Low return loss etching diffraction grating wave-length division multiplexer

Abstract

A wave length division multiplexer with etched diffraction raster and low return loss is composed of input waveguide, output waveguide, etched raster, and free propagation region. The incident point and outgoing point of input and output waveguides are positioned on a circle. The center of said etched raster is positioned at a tangential point between said circle and another circle. The direction of each reflecting tooth surface for said raster is determined by incident and outgoing directions to reflect the incident light to same position where there is no output astigmation, resulting in minimal optical return loss.

Description

technical field [0001] The invention relates to the field of optical communication wavelength division multiplexing, in particular to a low return loss etching diffraction grating wavelength division multiplexer. Background technique [0002] Wavelength Division Multiplexing (WDM) technology can multiplex tens or even hundreds of wavelengths in a single fiber to meet the increasing demand for bandwidth, and is one of the effective methods to improve communication capabilities. Wavelength division multiplexing technology has been improved so that it can transmit hundreds of wavelengths of laser light, and the interval between each wavelength is 1.6, 0.8 or 0.4nm, or even 0.2nm. This technology is called Dense Wavelength Division Multiplexing (DWDM). WDM has been widely used in long-distance transmission, and has also begun to enter short-distance optical communication networks. [0003] The wavelength division multiplexer is the most critical device in the wavelength divisio...

AI Technical Summary

Problems solved by technology

However, due to environmental influences such as temperature, the wavelength of the incident light will drift. If the wavelength drift reaches the wavelength that the input waveguide can receive, return loss will occur.

In addition, the background noise of the EDFA used for optical signal amplification in the optical communication system has a wide frequency spectrum, and the noise light returns to the incident waveguide, which will cause return loss

[0005] The general way to reduce the return loss is to use the interface with an inclined angle, but this method can only reduce the return loss caused by the interface, and it is invalid for the return loss caused by other factors such as grating reflection

The use of optical isolators in the optical path can reduce the return loss as a whole, but the use of optical isolators increases the cost and complexity, and adds additional insertion loss

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