Optical network unit, wave length branch device and wave length multiplex access system

Abstract

An optical wavelength-division multiplexing access system is provided which reduces the requirement for temperature control circuits for the generation of optical signals, and which connects a large number of ONUs while allowing for standardization of the ONUs (i.e. reduction of the number of types of component incorporated therein). In an optical wavelength division multiplexed access system, a center unit (OSU) and n optical network units (ONUs) are connected together via a wavelength splitter and optical fiber transmission lines, and downstream optical signals from the OSU to the ONUs and upstream optical signals from the ONUS to the OSU are transmitted in both directions, the wavelength spacing ”»d (optical frequency spacing ”fd) of the downstream optical signals is set to twice or more the wavelength spacing ”»u (optical frequency spacing ”fu) of the upstream optical signals, each ONU transmits an upstream optical signal whose optical spectral width is twice or more ”»u (”fu), and the wavelength splitter spectrum slices the upstream signals transmitted from the ONUs into wavelengths (optical frequencies) whose optical spectral widths are mutually different within ”»u (”fu), and wavelength-division multiplexes them and transmits to the OSU.

Description

technical field [0001] The invention relates to an optical wavelength multiplexing access system for bidirectionally transmitting optical signals between a central unit (OSU) and a plurality of optical network units (ONU). [0002] This specification claims the benefit of Japanese Patent Application No. 2002-378079 filed on December 26, 2002, the content of which is made a part of this specification. Background technique [0003] As one form of the optical multiplexing access system, an optical wavelength multiplexing access system in which each ONU occupies a different wavelength on a star optical access line in which a plurality of signals are multiplexed and separated via a wavelength splitter is being studied. [0004] Figure 14 A configuration example of a conventional optical wavelength multiplexing access system is shown (Japanese Unexamined Patent Publication No. 2000-196536. Hereinafter referred to as Patent Document 1). Among them, it is exemplified that one wave...

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Problems solved by technology

[0018] On the other hand, as mentioned above, on a star optical access line that combines and distributes multiple signals through an optical power splitter, when each ONU occupies a different wavelength and performs bidirectional communication with the OSU, each ONU must be equipped with a Light source, so the problem of cost increase due to the multi-variety of ONU

In addition, there is no ONU configuration that clearly adopts the spectrum division method to perform bidirectional communication between the OSU and each ONU on the star optical access line that combines and distributes multiple signals via an optical power splitter.

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