Optical transmitter with hybrid modulation format

Abstract

The invention provides an optical transmitter with a hybrid modulation format. The optical transmitter is applied to a passive optical access network and a long-distance optical transmission system, wherein the passive optical access network is formed by integrating a wavelength division multiplexer and an optical branching device. The optical transmitter comprises an I / Q modulator 1, an I / Q modulator 2, a delay line interferometer and a Mach-Zehnder modulator. The I / Q modulator 1 is in cascade connection with the delay line interferometer, then is in cascade connection with the I / Q modulator 2 and lastly, is in cascade connection with the Mach-Zehnder modulator. The two I / Q modulators are respectively provided with two data input ports, and the Mach-Zehnder modulator is provided with one data input port. The optical transmitter is controlled to output an optical signal with the self-adaptation hybrid modulation format by controlling the on-off and the signal amplitude of the data input ports and the bit and the phase position delay of the delay line interferometer. By means of the optical transmitter, QPSK modulation, 8 QAM modulation and circular 16 QAM modulation can be achieved, and hybrid transmission formed by various modulation formats in any proportional mode can also be achieved. The optical transmitter can be applied to complex transmission links under the wavelength division multiplexing passive optical network environment, and the frequency spectrum utilization efficiency can be effectively improved.

Description

technical field [0001] The invention relates to an optical transmitter, in particular to an optical transmitter with a mixed modulation format. Background technique [0002] There are no active devices in the optical distribution network of the Passive Optical Network (PON), and each optical branch node uses a passive optical splitter. Compared with wireless and copper optical access networks, it has the advantages of large bandwidth, low loss, and strong coverage. Therefore, PON has received extensive attention from the industry, and PON products represented by GPON and EPON have been widely used. With the vigorous development of Internet data services, higher requirements are put forward for the downlink bandwidth of the optical access network. At present, the scientific research community is focusing on the new generation of wavelength division multiplexing PON technology to provide data transmission rates up to 10Gbps. However, this technology is not flexible enough in...

AI Technical Summary

Problems solved by technology

[0006] In order to solve the problem of balance between arbitrary continuum efficiency and transmission distance and loss in the existing wavelength division multiplexing passive optical network, the present invention provides a passive optical An adaptive mixed modulation format optical transmitter in the network, and the transmitter can also be applied to a long-distance optical transmission system

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