Overview

• Individual Line Card Client Side interfaces
• Individual Card Network Side interfaces
• Individual Lightpath performance margins

You can also use the OST-ST to measure the path penalty of transmitters through various lengths and types of fiber the transmitter may encounter when deployed. 

The OST-ST can be the heart of your optical test system - automating strings of tests with IntelliScriptT, controlling external instruments such as digital sampling oscilloscopes, power supplies, environmental chambers and optical spectrum analyzers, using your own golden transmitters as clean or degraded real-world signal generators, integrating your own golden receivers into the test system, and functioning as an automated debug station.  The OST-ST is Circadiant's top-of-the-line Optical Standards Tester and its prodigious test capabilities - including extensive real-world testing - lets you know more about your DUT's problems and performance, in less time, than you ever thought possible.

The OST-ST automatically generates factory calibrated real-world SRS test signals at the 9.9 Gb/s and 10.3 Gb/s 10 GigE LAN/WAN rates, and the 10.5 Gb/s INCITS 10 Gigabit Fibre Channel standard rate. The OST-ST also generates signals at the ITU G.709 OTN 10.7 Gb/s rate. 

OSTs are the de facto industry standard for SRS testing which means your test results will correlate with others performing SRS tests all over the world.  Additionally, the built-in process control enables you to keep getting the same SRS test results.   There are no complicated recipes to follow in order to generate the difficult to construct and hard to calibrate SRS test signal, just choose the variety of SRS signal you want from the graphical user interface and press start.

The OST-ST automatically performs SRS, sensitivity, overload, path penalty, BER vs. OSNR and IsoBER tests using standards-defined SRS signals, variably degraded real-world signals or clean signals with PRBS patterns. The available OST-ST protocol option also provides you with the ability to conduct tests using 10 GigE LAN and WAN traffic, SONET, SDH, PoS, and OTN traffic.  The OST-ST displays a simple PASS or FAIL result at the conclusion of a test - based on criteria you set - either exactly to one of the standards or to your own specification. 

Features

All the functionality needed to conduct SRS, sensitivity, overload, BER vs. OSNR and IsoBER and transmitter output power tests are included in the OST-ST including fiber amplifier, optical power meters, optical switches, attenuators, frequency synthesizers, clock sources, PRBS test pattern generator, stress conditioner, E/O and O/E converters, 4th order Bessel-Thomson filter, sinusoidal amplitude interferer, jittered clock sources, and BERT. Path penalty tests utilize your own spools fiber for meaningful results.  Protocol generators and analyzers are also included in the OST-ST when you order the protocol option.  Furthermore, tests are automated, with SRS, sensitivity, overload, path penalty and BER vs. OSNR test results conveniently displayed on-screen for you with Circadiant's Straight-Line BER Plot that makes it easy to see if a DUT has abnormal behavior like an error floor.  At the end of a test, you'll have all the information you need to PASS or FAIL a DUT against an SRS standard, or against your own specifications.

The OST-ST tests 1310 nm and 1550 nm single mode DUTs to the -LR and -ER SRS standards and with the optional A3318 850 nm/Electrical Interface, the OST-ST also tests 850 nm multi-mode DUTs to the -SR standards.

Use the OST-ST to test Ethernet, SONET, SDH, OTN, or PoS systems and line cards, and components including XFP, X2, and Xenpac transceivers, 300-pin transponders, ROSAs, eye-opening chips, TIAs, SERDES chips, PINs, APDs, and receivers with clean or real-world signals.

In addition to using real-world test signals, you can use non-degraded test signals when making sensitivity and overload tests.  The Circadiant Straight-Line BER plot displays measured BER levels versus a range of optical powers or optical modulation amplitudes, and fits lines to the data points. The OST-ST will either automatically select the optical power ranges for you, or you can select the range yourself - anywhere from -40 dBm to 0 dBm.  Obtaining sensitivity measurements at exact BER levels with the OST-SRS is simple.  Sensitivity is automatically interpolated between measured data points, or extrapolated beyond measured data points.  This means quoting performance at the SRS 10-12 BER level is as simple as reading the value off of the display or forwarding supported Excel files.  With the OST-ST, there's no need for you to use Mathcad type software to interpret test results - all the analysis is conducted with Circadiant's powerful suite of statistical algorithms. 

The automated overload test included in the OST-ST is similar to a sensitivity test, but is conducted with high-power signals rather than low-power signals.  Systems, modules and components that are operated back-to-back should have their high-power BER performance measured to ensure there is no sudden rise in the BER rate at levels that may be experienced in the field.  The OST-ST performs overload tests up to +8 dBm.  The real-world SRS signal may also be used when running an overload test to measure full operating range compliance of DUTs to the IEEE 802.3ae and the INCITS 10GFC standards. 

The Path Penalty test allows you to check the quality of a DUT's transmitter by measuring the difference in optical power needed to reach a given BER between a short length of fiber and a long length of fiber. Typically, more optical power is needed on an RX after passing through a long length of fiber to reach satisfactory BERs. Chromatic dispersion, reflections, scattering, components and other degradations contribute to an overall penalty of a signal passing through a network. The OST-ST does not include a long length of fiber. Instead, the OST-ST has a Path In and a Path Out connector to include your spool of fiber and any other network components such as EDFAs, Dispersion Compensation Fiber, optical switches, or patch panels in the long path. The A3308 first makes a sensitivity measurement going through the short path. Then an internal optical switch in the A3308 automatically activates to include the fiber and components attached to the Path In and Path Out connectors. Another sensitivity measurement is made and the difference in dB between the BER of the long and short path is calculated and displayed as the path penalty measurement result.

