1.25G SFP 1310nm 20km is very popular products, it's widely exported to USA, Russia, Germany, Europe, Korea, India etc.
With good quality, price.

 1.25Gbps SFP Optical Transceiver, 20km Reach

Features

•  Dual data-rate of 1.25Gbps/1.063Gbps operation
•  1310nm FP laser and PIN photodetector for 20km transmission
•  Compliant with SFP MSA and SFF-8472 with duplex LC receptacle
•  Digital Diagnostic Monitoring:
•  Internal Calibration or External Calibration
•  Compatible with SONET OC-24-LR-1
•  Compatible with RoHS
•  +3.3V single power supply
•  Operating case temperature:
•  Standard :  0 to +70°C
•  Extended : -20 to +85°C
•  Industrial : -40 to +85°C 

Applications

•  Gigabit Ethernet
•  Fiber Channel
•  Switch to Switch interface
•  Switched backplane applications
•  Router/Server interface
•  Other optical transmission systems

Description

The SFP transceivers are high performance, cost effective modules supporting dual data-rate of 1.25Gbps/1.0625Gbps and 20km transmission distance with SMF.

The transceiver consists of three sections: a FP laser transmitter, a PIN photodiode integrated with a trans-impedance preamplifier (TIA) and MCU control unit. All modules satisfy class I laser safety requirements.

The transceivers are compatible with SFP Multi-Source Agreement (MSA) and SFF-8472. For further information, please refer to SFP MSA.