National Institute of Advanced Industrial Science and Technology

Sumitomo Electric Industries, Limited

Fujitsu Corporation

Ken Tanizawa

Shu Namiki

Hiroyuki Matsuura

Haruhiko Kuwatsuka

Katsumi Uesaka

Kazuhiro Ikeda

Eiichi Banno

Hitoshi Kawashima

Hajime Shoji

Keijiro Suzuki

Suguru Akiyama

Takeshi Matsumoto

Satoshi Suda

Guangwei Cong

An optical amplifier includes a polarization splitter, a polarization rotator, first and second optical couplers, and first and second semiconductor optical amplifying devices. The TE polarized wave of light split by the polarization splitter is input to a first input port of the first optical coupler. The TM polarized wave of the split light is converted into a TE polarized wave by the polarization rotator to be input to a second input port of the first optical coupler. First light and second light output from a first output port and a second output port of the first optical coupler are amplified by the first semiconductor optical amplifying device and the second semiconductor optical amplifying device to be input to a first input port and a second input port of the second optical coupler, respectively. Third light is output from an output port of the second optical coupler.

Optical amplifier and optical switch device

Provided is a driving device for PWM control of voltage pulses for controlling the temperature of a heater in a phase controller, the driving device being capable of increasing the response speed of an optical element such as an optical switch. Phase controllers include first and second heaters for changing the temperatures of first and second optical waveguides extending in parallel. Driving devices include pulse generation circuits that generate voltage pulses to apply to the first and second heaters. To start raising the temperature of the second heater, the pulse generation circuit generates a first voltage pulse and consecutive second voltage pulses to apply to the second heater with zero voltage pulse being applied to the first heater, the first voltage pulse having a long pulse width and the second voltage pulses following the first voltage pulse and having a shorter pulse width than the first voltage pulse.

Driving device and driving method for phase controller, and optical switch

A laser apparatus for tuning the emission wavelength of a wavelength tunable laser diode will be described. The apparatus includes a tunable LD with heaters to tune the emission wavelength of the tunable LD, and a controller to control the power supplied to the heaters. A feature of the laser apparatus is that the controller supplies pre-emphasis power to the heaters before the supplement of the power corresponding to the re-tuned emission wavelength to accelerate the stability of the temperature of the heaters.

Laser apparatus and method to re-tune emission wavelength tunable LD

A system includes: a splitter to branch an optical signal output by a wavelength-tunable light source into first to third optical signals; a first photodiode to perform an optical electrical conversion of the first optical signal transmitting a first etalon; a second photodiode to perform an optical electrical conversion of the second optical signal transmitting a second etalon, an FSR of the second etalon being identical to that of the first etalon, peak wavelengths of intensity of a transmitted light of the second etalon being different from those of the first etalon; a third photodiode to perform an optical electrical conversion of the third optical signal; and a controller to control the wavelength-tunable light source with use of a coefficient calculated by following formulas (1) or (2), Coefficient=(PD1&#x2212;A&#xb7;PD3)/(PD2&#x2212;B&#xb7;PD3) (1) and Coefficient=(PD2&#x2212;B&#xb7;PD3)/(PD1&#x2212;A&#xb7;PD3) (2).

System to control wavelength and method to control wavelength

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Tsukuba, Japan

Ken Tanizawa