Multigigabit multichannel optical interconnection module for broadband switching system

We propose 400-Gb/s (16 × 25 Gb/s) optical transmitter and receiver modules for on-board interconnects using polymer waveguide (PWG) arrays. Four four-channel vertical cavity surface emitting laser and PIN photodiode arrays are used in the optical transmitter and receiver modules. A 16-channel PWG array with a length of 140 mm and a pitch of 62.5 μm is used as a short-reach optical signal transmission medium in the module. The 25-Gb/s optical eye diagrams of the all output channels utilize PWG transmissions and exhibit good performance in the transmitter module, with a signal-to-noise ratio (SNR) of over 8.01, peak-to-peak time jitter below 11.70 ps, and mask margin of over 31.5%. In the best-performance channel of the receiver module, the peak-to-peak time jitter and SNR of the eye diagram are 10.34 ps and 10.76, respectively, and the receiver sensitivity is approximately −2.6-dBm under a bit error rate of 10−12. The optical transmitter and receiver modules utilizing PWG transmissions were designed and fabricated to realize 400-Gb/s on-board interconnects.

We developed transmitter and receiver modules with Ti:PPLN waveguide operated as difference frequency generator to convert a signal (lambda <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> ~ 1550 nm) to the mid infrared (lambda <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</sub> ~ 3800 nm) and back again.

Compact optical module packages for use as 156 Mbps optical interfaces have been developed by incorporating passive alignment techniques. In this approach, a laser chip and a fiber are aligned on a V-grooved silicon substrate by flip-chip bonding. The silicon substrates have been fabricated by conventional silicon processing and micro-machining technologies. A new feature of our fabrication technique is to implement a self-alignment principle for the formation of V-grooves and solder bumps, which eliminates a registration error from the individual process. The laser diode and photo diode submodules, assembled on silicon substrates, exhibited 4-6% and about 80% coupling efficiencies, respectively. The fabricated proto-type transmitter and receiver module packages have a very compact size of 5 cc each and showed adequate performance satisfying the requirement for optical subscriber transmitter and receiver modules.

Modeling behavior of broadband (30-1000 MHz) frequency modulated near infrared photons through a multilayer phantom is of interest to optical bio-imaging research. Photon dynamics in phantom are predicted using three-dimension (3D) finite element numerical simulation and are related to the measured insertion loss and phase for a given human head geometry in this paper based on three layers of phantom each with distinct optical parameter properties. Simulation and experimental results are achieved for single, two, and three layers solid phantoms using COMSOL (COMSOL AB, Tegnérgatan 23, SE-111 40, Stockholm, Sweden) (for FEM) simulation and custom-designed broadband free space optical transmitter (Tx) and receiver (Rx) modules that are developed for photon migration at wavelengths of 680, 795, and 850 nm. Standard error is used to compute error between two-dimension and 3D FE modeling along with experimental results by fitting experimental data to the functional form of afrequency+b. Error results are shown at narrowband and broadband frequency modulation. Confidence in numerical modeling of the photonic behavior using 3D FEM for human head has been established here by comparing the reflection mode's experimental results with the predictions made by COMSOL for known commercial solid brain phantoms.

This paper presents a novel method for early detection of hematomas using highly sensitive optical fNIR imaging methods based on broadband photon migration. The NIR experimental measurements of inhomogeneous multi-layer phantoms representing human head are compared to 3D numerical modeling over broadband frequencies of 30–1000 MHz. A finite element method (FEM) simulation of the head phantom are compared to measurements of insertion loss and phase using custom-designed broadband free space optical transmitter (Tx) and receiver (Rx) modules that are developed for photon migration at wavelengths of 670 nm, 795 nm, 850 nm, though results of 670 nm are discussed here. Standard error is used to compute error between 3D FEM modeling and experimental measurements by fitting experimental data to the asqrt {frequency} + b . Error results are shown at narrowband and broadband frequency modulation in order to have confidence in 3D numerical modeling. A novel method is established here to identify presence of hematoma based on first and second derivatives of changes in insertion loss and phase (∆IL and ∆IP), where frequency modulated photons sensitive to different sizes of hematoma is identified for wavelength of 670 nm. The high accuracy of this comparison provides confidence in optical bio-imaging and its eventual application to TBI detection.

A compact 10-Gb/s optical transmitter module with low-chip output was developed by using a monolithically integrated electroabsorption modulator with a DFB (distributed feedback) laser. A novel optical coupling scheme was used which involves a unique optical isolator with a photodiode for output power monitoring, and a thermoelectric cooler mounted in the package to achieve thermally stable module operation. The module can be operated at a bit rate of more than 10 Gb/s at 1.55 mu m and shows a high modulated output power of -1 dBm with a low optical coupling loss of 3.2 dB between chip and fiber. Because its wavelength chirping under high-speed modulation is small, this module is promising for multigigabit intensity modulation and direct detection (IM-DD) optical transmission systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The QSFP interface is used as the input port in the design of 4*10GHz optical transmitter module. It will inevitably lead to impedance mismatch, resonance and signal distortion. Using the three-step optimization, in DC-10GHz bandwidth, the insertion loss S21 is greater than -2dB, and the echo loss S11 is less than -10dB, the S-parameter resonances were largely mitigated. Finally, The whole schematic link of transmitter module with the optimized QSFP interface is modeled and simulated by ADS, the gain flatness of the transmission link is within ±4dB, and shows that the optimized QSFP interface has a perfect electrical performance in the optical transmitter module.

