World wide Optical Networking Knowledge Center

The goals of the Open ROADM Multi-Source Agreement are  (1) the disaggregation and opening up of traditionally proprietary ROADM systems   (2) the SDN-enablement of traditionally fixed ROADMs   There are many ways to disaggregate ROADM systems, e.g. hardware disaggregation (e.g. defining a common shelf) or functional disaggregation (less about hardware, more about function). Due to the complexity of common shelves, the Open ROADM MSA chose the functional disaggregation first. We defined three optical functions: pluggable optics, transponder and ROADM (the optical switch part with amplifiers, couplers, WSS, etc.). Common shelves can be introduced at a later point for some functions, like transponders, if they make sense as an extension of the models.   All of the three disaggregated functions (pluggable optics, transponder and ROADM) are controllable through an open standards-based API (written in the data modeling language YANG) that can be accessed through a...

Mach–Zehnder Modulator  Optical modulators are used for electrically controlling the output amplitude or the phase of the light wave passing through the device. To reduce the device size and the driving voltage, waveguide-based modulators are used for communication applications. To control the optical properties with an external electric signal, the electro-optic effect, or Pockels effect, is used, where the birefringence of the crystal changes proportionally to the applied electric field. A refractive index change results in a change of the phase of the wave passing through the crystal. If you combine two waves with different phase change, you can interferometrically get an amplitude modulation.    The device in Figure 1 is a Mach–Zehnder modulator. The input wave is launched into a directional coupler. The power of the input is split equally into the two output waveguides of the first directional coupler. Those two waveguides form the two arms of a Mach– Zehnder interf...

 Optics performance monitoring Carrier Frequency Offset (MHz)—Carrier frequency offset in megahertz (mHz), which denotes the difference between the carriers (frequency shift in the receive spectrum) between the expected Rx carrier frequency and the actual carrier frequency CFO—Threshold values for carrier frequency offset CFO-Min—Low threshold setting trigger when the carrier frequency offset falls below this minimum value CFO-Avg—Average threshold setting trigger when the carrier frequency offset crosses this average value CFO-Max—High threshold setting trigger when the carrier frequency offset rises above this maximum value Chromatic Dispersion—Lane or residual chromatic dispersion measured at the Rx transceiver port, which denotes the spreading of the signal in time resulting from the different speeds of light rays CD—Threshold values for chromatic dispersion CD-Min—Minimum value of the residual chromatic dispersion measured at the Rx transceiver port CD-Avg—Average value of t...

  Introduction: The CFP2-DCO form factor of an optical transceiver which can support 100Gbit/s, 200Gbit/s, 300Gbit/s and/or 400Gbit/s line interface rates for Ethernet, ITU-T OTN, OIF and other applications. This specification is an extension to the CFP2 MSA MIS v2.6 (r06a) [2] and the CFP2 MSA Hardware Specification Rev. 1.0 [3] to support coherent applications in CFP2 form factor with a digital host interface.   Functional Description:  A functional block diagram of the CFP2-DCO is illustrated in Figure 1. Key module functions include transmitter optics, receiver optics, optical MUX/De- MUX in case of multi-carrier link, interface ICs, module controller supporting a MDIO/MDC management interface, and power conversion for a single +3.3V DC power supply from the host. The CFP2-DCO is a hot pluggable module form factor designed for optical networking applications.     The module electrical interface has been generically specified to allow for suppli...