made into an actual tunnel-junction collector (Ir T) and provide a sensitive mechanism for fast nonlinear signal mixing and
switching. This can be done, for example,
over the striking frequency range shown
in the figure on the right.
Conclusions and further
Surprising as it is, the transistor laser is
still in its infancy—even after a number
of papers and patents. Even though there
is much more to say and study, in the
interest of brevity, we mention merely
that the transistor laser promises to
become a high-speed-combination coher-ent-optical signal and coherent-electrical
signal integrated circuit element. It has
the potential to make possible much
faster computers and electronics.
Unlike ordinary transistors, the
transistor laser is a three-port device with
an electrical input and electrical output,
plus it has a coherent optical output. In
comparison, the standard transistor is a
simpler, more limited two-port element
with an electrical input and output. The
multi-port capability of the transistor
laser makes it necessary in conventional
circuit analysis and design to reformulate
Kirchhoff’s law, taking into account
energy conservation and not simply current and charge.
Clearly, the multi-port TL offers
much greater topological and device-to-device system design freedom, and it can
be foreseen as making possible higher
performance combination electrical-opti-cal integrated circuits than can be done
with either the transistor itself or even
the more limited two-terminal diode.
Just as the point-contact transistor
and the transistor idea emerged from
Bardeen and Brattain’s surface-effect
studies and experiments of 1947, the
transistor laser came about from the
study of the high-current-density high-
speed HBT. They both began on one
path and emerged on another. Starting
and owing its existence to the HBT,
the transistor laser, an electrically and
optically reinvented quantum-well HBT,
now assists in the further understanding
and study of the HBT itself. The high-
speed HBT, focusing on the critical
transistor base (just as did the Bardeen
and Brattain point-contact transistor),
and taken to the limits of extreme per-
formance, to tiny size and high current
density for high-speed operation, has led
to a unique three-terminal, three-port
transistor laser. The transistor laser, its
base region an active high-gain semicon-
ductor medium admitting to ultra-small
electrical and (cavity) optical size “com-
pression,” may well become a combina-
tion ultimate transistor-laser. It is unique
as a transistor and as a laser. It is both.
Optical output [dBm]
12 12 24
Optical output [dBm]
f1= 2.0 GHz
f2= 2. 1 GHz
5f2+5f1 5f2+4f1 4f2+5f1 4f2+4f1 4f2+3f1 3f2+4f1
2f2+f1 f1+f2 f2+2f1
Microwave signal mixing with a common-emitter tunnel junction transistor laser with
a pair of input sinusoidal signals: one (f1 = 2.0 GHz) at the base at lower impedance
using current modulation, and the other (f2 = 2. 1 GHz) at the collector at higher impedance using voltage modulation. The optical output harmonics extend up to 11th order,
4f1+7f2 = 22. 7 GHz, despite being limited by amplifier bandwidth.
Frequency [GHz] Frequency [GHz]
4 6 8 10 14 16 18 20 22
and Physics. We are also grateful to DARPA
and the ARMY-ARO for their research support. We wish to thank the various postdoc and
research students listed in the references for their
efforts and contributions to this work.
We dedicate this work to John, wherever he is.
Milton Feng ( firstname.lastname@example.org) and
Nick Holonyak Jr. are with the department of electrical and computer engineering at
the University of Illinois at Urbana-Champaign,
Ill., U.S.A. Holonyak is also affiliated with the
department of physics.
One of us (Milton Feng) is grateful for the
support of the Nick Holonyak Jr. Chair of Electrical and Computer Engineering (ECE) and
the other (Nick Holonyak Jr.) appreciates the
support of the Sony John Bardeen Chair of ECE
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