Optical device with reduced temperature dependence
Optical apparatus with improved center wavelength temperature stability. In an embodiment, an AWG has a plurality of slots inserted along the optical paths. The slots contain one or more compensation materials which collectively correct for an order Q temperature dependency of the AWG base material. Q>=2 or the number of compensation materials is at least 2 or both.
1. Optical apparatus comprising a plurality of optical paths through a base material having a plurality of compensation regions formed therein, the compensation regions containing compensation material for compensating a thermal dependency of the base material effective index of refraction,
and wherein the compensation regions are disposed consecutively along the optical paths from a first one of the compensation regions to a last one of the compensation regions, with a spacing between corresponding points in adjacent ones of the compensation regions that varies linearly from the first one of the compensation regions to the last one of the compensation regions.
2. Apparatus according to claim 1 , wherein a particular one of the optical paths carries optical energy having a particular wavelength through the compensation regions,
and wherein the spacing variation from the first one of the compensation regions to the last one of the compensation regions is approximately equal to M times the particular wavelength, where M is an integer.
3. Apparatus according to claim 1 , wherein a particular one of the optical paths carries optical energy having a particular wavelength through the compensation regions,
and wherein the spacing variation from the first one of the compensation regions to the last one of the compensation regions is approximately equal to the particular wavelength.
4. Optical apparatus comprising:
an arrayed waveguide grating device having an output port in optical communication with an input port via an arrayed waveguide grating,
a waveguide in optical communication with a particular one of the input and output ports; and
a temperature compensation member that adjusts the physical position of the waveguide laterally with respect to the arrayed waveguide grating substantially in accordance with the function
y
=
∑
q
=
0
Q
k
q
T
q
,
Q
>=
2
,
for predetermined values of each of the k q 's and throughout a temperature range of −5 C to +70 C, all the k q being constants,
where y is the physical position of the waveguide laterally with respect to the arrayed waveguide grating, and T is temperature.
5. Apparatus according to claim 4 , wherein the arrayed waveguide grating device has an index of refraction approximated throughout the temperature range by
n=n 0 +n 1 T+n 2 T 2 ,
n 0 , n 1 and n 2 being constants,
wherein Q=2,
and wherein k 1 is related to k 2 substantially by:
k
1
k
2
=
±
n
1
g
n
2
g
.