Nippon Telegraph and Telephone Corporation

Naoto Yoshimoto

Takeshi Sakamoto

Katsumi Iwatsuki

Shingo Kawai

Takashi Mitsui

Youichi Fukada

Kenichi Suzuki

Toshio Watanabe

Hiroshi Takahashi

Kiyoshi Matsumoto

Masamichi Fujiwara

Hiromasa Tanobe

Manabu Oguma

Tsutomu Kitoh

Yasutaka Kimura

Hideo Kawata

Hideo Kawada

Toru Ogawa

The present invention relates to an optical coupling/splitting device that realizes the splitting of a down-signal and the coupling of up-signals by the same optical device, and reduces coupling losses of the up-signal. An optical coupling/splitting device in the present invention comprises an optical coupling/splitting means for coupling a plurality of up-signals in a multi-mode for output and splitting a down-signal in a single mode for output, and a two-way optical propagation means for propagating the up-signal that is output from the optical coupling/splitting means in a multi-mode for output and propagate the down-signal in a single mode to be output to the optical coupling/splitting means.

Optical coupling/splitting device, two-way optical propagation device, and optical-transmit-receive system

A self-diagnostic method for PON protection system, in which optical switch-related failure can be previously inspected, and a PON protection system. A circuit is configured while an optical switch is switched so that signal light from an ONU is input to both a normal system OSU and a redundancy system OSU of an optical access network including the ONU, and there are conducted a circuit configuration test in which the signal light to the normal system OSU and the signal light to the redundancy system OSU are monitored for a predetermined period of time, and when the signal light to one of the OSUs and the signal light to the other do not correspond to each other, it is judged as abnormality and an open state test in which an optical switch is opened so that the signal light from the ONU is input to only the normal system OSU of the optical access network including the ONU, a circuit of the redundancy system OSU and the ONU is brought into an open state, the signal light to redundancy system OSU is monitored for a predetermined time of period, and when the signal light to the redundancy system exists, it is judged as abnormality.

Self-diagnostic method for PON protection system, and PON protection system

A normal system OSU, a redundancy system OSU, an optical switch, a concentration switch, and a controller which detects a command input by operation control and performs control according to the command are provided, and in such a state that the controller detects a redundancy system switching command indicating that the normal system OSU is switched to the redundancy system OSU, the controller induces the concentration switch to change a storage destination of a down signal, instructs the normal system OSU which is the switching source OSU to stop transmission of a transmission permission message, instructs the optical switch to switch a path after receiving remaining data processing completion notifications from the concentration switch and the normal system OSU which is the switching source OSU, writes accumulated information about the normal system OSU, which is the switching source OSU, in the redundancy system OSU, and notifies the concentration switch of completion of switching, whereby a down signal is transmitted from the concentration switch.

Optical network system

In the present invention, the extremely complicated setting and control and an extremely expensive optical component (wavelength locker) are not required, and optical output wavelength and optical output power can simply be set and controlled at a moderate price. At least one value for determining a dependence of the optical output wavelength on drive current and device temperature and at least one value for determining a dependence of the optical output power on drive current and device temperature in a light emitting device constituting first meansfor emitting light are stored in fourth means. Fifth meansdetermines drive current or optical output power c and device temperature d, at which both the optical output wavelength and optical output power of the light emitting device are separately specified value b, from a relationship among the drive current, device temperature, and optical output wavelength of the light emitting device, the relationship being determined by the at least one value, and a relationship among the drive current, device temperature, and optical output power, the relationship being determined by the at least one value, and the fifth meansgives the drive current or optical output power c and device temperature d as target values to second meansand third means

Optical communication light source unit and wavelength monitoring control method

The present invention provides wavelength monitoring and/or control enabling size reduction and low power operation without requiring a complicated optical system in its wavelength monitoring and controlling mechanism. The measurement portion () measures temperature by a thermistor () in the measurement portion, and measures a bias current by using an LD drive current detecting circuit (). The LD temperature, optical output and bias current are measured by the measurement portion. The relationship between the LD temperature and wavelengths or between the temperature, bias current and wavelengths is stored in a memory map of the storage portion (). The central controlling portion () calculates wavelengths on the basis of the temperature and the bias current or the temperature information of the measurement portion, and the relationship between the LD temperature, bias current and wavelengths or between the temperature and wavelengths of the storage portion.

Optical module and method for monitoring and controlling wavelengths

Growing community of inventors

Yokosuka, Japan

Naoto Yoshimoto