Harmonic Lightwaves, Inc.

Joseph Kleefeld

Alan C Nilsson

Josef Berger

Chien-Yu Kuo

Doron Mick

Charles H Gall

Alfred Nicholson Riddle

Harry Chou

An optical transmission system enables launching at least 17 dBm of optical power at 1550 nm wavelength into an e.g. 50 km long span of standard telecommunications single-mode optical fiber, without incurring unacceptable penalties from stimulated Brillouin scattering, damage to optical phase modulators from excessive drive power or thermal effects, or signal degradations caused by the SBS suppression. High frequency modulation of the laser drive current is combined with lower frequency modulation of the phase of the laser output light that is itself varied over a range of approximately 25 MHz. This two tone modulation raises the SBS threshold to greater than 17 dBm in the 1550 nm wavelength region when the laser has a line width less than 10 MHz, under cw operation. By thereby dividing the task of spectral partitioning between the laser and the phase modulator, the RF input power level to the phase modulator is manageable and the laser operates in a regime that does not cause clipping.

Multi-tone phase modulation for light wave communication system

A laser-diode or laser diode array end-pumped solid-state laser package for optical communications and the like mounted on a common thermally conductive, low thermal expansion base that is temperature stabilized with a thermo-electric cooler. The laser package includes a heat sink, a thermo-electric cooler mounted on the heat sink, a base having a base plate portion mounted on the thermo-electric cooler and a block portion mounted on the base plate portion and optical elements mounted on the base plate and block. The laser active medium and collimating and focusing lenses are mounted with their optically axes collinear in a v-groove formed in a top surface of the block. A laser diode pump is mounted to the base plate and supported so that its laser emission is aligned with the length of the groove. One cavity mirror is a curved reflective coating on an end of the active medium which is transparent to the laser diode pump light and reflective of the active medium generated laser light, while a second cavity mirror is a planar mirror mounted on the base plate. The optical system is aligned at an operating temperature at which the laser diode light's wavelength matches an absorbption band of the active medium. A thermistor on the base plate measures the temperature so that a processor can adjust the electric current applied to the thermo-electric cooler to maintain the base plate temperature at the operating temperature even in extreme ambient temperatures.

Temperature stable solid-state laser package

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Palo Alto, CA, United States of America

Joseph Kleefeld