Dispersion compensation apparatus
View Patent ↗A dispersion compensation apparatus employing an arrayed-waveguide-grating (AWG) which exhibits a dispersion slope.
1. An optical dispersion compensation apparatus comprising:
a first slab waveguide;
a second slab waveguide;
an arrayed waveguide grating (AWG) having a plurality of waveguide arms optically connecting the first slab waveguide to the second slab waveguide;
CHARACTERIZED IN THAT
each waveguide arm of the AWG exhibits a path length L(m) which is defined by a quantized parabolic component.
2. The optical apparatus of claim 1 further CHARACTERIZED IN THAT:
each waveguide arm of the AWG exhibits a path length L(m), which is defined by the following relationship:
L
(
m
)
=
λ
0
n
{
Am
+
round
[
γ
(
m
-
M
+
1
2
M
-
1
2
)
2
]
}
where
round is a function that rounds its argument to the nearest integer;
A is the grating order of the AWG;
m is the waveguide arm;
M is the total number of waveguide arms;
n is the refractive index of the waveguide arms;
λ 0 is a center vacuum wavelength; and
γ sets a desired dispersion slope.
3. The optical apparatus of claim 2 further comprising:
an input/output waveguide optically connected to an input port of the first slab waveguide; and
one or more mirrors, positioned at an output side of the second slab waveguide such that light entering the apparatus via the input/output waveguide, exits the apparatus via the input/output waveguide having a desirable amount of any accumulated dispersion compensated.
4. The optical apparatus of claim 3 further comprising:
one or more lenses, interposed between the AWG and the mirrors.
5. The optical apparatus of claim 3 further comprising a circulator, optically connected to an input waveguide, an output waveguide and the input/output waveguide such that light traversing the input waveguide is directed into the input/output waveguide through the effect of the circulator and light exiting the input/output waveguide into the circulator is directed into the output waveguide through the effect of the circulator.
6. Dispersion compensation apparatus comprising:
an input/output waveguide;
a first free space region connected to the input/output waveguide;
an optical grating connected to the first free space region, the grating including a plurality of unequal length waveguides;
a second free space region connected to the grating; and
one or more mirrors, positioned opposite to the grating relative to the second free space region such that light entering the second free space region via the grating is reflected back into the grating through the effect of the mirrors;
said dispersion compensation apparatus
CHARACTERIZED IN THAT
the length of each one of the waveguides comprising the optical grating is defined by a quantized parabolic component.
7. The dispersion compensation apparatus of claim 6 further CHARACTERIZED IN THAT:
each waveguide arm of the AWG exhibits a path length L(m), which is defined by the following relationship:
L
(
m
)
=
λ
0
n
{
Am
+
round
[
γ
(
m
-
M
+
1
2
M
-
1
2
)
2
]
}
where
round is a function that rounds its argument to the nearest integer;
A is the grating order of the AWG;
m is the waveguide arm;
M is the total number of waveguide arms;
n is the refractive index of the waveguide arms;
λ 0 is a center vacuum wavelength; and
γ sets a desired dispersion slope.
8. The optical apparatus of claim 7 further comprising:
one or more lenses, interposed between the AWG and the mirrors.
9. A method of providing a desired amount of dispersion compensation to an optical signal traversing an optical apparatus having a first and second free space region, an optical grating coupled therebetween, the grating including a plurality of unequal length waveguides, and the optical apparatus having a bidirectional input/output waveguide coupled to the first free space region and one or more mirrors reflective to light entering the second free space region, the method comprising the steps of:
configuring the lengths of the grating waveguides such that each exhibits a length which is defined by a quantized parabolic component; and
introducing light into the apparatus, said light exhibiting an amount of dispersion, such that the light enters via the bidirectional input/output waveguide, traverses the first free space region, the optical grating, and the second free space region where it is reflected back through the second free space region, the optical grating and the first free space region and exits via the input/output waveguide having a desirable amount of the dispersion compensated.
10. The method of claim 9 further comprising the step of:
configuring each waveguide arm of the AWG is to exhibits a path length L(m), which is defined by the following relationship:
L
(
m
)
=
λ
0
n
{
Am
+
round
[
γ
(
m
-
M
+
1
2
M
-
1
2
)
2
]
}
where
round is a function that rounds its argument to the nearest integer;
A is the grating order of the AWG;
m is the waveguide arm;
M is the total number of waveguide arms;
n is the refractive index of the waveguide arms;
λ 0 is a center vacuum wavelength; and
γ sets a desired dispersion slope.
11. The method of claim 10 further comprising the step of:
refracting, light traversing the second free space region through the effect of one or more lenses positioned in the free space region between the grating and the mirrors.