Model 914-X Series Modular Multiplexer System User Manual
Focal Technologies Corporation
Page 4-8
A Moog Inc. Company
Document Number: 914-0601-00
Rev.
5.0
4.8
914-HDE Optics
An SFP or SFP+ transceiver provides the optical interface for the 914-HDE. Many options exist including:
Singlemode or multimode fiber
Bi-directional 1310/1550 nm transceivers (L1 and M1 versions)
Bi-directional 1270/1330 nm transceivers (H1 version)
CWDM wavelengths (L1, M1 or H1 versions)
Non-standard optical budgets
Due to the high data rates, singlemode fiber is standard. Multimode fiber is only suitable for very short links (<
300m). Contact Moog Focal for multimode options. Typical link budgets for single mode fiber are 20dB for bi-
directional single fiber or 24dB for dual fiber CWDM. Moog Focal has compatible CWDM modules that can be
mounted and stacked with 914-HDE systems. Please refer to section 8.0.
4.8.1 914-HDE Flux Budget Calculation
When specifying an optical system, it is important to analyze system losses and fiber link distances in order to
calculate the required optical configuration. The following table shows a sample flux budget calculation for a system
with multiple ST bushings, a 10 km singlemode fiber link and a FORJ. Actual losses can vary widely from this, each
system flux budget calculation must use data based on actual parts in use.
Table 4-9: Sample Flux Budget Calculation
Component
Uplink (1310 nm)
Downlink (1550 nm)
Unit
Typical Output Power
-1.0
-1.0
dBm
Connector
0.3
0.3
dB
Connector
0.3
0.3
dB
Fiber Optic Rotary Joint
4.0
4.0
dB
Connector
0.3
0.3
dB
Connector
0.3
0.3
dB
Cable (for 10 km SMF length)
4.0
3.0
dB
Connector
0.3
0.3
dB
Connector
0.3
0.3
dB
Total Losses
9.8
8.8
dB
Received Power
-10.8
(=-1.0 dBm - 9.8 dB)
-9.8
(=-1.0 dBm - 8.8 dB)
dBm
Dispersion Penalty
1.0
1.0
dB
Required Receive Sensitivity
-11.8
-10.8
dBm
Typical Receive Sensitivity
-21.0
-21.0
dBm
Available Margin
9.2
10.2
dB
Assumptions:
Fiber Loss
0.4 dB/km @ 1310 nm; 0.3 dB/km @1550 nm (single mode fiber - SMF).
Connector (ST/PC)
0.3 dB/conn
FORJ Loss (Max.)
4.0 dB
4.8.2 Optical Safety
All lasers used in the 914-HDE system are Class I laser devices per IEC-60825 unless otherwise specified in
installation or configuration drawing. No special control measures or warning labels are required, although any
needless exposure of the eye should be avoided as a matter of good practice, and
fibers should never be viewed
with magnifying instruments, e.g. fiber scopes, while optical power is present.
Note that the optical
wavelengths are in the infrared range, so not visible, but magnifying instruments can still cause damaging levels to
the eye.