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US 6,700,910 B1Granted
Wavelength tunable laser and optical device
AssigneeHitachi, Ltd.
InventorsMasahiro Aoki, Shinya Sasaki, Tomonobu Tsuchiya, Hiroyuki Gomyo
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AssigneeHitachi, Ltd.
InventorsMasahiro Aoki, Shinya Sasaki, Tomonobu Tsuchiya, Hiroyuki Gomyo
Estimating the term…
In order to form a wavelength tunable laser capable of tuning a wave over a wide range by simple control means, a thin film heater is mounted either over an upper electrode of a ridge waveguide semiconductor laser having ridge waveguides on a semiconductor substrate or over the semiconductor substrate and on both sides of the ridge waveguide with a gap of a few μm. By controlling a current passed to the thin film heater, the oscillation wavelength of the semiconductor laser is tuned. In the case where the thin film heater is mounted over an upper electrode of a ridge waveguide, a nonconductor is formed on both sides of the ridge conductor to more efficiently enable heat from the heater to reach an active layer of the ridge waveguide more efficiently.
A wavelength tunable laser comprising:
A wavelength tunable laser comprising:
A wavelength-division multiplexing transmission system for transmitting light signals of different wavelengths of a plurality of channels through the same optical transmission line, comprising a plurality of first light sources for the plurality of channels, a spare light source for the first light sources, a Mach-Zehnder type optical modulating unit for modulating output light of the spare light source,
Dependencies are inferred from the claim text.