A UNIDIRECTIONAL OUTPUT OPTICAL FREQUENCY-CONVERSION DEVICE WITH AN ASYMMETRIC-KAPPA DBR STRUCTURE

A novel optical frequency conversion device that successfully demonstr ates optical frequency conversion and unidirectional transmission of o ptical signals has been designed and fabricated. The device is compose d of a gain region and saturable absorber region with monolithically i ntegrated distributed Bragg reflector (DBR) mirrors with different cou pling coefficients. The device structure is optimized to achieve three functions: 1) unidirectional light output, 2) converted-light wavelen gth tuning, and 3) optically triggered optical frequency conversion. T he output power of converted light from the light input-end facet of t he device is 30 dB smaller than that from the output-end racet, and th e converted light wavelength can be scanned over 4 nm without a bias c urrent to the input-end DBR region, and it is widened to 7.8 nm by inj ecting current to that region. The device emits converted light only w hen light input is injected and optical signals are unidirectionally t ransmitted, and its response frequency is estimated to be 0.8 GHz.