Thermally compensated variable optical attenuator with displacement mechanism

A device for variably attenuating an optical signal transmitted through the device comprising:

• a frame;
• a flexure exhibiting flexibility in a first orthogonal direction and rigidity in a second orthogonal direction;
• a fixed portion of the flexure being attached to the frame and a free portion of the flexure being suspended from a resilient portion of the flexure;
• a fiber optical coupler having first and second fiber sections joined together by an fiber intermediate section;
• the first fiber section being attached to the frame;
• the second fiber section being supported by the free portion of the flexure;
• an actuator operatively engaged with the free portion of the flexure for displacing the free portion of the flexure with respect to the fixed portion of the flexure through a range of displacement positions in the first orthogonal direction;
• and
• the second fiber section of the coupler being displaceable together with the free portion of the flexure for bending the intermediate fiber section of the coupler and attenuating the optical signal as a continuous function of the amount of bending in the intermediate fiber section of the coupler.

A thermally compensated device for variably attenuating optical signals transmitted through the device comprising:

• a frame;
• an optical attenuator having first and second relatively displaceable sections for attenuating the optical signals as a function of relative displacement;
• the first section of the attenuator being attached to the frame;
• the second section of the attenuator being supported for movement with respect to the frame;
• a source of motion attached to the frame;
• a kinematic chain connecting the source of motion to the second section of the attenuator for displacing the second section with respect to the first section of the attenuator through a range of relative displacement positions;
• the first section of the attenuator being spaced from the source of motion through a first distance that varies as a function of temperature;
• the second section of the attenuator being spaced from the source of motion through a second distance that varies as a function of both temperature and the relative displacement;
• portions of the second distance contributed by the relative displacement not significantly varying as a function of temperature;
• and
• throughout the range of displacement positions, the distances between the first and second sections of the attenuator and the source of motion varying by substantially the same amounts as a function of temperature so that the relative displacement positions remain substantially independent of temperature.

A thermally compensated device for variably attenuating an optical signal transmitted through the device comprising:

• a frame;
• an optical coupler having a first fiber section, a second fiber section, and an intermediate fiber section interconnecting the first and second fiber sections;
• the first fiber section being attached to the frame;
• the second fiber section being supported for movement with respect to the frame;
• a source of motion attached to the frame;
• a kinematic chain connecting the source of motion to the second fiber section;
• the kinematic chain including among a series of components a cam having a dimension that varies as a function of position section for displacing the second fiber section with respect to the first fiber section through a range of displacement positions;
• and
• a portion of the cam embodying the variation in dimension being made of a material having a lower coefficient of thermal expansion than other of the components of the kinematic chain.