Abstract: An operation unit of a PMD compensation module includes a PBS (polarization beam splitter), a compensating part and a combiner. The PBS separates an optical input into a first polarized signal and a second polarized signal. The compensating part includes a fixed prism and a movable prism. The first polarized signal outputted from the PBS travels through the fixed prism and the movable prism in series. The light path of the first polarized signal in the movable prism is elongated or shortened according to a position of the movable prism. A continuously variable delay can thus be applied between the first and second polarized signals. The combiner recombines the first polarized signal received from the compensating part and the second polarized signal received from the PBS into an optical output signal.

Abstract: An optical add-drop multiplexer successively comprises a first ferrule, a first graded index (GRIN) lens with a bandpass filter attached thereon, an optical crystal, a second GRIN lens, and a second ferrule. An input and an output optical fiber are stationed in the first ferrule, and a dropping and an adding optical fiber are stationed in the second ferrule. An optical multiplexed signal from the input optical fiber is transmitted through the first GRIN lens to the bandpass filter. From the bandpass filter, an optical signal having a wavelength identical to a central wavelength of the bandpass filter is output to the dropping optical fiber, and other optical signals having other wavelengths are coupled with an optical signal from the adding optical fiber having a wavelength identical to the central wavelength of the bandpass filter and are transmitted to the output optical fiber.

Abstract: An optical switch (10) in accordance with the present invention includes a first PBS (101), a second PBS (104), two reflective elements (102, 105) and two liquid crystal elements (103, 106). The first PBS splits input light into two polarized beams, said two beams being orthogonally polarized with respect to each other. The two beams each respectively pass through a different liquid crystal element and a reflective element. The polarization state of the passed beams can be controlled by the electrified or unelectrified state of the liquid crystal elements. The two beams are combined into one output beam by the second PBS, and are outputted from a selected output port (13, 14) depending on the state of electrification of the liquid crystal elements.

Abstract: An improved wavelength division multiplexing (WDM) coupler includes a dual fiber collimator assembly (27), a filter device (29), and a single fiber collimator assembly (31). The filter device comprises a holder (26) and a filter (24) received therein. The holder has a first opening (21) and a second opening (23) communicating therewith. The holder firmly secures both the dual fiber collimator assembly and the single fiber collimator assembly therein. A relative position and orientation of a first GRIN lens (22) and the filter can be adjusted during assembly by sliding the first GRIN lens in or out of and by microtilting the GRIN lens in the second opening while monitoring reflection insertion loss. A DWM coupler which is more easily adjusted during assembly and which has a more stable structure is thus obtained.

Abstract: A high reflection isolation device includes a metal tube (1), a glass tube (2) enclosed by the metal tube, a dual fiber pigtail (DFP) (3) having a first fiber (30) and a second fiber (32), a GRIN lens (4) engaging with the metal tube via an adhesive (7), a first filter (5) mounted on the GRIN lens, and a second filter (6) mounted between the dual fiber pigtail and the GRIN lens. Light input from the first fiber passes through the GRIN lens and encounters the first filter. The first filter passes only a first wavelength of light and reflects all others, which pass back through the GRIN lens to the second filter. The second filter passes only a second wavelength of light, which is transmitted into the second fiber.

Abstract: An optical add-drop multiplexer (OADM) apparatus (10) includes an input/output channel (100), a drop channel (200), an add channel (300) and an optical filter (500). Light signals having a specific wavelength are transmitted from an input fiber (101) and pass through the input/output channel, the specific wavelength of the light signals passes through the filter and the drop channel and goes into a drop fiber (201). Another light signal having the specific wavelength is transmitted from an add fiber (302), passes through the add channel and the filter, and combines with the reflected wavelengths of the light signals, and the combined wavelengths pass through the input/output channel and go into an output fiber (102).

Abstract: A piezoelectric tunable filter (10) includes a ring (12) made of piezoelectric material surrounding a thin film waveguide (14), and an actuator (17) surrounding the ring. The actuator generates acoustic waves which apply external radial forces on the ring. Because the ring has piezoelectric properties, a periodic, high frequency piezoelectric signal can be generated by the ring and input to the waveguide to produce lattice vibration of the waveguide. The vibration can generate a fluctuating pattern of refractive index in the thin film waveguide due to the modulating effect of the signal. Thus, a periodic radial force of a predetermined frequency produces a desired vibration of the thin films of the waveguide, which in turn produces a desired refractive index in each film, which accordingly changes an optical thickness of each film.

Abstract: An optical switch (10) includes an input device (11), a reflection output device (12), a transmission output device (13), a prism (2) and a rotation device (3). The input and reflection output devices are rotatable around the prism between a first position and a second position. The prism has a reflective surface (21) to effect optical switching. When the input and reflection output devices are at a first position, an input light beam from the input device passes through the reflective surface of the prism, and is output through the transmission output device. When the input and reflection output devices are at a second position, the input light beam from the input device is incident on the reflective surface of the prism at an angle which is equal to or larger than a critical angle of the prism. The input light beam is totally reflected by the reflective surface of the prism and is output through the reflection output device.

