Upgrading method, system and apparatus of low-density wavelength division multiplexing system

An upgradeable low-density wavelength division multiplexing (WDM) system, comprising:

• a transmitter side, comprising an adjustable interleaved multiplexer or a coupler, one or more wavelength conversion units, one or more fixed wavelength multiplexing units, wherein an optical signal output by the wavelength conversion unit is multiplexed through the fixed wavelength multiplexing unit, the optical signal output by the fixed wavelength multiplexing unit is further multiplexed by the adjustable interleaved multiplexer or the coupler;
• a receiver side, comprising an adjustable interleaved demultiplexer, one or more fixed wavelength demultiplexing units, one or more wavelength conversion units, wherein the adjustable interleaved demultiplexer interleaves and demultiplexes the received optical signal, transfers the interleaved and demultiplexed optical signal to the fixed wavelength demultiplexing unit to complete the demultiplexing of a wavelength signal, and transfers the demultiplexed wavelength signal to the wavelength conversion unit;
• and
• a control unit, configured to transmit an adjust command to the adjustable interleaved demultiplexer when a wavelength usage of the low-density WDM system reaches a threshold;
• wherein the adjustable interleaved demultiplexer is configured to perform adjustment according to the received adjust command until requirements for a demultiplexing parameter of a high-density WDM system are met.

An upgradeable wavelength multiplexing apparatus, comprising:

• one or more fixed wavelength multiplexing modules, configured to multiplex more than one wavelength and/or more than one wavelength group;
• and
• an adjustable interleaved multiplexer, connected to the fixed wavelength multiplexing module, and configured to multiplex a signal multiplexed by the fixed wavelength multiplexing module;
• wherein the adjustable interleaved multiplexer is adjusted according to a set multiplexing parameter until requirements for a multiplexing parameter of a high-density wavelength division multiplexing (WDM) system are met.

An upgradeable wavelength demultiplexing apparatus, comprising:

• an adjustable interleaved demultiplexer, configured to interleave and demultiplex an input signal;
• and
• one or more fixed wavelength demultiplexing modules, connected to the adjustable interleaved demultiplexer, and configured to demultiplex the signal interleaved and demultiplexed by the adjustable interleaved demultiplexer;
• wherein the adjustable interleaved demultiplexer is adjusted according to a set demultiplexing parameter, until requirements for a demultiplexing parameter of a high-density WDM system are met.