Optical multiplexer and demultiplexer

An optical demultiplexer comprising a plurality of flat optical filter means each of which transmits a different predetermined wavelength and reflects other wavelengths, said optical filter means being arranged substantially in a pair of spaced parallel rows, the filter means in the first row being staggered in relation to the corresponding filter means in the second row so that an optical beam is transmitted or reflected by said optical filter means in sequence;

• an optical means for applying a collimated input optical beam to each of said optical filter means with a small angle of incidence;
• and another optical means confronting each of said optical filter means to receive and focus the transmitted beam from each optical filter means for illuminating a light detector.

An optical multiplexer comprising a transparent dielectric substrate having first and second parallel planes, a first group of optical filters positioned linearly on said first plane, a second group of optical filters positioned linearly on the second plane and staggered in relation to the corresponding filters on the first plane, projecting means for projecting collimated optical beams to each of said optical filters at a predetermined angle of incidence, and coupling means provided at the output of the final optical filter to connect the output optical beam to an outside optical fiber, wherein each said optical filter transmits a wave having a different predetermined wavelength and reflects waves having other wavelengths.

An optical demultiplexer comprising a transparent dielectric substrate having first and second parallel planes, a first group of optical filters positioned linearly on said first plane, a second group of optical filters positioned linearly on the second plane and staggered in relation to the corresponding filters on the first plane, projecting means for projecting the collimated optical beam to the first optical filter at a predetermined angle of incidence, and at least one light detector provided behind each optical filter, wherein each said optical filter transmits a wave having a different predetermined wavelength and reflects waves having other wavelengths.