GAOTek SFP BIDI Transceiver SFPBD-121, 3.072Gb/s and 40km

This 3.072Gb/s 1310nm and 1550nm Bidirectional Small form-factor pluggable (SFP BIDI) Transceiver is used with Single-mode optical fiber to reach up to 24.85 miles (40km) transmission distance.


Key Features:

  • Up to 24.85 miles (40km) transmission distance.
  • 1310nm DFB laser and PIN receiver.
  • 1550nm DFB laser and PIN receiver.
  • Up to 3.072Gb/s data links.
  • Unique enhanced digital diagnostic monitoring interface.
  • BIDI LC/UPC type pluggable optical interface.
  • Hot-pluggable SFP footprint.
  • Metal enclosure, for lower EMI.
  • Single +3.3V power supply
  • Compliant with SFF-8472
  • Low power dissipation
  • Commercial case operating temperature range: 32°F to 158°F (0°C to +70°C)
  • Extended case operating temperature range: 14°F to 176°F (-10°C to +80°C)
  • Industrial case operating temperature range: -40°F to 185°F (-40°C to +85°C)



Technical Specifications:

Protocol2-Wire Serial Communication Protocol
Working RangeUp to 24.85 miles (40km)
Memory256-byte memory map in EEPROM
StandardsSFF-8472 and SFP MSA.

Class 1 laser safety with G.959

RoHS compliant.

Data rate3.072Gb/s
Wavelength1310nm and 1550nm
Fiber Optic Cable9/125µm Single-mode
Digital Diagnostics MonitoringEnabled
Transmitter output optical Power-2 dBm to 3 dBm
Receiver Sensitivity-19 dBm
Receiver Input Saturation Power-3 dBm
Supply Voltage3.3V
Transmitter Differential Line Input Impedance100Ω
Dimensions2.3in x 0.54in x 0.33in (L 58.4mm x W13.7mm x   H 8.5mm)
Relative Humidity5% to 95% Non-condensing

5% to 70% (Recommended)

Storage Temperature-40 °F to 185 °F (-40°C to 85°C)

Case Operating Temperature

Commercial32°F to 158°F (0°C to +70°C)
Extended14°F to 176°F (-10°C to +80°C)
Industrial-40°F to 185°F (-40°C to +85°C)




Ideal to be used on applications such as

  • Router/Server Interface
  • Other Optical Links
  • Gigabit Ethernet
  • Switched Backplane Applications
  • Switch to Switch Interface

Ordering Information:

Product IDData rate(GB/s)MediaWavelengthTransmission DistanceTemperature RangeSupply Current


3.072Single-mode fiber1310nm/1490nm


24.85 miles (40km)Commercial

32°F to 158°F

(0°C to +70°C)

280 mA


3.072Single-mode fiber1310nm/1490nm


24.85 miles (40km)Extended

14°F to 176°F

(-10°C to +80°C)


280 mA


3.072Single-mode fiber1310nm/1490nm


24.85 miles (40km)Industrial

-40°F to 185°F

(-40°C to +85°C)


280 mA

Digital Diagnostics Functions:

  • GAOTek GAO-SFPBD-121 series transceivers support the 2-wire serial communication protocol as defined in the SFP MSA1. It is very closely related to the E2PROM defined in the GBIC standard, with the same electrical specifications.
  • Additionally, GAOTek SFP Transceivers provide a unique enhanced digital diagnostic monitoring interface which allows real-time access to device operating parameters such as transmitter optical power, receiver optical power, transceiver temperature, transceiver supply voltage and laser bias current. It defines an alarm system and warning flags, which alerts the end users when particular operating parameters are outside of a factory set normal range.
  • Standard SFP Serial id provides access to identification information that describes the transceiver’s capabilities, standard interfaces, manufacturer and other information.
  • SFP MSA defines a 256-byte memory map in EEPROM that is accessible over a 2 wire serial interface at the 8 bit address 1010000X (A0h). The interface is identical to, and is thus fully backward compatible with both the GBIC Specification and the SFP Multi Source Agreement.
  • The operating and diagnostics information is monitored and reported by a Digital Diagnostics Transceiver Controller (DDTC) inside the transceiver, which is accessed through a 2-wire serial interface. The memories are organized as a series of 8-bit data words that can be addressed individually or sequentially.
  • Digital diagnostics for the GAO-SFPBD-121 are internally calibrated by default.

