E-tek Dynamics, Inc.

Oplink Communications, Inc.

Jds Uniphase Corporation

Jingyu Xu

Jing-Jong J Pan

Ming M Shih

Ronggui Shen

Mark Shi Wang

Zhimin Liu

Steven Guoxin Zhu

Weng-Herng Su

Yingzhong Shi

A four-port loop optical circulator includes a first, a second, a third and a fourth optical ports for receiving optical beam therein. The circulator further includes a plurality of optical components. The optical components include a walk-off crystal for generating a vertical optical path displacement for a vertical polarized optical beam and for passing a horizontally polarized optical beam therethrough maintaining a same optical path. The optical components also include a vertical displacement device for shifting an optical path along a vertical direction with a predefined vertical displacement for an optical beam transmitted with a particular polarization. The vertical displacement device is coupled to the walk-off crystal for guiding a beam received from the fourth port to project from the first port.

Loop optical circulator

An improved optic attenuator controllably filters an optical signal after the signal has been expanded and collimated. The optical signals are preferably expanded and refocused by a single GRIN lens, the signal passing through a variable filter between the GRIN lens and a reflector, and again between the reflector and the GRIN lens. Both the input and output fibers can be held within a single sleeve in alignment with the GRIN lens. The amount of attenuation can be indicated by a potentiometer.

Miniature variable attenuator

This invention provides a novel class of fiber-optic couplers that enable fiber-optic elements in an angled-axis alignment to be coupled in a secure and reliable manner. The fiber-optic couplers of the present invention further permit a variable gap between two successive optical elements that are coupled. This has an important practical application, for it allows GRIN lenses with a pitch less than a quarter-pitch to be employed. By cascading and/or telescoping a plurality of these fiber-optic couplers, the present invention further provides an assembly of fiber-optic systems that can be utilized as wavelength division multiplexers and de-multiplexers. An important advantage of the fiber-optic couplers of the present invention is that they allow fiber-optic elements to be arranged in various ways, yet still attaining secure and reliable coupling. Another advantage of the fiber-optic couplers of the present invention is that the coupling is less susceptible to extraneous effects such as temperature variations and moisture erosion. Further advantages of the fiber-optic couplers of the present invention include their simple assembly, versatility, and adaptability for a variety of applications.

Angled-axis fiber-optic couplers

A fiberoptic coupler capable of many functions is presented. The basic fiberoptic coupler has a first sleeve, a second sleeve, a first collimating GRIN or conventional lens, and a second collimating GRIN or conventional lens. The first sleeve holds end sections of two or more input optical fibers along the longitudinal axis of the sleeve. The second sleeve holds an end section of at least one output optical fiber. The end face of the second sleeve faces the first sleeve end face. The first collimating GRIN or conventional lens in front of the first sleeve end face collimates light signals from the input optical fibers and the second collimating GRIN or conventional lens in front of the second sleeve end face focusses light signals from at least one of the input optical fibers into the single output fiber, or at least one of the output optical fibers. With only one output fiber the coupler operates as a combiner. If more than one output fiber is held by the second sleeve, the input and output fibers can be arranged so that a light signal from one input fiber is sent to one output fiber. For added functionality, optical elements, such as isolators and wavelength-dependent filters, ca be inserted between the first and second collimating lenses.

Integrable fiberoptic coupler and resulting devices and systems

A variable optical attenuator controllably filters an optical signal after the signal has been expanded and collimated. The optical signals are optionally expanded and refocused by a single GRIN lens, the signal passing through a variable filter between the GRIN lens and a reflector, and again between the reflector and the GRIN lens. Both the input and output fibers can be held within a single sleeve in alignment with the GRIN lens. Alternatively, separate input and output GRIN lenses may be used. The amount of attenuation can be indicated by a potentiometer.

Miniature variable optical attenuator

Tuned optical filters, filter systems, and methods for tuning filters make use of a tilted filter rotated about an oblique axis of a collimating lens or other structure. This rotation varies an angle of incidence of an optical signal directed at the filter at an oblique angle to the axis of rotation. Very fine adjustments of optical filters such as for tuning a first narrow band pass filter to match a center wavelength of another narrow band pass filter, can be provided with small angles between the axis of rotation and a normal to the filter surface, and also between the axis of rotation and the optical path for the incident light. Mechanical adjustment to the filtering frequency is facilitated by making use of a rotational motion about the axis of a GRIN collimating lens.

