Abstract: A polarization converter based on taking a high-order TE mode as a transition mode comprises a ridge waveguide (1) and a slab waveguide (2) that are arranged in double layers and varying in width, and a strip waveguide (4) which is varying in width. The ridge waveguide (1) is disposed on the upper end face of the slab waveguide (2), and is aligned with two ends of the slab waveguide (2). The right end of the ridge waveguide (1) and the slab waveguide (2) are connected with the strip waveguide (4) with the varying width. A TM0 mode enters from the left ends of the ridge waveguide and the slab waveguide, and is converted into a TE0 mode for output. On the contrary, the TE0 mode enters from the right end of the strip waveguide and is converted into the TM0 mode for output.

Abstract: An on-chip mode converter-based silicon-germanium photoelectric detection apparatus comprises an insulating substrate, an optical coupler, an on-chip mode converter and a multi-mode silicon-germanium photoelectric detector. The optical coupler, the converter and the photoelectric detector are sequentially connected and all fixed on silicon wafers of the insulating substrate. An incident fundamental mode optical signal is transmitted to the optical coupler through a single-mode fiber, enters the converter via the optical coupled. The converter converts the fundamental mode optical signal into a multi-mode optical field and enters the photoelectric detector, which converts the multi-mode optical field into an electrical signal. Heavily germanium-doped region are located in areas with relatively weak distributed light intensity of the multi-mode optical field.

Abstract: A broadband polarization beam splitter/combiner based on a gradient waveguide directional coupler, comprises a gradient waveguide directional coupler, a beam combining end (1), a curved waveguide (5), a TE mode end (6) and a TM mode end (7). The coupler consists of a straight end gradient waveguide (2) and a serial end gradient waveguide (3). The trend of change of the gradient waveguide (2) is opposite to the gradient waveguide (3), and a gap is provided between the gradient waveguide (2) and the gradient waveguide (3). The beam combining end (1) is connected with one end of the gradient waveguide (2), the other end of the gradient waveguide (2) is connected with one end of the curved waveguide (5), the other end of the curved waveguide (5) is connected with the TE end (6), and the waveguide (3) is connected with the TM end (7).

Abstract: The present invention discloses a GSG track-type radio-frequency electrode, a silicon-based traveling-wave electrode light modulator, and a preparation method, and relates to the field of high-speed electro-optical chips. The GSG track-type radio-frequency electrode includes a GSG-type planar electrode, where a track electrode used for delaying an electric field is periodically added to one side or dual sides of the GSG-type planar electrode, and the track electrode is connected to a ground electrode of the GSG-type planar electrode. The silicon-based traveling-wave electrode light modulator includes the GSG track-type radio-frequency electrode and a conventional silicon-based traveling-wave electrode light modulator, and the GSG track-type radio-frequency electrode is connected to an active region of the silicon-based traveling-wave electrode light modulator by using through holes between electrode layers.

Abstract: A low-loss few-mode fiber relates to the technical field of optical communications and related sensing devices, and includes, from inside to outside, a core layer (1), a fluorine-doped quartz inner cladding (2), a fluorine-doped quartz second core layer (3), a fluorine-doped quartz depressed cladding (4) and a fluorine-doped quartz outer cladding (5); germanium element is not doped within the core layer (1), the refractive index of the core layer (1) is in gradient distribution, and the distribution is a power-exponent distribution; the maximum value of difference in relative refractive index between the core layer (1) and the fluorine-doped quartz inner cladding (2) is 0.3% to 0.9%; the relative refractive index difference of the fluorine-doped quartz inner cladding (2) with respect to synthetic quartz is ?0.3% to ?0.5%; the difference in relative refractive index between the fluorine-doped quartz second core layer (3) and the fluorine-doped quartz inner cladding (2) is 0.05% to 0.

Abstract: The present disclosure relates to a dual-channel orthogonal carriers assisted optical signal transmitting device, and a direct detection method and a direct detection system using the dual-channel orthogonal carriers assisted optical signal. The direct detection system using the dual-channel orthogonal carriers assisted optical signal comprises a transmitting device and a receiving device. The transmitting device is configured to generate and transmit a dual-channel orthogonal carriers assisted optical signal to be detected, wherein the dual-channel orthogonal carriers assisted optical signal is modulated with a modulation signal. The receiving device is configured to receive the dual-channel orthogonal carriers assisted optical signal, and recover amplitude and phase information of the modulation signal based on the dual-channel orthogonal carriers assisted optical signal.

