Fiber Optic Test
TS LAN 500 is a five-day course that prepares crafts people for all aspects of fiber optic cable installation in a local area network environment. Both multimode and single-mode fiber types are covered. Cable placement, fusion and mechanical splicing, cable termination (connector installation and pigtail splicing) and acceptance testing are taught with extensive hands-on practice.
Corning TS-LAN-500 cheater.
(or cursor keys)- What are the two basic types of fiber?
Single-Mode, and Multi-Mode.
- The 3 parts of a fiber are (the 3 C's)?
Coating, cladding, and core.
- The North American Standard core sizes for Milti-Mode fiber are?
62.5 and 50 microns.
- The core size for Coring Single-Mode fiber is?
8.3 microns.
- The cladding size for both Single-Mode and Multi-Mode fiber is?
125 microns.
- What invention in the 1960's made fiber optics more feasible?
Lasers.
- Index of Refraction equals:
Speed of light in a Vacuum divided by speed of light in a medium.
- As the index of refraction increases, the speed of light in a medium
Decreases.
- In what portion of th fiber does light travel for fastest? Core or cladding?
Cladding.
- The principle of operation, which permits propogation of light in Single-Mode fiber, is known as
Total Internal Reflection.
- The loss of opticle power is referred to as?
Attenuation.
- What are the two types of attenuation?
Intrinsic and Extrinsic.
- Which type of attenuation is due to traits within the fiber?
Intrinsic.
- Which type of attenuation can be caused by the cable installer?
Extrinsic.
- What are the two types of extrinsic attenuation?
Macrobend and Microbend.
- What type of bending is due to tight tie wraps?
Microbend.
- What type of bending is due to exceeding the bend radius?
Macrobend.
- What is dispersion?
Spreading of signal pulses as it moves through a medium.
- What kind of dispersion can be a problem in Multi-Mode fiber?
Modal dispersion.
- What kind of dispersion affects Single-Mode fiber?
Chromatic dispersion.
- What is bandwidth?
Information carrying capacity.
- What is the bandwidth of Single-Mode fiber?
Infinite.
- What are the two optimal wavelengths used in a Multi-Mode system?
850 and 1300 nm.
- What are the two optimal wavelengths used in a Single-Mode system?
1310 and 1550 nm.
- A 3db loss in power is a...
50% power loss.
- Why is 1310 an optimum wavelength for standard Single-Mode?
There's a near zero dispersion loss @ 1310nm.
- What is the advantage of Dispersion shifted fiber?
Lower attenuation/dispersion @ 1550.
- Is the Index of Refraction of a standard Single-Mode fiber typically the same value across the core? Yes/No/Why?
Yes. Because, with a Single-Mode core, only one mode will be propagating in the fiber.
- Is the Index of Refraction of a standard Multi-Mode fiber typically the same value across the core? Yes/No/Why?
No, because of multiple modes taking multiple paths.
- Does all the light travel in the core of the fiber? Yes/No.
No.
- In a Single-Mode fiber what is the term used to describe the area that light actually travels, and whats its value?
Mode Field Diamter, and its value is 9.3 @ 1310, and 10.5 @ 1550 microns.
- Name two types of fiber optic designs?
Loose tube, and Tight Buffered, or Ribbon (3 types).
- Loose tube cable is optimised for outdoor use. How?
Free floating fibers in buffer tubes.
- Name two types of Corning Cable Systems Loose Tube cables:
Altos, and Freedom.
- What does "all dielectric" mean?
Non-conductive.
- Name two self supporting cable types?
Figure 8, and ADSS.
- What is the standard number of fibers per tube in Corning Cable Systems cable?
12.
- Where are the odd fiber tubes usually located?
Last tube after 2003, first tube before 2003.
- Tight buffered cable is optimised for which use?
For outdoor use.
- Name two types of Corning Cable Systems Tight Buffered cables:
MIC and Freedom 1.
- What is the main load bearer for Corning Cable Systems cable?
