GAOTek SFP Transceiver with 4.25Gb/s (≤2km)

This 4.25Gb/s 850nm SFP (Small form-factor pluggable) Transceiver is used with multi-mode optical fiber to reach up to 1.24 miles (≤2km) transmission distance.




This 4.25Gb/s 850nm SFP (Small form-factor pluggable) Transceiver is used with multi-mode optical fiber to reach up to 1.24 miles (≤2km) transmission distance. It also has a VSCEL (vertical-cavity surface-emitting laser) type transmitter, PIN type receiver, an LD (Laser Driver), a limiting amplifier and digital diagnostic monitor. It is compatible with 1x, 2x, 4x Fiber Channel with data rates 1.06Gb/s, 2.125Gb/s and 4.25Gb/s. This SFP Transceiver is a Class 1 laser safety product which complies with US FDA regulations, SFF-8472 and RoHS standards.

Key Features:

  • Up to 1.24 miles (≤2km) transmission distance.
  • Up to 4.25Gb/s data links.
  • 850nm VSCEL transmitter and PIN Photo-detector.
  • Unique enhanced digital diagnostic monitoring interface.
  • Duplex LC connector.
  • Electrical interface compliant to SFF-8431
  • Metal enclosure, for lower EMI.
  • Single +3.3V power supply
  • Compliant with SFF-8472
  • 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 1.24 miles (≤2km)
Memory256-byte memory map in EEPROM
StandardsSFF-8472, SFF-8431 and SFP MSA.

1x,2x,4x FC

Class 1 laser safety

RoHS compliant.

Data rate4.25Gb/s
Fiber Optic Cable50/125um multi-mode
Digital Diagnostics MonitoringEnabled
Transmitter output optical Power-9 dBm to -2.5 dBm
Receiver SensitivityData rate at 1.06Gb/s-20 dBm
Data rate at 2.125Gb/s-18 dBm
Data rate at 4.25Gb/s-16 dBm
Receiver Input Saturation Power0 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)


Additional Information:


Ideal to be used on applications such as

  • 4xFC at 4.25Gbps
  • 2xFC at 2.125 Gbps
  • 1xFC at 1.0625Gbps
  • 1000 Base-LX Ethernet

Ordering Information:

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


4.25Multi-mode fiber850nm1.24 miles (≤2km)Commercial

32°F to 158°F

(0°C to +70°C)

330 mA


4.25Multi -mode fiber850nm1.24 miles (≤2km)Extended

14°F to 176°F

(-10°C to +80°C)


330 mA


4.25Multi -mode fiber850nm1.24 miles (≤2km)Industrial

-40°F to 185°F

(-40°C to +85°C)


330 mA

Digital Diagnostics Functions:

  • GAOTek GAO-SFP-115 transceiver support the 2-wire serial communication protocol as defined in the SFP MSA1.
  • 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 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

Electrical interface characteristics:

Input Differential ImpedanceRin1001
Single ended data input swingVin, pp180600mV
Transmit Disable VoltageVDVcc–1.3VccV
Transmit Enable VoltageVENVeeVee+ 0.8V2
Transmit Disable Assert Time10us
Differential data output swingVout,pp300850mV3
Data output rise timetr28ps4
Data output fall timetf28ps4
LOS FaultVLOS faultVcc–1.3VccHOSTV5
LOS NormalVLOS normVeeVee+0.8V5
Power Supply RejectionPSR100mVpp6


  1. Connected directly to TX data input pins. AC coupled thereafter.
  2. Or open circuit.
  3. Into 100 ohms differential termination.
  4. 20 – 80 % Measured with Module Compliance Test Board and OMA test pattern.
  5. Loss of Signal is LVTTL.
  • Logic 0 indicates normal operation.
  • Logic 1 indicates no signal detected.
  1. Receiver sensitivity is compliant with power supply sinusoidal modulation of 20 Hz to 1.5 MHz up to specified value applied through the recommended power supply filtering network.

Optical Characteristics:

Output Optical  PowerPOUT-9-2.5dBm
Optical Wavelengthλ840850860nm
Optical Extinction RatioER6dB
RMS Spectral Widthσ0.85nm
Transmitter Jitter(peak to peak)FC-PI-4 requirements
Receiver Sensitivity @ 1.06Gb/sRSENS1– 20.0dBm
Receiver Sensitivity @ 2.125Gb/sRSENS2– 18.0dBm
Receiver Sensitivity @ 4.25Gb/sRSENS3– 16.0dBm1
Wavelength RangeλC840860nm1
Input Saturation Power (Overload)Psat0dBm1
LOS AssertLOSA-30dBm
LOS De -AssertLOSD-17dBm
LOS Hysteresis0.51.0dB


  1. With worst-case extinction ratio. Measured with a PRBS 27-1 test pattern, BER<10-12

Pin out of Connector Block on Host Board:

PIN Descriptions:

PinSymbol Name/DescriptionNote
1VEETTransmitter Ground (Common with Receiver Ground)1
2TFaultTransmitter Fault2
3TDisTransmitter Disable.3
4SDA2-wire Serial Interface Data Line4
5SCL2-wire Serial Interface Clock Line4
6MOD_ABSModule Absent. Grounded within the module5
7RS0Rate Select.

Open or Low = Module supports 1.25 Gb/s

High = Module supports 4.25 Gb/s



8LOSLoss of Signal indication. Logic 0 indicates normal operation7
9RS1No connection required1
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. TFault is an open collector or drain output.
  • It should be pulled up with a 4.7k -10k ohms resistor on the host board if intended for use.
  • Pull up voltage should be between 2.0V to Vcc +0.3V.
  • High output indicates a transmitter fault caused by either the TX bias current or the TX output power exceeding the preset alarm thresholds.
  • Low output indicates normal operation. In the low state output is pulled to <0.8V
  1. Laser output disabled when it is open or TDis > 2.0V, enabled on TDis < 0.8V.
  2. Should be pulled up with 4.7kΩ to 10kΩ on host board to a voltage between 2.0V and 3.6V.
  3. MOD_ABS pulls the line low to indicate the module is plugged in.
  4. Transceiver data rate is selected through the 2- wire bus in accordance with SFF-8472.
  • RS0 is set at Bit3, Byte 110, and Address A2h.
  • Default state of RS0 is LOW (‘0’) and the state is reset following a power cycle.
  • HIGH (‘1’) selects the maximum data rate operation.
  • Transceiver data rate is selected using the Logic OR operation. Either the RS0 Pin or RS0 bit is high then the selected rate is 4.25 Gb/s.
  1. Loss of signal is LVTTL.
  • 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:


Host – Transceiver Interface Block Diagram:

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