Fujitsu Demonstrates Optical Components For 100G Metro Network At OFC 2014

Posted on Mar 11 2014 - 11:27am by Editor2

Fujitsu Optical Components Limited (FOC) announced today that a live demonstration of the optical components used to make a 100G CFP coherent transceiver will take place at OFC (*1) 2014 next week in San Francisco, California, USA. The demonstration can be viewed in FOC’s booth #3445 at the Moscone Center, March 11-13, 2014.


New services such as mobile broadband using smart devices, social networking, cloud computing, and on-line streaming have led to a rapid increase in the volume of communications traffic. This has created a great demand for 100G optical networks. The requirement for Core Networks to handle larger capacity and longer distance on their links has led to a spread of 100G optical networks using digital coherent transmission systems (*2). The requirements on IP networks between data centers and metro networks to achieve larger capacity, higher port density, and lower cost has similarly led to the spread of 100 GbE optical networks.For core network applications the100G Coherent Transceiver defined in the OIF (*3) 100GLH-EM specification for long distance and high capacity transmission systems has been deployed. For metro network though a smaller size, lower power consumption and lower cost coherent transceiver is required.
For this application a 100G CFP Coherent Transceiver with the same interface as the CFP Transceiver which is popular in LAN will be used. To develop a CFP Coherent Transceiver smaller size, lower power consumption, and lower cost optical devices are also necessary.

In this demonstration, we will show a solution to achieve a 100G CFP Coherent Transceiver. The optical transmitting and the optical receiving sections are separated in our demo. In the optical transmitting section a 100G DP-QPSK (*4) optical signal is generated with our in-house compact InP Modulator. This optical signal is then demodulated using the in-house compact Integrated Coherent Receiver in the optical receiving section. The signal’s waveform distortion from the transmission path will then be compensated by the coherent DSP and a resultant bit error rate which meets all requirements displayed. This demo will show the realization of a 100G CFP Coherent Transceiver using compact optical devices.

100G DP-QPSK InP Modulator

This is a Mach-Zehnder modulator made from Indium Phosphide (InP) designed to meet the OIF specifications for 128 Gbs (32 Gbaud) DP-QPSK applications. The modulator incorporates a DP-QPSK optical modulation circuit, polarization beam combiner, and a monitor photodiode all inside of a compact package. The FOC design allows for compact size, wide bandwidth, and low drive voltage operation.
(Note) The InP DP-QPSK optical modulation circuit used in this product is co-developed with NTT Electronics Corporation.

100G DP-QPSK Integrated Coherent Receiver

This is a 100G integrated receiver compliant with the OIF specifications for 100Gbps digital coherent receiving systems. The integration of 90° Hybrids (*5), Balanced Receivers (*6), Polarizing Beam Splitters, VOA function (*7) and monitor function (*8) all into a single package by PLC (*9) and micro-assembly technologies allows FOC to realize a compact, low-cost and high-performance 100G integrated receiver for use in a CFP Coherent Transceiver.

Acronym for Optical Fiber Communication Conference and Exhibtion

(*2) Converts the received optical signal to an electrical signal in the optical receiving section after combining the received optical signal with a local reference light. The waveform distortion that occurs in the optical transmission path is then compensated for through digital signal processing. This technique allows for significant reduction in system cost through the elimination of optical dispersion compensators and optical amplifiers (for loss compensation).

(*3) Acronym for Optical Internetworking Forum. The OIF is an organization that promotes standardization for the equipment and components used in optical networks

(*4) Acronym for Dual-Polarization Quadrature Phase Shift Keying. It is a method of phase modulation for digital signals in which 2 bits of data are allocated to each of 4 modulated optical phases (0, 90, 180, 270°) for both P-polarized and S-polarized light.

(*5) Optical mixer component that is used for coherent signal demodulation purposes in heterodyne and intradyne detection systems. The hybrid mixes the incoming optical data signal with light from an input optical reference source and guides the combined signal to the balanced receivers.

(*6) A receiver consisting of two photodiodes which receives differential optical output from delay line interferometers and 90 degree Hybrids. Improved receiver characteristics are achieved by using the difference between the two photodiode currents.

(*7) Acronym for Variable Optical Attenuation function. Function to variably attenuate the optical signal strength. Adjusting the attenuation amount in accordance with the received optical signal strength allows for acceptance of a wide dynamic range of optical input power.

*8) Function to detect the received optical signal strength. To detect only the received optical signal suppression of the high power local reference light used in heterodyne and intradyne detection systems is required.

(*9) Acronym for Planar Lightwave Circuit. Optical circuit chip on a silicon or quartz substrate containing optical waveguides with accuracies on the order of an optical wavelength