914-X Series Bench Test - Moog FOCAL 914-HDE L1 User Manual

10.4

914-X Series Bench Test

Basic Link Operation
Basic operation of the uplink (remote to console) and downlink (console to remote) can be verified in a bench test
simply by connecting fiber jumpers between the optical transceivers. The number of jumpers and the optical
attenuation required depends on the optical configuration of the system under test. In some optical configurations,
it may be required to use 5 or 10 dB optical attenuators placed between the fiber bushings on the mux (remote)
card and the bushings on the demux (console) card to ensure the optical receivers are not saturated. Complete a
flux budget calculation for your system, referring to the optical transmit power and receive overload level to
determine whether optical attenuation is required or not.
After power is applied to the 914-HDE, the power LED D6 should be on (green). A red Link Fault LED D9 indicates
insufficient received optical power, typically due to excessive loss in the fiber link. Excessive loss may be caused
by poor fiber connections (contaminated bushings, damaged fiber, damaged ferrules) or excessive fiber bends.
CARE MUST BE TAKEN WHILE HANDLING FIBER. DO NOT TOUCH THE TIP OF THE FIBER CABLE
(FERRULE) SINCE CONTAMINATION WILL OCCOUR. ALL FIBER CONNECTIONS MUST BE INSPECTED AND
VERIFIED TO BE CLEAN PRIOR TO FINAL INSTALLATION.
If the basic optical link is present (LED D8 is on), there should be data continuity through the multiplexer system to
provide video and serial data links.
Optical Power Budget Test
1. To verify the console to remote flux budget (downlink), measure the transmit power of the console card by
connecting the optical output directly to a calibrated optical power meter using a short, low-loss, test jumper.
(Ensure the correct fiber type is used. All fibers must be of the same type. e.g. for SM normally 9 um core,
for MM 50 um or 62.5 um core)
2. Remove the test jumper and install a variable optical attenuator (VOAT) between the console and remote
cards.
3. Adjust the VOAT until the red Link LED on either one of the modules turns on, then reduce the loss to the
point where both green link LEDs are continuously on. A stable serial data connection is a good reference
point.
4. Measure the received optical power at the remote side by connecting that end of the VOAT to the optical
power meter. The difference between the transmit power previously measured and this receive measured
power is an estimate of optical power budget. A spool of fiber used with the VOAT can also be used to
simulate dispersion effects over long cable lengths.
5. Repeat steps 1-4 with connections reversed to verify the remote to console (uplink) optical budget.
Focal Technologies Corporation
A Moog Inc. Company
Model 914-X Series Modular Multiplexer System User Manual
Document Number: 914-0601-00 Rev. 5.0
Page 10-4