The OST-ST's IsoBER test acts like an oscilloscope eye-mask test, but instead of using waveform samples, the OST-ST finds and plots combinations of OSNR and optical power that produce the same BER level.   This test is helpful in determining the operating ranges of long-haul telecommunication systems -- from high optical power with excellent OSNR to low optical power with poor OSNR and points in-between.  You define the mask and if any of the plotted points fall in the masked area, the DUT is classified as FAIL.  As long as all the plotted points stay outside the mask - indicating good performance - the DUT is classified as a PASS.  By hand, making IsoBER tests can take the better part of a day.  With the OST-ST, you'll have results in minutes.

The automated transmitter output power test included in the OST-ST measures the optical power level of a transmitter and compares it to a defined acceptable range.  If the transmitter's optical power level is within the specified range, the test returns a PASS.  If there is too much optical power, or not enough optical power, the test returns a FAIL. 

You may also use the OST-ST to control other test equipment such as digital sampling oscilloscopes, optical spectrum analyzers, optical switches, wavelength meters, power supplies and temperature chambers.  This allows you, for example, to run the same SRS test over and over, but with the DUT at different combinations of temperature and voltage so you will be sure your DUT meets the SRS standard over all its operating ranges.

The OST-ST includes the IntelliScriptT mode -- a very powerful productivity enhancer. IntelliScriptT allows you to define an automated sequence of tests using a simple point-and-click interface. Any of the built-in tests can be included, all using your own defined test parameters. Use IntelliScriptT in a development lab to run a complete suite of diagnostic tests over the course of many hours. You simply initiate the test series and return at your leisure to collect the results. Use IntelliScriptT in manufacturing for efficient pass/fail testing with automatic report generation.

The OST-ST includes an application that lets you operate the OST-ST as a debug station.  A sequence of tests are conducted on a DUT using both the OST-ST's suite of tests, and tests based on external devices controlled via GPIB.  The test flow is set up so that basic failures are tested before attempting to check for more subtle problems. For example achieving sync is tested before trying to measure sensitivity. A "stop-on-fail" feature allows the test sequence to be cut short on the first failure to avoid wasting time on further tests.

Instead of dealing with complicated equipment setups, time-consuming equipment calibrations, complex SRS signal compounds, iterative equipment programming, correctly applying fiber optic test theory, and manipulating BER probability statistics - the OST-ST does it all for you.  With an OST-ST you'll be making fast, consistent and correlated SRS, sensitivity, overload and transmitter output power measurements in no time.and you'll have confidence that your systems, line cards, modules and components will work when deployed because you'll have already tested them with real-world signals.

Specifications

Stressed Receiver Sensitivity

The 10 GigE LAN and WAN specification requires receivers to be tested using an optical signal that has both horizontal and vertical jitter, a poor extinction ratio and slow rise and fall times:	The OST provides test signals with factory calibrated degradations and sweeps over the jitter mask of 40 kHz to 10 times the loop bandwidth without the need for complex calibration procedures.
To configure a test, simply select the 10G BASE-L or 10G BASE-E test from the menu. When used with the A3318 850nm/Electrical OST Interface, 10G BASE-S may be selected. To perform FibreChannel SRS tests, the clock rate is set to 10.5 Gb/s

Automated Tests

• Sensitivity - Plots and computes BER vs. Optical Power or BER vs. OMA with PRBS (or optional protocols) using integrated optical power meters, attenuators, splitters, filters,
  etc...
• Overload - Plots and computes BER vs. Optical Power or BER vs. OMA up to +8 dBm.
  
• Path Penalty (Dispersion Penalty) - Determines the difference in sensitivity through a short and long length of fiber.
  
• BER vs. OSNR - Plots and computes BER vs. Optical Signal to Noise Ratio at the same optical power level.
  
• Optical Power vs. OSNR - Combinations of Optical Signal to Noise Ratio and Optical Power that produce the same BER.
  
• TX Power - Verifies the transmitter Device Under Test is within the specified range.
  
• Internal Sensitivity - Uses the OST's internal receiver as a reference receiver to measure the performance of transmitters.

Straight Line BER

The OST plots test results on screen using a special scale that for well-behaved DUTs will have a linear plot of BER vs. average optical power or BER vs. OMA. This feature makes it easy to see if there are any problems with the DUT such as an error floor.

Protocol Capabilty (Optional)

Create 1 GigE, 10 GigE LAN/WAN, 10 Gb/s SONET/SDH, or 10.7 Gb/s OTN traffic to more thoroughly test devices and systems
in a real-world environment.

Optical Ports

• Monitor Port - Taps either the transmitted or the received signal for output to an external device, such as an oscilloscope or an OSA.
  
• Reference Transmitter Ports - These ports are activated only on the OST-ST.
• To DUT Port - The main output connector that connects to a DUT.
  
• From DUT Port - The main input connector that accepts a signal from a DUT.
  
• Reference Receiver Ports - These ports are activated only on the OST-ST.
  
• Path Ports - These ports connect to your spool of fiber and are used in manual Path Penalty tests.

Signal Output

• Clock Rate - 1.25 Gb/s (Optional), 9.9 Gb/s, 10.3 Gb/s, 10.5 Gb/s, 10.7 Gb/s
  
• PRBS - 2^7-1, 2^15-1, 2^23-1, 2^31-1

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To find out more about Circadiant products call Phoenix Datacom on 01296 397711, email info@phoenixdatacom.comor use the Request More Info form.