100G single labmbda transceiver applies PAM4 modulation to transmit 100G data over a single wavelength. The optics are winning more popularities as they enable operators to migrate to 400G in an easy way. So FS introduces three types of 100G single labmbda transceivers, 100GBASE-DR QSFP28, 100GBASE-FR QSFP28, 100GBASE-LR QSFP28.
FS generic 100G-DR / FR / LR transceiver modules include a gearbox chip to convert the 4 x 25G NRZ electrical signals to a 1 x 100G PAM-4 optical signal. The transmission distance can reach up to 10km over duplex LC single mode fiber cables. They are designed with COB (chip on borad) packaging. Functions like host FEC and EMC(Electro Magnetic Compatibility) can be supported. The following table shows more specific features of these FS QSFP28 transceivers.
|Max Cable Distance||500m||2km||10km|
|Commercial Temperature Range||0 to 70°C (32 to 158°F)||0 to 70°C (32 to 158°F)||0 to 70°C (32 to 158°F)|
|CDR (Clock and Data Recovery)||TX & RX Built-in CDR||TX & RX Built-in CDR||TX & RX Built-in CDR|
|Transmit and Dispersion Penalty||3.4dB||3.4dB||3.4dB|
|Protocols||IEEE 802.3cd 100GBASE-DR Specification compliant||100G Lambda MSA 100G-FR Specification compliant||100G Lambda MSA 100G-LR Specification compliant|
QSFP28-DR-100G single lambda optical transceiver supports up to 500m, which is suitable for the data center leaf-spine connectivity where the fiber length seldom exceeds 100m. It also enables the migration from 100G to 400G.
Figure1: QSFP28-DR-100G solution
QSFP28-FR-100G has the same reach of 2km over duplex SMF and uses duplex LC connectors with 100G CWDM4 transceiver. It's very popular in data centers. Because it has the same reach, fiber, and connector as 100G CWDM4, it can be used in the applications that 100G CWDM4 module is used, such as high-performance computing networks, enterprise core and distribution layer applications. By the way, QSFP28-FR-100G also allows you to upgrade to 400G with 400GBASE-XDR4 QSFP-DD module and MTP-LC breakout cable.
Figure2: QSFP28-FR-100G solution
QSFP28-LR-100G, with the max reach of 10km distance, can be used to connect different buildings that may not even be in the same city. So it's a good choice for campus networks building.
The main differences among FS 100G-DR / FR / LR transceiver modules are tx power, receiver sensitivity, powerbudget, transmission distance which is the biggest difference. Different distances may be used in different environments. From the above comparison, I hope it would be helpful for you to make a wise decision when choosing these FS QSFP28 optics.