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More than Circuit EngineeringFiber Optic Lines
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When using fiber-optic data
communication links, designers can develop new products which provide noise
immunity that is superior to copper wire.
Optical fibers do not require rigorous grounding rules to avoid ground loop
interference, and fiber-optic cables do not need termination resistors to avoid
reflections.
Fiber-optic links also have an intrinsically higher probability of surviving lightning strikes than copper wire alternatives.
Optical connectors suited for field termination with minimal training and simple tools are now available. For additional details refer to the HFBR-4531/4532 crimpless connector data sheet, Agilent publication number 5965-1659E.
When using plastic optical fiber (POP) or hard clad silica (HCS®) the total cost of the data communication link is roughly the same as when using copper wire.
Digital fiber-optic links are normally used to transport serial data. When the length of the data communication channel increases parallel data transfer is generally avoided due to cost and time skew issues.
Parallel-to-serial and serial-to-parallel converters are normally used to interface computers and microprocessors to fiber-optic links.
When parallel data is serialized it is usually encoded, but not all serial communication protocols make use of encoding.
Some existing copper wire serial data communication protocols use no encoding or make use of protocols that send data in bursts or packets.
Encoding merges the clock and data into one serial data communication link. Encoding eliminates time skew, which can occur when separate communication links are used for the clock and serial data.
1 bit/sek
= 1 Bd.
Fig.1. Solution for dc to 40 KBd TTL Data at Distances Between 0 and 53 meters.
Zero to 53 meter length of 1 mm DIA.
Plastic Optical Fiber when led Transmitter on State Forward Current = 10 mA.
Attributes:
1) No adjustments needed.
2) No receiver overdrive with short fiber-optic cables.
3) DS3631 costs roughly $0.25 and is available from National Semiconductor.
4) Uses lowest cost 1 mm dia. plastic optical fiber.
5) Uses Agilent's HFBR-4531 or HFBR-4532 crimpless connector which can be field terminated in less than 1 minute.
Fig. 1. Solution for dc to 40 KBd TTL Data at Distances Between 0 and 53 meters.
(Click to enlarge the circuit)
Fig.2. Solution for dc to 1 MBd TTL Data at Distances Between 0 and 10 meters.
Zero to 10 meter length of 1 mm DIA.
Plastic Optical Fiber when led on State Forward Current = 60 mA.
Attributes:
1) No adjustments needed.
2) No receiver overdrive with short fiber-optic cables.
3) DS75451 costs roughly $0.25 and is available from National Semiconductor.
4) Uses lowest cost 1 mm dia. plastic optical fiber.
5) Uses Agilent's HFBR-4531 or HFBR-4532 crimpless connector which can be field terminated in less than 1 minute.
Fig. 2. Solution for dc to 1 MBd TTL Data at Distances Between 0 and 10 meters.
(Click to enlarge the circuit)
5 MBit/sek
Fig.3.
Solution
for dc to 5 MBd TTL Data at Distances Between 0 and 1.7 kilometers.
Zero to 1.7 kilometer length of 62.5/125 mm DIA.
Glass Optical Fiber when led on State Forward Current = 48 mA
Attributes:
1) No adjustments needed.
2) No receiver overdrive with short fiber-optic cables.
3) DS75451 costs roughly $0.25 and is available from National Semiconductor.
4) Uses commonly available 62.5/125 mm DIA. glass optical fiber.
5) Uses ST or SMA optical connectors.
Fig. 3.
Solution for dc to 5 MBd TTL Data at Distances
Between 0 and 1.7 kilometers.
(Click to enlarge the circuit)
Fig.4. Solution for dc to 10 MBd TTL Data at Distances Between 0 and 300 meters.
Zero to 300 meter length of 200 mm DIA.
Hard Clad Silica (HCS) Optical Fiber at 0 to 70 Celsius when Led Transmitter on State Forward Current = 60 mA.
Attributes:
1) No adjustments needed.
2) No receiver overdrive with short fiber-optic cables.
3) DS75451 costs roughly $0.25 and is available from National Semiconductor.
4) Uses low-cost 200 mm hard clad silica (HCS) optical fiber.
5) Uses Agilent's HFBR-4521 connector which can be field terminated in less than 1 minute.
Fig. 4. Solution for dc to 10
MBd TTL Data at Distances Between 0 and 300 meters.
(Click to enlarge the circuit)
Fiber Optic Speed Lines
Fig.5.
Solution for dc to 32 MBd TTL Data at
Distances Between 0 and 1.3 kilometers.
Attributes:
1) Can be used with nnencocled data.
2) No analog circuit design needed.
3) No nrinted circuit desipn needed.
4) No adjustments needed.
5) No receiver overdrive with short fiber-optic cables.
6) Uses low-cost off-the-shelf integrated circuits from Fairchild and Linear Technology.
7) One transceiver design can be used to address a wide range of applications.
8) Can be used with 1 mm dia. POF for lowest cost, 200 mmHCS, or 62.5/125 mm multimode glass optical fibers for greater distances.
9) POF or HCS fiber connectors can be field terminated in less than 1 minute. For POF use the HFBR-4531 connector, for HCS fiber use HFBR-4521 connector.
Fig.
5. Solution for dc to 32 MBd TTL
Data at Distances Between
0 and 1.3 kilometers.
