Colorless coherent receiver using 3x3 coupler hybrids and single-ended detection

Abstract

We demonstrate a single-ended colorless coherent receiver using symmetric 3x3 couplers for optical hybrids. We show that the receiver can achieve colorless reception of fifty-five 112-Gb/s polarization-division-multiplexed quadrature-phase-shift-keyed (PDM-QPSK) channels with less than 1-dB penalty in the back-to-back operation. The receiver also works well in a long-haul wavelength-division-multiplexed (WDM) transmission system over 2560-km TrueWave® REACH fiber.

Performance comparison between direct phase modulated DFB and RSOA for cost effective transmitter in udWDM-PONs

“…The electrical signal was amplified, and then sampled and digitally post-processed with a 50 GSa/s real-time oscilloscope. The samples were low-pass filtered and combined as in [10] for obtaining the I and Q components. The signal was differentially decoded with a delay and multiply block to recover the data.…”

Low cost coherent receivers for UD-WDM NRZ systems in access networks

“…This receiver can be realized in many ways [7]: we focused on the implementation which fits well the low-cost and simplicity criteria required by the COCONUT architecture. It is based on a 3×3 power splitter (which acts as a 120° optical hybrid coupler), followed by 3 photodiodes and by an analogue processing stage, where the photodiode currents are basically squared and summed together, thus yielding the desired signal [8]. The phase diversity intradyne approach, based on a symmetric 3×3 coupler, has been studied both theoretically and experimentally [5].…”

Experiment investigation of nonlinear distortion in QAM constellation due to imbalance in intradyne coherent receiver

“…It provides a promising way to improve receiver sensitivity, increase spectral efficiency, enable complicated modulation formats, and utilize electronic equalization. In order to suppress the interference from direct-detection terms, a high common-mode-rejection ratio (CMRR) and/or a high power difference between signal and local oscillator (LO) is essential for balanced coherent receivers to be used as colorless receivers without deployment of additional demultiplexing filters [2][3]. Although balanced receivers can suppress this kind of interference, some interference will be present due to the imperfect balancing in the receivers.…”