Reduction of the degree of polarization of a laser diode with a fiber Lyot depolarizer

Abstract

A fiber Lyot depolarizer was used to reduce the degree of polarization (DOP) of a laser pump diode. The typical DOP out of the depolarizer is better than 0.2 which should be sufficient to reduce the effect of pump polarization on erbium fiber amplifiers.Index Terms-Optical fiber amplifier, optical fiber birefringence, optical fiber device, polarization, semiconductor laser.

Scaling of the raman gain coefficient: applications to germanosilicate fibers

“…The force is thus given by (20) When the total electric field interacting with the oscillator is the sum of the pump and the scattered field, the driving force at frequency originates from products containing the electric field at the pump and signal frequency, i.e., . The relevant relation between the th component of the force and the electromagnetic field is then (21) where and are the components of the vectors and , respectively. In (21), it is assumed that the transverse parts and are independent of the direction of the electric field.…”

“…The relevant relation between the th component of the force and the electromagnetic field is then (21) where and are the components of the vectors and , respectively. In (21), it is assumed that the transverse parts and are independent of the direction of the electric field. When the force is inserted into (19), we obtain (22) where is the amplitude of the force in (21).…”

“…In (21), it is assumed that the transverse parts and are independent of the direction of the electric field. When the force is inserted into (19), we obtain (22) where is the amplitude of the force in (21). Omitting the oscillation term , we obtain from (18) the induced polarization at frequency as (23) with a complex conjugate at frequency .…”

Polarization changes at Lyot depolarizer output for different types of input beams

“…The specific situation of input beam in which the spectral components of the superposition are uniformly and completely polarized [P in r P in st P in 1] with the same state of polarization, for example, linear, and different wavelengths has been previously studied in [10][11][12][13][14][15], where uniformly polarized polychromatic beams emitted by a single source are considered. In this case, at the output of the LD, P out st is close to zero, and then the beam is locally and globally depolarized.…”

“…A device used for this purpose is the Lyot depolarizer (LD). Since the introduction of this device a long time ago [8], many theoretical and experimental works has been devoted to the study of the LD [9][10][11][12][13], and several applications have recently been proposed [14][15][16][17]. They are manufactured with two parallel synthetic crystal quartz plates assembled with their optic axes lying in the plane of the plates and forming a 45°angle (see Fig.…”