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:

Protocol 2-Wire Serial communication Protocol
Working Range Up to 1.24 miles (≤2km)
Memory 256-byte memory map in EEPROM
Standards SFF-8472, SFF-8431 and SFP MSA.

1x,2x,4x FC

Class 1 laser safety

RoHS compliant.

Data rate 4.25Gb/s
Wavelength 850nm
Fiber Optic Cable 50/125um multi-mode
Transmitter VSCEL
Receiver PIN
Connector LC
Digital Diagnostics Monitoring Enabled
Transmitter output optical Power -9 dBm to -2.5 dBm
Receiver Sensitivity Data 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 Power 0 dBm
Supply Voltage 3.3V
Transmitter Differential Line Input Impedance 100Ω
Dimensions 2.3in x 0.54in x 0.33in (L 58.4mm x W13.7mm x   H 8.5mm)
Relative Humidity 5% to 95% Non-condensing

5% to 70% (Recommended)

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

Case Operating Temperature

Commercial 32°F to 158°F (0°C to +70°C)
Extended 14°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 ID Data rate(Gb/s) Media Wavelength Transmission Distance Temperature Range Supply Current


4.25 Multi-mode fiber 850nm 1.24 miles (≤2km) Commercial

32°F to 158°F

(0°C to +70°C)

330 mA


4.25 Multi -mode fiber 850nm 1.24 miles (≤2km) Extended

14°F to 176°F

(-10°C to +80°C)


330 mA


4.25 Multi -mode fiber 850nm 1.24 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:

Parameter Symbol Min Type Max Unit Note
Input Differential Impedance Rin 100 1
Single ended data input swing Vin, pp 180 600 mV
Transmit Disable Voltage VD Vcc–1.3 Vcc V
Transmit Enable Voltage VEN Vee Vee+ 0.8 V 2
Transmit Disable Assert Time 10 us
Differential data output swing Vout,pp 300 850 mV 3
Data output rise time tr 28 ps 4
Data output fall time tf 28 ps 4
LOS Fault VLOS fault Vcc–1.3 VccHOST V 5
LOS Normal VLOS norm Vee Vee+0.8 V 5
Power Supply Rejection PSR 100 mVpp 6


  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:

Parameter Symbol Min Type Max Unit Ref
Output Optical  Power POUT -9 -2.5 dBm
Optical Wavelength λ 840 850 860 nm
Optical Extinction Ratio ER 6 dB
RMS Spectral Width σ 0.85 nm
Transmitter Jitter(peak to peak) FC-PI-4 requirements
RIN RIN -128 dB/Hz
Receiver Sensitivity @ 1.06Gb/s RSENS1 – 20.0 dBm
Receiver Sensitivity @ 2.125Gb/s RSENS2 – 18.0 dBm
Receiver Sensitivity @ 4.25Gb/s RSENS3 – 16.0 dBm 1
Wavelength Range λC 840 860 nm 1
Input Saturation Power (Overload) Psat 0 dBm 1
LOS Assert LOSA -30 dBm
LOS De -Assert LOSD -17 dBm
LOS Hysteresis 0.5 1.0 dB


  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:

Pin Symbol Name/Description Note
1 VEET Transmitter Ground (Common with Receiver Ground) 1
2 TFault Transmitter Fault 2
3 TDis Transmitter Disable. 3
4 SDA 2-wire Serial Interface Data Line 4
5 SCL 2-wire Serial Interface Clock Line 4
6 MOD_ABS Module Absent. Grounded within the module 5
7 RS0 Rate Select.

Open or Low = Module supports 1.25 Gb/s

High = Module supports 4.25 Gb/s



8 LOS Loss of Signal indication. Logic 0 indicates normal operation 7
9 RS1 No connection required 1
10 VEER Receiver Ground (Common with Transmitter Ground) 1
11 VEER Receiver Ground (Common with Transmitter Ground) 1
12 RD- Receiver Inverted DATA out. AC coupled
13 RD+ Receiver Non-inverted DATA out. AC coupled
14 VEER Receiver Ground (Common with transmitter Ground) 1
15 VCCR Receiver power Supply
16 VCCT Transmitter Power supply
17 VEET Transmitter Ground (Common with receiver Ground) 1
18 TD+ Transmitter Non-Inverted DATA in. AC Coupled.
19 TD- Transmitter Inverted DATA in.AC Coupled.
20 VEET Transmitter Ground 1


  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:

Feature Reference Performance
Laser Eye Safety FDA 21CFR 1040.10, 1040.11 IEC/EN 60825-1,2 Class 1 laser product
Component Recognition IEC/EN 60950, UL Compatible with standards
ROHS 2002/95/EC Compatible with standards
Electrostatic discharge(ESD) IEC/EN 61000-4-2 Compatible with standards
EMC EN61000-3 Compatible with standards
Electromagnetic Interference(EMI) FCC Part 15 Class B EN 55022 Class B (CISPR 22A) Compatible with standards