Oplink Communications, Inc.

U.s.a. Kaifa Technology, Inc.

Wei-Zhong Li

Qingdong Guo

Feng Quan Liu

Vincent Au-Yeung

Qing-Dong Guo

Wenhui Wang

Mark Shi Wang

Wei Luo

Qing Shao

Yanfeng Yang

Haiguang Lu

An optical switch includes a first port, a second port, a first component group, a second component group, and a switching component group. The switching component group includes a reflector, a polarization beam splitter coupled to the reflector, and a polarization switch coupled to the polarization beam splitter. The first component group is coupled between the first port and the reflector in the switch component group. The second component group is coupled between the second port and the polarization beam splitter in the switch component group.

Method and apparatus for optical switching

An optical depolarizer includes a birefringent block, a reflector coupled to the block, a first input port for providing polarized light to the block and an output port configured to receive polarized light from the block. The depolarizer optionally includes a non-reciprocal combination-device having a principal direction and including a first birefringent wedge, a second birefringent wedge, and a non-reciprocal rotating element. The non-reciprocal rotating element can be a Faraday rotator. The birefringent block can be optically coupled to the non-reciprocal combinatoin device. The optical depolarizer can include a lens that is optically coupled to the first wedge. The optical depolarizer can include a capillary for holding at least a PM optical fiber and an output optical fiber.

Depolarizer

An optical isolator includes a non-reciprocal combination-device and a reflector. The non-reciprocal combination-device has a principal direction and includes a first birefringent wedge, a second birefringent wedge, and a non-reciprocal rotating element. The non-reciprocal rotating element can be a Faraday rotator. The reflector is positioned proximate to the second birefringent wedge, for reflecting light exiting from the non-reciprocal combination-device in the principal direction to reenter the non-reciprocal combination-device in a reverse principal direction. The optical isolator can include a lens that is optically coupled to the first wedge. The optical isolator can include a capillary for holding an input PM optical fiber and an output PM optical fiber. The optical isolator can also include a capillary for holding at least two input PM optical fibers and an output optical fiber.

Optical isolator

A variable optical attenuator includes a first lens, a MEMS device, a second lens, and a wedge. The first lens is configured to collimate an input light received on a first port and focus an output light on a focus point proximate to a second port. The MEMS device includes a reflection surface having a tilting angle thereof controllable by a control variable. The second lens has a focus point positioned proximate to the reflection surface of the MEMS device. The wedge is positioned between the first lens and the second lens and is configured to refract the input light received from the first lens to enter the second lens and refract the output light received from the second lens to enter the first lens.

Variable optical attenuator with MEMS devices

An integrated optical fiber amplifier system includes a non-reciprocal combination-device and an optical fiber amplifier. The non-reciprocal combination-device includes a first birefringent wedge, a second birefringent wedge, and a non-reciprocal rotating element. The optical fiber amplifier is optically coupled to the first birefringent wedge for receiving a combined pump light from the non-reciprocal combination-device.

Integrated two-pump combiner for optical fiber amplifiers

An extendable four-port circulator includes a middle birefringent crystal, a first birefringent crystal, a first non-reciprocal device, a second birefringent crystal, and a second non-reciprocal device. The first non-reciprocal device is coupled to the first birefringent crystal. The second non-reciprocal device is coupled to the second birefringent crystal. The middle birefringent crystal includes a first surface, a second surface, a third surface, and a fourth surface. The first surface is coupled to the first non-reciprocal device. The second surface is coupled to the second non-reciprocal device. The third surface defines first and second extension interfaces. The fourth surface defines third and fourth extension interfaces. A multi-port circulator includes at least one extendable four-port circulator.

Multi-port circulator

A four-port circulator includes a first birefringent crystal, a structured polarization rotator, a first birefringent wedge, a second birefringent crystal, a non-reciprocal device, and a second birefringent wedge. The structured polarization rotator is coupled to the first birefringent crystal. The first birefringent wedge is coupled to the structured polarization rotator. The second birefringent crystal is coupled to the first birefringent wedge. The non-reciprocal device is coupled to the second birefringent crystal. The second birefringent wedge is coupled to the non-reciprocal device.

