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Optical circuit for super-high-speed measurement of a phase modulation waveform (optical sampling oscilloscope)

- This circuit measures signals from an optical super-high-speed transmission system with a high sensitivity and assesses the quality of the signals. -

Do you have the problems shown below? This technology will solve them!

As communication networks become increasingly varied and more advanced with the advent of multimedia, VOD (Video On Demand), ubiquitous, Web2.0 and cloud computing services, demands for high-speed and high-capacity transmission systems are growing. Such demands will continue to intensify as fully fledged P2P (peer to peer communication) and the IoT (Internet of things) become widespread.

This in turn gives rise to demands for technology for measuring super-high-speed optical signals. The technology described here is the answer to the following needs:

  • I want to monitor the waveform of a high-speed optical signal at 40 Gbit/s or above with a high degree of accuracy and sensitivity.
  • I want a waveform monitoring capability that can detect not only changes in optical intensity but also changes in phase.

Overview

The speed of transmission systems is ever increasing. Today, systems that operate in excess of 100 Gbit/s are being studied. As the signal speed increases, it becomes difficult for an electrical oscilloscope to keep pace with the signal speed in measuring optical signal intensity. If phase modulation based on digital coherent optical transmission is to be adopted to increase the transmission speed, it is necessary to monitor the phase waveform.

This technology solves these problems by using a linear optical sampling method. It makes it possible to monitor both signal intensity and phase over a measurement range of several hundred GHz (Fig.1).

The linear optical sampling method has the following features (Fig.2):

  • (1) It can measure high-speed signals in the terahertz range.
  • (2) It can observe the waveform of both intensity modulation and phase modulation (or frequency modulation).
  • (3) It has a high sensitivity because it uses only a light receiving element.

In the coming years the information society will require ever faster and higher capacity communication networks. This technology makes it possible to measure future high-speed, high-capacity networks, and to assess their quality. Therefore, it will assist corporations in venturing into new businesses or providing a wide variety of services.

[Fig.1] Application area of the super-high-speed optical signal measurement technology
Fig.1 Application area of the super-high-speed optical signal measurement technology

[Fig.2] Technical overview of the linear optical sampling method
Fig.2 Technical overview of the linear optical sampling method

Application fields

  • Information communication, measurement and assessment
  • Cables, civil engineering, maintenance, inspection, operations and maintenance.

Advantages

This technology makes it possible to monitor both signal intensity and phase over a measurement range of several hundred GHz at high speed and with a high sensitivity. This requirement is essential for measuring future super-high-speed communication networks and assessing their quality.

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