Narrow band wavelength division multiplexer and method of multiplexing optical signals

A wavelength division multiplexer combining a plurality of received optical signals, said multiplexer comprising:

• at least one channel combining component for receiving optical signals transmitted through a plurality of optical channels, said channels being defined by successively different light wavelength bands associated with said channel combining component, at intervals ranging between a first channel having the lowest wavelength band to a last channel having the highest wavelength band, wherein said channel combining component combines at least one channel having a wavelength band intermediate said lowest wavelength band and said highest wavelength band with channels having said lowest and said highest wavelength bands;
• said channel combining component including
• (i) an optical circulator having at least a first port, a second port and a third port;
• (ii) an edge filter
• (a) combining optical signals in said highest and said lowest wavelength bands into combined signals, said highest and said lowest wavelength bands being above and below said intermediate wavelength band, respectively and,
• (b) providing said combined signals to said first port of said optical circulator;
• and
• (iii) at least one fiber Bragg grating, reflecting light in said highest and said lowest wavelength bands back into said second port of said optical circulator.

A wavelength division multiplexer combining a plurality of received optical signals, said multiplexer comprising:

• a channel combining component receiving optical signals transmitted through a plurality of optical channels, said channels being defined by successively different light wavelength bands at intervals ranging between a first channel having the lowest wavelength band to a last channel having the highest wavelength band, wherein said channel combining component combines at one channel having a wavelength band intermediate said lowest wavelength band and said highest wavelength band with channels having said lowest and said highest wavelength bands, wherein said lowest and said highest wavelength channels are directly adjacent to said intermediate wavelength channel;
• said channel combining component including an input port for said intermediate wavelength band and an edge filter, said edge filter
• (i) combining optical signals in said highest and said lowest wavelength bands, but not in said intermediate wavelength band, said highest and said lowest wavelength bands being situated respectively above and below said intermediate wavelength band;
• and
• (ii) providing said combined optical signals to said channel combining component.

A wavelength division multiplexer combining a plurality of received optical signals, said multiplexer comprising:

• a channel combining component receiving optical signals transmitted through only three optical channels, said channels being defined by successively different light wavelength bands at intervals ranging between a first channel having the lowest wavelength band to a last channel having the highest wavelength band, wherein said channel combining component combines at least one channel having a wavelength band intermediate said lowest wavelength band and said highest wavelength band with channels having said lowest and said highest wavelength bands, wherein said lowest and said highest wavelength channels are directly adjacent to said intermediate wavelength channel;
• said channel combining component including an input port for said intermediate wavelength band and an edge filter, said edge filter
• (i) combining optical signals in said highest and said lowest wavelength bands, but not in said intermediate wavelength band, said highest and said lowest wavelength bands being situated respectively above and below said intermediate wavelength band;
• and
• (ii) providing said combined optical signals to said channel combining component.

A wavelength division multiplexer combining a plurality of received optical signals, said multiplexer comprising:

• a channel combining component receiving optical signals transmitted through a plurality of optical channels associated with said channel combining component, said channels being defined by successively different light wavelength bands at intervals ranging between a first channel having the lowest wavelength band to a last channel having the highest wavelength band, wherein said channel combining component combines at least one channel having a wavelength band intermediate said lowest wavelength band and said highest wavelength band with channels having said lowest and said highest wavelength bands;
• said channel combining component including an optical circulator with an input port for said intermediate wavelength band and an edge filter, said edge filter
• (i) combining optical signals in said highest and said lowest wavelength bands, but not in said intermediate wavelength band, said highest and said lowest wavelength bands being situated respectively above and below said intermediate wavelength band;
• and
• (ii) providing said combined optical signals to said optical circulator.