Design Summary:
Functional Description, Receiver Section
Design for low-cost, high-volume manufacturing
The receiver section, Figure 2, contains a 12-
Avago’s parallel optics solution combines twelve channel AlGaAs/ GaAs photodetector array,
2.7 Gbd channels into discrete transmitter and
receiver modules providing a maximum
aggregate data rate of 32 Gb/s. Moreover, these
modules employ a heat sink for thermal
management when used on high-density cards,
have excellent EMI performance, and interface
with the industry standard MTP®/MPO
connector systems. They provide the most cost-
effective high- density (Gbd per inch) solutions
for high-data capacity applications. See Figure
1 for the transmitter and Figure 2 for the
receiver block diagrams.
transimpedance preamplifier, filter, gain stages
to amplify and buffer the signal, and a
quantizer to shape the signal.
The Signal Detect function is designed to sense
the proper optical output signal on each of the
12 channels. If loss of signal is detected on an
individual channel, that channel output is
squelched.
Packaging
The flexible electronic subassembly was
designed to allow high-volume assembly and
test of the VCSEL, PIN photo diode and
supporting electronics prior to final assembly.
The HFBR-772BZ transmitter and the HFBR-
782BZ receiver modules provide very closely
spaced, high-speed parallel data channels.
Within these modules there will be some level
of cross talk between channels. The cross talk
within the modules will be exhibited as
additional data jitter or sensitivity reduction
compared to single-channel performance. Avago
Technologies’ jitter and sensitivity specifications
include cross talk penalties and thus represent
real, achievable module performance.
Regulatory Compliance
The overall equipment design into which the
parallel optics module is mounted will
determine the certification level. The module
performance is offered as a figure of merit to
assist the designer in considering their use in
the equipment design.
Organization Recognition
See the Regulatory Compliance Table for a
listing of the standards, standards associations
and testing laboratories applicable to this
product.
Functional Description, Transmitter Section
The transmitter section, Figure 1, uses a 12-
channel 850 nm VCSEL array as the optical
source and a diffractive optical lens array to
launch the beam of light into the fiber. The
package and connector system are designed to
Electrostatic Discharge (ESD)
There are two design cases in which immunity
allow repeatable coupling into standard 12-fiber to ESD damage is important.
ribbon cable. In addition, this module has been
The first case is during handling of the module
prior to mounting it on the circuit board. It is
important to use normal ESD handling
designed to be compliant with IEC 60825 Class
1 eye safety requirements.
The optical output is controlled by a custom IC, precautions for ESD sensitive devices. These
which provides proper laser drive parameters
and monitors drive current to ensure eye
safety. An EEPROM and state machine are
programmed to provide both ac and dc current
drive to the laser to ensure correct modulation,
eye diagram and extinction ratio over
variations of temperature and power supply
voltages.
precautions include using grounded wrist
straps, work benches, and floor mats in ESD
controlled areas.
The second case to consider is static discharges
to the exterior of the equipment chassis
containing the module parts. To the extent that
the MTP® (MPO) connector receptacle is
exposed to the outside of the equipment chassis
it may be subject to system level ESD test
criteria that the equipment is intended to meet.
See the Regulatory Compliance Table for further
details.
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AVAGO [ AVAGO TECHNOLOGIES LIMITED ]
