Integrated polymer photonics brings low cost and high fabrication flexibility to optoelectronic industry. However, this platform needs to overcome several issues to be effective enough for practical applications. In this work, we experimentally demonstrate a decrease of propagation losses and polarization sensitivity of polymer waveguide-based devices as a result of thermal treatment. Heating of poly(methyl methacrylate) strip optical waveguides above the glass transition temperature initiates a waveguide surface reflow due to a decrease of the polymer viscosity and surface tension energy. This results in a decrease of surface roughness and shape change from rectangular to cylindrical. Thus, scattering losses and polarization sensitivity are minimized. IEEE

To tackle the continued increase in capacity demand in optical access, self-homodyne coherent detection (SHCD) is being considered as a candidate solution, utilizing a spatial division multiplexing (SDM) in a low-crosstalk multicore fiber (MCF) [1, 2] and high-order modulation formats such as quadrature phase-shift keying (QPSK), 16-levels quadrature amplitude modulation (16-QAM) or even 64-levels QAM (64-QAM) . The latest imposes strict requirements on both the performance of digital signal processing (DSP) and the spectral purity of the free running lasers [4–6]. Although a SHCD scheme relaxes the laser linewidth requirements, eliminates the need for a carrier frequency tracking, the necessity for a carrier phase estimation remains if high-order constellations are considered. The reasons for that are (1) residual phase noise in a system and (2) a closer location of the constellation points in the complex plane, which leads to a significantly lower phase noise tolerance as compared to QPSK or even 16-QAM signals . Therefore, it is of crucial importance to propose a low-complexity (and low-latency) phase estimation algorithms for these scenarios as well, especially because traditional algorithms cannot be directly employed for 64QAM. During this presentation,

first, we overview our recent activities on designing and experimental validation of a high-performance and a low-complexity DSP block, focusing on carrier phase recovery (CPR) suitable for circular and square m-QAM constellations. For more information about the efficient CPR schemes for m-QAM, we recommend the

OFC2017 and ACP2017 proceedings.

Second, after the efficient CPR scheme is explained, we provide an insight into a solution of SDM-based optical access network where self-homodyne coherent detection (SHCD) scheme with our novel low-complexity CPR is implemented for a 28-Gbaud 16-QAM and 64- QAM transmission in downstream links with a goal to improve their spectral efficiency and to increase a phase-noise tolerance, which paves the way towards higher cost-efficiency. The proposed architecture together with the experimental demonstration is given in

CLEO2018 conference proceedings

We demonstrate 100 Gbaud 4PAM transmission over 400 meters SMF with monolithically integrated 1550 nm DFB-TWEAM having 100 GHz 3-dB bandwidth with 2 dB ripple. We evaluate its capabilities to enable two lanes 400 GbE client-side links for optical interconnects. © 2017 IEEE.

We experimentally demonstrate a DMT transmission system with 1.55-μm EML using nonlinearity-aware time domain super-Nyquist image induced aliasing. Compared with linear equalization, the capacity is improved by ∼16.8%(33.1%) with proposed method for 4(40) km transmission.

We experimentally demonstrate a DMT transmission system with 1.55-μm EML using nonlinearity-aware time domain super-Nyquist image induced aliasing. Compared with linear equalization, the capacity is improved by ~16.8%(33.1%) with proposed method for 4(40) km transmission. © 2017 OSA.

We report on the first experimental demonstration of 200-Gbps (net rate 166.7-Gbps) 1.55-μm DMT IMDD transmission over 1.6 km fiber using a single monolithically-integrated-EML, DAC and photodiode, achieving an effective electrical spectrum efficiency of 4.93 bit/s/Hz. © 2017 IEEE.

The inherent discrete phase search nature of the conventional blind phase search (C-BPS) algorithm is found to introduce angular quantization noise in its phase noise estimator. The angular quantization noise found in the C-BPS is shown to limit its achievable performance and its potential low complexity implementation. A novel filtered BPS algorithm (F-BPS) is proposed and demonstrated to mitigate this quantization noise by performing a low pass filter operation on the C-BPS phase noise estimator. The improved performance of the proposed F-BPS algorithm makes it possible to significantly reduce the number of necessary test phases to achieve the C-BPS performance, thereby allowing for a drastic reduction of its practical implementation complexity. The proposed F-BPS scheme performance is evaluated on a 28-Gbaud 16QAM and 64QAM both in simulations and experimentally. Results confirm a substantial improvement of the performance along with a significant reduction of its potential implementation complexity compared to that of the C-BPS.

Heating of poly(methyl methacrylate) ridge optical waveguides slightly above glass transition temperature minimizes surface roughness and provides cylindrical shape. We experimentally demonstrate propagation loss decrease and polarization insensitivity as a result of waveguide thermal treatment.

Heating of poly(methyl methacrylate) ridge optical waveguides slightly above glass transition temperature minimizes surface roughness and provides cylindrical shape. We experimentally demonstrate propagation loss decrease and polarization insensitivity as a result of waveguide thermal treatment.

We experimentally evaluate high-speed intensity modulation/direct detection (IM/DD) transmissions with a 1.55-μ text broadband electro-Absorption modulated laser and pulse amplitude modulations (PAM). We demonstrate 80 Gb/s/ λ PAM-4 and 96 Gb/s/ λ PAM-8 transmissions with low-complexity digital equalizers at the receiver. Performance comparison with different types of equalizers are performed, including linear symbol-spaced feed-forward equalizer (FFE), fractional (half-symbol) spaced FFE and decision feedback equalizer (DFE), with different tap number. It is found that for both cases, a 6-Tap symbol-spaced FFE is sufficient to achieve a stable performance with bit-error-rate below the 7% overhead hard decision forward error correction (7%-OH HD-FEC) threshold over a 4 km standard single mode fiber link. Practical considerations including comparison between adaptive and static equalizer implementation and tolerable fiber chromatic dispersion are discussed.