Technology for flexibly monitoring optical signal quality in transparent optical communications [Invited]

2007 ◽  
Vol 6 (11) ◽  
pp. 1229 ◽  
Author(s):  
Ippei Shake ◽  
Hidehiko Takara ◽  
Satoki Kawanishi
Keyword(s):  
Optical Communications ◽  
Optical Signal ◽  
Signal Quality

scholarly journals The Optical Signal-to-Crosstalk Ratio for the MBA(N, e, g) Switching Fabric †

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1534
Author(s):  
Remigiusz Rajewski
Keyword(s):  
Optical Switching ◽  
Essential Feature ◽  
Optical Signal ◽  
Point Of View ◽  
Signal Quality ◽  
Switching Networks ◽  
Optical Elements ◽  
Optical Signals ◽  
Switching Fabric

The banyan-type switching networks, well known in switching theory and called the logdN switching fabrics, are composed of symmetrical switching elements of size d×d. In turn, the modified baseline architecture, called the MBA(N,e,g), is only partially built from symmetrical optical switching elements, and it is constructed mostly from asymmetrical optical switching elements. Recently, it was shown that the MBA(N,e,g) structure requires a lower number of passive as well as active optical elements than the banyan-type switching fabric of the same capacity and functionality, which makes it an attractive solution. However, the optical signal-to-crosstalk ratio for the MBA(N,e,g) was not investigated before. Therefore, in this paper, the optical signal-to-crosstalk ratio in the MBA(N,e,g) was determined. Such crosstalk influences the output signal’s quality. Thus, if such crosstalk is lower, the signal quality is better. The switching fabric proposed in the author’s previous work has lower optical signal losses than a typical Beneš and banyan-type switching networks of this same capacity and functionality, which gives better quality of transmitted optical signals at the switching node’s output. The investigated MBA(N,e,g) architecture also contains one stage fewer than banyan-type network of the same capacity, which is an essential feature from the optical switching point of view.

Light-triggered Silicon-carbon Pi'npin Devices for Optical Communications: Theoretical and Electrical Approaches

2010 ◽  
Vol 1245 ◽  
Author(s):  
Manuela Vieira ◽  
M. A. Vieira ◽  
João Costa ◽  
Paula Louro ◽  
Miguel Fernandes ◽  
...  
Keyword(s):  
Optical Communications ◽  
Incident Light ◽  
Optical Signal ◽  
Nonlinear Dependence ◽  
Light Wavelength ◽  
Electrical Model ◽  
Silicon Carbon ◽  
Light Generation ◽  
Incident Light Wavelength ◽  
Device Operation

AbstractIn this paper a light-activated multiplexer/demultiplexer silicon-carbon device is analysed. An electrical model for the device operation is presented and used to compare output signals with experimental data. An algorithm that takes into accounts the voltage and the optical bias controlled sensitivities is developed. The device is a double pi'n/pin a-SiC:H heterostructure with two optical gate connections for light triggering in different spectral regions. Multiple monochromatic pulsed communication channels were transmitted together, each one with a specific bit sequence. The combined optical signal was analyzed by reading out, under different applied voltages and optical bias, the generated photocurrent across the device. Experimental and simulated results show that the output multiplexed signal has a strong nonlinear dependence on the light absorption profile, i.e. on the incident light wavelength, bit rate and intensity under unbalanced light generation of carriers. By switching between positive and negative voltages the input channels can be recovered or removed from the output signal.

Optical signal quality monitoring method based on optical sampling

1998 ◽  
Vol 34 (22) ◽  
pp. 2152 ◽  
Author(s):  
I. Shake ◽  
H. Takara ◽  
S. Kawanishi ◽  
Y. Yamabayashi
Keyword(s):  
Optical Signal ◽  
Quality Monitoring ◽  
Signal Quality ◽  
Monitoring Method ◽  
Optical Sampling

scholarly journals Optical Transmitters without Driver Amplifiers—Optimal Operation Conditions

2018 ◽  
Vol 8 (9) ◽  
pp. 1652 ◽  
Author(s):  
Arne Josten ◽  
Benedikt Baeuerle ◽  
Romain Bonjour ◽  
Wolfgang Heni ◽  
Juerg Leuthold
Keyword(s):  
Single Channel ◽  
Direct Detection ◽  
Signal To Noise Ratio ◽  
Optical Signal ◽  
Optimal Operation ◽  
Signal Quality ◽  
Root Mean Square Amplitude ◽  
Operation Conditions ◽  
Communication Links ◽  
Eye Opening

An important challenge in optical communications is the generation of highest-quality waveforms with a Mach–Zehnder modulator with a limited electrical swing (Vpp). For this, we discuss, under limited Vpp, the influence of the waveform design on the root-mean-square amplitude, and thus, the optical signal quality. We discuss the influence of the pulse shape, clipping, and digital pre-distortion on the signal quality after the electrical-to-optical conversion. Our simulations and experiments, e.g., suggest that pre-distortion comes at the expense of electrical swing of the eye-opening and results in a lower optical signal-to-noise ratio (OSNR). Conversely, digital post-distortion provides operation with larger eye-openings, and therefore, provides an SNR increase of at least 0.5 dB. Furthermore, we find that increasing the roll-off factor increases the electrical swing of the eye-opening. However, there is negligible benefit of increasing the roll-off factor of square-root-raised-cosine pulse shaped signals beyond 0.4. The findings are of interest for single-channel intensity modulation and direct detection (IM/DD) links, as well as optical coherent communication links.

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