At Fibrenet we often get asked why the price jumps up suddenly as the distance/reach increases such as between 60, 70 and 80km 10G BIDI SFPs. The reason is that they have to use EML lasers for the longer reach to provide a quality transmission. The below gives an insight which may (we hope) prove interesting.
DFB (Distributed Feedback) and EML (Electro-Absorption Modulated Laser) are two types of lasers that are commonly used in SFP (Small Form-factor Pluggable) transceivers. These lasers are used to transmit and receive data in optical communication systems.
DFB Lasers: DFB lasers are widely used in SFP transceivers due to their high stability and efficiency. These lasers use a periodic grating structure to produce a narrow optical spectrum that is precisely aligned with the transmission channel. This alignment allows for very low bit error rates and high data transfer rates.
The structure of a DFB laser involves a layer of material with a periodic grating pattern on its surface. Light emitted by the laser passes through this grating and experiences constructive and destructive interference, resulting in a narrow and well-defined optical spectrum.
EML Lasers: EML lasers, on the other hand, are a newer technology that are gradually replacing DFB lasers in some applications. These lasers use an electrical signal to modulate the absorption of light within the laser cavity, resulting in an output signal that is directly proportional to the electrical input.
EML lasers are often considered to be more flexible than DFB lasers, as they allow for more dynamic control of the laser output. This makes them particularly useful for applications that require rapid changes in the transmitted signal, such as in high-speed optical networks.
In addition to their greater flexibility, EML lasers are also more power-efficient than DFB lasers. This is because they do not require the additional energy required to generate the grating structure used in DFB lasers.
Conclusion: In conclusion, both DFB and EML lasers have their own unique advantages and disadvantages. DFB lasers are highly stable and efficient, making them ideal for applications that require a consistent and reliable output signal. EML lasers, on the other hand, offer greater flexibility and power efficiency, making them suitable for applications that require rapid changes in the transmitted signal.
In the end, the choice between DFB and EML lasers in SFP transceivers will depend on the specific requirements of the application and the desired level of performance. Both technologies are widely used in the optical communication industry and continue to evolve and improve over time.
Fibrenet supplies 1G, 10G, 25G, 40G and 100G BIDI options. If you would like to speak to one of our team, please call today on 01666 715 715 or contact us here and our knowledgeable sales team will be able to assist you. As always, please get in touch if we can help explain anything or products you may require are not listed online.