MUꢀTIPROTOCO ꢀ XFP O PTICA ꢀ TRANSCEI ꢃER
—1310 NM FOR UP TO 10 KM REACH
2
Section 1
Functional Description
The 10 Gbps 1310 nm multiprotocol XFP optical transceiver is a fully duplexed
serial electric, serial optical device with both transmit and receive functions con-
tained in a single module that provides a high-speed serial link at signaling rates
from 9.95 to 11.35 Gbps. It is designed to be compliant with Telcordia GR-253-
CORE OC-192 SR-1 for 2 km reach (SONET), ITU-T G.691 STM-64 I-64.1 for 2
kmꢀreachꢀ(SDH),ꢀIEEEꢀ802.3-2005ꢀClauseꢀ52ꢀ10GBASE-LRꢀandꢀ10GꢀBASE-LWꢀforꢀ
10 km reach (Ethernet) and 10GFC 1200-SM-LL-L for 10 km reach (Fibre Chan-
nel). The transceiver is also fully compliant with the 10 Gigabit Small Form Factor
XFP Pluggable Module MSA INF8077i Rev. 4.5. A block diagram of the 10 Gbps
1310 nm multiprotocol XFP optical transceiver is shown in Figure 1.
The 10 Gbps 1310 nm multiprotocol XFP optical transceiver locks to data without
the requirement of reference clock. The reference clock inputs have an inter-
nal 100 Ω differential line-to-line termination. It has several low-speed interface
connections, including a two-wire serial interface. These connections include
module not ready (Mod_NR), module deselect (Mod_DeSel), Interrupt, trans-
mitter disable (TX_DIS), module absent (Mod_ABS), receive loss (RX_LOS), and
power down/reset (P_Down/RST).
The XFP transceiver also supports XFI loopback. In this mode, data input on the
electrical Tx pins of the XFP module is retimed and is redirected to the Rx pins of
the module. This facilitates system-side test and debug operations.
Transmitter
The transmitter path converts serial NRZ electrical data from line rate of 9.95 to 11.35
Gbps to a standard compliant optical signal. The transmitter accepts a 100 Ω differen-
tial 120 mV peak-to-peak to 820 mV peak-to-peak 10 Gbps CML electrical signal on
TD- and TD+ pins.
Inside the module, the differential signals pass through a signal conditioner with
equalization that compensates for losses and deterministic jitter present on the input
data stream. The transmit CDR function generates a clock that is at the same fre-
quency as the incoming data bit rate of the electrical data input. The clock is phase
aligned by a phase locked loop (PLL) that samples the data in the center of the data
eye pattern. The CDR function does not require a reference clock to“lock”to incom-
ing data. The CDR contains a lock detect circuit that indicates successful locking of
the PLL onto the incoming data.
The output of the Tx signal conditioner is input to the laser driver circuit, which
transforms the small swing digital voltage to an output modulation that drives a
semi-cooled, electroabsorption (EA) modulator. The optical signal is engineered to
meet the SONET/SDH, 10 G Ethernet, 10 G Fibre Channel and corresponding for-
ward error correction (FEC) rates specifications. Closed-loop control of the trans-
mitted laser power and modulation swing over temperature and voltage variations
is provided. The laser is coupled to single-mode optical fiber through an industry-
standard LC optical connector.
