A wavelength division multiplexer/demultiplexer, a photonic integrated chip, and an optical module are provided. The wavelength division multiplexer/demultiplexer includes a substrate, a bus waveguide provided on the substrate, and at least two wavelength division multiplexing/demultiplexing units provided on the bus waveguide. Each of the at least two wavelength division multiplexing/demultiplexing units includes a mode multiplexer and an asymmetric Bragg grating. The mode multiplexer includes a first port, a second port, and a third port. The third port is connected to the asymmetric Bragg grating, so as to input a light in a TE1 mode or a higher-order mode to the asymmetric Bragg grating. The asymmetric Bragg grating transmits light containing wavelengths other than a wavelength i. A grating period of the asymmetric Bragg grating and the wavelength i satisfy a resonance condition.

A wavelength division multiplexer/demultiplexer, a photonic integrated chip, and an optical module are provided. The wavelength division multiplexer/demultiplexer includes a substrate, a bus waveguide provided on the substrate, and at least two wavelength division multiplexing/demultiplexing units provided on the bus waveguide. Each of the at least two wavelength division multiplexing/demultiplexing units includes a mode multiplexer and an asymmetric Bragg grating. The mode multiplexer includes a first port, a second port, and a third port. The third port is connected to the asymmetric Bragg grating, so as to input a light in a TE1 mode or a higher-order mode to the asymmetric Bragg grating. The asymmetric Bragg grating transmits light containing wavelengths other than a wavelength i. A grating period of the asymmetric Bragg grating and the wavelength i satisfy a resonance condition.

Embodiments of present invention provide a digital dispersion compensation module. The digital dispersion compensation module includes a multi-port optical circulator; and a plurality of dispersion compensation units connected to the multi-port optical circulator, wherein at least one of the plurality of dispersion compensation units includes a fiber-bragg grating (FBG) having a first port and a second port; and an optical switch being capable of selectively connecting to one of the first port and the second port of the FBG, wherein the at least one of the plurality of dispersion compensation units is adapted to provide a positive dispersion to an optical signal, from the multi-port optical circulator, when the optical switch connects to the first port of the FBG and is adapted to provide a negative dispersion to the optical signal when the optical switch connects to the second port of the FBG.

Embodiments of present invention provide a digital dispersion compensation module. The digital dispersion compensation module includes a multi-port optical circulator; and a plurality of dispersion compensation units connected to the multi-port optical circulator, wherein at least one of the plurality of dispersion compensation units includes a fiber-bragg grating (FBG) having a first port and a second port; and an optical switch being capable of selectively connecting to one of the first port and the second port of the FBG, wherein the at least one of the plurality of dispersion compensation units is adapted to provide a positive dispersion to an optical signal, from the multi-port optical circulator, when the optical switch connects to the first port of the FBG and is adapted to provide a negative dispersion to the optical signal when the optical switch connects to the second port of the FBG.

Embodiments of present invention provide a digital dispersion compensation module. The digital dispersion compensation module includes a multi-port optical circulator; and a plurality of dispersion compensation units connected to the multi-port optical circulator, wherein at least one of the plurality of dispersion compensation units includes a fiber-bragg grating (FBG) having a first port and a second port; and an optical switch being capable of selectively connecting to one of the first port and the second port of the FBG, wherein the at least one of the plurality of dispersion compensation units is adapted to provide a positive dispersion to an optical signal, from the multi-port optical circulator, when the optical switch connects to the first port of the FBG and is adapted to provide a negative dispersion to the optical signal when the optical switch connects to the second port of the FBG.

Embodiments of present invention provide a digital dispersion compensation module. The digital dispersion compensation module includes a multi-port optical circulator; and a plurality of dispersion compensation units connected to the multi-port optical circulator, wherein at least one of the plurality of dispersion compensation units includes a fiber-bragg grating (FBG) having a first port and a second port; and an optical switch being capable of selectively connecting to one of the first port and the second port of the FBG, wherein the at least one of the plurality of dispersion compensation units is adapted to provide a positive dispersion to an optical signal, from the multi-port optical circulator, when the optical switch connects to the first port of the FBG and is adapted to provide a negative dispersion to the optical signal when the optical switch connects to the second port of the FBG.

Embodiments of present invention provide a digital dispersion compensation module. The digital dispersion compensation module includes a multi-port optical circulator; and a plurality of dispersion compensation units connected to the multi-port optical circulator, wherein at least one of the plurality of dispersion compensation units includes a fiber-bragg grating (FBG) having a first port and a second port; and an optical switch being capable of selectively connecting to one of the first port and the second port of the FBG, wherein the at least one of the plurality of dispersion compensation units is adapted to provide a positive dispersion to an optical signal, from the multi-port optical circulator, when the optical switch connects to the first port of the FBG and is adapted to provide a negative dispersion to the optical signal when the optical switch connects to the second port of the FBG.

Embodiments of present invention provide an optical signal transportation system. The system includes a first and a second optical line protection (OLP) node; a working signal transmission medium and a protection signal transmission medium between the first and second OLP nodes providing transportation paths for an optical signal from the first OLP node to the second OLP node; and at least one digital dispersion compensation module (DDCM) connected to at least one of the working and protection signal transmission media inside the second OLP node, wherein the DDCM includes a plurality of dispersion compensation units (DCUs) with each DCU being capable of providing either a positive or a negative dispersion selected by an optical switch to the optical signal, and wherein the DDCM is capable of providing the optical signal a total dispersion determined by the optical switch of each of the plurality of DCUs.

Embodiments of present invention provide an optical signal transportation system. The system includes a first and a second optical line protection (OLP) node; a working signal transmission medium and a protection signal transmission medium between the first and second OLP nodes providing transportation paths for an optical signal from the first OLP node to the second OLP node; and at least one digital dispersion compensation module (DDCM) connected to at least one of the working and protection signal transmission media inside the second OLP node, wherein the DDCM includes a plurality of dispersion compensation units (DCUs) with each DCU being capable of providing either a positive or a negative dispersion selected by an optical switch to the optical signal, and wherein the DDCM is capable of providing the optical signal a total dispersion determined by the optical switch of each of the plurality of DCUs.

Systems and methods for correcting chromatic dispersion in a remote distributed sensing application are disclosed. A remote distributed sensing system includes an interrogation subsystem configured to transmit an optical pulse and receive a reflection from the optical pulse. The remote distributed sensing system also includes a transit optical fiber coupled to the interrogation subsystem and having chromatic dispersion of a first slope at a frequency of the optical pulse, and an optical fiber under test being located in a remote location apart from the interrogation subsystem. The remote distributed sensing system additionally includes a chromatic dispersion compensator coupled in-line with at least one of the transit optical fiber and the optical fiber under test to adjust chromatic dispersion on the optical pulse in a direction of a second slope having an opposite sign from the first slope.