Optical: systems and elements – Deflection using a moving element – Using a periodically moving element
Reexamination Certificate
1999-02-11
2002-09-03
Chan, Jason (Department: 2633)
Optical: systems and elements
Deflection using a moving element
Using a periodically moving element
C359S199200, C359S199200, C385S007000, C385S008000, C385S009000, C385S014000, C385S015000, C385S027000, C385S028000, C372S006000, C372S032000, C372S064000
Reexamination Certificate
active
06445477
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to light sources for providing stable wavelength light for optical communication systems.
BACKGROUND OF THE INVENTION
Optical fiber communication systems are beginning to achieve their great potential for the rapid transmission of vast amounts of information. In essence, an optical fiber system comprises a light source, a modulator for impressing information on the light, an optical fiber transmission line for carrying the optical signals and a receiver for detecting the signals and demodulating the information they carry. The optical signals are typically within a wavelength range favorable for propagation within silica fibers and increasingly are wavelength division multiplexed (WDM) signals comprising a plurality of wavelength distinct wavelength channels within that range. Information is typically impressed upon the signal channels as by pulse code modulation.
Wavelength stability is important for the optical sources used in such systems. In contemplated systems, laser sources will be required to maintain their precise operating wavelengths over twenty years of field operation. It is doubtful that even the best current lasers can operate within the tight wavelength tolerances that projected wavelength channel spacings will require. Accordingly, there is a need for light sources with enhanced wavelength stability.
Mach-Zehnder waveguide interferometers for wavelength measurement have been proposed. See, for example, M. Teshima et al., “Multiwavelength simultaneous monitoring circuit employing wavelength crossover properties of arrayed waveguide grating”,
Electronics Letters,
31, pp. 1595-97 (1995). The difficulty with such devices, however, is that they are relatively inefficient, bulky, and not readily incorporated into a light source.
SUMMARY OF THE INVENTION
In accordance with the invention, a wavelength stable optical source comprises at least one adjustable wavelength optical source, a multipath Mach-Zehnder interferometer (MMZI) for receiving a signal from the adjustable source and providing a primary output and one or more secondary outputs, and a feedback arrangement responsive to the outputs for adjusting the wavelength source. Photodetectors coupled to the primary output and one or more of the secondary outputs provide feedback information for maintaining wavelength stability.
REFERENCES:
patent: 4842358 (1989-06-01), Hall
patent: 5428700 (1995-06-01), Hall
patent: 5862279 (1999-01-01), Amersfoort et al.
patent: 5920414 (1999-07-01), Miyachi et al.
patent: 6084992 (2000-07-01), Weber et al.
patent: 6222955 (2001-04-01), Lagali et al.
patent: 6292597 (2001-09-01), Lagali et al.
patent: 03253968 (1991-01-01), None
Teshima M. et al: “Multiwavelength Simultaneous Monitoring Circuit Employing Wavelength Crossover Properties Arrayed-Waveguide Grating”, Electronics Letters, GB, IEE Stevenage, vol. 31, Aug. 1995, pp. 1595-1597.
Madsen Christi Kay
Soole Julian Bernard
Lowenstein & Sandler PC
Lucent Technologies
Tran Dzung
LandOfFree
Self-monitored light source for stable wavelength optical... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Self-monitored light source for stable wavelength optical..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Self-monitored light source for stable wavelength optical... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2818365