(Click to enlarge the circuit)
Table 1. Transceiver Component Values
Fig.6. Solution for dc to 32 MBd TTL Data at Distances
Between
0 and 4.0 kilometers.
Attributes:
1) Can be used with unencoded data.
2) No analog circuit design needed.
3) No printed circuit design needed.
4) No adjustments needed.
5) No receiver overdrive with short fiber-optic cables.
6) Uses low-cost off-the-shelf integrated circuits from Fairchild, Motorola, and Linear Technology.
7) One transceiver design can be used to address a wide range of applications.
8) Can be used with 1 mm dia. POF for lowest cost, 200 mm HCS, 62.5/125 mm
multimode glass or 9/125 single-mode glass optical fibers for greater distances.
9) POF or HCS fiber connectors can be field terminated in less than 1 minute.
For POF use the HFBR-4531 connector, for HCS fiber use HFBR-4521connector.
Fig. 6. Solution for dc to 32 MBd TTL
Data at Distances Between
0 and 4.0 kilometers.
(Click to enlarge the circuit)
Table 2. Transceiver Component Values
Fig.7. Solution for 2 to 70 MBd TTL
Data at Distances Between 0 and 14.0 kilometers.
Attributes:
1) Intended for applications that use encoded data.
2) No analog circuit design needed.
3) No printed circuit design needed.
4) No adjustments needed.
5) No receiver overdrive with short fiber-optic cables.
6) Uses low-cost off-the-shelf integrated circuits from Fairchild and Micro Linear.
7) One transceiver design can be used to address a wide range of applications.
8) Can be used with 1 mm dia. POF for lowest cost, 200 mm HCS, 62.5/125 mm multimode glass or 9/125 single-mode glass optical fibers for greater distances.
9) POF or HCS fiber connectors can be field terminated in less than 1 minute. For POF use the HFBR-4531 connector, for HCS fiber use HFBR-4521 connector.
Fig. 7. Solution for 2 to 70 MBd TTL
Data at Distances Between 0 and 14.0 kilometers.
(Click to enlarge the circuit)
Table 3. Transceiver Component Values
160 MBit/sek. Distances between 0 and 6 kilometers.
Fig.8. Solution for 20 to 160 MBd +5V
ECL (PECL) Data at Distances
between 0 and 6 kilometers.
Attributes:
1) Intended for applications that use encoded data.
2) Can be used with off-the-shelf physical layer chips such as the Cypress HOTLink™ to build lowcost byte-to-light protocol-independent data communication links.
3) No analog circuit design needed.
4) No printed circuit design needed.
5) No adjustments needed.
6) No receiver overdrive with short fiber-optic cables.
7) Uses low-cost off-the-shelf integrated circuits from Fairchild, Motorola, and Texas Instruments.
8) One transceiver design can be used to address a wide range of applications.
9) Can be used with 1 mm dia. POF for lowest cost, 200 mm HCS, 62.5/125 mm multimode glass or 9/125 single-mode glass optical fibers for greater distances.
10) POF or HCS fiber connectors can be field terminated in less than 1 minute. For POF use the HFBR-4531 connector, for HCS fiber use HFBR-4521 connector.
Fig. 8. Solution for 20 to 160 MBd +5V
ECL (PECL) Data at Distances
between 0 and 6 kilometers.
(Click to enlarge the circuit)
Table 4. Transceiver Component Values
Fig.9. Byte-to-light interface between PECL-compatible fiber-optic transceivers and off-the-shelf PHY chips, such as Cypress Semiconductor’s
HOTLink.
Recommended power Supply Filter and +5 V ECL
(PECL) Signal Terminations for the Cypress HOTLink.
Fig. 9. Byte-to-light Interface. 160
MBd Data at Distances
between 0 and 6 kilometers.
(Click to enlarge the circuit)
Components for Plastic
Optical Fiber
Plastic optical fiber, 1 mm in
diameter, is ideal for short link lengths and moderate data rates. The key
advantage of plastic fiber is its low
material and connectoring cost. As the diameter of the fiber core is large,
there is less variability of the optical
signal due to misalignment. The HFBR-453x series of crimpless connectors
improves this even more. The innovative design
uses a simple snap-in technique which eliminates the need for crimping. This
connector not only saves the user labor
and tool cost, but reduces the yield loss due to installation errors.
Typical applications where plastic optical fiber
is implemented are: frequency conversion; GTO and IGBT control; fieldbuses,
such as Sercos, Profibus and InterBus-S; RS-485
interfaces
Table 5.
Components for Hard Cladded Silica (HCS ®) Fiber
HCS ® fiber, 200 µm in diameter, combines the advantages of
glass fiber but at a cost close to plastic optical fiber. Its
diameter is still relatively large, which keeps connectoring costs low. Another
advantage is that the HCS ® fiber cable
is fire resistant and so, is rated for risers (UL 1666). If the cable burns due
to contact with other materials, it does not
emit toxic fumes and so is usable in plenums (UL 910).
Table 6.
Components for Glass Fiber
The glass fiber mentioned in this selection guide are multimode
fiber (62.5/125 µm). Glass fiber
with 62.5 µm core is the most common fiber used in local area network (LAN)
applications, and is ideal for
higher data rate over longer distances.
Table 7.
.
650 nm discrete optical components
selection guide
Table 8.
The following are typical parameters
for the types of fi ber:
Table 9.
added 23.07.07 19:09:09 | 
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