Application Information
The Applications Engineering
group is available to assist you
with the technical under-
standing and design trade-offs
associated with these trans-
ceivers. You can contact them
through your Agilent sales
representative.
The following information is
provided to answer some of the
most common questions about
the use of these parts.
Transceiver Optical Power Budget
versus Link Length
Optical Power Budget (OPB) is
the available optical power for a
fiber optic link to accommodate
fiber cable losses plus losses due
to in-line connectors, splices,
optical switches, and to provide
margin for link aging and
unplanned losses due to cable
plant reconfiguration or repair.
Figure 4 illustrates the predicted
OPB associated with the
transceiver specified in this data
sheet at the Beginning of Life
(BOL). These curves represent
the attenuation and chromatic
plus modal dispersion losses
associated with the 62.5/125 µm
and 50/125 µm fiber cables only.
12
HFBR-5905, 62.5/125 µm
10
OPTICAL POWER BUDGET (dB)
The area under the curves
represents the remaining OPB at
any link length, which is
available for overcoming non-
fiber cable related losses.
Agilent LED technology has
produced 1300 nm LED devices
with lower aging characteristics
than normally associated with
these technologies in the
industry. The industry conven-
tion is 1.5 dB aging for 1300 nm
LEDs. The
1300 nm Agilent LEDs are
specified to experience less than
1 dB of aging over normal com-
mercial equipment mission life
periods. Contact your Agilent
sales representative for
additional details.
Figure 4 was generated for the
1300 nm transceivers with a
Agilent fiber optic link model
containing the current industry
conventions for fiber cable
specifications and the draft
ANSI T1E1.2. These optical
parameters are reflected in the
guaranteed performance of the
transceiver specifications in this
data sheet. This same model has
been used extensively in the
ANSI and IEEE committees,
including the ANSI T1E1.2
committee, to establish the
optical performance
requirements for various fiber
optic interface standards. The
cable parameters used come
from the ISO/IEC JTC1/SC
25/WG3 Generic Cabling for
Customer Premises per DIS
11801 document and the EIA/
TIA-568-A Commercial Building
Telecommunications Cabling
Standard per SP-2840.
Transceiver Signaling Operating
Rate Range and BER Performance
For purposes of definition, the
symbol (Baud) rate, also called
signaling rate, is the reciprocal
of the symbol time. Data rate
(bits/sec) is the symbol rate
divided by the encoding factor
used to encode the data
(symbols/bit).
When used in 155 Mb/s SONET
OC-3 applications the perform-
ance of the 1300 nm trans-
ceivers, HFBR-5905 is
guaranteed to the full conditions
listed in product specification
tables.
The transceivers may be used
for other applications at signal-
ing rates different than 155 Mb/s
with some variation in the link
optical power budget. Figure 5
gives an indication of the typical
performance of these products
at different rates.
2.5
TRANSCEIVER RELATIVE POWER BUDGET
AT CONSTANT BER (dB)
2
1.5
1
0.5
0
-0.5
-1
0
25
50
75
100
125
150
175
200
SIGNAL RATE (MBd)
CONDITIONS:
1. PRBS 2
7
-1
2. DATA SAMPLED AT CENTER OF DATA SYMBOL.
3. BER = 10
-6
4. T
A
= +25 C
5. V
CC
= 3.3 V dc
6. INPUT OPTICAL RISE/FALL TIMES = 1.0/2.1 ns.
Figure 5. Transceiver Relative Optical Power
Budget at Constant BER vs. Signaling Rate.
8
HFBR-5905
50/125 µm
6
4
2
0.
3
These transceivers can also be
used for applications which
require different Bit Error Rate
(BER) performance. Figure 6
illustrates the typical trade-off
between link BER and the
receivers input optical power
level.
0
0.5
1.0
1.5
2.0
2.5
FIBER OPTIC CABLE LENGTH (km)
Figure 4. Typical Optical Power Budget at BOL
versus Fiber Optic Cable Length.
5
HP [ AGILENT(HEWLETT-PACKARD) ]
