, 1400 nm, 1550 nm and 1610 nm wavelength selectable
  • High fiber-to-fiber gain of 20 dB
  • Up to 16 dBm output
  • 1 MHz with 10 ns pulse width (optional)
  • PM Panda fiber input/output (optional)
  • Similar to lasers, but with non-reflecting ends and broad wavelength emission
  • Incoming optical signal stimulates emission of light at its own wavelength
  • Process continues through cavity to amplify signal

Working principle of SOA amplifier

The basic working principle of a SOA is the same as a semiconductor laser but without feedback. SOAs amplify incident light through simulated emission. When the light traveling through the active region, it causes these electrons to lose energy in the form of photons and get back to the ground state. Those stimulated photons have the same wavelength as the optical signal, thus amplifying the optical signal.

working principle of SOA
SOA Over EFDA in DWDM Networks

As the solution below, 120km Metro Networks by Using an SOA amplifier. You may wonder why not use EDFA in the above networks.

SOA amplifier

Theoretically, SOA optical amplifiers are not comparable with EDFA in the terms of performance. The noise figure of SOA optical amplifier is typically higher, the gain bandwidth can be similar, SOAs exhibit much stronger nonlinear distortions in the form of self-phase modulation and four-wave mixing. Yet, the semiconductor optical amplifier is of small size and electrical pumped, which is often less expensive than EDFA. Additionally, SOA can be run with a low power laser.

How to Choose SOA Optical Amplifier?

When selecting SOA amplifier, you have to check the every detailed parameter in the product data sheet. But, seriously, do you understand it? No, please read the following part.

The key parameters used to characterize a SOA amplifier are gain, gain bandwidth, saturation output power and noise.

Gain is the factor by which the input signal is amplified and is measured as the ratio of output power to input power (in dB). A higher gain results in higher output optical signal.

Gain bandwidth defines the range of bandwidth where the amplification functions. A wide gain bandwidth is desirable to amplify a wide range of signal wavelengths.

Saturation output power is the maximum output power attainable after amplification beyond which no amplification is reached. It is important that the SOA has a high power saturation level to remain in the linear working region and to have higher dynamic range.

Noise defines the undesired signal within the signal bandwidth which arises due to physical processing in the amplifier. A parameter called noise figure is used to measure the impact of noise which is typically around 5dB.

Conclusion

SOA amplifier is the economic, high-performance solution for long-hual WDM networks. SOA amplifier, due to its features, can be used in Booster and in-line amplification, optical network, general purpose test and measurement and fiber sensing. However, it also has its limit. In semiconductor optical amplifiers, electron-hole recombination occurs which will affect the performance of the whole line. FS offers EDFA, SOA, Raman optical amplifiers of excellent quality and price. For more detailed information, please feel free to contact us.

Original Source: Semiconductor Optical Amplifier

OM5 Fiber Cable – Is It Worthwhile for 40G/100G SWDM4 Cabling Solution

OM5 multimode fiber, as the advanced version of the old OM4 fiber, is thought to be the future of multimode cabling. It is the Wideband multimode fiber (WBMMF) that can support wavelengths between 850nm and 953nm. It is also designed to support the short wavelength division multiplexing (SWDM)—one of the new technology for 40G/100G connection. However, will it be the ideal transmission medium for 40GbE/100GbE cabling solution?

How OM5 Fiber Developed

Over the past thirty years, multimode fiber has been evolved from OM1 to OM5 multimode fiber. OM1 and OM2 fiber, released at the end of 20th century, are the legacy 125µm multimode fiber that are working fine in 10Mb/s, 100Mb/s and 1000Mb/s cabling solution. However, with the high speed data rate like 10Gb/s, 40Gb/s, 100Gb/s and beyond coming into our life, multimode cabling (OM1 and OM2 ) with LEDs can not meet the requirement. The laser-optimized OM3 and OM4 has been developed subsequently. OM4 fiber cable, with the internal construction, possess higher modal bandwidth than OM3 fiber, which is commonly used fiber medium for 40G/100G connection.

OM1-OM5 fiber

But there is a problem. In a 40G layout, fiber optic technicians have to use one MTP fiber and 4 OM4 duplex fibers (total 8 fibers), which is obvious not preferable for high-density cabling networks. So here comes the OM5 fiber. By utilizing SWDM technology, it can greatly reduce fiber count into 2 fibers (4×10G) in 40G networks, 2 fibers (4×25G) in 100G links. OM5 is the lime green multimode fiber, displayed as follows.

OM5 Fiber

OM5 Fiber for 40G/100G SWDM4 Cabling Solution

Reduce fiber count for 40G/100G connection—OM5 fiber as the advanced version of OM3/OM4 fiber, is backward compatible with OM3 and OM4 fiber cabling. And with the SWDM technology, this fiber can only use two OM5 fibers and 40/100G SWDM4 transceivers in 40G and 100G SWDM4 cabling.

Longer-transmission distance—OM5 is designed and specified to support at least four WDM channels at a minimum speed of 28Gbps per channel through the 850-953 window. Compared to OM4 fiber cable, it is specified only to work at the 850 nm window. OM5 multimode fiber delivers higher value to network owners for distances up to 440m (for data rates up to 40Gbps), and allows for smooth migration to 400Gbps for distances up to 150m. While OM4 fiber cover the distance of 350m, 100m over 40G/100G respectively.

Easy management & installation—in 40G/100G network, multimode connectivity together with MTP/MPO systems makes for a more user-friendly solution for data centers as well as building and campus backbones, especially in cable installation, troubleshooting, cleaning, and overall maintenance.

FS OM5 Cable Solution

FS offer Lime green OM5 fibers. All our OM5 fiber cables are guaranteed by End Face Geometry Test, Continuity Test, and 3D interferometry Test to be high quality. Available in LC, SC, FC, ST, etc. Connectors, and the cable length of OM5 fiber can be provided from less than 1 meter to more than 100 meters, which will well meet the needs for 400m transmission of 40G SWDM4 QSFP+ module and 100m transmission of 100G SWDM4 QSFP28 module, as well as the links on the same rack or row.

fiber optic cable

Not only the OM1/OM2/OM3/OM4/OM5 multimode fibers are provided at FS.COM, but fiber optic cables like singlemode fibers (OS1/OS2) , Twinax copper cables are also offered. For more information about the cost-effective fiber patch cables, Please feel free to contact us via http://www.fs.com.

Original Source: om5-fiber-cable-is-it-worthwhile-for-40g100g-swdm4-cabling-solution