Method and apparatus for multiplexing multiple Sagnac interferometers with single input for source light

An inertial measurement system comprising:

• an optical light wave source for establishing at least a single optical light wave;
• and
• a first directional coupler that splits said at least single optical light wave into a second light beam and a third light beam, said first directional coupler coupled to supply light from said second light beam to a first Sagnac interferometer of a plurality of Sagnac interferometers and from said third light beam to a second directional coupler, and also coupled to deliver light from said first directional coupler returning from said first Sagnac interferometer to a first detector of a plurality of detectors that indicates rotation of said first Sagnac interferometer;
• and
• said second directional coupler receives and splits said third light beam into a fourth light beam and a fifth light beam, and supplies light from said fourth light beam to a second Sagnac interferometer and delivers light from said second directional coupler returning from said second Sagnac interferometer to a second detector, where said second detector provides a signal indicative of rotation of o-n-ly said second Sagnac interferometer.

A method of transmitting source light to supply light to a plurality of Sagnac interferometers comprising:

• a plurality of directional couplers each consisting of four ports;
• coupling said source light into a first port of a first directional coupler to split said source light into a second light beam that emerges from a second port of said first directional coupler and a third light beam that emerges from a third port of said first directional coupler and supplying light from said second light beam to a first Sagnac interferometer and supplying light from said third light beam to a first port of a second directional coupler;
• further supplying light returning from said first Sagnac interferometer to said second port of said first directional coupler to split said returning light into a fourth light beam that emerges from said first port of said first directional coupler and a fifth light beam that emerges from a fourth port of said first directional coupler and supplying said fifth light beam to a first detector and operating said first detector to provide a signal indicative of rotation of said first Sagnac interferometer;
• and
• coupling said third light beam into said first port of said second directional coupler that splits said third light beam into a sixth light beam that emerges from a second port of said second directional coupler and a seventh light beam that emerges from a third port of said first directional coupler, supplying light from said sixth light beam to a second Sagnac interferometer and supplying light returning from said second Sagnac interferometer to said second port of said second directional coupler to split said returning light into an eighth light beam that emerges from said first port of said second directional coupler and a ninth light beam that emerges from a fourth port of said second directional coupler and supplying said ninth light beam to a second detector, and operating said second detector to provide a signal indicative of rotation of said second Sagnac interferometer.