jsh-42l3ad3-5 JDS Uniphase Corporation, jsh-42l3ad3-5 Datasheet - Page 4

• Manufacturer Part Number: jsh-42l3ad3-5
• Description: Sfp Pluggable 4/2/1g Fc/gbe Fp And Dfb Transceiver Rohs 6/6 Jsh-42l3ad3-5, Jsh-42l3ad3-5g, Jsh-42l3ad3-20
• Manufacturer: JDS Uniphase Corporation

SFP PlUGGABlE 4/2/1G FC/GBE FP AND DFB TRANSCEIvER ROHS 6/6
4
Transmit Section
The input, an AC coupled differential data stream from the host, enters the AC
Modulation section of the laser driver circuitry where it modulates the output op-
tical intensity of a semiconductor laser. The DC Drive circuit incorporates an au-
tomatic power control (APC) loop which maintains the laser at the correct preset
power level. In addition, safety circuits in the DC Drive will shut off the laser, or
guarantee safe launch power if a fault is detected. The transceiver provides the AC
coupling for the +Tx/-Tx lines. No AC coupling capacitors are required on the
host card for proper operation. There are two outputs from the transmitter section
that deliver signals proportional to the average transmitted optical power and also
the laser average bias current. These signals are digitized and processed within the
transceiver for the Digital Diagnostic Monitoring feature.
Receive Section
The incoming modulated optical signal is converted to an electrical signal by the
photoreceiver. This electrical signal is then amplified and converted to a differen-
tial serial output data stream and delivered to the host. A signal strength detector
indicates whether light is present or not at the input to the photoreceiver. This
signal is provided to the host as a loss-of-signal (Rx_LOS) status line. The trans-
ceiver provides the AC coupling for the +Rx/-Rx lines. No AC coupling capacitors
are required on the host card for proper operation. There is an output from the
pre-amplifier in the photoreceiver that is proportional to the average optical power
incident on the photodiode. This signal is digitized and processed within the trans-
ceiver as part of the Digital Diagnostic Monitoring feature.
Digital Diagnostic Monitoring
The digital diagnostic monitoring feature is compliant with document SFF-8472,
“Digital Diagnostic Monitoring Interface for Optical Transceivers” [5]. In addi-
tion to transmitted optical power, laser-bias current and received optical power,
there are also sensors for transceiver temperature and supply voltage which are all
multiplexed to the analog-to-digital converter. After the signals are digitized, they
are processed and compared to alarm levels for the optional alarm features and
interrupts. The real-time values of each monitored parameter can be read and used
for evaluating the status of the link. Also, the alarm/warning bits can be used to
provide transceiver status or enable an interrupt notification. A user-writable non-
volatile RAM scratch space for customer use is limited to 100,000 write cycles.
Optional Monitor TX_FAUlT Alarm/warning Interrupt
The transceiver provides programmable Alarm/Warning Interrupt Enable bits.
They are used by the transceiver to generate a TX_FAULT signal usable as an inter-
rupt to the host for an alarm/warning condition. This is an extension to the polling
architecture of SFF-8472 and allows for interrupt driven host microcode.