Polarization-independent optical switch/attenuator

An optical device for connection to an input optical fiber and an output optical fiber, said device having at least one control terminal, said device controlling the strength of an optical signal from said input fiber to said output fiber responsive to a signal on said control terminal, said device comprising

• a first GRIN lens arranged to collimate said optical signal from said input optical fiber;
• a first birefringent lithium niobate polarizer having an optical axis perpendicular to a line of travel from collimated optical signal from said first GRIN lens, said first polarizer arranged to split said optical signal from said first GRIN into two polarization modes;
• a second birefringent lithium niobate polarizer having an optical axis perpendicular to said line of travel from collimated optical signal from said first GRIN lens and offset from said optical axis of said first polarizer by a predetermined angle;
• a second GRIN lens arranged to recollimate said optical signal from said second polarizer to said output fiber;
• and
• a liquid crystal cell, disposed between said first and second polarizers and connected to said control terminal, for controllably rotating said optical signal from said optical axis of said first polarizer toward said optical axis of said second polarizer responsive to said signal on said control terminal;
• whereby performance of said device is independent of polarization of said optical signal in said input fiber.