Four-port PM circulator

A three-port circulator includes a non-reciprocal rotating element, a first birefringent wedge, and a second birefringent wedge. The non-reciprocal rotating element has a rotation axis and rotates the polarization of light passing through it by an predetermined angle. The first birefringent wedge has a first optical axis substantially perpendicular to the rotation axis. The second birefringent wedge has a second optical axis substantially perpendicular to both the rotation axis and the first optical axis. The second birefringent wedge is optically coupled between the non-reciprocal rotating element and the first birefringent wedge.

Three-port circulator

An optical system provides reflection-type isolation, and may include variable optical attenuation and/or a tap monitor. The optical system may include an optical isolator with a beam splitter such as a walk-off plate, a focusing element such as a GRIN lens, a combiner comprising two birefringent wedges and a non-reciprocal rotating device such as a Faraday rotator, a compensation device, and a reflector. The Faraday rotator may be variable to provide variable attenuation. The reflector may be a partial reflector to provide a tap monitor. The optical system is configured so that light transmitted into the optical isolator through the input fiber may be transmitted out of the optical isolator through the output fiber, but light transmitted into the optical isolator through the output fiber is generally not transmitted out of the optical isolator through the input fiber.

An optical device includes non-reciprocal combination-device and a polarizer. The non-reciprocal combination-device has a principal direction and a reverse principal direction. The non-reciprocal combination-device includes a first birefringent wedge, a second birefringent wedge, and a non-reciprocal rotating element. The polarizer receives a first light signal from the second birefringent wedge traveling in the principal direction and transmits a second light signal to enter the second birefringent wedge in the reverse principal direction.

Three-port PM circular having isolation function

An optical depolarizer includes a non-reciprocal combination-device, a birefringent block, and a reflector. The non-reciprocal combination-device has a principal direction and includes a first birefringent wedge, a second birefringent wedge, and a non-reciprocal rotating element. The non-reciprocal rotating element can be a Faraday rotator. The birefringent block is optically coupled to the second birefringent wedge. The reflector is optically coupled to the birefringent block. The optical depolarizer can include a lens that is optically coupled to the first wedge. The optical depolarizer can include a capillary for holding at least a PM optical fiber and an output optical fiber.

In another aspect, the invention provides a closed loop optical circulator including a first crystal for splitting an input light signal into two components, a second crystal for deflecting the two components received from the first crystal in a direction if the two components have a first polarization, a third crystal for deflecting the two components received from the second crystal in an opposite direction if the two components have the first polarization, and a fourth crystal for joining the two components received from the third crystal.

Method and system for providing an optical circulator

This invention presents a novel tunable module that can be incorporated in various optical devices, to provide a tunability and selectivity in a characteristic of an optical signal by effectively modifying its optical path lengths. The present invention also provides an optical isolator that incorporates such a tunable module, so that polarization mode dispersion is minimized to an arbitrarily low level. The present invention further describes methods for incorporating the tunable module in optical devices and for tuning the optical characteristics.

Optical isolators with ultra-low polarization mode dispersion

A polarization splitter and combiner for processing a beam containing a first polarization and a second polarization to spatially separate these polarizations by using a birefringent element for receiving the beam and walking off the first polarization from the second polarization by an initial walk-off distance. A first lensing element with an optical axis is oriented to admit the first polarization at a first input point and output the first polarization at a first output angle to the optical axis and the second polarization at a second output angle to the optical axis. A second lensing element positioned after the first lensing element is oriented to receive the polarizations at input angles equal to their respective output angles, and outputs both polarizations at a first and second output point respectively. In a symmetrical arrangement, the first and second output points are separated by the initial walk-off distance. Additional walk-off control elements and optics can be interposed between the first and second lensing elements, depending on the functionality of the beam splitter and combiner or optical device employing the same.

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San Jose, CA, United States of America

Wei-Zhong Li