The central member, or strength member.
- List 3 functions of the central member:
Load bearing/tensile strength, anti-bucking, and protecting the bend radius.
- The minimum number of buffer tube positions in a stranded loose tube cable is? And why?
6, to maintain a round cable shape.
- The outside diameter of a tight buffered fiber is?
900 microns.
- The outside diameter of a fiber in a stranded loose tube cable is?
250 microns.
- Can I directly connectorise a 250 micron fiber?
No, its too small. You need a fanout kit.
- What are the three NEC lisitngs for indoor cable?
Plenum, Riser, and Gerneral (or hoizontal).
- Can I install a Plenum rated cable in a riser shaft?
Yes.
- Can I install a riser cable in a plenum space?
No.
- How much outdoor cable may I bring indoors before I must transition to an indoor cable?
50ft.
- What are the main placement consideration when installing fiber optic cable?
STRIP: Slack, Tension, Radius. Protect.
- List two reasons why leaving cable slack is important?
Fix mistakes, and for equipment relocation.
- What principle does the OTDR rely on to get light back to the receiver?
Back scatter.
- Give three examples of when you would use an OTDR?
Cable acceptance, post termination, trouble shooting.
- How does the OTDR determine distance?
Measuring time, knowing the index of refraction.
- If the index of refraction is entered incorrectly in the OTDR set-up menu, will the measurements be accurate? Yes/No/Why?
No, because the speed of light will be incorrectly estimated.
- Which method of measuring connector loss is more accurate, 2 point or LSA, and why?
LSA (least square average) 4pt method is more accurate.
- What is a ghost?
A no-loss artifact from a reflective event.
- What is a gainer, and what needs to be done when one is found?
Effect seen when the mode field diameter of adjacent fibers are different. Correct it with a bi-directional average.
- OTDR Diagram - describe each event.
A. Launch bag connector bay / B. Mechanical splice/angle connector pair / C. Fusion Splice, or bend / D. Gainer / E. Connector pair / F. Cable-end / G. Length of launch bag.
- When measuring the fiber length using an OTDR, will the fiber length be the same as the sheath length on a standard loose tube cable? Yes/No/Why?
No. SZ stranding causes extra fiber length (allowing extra length for weather expansion/contraction.
- Explain why a mechanical splice may appear as a spike on the OTDR trace and a fusion splice will not?
A mechanical splice is a break causing reflection.
- What is the name of the process that consists of alligning and fusing the ends of two fibers together?
Fusion Splicing.
- The two methods of alligning and estimating fusion splices are? Which is used for Single Mode and why?
LPAS and PAS (or CDS and V-groove). Any can be used with Single Mode, but LID is best.
- Can you use LID on a 900um fiber?
No, 250um coating only.
- What are the most critical issues in fusion splicing?
Core allignment, cleaning, cleaving.
- What are some critical steps in achieving a good cleave?
Scoring, bending, tension.
- Can you use a snap cleave to splice?
Yes, for mechanical splicing - but not for fusion.
- What should you do if a fiber breaks under a clamp pad while cleaving?
Clean the cleaver pads, and re-cleave.
- What are the differences between OS ONE and M90e fusion splicers?
OS ONE has handlers, V-Groove. M90e uses LPAS, CDS, LID.
- What are the different ways to terminate a fiber?
Factory, field, pigtail.
- What are the critical steps in Unicam instalation?
Cleave, clean, cam, crimp.
- What are the two steps involved with properly cleaning a fiber optic connector?
Wet wipe, then dry wipe. Use 90% alcohol, and lint free wipes.
- What are the two types of optical field tests?
OTDR and Attenuation tests (continuity test also).
- What information do you need to calculate the loss budget for a fiber optic system with patch panels on each end of the system?
Fiber length, number of splices, number of connectors, and wavelength.
- List the equation for figuring the number of jumpers to reference?
#RJ = 3-#patch-panels.
- What is the most common jumper reference scenario and why?
Single jumper, as mostly two patch panels.