Centellax intros 32G modulator driver for 400G QAM applications

Centellax Inc. has released a 32G modulator driver module for advanced modulation formats such as 400G quadrature amplitude modulation (QAM).

The OA5MMDM is a dual-input, high-performance, broadband 32-Gbps Mach-Zehnder optical modulator driver amplifier with very low jitter and a 5-Vpp output amplitude, as well as excellent output linearity, gain, and group delay flatness, the company asserts. Its gain and power levels are ideally suited for electro-optical test equipment and driving Mach-Zehnder modulators with advanced optical modulation formats like QAM, Centellax adds.

The primary technology being used for 400G long-haul optical transmission is QAM. When the I and Q polarization components of a complex QAM signal are modulated with a four-level pulsed signal, the result is a 16-level QAM signal (or 16-QAM). Because each symbol of the 16-QAM modulated signal has four bits of information, the QAM signal contains 4×32 Gbps of information. The OA5MMDM 32G modulator driver was designed for QAM developers; therefore the I and Q channels of complex modulation schemes are both amplitude and skew matched.

Modulators for QAM schemes require much better linearity than QPSK schemes where the driver is operated in a saturation mode, and noise is attenuated by the amount of saturation that occurs. The OA5MMDM driver amplifier noise is transparent on the output because the gain is linear. The bandwidth of the OA5MMDM is also excellent because any bandwidth restrictions and rounding of the eye cause the multiple eye openings to be closed, Centellax asserts.

“We designed the OA5MMDM to address the need for a ‘connectorized’ dual-channel 32G modulator driver for the 400G long-haul transponder module developers,” said Jeff Meyer, Centellax chief technical officer. “It’s important for us to get in at the forefront of this technology and the OA5MMDM is just the beginning of our development efforts.”