InP transistor shifts phase from test to telecom
Normally, using a product outside of its intended application is an excellent way to invalidate its warranty, but for GigOptix it has presented a market opportunity.
Initially, the company's iT4036 phase delay device was designed for test and measurement in 10 Gb/s optical communications. But, as of April it has been rebranded for phase-shift keying (PSK) modulation as used in today's state-of-the-art optical telecommunications networks.
The use of an InP HBT at the core of the device allows consistent phase shifting transformations with signals ranging from direct current up to 12.5 Gb/s alternating currents. Thanks to this and several other design features introduced by the fabless Palo Alto, California, company, customer reports quickly filtered back on a variety of additional uses.
“Because of the bandwidth our customers started to use the iT4036 in other applications,” explained Parker Martineau, GigOptix's marketing communications manager. “Through our research, we were pleasantly surprised to see the potential possibilities.”
Martineau believes the iT4036 to be the only phase-shifter on the market to be able to deal with such a wide range of modulation frequencies. He also points out that the emitter-coupled logic deployed in the InP HBT gives analog control over the resolution of phase delay, whereas competing phase-shifters only offer up to five or eight bits of digital resolution.
GigOptix s HBT design also bucks another trend for phase delays, by providing at least 6 dB of gain, at an example signal amplitude of 200 mV peak-to-peak. In comparison, conventional phase delays introduce several decibels of loss to a signal.
Other than PSK, GigOptix says that a further possible use of the iT4036 device is to phase-match differential drive tunable lasers. It is also hoping to broaden the original test utility of the device from optical communications to microprocessors and other digital applications.
Although the majority of GigOptix s products are based on GaAs devices and targeted at optical communications, the company is hopeful that such a versatile product will continue to grow in popularity across all relevant sectors.
“It's the only product like it in the market and we want our customers to see that,” Martineau explained, “simply because it might make their lives and projects a little easier.”
