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Semiconductor Reference Oscillator Development for Coherent Detection Optical Remote Sensing ApplicationsThe NASA Earth Science Enterprise Advanced Technology Initiatives Program is supporting a program for the development of semiconductor laser reference oscillators for application to coherent optical remote sensing from Earth orbit. Local oscillators provide the frequency reference required for active spaceborne optical remote sensing concepts that involve heterodyne (coherent) detection. Two recent examples of such schemes are Doppler wind lidar and tropospheric carbon dioxide measurement by laser absorption spectrometry, both of which are being proposed at a wavelength of 2.05 microns. Frequency-agile local oscillator technology is important to such applications because of the need to compensate for large platform-induced Doppler components that would otherwise interfere with data interpretation. Development of frequency-agile local oscillator approaches has heretofore utilized the same laser material as the transmitter laser (Tm,Ho:YLF in the case of the 2.05-micron wavelength mentioned above). However, a semiconductor laser-based frequency-agile local oscillator offers considerable scope for reduced mechanical complexity and improved frequency agility over equivalent crystal laser devices, while their potentially faster tuning capability suggest the potential for greater scanning versatility. The program we report on here is specifically tasked with the development of prototype novel architecture semiconductor lasers with the power, tunability, and spectral characteristics required for coherent Doppler lidar. The baseline approach for this work is the distributed feedback (DFB) laser, in which gratings are etched into the semiconductor waveguide structures along the entire length of the laser cavity. However, typical DFB lasers at the wavelength of interest have linewidths that exhibit unacceptable growth when driven at the high currents and powers that are required for the Doppler lidar application. Suppression of this behavior by means of corrugation pitch-modulation (using a detuned central section to prevent intensity peaking in the center of the cavity) is currently under investigation to achieve the required performance goals.
Document ID
20070034848
Acquisition Source
Jet Propulsion Laboratory
Document Type
Conference Paper
External Source(s)
Authors
Tratt, David M.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Mansour, Kamjou
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Menzies, Robert T.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Qiu, Yueming
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Forouhar, Siamak
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Maker, Paul D.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Muller, Richard E.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 24, 2013
Publication Date
August 28, 2001
Subject Category
Earth Resources And Remote Sensing
Meeting Information
Meeting: NASA Earth Science Technology Conference
Location: College Park, MD
Country: United States
Start Date: August 28, 2001
End Date: August 30, 2001
Distribution Limits
Public
Copyright
Other
Keywords
distributed feedback (DFB) laser
optical heterodyne detection
coherent laser remote sensing

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