Abstract: There are provided a wavelength selective switch device, a communication apparatus and a wavelength switching method. The wavelength selective switch device includes an incidence unit; an exit unit; a wavelength diversifying-synthesizing unit for diversifying and multiplexing the respective incident lights in a first axis direction; a light adjustment unit for making the lights of respective wavelengths be not diversified in the second axis direction; a liquid crystal beam deflection unit having a plurality of pixels divided into sub-regions, for deflecting the lights of the respective wavelengths by changing phase-shift characteristics of the pixels in the sub-regions; a reflection unit, disposed in parallel with the liquid crystal beam deflection unit; a deflection driving unit for driving electrodes of the pixels to generate required phase-shift characteristics.

Abstract: A wavelength selective switch and a wavelength selection method are provided. The wavelength selective switch comprises a plurality of input ports, via which a plurality of light beams are input respectively, each light beam including at least one optical signal of a predetermined wavelength; at least one output port; and a wavelength separation apparatus including a wavelength separation device and a micro-mirror group, the wavelength separation device being configured to separate at least one optical signal from a light beam input via a predetermined one of the plurality of input ports, and the micro-mirror group being configured to adjust a propagation direction of the at least one optical signal, so that the at least one optical signal is output via a predetermined one of the at least one output port.

Abstract: A wavelength selective switch and a wavelength selection method are provided. The wavelength selective switch comprises an input port, through which a light beam, including a plurality of optical signals having different wavelengths, is incident; a wavelength separation apparatus, including a Blue Phase Liquid Crystal (BPLC) device and configured to separate at least one optical signal from the light beam through the BPLC device; and at least one output port, configured to output the at least one optical signal separated by the wavelength separation apparatus respectively. With the wavelength selective switch and the wavelength selection method, a polarization-independent phase modulation can be realized without a depolarization device disposed in an optical path, which thereby simplifies an optical path, reduces an insertion loss, and lowers costs of the wavelength selective switch and even the entire optical communication system.

Abstract: A transmitting system, a receiving system, a transmitting method and a receiving method capable of implementing communications with multiple rates are described.

Abstract: The present disclosure relates to a dual-channel orthogonal carriers assisted optical signal transmitting device, and a direct detection method and a direct detection system using the dual-channel orthogonal carriers assisted optical signal. The direct detection system using the dual-channel orthogonal carriers assisted optical signal comprises a transmitting device and a receiving device. The transmitting device is configured to generate and transmit a dual-channel orthogonal carriers assisted optical signal to be detected, wherein the dual-channel orthogonal carriers assisted optical signal is modulated with a modulation signal. The receiving device is configured to receive the dual-channel orthogonal carriers assisted optical signal, and recover amplitude and phase information of the modulation signal based on the dual-channel orthogonal carriers assisted optical signal.

Abstract: A transmitting device, a receiving device, an optical communication system, and associated methods are provided. The transmitting device transmits an optical signal containing data, and comprises: an optical tone generator for generating at least one optical tone; at least one encoder for performing advanced coding on at least one data signal respectively, each of the at least one data signal carrying a part of the data; at least one mapper for performing high order modulation on the at least one coded data signal; and an up-converter for up-converting the at least one high-order-modulated data signal into the optical signal to be outputted through the at least optical tone. Thereby, high speed (e.g., over 1-Tb/s) transmission per single channel over a long-haul distance (e.g. over 1000-km) with error-free recovery may be achieved.

Abstract: An optical communication system, a transmission apparatus and a reception apparatus, and a transmission method and a reception method are provided. The transmission apparatus transmits an optical signal, and comprises: at least one encoder for encoding at least one data signal, respectively; at least one first modulator for performing first modulation on the at least one encoded data signal, respectively, and generating at least one first modulated signal; at least one second modulator for performing second modulation, which is DFT-spread-OFDM modulation, on the at least one first modulated signal, respectively, and generating at least one second modulated signal; and an up-converter for up-converting the at least one second modulated signal into the optical signal to be transmitted. Thus, a PAPR of the optical OFDM transmission signal is decreased, a signal distortion caused by non-linearity of optical devices is reduced, and a reception quality of the signal is improved.

