초록 ▼

A tunable laser includes a laser medium (24), a resonant cavity (27, 28), at least one Faraday rotation element (26), and a polarization sensitive attenuator (25). Waves of laser energy produced by the laser medium resonate in the resonant cavity between a 100% reflective surface (27) and a partiall

A tunable laser includes a laser medium (24), a resonant cavity (27, 28), at least one Faraday rotation element (26), and a polarization sensitive attenuator (25). Waves of laser energy produced by the laser medium resonate in the resonant cavity between a 100% reflective surface (27) and a partially transmitting mirror surface (28). The waves pass through the attenuator (25) and are linearly polarized. The linearly polarized waves pass through the Faraday rotation element (26) and the polarization sensitive attenuator (25) on each pass through the resonant cavity. The Faraday rotation element includes a permanent magnet (54) and a trim coil (56) for generating both fixed and variable components of a magnetic field. The polarized wave is rotated by an amount proportional to the intensity of the total magnetic field and the wavelength of the polarized wave. The polarization sensitive attenuator allows only waves of a prescribed polarization angle to pass therethrough without attenuation. Only unattenuated waves continue to resonate within the resonant cavity. In one embodiment, the Faraday rotation element and the laser medium are combined in a single element. The laser is tuned by varying the current applied to the trim coil, thereby adjusting the amount of rotation imparted to the polarized wave, which amount of rotation determines the particular wavelength that is allowed to resonate within the resonant cavity without attenuation.

대표청구항 ▼

A tunable laser comprising: a laser medium, including means for exciting said laser medium with sufficient energy to produce a broad band of laser energy; means for linearly polarizing said wave of laser energy; a resonant cavity wherein said wave of polarized laser energy resonates between specifie

A tunable laser comprising: a laser medium, including means for exciting said laser medium with sufficient energy to produce a broad band of laser energy; means for linearly polarizing said wave of laser energy; a resonant cavity wherein said wave of polarized laser energy resonates between specified points; at least one adjustable Faraday rotation device withins aid resonant cavity, said Faraday rotation device having a magneto optically active material aligned to have said resonating wave of polarized laser energy pass therethrough, said rotation device further having means for generating a magnetic field having an adjustable intensity, said magnetic field causing the angle of polarization of the polarized wave passing therethrough to be rotated by an amount proportional to the wavelength of the laser energy and the intensity of the magnetic field; and a polarization sensitive attenuator within said resonant cavity, said attenuator allowing only linearly polarized waves of a prescribed polarization angle to pass therethrough without attenuation; the wavelength of the resonating wave of polarized laser energy that continues to resonate within said resonant cavity without attenuation being tunable to a desired wavelength by selectively adjusting the intensity of the magnetic field within said rotating device.