Fiber-optic seismic array telemetry, system, and method
A method and system for interrogating a seismic sensor in a seismic cable having modular sensing stations spaced along the seismic cable and a connection module head end of the sensor sections, that includes dropping, at the connection modules, a wavelength of light from an input bus telemetry fiber that includes multiple wavelengths of light, distributing the dropped wavelength of light to the seismic sensor, returning the dropped wavelength from the seismic sensor to a return telemetry fiber, remultiplexing the dropped wavelength of light onto the return bus telemetry, and amplifying, in the seismic cable, the returned dropped wavelength.
1. A method of interrogating a seismic sensor in a seismic cable, the seismic cable having modular sensing stations spaced along the seismic cable and a connection module at the head end of each sensor station, the method comprising:
dropping, at the connection modules, a wavelength of light from an input bus telemetry fiber that includes multiple wavelengths of light;
distributing the dropped wavelength of light to a seismic sensor;
returning the dropped wavelength from the seismic sensor to a return telemetry fiber;
multiplexing the dropped wavelength of light onto the return bus telemetry; and
amplifying, in the seismic cable, the returned dropped wavelength.
2. A method as in claim 1 wherein the amplifying in the cable occurs in the connection modules.
3. A method as in claim 1 wherein said dropping comprises thin-film filtering.
4. A method as in claim 1 wherein said dropping comprises Bragg-grating filtering.
5. A method as in claim 1 wherein said amplifying comprises remote laser pumping.
6. A method as in claim 1 wherein said amplifying comprises local laser pumping.
7. A method as in claim 1 further comprising:
dropping a further wavelength from the input bus telemetry,
passing the dropped further wavelength to a further seismic sensor, and
multiplexing the dropped further wavelength from the further seismic sensor onto the return bus telemetry fiber before the amplifying.
8. A system of interrogating a seismic sensor in a seismic cable, the seismic cable having modular sensing stations spaced along the seismic cable and connection modules at the head end of the sensor sections, the system comprising:
means for dropping, at the connection modules, a wavelength of light from an input telemetry bus fiber that includes multiple wavelengths of light;
means for distributing the dropped wavelength of light to a seismic sensor;
means for returning the dropped wavelength from the seismic sensor to a return telemetry fiber; and
means for multiplexing and amplifying, in the seismic cable, the returned dropped wavelength on a return bus.
9. A system as in claim 8 wherein said means for amplifying is located in the connection module.
10. A system as in claim 8 wherein said means for dropping comprises a thin-film filter.
11. A system as in claim 8 wherein said means for dropping comprises a Bragg-grating filter.
12. A system as in claim 8 wherein said means for amplifying comprises a remotely pump laser signal.
13. A system as in claim 8 further comprising:
means for dropping a further wavelength from the input bus telemetry;
means for distributing the dropped further wavelength to a further seismic sensor; and
means for multiplexing the dropped further wavelength onto the return telemetry fiber before the amplifying.