Semiconductor device manufacturing: process – Making device or circuit emissive of nonelectrical signal – Including integrally formed optical element
Reexamination Certificate
2002-05-01
2003-12-30
Pham, Long (Department: 2814)
Semiconductor device manufacturing: process
Making device or circuit emissive of nonelectrical signal
Including integrally formed optical element
C438S016000, C385S001000, C385S012000, C385S013000, C385S142000, C372S073000, C372S038060
Reexamination Certificate
active
06670210
ABSTRACT:
TECHNICAL FIELD
Semiconductor opto-electronic devices including semiconductor optical waveguides and methods of manufacture thereof are disclosed.
BACKGROUND OF THE RELATED ART
There is a wide-ranging demand for increased communications capabilities, including more channels and greater bandwidth per channel. The needs range from long distance applications such as telecommunications between two cities to extremely short range applications such as the data-communications between two functional blocks (fubs) in a semiconductor circuit with spacing on the order of a hundred microns.
Optical fibers can carry information encoded as optical pulses over long distances. The advantages of optical media include vastly increased data rates, lower transmission losses, lower basic cost of materials, smaller cable sizes, and almost complete immunity from stray electrical fields. Other applications for optical fibers include guiding light to awkward places (e.g., surgical applications), image guiding for remote viewing, and various sensing applications.
Optical fibers or waveguides provide an economical and higher bandwidth alternative to electrical conductors for communications. A typical optical fiber includes a silica core, a silica cladding, and a protective coating. The index of refraction of the core is higher than the index of refraction of the cladding to promote internal reflection of light propagating down the silica core.
Waveguides have been developed comprising a mixture of silica (SiO
2
) and silicon nitride (Si
3
N
4
), often referred to as SiON. The indexes of refraction of the core and cladding can be controlled by controlling the nitrogen content. That is, the nitrogen content of the core will be higher than that of the cladding to give the core a suitably higher index of refraction than the cladding.
However, the differences in the index of refraction of the core and cladding also result in birefringence, or the separation of the light pulse or ray into two unequally refracted pulses or rays. As a result, part of the light transmission is lost. For fiber optic communication systems where long range fiber optic communication is utilized, there is a need for optical and electro-optic devices that are substantially free from birefringence.
In general, birefringence is the difference between a refractive index n
TM
for the TM mode having a field component perpendicular to the substrate and a refractive index n
TE
for the TE mode having a field component parallel to the substrate, or, the birefringence equals n
TM
-n
TE
.
The majority of fiber optic telecommunications systems use standard single-mode silica fiber that does not preserve the polarization of the transmitted light. For such systems, the polarization state of the light signal in the optical fiber at any point and at any time is unknown and subject to variation over time and distance as a result of environmental and other changes that occur along the transmission path of the signal. If devices placed at any point in the fiber transmission path or at its end have response characteristics that depend on the polarization state of the light (i.e., polarization dependence), the signal may be degraded or lost altogether.
As integrated optical and electro-optical devices are employed in fiber optic systems for which the polarization state of the light signal is unknown, a need arises to circumvent or minimize the consequences of the polarization dependence and birefringence of these devices.
The most popular approach for reducing the effects of birefringence has been to introduce additional components to control the state of polarization of the light signal before its introduction to the polarization-sensitive device.
A more satisfactory approach would be to provide a waveguide device with a small polarization dependence and birefringence thereby causing only negligible transmission degradation.
REFERENCES:
patent: 4420873 (1983-12-01), Leonberger et al.
patent: 4518219 (1985-05-01), Leonberger et al.
patent: 5436991 (1995-07-01), Sunagawa et al.
patent: 5465860 (1995-11-01), Fujimoto et al.
patent: 5540346 (1996-07-01), Fujimoto et al.
patent: 5732179 (1998-03-01), Caneau et al.
patent: 5825047 (1998-10-01), Ajisawa et al.
patent: 5917980 (1999-06-01), Yoshimura et al.
patent: 5943465 (1999-08-01), Kawaguchi et al.
patent: 5961924 (1999-10-01), Reichert et al.
patent: 6075908 (2000-06-01), Paniccia et al.
patent: 6083843 (2000-07-01), Ohja et al.
patent: 6147366 (2000-11-01), Drottar et al.
patent: 6166846 (2000-12-01), Maloney
patent: 6178281 (2001-01-01), Sautter et al.
patent: 6195478 (2001-02-01), Fouquet
patent: 6215577 (2001-04-01), Koehl et al.
patent: 6268953 (2001-07-01), Maloney
patent: 6269199 (2001-07-01), Maloney
patent: 6304706 (2001-10-01), Sugita et al.
patent: 6501895 (2002-12-01), Bloechl et al.
patent: 2002/0132386 (2002-09-01), Bazylenko
Ayazi et al., “High aspect-ratio polysilicon micromachining technology,” Sensors and Actuators 87 (2000) 46-51.
