Abstract:
A method for adjusting the relative output power of individual output wavelengths of a multi-output-wavelength Raman laser (10) is disclosed. The method is characterized by the steps of suppressing the relative output power of a potentially most powerful output wavelength (98) in a first step (108), adjusting the relative output power of the shortest output wavelength (94) in a second step (110), adjusting the relative output power of further output wavelengths (96, 100, 102, 104) in a third step (112), and adjusting the relative output power of the potentially most powerful output wavelength (98) in a fourth step (114). Further, a device (68) that performs such a method is disclosed, i.e. a device for adjusting the relative output power of individual output wavelengths (94, 96, 98, 100, 102, 104) of such a laser (10).
Abstract:
The invention relates to an optical fiber amplifier device with an optical signal input and output with first piece of amplifying fiber doped with lanthanide in a double-clad structure, a second piece of amplifying fiber doped with lanthanide in a ring structure and lasers for pumping the two fiber pieces with at least one pump module.
Abstract:
Disclosed is a Raman laser device (10) having a first cavity in which lasing occurs at a first frequency, and at least one second cavity in which lasing occurs at a second frequency. Thereby respective first and second waves inside the respective cavities are generated having a first power and a second power, respectively. Further, beams propagating outside the cavities are generated by coupling out a part of the first power and a part of the second power utilizing respective output mirrors. The part of the second power that is coupled out is attenuated without attenuating the complementary part of the second power remaining in the second cavity. The Raman laser device is characterized in that the part of the second power that is coupled out is attenuated utilizing at least one Fiber Bragg Grating (46, 62).
Abstract:
A fiber amplifier comprises an amplifying double-clad fiber (DCF). The fiber has a core having a first refractive index, an inner cladding surrounding the core and having a second refractive index lower than the first refractive index and an outer cladding surrounding the inner cladding. The core is doped with Erbium (Er) and co-doped with Ytterbium (Yb), and further co-doped with Cerium (Ce). The Ytterbium (Yb) enables pump energy transfer from Ytterbium (Yb) ions being in the excited state to Erbium (Er) ions being in the ground state (4I15/2). The Cerium enables a resonant energy transfer between the Erbium (Er) excited state (4I11/2) and Cerium (Ce) ground state (4F7/2). This leads to a lower population of the Erbium 4I11/2 state and thereby increases energy transfer from Ytterbium to Erbium.
Abstract:
A cascaded Raman laser (10) has a pump radiation source (12) emitting at a pump wavelength nullp, an input section (14) and an output section (16) made of an optical medium. Each section (14, 16) comprises wavelength selectors (141, 142, . . . , 145 and 161, 162, . . . , 165) for wavelengths null1, null2, . . . , nullnnullk, where nnull3, nullp
Abstract:
The present invention relates to a cascaded multi-wavelength Raman fiber amplification stage with a length of optical fiber having input (15) and output (16) sections, pump laser means (11) for introducing pump radiation of wavelength nullp into said length of optical fiber (13), at least two pairs of reflector means (151,161; . . . ;159, 169), spaced-apart the length of optical fiber (13), at least one of said pairs of reflector means has an output reflector mean (161, 162, 163), with a reflectivity lower than 100% and a feed back loop with: a tap coupler (20) for deriving a low percentage of the optical output signal as a optical monitor signal (28), at least one wavelength selecting element (21, 25,26, 27) for the optical monitor signal (28), at least one opto-electrical converter (23, 231,232,233) generating a electrical signal and a control circuit (27) for the electrical signal connected to adjustment means (181, 182, 183) adjusting the reflectivity of the output reflector means (161, 162, 163).