FO Technology, Products, News & Tips
         19 May 2010        

Fiber Optic Technology
What is SBS and Why Should You Care?
SBS is Stimulated Brillouin Scattering. I guess that clears that up, right? Probably not. In the last Olson newsletter, we discussed the fact that optical power densities in the core of an optical fiber are quite high. We also discussed some of the implications of that power density. One implication that we did not discuss is that these high power densities can cause nonlinearities. The SBS nonlinearity, as it's name implies, is caused by light scattering in the glass itself. This scattering can cause the atoms in the glass to vibrate as light passes, much as wind chimes on your porch sway and clang as the wind blows. Click on the picture below to get a simplified simulation of the effect.

As the light travels through the glass in the simulation, it impacts some of the atoms and is scattered. When a light photon hits an atom it moves it slightly. When the light level gets high enough, the atoms move in such a way that they reflect light back towards the source. That's SBS.
Fun Fact: Did you know that light could move objects? Remember the military's 1980's Star Wars program that planned to shoot down incoming missiles with lasers? The most ambitious version had light levels so high that it would actually smash the missile as though it had been hit with a giant sledgehammer! So even if the missile was covered in highly reflective material, it would still be destroyed.
SBS can be seen in optical fiber at optical power levels as low as +5dBm The SBS threshold (the lowest optical power at which the effect occurs) varies a bit at different wavelengths. It is highly affected by the optical line width. An unmodulated DFB laser may have an optical line width of 10MHz. This will trigger SBS around +5dBm. If the laser is modulated, the laser's optical line width will spread out to perhaps 1GHz or more. This raises the SBS threshold significantly.
Olson Technology, Inc. employs advanced SBS suppression in many of it's products, such as the OTOT-1000-FF, 1550nm Direct Modulated Transmitter. This raises the SBS threshold to +16dBm or more. We will announce SBS suppression to +19dBm shortly. That means you can launch those power levels into a long lengths of fiber with no fear of SBS. For more details, read Olson's Application Note on Nonlinearities.
Contact the fiber optic experts at Olson Technology to experience tomorrow's technology today.
Fiber Optic Products
NeverOff is Introduced
Olson Technology, Inc. introduces the new NeverOff  DC Standby Power Sources. AC uninterruptible power supplies (UPS) have become ubiquitous in our always-on society, maintaining power to critical computer, network and communications applications. However, to date there has not been an equivalent DC UPS that can provide similar power backup functions for critical CATV and communications elements that are typically powered by low voltage DC power. The NeverOff series can be utilized in a multitude of applications and provide long term battery standby power of up to eight hours or more depending on the model and load. Units are available from 5 Volts out to up to 18 Volts output. There are a number of available output power options with loads of up 12 Watts or more.
These units utilize the latest in battery technology and all battery packs are fully protected against over-voltage, under-voltage, as well as short circuits. Multiple connector options are available.
These units are self-contained, and all battery packs are field changeable. The rugged design of these units provides for short circuit protection as well as high-energy transient protection. All units provide constant regulated output voltage in the standby/ battery mode.
Typical applications and features include:
  • Powering drop amplifiers. Units can be customized to allow the use of the existing wall adapter.
  • Powering RFoG (RF Over Glass) or HFC (Hybrid Fiber Coax) nodes similar to the Olson OTPN-800 Series.
  • Powering Wireless devices to provide for uninterrupted VOIP (Voice Over Internet Protocol) service.

Currently two standard models are defined. The Model 101 can power a 1.5 Watt load for 8 hours or a 3 Watt load for 4 hours. The Model 201 can power a 7 Watt load for 8 hours or a 12.5 Watt load for 4 hours. Customized models can be easily produced to meet your specific requirements.

Contact the fiber optic experts at Olson Technology to experience tomorrow's technology today.

Fiber Optic News
Olson Technology's web site now has an updated 2010 Short-Form Catalog.
You will also find archived newsletters at the new and improved Olson Technology web site.
Olson Technology, Inc. and Toner, Incorporated are co-hosting a Fiber 101 Training Session at the AHECTA conference in Minneapolis on 16 June 2010. The course will cover the basics of fiber optics, discuss the key fiber optic components in great detail and cover many aspects of basic and advanced fiber optic system design.
The purpose of the AHECTA organization is to promote and develop the use of campus communication, cable, and video services as instructional, informational and entertainment tools in Higher Education.
Want to get smarter about fiber optics? Visit our ever expanding Fiber Optic Technology page on the Olson web site for a wealth of knowledge that can help you be successful working with fiber optics.
Contact the fiber optic experts at Olson Technology to experience tomorrow's technology today.
Fiber Optic Tips
APC vs UPC Optical Connectors
Perhaps the most frequent call we get from distressed customers pertains to APC and UPC or PC connectors. Let's define these terms first. APC stands for Angle Polished Connector. It is the green connector in the picture below. Note that the tip of the white ceramic has an angle on it. This angle prevents backreflections which will seriously degrade the performance of any analog fiber optic system, such as CATV and Satellite. UPC stands for Ultra-Physical Contact and PC stands for Physical Contact. The blue connector in the picture is a UPC connector. You can see that its end looks flat and at zero angle. In fact it has a slightly curves end face so that the fiber cores make contact first. UPC and PC connectors do NOT have well-controlled back reflection performance.
The phone calls that we get fall into two categories;
  1. The customer used blue UPC or PC connectors in their system and they are getting poor results. Be warned... only use UPC to UPC connections in an analog system if you like getting lots of complaints.
  2. The customer has tried to mate a green APC connector to a blue UPC connector. This usually causes terrible results and can in fact often destroys both connectors. The picture below shows what such a mating would look like. As can be seen from the photo the fiber cores will not touch. This type of damage is a non-warranty repair.
It's real simple with analog fiber optic links. Go green and you'll be a happy camper. Otherwise you will be blue when you fire up your system.
Contact the fiber optic experts at Olson Technology to experience tomorrow's technology today.

Olson Technology, Inc. Headquarters
24926 Highway 108 • Mi-Wuk Village, CA 95346
USA (800) 545-1022 • TEL (209) 586-1022 • FAX
 (209) 586-1035 • 

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