Industry Insights

Keysight Helps NeoPhotonics Accelerate 400G/600G Development by a Year

2019-02-28  |  4 min read 

In the past, coherent optical technology was primarily used for the superfast data highways in telecom networks. High-quality fiber is expensive. However, considering the cost-per-bit of transport for long-distance transmission, coherent optical technology is efficient and affordable in telecom networks. Until now, it was too expensive for use in short distances such as DCI, which are typically less than 120 Km apart.

Introducing 400ZR

The Optical Internetworking Forum (OIF) is developing the 400ZR standard for transmitting a 400 gigabit Ethernet (400GE) payload over DCI links up to 120 km using dense wavelength division multiplexing (DWDM) and higher order modulation, such as quadrature amplitude modulation (QAM). Higher-order QAM signaling enables significantly faster data transmission rates and higher levels of spectral efficiency.

The 400ZR standard will reduce the cost and complexity for the use of coherent optical technology in high bandwidth data center interconnects. The specification recommends 16-QAM at a symbol rate of about 60 GBaud. Achieving this rate within a maximum power consumption of 15 W and considering the space constraints in the target form factors, optical transceivers require dense electronic and photonic integration with tighter specifications and performance margins for all components. These small form factors need small component sizes and low electrical power consumption. These restrictions create challenges for digital signal processor (DSP) and component suppliers. Although not defined by the 400ZR specification, optical transceivers should be in a small format such as octal small format pluggable (OSFP) or double density quad small form factor pluggable (DD-QSFP).

NeoPhotonics Accelerates 400G/600G Optical Component Development by a Year

NeoPhotonics Corporation (NeoPhotonics) designs and manufactures optoelectronic solutions for high-speed communication networks in telecom and data center applications. It develops high-speed optical components for 400G, 600G, and beyond network communications including DCI.

Generally, high-speed silicon that drives optical transceivers lags optics by about a year. While developing its latest coherent optical subassembly (COSA) designed for integration into an octal small form factor pluggable (OSFP) module, NeoPhotonics’ engineers worked with Keysight’s state-of-the-art test equipment to demonstrate the expected performance of their final module designs. NeoPhotonics aims to optimize its products in two directions: for very high speeds and small size. NeoPhotonics’ new COSA product combines its coherent receiver and modulator technologies in a single co-packaged part suitable for use in an OSFP form factor, and eventually also within a DD-QSFP form factor.

With the DSP silicon for 400ZR transceivers still a year out, NeoPhotonics had no way of assessing its optical components, so they turned to Keysight for help. Read the case study ‘Coherent Optical Component Test Enables 1.2 Terabit Applications’ to learn more about QAM signaling basics, 400ZR, and Keysight’s solutions that accelerated NeoPhotonics’ development of 400G and 600G optical components and sub-assemblies by a year.