Κατασκευή-ανάπτυξη µικροδοµών Ανάπτυξη ολοκληρωµένων οπτικών Μικροεναπόθεση, µικροχάραξη, Rapid prototyping Κατεργασία υλικών µε Laser
ΑΝΑΠΤΥΞΗ ΚΥΜΑΤΟ ΗΓΩΝ «Μικροοπτικές διατάξεις-ολοκληρωµένα οπτικά»
Patterning process of glass waveguides
Κατασκευή οπτικής ίνας ALCATEL
Fiber drawing ALCATEL
Wavelength Division Multiplexing It is possible to send several different wavelenghts in parallel through one fiber-just think of several different colors. A 1.5 µm SiO2/GeO2 monomode fiber will carry optical signals in the wavelength range from 1.525 to 1.610 µm.presently only the center segment of this bandwidth is used: Center band (C-band): 1538-1570 nm Total available bandwidth: 4 THz= 4000 GHz Carrier frequency spacing: 50 GHz (=0.4 nm) at 80 channels. Expected total bitrate for 80 channels (C-band): 80x10 GBit/sec=0.8 TBit/s fiber array block
WDM: dispersive element Surface Acoustic Wave component (expensive) Gratings (not to all geometries, expensive) Phased Array Devices Demultiplexer DEMUX
ΚΥΜΑΤΟ ΗΓΟΙ LiNbO 3 1. Μεθοδοι κατασκευής κυµατοδηγών LiNbO 3 Επιταξιακή ανάπτυξη: µονοκρύσταλλος LiNbO 3 αναπτύσσεται επιταξιακά πάνω σε LiΤαO 3 µε την ιδια κρυσταλλική δοµή Sputtering: µονοκρύσταλλος LiNbO 3 εναποτίθεται σε γυαλί όπως corning 7059 Εξω-διάχυση: θερµαίνοντας το LiNbO 3 σε κενό στους 1000 ο C, Li2O ελευθερώνεται από την επιφάνεια του κρυστάλλου, δίνοντας υλικό µεγαλύτερου δείκτη διάθλασης κοντά στην επιφάνεια Θερµική εσω-διάχυση: Μεταλλικό υµένιο εναποτίθεται σε µονοκρύσταλλο LiNbO 3, ενώ παράλληλα ρέει αδρανές αέριο Αr, N 2, O 2, σε 1000 o C. Ως αποτέλεσµα το µέταλλο διαχέεται στην επιφάνεια δίνοντας υλικό µεγαλύτερου δείκτη διάθλασης. Ion-implantation (εµφύτευση ιόντων): Επιταχυνόµενα ιόντα ενέργειας 20 µε 300keV εµφυτεύονται στο υπόστρωµα έχοντας σαν αποτέλεσµα υλικό µεγαλύτερου δείκτη διάθλασης. Ανταλλαγή ιόντων: Η µέθοδος αυτή είναι εµβάπτυνση µονοκρύσταλλου LiNbO 3 σε τηγµένο αλάτι, όπως ΑgNO 3 και τηγµένο βενζοϊκό οξύ.
Pattern Generation. The interference of beams of coherent laser light produces standing electromagnetic waves, which can imprint regular patterns into the surface of photosensitive materials such as polymeric resists. Such maskless lithography is now being exploited commercially to control the optical properties of surfaces. This circular process, where optical beams modify matter to control light, has various applications in photonics, including production of linear gratings for distributed feedback lasers and wavelength division multiplexing. Twodimensional patterns can also be produced, even on lens surfaces with modest curvature. An example produced by Holographic Lithography Systems Inc. is shown in Figure. This particular "motheye" surface has a 300 nm pitch for the 500 nm deep structures. Surfaces coated in this manner have low reflectance, so these structures can replace conventional multilayer anti-reflection coatings. They have wide angular and spectral acceptance. It is quite possible that such patterned surfaces will be employed within future optical MEMS in order to improve their performance. Motheye structure shown at about 20,000 X magnification
LIGA is a process that uses a planar substrate, which has been coated with an X- ray sensitive photoresist. The resist is then patterned during exposure and etched to produce a three-dimensional structure. The etching may either be positive or negative depending on the photoresist and its development. Metal is then electroplated into the molds and the resist is etched away. The metal structure can serve either as the product, as in Figure 4, or as a mold for making plastic parts. This process can produce three-dimensional structures on the micron scale. It can also be modified in a variety of ways and combined with other MEMS production tools to make hybrid devices. The ability to make high aspect ratio structures is the unique characteristic of using X-rays to expose a photoresist, since the shorter wavelength X-rays cast sharp shadows with almost negligible diffractive blurring. An interesting modification of the LIGA process is the "X-ray lathe" that can be used to produce cylindrically-symmetric parts as well as non-symmetric parts [Feinerman et al. 1996]. The key difference with this variation is the substrate is not planar. A PMMA coated wire is rotated axially in a glass-blower's lathe at approximately 1 rpm. The X-ray beam is directed through a planar mask suspended above the rotating substrate. Mask patterns can be designed to make either binary steps or reducing radius structures. Mask translation in the axial direction can produce helical structures and translation in the perpendicular direction can produce lobed structures. Nickel gears manufacstructures can be electroplated and used in various applications such as waveguides, bearings, and gears. Nickel gears manufactured using LIGA process
Μη γραµµικά φαινόµενα... laser 800 nm, 30-200fs P= x E+ xe + x E + 2 3 0 1 2... Εστίαση του παλµού του laser στην υγρή ρητίνη ιαδικασία πολυµερισµού δύο φωτονίων Μετατροπή υγρής ρητίνης σε στερεή Αποµάκρυνση υγρής ρητίνης Opt lett/vol.21/no 21/p.1729/Nov 1,1996
Έχει διαστάσεις 10µm µήκος και 7µm ύψος µε ακρίβεια 120 nm! ιάρκεια κατασκευής 180 min Nature/vol. 412/p. 697/ 16 Aug. 2001 Laser Centrum of Hannover (height 10 µm)