There are two main types of 200G transceiver modules defined by the agreement: 8*25G NRZ QSFP-DD (double density) and 4*50G PAM4 QSFP56. But we're going to discuss 200G NRZ QSFP-DD.
As a key accessory in the communications industry, optical transceiver was required to meet low power consumption, low latency, easy deployment, and low cost. At present, the power consumption of 200G NRZ announced by major manufacturers is about 2-3W, which is helpful for saving power and cooling costs in the computer room. In addition, NRZ transceiver has relatively stable performance which can avoid delay in terms of data exchange.
200G SR8, 200G PSM8, and 200G LR8 are common used in large data centers. 200G QSFP-DD SR8 uses an 8-channel 850nm vcsel array; 200G QSFP-DD PSM8 is single-mode parallel, wavelength division multiplexing technology, and the transmission distance can reach 10km; 200G QSFP-DD LR8 uses LAN-WDM technology to achieve longer-distance transmission.
