Passively temperature-compensated wavelength-tunable device comprising flexed optical gratings and communication systems using such devices

Abstract

In accordance with the invention, a passively temperature-compensated tunable optical grating device comprises a grating, which is fixed at both ends to a support frame, and is mechanically or magnetically flexed so that a tensile strain induced in the grating reconfigures the resonant wavelength of the grating. Preferred embodiments include at least one waveguide grating, a flexing mechanism capable of inducing a latchable change in grating periodicity and at least one negative thermal expansion component which, upon heating, reduces the strain in the grating so that the temperature-induced wavelength shift is substantially cancelled out. The device can reduce the temperature-dependent wavelength change to less than 0.5 nm/100 deg. C, and preferably less than 0.05 nm/100 deg. C. In a preferred embodiment, the packaging assembly also includes a fine-wavelength adjusting mechanism for post-assembly corrective tuning. The device is especially useful in WDM communication systems, particularly for adding or dropping channels, for dynamically gain-equalizing optical amplifiers, for tunable lasers, and for dispersion compensation.

Dependencies are inferred from the claim text.