Precision tunable optical filter

Integrable fiberoptic coupler and resulting devices and system

A fiberoptic coupler capable of many functions is presented. The basic fiberoptic coupler has a first sleeve, a second sleeve, a first collimating GRIN or conventional lens, and a second collimating GRIN or conventional lens. The first sleeve holds end sections of two or more input optical fibers along the longitudinal axis of the sleeve. The second sleeve holds an end section of at least one output optical fiber. The end face of the second sleeve faces the first sleeve end face. The first collimating GRIN or conventional lens in front of the first sleeve end face collimates light signals from the input optical fibers and the second collimating GRIN or conventional lens in front of the second sleeve end face focusses light signals from at least one of the input optical fibers into the single output fiber, or at least one of the output optical fibers. With only one output fiber the coupler operates as a combiner. If more than one output fiber is held by the second sleeve, the input and output fibers can be arranged so that a light signal from one input fiber is sent to one output fiber. For added functionality, optical elements, such as isolators and wavelength-dependent filters, can be inserted between the first and second collimating lenses.

A compact, high-performance WDM coupler which couples at least three optical fibers is presented. The coupler has the ends of first, second and third optical fibers near a first face of a collimating lens. A wavelength-dependent filter, such as a long-pass filter, a short-pass filter or a band-pass filter, is located near the opposite face of the collimating lens. The wavelength-dependent filter and the ends of the first and second optical fibers are arranged with respect to each other so that light from the first optical fiber and reflected by the wavelength-dependent filter passes into the second optical fiber. Light which passes through the wavelength-dependent filter remains collimated by the collimated lens. Reflecting elements or a second collimating lens in focus with the end(s) of one or more optical fibers can placed next to the wavelength-dependent filter and on the other side of the collimating lens to create variations of the WDM coupler for many applications.

Integrated WDM coupler devices for fiberoptic networks

A fiberoptic network transmission system combines the output signals of several laser sources into a single optical fiber. The transmission system has integrated optical isolator couplers which each have at least two input optical fibers and an output optical fiber. Each input optical fiber is connected to a laser source and the output optical fiber is connected to an input terminal of a combiner which has its output terminal connected to the single optical fiber. The integrated optical isolator couplers block light from the single optical fiber from reaching any of the laser sources.

Fiber optic network transmission system with integrated optical isolator

The present invention provides for a two-stage optical isolator with reduced polarization mode dispersion. Each stage has two birefringent polarizers separated by a Faraday rotator. The polarizers in each stage are oriented with respect to each other to operate conventionally as an optical isolator for light in a backward direction. However, the polarizers in each stage are oriented with respect to the polarizers in the other stage so that a polarization mode along one direction, say, the ordinary direction, of light in the first stage travelling toward the second stage is aligned along the opposite, extraordinary, direction in the second stage and vice versa. In this manner the component of any polarization travels the same optical distance through the optical isolator to substantially reduce polarization mode dispersion. The birefringent polarizers and Faraday rotators of multiple stages can also be fitted into a single magnet to substantially reduce the sensitivity of the optical isolator to changes in wavelength.

Dual stage optical device with low polarization mode dispersion and

The present invention provides for a two-stage optical isolator with reduced polarization mode dispersion. Each stage has two birefringent polarizers separated by a Faraday rotator. The polarizers in each stage are oriented with respect to each other to operate conventionally as an optical isolator for light in a backward direction. However, the polarizers in each stage are oriented with respect to the polarizers in the other stage so that a polarization mode along one direction, say, the ordinary direction, of light in the first stage travelling toward the second stage is aligned along the opposite, extraordinary, direction in the second stage and vice versa. In this manner the component of any polarization travels the same optical distance through the optical isolator to substantially reduce polarization mode dispersion.

Dual stage optical device with low polarization mode dispersion

Wavelength division multiplexed couplers are provided with the ends of input and output optical fibers arranged with respect to GRIN lens so that light from one input fiber is directed toward one output fiber with little crosstalk. An integrated wavelength division multiplexed coupler and isolator device useful for connecting fiberoptic amplifiers to pump lasers is also provided with one version of the WDM coupler. The integrated WDM coupler and isolator device has a tap coupler component created by a planar grating which deflects a small portion of the light through the device toward a photodetector circuit for monitoring purposes. The integrated device also may be combined with a laser diode subassembly can be combined to eliminate a pump laser connection for the fiberoptic amplifier.

Growing community of inventors

San Jose, CA, United States of America

Jingyu Xu