A single-ended output circulator includes a three-core optical fiber head having first, second, and third optical fiber cores; a walk-off crystal having a first surface facing towards the second end of the three-core optical fiber head tube and a second surface facing away from the second end of the three-core optical fiber head tube; a plurality of half-wave plates each having a first surface coupled to the second surface of the walk-off crystal and a second surface facing away from the second surface of the walk-off crystal; a collimating lens having a first end and a second end; a reflection mirror configured to reflect light beams from the collimating lens; an optical prism between the collimating lens and the reflection mirror and configured to transmit a light beam along a propagation direction according to a polarization direction of the light beam; and a polarization rotator.

In order to prevent a signal which a terminal station does not require from being intercepted by the terminal station without greatly changing the power of optical signals to be transmitted from a node to the terminal station, a node device is provided with: a first optical unit which outputs a first optical signal received from a first terminal station and addressed to a second terminal station, and a second optical signal received from the first terminal station, addressed to a third terminal station, and having a different wavelength band from the first optical signal; and a second optical unit to which the first and second optical signals outputted from the first optical unit are inputted, and which shifts the frequency of the first optical signal by a predetermined amount to create a fourth optical signal, passes the second optical signal without any change, couples the second and fourth optical signals, and transmits a resultant signal to the third terminal station.

Provided are a tunable wavelength filter with an embedded metal temperature sensor and an external-cavity type tunable wavelength laser module. In detail, the tunable wavelength filter with an embedded metal temperature sensor and the external-cavity type tunable wavelength laser module achieve wavelength stability by forming a metal temperature sensor using a resistance change of a metal thin film according to temperature on a point on an isothermal layer having the same temperature distribution as the optical waveguide during a process for fabricating the optical waveguide with polymer to accurately measure a temperature of an optical waveguide.

The present invention discloses an optical fiber filter with an ultra-wide tuning range, comprising an input optical fiber, a two-dimensional mechanical rotating mirror, a collimating and beam expanding system, two gratings, and an output optical fiber. The input optical fiber emits a multi-wavelength optical signal into the two-dimensional mechanical rotating mirror, the optical signal is reflected to the collimating and beam expanding system to form collimated beams, the collimated beams are incident on the gratings which generate dispersion to scatter different wavelengths to different angles, and lights of different diffraction angles are input into the output optical fiber by adjusting the two-dimensional mechanical rotating mirror. In the present invention, a two-dimensional mechanical rotating mirror is used to switch gratings of different wavebands, which can realize tuning of optical wavelengths in an ultra-wide range. The application scenarios are greatly expanded, the cost is reduced, and the optical path is simple, which can realize fast tuning. In addition, the number of channels is expanded by multiplexing the time and space of a rotating device.

Embodiment of present invention provide an optical subassembly that includes a first, a second, and a third band filter (BF) each having a common port (CP), a port-A (PA), and a port-B (PB). The PA of the second BF is connected to the PA of the third BF and the PB of the first BF is connected to the PB of the third BF. The optical subassembly is adapted to route a first optical signal of a blue band from the PA to the CP of the first BF; to route the first optical signal from the CP of the second BF to the CP of the third BF; to route a second optical signal of a red band from the CP of the third BF to the CP of the first BF; and to route the second optical signal from the CP to the PB of the second BF.

An optical fiber filter has an ultra-wide tuning range and includes a two-dimensional mechanical rotating mirror, a collimating and beam expanding system, and two grating. An input fiber emits a multi-wavelength optical signal into the rotating mirror, which reflects the signal to the system to form collimated beams. In turn, the collimated beams are incident on the gratings that disperse the light of different wavelengths to different angles. Lights of different diffraction angles are input into an output fiber by adjusting the rotating mirror. The rotating mirror can be used to switch between gratings of different wavebands to tune optical wavelengths in an ultra-wide range.

Embodiment of present invention provide an optical subassembly that includes a first, a second, and a third band filter (BF) each having a common port (CP), a port-A (PA), and a port-B (PB). The PA of the second BF is connected to the PA of the third BF and the PB of the first BF is connected to the PB of the third BF. The optical subassembly is adapted to route a first optical signal of a blue band from the PA to the CP of the first BF; to route the first optical signal from the CP of the second BF to the CP of the third BF; to route a second optical signal of a red band from the CP of the third BF to the CP of the first BF; and to route the second optical signal from the CP to the PB of the second BF.

A single-ended output circulator includes a three-core optical fiber head having first, second, and third optical fiber cores; a walk-off crystal having a first surface facing towards the second end of the three-core optical fiber head tube and a second surface facing away from the second end of the three-core optical fiber head tube; a plurality of half-wave plates each having a first surface coupled to the second surface of the walk-off crystal and a second surface facing away from the second surface of the walk-off crystal; a collimating lens having a first end and a second end; a reflection mirror configured to reflect light beams from the collimating lens; an optical prism between the collimating lens and the reflection mirror and configured to transmit a light beam along a propagation direction according to a polarization direction of the light beam; and a polarization rotator.

A densely-spaced wavelength division multiplexing (DWDM) transceiver utilizes a comb laser source to provide a multi-channel system capable of supporting at least twenty separate channels. The optical transmitter portion of the transceiver utilizes a double-pass (e.g., reflective) modulator configuration. The double-pass arrangement allows for a single grating (or other suitable dispersive element) to be used as a demultiplexer in combination with the comb laser source to separate the input optical beams into individual wavelength components, as well as a multiplexer for combining the plurality of separate modulated optical signals into a single, multi-channel DWDM optical output signal. The optical receiver portion of the transceiver includes a grating element to direct the multi-channel received optical signal into separate, wavelength-based channels, with the signal propagating along each channel directed into a separate photodiode.

A communication apparatus for a fiber-optic communication system for an aircraft that includes: an optical coupler; an input port optically coupled to the optical coupler via a first waveguide, the input port arranged to receive light; a modulator optically coupled to the optical coupler via a second waveguide, the modulator having a logic input and a fiber having a fiber Bragg grating (FBG) receiving light from the input port via the optical coupler, the modulator operable to vary a strain force applied to the fiber according to a logic signal received at the logic input to modulate a wavelength of a modulated light signal reflected by the FBG back to the optical coupler; and an output port optically coupled to the optical coupler via a third waveguide to receive the modulated light signal therefrom, the output port being operable to output the modulated light signal.