Optical communication systems, optical transmitters and optical receivers

A technology of optical communication system and optical receiver, which is applied in the field of optical communication system and can solve problems such as inability to receive optical signals

Inactive Publication Date: 2017-12-26
FUJITSU OPTICAL COMPONENTS LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In variable mesh or meshless communication, optical signals cannot be received even with digital signal processing using PADE

Method used

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  • Optical communication systems, optical transmitters and optical receivers
  • Optical communication systems, optical transmitters and optical receivers
  • Optical communication systems, optical transmitters and optical receivers

Examples

Experimental program
Comparison scheme
Effect test

no. 1 approach

[0055] Figure 2A A single polarization (SP) QPSK optical transmitter 10A is shown in a schematic block diagram, Figure 2B A dual polarization (DP) QPSK optical transmitter 10B is shown in a schematic block diagram. image 3 A SP-QPSK optical receiver 20A is shown in a schematic block diagram, Figure 4 A DP-QPSK optical receiver is shown schematically.

[0056] Regardless of whether polarization division multiplexing is used or not, the structures and methods of the embodiments are applicable. Embodiments are also applicable to any modulation scheme (eg, multi-level amplitude modulation), not limited to QPSK. The method and structure of the embodiment are also applicable to the case of polarization division multiplexing ( Figure 2B and Figure 4 ) and the case without polarization division multiplexing ( Figure 2A and image 3 ). Therefore, the optical transmitters 10A and 10B are collectively referred to as "optical transmitter 10", and the optical receivers 20A a...

no. 2 approach

[0099] Figure 12 is a schematic block diagram of the optical receiver 40 according to the second embodiment. The configuration on the sending side is the same as that described in the first embodiment, for example, using Figure 2A The optical transmitter 10A. although Figure 12 The SP-QPSK optical receiver is shown, but the main operation is also applicable to the DP-QPSK optical receiver, and its description is omitted.

[0100] The modified part includes a receiving front end, which is connected to a coupler 53 that splits the optical signal, an optical-to-electrical (OE) converter 54 that converts the optical signal into an electrical signal, a power monitor 55 that monitors the optical power, and a controller (second controller )56, these components are added.

[0101]The received optical signal is split by a coupler 53 . One component is input to the 90-degree hybrid optical mixer 41 , and the other component is input to the OE converter 54 . The power monitor 55...

no. 3 approach

[0113] Figure 19 is a schematic block diagram of the optical transmitter 70 used in the optical communication system according to the third embodiment. In the third embodiment, a training pattern for frequency offset is inserted on the transmission side.

[0114] The optical transmitter 70 has a symbol mapper 71 , a training pattern generator 73 and a data combiner 72 . The training pattern generated by the training pattern generator 73 is combined with the output of the symbol mapper 71 at a data combiner 72 . The serializer 75, driver 76, and modulator 77 provided after the data combiner 72 have the same structure as those shown in the first embodiment and perform the same operations.

[0115] The training pattern generator 73 generates a pattern that enables the modulator 77 to output a continuous wave for a predetermined period of time and enables the receiver to detect a beat waveform. For QPSK, the same data with the same symbol is successively output.

[0116] Fi...

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PUM

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Abstract

Optical communication systems, optical transmitters and optical receivers. An optical communication system includes an optical transmitter and an optical receiver connected to the optical transmitter via a transmission line, in the optical communication system, the optical transmitter transmits a continuous wave optical signal, and the continuous wave optical signal communicates with the optical The local oscillator signals in the receiver are combined to enable beat detection, and the optical receiver acquires beat waveforms by digital sampling by detecting the optical signal with the local oscillator signals, prior to demodulation with the Frequency analysis is performed on the digitally sampled data of the beat waveform, and the local oscillator frequency is controlled based on the beat frequency.

Description

technical field [0001] Embodiments discussed herein relate to optical communication systems, optical transmitters and optical receivers used in the optical communication systems. Background technique [0002] In coherent optical communication using homodyne detection, the transmission signal frequency on the transmission side and the local oscillation frequency on the reception side must coincide with each other. It is technically difficult to make the optical frequencies completely coincide with each other. In an optical receiver, based on a feedback signal from a digital signal processor, clock pulses are generated in synchronization with data to sample data at a clock frequency. For example, see Japanese Patent Application Laid-Open No. 2009-60309. However, if the signal is phase modulated, the phase of the light wave may change according to the signal components. In this case, it is possible that even if the received signal is mixed with the signal from the local osci...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04B10/548H04B10/66H04B10/2513H04J14/02
CPCH04B10/63H04B10/6164
Inventor 坂井良男赤司保
Owner FUJITSU OPTICAL COMPONENTS LTD
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