Continuous wave and passively Q-switched Nd:YAG laser with a multisegmented crystal diode-pumped at 885 nm.

Mitigation of thermal effects in a 1064 nm Nd:YAG laser is demonstrated through the combination of a multisegmented crystal rod and upper laser level pumping by diode at 885 nm toward optimizing the generated beam profile. Continuous wave (cw) and passively Q-switched operation is demonstrated obtaining 7.5 W and 2 mJ at 100 Hz, respectively, with excellent beam quality. Comparison with a conventional uniform Nd:YAG rod reveals improvements of up to 64% in optical conversion efficiency and 67% in output power for retaining the beam quality. Thermal-lensing measurements validate the improved thermal management in the multisegmented crystal in conjunction with M-square values better than 1.3.

Multi-format all-optical processing based on a large-scale, hybridly integrated photonic circuit.

We investigate through numerical studies and experiments the performance of a large scale, silica-on-silicon photonic integrated circuit for multi-format regeneration and wavelength-conversion. The circuit encompasses a monolithically integrated array of four SOAs inside two parallel Mach-Zehnder structures, four delay interferometers and a large number of silica waveguides and couplers. Exploiting phase-incoherent techniques, the circuit is capable of processing OOK signals at variable bit rates, DPSK signals at 22 or 44 Gb/s and DQPSK signals at 44 Gbaud. Simulation studies reveal the wavelength-conversion potential of the circuit with enhanced regenerative capabilities for OOK and DPSK modulation formats and acceptable quality degradation for DQPSK format. Regeneration of 22 Gb/s OOK signals with amplified spontaneous emission (ASE) noise and DPSK data signals degraded with amplitude, phase and ASE noise is experimentally validated demonstrating a power penalty improvement up to 1.5 dB.

Packet-level synchronization scheme for optical packet switched network nodes.

We demonstrate an all-optical, self-synchronization scheme for optical packet switched network nodes. It provides both the packet clock signal and the packet beginning, marker pulse. The circuit uses two hybridly integrated MZI switches and has been evaluated with synchronous, asynchronous and variable length, data packets at 10 Gb/s. It is compact and requires relatively low energies to operate.

Compact all-optical packet clock and data recovery circuit using generic integrated MZI switches.

We present and evaluate a compact, all-optical Clock and Data Recovery (CDR) circuit based on integrated Mach Zehnder interferometric switches. Successful operation for short packet-mode traffic of variable length and phase alignment is demonstrated. The acquired clock signal rises within 2 bits and decays within 15 bits, irrespective of packet length and phase. Error-free operation is demonstrated at 10 Gb/s.