Abstract: An improved wavelength division multiplexing (WDM) coupler includes a dual fiber collimator assembly (27), a filter device (29), and a single fiber collimator assembly (31). The filter device comprises a holder (26) and a filter (24) received therein. The holder has a first opening (21) and a second opening (23) communicating therewith. The holder firmly secures both the dual fiber collimator assembly and the single fiber collimator assembly therein. A relative position and orientation of a first GRIN lens (22) and the filter can be adjusted during assembly by sliding the first GRIN lens in or out of and by microtilting the GRIN lens in the second opening while monitoring reflection insertion loss. A DWM coupler which is more easily adjusted during assembly and which has a more stable structure is thus obtained.

Abstract: A polarized illumination system (10) in accordance with the present invention includes an illumination device (1) for emitting light beams and a polarizing device (2) aligned with the illumination device. The polarizing device has a first micro lens array (21), a second micro lens array (22), a birefringent crystal (23), and a plurality of half wave retardation plates (24) arranged in order. The birefringent crystal splits light beams into two, orthogonally polarized components, and the half wave retardation plates convert the polarization state of one of those components to match the state of the other component. The half wave retardation plates are attached to one side of the birefringent crystal. The structure of the polarized illumination system has low cost and high light utilization efficiency.

Abstract: An optical add-drop multiplexer (OADM) apparatus (10) includes an input/output channel (100), a drop channel (200), an add channel (300) and an optical filter (500) light signals having a specific wavelength are transmitted from an input fiber (101) and pass through the input/output channel, the specific wavelength of the light signals passes through the filter and the drop channel and goes into a drop fiber (201). Another light signal having the specific wavelength is transmitted from a add fiber (302) passes through the add channel and the filter, and combines with the reflected wavelengths of the light signals, the combined wavelengths pass through the input/output channel and go into the output fiber (102).

Abstract: An optical switch (10) in accordance with the present invention includes a first PBS (101), a second PBS (104), two reflective elements (102, 105) and two liquid crystal elements (103, 106). The first PBS splits input light into two polarized beams, said two beams being orthogonally polarized with respect to each other. The two beams each respectively pass through a different liquid crystal element and a reflective element. The polarization state of the passed beams can be controlled by the electrified or unelectrified state of the liquid crystal elements. The two beams are combined into one output beam by the second PBS, and are outputted from a selected output port (13, 14) depending on the state of electrification of the liquid crystal elements.

Abstract: A piezoelectric tunable filter (10) includes a ring (12) made of piezoelectric material surrounding a thin film waveguide (14), and an actuator (17) surrounding the ring. The actuator generates acoustic waves which apply external radial forces on the ring. Because the ring has piezoelectric properties, a periodic, high frequency piezoelectric signal can be generated by the ring and input to the waveguide to produce lattice vibration of the waveguide. The vibration can generate a fluctuating pattern of refractive index in the thin film waveguide due to the modulating effect of the signal. Thus, a periodic radial force of a predetermined frequency produces a desired vibration of the thin films of the waveguide, which in turn produces a desired refractive index in each film, which accordingly changes an optical thickness of each film.

Abstract: An optical switch (10) includes an input device (11), a reflection output device (12), a transmission output device (13), a prism (2) and a rotation device (3). The input and reflection output devices are rotatable around the prism between a first position and a second position. The prism has a reflective surface (21) to effect optical switching. When the input and reflection output devices are at a first position, an input light beam from the input device passes through the reflective surface of the prism, and is output through the transmission output device. When the input and reflection output devices are at a second position, the input light beam from the input device is incident on the reflective surface of the prism at an angle which is equal to or larger than a critical angle of the prism. The input light beam is totally reflected by the reflective surface of the prism and is output through the reflection output device.

Abstract: An operation unit of a PMD compensation module includes a PBS, a compensated part and a combiner. The PBS separates an optical input into a first polarized signal and a second polarized signal. The compensated part includes a fixed prism and a movable prism. The first polarized signal outputted from the PBS travels through the fixed prism and the movable prism in series. The light path of the first polarized signal in the movable prism is elongated or shortened according to a position of the movable prism. A continuously variable delay can thus be applied between the first and second polarized signals. The combiner recombines the first polarized signal received from the compensated part and the second polarized signal received from the PBS into an optical output signal.

Abstract: A high reflection isolation device includes a metal tube (1), a glass tube (2) enclosed by the metal tube, a dual fiber pigtail (DFP) (3) having a first fiber (30) and a second fiber (32), a GRIN lens (4) engaging with the metal tube via certain adhesive (7), a first filter (5) mounted on the GRIN lens and a second filter (6) mounted between the dual fiber pigtail and the GRIN lens. Light input from the first fiber passes through the GRIN lens and encounters the first filter. The first filter passes only a first wavelength of light and reflects all others, which pass back through the GRIN lens to the second filter. The second filter passes only a second wavelength of light, which is transmitted into the second fiber.

Abstract: An optical add-drop multiplexer successively comprises a first ferrule, a first graded index (GRIN) lens with a bandpass filter attached thereon, an optical crystal, a second GRIN lens, and a second ferrule. An input and an output optical fiber are stationed in the first ferrule, and a dropping and an adding optical fiber are stationed in the second ferrule. An optical multiplexed signal from the input optical fiber is transmitted through the first GRIN lens to the bandpass filter. From the bandpass filter, an optical signal having a wavelength identical to a central wavelength of the bandpass filter is output to the dropping optical fiber, and other optical signals having other wavelengths are coupled with an optical signal from the adding optical fiber having a wavelength identical to the central wavelength of the bandpass filter and are transmitted to the output optical fiber.