Peripheral coupled waveguide (PCW) design has been deployed in InGaAsP multiple quantum-well (MQW) electroabsorption modulator (EAM) at 1.55-mum wavelength. PCW enhances the optical saturation power and reduces the optical insertion loss and the equivalent V-pi simultaneously. A radio-frequency link using a 1.3-mm-long lumped-element PCW EAM has achieved experimentally a link gain of -3 dB, at 500 MHz and at input optical power of 80 mW. The corresponding two-tone multioctave spurious-free dynamic range (SFDR) at the same bias is measured at 118 dB (.) Hz(2/3). The single-octave SFDR at the third-order null bias is 132 dB (.) Hz(4/5).

A novel electroabsorption modulator (EAM) using intrastep quantum wells (IQWs) and a single-sided large optical cavity waveguide is demonstrated to operate at up to 100 mW of input optical power. When the IQW EAM with uncoated facets is tested in an analog fiber link, the radio-frequency link gain reaches -16.1 dB at 100-mW optical power. We have measured a single-octave spurious-free dynamic range (SFDR) of 121 dB (.) Hz(4/5) and multioctave SFDR of 110 dB (.) Hz(2/3) for this EAM.

A novel, compact, and tunable lithium niobate (LN) planar waveguide loop structure composed of two Y junction reflectors is proposed for optical and radio frequency signal processing applications. The preliminary device shows a high quality factor of 6.5 x 10(4), due to the low propagation loss of the titanium-diffused LN waveguide. The tunability of the loop by electric field is estimated.