A sensing cable includes a first optical fiber, a second optical fiber that extends along the first optical fiber and that is spaced from the first optical fiber, and a transmitting material that includes an intervention portion present between the first optical fiber and the second optical fiber, the transmitting material being configured to transmit light from the first optical fiber to the second optical fiber through the intervention portion.

An optical fiber may include a core region and a cladding region surrounding the core region. The cladding region may include an inner cladding region surrounding the core region, a depressed-index cladding region surrounding the inner cladding region, and an outer cladding region surrounding the depressed-index cladding region. The inner cladding region may include a thickness greater than or equal to 1 m. The depressed-index cladding region may include a first region and a second region, wherein a relative refractive index of the depressed-index cladding region may decrease monotonically with increasing radius in the first region, and wherein the relative refractive index of the depressed-index cladding region may be substantially constant in the second region. The optical fiber may achieve low microbend loss with large mode field diameter, while also maintaining low macrobend loss, low cable cutoff, and/or a zero dispersion wavelength between 1300 nm and 1324 nm.