In this paper, we propose a high-speed optical receiver module with four channels. The optical receiver module was composed of a four-channel PIN photodiode array and a four-channel linear transimpedance amplifier on a six-layer printed circuit board (PCB). The top and bottom layers of the PCB were used as the high-speed layers. The grounded coplanar waveguide structure was designed on the PCB for high-speed data transmissions. The interface of the optical receiver module was designed as the QSFP28 pin definition. According to the eye diagram and bit-error rate measurements, the optical receiver module can be achieved 160 Gb/s NRZ and 200 Gb/s PAM4 transmissions over 1 km single mode fiber [1].

This paper describes the 2.5-Gb/s optical receiver module using a one-chip receiver IC for an ultrabroadband optical access system. The IC provides reshaping, retiming and regenerating functions required for an optical receiver. The reshaping is performed by a preamplifier and a limiter amplifier using a reference voltage generator. Retiming and regenerating are accomplished by a clock-and-data recovery circuit using a phase comparator combined with a regenerator. The IC and an APD are packaged in a compact ceramic package using passive alignment technology. The module has a size of 14/spl times/19 mm, and a power consumption of 450 mW at a +3.3 V supply voltage.

A multi-Gbit/s transmitter module with a high-speed hetero-MISFET driver IC and a multi-quantum-well DFB-LD has been developed. A miniaturised module with bare chip mounting of the LD and the driver IC made 10 Gbit/s high-speed operation possible. Using this module, an optical fibre transmission experiment has been successfully carried out over 40 km.

This paper describes the development of wavegude modules for 120-GHz wireless applications. The MMIC in the modules were fabricated using 0.1-mum-gate InP-HEMTs and coplanar waveguides. The transmitter (Tx) module contains a Tx MMIC and a multiplier MMIC for carrier generation. The Tx MMIC contains a frequency doubler, ASK modulator, and an amplifier. Output power of the Tx module is 0 dBm. The receiver (Rx) module contains a Rx MMIC with a low-noise amplifier and ASK demodulator. For high-power operation of transmitter, we developed a power amplifier (PA) waveguide module that attaches to the Tx module. This PA module contains one-chip PA MMIC, and has 13-dBm output power with associated gain of 10.5 dB at 125 GHz. A back-to-back test of the Tx/Rx modules with and without the PA module have shown it to be fully functional at 10-Gbit/s data rate with BER = 1e-10 at -34.5-dBm and -36.1-dBm input powers for the receiver, respectively

Authors propose a hardware based approach for reliable encryption in wireless network using Cellular Automata (CA). Distinct layers of encryption have been utilized in proposed model for enhancing data security. Transmitter and receiver modules are designed for performing state transition based encrypted activities. Transmitter module is required for capturing environmental turbulences (noise) from a specific geographical location and send encrypted signal to receiver module through wireless network. Receiver module analyses received signal after decryption for desired activities based on real time situations. Different hardware components are selected and compared based on market study targeting efficient construction of proposed modules. Time complexity and code break complexity are measured using different key lengths, keysets, and data sizes for proposed CA based encryption scheme achieving unique results in hardware based cryptography system. Encryption key length, index, and keyset are required for computing code break complexity in design model. Large data size is effectively managed to calculate protection ratio and reliability factor for realizing efficient protectiveness and accuracy. Comparative study between existing encryption technique and proposed CA based encryption technique is established based on time complexity and code break complexity.

The authors have developed a very compact set of 10 Gbit/s optical transceiver and receiver modules, each 80/spl times/120/spl times/20 mm/sup 3/. A novel cooling structure based on a high-performance heat-transfer device and micro-fans, achieving a heat resistance value of 1.8/spl deg/ C/W, enables the high-density heat generation to be handled in such a small module.

The asynchronous transfer mode (ATM) has become the subject of intense interest across all segments of the telecommunications and computer industry. State-of-the-art multiplexing and switching technologies form the basis of ATM's ability to deliver different types of information (e.g., voice, data, audio, video and graphics) at gigabit speeds. ATM networks rely heavily on the efficiency and speed of their switching fabrics. In the last few years, heavy research has been conducted in the design of new ATM switching fabrics. We examine the B-tree fault-tolerant ATM switch, acknowledged to be one of the most efficient ATM switch. We show several of its shortcomings, one of which is that it does not resolve internal conflicts of data packets. We (1) extensively study the B-tree switch (2) analyze the different buffering methods that would be suitable for our design, (3) analyze the different traffic models to reflect real-time traffic, (4) exploit the information from above to design a more fault-tolerant switch, and (5) conduct extensive simulation to prove the efficacy of our design.

This paper considers a multistage interconnection network based on the Indirect Star Graph topology as a candidate for an ATM (Asynchronous Transfer Mode) switch fabric. We consider both buffered and unbuffered versions of the indirect star. The performance of three existing routing algorithms is studied, and it is found that the packet acceptance probability offered by these algorithms is unsatisfactory. We propose two solutions to alleviate the problem: a modification of the indirect star topology, which we call Star Net; and an adaptive routing algorithm based on the concept of packet priorities. We study the performance of the proposed performance enhancement schemes through simulation. >