Low-cost optical sub-assemblies for metro access applications
The fiber optic communications industry is experiencing significant change as datacom 10 Gb/s Ethernet (10 GbE) networks merge with telecom SONET 10G networks in the drive to reach metro access applications. Lower data rate (1G Ethernet, 1G and 2G fiber channel, and SONET OC-48) applications have already merged to some extent as various versions are available within the SFF or SFP standard transceiver form factors. Traditional 10 Gb/s optical subassemblies (OSAs), developed for SONET OC-192 applications, used variations of the expensive butterfly type package. However, smaller form factor modules (such as the XFP that uses SFF optical connectors and LC duplex optical connectors) require much smaller OSAs. To meet the size limitation of packaging 10G OSAs into the XFP transceiver and also meet the 10 GbE market challenge of providing low-cost solutions, new 10 Gb/s OSA components are needed.
Compact TO-CAN Header With Bandwidth Excess 40 GHz
A large bandwidth transistor outline (TO)-CAN header used in a low cost laser module was designed through a three dimensional full wave electromagnetic simulation and demonstrated by a direct measurement technique. The simulation results show that the proposed TO-CAN header provides a resonance-free transmission bandwidth in excess of 40 GHz with a reflection loss of 25 GHz under -10 dB with an ideal 50 Ω terminal. A pair of specially designed K type adaptors was used to accommodate the TO-CAN header for the high frequency measurements. This is a direct contact setup, without extra parasitic effects, and allowing a near resonance-free measurement. The experimental results are in good agreement with simulated results in the frequency range up to 40 GHz. A time-domain reflectometry measurement and a 40 Gbit/s eye diagram test were made to verify the performance. In addition, a laser module packaged with the TO-CAN header is proposed. By taking the bonding wires into account, the simulated transmission bandwidth of the module is over 35 GHz and a clear 25 Gbit/s eye diagram is obtained. This cost effective package solution of laser module can be applied in the next generation 100 Gigabit Ethernet (100 GbE) network.
PULSE: a high-repetition-rate linac driver for x-ray FELs
We describe a staged concept for a linac-based freeelectron laser providing coherent tuneable VUV and soft X-ray output with pulse lengths down to 10 fs or less. Use of 1.3 GHz cryomodules operated with CW RF will allow flexible pulse patterns at potentially very high repetition rates up to 1 MHz. We consider the options for FELs that may be included in a facility of this type.