US 5,708,734 AGranted

Polarisation-independent optical device

AssigneeKoninklijke PTT Nederland N.V.

InventorJohannes Jacobus Gerardus Maria Van Der Tol

Life of this patent

Estimating the term…

Loading patent…

Abstract

A polarisation-independent optical device for influencing the phase of an optical signal includes, in a light conductor (11), two identical adjustable phase shifters (14, 15), between which there is placed a polarisation converter (16). Optical signal components (I) entering at the input (12) of the light conductor as TE and TM polarisation modes, leave the light conductor at an output (13) as TM and TE polarisation modes having the same phase differences with respect to the signal components at the input. By way of simultaneous control of the phase shifters (14, 15) having a same modulation voltage V, there is obtained a polarisation-independent phase modulator. By including such a phase modulator in a branch of an MZ interferometer and placing, in the other branch, an identical polarisation converter, there may be realised a polarisation-independent switch or an intensity modulator.

Claims18

Dependent claims

Optical device for polarisation-independently influencing an optical signal, which device comprises:

a channel-shaped waveguide section in which optical signals propagate having signal components according to a first and a second, mutually orthogonal polarisation mode,
first phase-shifting means, operative in a first subsection of the channel-shaped waveguide section, for generating first variable phase shifts in signal components propagating in the first subsection,
second phase-shifting means, operative in a second subsection of the channel-shaped waveguide section, for generating second variable phase shifts in signal components propagating in the second subsection, and
a polarisation converter, included in the channel-shaped waveguide section between the first and the second subsection, for converting signal components propagating in the first and in the second polarisation mode into signal components propagating in the second and in the first polarisation mode, respectively, wherein the first and the second phase-shifting means are coupled, and the first and the second phase shifts are equal, at least substantially, for equal polarisation modes.

1 more element

Dependencies are inferred from the claim text.