Nippon Telegraph and Telephone Corporation

Yuichiro Ikuma

Yusuke Nasu

Kenya Suzuki

Takashi Yamada

Manabu Oguma

Osamu Moriwaki

Takashi Go

Yuzo Ishii

Yuriko Kawamura

Tetsuo Takahashi

Ken Tsuzuki

Takashi Saida

Kiyofumi Kikuchi

Kei Kuwabara

Mitsumasa Nakajima

Takeshi Seki

Yuichi Higuchi

Shogo Yamanaka

Kazunori Seno

Naoki Ooba

Kotaro Takeda

Koichi Hadama

Makoto Jizodo

Takafumi Fukatani

An optical module is provided with a columnar protrusion over the entire pickup area (EP) for automatic suction by a mounting device at the center of the upper surface of a fiber holding carrier. The protrusion secures a dedicated pickup area (EP) on a top surface. When an extra length of an optical fiber extending from an optical device is routed and held between a pair of wall portions, the extra length including a tip portion is held in a storage area of the fiber holding carrier by a restoring force caused by being pressed against the wall portions.

Optical module

An optical circuit module in which an optical fiber array and an optical circuit substrate are connected, the optical fiber array including a groove substrate in which a groove for optical fiber alignment is formed, a pressing plate stacked on and bonded to the groove substrate, and an optical fiber bonded to and fixed in the groove of the groove substrate, and the optical circuit substrate including an input/output waveguide. In a connection surface of the optical circuit module, an area of a common portion in a cross section of the optical circuit substrate and the pressing plate is larger than an area of a common portion in a cross section of the optical circuit substrate and the groove substrate.

Optical circuit module

An optical fiber array includes a V-groove substrate in which a V-groove for optical fiber alignment is formed, a pressing plate laminated and bonded on the V-groove substrate, and an optical fiber bonded and fixed in the V-groove of the V-groove substrate, wherein a distance between the optical fiber and the V-groove is less than 20 μm.

Optical fiber connection structure

A wavelength monitoring apparatus includes a wavelength monitoring circuit. The wavelength monitoring circuit includes: a split circuit that splits an input optical signal into two; an optical delay circuit that applies a delay time difference to the two split optical signals; and a two-input two-output optical multiplexer/demultiplexer circuit that outputs a result of applying multiplexing interference to the optical signals to which the delay time difference has been applied. The wavelength monitoring apparatus further includes photoelectric conversion elements that perform photoelectric conversions on the two optical signals output from the wavelength monitoring circuit so as to output electrical signals. The wavelength monitoring apparatus is configured to obtain the wavelength of the optical signal, by calculating a ratio between two electrical outputs of the photoelectric conversion elements and referring to a correspondence table indicating wavelengths of optical signals input to the wavelength monitoring circuit and ratios between electrical outputs.

Wavelength monitoring device and controlling method thereof

An optical circuit of the present disclosure shares at least a part of an electrical path including phase variable means between neighboring optical interference circuits, or configures an electrical path so as to straddle neighboring optical interference circuits, thereby performing electrical or thermal feedback. The optical circuit includes a mechanism using the electrical or thermal feedback for cancelling components of thermal crosstalk from one optical interference circuit to another neighboring optical interference circuit. The optical circuit of the present disclosure has a resistor element that shares electrical paths including respective phase variable means between the neighboring optical interference circuits. The optical circuit changes the phase change amount by the phase variable means in the neighboring optical interference circuit, in such a way as to cancel the thermal crosstalk components by the resistor element.

Optical circuit with common ground configuration for resistors and thermo-optic phase shifters

There is provided an optical fiber array that can be easily optically connected to cores of optical waveguides on a connection counterpart substrate without requiring a complicated fabrication process to the connection counterpart substrate and laborious diffusing fusion of the cores. In an array, coating-removed exposed portions of fibers are attached to grooves that are provided on a lower substrate in order to position the optical fibers. Further, the exposed portions are pressed by a lid. Coated portions of the fibers are placed on a flat surface of a concave portion that is provided on the substrate to form a step with the grooves in a state where the exposed portions are attached. Front end parts of the exposed portions of the fibers each have a light collecting portion that collects light beams passing through an inside of the corresponding fiber to reduce an MFD. The light collecting portions are lens-shaped portions that are formed by cutting and are used for optical alignment with the cores of the optical waveguides.

Optical fiber array and connecting method thereof

An object is to improve crosstalk between ports while keeping an interposer circuit small. In an interposer circuit that includes a first surface connected to an optical circuit, a second surface that is connected to a fiber block and is located opposite to the first surface in parallel with the first surface, and a plurality of connection waveguides connected to a plurality of input/output waveguides included in the optical circuit and a plurality of input/output fibers included in the fiber block, the connection waveguides each have a straight shape, and an angle (θ) formed between the first surface and each of the connection waveguides is the same as an angle (φ) formed between the second surface and each of the connection waveguides.

