Aspects of the subject disclosure may include, for example, receiving a first optical signal from a first optical network via a first port of the wavelength converter, receiving a second optical signal from a second optical network via a second port of the wavelength converter, modulating the first optical signal with the second light signal to generate a third optical signal, eliminating the first light signal from the third optical signal to generate a fourth optical signal, and transmitting the fourth optical signal through the second optical network. The first optical signal can include a first digital signal modulated onto a first light signal of a first wavelength, the second optical signal can include a second light signal can include a second wavelength different from the first wavelength, and the fourth optical signal can include the first digital signal modulated onto the second light signal. Other embodiments are disclosed.

A Bismuth-doped fiber-optic amplifier (BDFA) system in which a Bismuth-doped optical fiber (BDF) is pumped by a fiber-laser pump (rather than by a semiconductor pump). Because higher-power fiber-laser pumps permit over-pumping of the BDF, there are benefits to the fiber-laser-pumped BDFA that cannot be realized with inherently lower-power semiconductor pumps.

Disclosed are a control method and an optical fiber amplifier. The optical fiber amplifier is configured to execute the control method. The method comprises: initially adjusting a target gain on the basis of a first offset gain to obtain the post-initial-adjustment target gain; when the actual power of the pump laser reaches target power determined on the basis of the post-initial-adjustment target gain, obtaining, on the basis of a first signal optical power and a second signal optical power, a second offset gain and a first offset slope through calculation; adjusting again the post-initial-adjustment target gain according to the second offset gain to obtain a adjusted target gain; and adjusting a target slope according to the first offset slope to obtain a adjusted target slope. This solution can provide high precision control for the gain and the slope of the optical fiber amplifier.

A power splitter may include a single-core optical fiber spliced to a multicore optical fiber with a splice diameter D.sub.sp. The single-core optical fiber and the multicore optical fiber may each include: a non-tapered portion having a cladding diameter D.sub.S or D.sub.M, and a transition portion extending from the non-tapered portion and having a transition length L.sub.TS or L.sub.TM. At least one of a taper ratio R.sub.S of the splice diameter D.sub.sp to the cladding diameter D.sub.S of the single-core optical fiber or a taper ratio R.sub.M of the splice diameter D.sub.sp to the cladding diameter D.sub.M of the multicore optical fiber may be greater than or equal to 0.05 and less than or equal to 0.4. At least one of the transition length L.sub.TS of the single-core optical fiber or the transition length L.sub.TM of the multicore optical fiber may be greater than or equal to 2 mm.