Tri-state optical device with quantum well absorption

An optical device comprising:

• first and second means including respective first and second quantumwell regions and responsive to first and second light beams, respectively, and third means responsive to an electrical voltage, for electrically controlling an optical absorption of each of said first and second quantum-well regions, the optical absorption of said first quantum-well region assuming one of first and second predetermined levels, the optical absorption of the second quantum-well region assuming the other of said first and second predetermined levels when said electrical voltage exceeds a first predetermined amount and the optical absorption of both of said first and second quantum-well regions assuming the greater of said first and second predetermined levels when said electrical voltage is less than a second predetermined amount.

An optical device comprising first and second means including respective first and second quantum-well regions and responsive to respective first and second light beams each having intensity, and third means responsive to a third light beam having intensity for electrically controlling an optical absorption of each of said first and second quantum-well regions;

• the optical absorption of said first quantum-well region assuming one of first and second predetermined levels and the optical absorption of the other of said first and second quantum-well regions assuming the other of said first and second predetermined levels when at least one of a first ratio of the intensity of the third light beam to said first light beam and a second ratio of the intensity of said third light beam to said second light beam exceeds a first predetermined amount, the optical absorption of both of said first and second quantum-well regions assuming the largest of said first and second predetermined levels when both of said first and second ratios are less than a second predetermined amount.

An optical device comprising:

• switch means having first and second states for controlling a photocurrent, and
• a bistable optical device responsive to said photocurrent and to first and second control light beams for emitting first and second output light beams having complementary power levels when a ratio of said first to said second control light beam is above a predetermined threshold and said switch means is in said first state and also for emitting said first and second output light beams both having a predetermined power level when said switch means is in said second state.