Monitorable hollow core optical fiber

1. A monitorable hollow core (HC) optical fiber apparatus comprising:

one or more monitorable HC optical fibers configured to transmit optical signals, each monitorable HC optical fiber comprising one or more hollow core anti-resonant fiber (HC-ARF) segments and one or more monitoring segments alternatingly connected with the HC-ARF segments, each monitoring segment comprising one or more non-HC-ARF constituents,

wherein each monitoring segment enables a monitoring device to monitor one or more optical properties of the monitorable HC optical fiber using interactions between one or more of the optical signals and the one or more non-HC-ARF constituents, wherein at least one of the monitoring segments is connected to an adjacent one of the HC-ARF segments via a transition segment having a different mode field radius (MFR).

2. The apparatus as claimed in claim 1 , wherein a sum of propagation losses and connection losses incurred in each monitorable HC optical fiber is lower than an expected propagation loss of a conventional solid core (SC) optical fiber having a length identical to a length of the monitorable HC optical fiber.

3. The apparatus as claimed in claim 1 , further comprising the monitoring device, wherein the monitoring device is capable of monitoring the one or more optical properties using optical time domain reflectometry (OTDR) measurements or pump-probe measurements or both.

4. The apparatus as claimed in claim 1 , wherein the one or more optical properties comprise one or more of scatter, loss, wavelength-dependent power, wavelength-dependent dispersion, polarization-dependent loss (PDL), and polarization-mode dispersion (PMD).

5. The apparatus as claimed in claim 1 , wherein each monitorable HC optical fiber comprises a plurality of the monitoring segments at a respective plurality of different locations in the monitorable HC optical fiber.

6. The apparatus as claimed in claim 1 , wherein the transition segment comprises a plurality of transition subsegments having a respective plurality of different MFR values.

7. The apparatus as claimed in claim 1 , comprising a plurality of the monitorable HC optical fibers and a protective conduit housing the plurality of monitorable HC optical fibers.

8. The apparatus as claimed in claim 1 , comprising one or more optical amplifiers configured to amplify the optical signals transmitted on the one or more monitorable HC optical fibers.

9. The apparatus as claimed in claim 8 , wherein at least one of the monitorable HC optical fibers comprises a proximal monitoring segment located at a proximal end of the monitorable HC optical fiber and a distal monitoring segment located at a distal end of the monitorable HC optical fiber, wherein an output of one of the optical amplifiers is connected to the proximal monitoring segment, and wherein an input of another one of the optical amplifiers is connected to the distal monitoring segment.

10. A method for monitoring a monitorable hollow core (HC) optical fiber, the method comprising:

transmitting one or more first optical signals on the monitorable HC optical fiber, wherein the monitorable HC optical fiber comprises one or more HC anti-resonant fiber (HC-ARF) segments and one or more monitoring segments alternatingly connected with the HC-ARF segments, each monitoring segment comprising one or more non-HC-ARF constituents, and wherein at least one of the monitoring segments is connected to an adjacent one of the HC-ARF segments via a transition segment having a different mode field radius (MFR);

responsive to transmitting the one or more first optical signals, detecting one or more second optical signals on the monitorable HC optical fiber, the one or more second optical signals being primarily dependent on interactions between the one or more first optical signals and the non-HC-ARF constituents of the monitoring segments; and

monitoring one or more optical properties of the monitorable HC optical fiber using the one or more first optical signals and the one or more second optical signals.

11. The method as claimed in claim 10 , wherein a quantity and respective properties of the one or more monitoring segments are selected such that a sum of propagation losses and connection losses incurred in the monitorable HC optical fiber is lower than an expected propagation loss of a conventional solid core (SC) optical fiber having a length identical to a length of the monitorable HC optical fiber.

12. The method as claimed in claim 10 , wherein the one or more optical properties are monitorable using optical time domain reflectometry (OTDR) measurements.

13. The method as claimed in claim 12 , further comprising comparing OTDR measurements taken at two or more different times.

14. The method as claimed in claim 10 , wherein the one or more optical properties are monitorable using pump-probe measurements.

15. The method as claimed in claim 12 , wherein the one or more optical properties comprise one or more of scatter, loss, wavelength-dependent power, wavelength-dependent dispersion, polarization-dependent loss (PDL), and polarization-mode dispersion (PMD).

16. The method as claimed in claim 10 , wherein the monitorable HC optical fiber comprises a plurality of the monitoring segments enabling monitoring of the one or more optical properties at a respective plurality of different locations in the monitorable HC optical fiber.

17. A method for manufacturing a monitorable hollow core (HC) optical fiber apparatus, the method comprising:

providing one or more hollow core anti-resonant fiber (HC-ARF) segments of a monitorable HC optical fiber;

providing one or more monitoring segments of the monitorable HC optical fiber, each monitoring segment comprising one or more non-HC-ARF constituents;

alternatingly connecting the HC-ARF segments with the monitoring segments to form the monitorable HC optical fiber, wherein the connecting comprises connecting at least one of the monitoring segments to an adjacent one of the HC-ARF segments via a transition segment having a different mode field radius (MFR),

wherein one or more optical properties of the monitorable HC optical fiber are monitorable using interactions between one or more optical signals transmitted on the monitorable HC optical fiber and the non-HC-ARF constituents of the monitoring segments.

18. The method as claimed in claim 17 , further comprising selecting a quantity and respective properties of the monitoring segments such that a sum of propagation losses and connection losses incurred in the monitorable HC optical fiber is lower than an expected propagation loss of a conventional solid core (SC) optical fiber having a length identical to a length of the monitorable HC optical fiber.

19. The method as claimed in claim 17 , wherein the connecting comprises mechanical splicing.

20. The method as claimed in claim 17 , further comprising:

forming the transition segment by connecting together a plurality of transition subsegments having a respective plurality of different MFR values.