Interposer circuit

To provide an optical 90-degree hybrid formed of a silicon waveguide capable of suppressing an optical loss and a phase error, and facilitating electronic packaging and optical packaging. In the optical 90-degree hybrid circuit including two optical branching units facing each other and two optical coupling units facing away from each other, four arm waveguides are arranged including bent waveguides each of which guides an output light of the optical branching unit to the optical coupling unit, and is formed in a curved shape.

Optical 90 degree hybrid circuit

A wavelength monitoring circuit obtains a light output proportional to only an input optical signal, independent of wavelength, by adding a light split circuit to the configuration in the related art, or changing the light split circuit to a light trifurcation circuit. In addition, wavelength monitoring with high accuracy is possible while improving the resistance to noise. The extraction of the light output proportional to only the input optical signal is performed by a light split circuit for input light at the top stage of the wavelength monitoring circuit or a light split circuit for interference in a stage in the middle of the circuit. The changed light split circuit causes the MZI included in the wavelength monitoring circuit to operate in a state of losing the balance of the configuration or the optical signal level, and increases the signal level near the bottom portion of the transmission characteristics.

Wavelength monitoring circuit

The invention provides a planar optical waveguide circuit capable of preventing part of the input signal light that has not been combined in the waveguide and propagates as leaked light from interfering with the output signal. A planar optical waveguide circuit having an optical waveguide embedded in a cladding layer includes: a plurality of parallel output optical waveguides configured to emit light from a same end face; a groove having a reflective interface formed at an angle of +45 degrees relative to the output optical waveguides and configured to reflect leaked light propagating in the cladding layer; and a groove having a reflective interface formed at an angle of &#x2212;45 degrees, the reflective interface formed at an angle of +45 degrees, the output optical waveguide, and the reflective interface formed at &#x2212;45 degrees being arranged repeatedly in that order.

Planar optical waveguide circuit

An incorrect insertion and removal prevention system that can prevent an operator from incorrectly selecting a port to be operated without sacrificing the port mounting density is described. An optical transmission deviceof the incorrect insertion and removal prevention system includes a plurality of portsfor transmitting and receiving an external signal, a touch sensorinstalled in each of the portsto detect a contact of the human body, a control unitfor causing a display unitto display information about the portcorresponding to the touch sensordetecting the contact of the human body, a storage unitfor storing information for distinguishing each port, and the display unitfor displaying the information for distinguishing each port

Insertion/removal error prevention system

Provided is a polarization multiplexing optical transmitting and receiving circuit that compensates for transmission side PDL so as to suppress a reduction in transmission power and makes a branching ratio of light from a light source variable between a transmission side and a receiving side according to a system to be used. The polarization multiplexing optical transmitting and receiving circuit includes an optical variable branching circuit that branches the light output from the light source, a light fixing symmetric branching circuit connected to one of outputs of the optical variable branching circuit and a light fixing asymmetric branching circuit connected to the other, optical receivers connected to two outputs of the light fixing symmetric branching circuit, respectively, optical transmitters connected to two outputs of the light fixing asymmetric branching circuit, a polarized wave rotator connected to one of the optical transmitters, and a polarized wave multiplexer that polarization-multiplexes the outputs of the optical transmitters.

Polarization multi/demultiplexed optical transceiver circuit

An optical signal processing device with a transponder aggregator function by which theoretical loss is not increased even if the number of necessary transponders is increased. Optical signals inputted from input ports are inputted to a PLC. The PLC has SBTs. The input ports are connected to the input-end SBT, and a plane wave is outputted from an output end of the PLC to the space side at an angle different for each input port. Optical signals outputted by the PLC are changed in their optical paths on the x-z plane by a cylindrical lens (Lsp) designed to refract optical signals in the x-axis direction, and are reflected by an LCOS at different regions corresponding to the positions of the input port. The reflected optical signals are incident on the output-end SBTs on the PLC, and are outputted to output ports via demultiplex parts.

Optical signal processing device

The invention provides a low-cost and easy-to-align optical signal processing device on which a plurality of WSS function units can be integrated using only a single lens. Optical signals input to the first input/output port group (-) are output into a space as collimated light via the microlens array (). The signal light propagating through the space will be wavelength-demultiplexed by the diffraction grating (), focused by the lens (), and focused at the upper part in the drawing, with respect to the y-axis direction of the spatial light modulator (). The light provided with a desired phase modulation and reflected by the spatial light modulator () is deflected at a desired angle in the y-z plane according to its phase setting, and further optically coupled to an arbitrary port by passing through the lens () again, thus the switching operation is completed.

Growing community of inventors

Atsugi, Japan

Yuichiro Ikuma