Abstract: There are provided a wavelength selective switch device, a communication apparatus and a wavelength switching method. The wavelength selective switch device includes an incidence unit; an exit unit; a wavelength diversifying-synthesizing unit for diversifying and multiplexing the respective incident lights in a first axis direction; a light adjustment unit for making the lights of respective wavelengths be not diversified in the second axis direction; a liquid crystal beam deflection unit having a plurality of pixels divided into sub-regions, for deflecting the lights of the respective wavelengths by changing phase-shift characteristics of the pixels in the sub-regions; a reflection unit, disposed in parallel with the liquid crystal beam deflection unit; a deflection driving unit for driving electrodes of the pixels to generate required phase-shift characteristics.

Abstract: A bias voltage control system and method for an optical IQ modulator are disclosed. The optical IQ modulator includes an I-branch Mach-Zehnder Modulator (MZM) to which an I-branch bias voltage is applied, a Q-branch MZM to which a Q-branch bias voltage is applied, and an optical phase shifter to which an orthogonal bias voltage is applied. The system comprises a photo-detector converting at least a part of an optical signal output by the optical IQ modulator to an electrical signal; an analog-to-digital converter converting the electrical signal to a digital signal; and a digital signal processor superimposing a first dither signal and a second dither signal on the I-branch bias voltage and the Q-branch bias voltage respectively to generate a first order harmonic signal and a second order harmonic signal, and controlling the bias voltages according to powers of a DC component, and the first and second order harmonic signals.

Abstract: A reconfigurable optical add/drop multiplexer and a reconfigurable optical add/drop multiplexing method are provided. The reconfigurable optical add/drop multiplexer comprises: an optical processing unit for receiving a first optical signal containing a plurality of optical channels, processing the first optical signal to generate a second optical signal which is a part of the first optical signal, and outputting the second optical signal; and a coherent detection unit for performing a coherent detection on the second optical signal so as to separate from the second optical signal an optical channel contained therein, and outputting the optical channel.

Abstract: A modulation device and method, and a demodulation device and method are provided. The modulation device modulates plural baseband signals to generate an optical signal, and comprises: plural modulation units for modulating plural electrical carriers with different frequencies by using the baseband signals respectively, to generate corresponding electrical modulated signals; a synthesizer for synthesizing the electrical modulated signals to generate a single electrical synthesized signal; an optical modulation unit for modulating a single optical carrier by using the electrical synthesized signal to generate the optical signal, wherein signal components corresponding to the baseband signals in the optical signal are distributed on both sides of a carrier frequency of the optical carrier at a predetermined frequency interval.

Abstract: A bias voltage control system and method for an optical IQ modulator are disclosed. The optical IQ modulator includes an I-branch Mach-Zehnder Modulator (MZM) to which an I-branch bias voltage is applied, a Q-branch MZM to which a Q-branch bias voltage is applied, and an optical phase shifter to which an orthogonal bias voltage is applied. The system comprises a photo-detector converting at least a part of an optical signal output by the optical IQ modulator to an electrical signal; an analog-to-digital converter converting the electrical signal to a digital signal; and a digital signal processor superimposing a first dither signal and a second dither signal on the I-branch bias voltage and the Q-branch bias voltage respectively to generate a first order harmonic signal and a second order harmonic signal, and controlling the bias voltages according to powers of a DC component, and the first and second order harmonic signals.

Abstract: A system and method for generating an optical comb are provided. The system comprises at least one modulator for modulating a continuous wave sequentially by using at least one signal, respectively so as to generate a comb wave having a first plurality of subcarriers; and a nonlinear medium for causing the respective subcarriers of the comb wave to perform four-wave mixing to thereby generate a comb wave having a second plurality of subcarriers as the optical comb. With the present system and method, an ultra-wide spectrum optical comb with stable frequencies may be generated.

Abstract: A deep packet inspection and control device for performing real-time traffic management on a real-time packet data stream over the internet that includes a first rule table unit for storing a rule table including a first set of rule entries which are pre-defined or generated dynamically; a first scanning unit for receiving a first real-time packet data stream from the internet, and scanning the first real-time packet data stream according to a scanning window defined by the first set of rule entries; a first analysis unit for matching the first real-time packet data stream with the first set of rule entries in the scanning window of the first scanning unit, and outputting a matching result; and a first rule linkage unit for performing linkage control on the first real-time packet data stream to be output back to the internet according to the matching result output from the first analysis unit.