Balanced Photodiodes Research Articles

First system experiments with a monolithically integrated tunable polarization diversity heterodyne receiver OEIC on InP

System performance of an integrated polarization diversity heterodyne receiver optoelectronic IC (OEIC) is reported. The OEIC is monolithically integrated on InP. It includes a tunable 4 section DBR laser (quasi continuous tuning range 3.5 nm) and balanced photodiodes. The packaged OEIC is supplied with a fiber pigtail. Stable and polarization independent operation is achieved without any tendency for a bit error floor. The sensitivity at 1550.2 nm is -33.5 dBm at a bitrate of 140 Mbit/s. The performance of the OEIC based receiver is verified by operating in an experimental OFDM-TV distribution system with 4 channels. >

InP-based 10-GHz bandwidth polarization diversity heterodyne photoreceiver with electrooptical adjustability

A polarization diversity optical receiver, integrated with two pairs of balanced photodiodes in the InP/InGaAsP material system, is described. This circuit includes two polarization splitters based on modal birefringence and, for the first time, adjustable 3-dB TE and TM directional couplers (relaxing fabrication tolerances). On-chip losses are below 2.5 dB (TE) and 5.5 dB (TM). Waveguide to PIN coupling efficiency is >95%. Polarization crosstalk is in the 9-10-dB range, 3-dB couplers balance can be recovered, and common mode rejection ratio (CMRR) lower than -30 dB is obtained and remains below -20 dB over 6 GHz. Balanced receiver circuit 3-dB bandwidth is in excess of 10 GHz.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Noise suppression characteristics of InP-based monolithically integrated guided wave balanced photodiodes

Measurements were made of the noise suppression and signal enhancement properties of dual In/sub 0.53/Ga/sub 0.47/As-InP metal-semiconductor-metal (MSM) photodiodes integrated with a leaky mode In/sub 0.52/Al/sub 0.48/As waveguide directional coupler, and an electro-optic phase shifter. The experiments were done with a 1.3- mu m laser as the local oscillator. A noise suppression of 11 dB and signal enhancement of 1.3 dB were recorded for the MSM photodiodes.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Reaching the shot noise limit in the polarization measurement of individual nanosecond light pulses

Using a balanced dual-channel polarimeter and fast photodiodes coupled to low-noise charge integrators, we demonstrate precise polarization detection of individual light pulses in the nanosecond time-scale, with a noise very close to the shot noise limit. This result has important implications for various precision measurements such as atomic parity violation, squeezing at short time scales, and possibly parity violation with squeezed light.

Balanced dual photodiodes integrated with a 3 dB directional coupler for coherent lightwave receivers

A photonic integrated circuit consisting of a 3 dB directional coupler and two GaInAs pin photodiodes connected in series at the output of the coupler has been fabricated. The photodiodes have typical dark currents of approximately 3 nA at a reverse bias of 8 V, with more than 1 MΩ isolation. Symmetrical operating characteristics with respect to the launching direction have been achieved.