Electrical Interface Characteristics:

Total Supply CurrentICCAmA1
Transmitter Disable Input-HighVDISH2Vcc+0.3V
Transmitter Disable Input-LowVDISL00.8V
Transmitter Fault Input-HighVTxFH2Vcc+0.3V
Transmitter Fault Input-LowVTxFL00.8V 
Total Supply CurrentIccBmA1
LOSS Output Voltage-HighVLOSH2Vcc+0.3V 


LOSS Output Voltage-LowVLOSL00.8V


  1. A (TX) + B (RX) = 280mA (Not include termination circuit)

Optical Characteristics:

Specification of Transmitter:

Average Output PowerPOUT-23dBm
Center WavelengthλC127013101360nmGAOTEK-SFPBD-121


Side Mode Suppression RatioSMSR30dB
Spectrum Bandwidth(RMS)σ1nm
Optical Extinction RatioER9dB
Transmitter OFF Output PowerPOff-45dBm
Jitter P-PtJ0.1UI1
Output Eye MaskCompliant with G.959(class 1 laser safety)2
Differential Line Input ImpedanceRIN90100110Ohm


  1. Measured at 2^23-1 NRZ PRBS pattern
  2. Transmitter eye mask definition

Specification of Receiver:

Receiver SensitivityPIN-19dBm1
Input Optical WavelengthλIN153015501570nmGAOTEK-SFPBD-121


Input Saturation Power (Overload)Psat-3dBm
LOS AssertPA-35dBm
LOS De -AssertPD-20dBm2
LOS HysteresisPA – PD0.526dB


  1. Measured with Light source 1550nm (1310nm), ER=9dB; BER =10 -12 @PRBS=223-1
  2. When LOS de-asserted, the RX data+/- output is signal output.

Pin out of Connector Block on Host Board:

PIN Descriptions:

PinSymbol Name/DescriptionNote
1VEETTransmitter Ground (Common with Receiver Ground)1
2TFaultTransmitter Fault
3TDisTransmitter Disable.2
4MOD_DEF(2)Module Definition 2. Data line for Serial ID.3
5MOD_DEF(1)Module Definition 1. Clock line for Serial ID.3
6MOD_DEF(0)Module Definition 0. Grounded within the module.3
7Rate SelectNo connection required4
8LOSLoss of Signal indication. Logic 0 indicates normal operation5
9VEERReceiver Ground (Common with Transmitter Ground)1
10VEERReceiver Ground (Common with Transmitter Ground)1
11VEERReceiver Ground (Common with Transmitter Ground)1
12RD-Receiver Inverted DATA out. AC coupled
13RD+Receiver Non-inverted DATA out. AC coupled
14VEERReceiver Ground (Common with transmitter Ground)1
15VCCRReceiver power Supply
16VCCTTransmitter Power supply
17VEETTransmitter Ground (Common with receiver Ground)1
18TD+Transmitter Non-Inverted DATA in. AC Coupled.
19TD-Transmitter Inverted DATA in.AC Coupled.
20VEETTransmitter Ground1


  1. Circuit ground is internally isolated from ground.
  2. Laser output disabled when it is open or TDis > 2.0V, enabled on TDis < 0.8V.
  3. Should be pulled up with 4.7kΩ to 10kΩ on host board to a voltage between 2.0V and 3.6V.MOD_DEF (0) pulls the line low to indicate the module is plugged in.
  4. This is an optional input used to control the receiver bandwidth for compatibility with multiple data rates (most likely Fiber Channel 1x and 2x Rates).If implemented, the input will be internally pulled down with > 30kΩ resistor. The input states are:
  • Low (0 – 0.8V) : Reduced Bandwidth
  • (>0.8, < 2.0V) : Undefined
  • High (2.0 – 3.465V) : Full Bandwidth
  • Open : Reduced Bandwidth
  1. Loss of signal is open collector output.
  • It should be pulled up with 4.7 kΩ to 10 kΩ on host board to a voltage between 2.0V and 3.46V.
  • Logic 0 indicates normal operation.
  • Logic 1 indicates loss of signal.

Mechanical Dimensions:

Recommend Circuit Schematic:

Regulatory Compliance:

Laser Eye SafetyFDA 21CFR 1040.10, 1040.11 IEC/EN 60825-1,2Class 1 laser product
Component RecognitionIEC/EN 60950, ULCompatible with standards
ROHS2002/95/ECCompatible with standards
Electrostatic discharge(ESD)IEC/EN 61000-4-2Compatible with standards
EMCEN61000-3Compatible with standards
Electromagnetic Interference(EMI)FCC Part 15 Class B EN 55022 Class B (CISPR 22A)Compatible with standards


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