Optical Loss Test Set (OLTS)
CablesOne use Optical loss test sets incorporate a stable source and a meter. Measurements are made with a two stage process. First the source power is measured (referenced), then light is put through the device to be tested, and a second measurement is made. The difference in the measurements is the device loss.
What is an LTS best used for?
1. A pair of these units can be used to simply and reliably measure end to end loss of installed systems, preferably using a bi-directional or two-way method at multiple wavelengths, with minimum inventory and modest technician skill levels.
2. There are a wide variety of LTS, with wide differences in resulting productivity. The simplest are just a source and meter in one box. The most sophisticated perform automated bi-directional, multi-wavelength loss and return loss measurement in a few seconds.
3. LTS are fairly easy to use: in most organisations, many technical staff could perform a loss measurement.
4. Most LTS can be used to measure the absolute power of a transmitter or receiver, and some can be used as a tone transmitter or detector.
5. If the LTS measures return loss as well, the requirements for optical TDR evaluation may be eliminated in some cases.
6. Some LTS actually provide the simplest possible solution of all types, since their automation makes them less complex to use than a separate source and meter.
7. A single LTS instrument may be cheaper than a separate source and meter, and so may be a cheaper solution in some cases.
These are widely used by almost everyone involved in hands-on work, since it is the simplest way to ensure that connections are up to standard. Used during work on component manufacture, equipment manufacture, cables and transmission systems. In this role, it is used to to formally accept end to end loss specifications, and sometimes to measure return loss.
OLTS also has Limitations as below:
1. An LTS cannot identify the position of a point fault in a route that otherwise passes the end to end loss specifications. For this reason, both OTDRs and LTS are often used for acceptance verification.
2. In some situations, it is cheaper and easier to use a separate source and meter.
3. Specific instruments may have particular limitations to do with accuracy, warm up periods, battery lifetime and ease of use.
4. An LTS should have some sort of automated wavelength synchronisation for measurement at multiple wavelengths. Not all units have this useful feature.