Traditionally， the maximum transmission rate of the electricity-based SFP is 1G， lacking the technology and product to convey the 2.5 G&beyond high-speed links．At present， optical transmission is the primary way to support 2.5 G&beyond high-speed SFP Transceiver Module links．
Based on common cable materials， this paper employs electromagnetic field and circuits joint-simulations to design low-cost， high-quality SFP cable jumper in order to replace the 3G&below SFP fiber jumpers which is composed of high-speed optical module and fiber．
1. SFP Transceiver Module Application Requirements
Small Form-Factor Pluggable SFP (Small Form Pluggables) module is pin
High-speed optical interconnect interface and design, 1000base-sx sfp transceiver module interface commonly used rate has 155Mbps, 1.25Gbps and 2.5Gbps, the highest rate of up to 10Gbps, more mining With LC connector. The widely used SFP optical modules exist several disadvantages:
1)sfp transceiver module contains expensive lasers and photodetectors, use, and maintenance costs Higher;
2)light jumper connection and laying certain technical requirements, ease of use is not Strong;
3)SFP transceiver module is active devices, not only there is a big power, and capacity
Easy to aging and failure.
Electrical link optical link compared to the cost and stability, ease of use has a more Big advantage, but there is more than ripe for the 1G SFP electrical interface Ethernet link Road, no more than 2.5G technology and products for high-speed links. This design Based on the general design of the cable material cost, high-quality SFP cable jumpers in Upon completion of up to 3Gbps data transfer within 10 meters range, short-range connections Now replace the optical module and cable.
2. SFP Transceiver Module design
SFP design is a high-speed signal integrity problems, and gigabit sfp ports is passUse of connectors, the input and output interface should comply with the national standard.This design from the basic.The transmission line.For planar transmission line, first of all it is dispersive, affect the letter.Transmission;Second on the transfer if there is discontinuous, will not introduce circuit.Reflection, impact continuity, input, output and transmission performance;The third is the transport.There is a radiation and mutual coupling between lines.This design USES the electromagnetic field and circuit of the imitation.True technology, choose appropriate transmission line, optimization design, structure and size effectively.To overcome the effects of the above three points.
In order to reduce the cost of production, PCB board selects the dielectric constant is about 4.3 FR4 multilayer board, a total thickness of 1 mm.According to the design requirements, SFP is poor Impedance: 100 + 10 Ω;Ω single-ended impedance: 50 plus or minus 2.PCB board is divided into three zones.Domain to carry on the design.
Code rate 5 GBPS signal output eye diagram