Kam Yin Lau

42876060, Sep 1, 1981

Sep 17, 1980

6/188160

Robert A. Administrator of the National Aeronautics and Space Frosch
George F. Lutes - Glendale CA
Kam Y. Lau - Pasadena CA

H04B 900

455617

A fiber optic transmission line stabilizer for providing a phase-stabilized signal at a receiving end of a fiber optic transmission line (26) with respect to a reference signal at a transmitting end of the fiber optic transmission line (26) so that the phase-stabilized signal will have a predetermined phase relationship with respect to the reference signal regardless of changes in the length or dispersion characteristics of the line (26). More particularly, a reference signal of RF frequency modulates a 0. 85 micrometer wavelength optical transmitter (20). The output of the optical transmitter (20) passes through a first optical filter (24) and a voltage-controller phase shifter (22), the output of the phase shifter (22) being provided to the fiber optic transmission line (26). At the receiving end of the fiber optic transmission line (26), the signal is demodulated, the demodulated signal being utilized to modulate a 1. 06 micrometer optical transmitter (34).

48436119, Jun 27, 1989

Aug 12, 1988

7/232505

Sze-Keung Kwong - Long Beach CA
Kam Y. Lau - Glendale CA
Nadav Bar-Chaim - Pasadena CA
Israel Ury - Los Angeles CA

Ortel Corporation - Alhambra CA

H01S 319

372 46

A buried heterostructure window device has an elongated layer of gain medium surrounded by a lower index of refraction medium for guiding light along the length of the gain medium. A window and an antireflective layer are deposited on the output end of the gain layer to minimize reflections. A portion of the gain medium nearer the output end of the device is electrically pumped, leaving an unpumped end of the gain medium remote from the output end. The unpumped portion of the gain medium absorbs light travelling along the length of the gain medium. This inhibits reflection from the end of the gain medium remote from the output end. When the device is pumped with a moderate power level, strong superluminescent output is obtained. When the device is pumped well above the lasing threshold by reason of "burning through" the unpumped absorbing portion of the gain medium, a single mode laser is obtained with side band power at least 20 db below the power of the principal oscillation mode. "Burning through" the unpumped absorbing portion can be inhibited by extracting current carriers from that portion of the medium.

47649348, Aug 16, 1988

Jul 27, 1987

7/078367

Sze-Keung Kwong - Long Beach CA
Kam Y. Lau - Glendale CA
Nadav Bar-Chaim - South Pasadena CA
Israel Ury - Los Angeles CA

Ortel Corporation - Alhambra CA

H01S 319

372 46

A buried heterostructure window device has an elongated layer of gain medium surrounded by a lower index of refraction medium of guiding light along the length of the gain medium. A window and an antireflective layer are deposited on the output end of the gain layer to minimize reflections. A portion of the gain medium nearer the output end of the device is electrically pumped, leaving an unpumped end of the gain medium remote from the output end. The unpumped portion of the gain medium absorbs light travelling along the length of the gain medium. This inhibits reflection from the end of the gain medium remote from the output end. When the device is pumped with a moderate power level, strong superluminescent output is obtained. When the device is pumped well above the lasing threshold by reason of "burning through" the unpumped absorbing portion of the gain medium, a single mode laser is obtained with side band power at least 20 db below the power of the principal oscillation mode. "Burning through" the unpumped absorbing portion can be inhibited by extracting current carriers from that portion of the medium.