Optical: systems and elements – Optical frequency converter – Dielectric optical waveguide type
Patent
1995-03-28
1997-09-30
Lee, John D.
Optical: systems and elements
Optical frequency converter
Dielectric optical waveguide type
385 15, 385122, G02F 135
Patent
active
056731400
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1 . Field of the Invention
The present invention relates to a non-linear semiconductor optical device. Such devices find application in optical communications systems, for instance as switches.
Embodiments of the present invention can show a relatively large and fast optical non-linearity and thus lend themselves to exploitation for instance in high speed or high data rate optical communication systems.
2. Related Art
Communications links which can carry high data rates are advantageous because they can transmit increased levels of information and/or can provide links via a single physical connection which services higher numbers of customers. For instance, time division multiplexed signals on a communications link can provide a higher number of time slots, and potentially therefore service a higher number of customers, where the link itself carries a higher data rate. Alternatively, ultra high bit rate links may enable customers to be offered large bandwidth services, and/or give telecommunications companies greater flexibility in managing their networks.
In order to access the data on a communications link, it is necessary to download the information on the link to a receiver. To do this, switching devices may be used, the speed of switching of the device being commensurate with the capability of the link for carrying high speed traffic. In optical communications, it is envisaged that data rates may be achieved as high as 100 Gbit/s or more, in the foreseeable future. This might be carried for instance in ten time slots, providing ten channels at 10 Gbit/s.
Data rates of 100 Gbit/s or higher will require all-optical switching elements since electronic components operating at such speeds are not available. Embodiments of the present invention can provide an important part of achieving ultra high bit rate links, providing a switching device potentially capable of demultiplexing for instance a 10 Gbit/s bit stream from a 100 Gbit/s optical time division multiplexed (0TDM) signal. An optical pump synchronised to the data stream might be used to switch out every tenth bit.
Applications of a large, fast optical non-linearity such as that provided by embodiments of the present invention go beyond just high data rate optical communication systems. In particular, there will be applications in all-optical processing and logic systems. A reference in this respect is a review paper: "Third Order Non-Linear Integrated Optics" by G. I. Stegeman et al., Journal of Lightwave Technology, vol 6 953-970 June 1988. This describes a range of devices and applications, many of which could be exploited using embodiments of the present invention.
A further desirable characteristic in an optical switching device is the combination of high speed of operation with moderate optical power requirements for switching, preferably the optical switching power being generated from a conventional source for optical transmission.
Recently, a large above-bandgap ultrafast optical non-linearity has been observed in active waveguides driven at the material transparency current. The above-bandgap non-linearity is reported in two papers, as follows: "Observations of Ultrafast Non-Linear Refraction in an InGaAsP Optical Amplifier", published in Applied Physic Letters volume 58 pages 1119-1121 (1991) by R. S. Grant and W. Sibbett, and "Ultrafast Refractive Index Dynamics in AlGaAs Diode Laser Amplifiers", published in Applied Physics Letters volume 59 page 635 (1991) by C. T. Hultgren and E. P. Ippen.
In an active waveguide as discussed herein, there is an optically confined active region of material which can be supplied in use with a drive current to produce gain by stimulated emission in optical radiation propagating through the active region. In the absence of electrical injection by means of the drive current, this active region leads to interband absorption of light for wavelengths shorter than the bandgap equivalent wavelength. The structure is designed such that current injection produces electron/hole populatio
REFERENCES:
patent: 4528464 (1985-07-01), Chemla et al.
patent: 5050183 (1991-09-01), Duling, III
patent: 5311525 (1994-05-01), Pantell et al.
patent: 5434700 (1995-07-01), Yoo
Fisher et al, "Ultrafast Nonlinear Refraction in an Active MQW Waveguide", Electronics Letters, vol. 29, No. 13, Jun. 1993, Stevenage GB, pp. 1185-1186.
Grant et al, "Observation of Ultrafast Nonlinear Refraction in an InGaAsP Optical Amplifier", Applied Physics Letters, vol. 58, No. 11, Mar. 1991, New York US, pp. 1119-1121.
Patent Abstracts of Japan, vol. 9, No. 259 (P-397) 17 Oct. 1985 & JP,A,60 108 818 (Matsushita) 14 Jun. 1985.
Cavailles et al, "Very Low Power Nonlinear Directional Coupling in a p-i(MQW)-n Vertical Coupler Using an Electrooptic Feedback", IEEE Photonics Technology Letters, vol. 2, No. 5, May 1990, New York US, pp. 343-345.
Patent Abstracts of Japan, vol. 16, No. 345 (P-1392) 27 Jul. 1992 & JP,A,04 104 130 (Hitachi) 6 Apr. 1992.
Elselt, "Optical Loop Mirror With Semiconductor Laser Amplifier", Electronics Letters, UK, vol. 28, No. 16, Jul. 1992, pp. 1505-1507 XP000309696.
Stegeman et al, "Third Order Non-Linear Integrated Optics", Journal of Lightwave Technology, vol. 6, Jun. 1988, pp. 953-970.
Hultgren et al, "Ultrafast Refractive Index Dynamics in AlGaAs Diode Laser Amplifiers", Applied Physics Letters, vol. 59, pp. 635-637, 1991 (Aug.).
Vu Van Lu'C et al, "Electrical Diagnostics of the Amplifier Operation and a Feasibility of Signal Registration the Basis of the Voltage Saturation Effect in Junction Laser Diodes", IEEE Journal of Quantum Electronics, QE19, pp. 1080-1083 (Jun.).
La Gasse et al, "Femto Second Measurements of the Non-Resonant Non-Linear Index in AlGaAs", Applied Physics Letters, vol. 56, pp. 417-419, 1990 (Jan.).
Mizahi et al, "Two Photon Absorption as a Limit to All-Optical Switching", Optics Letters, vol. 14, pp. 1140-1142, 1989 (Oct.).
Sheik-Bahae et al, "Dispersion of Bound Electronic Non-Linear Refraction in Solids", IEEE Journal of Quantum Electronics, vol. 27, pp. 1296-1309, 1991 (Jun.).
Tsang et al, "Two-Photon Absorption and Self-Phase Modulation in InGaAsP/InP Multi-Quantum-Well Waveguides", Journal of Applied Physics, vol. 70, pp. 3992-3994, 1991 (Oct.).
Davies et al, "Integrated Lossless 1 to 4 Optical/Combiner Operating at 1.55.mu.m", Post Deadline Paper (PD10) at Topical Meeting on Optical Amplifiers and Applications, Santa Fe, New Mexico, Jun. 24-26, 1992.
Cooper et al, "High-Power 1.5.mu.m All-Movpe Buried Heterostructure Graded Index Separate Confinement Multiple Quantum Well Lasers", Electronics Letters, vol. 25, pp. 1635-1636, 1989 (Nov.).
Seltzer et al, "Zero-Net-Strain and Conventionally Strained InGaAsP/InP Multiquantum Well Lasers", Electronics Letters, vol. 28, pp. 63-65, 1992 (Jan.).
O'Neill et al, "All-Optical Loop Mirror Switch Employgin an Asymmetric Amplifier/Attenuation Combination", Electronics Letters, 1990, vol. 26, pp. 2008-2009 (Nov. 1990).
Smith et al, "All-Optical Clock Recovery Using a Mode-Locked Laser", Electronics Letters, vol. 28, No. 19, pp. 1814-1816, 1992 (Sep.).
British Telecommunications public limited company
Lee John D.
LandOfFree
Non-linear semiconductor optical device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Non-linear semiconductor optical device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Non-linear semiconductor optical device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2261064