Denisse et al., “Plasma-enhanced growth and composition of silicon oxynitride films,” J. Appl. Phys. 60 (7), Oct. 1, 1986, pp. 2536-2542.
Eldada et al., “Thermooptic Planar Polymer Bragg Grating OADM's with Broad Tuning Range,” IEEE Photonics Technology Letters, vol. 11, No. 4, Apr. 1999, pp. 448-450.
Fardad et al., “UV-light imprinted Bragg grating in sol-gel ridge glass waveguide with almost 100% reflectivity,” Electronics Letters, Jun. 5, 1997, vol. 33, No. 12. pp. 1069-1070.
Giles, “Lightwave Applications of Fiber Bragg Gratings,” Journal of Lightwave Technology, vol. 15, No. 8, Aug. 1997, pp. 1391-1403.
Goh et al., “High-Extinction Ratio and Low-Loss Silica-Based 8×8 Strictly Nonblocking Thermooptic Matrix Switch,” Journal of Lightwave Technology, vol. 17, No. 7, Jul. 1999, pp. 1192-1199.
Hibino et al., “Temperature-insensitive UV-induced Bragg gratings in silica-based planar lightwave circuits on Si,” Electronics Letters, Oct. 14, 1999, vol. 35, No. 21, pp. 1844-1845.
Itoh et al., “Low-Loss 1.5% &Dgr; Arrayed Waveguide Grating with Spot-Size Converters,” NTT Photonics Laboratories, 2 pages.
Kashyap et al., “Laser-Trimmed Four-Port Bandpass Filter Fabricated in Single-Mode Photosensitive Ge-Doped Planar Waveguide,” IEEE Photonics Technology Letters, vol. 5, No. 2, Feb. 1993, pp. 191-194.
Kitagawa et al., “Single-frequency Er3+-doped silica-based planar waveguide laser with integrated photo-imprinted Bragg reflectors,” Electronics Letters, Aug. 4, 1994, vol. 30, No. 16, pp. 1311-1312.
Kohnke et al, “Planar waveguide Mach-Zender bandpass filter fabricated with single exposure UV-induced gratings,” OFC '96 Technical Digest, p. 277.
Mahorowala et al., “In Situ Measurement of RIE Lag during Polysilicon Etching in a Lam TCP using Full Waver Interferometry,” http://www.plasma-processing.com/insitu.htm, 12 pages.
Maxwell et al., “UV Written 13 dB Reflection Filters in Hydrogenated Low Loss Planar Silica Waveguides,” Electronics Letters, Mar. 4, 1993, vol. 29, No. 5, pp. 425-426.
Miya et al., “Silica-Based Planar Lightwave Circuits: Passive and Thermally Active Devices,” IEEE Journal of Selected Topics in Quantum Elecrtronics, vol. 6, No. 1, Jan./Feb. 2000, pp. 38-45.
Moerman et al., “A Review on Fabrication Technologies for the Monolithic Integration of Tapers with III-V Semiconductor Devices,” IEEE Journal of Selected Topics in Quantum Electronics, vol. 3, No. 6, Dec. 1997, pp. 1308-1320.
Okamoto, “Bringing Telecom Networks up to Speed,” Circuits and Devices, Sep. 1998, pp. 26-34.
Singh et al., “Apodized Fiber Gratings for DWDM Using Variable Efficiency Phase Masks,” pp. 76-77.
Takahashi et al., “A 2.5 Gb/s, 4-Channel Multiwavelength Light Source composed of UV Written Waveguide Gratings and Laser Diodes Integrated on Si,” ECOC 97, Sep. 22-25, 1997, pp. 355-358.
Westerheim et al., “Substrate bias effects in high-aspect-ratio SiO2contact etching using an inductively coupled plasma reactor,” J. Vac. Sci. Technol. A 13(3), May/Jun. 1995, pp. 853-858.
White, “Integrated Components for Optical Add/Drop,” 29 pages.
Yonemura et al., “Session FT
Intel Corporation
Louie Wai-Sing
Marshall & Gerstein & Borun LLP
LandOfFree
Optical waveguide with layered core and methods of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical waveguide with layered core and methods of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical waveguide with layered core and methods of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3182411