imec's novel ADC promises faster sampling rates

The analogue-to-digital and digital-to-analogue converters (ADCs/DACs) are like the equals sign in mathematics.

Joris Van Driessche

The equals sign is taught as showing two sides of an equation being the same. But really, it is a gateway between two worlds. The same applies to the ADC and DAC, which equate between the analogue and digital worlds.

Progress in wireline communications, whether client-side optics or coherent optical modems at 800 gigabits and soon 1.6 terabit, means converters must sample at higher rates.

In February, at the IEEE International Solid-State Circuits Conference (ISSCC) in San Francisco, imec detailed a proof-of-concept chip design that promises to advance high-speed ADCs.

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Huawei sets transmission record with new modulator

Coherent discourse: Part 1

A paper from Huawei and Sun Yat-Sen University in the January issue of the Optica journal describes a thin-film lithium niobate modulator. The modulator enabled a world-record coherent optical transmission, sending nearly 2 terabits of data over a single wavelength.

Maxim Kuschnerov

Much of the industry’s focus in recent years has been to fit coherent optical technology within a pluggable module.

Such pluggables allow 400-gigabit coherent interfaces to be added to IP routers and switches, serving the needs of the data centre operators and telecom operators.

But research labs of the leading optical transport vendors continue to advance high-end coherent systems beyond 800-gigabit-per-wavelength transmissions.

Optical transport systems from Ciena, Infinera and Huawei can send 800-gigabit wavelengths using a symbol rate of 96-100 gigabaud (GBd).

Acacia Communications, part of Cisco, detailed late last year the first 1.2-terabit single-wavelength coherent pluggable transceiver that will operate at 140GBd, twice the symbol rate of 400-gigabit modules such as 400ZR. 

Now Huawei has demonstrated in the lab a thin-film lithium niobate modulator that supports a symbol rate of 220GBd and beyond.

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