What is 400G?

A 400G optical module is a type of high-speed optical transceiver module that enables the transmission of data at a rate of 400 Gigabits per second (Gbps) over optical fibers. These modules are typically used in data center interconnects, long-haul and metro networks, and other high-speed networking applications that require high bandwidth and low latency.

The 400G optical module uses advanced optical technologies such as wavelength division multiplexing (WDM), coherent detection, and digital signal processing (DSP) to achieve high-speed data transmission over long distances with low error rates. These modules come in various form factors, including QSFP-DD, OSFP, and CFP8, and support different optical interfaces such as single-mode and multimode fibers.

In summary, the 400G optical module is a critical component of modern high-speed networking infrastructure that enables faster, more efficient, and more reliable data transmission over long distances.

What is Coherent Optics?

Coherent optics is a type of optical communication technology that uses advanced modulation techniques to increase the capacity and reach of optical networks. Unlike traditional direct detection optical communication, which relies on simple on-off keying (OOK) modulation, coherent optics uses more sophisticated modulation schemes such as quadrature amplitude modulation (QAM) to encode multiple bits per symbol.

In coherent optics, the transmitter and receiver use lasers to generate and detect optical signals, respectively. The transmitter uses a digital signal processor (DSP) to modulate the laser light, while the receiver uses a coherent detection technique to recover the original signal. Coherent detection uses a local oscillator laser to create a phase reference that enables the receiver to measure the phase of the received signal. By measuring both the amplitude and phase of the signal, coherent optics can achieve higher spectral efficiency and longer transmission distances than traditional direct detection optical communication.

Coherent optics is widely used in long-haul and metro networks, as well as in data center interconnects, where high bandwidth and low latency are critical. Coherent optics is also a key enabler of emerging technologies such as 5G wireless networks, cloud computing, and artificial intelligence, which require high-speed and low-latency communication between data centers and other network nodes.