Structural influence of proton exchange on domain-inverted lithiumniobate revealed by means of selective etching

Selective etching is used to study the influence of different proton-exchange methods on the crystal structure of periodically domain-inverted lithium niobate. The annealed proton-exchange method is shown to interfere strongly with previously patterned domains. A less common graded proton-exchange method that leaves the ferroelectric domain structure intact is demonstrated     

Quasi-phase-matched blue light generation in bulk lithium niobate,electrically poled via periodic liquid electrodes

Periodic poling of z-cut lithium niobate is reliably achieved in 0.2 mm thick samples, patterned with photoresist on one face and subjected to pulsed electric fields via liquid electrodes. The acceptance bandwidth for third order second-harmonic generation reveals that the full 3.3 mm length contributes to the conversion     

Periodic domain inversion and generation of blue light in lithium tantalate waveguides

Generation of blue light from small solid-state light sources is a technological challenge with applications in many areas, among others optical data storage. The authors report frequency doubling using third-order quasi-phase matching in periodically domain-inverted lithium tantalate waveguides. Periodic proton exchange followed by heat treatment caused periodic domain inversion and waveguide formation in a single step. Infrared radiation from a dye laser was coupled through the waveguides and second-harmonic generation corresponding to third-order quasi-phase-matching was observed.<>     

Stimulated emission in Er:Ti:LiNbO/sub 3/ channel waveguides close to 1.53 mu m transition

Fabrication and characterisation of Er:Ti:LiNbO/sub 3/ channel waveguides is reported. A lifetime of 2.4+or-0.2 ms has been measured for the /sup 4/I/sub 13/2/ level. In a pump and probe experiment using a high power InGaAsP laser and a tunable DBR laser, a signal increase of 0.75 dB for a transmitted pump power of 4.8 mW was demonstrated.<>     

Visible laser sources based on frequency doubling in nonlinearwaveguides

This paper reviews nonlinear quasi-phase-matching (QPM) waveguides and laser diodes with application to conversion of infrared laser diode wavelengths to the visible. The discussion of nonlinear QPM waveguides includes Ti-diffusion poled and E-field poled LiNbO₃ and KTP waveguides. Up to 25 mW of blue output power has been demonstrated for 120-mW infrared power injected into a nonlinear waveguide. Semiconductor laser sources suitable for frequency doubling are discussed, including distributed Bragg reflection (DBR) lasers operating at up to 200 mW output power, master oscillator power amplifiers with over 1 W output power, and wavelength-tunable flared semiconductor lasers with over 0.5 W output. A compact blue laser with 1-4 mW output power at 425-nm wavelength has been demonstrated based on a DBR laser frequency doubled in a nonlinear waveguide     

Wet etching of proton-exchanged lithium niobate-a novel processingtechnique

A novel and simple method to etch lithium niobate is reported. It was found that proton exchanged areas on the c⁺-face of the crystal can be etched away using a mixture of HF:HNO₃ while the unexchanged regions are left untouched. The method can be used as a tool for studies of the proton exchange process, as well as to form three-dimensional structures     

Large-scale photonic integrated circuits

100-Gb/s dense wavelength division multiplexed (DWDM) transmitter and receiver photonic integrated circuits (PICs) are demonstrated. The transmitter is realized through the integration of over 50 discrete functions onto a single monolithic InP chip. The resultant DWDM PICs are capable of simultaneously transmitting and receiving ten wavelengths at 10 Gb/s on a DWDM wavelength grid. Optical system performance results across a representative DWDM long-haul link are presented for a next-generation optical transport system using these large-scale PICs. The large-scale PIC enables significant reductions in cost, packaging complexity, size, fiber coupling, and power consumption.     

Large-Scale InP Photonic Integrated Circuits: Enabling Efficient Scaling of Optical Transport Networks

An overview of commercially available large-scale photonic integrated circuits (PICs) in indium phosphide is provided. Results of 100-Gb/s PICs that are field-deployed in wavelength-division-multiplexing (WDM) networks is provided, along with development results showing scaling of both channel count and channel bit rate to implement next-generation PICs with an aggregate capacity of 1.6 Tb/s. Use of PIC-enabled WDM systems allows affordable optical-electrical-optical (OEO) conversion and the implementation of "digital" optical networks with enhanced sub-wavelength reconfigurable bandwidth management, digital performance monitoring, and protection features. PICs will enable the continued capacity scaling required for next-generation IP core networks and support of high-bandwith 40-G and 100-GbE service connectivity between core routers     

Blue light generated by frequency doubling of laser diode light ina lithium niobate channel waveguide

Blue light was generated in a LiNbO₃ channel waveguide by frequency doubling radiation from a laser diode in a guided to guided wave interaction, utilizing first-order quasi-phase-matching in a periodically domain inverted structure. A fabrication method that does not depend on the use of titanium was used. A periodic pattern of silicon oxide on the positive c-face of LiNbO₃ was used in combination with a heat treatment to achieve a periodic outdiffusion and domain reversal in the surface layer. A channel guide was subsequently formed by proton exchange