Widely tunable grating-assisted heterogeneous silicon nitride/polymer waveguide coupler.

A grating-assisted heterogeneous waveguide coupler is designed, fabricated, and demonstrated on a polymer platform. The parallel silicon nitrite core and polymer core are horizontally placed with vertical center alignment accuracy of ±5 nm. The coupler is differentially thermally tunable. The temperature gradient distribution, introduced by offset micro-heaters, is studied by thermal simulations. A total tuning range of 82 nm is demonstrated experimentally.

Photonic-integrated circuit for continuous-wave THz generation.

We demonstrate a photonic-integrated circuit for continuous-wave (cw) terahertz (THz) generation. By comprising two lasers and an optical phase modulator on a single chip, the full control of the THz signal is enabled via a unique bidirectional operation technique. Integrated heaters allow for continuous tuning of the THz frequency over 570 GHz. Applied to a coherent cw THz photomixing system operated at 1.5 µm optical wavelength, we reach a signal-to-noise ratio of 44 dB at 1.25 THz, which is identical to the performance of a standard system based on discrete components.

Serial 100 Gb/s connectivity based on polymer photonics and InP-DHBT electronics.

We demonstrate the first integrated transmitter for serial 100 Gb/s NRZ-OOK modulation in datacom and telecom applications. The transmitter relies on the use of an electro-optic polymer modulator and the hybrid integration of an InP laser diode and InP-DHBT electronics with the polymer board. Evaluation is made at 80 and 100 Gb/s through eye-diagrams and BER measurements using a receiver module that integrates a pin-photodiode and an electrical 1:2 demultiplexer. Error-free performance is confirmed both at 80 and 100 Gb/s revealing the viability of the approach and the potential of the technology.

Polarization insensitive 25-Gbaud direct D(Q)PSK receiver based on polymer planar lightwave hybrid integration platform.

We report a direct DPSK receiver based on polymer planar lightwave circuit technology, which incorporates a 2x25 GHz photodiode (PD) array hybridly integrated via 45° mirrors. In this direct DPSK receiver, a half-wave plate and heating electrodes are implemented to eliminate the polarization-dependent frequency-shift (PDFS) of the delay-line interferometer (DLI). By applying a proper heating current, a residual PDFS of practically zero at 1550 nm and within ±125 MHz was achieved over the full C-band. Integrated with the PD array, the peak responsivity is ~0.14 A/W for orthogonal polarizations over the C-band. To characterize this direct receiver, we introduce an adapted common-mode rejection ratio (CMRR), which takes into account the unequal responsivities of the PDs, the uneven split of the input power by the DLI, the phase error and the extinction ratio of the DLI. The measured CMRR under DC condition is below -20 dB over the C-band.

Dual-quadrature coherent receiver for 100G Ethernet applications based on polymer planar lightwave circuit.

A dual-quadrature coherent receiver based on a polymer planar lightwave circuit (PLC) is presented. This receiver comprises two separate optical 90°-hybrid chips made of polymer waveguides and hybridly integrated with InGaAs/InP photodiode (PD) arrays. The packaged receiver was successfully operated in 112 Gbit/s dual-polarization quadrature phase-shift keying (QPSK) transmission experiments. In back-to-back configuration the OSNR requirement for a BER value of 10(-3) was 15.1 dB which has to be compared to a theoretical limit of 13.8 dB.