A method of propagating a laser signal through an optical waveguide and a waveguide laser system provide a novel way of stabilizing the beam emitted by a fiber laser system above the mode instability threshold wherein the beat length of two or more interfering transverse modes of the laser signal in the optical waveguide is modulated in time.

A system (e.g., an optical amplifier) comprising gain fibers (e.g., Bismuth-doped optical fiber) for amplifying optical signals. The optical signals have an operating center wavelength (0) that is centered between approximately 1260 nanometers (1260 nm) and 1360 nm (which is in the O-Band). The gain fibers are optically coupled to pump sources, with the number of pump sources being less than or equal to the number of gain fibers. The pump sources are (optionally) shared among the gain fibers, thereby providing more efficient use of resources.

The present application is directed to an optical apparatus including an optical waveguide configured to receive an optical signal at an input wavelength. The apparatus also includes one or more optical pump sources connected to transmit pump light to the optical gain medium for the optical gain medium to amplify the optical signal. The apparatus also includes an optical feedback loop for a protection wavelength that includes the optical gain medium and at least a portion of the optical waveguide. A round-trip optical gain of the optical feedback loop is higher at an optical wavelength of the pump light than at the input wavelength less than unity in the presence of the optical signal. In addition, the round-trip gain of the optical feedback loop is greater than or equal to unity in the absence of the optical signal.

Disclosed herein is an optical fiber laser device including a seed unit for providing at least two seed lights having different wavelengths; and an amplifying unit for amplifying the at least two seed lights. The amplifying unit includes: a preamplifying unit for amplifying the at least two seed lights by using excitation light of which the wavelength is shorter than the wavelengths of the seed lights; and a final amplifying unit to which no separate excitation light source is provided. The final amplifying unit amplifies the seed light having the longest wavelength by using the other seed light as excitation light with respect to the seed light having the longest wavelength among the at least two seed light.

A fiber Raman amplifier system that includes a Raman pump module with a first pump laser at a first wavelength and a first power and a second pump laser at a second wavelength and a second power. The second wavelength is less than 10 nanometers different from the first wavelength. A ratio of the first power to the second power is adjusted to establish a Raman gain in a bandwidth.

Embodiments of the present disclosure show an optical system, with a dual-ended laser apparatus, that comprises a laser light source coupled to a controllable current drive. The dual-ended laser apparatus outputs a first light beam and a second light beam generated by the laser light source. A wavelength locker is coupled to one of the light beams, and controls the output wavelength via optical feedback signal. The system may be used to pump a fiber Raman amplifier.

According to an aspect of an embodiment, an optical amplification system may include a broadband pump source and an optical fiber doped with phosphorus. The broadband pump source may be configured to generate a pumping beam. The pumping beam may include a pumping wavelength range between 1330 nm and 1400 nm. The optical fiber may be configured to receive the pumping beam and an input optical signal. The input optical signal may include a first component that may correspond to a first wavelength range and a second component that may correspond to a second wavelength range. The pumping beam may cause Raman amplification to the first component and the pumping beam may cause Raman amplification to the second component. The amplification of the first component and the second component by the pumping beam may produce an amplified optical signal.

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.